Tag Archives: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)

Off-target CRISPR-Cas9 gene-editing changes closer to home than originally believed according to three studies

Heidi Ledford’s June 25, 2020 article (Note: Links have been removed) for Nature focuses on three studies (not yet peer-reviewed) that viewed together suggest CRISPR (clustered regularly interspaced short palindromic repeats) gene-editing is less like using a pair of scissors to cut out unwanted mutations and more like using a catalyst (a chemical agent which increases chemical reactions) and getting unanticipated and unwatned reactions. Except, it’s an unpredictable catalyst.

A suite of experiments that use the gene-editing tool CRISPR–Cas9 to modify human embryos have revealed how the process can make large, unwanted changes to the genome at or near the target site. [emphasis mine]

The studies were published this month on the preprint server bioRxiv, and have not yet been peer-reviewed1,2,3. But taken together, they give scientists a good look at what some say is an underappreciated risk of CRISPR–Cas9 editing. Previous experiments have revealed that the tool can make ‘off target’ gene mutations far from the target site, but the nearby changes identified in the latest studies can be missed by standard assessment methods.

These safety concerns are likely to inform the ongoing debate over whether scientists should edit human embryos to prevent genetic diseases — a process that is controversial because it creates a permanent change to the genome that can be passed down for generations. “If human embryo editing for reproductive purposes or germline editing were space flight, the new data are the equivalent of having the rocket explode at the launch pad before take-off,” says Fyodor Urnov, who studies genome editing at the University of California, Berkeley, but was not involved in any of the latest research.

These studies,if borne out, offer new concerns (from Ledford’s June 25, 2020 article),

The changes are the result of DNA-repair processes harnessed by genome-editing tools. CRISPR–Cas9 uses a small strand of RNA to direct the Cas9 enzyme to a site in the genome with a similar sequence. The enzyme then cuts both strands of DNA at that site, and the cell’s repair systems heal the gap.

The edits occur during that repair: most often, the cell seals up the cut using an error-prone mechanism that can insert or delete a small number of DNA letters. If researchers provide a DNA template, the cell might sometimes use that sequence to mend the cut, resulting in a true rewrite. But broken DNA can also cause shuffling or loss of a large region of the chromosome.

Previous work using CRISPR in mouse embryos and other kinds of human cell had already demonstrated that editing chromosomes can cause large, unwanted effects4,5. But it was important to demonstrate the work in human embryos as well, says Urnov, because different cell types might respond to genome editing differently.

Such rearrangements could be missed in many experiments, which typically look for other unwanted edits, such as single DNA-letter changes or small insertions or deletions of only a few letters. The latest studies, however, looked specifically for large deletions and chromosomal rearrangements near the target site. [emphasis mine] “This is something that all of us in the scientific community will, starting immediately, take more seriously than we already have,” says Urnov. “This is not a one-time fluke.”

Ledford’s article offers some description and analysis of each of the three papers.Note: All of the research was done with nonviable embryos. For anyone who wants to read the papers for themselves here are links and citations for each of the three,

Frequent loss-of-heterozygosity in CRISPR-Cas9-edited early human embryos by Gregorio Alanis-Lobato, Jasmin Zohren, Afshan McCarthy, Norah M.E. Fogarty, Nada Kubikova, Emily Hardman, Maria Greco, Dagan Wells, James M.A. Turner, Kathy K. Niakan. bioRxiv DOI: https://doi.org/10.1101/2020.06.05.135913 Posted: June 5, 2020

Reading frame restoration at the EYS locus, and allele-specific chromosome removal after Cas9 cleavage in human embryos by Michael V. Zuccaro, Jia Xu, Carl Mitchell, Diego Marin, Raymond Zimmerman, Bhavini Rana, Everett Weinstein, Rebeca T. King, Morgan Smith, Stephen H. Tsang, Robin Goland, Maria Jasin, Rogerio Lobo, Nathan Treff, Dieter Egli. bioRxiv DOI: https://doi.org/10.1101/2020.06.17.149237 Posted June 18, 2020

FREQUENT GENE CONVERSION IN HUMAN EMBRYOS INDUCED BY DOUBLE STRAND BREAKS by Dan Liang, Nuria Marti Gutierrez, Tailai Chen, Yeonmi Lee, Sang-Wook Park, Hong Ma, Amy Koski, Riffat Ahmed, Hayley Darby, Ying Li, Crystal Van Dyken, Aleksei Mikhalchenko, Thanasup Gonmanee, Tomonari Hayama, Han Zhao, Keliang Wu, Jingye Zhang, Zhenzhen Hou, Jumi Park, Chong-Jai Kim, Jianhui Gong, Yilin Yuan, Ying Gu, Yue Shen, Susan B. Olson, Hui Yang, David Battaglia, Thomas O’Leary, Sacha A. Krieg, David M. Lee, Diana H. Wu, P. Barton Duell, Sanjiv Kaul, Jin-Soo Kim, Stephen B. Heitner, Eunju Kang, Zi-Jiang Chen, Paula Amato, Shoukhrat Mitalipov. bioRxiv DOI: https://doi.org/10.1101/2020.06.19.162214 Posted June 20, 2020

These papers are open access.

A July 17, 2018 posting is probably the first time I featured work showing that CRISPR gene-editing can result in off-target effects; it was followed up by a September 20, 2019 posting on the topic.

July 2020 update on Dr. He Jiankui (the CRISPR twins) situation

This was going to be written for January 2020 but sometimes things happen (e.g., a two-part overview of science culture in Canada from 2010-19 morphed into five parts with an addendum and, then, a pandemic). By now (July 28, 2020), Dr. He’s sentencing to three years in jail announced by the Chinese government in January 2020 is old news.

Regardless, it seems a neat and tidy ending to an international scientific scandal concerned with germline-editing which resulted in at least one set of twins, Lulu and Nana. He claimed to have introduced a variant (“Delta 32” variation) of their CCR5 gene. This does occur naturally and scientists have noted that people with this mutation seem to be resistant to HIV and smallpox.

For those not familiar with the events surrounding the announcement, here’s a brief recap. News of the world’s first gene-edited twins’ birth was announced in November 2018 just days before an international meeting group of experts who had agreed on a moratorium in 2015 on exactly that kind of work. The scientist making the announcement about the twins was scheduled for at least one presentation at the meeting, which was to be held in Hong Kong. He did give his presentation but left the meeting shortly afterwards as shock was beginning to abate and fierce criticism was rising. My November 28, 2018 posting (First CRISPR gene-edited babies? Ethics and the science story) offers a timeline of sorts and my initial response.

I subsequently followed up with two mores posts as the story continued to develop. My May 17, 2019 posting (Genes, intelligence, Chinese CRISPR (clustered regularly interspaced short palindromic repeats) babies, and other children) featured news that Dr. He’s gene-editing may have resulted in the twins having improved cognitive skills. Then, more news broke. The title for my June 20, 2019 posting (Greater mortality for the CRISPR twins Lulu and Nana?) is self-explanatory.

I have roughly organized my sources for this posting into two narratives, which I’m contrasting with each other. First, there is one found in the mainstream media (English language), ‘The Popular Narrative’. Second, there is story where Dr. He is viewed more sympathetically and as part of a larger community where there isn’t nearly as much consensus over what should or shouldn’t be done as ‘the popular narrative’ insists.

The popular narrative: Dr. He was a rogue scientist

A December 30, 2019 article for Fast Company by Kristin Toussaint lays out the latest facts (Note: A link has been removed),

… Now, a court in China has sentenced He to three years in prison, according to Xinhua, China’s state-run press agency, for “illegal medical practices.”

The court in China’s southern city of Shenzhen says that He’s team, which included colleagues Zhang Renli and Qin Jinzhou from two medical institutes in Guangdong Province, falsified ethical approval documents and violated China’s “regulations and ethical principles” with their gene-editing work. Zhang was sentenced to two years in jail, and Qin to 18 months with a two-year reprieve, according to Xinhau.

Ian Sample’s December 31, 2020 article for the Guardian offers more detail (Note: Links have been removed),

The court in Shenzhen found He guilty of “illegal medical practices” and in addition to the prison sentence fined him 3m yuan (£327,360), according to the state news agency, Xinhua. Two others on He’s research team received lesser fines and sentences.

“The three accused did not have the proper certification to practise medicine, and in seeking fame and wealth, deliberately violated national regulations in scientific research and medical treatment,” the court said, according to Xinhua. “They’ve crossed the bottom line of ethics in scientific research and medical ethics.”

[…] the court found He had forged documents from an ethics review panel that were used to recruit couples for the research. The couples that enrolled had a man with HIV and a woman without and were offered IVF in return for taking part.

Zhang Renli, who worked with He, was sentenced to two years in prison and fined 1m yuan. Colleague Qin Jinzhou received an 18-month sentence, but with a two-year reprieve, and a 500,000 yuan fine.

He’s experiments, which were carried out on seven embryos in late 2018, sent shockwaves through the medical and scientific world. The work was swiftly condemned for deceiving vulnerable patients and using a risky, untested procedure with no medical justification. Earlier this month, MIT Technology Review released excerpts from an early manuscript of He’s work. It casts serious doubts on his claims to have made the children immune to HIV.

Even as the scientific community turned against He, the scientist defended his work and said he was proud of having created Lulu and Nana. A third child has since been born as a result of the experiments.

Robin Lovell-Badge at the Francis Crick Institute in London said it was “far too premature” for anyone to pursue genome editing on embryos that are intended to lead to pregnancies. “At this stage we do not know if the methods will ever be sufficiently safe and efficient, although the relevant science is progressing rapidly, and new methods can look promising. It is also important to have standards established, including detailed regulatory pathways, and appropriate means of governance.”

A December 30, 2019 article, by Carolyn Y. Johnson for the Washington Post, covers much the same ground although it does go on to suggest that there might be some blame to spread around (Note: Links have been removed),

The Chinese researcher who stunned and alarmed the international scientific community with the announcement that he had created the world’s first gene-edited babies has been sentenced to three years in prison by a court in China.

He Jiankui sparked a bioethical crisis last year when he claimed to have edited the DNA of human embryos, resulting in the birth of twins called Lulu and Nana as well as a possible third pregnancy. The gene editing, which was aimed at making the children immune to HIV, was excoriated by many scientists as a reckless experiment on human subjects that violated basic ethical principles.

The judicial proceedings were not public, and outside experts said it is hard to know what to make of the punishment without the release of the full investigative report or extensive knowledge of Chinese law and the conditions under which He will be incarcerated.

Jennifer Doudna, a biochemist at the University of California at Berkeley who co-invented CRISPR, the gene editing technology that He utilized, has been outspoken in condemning the experiments and has repeatedly said CRISPR is not ready to be used for reproductive purposes.

R. Alta Charo, a fellow at Stanford’s Center for Advanced Study in the Behavioral Sciences, was among a small group of experts who had dinner with He the night before he unveiled his controversial research in Hong Kong in November 2018.

“He Jiankui is an example of somebody who fundamentally didn’t understand, or didn’t want to recognize, what have become international norms around responsible research,” Charo said. “My impression is he allowed his personal ambition to completely cloud rational thinking and judgment.”

Scientists have been testing an array of powerful biotechnology tools to fix genetic diseases in adults. There is tremendous excitement about the possibility of fixing genes that cause serious disease, and the first U.S. patients were treated with CRISPR this year.

But scientists have long drawn a clear moral line between curing genetic diseases in adults and editing and implanting human embryos, which raises the specter of “designer babies.” Those changes and any unanticipated ones could be inherited by future generations — in essence altering the human species.

“The fact that the individual at the center of the story has been punished for his role in it should not distract us from examining what supporting roles were played by others, particularly in the international scientific community and also the environment that shaped and encouraged him to push the limits,” said Benjamin Hurlbut [emphasis mine], associate professor in the School of Life Sciences at Arizona State University.

Stanford University cleared its scientists, including He’s former postdoctoral adviser, Stephen Quake, finding that Quake and others did not participate in the research and had expressed “serious concerns to Dr. He about his work.” A Rice University spokesman said an investigation continues into bioengineering professor Michael Deem, He’s former academic adviser. Deem was listed as a co-author on a paper called “Birth of Twins After Genome Editing for HIV Resistance,” submitted to scientific journals, according to MIT Technology Review.

It’s interesting that it’s only the Chinese scientists who are seen to be punished, symbolically at least. Meanwhile, Stanford clears its scientists of any wrongdoing and Rice University continues to investigate.

Watch for the Hurlbut name (son, Benjamin and father, William) to come up again in the ‘complex narrative’ section.

Criticism of the ‘twins’ CRISPR editing’ research

Antonio Regalado’s December 3, 2020 article for the MIT (Massachusetts Institute of Technology) Technology Review features comments from various experts on an unpublished draft of Dr. He Jiankui’s research

Earlier this year a source sent us a copy of an unpublished manuscript describing the creation of the first gene-edited babies, born last year in China. Today, we are making excerpts of that manuscript public for the first time.

Titled “Birth of Twins After Genome Editing for HIV Resistance,” and 4,699 words long, the still unpublished paper was authored by He Jiankui, the Chinese biophysicist who created the edited twin girls. A second manuscript we also received discusses laboratory research on human and animal embryos.

The metadata in the files we were sent indicate that the two draft papers were edited by He in late November 2018 and appear to be what he initially submitted for publication. Other versions, including a combined manuscript, may also exist. After consideration by at least two prestigious journals, Nature and JAMA, his research remains unpublished.

The text of the twins paper is replete with expansive claims of a medical breakthrough that can “control the HIV epidemic.” It claims “success”—a word used more than once—in using a “novel therapy” to render the girls resistant to HIV. Yet surprisingly, it makes little attempt to prove that the twins really are resistant to the virus. And the text largely ignores data elsewhere in the paper suggesting that the editing went wrong.

We shared the unpublished manuscripts with four experts—a legal scholar, an IVF doctor, an embryologist, and a gene-editing specialist—and asked them for their reactions. Their views were damning. Among them: key claims that He and his team made are not supported by the data; the babies’ parents may have been under pressure to agree to join the experiment; the supposed medical benefits are dubious at best; and the researchers moved forward with creating living human beings before they fully understood the effects of the edits they had made.

1. Why aren’t the doctors among the paper’s authors?

The manuscript begins with a list of the authors—10 of them, mostly from He Jiankui’s lab at the Southern University of Science and Technology, but also including Hua Bai, director of an AIDS support network, who helped recruit couples, and Michael Deem, an American biophysicist whose role is under review by Rice University. (His attorney previously said Deem never agreed to submit the manuscript and sought to remove his name from it.)

It’s a small number of people for such a significant project, and one reason is that some names are missing—notably, the fertility doctors who treated the patients and the obstetrician who delivered the babies. Concealing them may be an attempt to obscure the identities of the patients. However, it also leaves unclear whether or not these doctors understood they were helping to create the first gene-edited babies.

To some, the question of whether the manuscript is trustworthy arises immediately.

Hank Greely, professor of law, Stanford University: We have no, or almost no, independent evidence for anything reported in this paper. Although I believe that the babies probably were DNA-edited and were born, there’s very little evidence for that. Given the circumstances of this case, I am not willing to grant He Jiankui the usual presumption of honesty. 

That last article by Regalado is the purest example I have of how fierce the criticism is and how almost all of it is focused on Dr. He and his Chinese colleagues.

A complex, measured narrative: multiple players in the game

The most sympathetic and, in many ways, the most comprehensive article is an August 1, 2019 piece by Jon Cohen for Science magazine (Note: Links have been removed),

On 10 June 2017, a sunny and hot Saturday in Shenzhen, China, two couples came to the Southern University of Science and Technology (SUSTech) to discuss whether they would participate in a medical experiment that no researcher had ever dared to conduct. The Chinese couples, who were having fertility problems, gathered around a conference table to meet with He Jiankui, a SUSTech biophysicist. Then 33, He (pronounced “HEH”) had a growing reputation in China as a scientist-entrepreneur but was little known outside the country. “We want to tell you some serious things that might be scary,” said He, who was trim from years of playing soccer and wore a gray collared shirt, his cuffs casually unbuttoned.

He simply meant the standard in vitro fertilization (IVF) procedures. But as the discussion progressed, He and his postdoc walked the couples through informed consent forms [emphasis mine] that described what many ethicists and scientists view as a far more frightening proposition. Seventeen months later, the experiment triggered an international controversy, and the worldwide scientific community rejected him. The scandal cost him his university position and the leadership of a biotech company he founded. Commentaries labeled He, who also goes by the nickname JK, a “rogue,” “China’s Frankenstein,” and “stupendously immoral.” [emphases mine]

But that day in the conference room, He’s reputation remained untarnished. As the couples listened and flipped through the forms, occasionally asking questions, two witnesses—one American, the other Chinese—observed [emphasis mine]. Another lab member shot video, which Science has seen [emphasis mine], of part of the 50-minute meeting. He had recruited those couples because the husbands were living with HIV infections kept under control by antiviral drugs. The IVF procedure would use a reliable process called sperm washing to remove the virus before insemination, so father-to-child transmission was not a concern. Rather, He sought couples who had endured HIV-related stigma and discrimination and wanted to spare their children that fate by dramatically reducing their risk of ever becoming infected. [emphasis mine]

He, who for much of his brief career had specialized in sequencing DNA, offered a potential solution: CRISPR, the genome-editing tool that was revolutionizing biology, could alter a gene in IVF embryos to cripple production of an immune cell surface protein, CCR5, that HIV uses to establish an infection. “This technique may be able to produce an IVF baby naturally immunized against AIDS,” one consent form read.[emphasis mine]

The couples’ children could also pass the protective mutation to future generations. The prospect of this irrevocable genetic change is why, since the advent of CRISPR as a genome editor 5 years earlier, the editing of human embryos, eggs, or sperm has been hotly debated. The core issue is whether such germline editing would cross an ethical red line because it could ultimately alter our species. Regulations, some with squishy language, arguably prohibited it in many countries, China included.

Yet opposition was not unanimous. A few months before He met the couples, a committee convened by the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM) concluded in a well-publicized report that human trials of germline editing “might be permitted” if strict criteria were met. The group of scientists, lawyers, bioethicists, and patient advocates spelled out a regulatory framework but cautioned that “these criteria are necessarily vague” because various societies, caregivers, and patients would view them differently. The committee notably did not call for an international ban, arguing instead for governmental regulation as each country deemed appropriate and “voluntary self-regulation pursuant to professional guidelines.”

[…] He hid his plans and deceived his colleagues and superiors, as many people have asserted? A preliminary investigation in China stated that He had forged documents, “dodged supervision,” and misrepresented blood tests—even though no proof of those charges was released [emphasis mine], no outsiders were part of the inquiry, and He has not publicly admitted to any wrongdoing. (CRISPR scientists in China say the He fallout has affected their research.) Many scientists outside China also portrayed He as a rogue actor. “I think there has been a failure of self-regulation by the scientific community because of a lack of transparency,” virologist David Baltimore, a Nobel Prize–winning researcher at the California Institute of Technology (Caltech) in Pasadena and co-chair of the Hong Kong summit, thundered at He after the biophysicist’s only public talk on the experiment.

Because the Chinese government has revealed little and He is not talking, key questions about his actions are hard to answer. Many of his colleagues and confidants also ignored Science‘s requests for interviews. But Ryan Ferrell, a public relations specialist He hired, has cataloged five dozen people who were not part of the study but knew or suspected what He was doing before it became public. Ferrell calls it He’s circle of trust. [emphasis mine]

That circle included leading scientists—among them a Nobel laureate—in China and the United States, business executives, an entrepreneur connected to venture capitalists, authors of the NASEM report, a controversial U.S. IVF specialist [John Zhang] who discussed opening a gene-editing clinic with He [emphasis mine], and at least one Chinese politician. “He had an awful lot of company to be called a ‘rogue,’” says geneticist George Church [emphases mine], a CRISPR pioneer at Harvard University who was not in the circle of trust and is one of the few scientists to defend at least some aspects of He’s experiment.

Some people sharply criticized He when he brought them into the circle; others appear to have welcomed his plans or did nothing. Several went out of their way to distance themselves from He after the furor erupted. For example, the two onlookers in that informed consent meeting were Michael Deem, He’s Ph.D. adviser at Rice University in Houston, Texas, and Yu Jun, a member of the Chinese Academy of Sciences (CAS) and co-founder of the Beijing Genomics Institute, the famed DNA sequencing company in Shenzhen. Deem remains under investigation by Rice for his role in the experiment and would not speak with Science. In a carefully worded statement, Deem’s lawyers later said he “did not meet the parents of the reported CCR5-edited children, or anyone else whose embryos were edited.” But earlier, Deem cooperated with the Associated Press (AP) for its exclusive story revealing the birth of the babies, which reported that Deem was “present in China when potential participants gave their consent and that he ‘absolutely’ thinks they were able to understand the risks. [emphasis mine]”

Yu, who works at CAS’s Beijing Institute of Genomics, acknowledges attending the informed consent meeting with Deem, but he told Science he did not know that He planned to implant gene-edited embryos. “Deem and I were chatting about something else,” says Yu, who has sequenced the genomes of humans, rice, silkworms, and date palms. “What was happening in the room was not my business, and that’s my personality: If it’s not my business, I pay very little attention.”

Some people who know He and have spoken to Science contend it is time for a more open discussion of how the biophysicist formed his circle of confidants and how the larger circle of trust—the one between the scientific community and the public—broke down. Bioethicist William Hurlbut at Stanford University [emphasis mine] in Palo Alto, California, who knew He wanted to conduct the embryo-editing experiment and tried to dissuade him, says that He was “thrown under the bus” by many people who once supported him. “Everyone ran for the exits, in both the U.S. and China. I think everybody would do better if they would just openly admit what they knew and what they did, and then collectively say, ‘Well, people weren’t clear what to do. We should all admit this is an unfamiliar terrain.’”

Steve Lombardi, a former CEO of Helicos, reacted far more charitably. Lombardi, who runs a consulting business in Bridgewater, Connecticut, says Quake introduced him to He to help find investors for Direct Genomics. “He’s your classic, incredibly bright, naïve entrepreneur—I run into them all the time,” Lombardi says. “He had the right instincts for what to do in China and just didn’t know how to do it. So I put him in front of as many people as I could.” Lombardi says He told him about his embryo-editing ambitions in August 2017, asking whether Lombardi could find investors for a new company that focused on “genetic medical tourism” and was based in China or, because of a potentially friendlier regulatory climate, Thailand. “I kept saying to him, ‘You know, you’ve got to deal with the ethics of this and be really sure that you know what you’re doing.’”

In April 2018, He asked Ferrell to handle his media full time. Ferrell was a good fit—he had an undergraduate degree in neuroscience, had spent a year in Beijing studying Chinese, and had helped another company using a pre-CRISPR genome editor. Now that a woman in the trial was pregnant, Ferrell says, He’s “understanding of the gravity of what he had done increased.” Ferrell had misgivings about the experiment, but he quit HDMZ and that August moved to Shenzhen. With the pregnancy already underway, Ferrell reasoned, “It was going to be the biggest science story of that week or longer, no matter what I did.”

MIT Technology Review had broken a story early that morning China time, saying human embryos were being edited and implanted, after reporter Antonio Regalado discovered descriptions of the project that He had posted online, without Ferrell’s knowledge, in an official Chinese clinical trial registry. Now, He gave AP the green light to post a detailed account, which revealed that twin girls—whom He, to protect their identifies, named Lulu and Nana—had been born. Ferrell and He also posted five unfinished YouTube videos explaining and justifying the unprecedented experiment.

“He was fearful that he’d be unable to communicate to the press and the onslaught in a way that would be in any way manageable for him,” Ferrell says. One video tried to forestall eugenics accusations, with He rejecting goals such as enhancing intelligence, changing skin color, and increasing sports performance as “not love.” Still, the group knew it had lost control of the news. [emphasis mine]

… On 7 March 2017, 5 weeks after the California gathering, He submitted a medical ethics approval application to the Shenzhen HarMoniCare Women and Children’s Hospital that outlined the planned CCR5 edit of human embryos. The babies, it claimed, would be resistant to HIV as well as to smallpox and cholera. (The natural CCR5 mutation may have been selected for because it helps carriers survive smallpox and plague, some studies suggest—but they don’t mention cholera.) “This is going to be a great science and medicine achievement ever since the IVF technology which was awarded the Nobel Prize in 2010, and will also bring hope to numerous genetic disease patients,” the application says. Seven people on the ethics committee, chaired by Lin Zhitong—a one-time Direct Genomics director and a HarMoniCare administrator—signed the application, indicating they approved it.

[…] John Zhang, […] [emphasis mine] earned his medical degree in China and a Ph.D. in reproductive biology at the University of Cambridge in the United Kingdom. Zhang had made international headlines himself in September 2016, when New Scientist revealed that he had created the world’s first “three-parent baby” by using mitochondrial DNA from a donor egg to revitalize the egg of a woman with infertility and then inseminating the resulting egg. “This technology holds great hope for ladies with advanced maternal age to have their own children with their own eggs,” Zhang explains in the center’s promotional video, which alternates between Chinese and English. It does not mention that Zhang did the IVF experiment in Mexico because it is not now allowed in the United States. [emphasis mine]

When Science contacted Zhang, the physician initially said he barely knew He: [emphases mine] “I know him just like many people know him, in an academic meeting.”

After his talk [November 2018 at Hong Kong meeting], He immediately drove back to Shenzhen, and his circle of trust began to disintegrate. He has not spoken publicly since. “I don’t think he can recover himself through PR,” says Ferrell, who no longer works for He but recently started to do part-time work for He’s wife. “He has to do other service to the world.”

Calls for a moratorium on human germline editing have increased, although at the end of the Hong Kong summit, the organizing committee declined in its consensus to call for a ban. China has stiffened its regulations on work with human embryos, and Chinese bioethicists in a Nature editorial about the incident urged the country to confront “the eugenic thinking that has persisted among a small proportion of Chinese scholars.”

Church, who has many CRISPR collaborations in China, finds it inconceivable that He’s work surprised the Chinese government. China has “the best surveillance system in the world,” he says. “I conclude that they were totally aware of what he was doing at every step of the way, especially because he wasn’t particularly secretive about it.”

Benjamin Hurlbut, William’s son and a historian of biomedicine at Arizona State University in Tempe, says leaders in the scientific community should take a hard look at their actions, too. [emphases mine] He thinks the 2017 NASEM report helped give rise to He by following a well-established approach to guiding science: appointing an elite group to decide how scientists should be regulated. Benjamin Hurlbut, whose book Experiments in Democracy explores the governance of embryo research and bioethics, questions why small, scientist-led groups—à la the totemic Asilomar conference held in 1975 to discuss the future of recombinant DNA research—are seen as the best way to shape thinking about new technologies. Hurlbut has called for a “global observatory for gene editing” to convene meetings with diverse perspectives.

The prevailing notion that the scientific community simply “failed to see the rogue among the responsible,” Hurlbut says, is a convenient narrative for those scientific leaders and inhibits their ability to learn from such failures. [emphases mine] “It puts them on the right side of history,” he says. They failed to paint a bright enough red line, Hurlbut contends. “They are not on the right side of history because they contributed to this.”

If you have the time, I strongly recommend reading Cohen’s piece in its entirety. You’ll find links to the reports and more articles with in-depth reporting on this topic.

A little kindness and no regrets

William Hurlbut was interviewed in an As it happens (Canadian Broadcasting Corporation’ CBC) radio programme segment on December 30, 2020. This is an excerpt from the story transcript written by Sheena Goodyear (Note: A link has been removed),

Dr. William Hurlbut, a physician and professor of neural-biology at Stanford University, says he tried to warn He to slow down before it was too late. Here is part of his conversation with As It Happens guest host Helen Mann.

What was your reaction to the news that Dr. He had been sentenced to three years in prison?

My first reaction was one of sadness because I know Dr. He — who we call J.K., that’s his nickname.

I spent quite a few hours talking with him, and I’m just sad that this worked out this way. It didn’t work out well for him or for his country or for the world, in some sense.

Except the one good thing is it’s alerted us, it’s awakened the world, to the seriousness of the issues that are coming down toward us with biotechnology, especially in genetics.

How does he feel about [how] not just the Chinese government, but the world generally, responded to his experiment?

He was surprised, personally. But I had actually warned him that he was proceeding too fast, and I didn’t know he had implanted embryos.

We had several conversations before this was disclosed, and I warned him to go more slowly and to keep in conversation with the rest of the international scientific community, and more broadly the international perspectives on social and ethical matters.

He was doing that to some extent, but not deeply enough and not transparently enough.

It sounds like you were very thoughtful in the conversations you had with him and the advice you gave him. And I guess you operated with what you had. But do you have any regrets yourself?

I don’t have any regrets about the way I conducted myself. I regret that this happened this way for J.K., who is a very bright person, and a very nice person, a humble person.

He grew up in a poor urban farming village. He told me that at one point he wanted to ask out a certain girl that he thought was really pretty … but he was embarrassed to do so because her family owned the restaurant. And so you see how humble his origins were.

By the way, he did end up asking her out and he ended up marrying her, which is a happy story, except now they’re separated for years of crucial time, and they have little children. 

I know this is a bigger story than just J.K. and his family. But there’s a personal story to it too.

What happens He Jiankui? … Is his research career over?

It’s hard to imagine that a nation like China would not give him some some useful role in their society. A very intelligent and very well-educated young man. 

But on the other hand, he will be forever a sign of a very crucial and difficult moment for the human species. He’s not going outlive that.

It’s going to be interesting. I hope I get a chance to have good conversations with him again and hear his internal ruminations and perspectives on it all.

This (“I don’t have any regrets about the way I conducted myself”) is where Hurlbut lost me. I think he could have suggested that he’d reviewed and rethought everything and feels that he and others could have done better and maybe they need to rethink how scientists are trained and how we talk about science, genetics, and emerging technology. Interestingly, it’s his son who comes up with something closer to what I’m suggesting (this excerpt was quoted earlier in this posting from a December 30, 2019 article, by Carolyn Y. Johnson for the Washington Post),

“The fact that the individual at the center of the story has been punished for his role in it should not distract us from examining what supporting roles were played by others, particularly in the international scientific community and also the environment that shaped and encouraged him to push the limits,” said Benjamin Hurlbut [emphasis mine], associate professor in the School of Life Sciences at Arizona State University.

The man who CRISPRs himself approves

Josiah Zayner publicly injected himself with CRISPR in a demonstration (see my January 25, 2018 posting for details about Zayner, his demonstration, and his plans). As you might expect, his take on the He affair is quite individual. From a January 2, 2020 article for STAT, Zayner presents the case for Dr. He’s work (Note: Links have been removed),

When I saw the news that He Jiankui and colleagues had been sentenced to three years in prison for the first human embryo gene editing and implantation experiments, all I could think was, “How will we look back at what they had done in 100 years?”

When the scientist described his research and revealed the births of gene edited twin girls at the [Second] International Summit on Human Genome Editing in Hong Kong in late November 2018, I stayed up into the early hours of the morning in Oakland, Calif., watching it. Afterward, I couldn’t sleep for a few days and couldn’t stop thinking about his achievement.

This was the first time a viable human embryo was edited and allowed to live past 14 days, much less the first time such an embryo was implanted and the baby brought to term.

The majority of scientists were outraged at the ethics of what had taken place, despite having very little information on what had actually occurred.

To me, no matter how abhorrent one views [sic] the research, it represents a substantial step forward in human embryo editing. Now there is a clear path forward that anyone can follow when before it had been only a dream.

As long as the children He Jiankui engineered haven’t been harmed by the experiment, he is just a scientist who forged some documents to convince medical doctors to implant gene-edited embryos. The 4-minute mile of human genetic engineering has been broken. It will happen again.

The academic establishment and federal funding regulations have made it easy to control the number of heretical scientists. We rarely if ever hear of individuals pushing the ethical and legal boundaries of science.

The rise of the biohacker is changing that.

A biohacker is a scientist who exists outside academia or an institution. By this definition, He Jiankui is a biohacker. I’m also part of this community, and helped build an organization to support it.

Such individuals have much more freedom than “traditional” scientists because scientific regulation in the U.S. is very much institutionally enforced by the universities, research organizations, or grant-giving agencies. But if you are your own institution and don’t require federal grants, who can police you? If you don’t tell anyone what you are doing, there is no way to stop you — especially since there is no government agency actively trying to stop people from editing embryos.

… When a human embryo being edited and implanted is no longer interesting enough for a news story, will we still view He Jiankui as a villain?

I don’t think we will. But even if we do, He Jiankui will be remembered and talked about more than any scientist of our day. Although that may seriously aggravate many scientists and bioethicists, I think he deserves that honor.

Josiah Zayner is CEO of The ODIN, a company that teaches people how to do genetic engineering in their homes.

You can find The ODIN here.

Final comments

There can’t be any question that this was inevitable. One needs only to take a brief stroll through the history of science to know that scientists are going to push boundaries or, as in this case, press past an ill-defined grey zone.

The only scientists who are being publicly punished for hubris are Dr. He Jiankui and his two colleagues in China. Dr. Michael Deem is still working for Rice University as far as I can determine. Here’s how the Wikipedia entry for the He Jiankui Affair describes the investigation (Note: Links have been removed),

Michael W. Deem, an American bioengineering professor at Rice University and He’s doctoral advisor, was involved in the research, and was present when people involved in He’s study gave consent.[24] He was the only non-Chinese out of 10 authors listed in the manuscript submitted to Nature.[30] Deem came under investigation by Rice University after news of the work was made public.[58] As of 31 December 2019, the university had not released a decision.[59] [emphasis mine]

Meanwhile the scientists at Stanford are cleared. While there are comments about the Chinese government not being transparent, it seems to me that US universities are just as opaque.

What seems missing from all this discussion and opprobrium is that the CRISPR technology itself is problematic. My September 20, 2019 post features research into off-target results from CRISPR gene-editing and, prior, there was this July 17, 2018 posting (The CRISPR [clustered regularly interspaced short palindromic repeats]-CAS9 gene-editing technique may cause new genetic damage kerfuffle).

I’d like to see more discussion and, in line with Benjamin Hurlbut’s thinking, I’d like to see more than a small group of experts talking to each other as part of the process especially here in Canada and in light of efforts to remove our ban on germline-editing (see my April 26, 2019 posting for more about those efforts).

New US regulations exempt many gene-edited crops from government oversight

A June 1, 2020 essay by Maywa Montenegro (Postdoctoral Fellow, University of California at Davis) for The Conversation posits that new regulations (which in fact result in deregulation) are likely to create problems,

In May [2020], federal regulators finalized a new biotechnology policy that will bring sweeping changes to the U.S. food system. Dubbed “SECURE,” the rule revises U.S. Department of Agriculture regulations over genetically engineered plants, automatically exempting many gene-edited crops from government oversight. Companies and labs will be allowed to “self-determine” whether or not a crop should undergo regulatory review or environmental risk assessment.

Initial responses to this new policy have followed familiar fault lines in the food community. Seed industry trade groups and biotech firms hailed the rule as “important to support continuing innovation.” Environmental and small farmer NGOs called the USDA’s decision “shameful” and less attentive to public well-being than to agribusiness’s bottom line.

But the gene-editing tool CRISPR was supposed to break the impasse in old GM wars by making biotechnology more widely affordable, accessible and thus democratic.

In my research, I study how biotechnology affects transitions to sustainable food systems. It’s clear that since 2012 the swelling R&D pipeline of gene-edited grains, fruits and vegetables, fish and livestock has forced U.S. agencies to respond to the so-called CRISPR revolution.

Yet this rule change has a number of people in the food and scientific communities concerned. To me, it reflects the lack of accountability and trust between the public and government agencies setting policies.

Is there a better way?

… I have developed a set of principles and practices for governing CRISPR based on dialogue with front-line communities who are most affected by the technologies others usher in. Communities don’t just have to adopt or refuse technology – they can co-create [emphasis mine] it.

One way to move forward in the U.S. is to take advantage of common ground between sustainable agriculture movements and CRISPR scientists. The struggle over USDA rules suggests that few outside of industry believe self-regulation is fair, wise or scientific.

h/t: June 1, 2020 news item on phys.org

If you have the time and the inclination, do read the essay in its entirety.

Anyone who has read my COVID-19 op-ed for the Canadian Science Policy may see some similarity between Montenegro’s “co-create” and this from my May 15, 2020 posting which included my reference materials or this version on the Canadian Science Policy Centre where you can find many other COVID-19 op-eds)

In addition to engaging experts as we navigate our way into the future, we can look to artists, writers, citizen scientists, elders, indigenous communities, rural and urban communities, politicians, philosophers, ethicists, religious leaders, and bureaucrats of all stripes for more insight into the potential for collateral and unintended consequences.

To be clear, I think times of crises are when a lot of people call for more co-creation and input. Here’s more about Montenegro’s work on her profile page (which includes her academic credentials, research interests and publications) on the University of California at Berkeley’s Department of Environmental Science, Policy, and Management webspace. She seems to have been making the call for years.

I am a US-Dutch-Peruvian citizen who grew up in Appalachia, studied molecular biology in the Northeast, worked as a journalist in New York City, and then migrated to the left coast to pursue a PhD. My indigenous ancestry, smallholder family history, and the colonizing/decolonizing experiences of both the Netherlands and Peru informs my personal and professional interests in seeds and agrobiodiversity. My background engenders a strong desire to explore synergies between western science and the indigenous/traditional knowledge systems that have historically been devalued and marginalized.

Trained in molecular biology, science writing, and now, a range of critical social and ecological theory, I incorporate these perspectives into research on seeds.

I am particularly interested in the relationship between formal seed systems – characterized by professional breeding, certification, intellectual property – and commercial sale and informal seed systems through which farmers traditionally save, exchange, and sell seeds. …

You can find more on her Twitter feed, which is where I discovered a call for papers for a “Special Feature: Gene Editing the Food System” in the journal, Elementa: Science of the Anthropocene. They have a rolling deadline, which started in February 2020. At this time, there is one paper in the series,

Democratizing CRISPR? Stories, practices, and politics of science and governance on the agricultural gene editing frontier by Maywa Montenegro de Wit. Elem Sci Anth, 8(1), p.9. DOI: http://doi.org/10.1525/elementa.405 Published February 25, 2020

The paper is open access. Interestingly, the guest editor is Elizabeth Fitting of Dalhousie University in Nova Scotia, Canada.

The Broad Institute gives us another reason to love CRISPR

More and more, this resembles a public relations campaign. First, CRISPR (clustered regularly interspersed short palindromic repeats) gene editing is going to be helpful with COVID-19 and now it can help us to deal with conservation issues. (See my May 26, 2020 posting about the latest CRISPR doings as of May 7, 2020; included is a brief description of the patent dispute between Broad Institute and UC Berkeley and musings about a public relations campaign.)

A May 21, 2020 news item on ScienceDaily announces how CRISPR could be useful for conservation,

The gene-editing technology CRISPR has been used for a variety of agricultural and public health purposes — from growing disease-resistant crops to, more recently, a diagnostic test for the virus that causes COVID-19. Now a study involving fish that look nearly identical to the endangered Delta smelt finds that CRISPR can be a conservation and resource management tool, as well. The researchers think its ability to rapidly detect and differentiate among species could revolutionize environmental monitoring.

Caption: Longfin smelt can be difficult to differentiate from endangered Delta smelt. Here, a longfin smelt is swabbed for genetic identification through a CRISPR tool called SHERLOCK. Credit: Alisha Goodbla/UC Davis

A May 21, 2020 University of California at Davis (UC Davis) news release (also on EurekAlert) by Kat Kerlin, which originated the news item, provides more detail (Note: A link has been removed),

The study, published in the journal Molecular Ecology Resources, was led by scientists at the University of California, Davis, and the California Department of Water Resources in collaboration with MIT Broad Institute [emphasis mine].

As a proof of concept, it found that the CRISPR-based detection platform SHERLOCK (Specific High-sensitivity Enzymatic Reporter Unlocking) [emphasis mine] was able to genetically distinguish threatened fish species from similar-looking nonnative species in nearly real time, with no need to extract DNA.

“CRISPR can do a lot more than edit genomes,” said co-author Andrea Schreier, an adjunct assistant professor in the UC Davis animal science department. “It can be used for some really cool ecological applications, and we’re just now exploring that.”

WHEN GETTING IT WRONG IS A BIG DEAL

The scientists focused on three fish species of management concern in the San Francisco Estuary: the U.S. threatened and California endangered Delta smelt, the California threatened longfin smelt and the nonnative wakasagi. These three species are notoriously difficult to visually identify, particularly in their younger stages.

Hundreds of thousands of Delta smelt once lived in the Sacramento-San Joaquin Delta before the population crashed in the 1980s. Only a few thousand are estimated to remain in the wild.

“When you’re trying to identify an endangered species, getting it wrong is a big deal,” said lead author Melinda Baerwald, a project scientist at UC Davis at the time the study was conceived and currently an environmental program manager with California Department of Water Resources.

For example, state and federal water pumping projects have to reduce water exports if enough endangered species, like Delta smelt or winter-run chinook salmon, get sucked into the pumps. Rapid identification makes real-time decision making about water operations feasible.

FROM HOURS TO MINUTES

Typically to accurately identify the species, researchers rub a swab over the fish to collect a mucus sample or take a fin clip for a tissue sample. Then they drive or ship it to a lab for a genetic identification test and await the results. Not counting travel time, that can take, at best, about four hours.

SHERLOCK shortens this process from hours to minutes. Researchers can identify the species within about 20 minutes, at remote locations, noninvasively, with no specialized lab equipment. Instead, they use either a handheld fluorescence reader or a flow strip that works much like a pregnancy test — a band on the strip shows if the target species is present.

“Anyone working anywhere could use this tool to quickly come up with a species identification,” Schreier said.

OTHER CRYPTIC CRITTERS

While the three fish species were the only animals tested for this study, the researchers expect the method could be used for other species, though more research is needed to confirm. If so, this sort of onsite, real-time capability may be useful for confirming species at crime scenes, in the animal trade at border crossings, for monitoring poaching, and for other animal and human health applications.

“There are a lot of cryptic species we can’t accurately identify with our naked eye,” Baerwald said. “Our partners at MIT are really interested in pathogen detection for humans. We’re interested in pathogen detection for animals as well as using the tool for other conservation issues.”

Here’s a link to and a citation for the paper,

Rapid and accurate species identification for ecological studies and monitoring using CRISPR‐based SHERLOCK by Melinda R. Baerwald, Alisha M. Goodbla, Raman P. Nagarajan, Jonathan S. Gootenberg, Omar O. Abudayyeh, Feng Zhang, Andrea D. Schreier. Molecular Ecology Resources https://doi.org/10.1111/1755-0998.13186 First published: 12 May 2020

This paper is behind a paywall.

The business of CRISPR

SHERLOCK™, is a trademark for what Sherlock Biosciences calls one of its engineering biology platforms. From the Sherlock Biosciences Technology webpage,

What is SHERLOCK™?

SHERLOCK is an evolution of CRISPR technology, which others use to make precise edits in genetic code. SHERLOCK can detect the unique genetic fingerprints of virtually any DNA or RNA sequence in any organism or pathogen. Developed by our founders and licensed exclusively from the Broad Institute, SHERLOCK is a method for single molecule detection of nucleic acid targets and stands for Specific High Sensitivity Enzymatic Reporter unLOCKing. It works by amplifying genetic sequences and programming a CRISPR molecule to detect the presence of a specific genetic signature in a sample, which can also be quantified. When it finds those signatures, the CRISPR enzyme is activated and releases a robust signal. This signal can be adapted to work on a simple paper strip test, in laboratory equipment, or to provide an electrochemical readout that can be read with a mobile phone.

However, things get a little more confusing when you look at the Broad Institute’s Developing Diagnostics and Treatments webpage,

Ensuring the SHERLOCK diagnostic platform is easily accessible, especially in the developing world, where the need for inexpensive, reliable, field-based diagnostics is the most urgent

SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing) is a CRISPR-based diagnostic tool that is rapid, inexpensive, and highly sensitive, with the potential to have a transformative effect on research and global public health. The SHERLOCK platform can detect viruses, bacteria, or other targets in clinical samples such as urine or blood, and reveal results on a paper strip — without the need for extensive specialized equipment. This technology could potentially be used to aid the response to infectious disease outbreaks, monitor antibiotic resistance, detect cancer, and more. SHERLOCK tools are freely available [emphasis mine] for academic research worldwide, and the Broad Institute’s licensing framework [emphasis mine] ensures that the SHERLOCK diagnostic platform is easily accessible in the developing world, where inexpensive, reliable, field-based diagnostics are urgently needed.

Here’s what I suspect. as stated, the Broad Institute has free SHERLOCK licenses for academic institutions and not-for-profit organizations but Sherlock Biosciences, a Broad Institute spinoff company, is for-profit and has trademarked SHERLOCK for commercial purposes.

Final thoughts

This looks like a relatively subtle campaign to influence public perceptions. Genetic modification or genetic engineering as exemplified by the CRISPR gene editing technique is a force for the good of all. It will help us in our hour of need (COVID-19 pandemic) and it can help us save various species and better manage our resources.

This contrasts greatly with the publicity generated by the CRISPR twins situation where a scientist claimed to have successfully edited the germline for twins, Lulu and Nana. This was done despite a voluntary, worldwide moratorium on germline editing of viable embryos. (Search the terms [either here or on a standard search engine] ‘CRISPR twins’, ‘Lulu and Nana’, and/or ‘He Jiankui’ for details about the scandal.

In addition to presenting CRISPR as beneficial in the short term rather than the distant future, this publicity also subtly positions the Broad Institute as CRISPR’s owner.

Or, maybe I’m wrong. Regardless, I’m watching.

US Food and Drug Administration (FDA) gives first authorization for CRISPR (clustered regularly interspersed short palindromic repeats) use in COVID-19 crisis

Clustered regularly interspersed short palindromic repeats (CRISPR) gene editing has been largely confined to laboratory use or tested in agricultural trials. I believe that is true worldwide excepting the CRISPR twin scandal. (There are numerous postings about the CRISPR twins here including a Nov. 28, 2018 post, a May 17, 2019 post, and a June 20, 2019 post. Update: It was reported (3rd. para.) in December 2019 that He had been sentenced to three years jail time.)

Connie Lin in a May 7, 2020 article for Fast Company reports on this surprising decision by the US Food and Drug Administration (FDA), Note: A link has been removed),

The U.S. Food and Drug Administration has granted Emergency Use Authorization to a COVID-19 test that uses controversial gene-editing technology CRISPR.

This marks the first time CRISPR has been authorized by the FDA, although only for the purpose of detecting the coronavirus, and not for its far more contentious applications. The new test kit, developed by Cambridge, Massachusetts-based Sherlock Biosciences, will be deployed in laboratories certified to carry out high-complexity procedures and is “rapid,” returning results in about an hour as opposed to those that rely on the standard polymerase chain reaction method, which typically requires six hours.

The announcement was made in the FDA’s Coronavirus (COVID-19) Update: May 7, 2020 Daily Roundup (4th item in the bulleted list), Or, you can read the May 6, 2020 letter (PDF) sent to John Vozella of Sherlock Biosciences by the FDA.

As well, there’s the May 7, 2020 Sherlock BioSciences news release (the most informative of the lot),

Sherlock Biosciences, an Engineering Biology company dedicated to making diagnostic testing better, faster and more affordable, today announced the company has received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) for its Sherlock™ CRISPR SARS-CoV-2 kit for the detection of the virus that causes COVID-19, providing results in approximately one hour.

“While it has only been a little over a year since the launch of Sherlock Biosciences, today we have made history with the very first FDA-authorized use of CRISPR technology, which will be used to rapidly identify the virus that causes COVID-19,” said Rahul Dhanda, co-founder, president and CEO of Sherlock Biosciences. “We are committed to providing this initial wave of testing kits to physicians, laboratory experts and researchers worldwide to enable them to assist frontline workers leading the charge against this pandemic.”

The Sherlock™ CRISPR SARS-CoV-2 test kit is designed for use in laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, to perform high complexity tests. Based on the SHERLOCK method, which stands for Specific High-sensitivity Enzymatic Reporter unLOCKing, the kit works by programming a CRISPR molecule to detect the presence of a specific genetic signature – in this case, the genetic signature for SARS-CoV-2 – in a nasal swab, nasopharyngeal swab, oropharyngeal swab or bronchoalveolar lavage (BAL) specimen. When the signature is found, the CRISPR enzyme is activated and releases a detectable signal. In addition to SHERLOCK, the company is also developing its INSPECTR™ platform to create an instrument-free, handheld test – similar to that of an at-home pregnancy test – that utilizes Sherlock Biosciences’ Synthetic Biology platform to provide rapid detection of a genetic match of the SARS-CoV-2 virus.

“When our lab collaborated with Dr. Feng Zhang’s team to develop SHERLOCK, we believed that this CRISPR-based diagnostic method would have a significant impact on global health,” said James J. Collins, co-founder and board member of Sherlock Biosciences and Termeer Professor of Medical Engineering and Science for MIT’s Institute for Medical Engineering and Science (IMES) and Department of Biological Engineering. “During what is a major healthcare crisis across the globe, we are heartened that the first FDA-authorized use of CRISPR will aid in the fight against this global COVID-19 pandemic.”

Access to rapid diagnostics is critical for combating this pandemic and is a primary focus for Sherlock Biosciences co-founder and board member, David R. Walt, Ph.D., who co-leads the Mass [Massachusetts] General Brigham Center for COVID Innovation.

“SHERLOCK enables rapid identification of a single alteration in a DNA or RNA sequence in a single molecule,” said Dr. Walt. “That precision, coupled with its capability to be deployed to multiplex over 100 targets or as a simple point-of-care system, will make it a critical addition to the arsenal of rapid diagnostics already being used to detect COVID-19.”

This development is particularly interesting since there was a major intellectual property dispute over CRISPR between the Broad Institute (a Harvard University and Massachusetts Institute of Technology [MIT] joint initiative), and the University of California at Berkeley (UC Berkeley). The Broad Institute mostly won in the first round of the patent fight, as I noted in a March 15, 2017 post but, as far as I’m aware, UC Berkeley is still disputing that decision.

In the period before receiving authorization, it appears that Sherlock Biosciences was doing a little public relations and ‘consciousness raising’ work. Here’s a sample from a May 5, 2020 article by Sharon Begley for STAT (Note: Links have been removed),

The revolutionary genetic technique better known for its potential to cure thousands of inherited diseases could also solve the challenge of Covid-19 diagnostic testing, scientists announced on Tuesday. A team headed by biologist Feng Zhang of the McGovern Institute at MIT and the Broad Institute has repurposed the genome-editing tool CRISPR into a test able to quickly detect as few as 100 coronavirus particles in a swab or saliva sample.

Crucially, the technique, dubbed a “one pot” protocol, works in a single test tube and does not require the many specialty chemicals, or reagents, whose shortage has hampered the rollout of widespread Covid-19 testing in the U.S. It takes about an hour to get results, requires minimal handling, and in preliminary studies has been highly accurate, Zhang told STAT. He and his colleagues, led by the McGovern’s Jonathan Gootenberg and Omar Abudayyeh, released the protocol on their STOPCovid.science website.

Because the test has not been approved by the Food and Drug Administration, it is only for research purposes for now. But minutes before speaking to STAT on Monday, Zhang and his colleagues were on a conference call with FDA officials about what they needed to do to receive an “emergency use authorization” that would allow clinical use of the test. The FDA has used EUAs to fast-track Covid-19 diagnostics as well as experimental therapies, including remdesivir, after less extensive testing than usually required.

For an EUA, the agency will require the scientists to validate the test, which they call STOPCovid, on dozens to hundreds of samples. Although “it is still early in the process,” Zhang said, he and his colleagues are confident enough in its accuracy that they are conferring with potential commercial partners who could turn the test into a cartridge-like device, similar to a pregnancy test, enabling Covid-19 testing at doctor offices and other point-of-care sites.

“It could potentially even be used at home or at workplaces,” Zhang said. “It’s inexpensive, does not require a lab, and can return results within an hour using a paper strip, not unlike a pregnancy test. This helps address the urgent need for widespread, accurate, inexpensive, and accessible Covid-19 testing.” Public health experts say the availability of such a test is one of the keys to safely reopening society, which will require widespread testing, and then tracing and possibly isolating the contacts of those who test positive.

If you have time, do read Begley’s in full.

The CRISPR yogurt story and a hornless cattle update

Clustered regularly interspaced short palindromic repeats (CRISPR) does not and never has made much sense to me. I understand each word individually it’s just that I’ve never thought they made much sense strung together that way. It’s taken years but I’ve finally found out what the words (when strung together that way) mean and the origins for the phrase. Hint: it’s all about the phages.

Apparently, it all started with yogurt as Cynthia Graber and Nicola Twilley of Gastropod discuss on their podcast, “4 CRISPR experts on how gene editing is changing the future of food.” During the course of the podcast they explain the ‘phraseology’ issue, mention hornless cattle (I have an update to the information in the podcast later in this posting), and so much more.

CRISPR started with yogurt

You’ll find the podcast (almost 50 minutes long) here on an Oct. 11, 2019 posting on the Genetic Literacy Project. If you need a little more encouragement, here’s how the podcast is described,

To understand how CRISPR will transform our food, we begin our episode at Dupont’s yoghurt culture facility in Madison, Wisconsin. Senior scientist Dennis Romero tells us the story of CRISPR’s accidental discovery—and its undercover but ubiquitous presence in the dairy aisles today.

Jennifer Kuzma and Yiping Qi help us understand the technology’s potential, both good and bad, as well as how it might be regulated and labeled. And Joyce Van Eck, a plant geneticist at the Boyce Thompson Institute in Ithaca, New York, tells us the story of how she is using CRISPR, combined with her understanding of tomato genetics, to fast-track the domestication of one of the Americas’ most delicious orphan crops [groundcherries].

I featured Van Eck’s work with groundcherries last year in a November 28, 2018 posting and I don’t think she’s published any new work about the fruit since. As for Kuzma’s point that there should be more transparency where genetically modified food is concerned, Canadian consumers were surprised (shocked) in 2017 to find out that genetically modified Atlantic salmon had been introduced into the food market without any notification (my September 13, 2017 posting; scroll down to the Fish subheading; Note: The WordPress ‘updated version from Hell’ has affected some of the formatting on the page).

The earliest article on CRISPR and yogurt that I’ve found is a January 1, 2015 article by Kerry Grens for The Scientist,

Two years ago, a genome-editing tool referred to as CRISPR (clustered regularly interspaced short palindromic repeats) burst onto the scene and swept through laboratories faster than you can say “adaptive immunity.” Bacteria and archaea evolved CRISPR eons before clever researchers harnessed the system to make very precise changes to pretty much any sequence in just about any genome.

But life scientists weren’t the first to get hip to CRISPR’s potential. For nearly a decade, cheese and yogurt makers have been relying on CRISPR to produce starter cultures that are better able to fend off bacteriophage attacks. “It’s a very efficient way to get rid of viruses for bacteria,” says Martin Kullen, the global R&D technology leader of Health and Protection at DuPont Nutrition & Health. “CRISPR’s been an important part of our solution to avoid food waste.”

Phage infection of starter cultures is a widespread and significant problem in the dairy-product business, one that’s been around as long as people have been making cheese. Patrick Derkx, senior director of innovation at Denmark-based Chr. Hansen, one of the world’s largest culture suppliers, estimates that the quality of about two percent of cheese production worldwide suffers from phage attacks. Infection can also slow the acidification of milk starter cultures, thereby reducing creameries’ capacity by up to about 10 percent, Derkx estimates.
In the early 2000s, Philippe Horvath and Rodolphe Barrangou of Danisco (later acquired by DuPont) and their colleagues were first introduced to CRISPR while sequencing Streptococcus thermophilus, a workhorse of yogurt and cheese production. Initially, says Barrangou, they had no idea of the purpose of the CRISPR sequences. But as his group sequenced different strains of the bacteria, they began to realize that CRISPR might be related to phage infection and subsequent immune defense. “That was an eye-opening moment when we first thought of the link between CRISPR sequencing content and phage resistance,” says Barrangou, who joined the faculty of North Carolina State University in 2013.

One last bit before getting to the hornless cattle, scientist Yi Li has a November 15, 2018 posting on the GLP website about his work with gene editing and food crops,

I’m a plant geneticist and one of my top priorities is developing tools to engineer woody plants such as citrus trees that can resist the greening disease, Huanglongbing (HLB), which has devastated these trees around the world. First detected in Florida in 2005, the disease has decimated the state’s US$9 billion citrus crop, leading to a 75 percent decline in its orange production in 2017. Because citrus trees take five to 10 years before they produce fruits, our new technique – which has been nominated by many editors-in-chief as one of the groundbreaking approaches of 2017 that has the potential to change the world – may accelerate the development of non-GMO citrus trees that are HLB-resistant.

Genetically modified vs. gene edited

You may wonder why the plants we create with our new DNA editing technique are not considered GMO? It’s a good question.

Genetically modified refers to plants and animals that have been altered in a way that wouldn’t have arisen naturally through evolution. A very obvious example of this involves transferring a gene from one species to another to endow the organism with a new trait – like pest resistance or drought tolerance.

But in our work, we are not cutting and pasting genes from animals or bacteria into plants. We are using genome editing technologies to introduce new plant traits by directly rewriting the plants’ genetic code.

This is faster and more precise than conventional breeding, is less controversial than GMO techniques, and can shave years or even decades off the time it takes to develop new crop varieties for farmers.

There is also another incentive to opt for using gene editing to create designer crops. On March 28, 2018, U.S. Secretary of Agriculture Sonny Perdue announced that the USDA wouldn’t regulate new plant varieties developed with new technologies like genome editing that would yield plants indistinguishable from those developed through traditional breeding methods. By contrast, a plant that includes a gene or genes from another organism, such as bacteria, is considered a GMO. This is another reason why many researchers and companies prefer using CRISPR in agriculture whenever it is possible.

As the Gatropod’casters note, there’s more than one side to the gene editing story and not everyone is comfortable with the notion of cavalierly changing genetic codes when so much is still unknown.

Hornless cattle update

First mentioned here in a November 28, 2018 posting, hornless cattle have been in the news again. From an October 7, 2019 news item on ScienceDaily,

For the past two years, researchers at the University of California, Davis, have been studying six offspring of a dairy bull, genome-edited to prevent it from growing horns. This technology has been proposed as an alternative to dehorning, a common management practice performed to protect other cattle and human handlers from injuries.

UC Davis scientists have just published their findings in the journal Nature Biotechnology. They report that none of the bull’s offspring developed horns, as expected, and blood work and physical exams of the calves found they were all healthy. The researchers also sequenced the genomes of the calves and their parents and analyzed these genomic sequences, looking for any unexpected changes.

An October 7, 2019 UC Davis news release (also on EurekAlert), which originated the news item, provides more detail about the research (I have checked the UC Davis website here and the October 2019 update appears to be the latest available publicly as of February 5, 2020),

All data were shared with the U.S. Food and Drug Administration. Analysis by FDA scientists revealed a fragment of bacterial DNA, used to deliver the hornless trait to the bull, had integrated alongside one of the two hornless genetic variants, or alleles, that were generated by genome-editing in the bull. UC Davis researchers further validated this finding.

“Our study found that two calves inherited the naturally-occurring hornless allele and four calves additionally inherited a fragment of bacterial DNA, known as a plasmid,” said corresponding author Alison Van Eenennaam, with the UC Davis Department of Animal Science.

Plasmid integration can be addressed by screening and selection, in this case, selecting the two offspring of the genome-edited hornless bull that inherited only the naturally occurring allele.

“This type of screening is routinely done in plant breeding where genome editing frequently involves a step that includes a plasmid integration,” said Van Eenennaam.

Van Eenennaam said the plasmid does not harm the animals, but the integration technically made the genome-edited bull a GMO, because it contained foreign DNA from another species, in this case a bacterial plasmid.

“We’ve demonstrated that healthy hornless calves with only the intended edit can be produced, and we provided data to help inform the process for evaluating genome-edited animals,” said Van Eenennaam. “Our data indicates the need to screen for plasmid integration when they’re used in the editing process.”

Since the original work in 2013, initiated by the Minnesota-based company Recombinetics, new methods have been developed that no longer use donor template plasmid or other extraneous DNA sequence to bring about introgression of the hornless allele.

Scientists did not observe any other unintended genomic alterations in the calves, and all animals remained healthy during the study period. Neither the bull, nor the calves, entered the food supply as per FDA guidance for genome-edited livestock.

WHY THE NEED FOR HORNLESS COWS?

Many dairy breeds naturally grow horns. But on dairy farms, the horns are typically removed, or the calves “disbudded” at a young age. Animals that don’t have horns are less likely to harm animals or dairy workers and have fewer aggressive behaviors. The dehorning process is unpleasant and has implications for animal welfare. Van Eenennaam said genome-editing offers a pain-free genetic alternative to removing horns by introducing a naturally occurring genetic variant, or allele, that is present in some breeds of beef cattle such as Angus.

Here’s a link to and a citation for the paper,

Genomic and phenotypic analyses of six offspring of a genome-edited hornless bull by Amy E. Young, Tamer A. Mansour, Bret R. McNabb, Joseph R. Owen, Josephine F. Trott, C. Titus Brown & Alison L. Van Eenennaam. Nature Biotechnology (2019) DOI: https://doi.org/10.1038/s41587-019-0266-0 Published 07 October 2019

This paper is open access.

Of puke, CRISPR, fruit flies, and monarch butterflies

I’ve never seen an educational institution use a somewhat vulgar slang term such as ‘puke’ before. Especially not in a news release. You’ll find that elsewhere online ‘puke’ has been replaced, in the headline, with the more socially acceptable ‘vomit’.

Since I wanted to catch this historic moment amid concerns that the original version of the news release will disappear, I’m including the entire news release as i saw it on EurekAlert.com (from an October 2, 2019 University of California at Berkeley news release),

News Release 2-Oct-2019

CRISPRed fruit flies mimic monarch butterfly — and could make you puke
Scientists recreate in flies the mutations that let monarch butterfly eat toxic milkweed with impunity

University of California – Berkeley

The fruit flies in Noah Whiteman’s lab may be hazardous to your health.

Whiteman and his University of California, Berkeley, colleagues have turned perfectly palatable fruit flies — palatable, at least, to frogs and birds — into potentially poisonous prey that may cause anything that eats them to puke. In large enough quantities, the flies likely would make a human puke, too, much like the emetic effect of ipecac syrup.

That’s because the team genetically engineered the flies, using CRISPR-Cas9 gene editing, to be able to eat milkweed without dying and to sequester its toxins, just as America’s most beloved butterfly, the monarch, does to deter predators.

This is the first time anyone has recreated in a multicellular organism a set of evolutionary mutations leading to a totally new adaptation to the environment — in this case, a new diet and new way of deterring predators.

Like monarch caterpillars, the CRISPRed fruit fly maggots thrive on milkweed, which contains toxins that kill most other animals, humans included. The maggots store the toxins in their bodies and retain them through metamorphosis, after they turn into adult flies, which means the adult “monarch flies” could also make animals upchuck.

The team achieved this feat by making three CRISPR edits in a single gene: modifications identical to the genetic mutations that allow monarch butterflies to dine on milkweed and sequester its poison. These mutations in the monarch have allowed it to eat common poisonous plants other insects could not and are key to the butterfly’s thriving presence throughout North and Central America.

Flies with the triple genetic mutation proved to be 1,000 times less sensitive to milkweed toxin than the wild fruit fly, Drosophila melanogaster.

Whiteman and his colleagues will describe their experiment in the Oct. 2 [2019] issue of the journal Nature.

Monarch flies

The UC Berkeley researchers created these monarch flies to establish, beyond a shadow of a doubt, which genetic changes in the genome of monarch butterflies were necessary to allow them to eat milkweed with impunity. They found, surprisingly, that only three single-nucleotide substitutions in one gene are sufficient to give fruit flies the same toxin resistance as monarchs.

“All we did was change three sites, and we made these superflies,” said Whiteman, an associate professor of integrative biology. “But to me, the most amazing thing is that we were able to test evolutionary hypotheses in a way that has never been possible outside of cell lines. It would have been difficult to discover this without having the ability to create mutations with CRISPR.”

Whiteman’s team also showed that 20 other insect groups able to eat milkweed and related toxic plants – including moths, beetles, wasps, flies, aphids, a weevil and a true bug, most of which sport the color orange to warn away predators – independently evolved mutations in one, two or three of the same amino acid positions to overcome, to varying degrees, the toxic effects of these plant poisons.

In fact, his team reconstructed the one, two or three mutations that led to each of the four butterfly and moth lineages, each mutation conferring some resistance to the toxin. All three mutations were necessary to make the monarch butterfly the king of milkweed.
Resistance to milkweed toxin comes at a cost, however. Monarch flies are not as quick to recover from upsets, such as being shaken — a test known as “bang” sensitivity.

“This shows there is a cost to mutations, in terms of recovery of the nervous system and probably other things we don’t know about,” Whiteman said. “But the benefit of being able to escape a predator is so high … if it’s death or toxins, toxins will win, even if there is a cost.”

Plant vs. insect

Whiteman is interested in the evolutionary battle between plants and parasites and was intrigued by the evolutionary adaptations that allowed the monarch to beat the milkweed’s toxic defense. He also wanted to know whether other insects that are resistant — though all less resistant than the monarch — use similar tricks to disable the toxin.

“Since plants and animals first invaded land 400 million years ago, this coevolutionary arms race is thought to have given rise to a lot of the plant and animal diversity that we see, because most animals are insects, and most insects are herbivorous: they eat plants,” he said.

Milkweeds and a variety of other plants, including foxglove, the source of digitoxin and digoxin, contain related toxins — called cardiac glycosides — that can kill an elephant and any creature with a beating heart. Foxglove’s effect on the heart is the reason that an extract of the plant, in the genus Digitalis, has been used for centuries to treat heart conditions, and why digoxin and digitoxin are used today to treat congestive heart failure.

These plants’ bitterness alone is enough to deter most animals, but a small minority of insects, including the monarch (Danaus plexippus) and its relative, the queen butterfly (Danaus gilippus), have learned to love milkweed and use it to repel predators.

Whiteman noted that the monarch is a tropical lineage that invaded North America after the last ice age, in part enabled by the three mutations that allowed it to eat a poisonous plant other animals could not, giving it a survival edge and a natural defense against predators.

“The monarch resists the toxin the best of all the insects, and it has the biggest population size of any of them; it’s all over the world,” he said.

The new paper reveals that the mutations had to occur in the right sequence, or else the flies would never have survived the three separate mutational events.

Thwarting the sodium pump

The poisons in these plants, most of them a type of cardenolide, interfere with the sodium/potassium pump (Na+/K+-ATPase) that most of the body’s cells use to move sodium ions out and potassium ions in. The pump creates an ion imbalance that the cell uses to its favor. Nerve cells, for example, transmit signals along their elongated cell bodies, or axons, by opening sodium and potassium gates in a wave that moves down the axon, allowing ions to flow in and out to equilibrate the imbalance. After the wave passes, the sodium pump re-establishes the ionic imbalance.

Digitoxin, from foxglove, and ouabain, the main toxin in milkweed, block the pump and prevent the cell from establishing the sodium/potassium gradient. This throws the ion concentration in the cell out of whack, causing all sorts of problems. In animals with hearts, like birds and humans, heart cells begin to beat so strongly that the heart fails; the result is death by cardiac arrest.

Scientists have known for decades how these toxins interact with the sodium pump: they bind the part of the pump protein that sticks out through the cell membrane, clogging the channel. They’ve even identified two specific amino acid changes or mutations in the protein pump that monarchs and the other insects evolved to prevent the toxin from binding.

But Whiteman and his colleagues weren’t satisfied with this just so explanation: that insects coincidentally developed the same two identical mutations in the sodium pump 14 separate times, end of story. With the advent of CRISPR-Cas9 gene editing in 2012, coinvented by UC Berkeley’s Jennifer Doudna, Whiteman and colleagues Anurag Agrawal of Cornell University and Susanne Dobler of the University of Hamburg in Germany applied to the Templeton Foundation for a grant to recreate these mutations in fruit flies and to see if they could make the flies immune to the toxic effects of cardenolides.

Seven years, many failed attempts and one new grant from the National Institutes of Health later, along with the dedicated CRISPR work of GenetiVision of Houston, Texas, they finally achieved their goal. In the process, they discovered a third critical, compensatory mutation in the sodium pump that had to occur before the last and most potent resistance mutation would stick. Without this compensatory mutation, the maggots died.

Their detective work required inserting single, double and triple mutations into the fruit fly’s own sodium pump gene, in various orders, to assess which ones were necessary. Insects having only one of the two known amino acid changes in the sodium pump gene were best at resisting the plant poisons, but they also had serious side effects — nervous system problems — consistent with the fact that sodium pump mutations in humans are often associated with seizures. However, the third, compensatory mutation somehow reduces the negative effects of the other two mutations.

“One substitution that evolved confers weak resistance, but it is always present and allows for substitutions that are going to confer the most resistance,” said postdoctoral fellow Marianna Karageorgi, a geneticist and evolutionary biologist. “This substitution in the insect unlocks the resistance substitutions, reducing the neurological costs of resistance. Because this trait has evolved so many times, we have also shown that this is not random.”

The fact that one compensatory mutation is required before insects with the most resistant mutation could survive placed a constraint on how insects could evolve toxin resistance, explaining why all 21 lineages converged on the same solution, Whiteman said. In other situations, such as where the protein involved is not so critical to survival, animals might find different solutions.

“This helps answer the question, ‘Why does convergence evolve sometimes, but not other times?'” Whiteman said. “Maybe the constraints vary. That’s a simple answer, but if you think about it, these three mutations turned a Drosophila protein into a monarch one, with respect to cardenolide resistance. That’s kind of remarkable.”

###

The research was funded by the Templeton Foundation and the National Institutes of Health. Co-authors with Whiteman and Agrawal are co-first authors Marianthi Karageorgi of UC Berkeley and Simon Groen, now at New York University; Fidan Sumbul and Felix Rico of Aix-Marseille Université in France; Julianne Pelaez, Kirsten Verster, Jessica Aguilar, Susan Bernstein, Teruyuki Matsunaga and Michael Astourian of UC Berkeley; Amy Hastings of Cornell; and Susanne Dobler of Universität Hamburg in Germany.

Robert Sanders’ Oct. 2, 2019′ news release for the University of California at Berkeley (it’s also been republished as an Oct. 2, 2019 news item on ScienceDaily) has had its headline changed to ‘vomit’ but you’ll find the more vulgar word remains in two locations of the second paragraph of the revised new release.

If you have time, go to the news release on the University of California at Berkeley website just to admire the images that have been embedded in the news release. Here’s one,

Caption: A Drosophila melanogaster “monarch fly” with mutations introduced by CRISPR-Cas9 genome editing (V111, S119 and H122) to the sodium potassium pump, on a wing of a monarch butterfly (Danaus plexippus). Credit & Ccpyright: Julianne Pelaez

Here’s a link to and a citation for the paper,

Genome editing retraces the evolution of toxin resistance in the monarch butterfly by Marianthi Karageorgi, Simon C. Groen, Fidan Sumbul, Julianne N. Pelaez, Kirsten I. Verster, Jessica M. Aguilar, Amy P. Hastings, Susan L. Bernstein, Teruyuki Matsunaga, Michael Astourian, Geno Guerra, Felix Rico, Susanne Dobler, Anurag A. Agrawal & Noah K. Whiteman. Nature (2019) DOI: https://doi.org/10.1038/s41586-019-1610-8 Published 02 October 2019

This paper is behind a paywall.

Words about a word

I’m glad they changed the headline and substituted vomit for puke. I think we need vulgar and/or taboo words to release anger or disgust or other difficult emotions. Incorporating those words into standard language deprives them of that power.

The last word: Genetivision

The company mentioned in the new release, Genetivision, is the place to go for transgenic flies. Here’s a sampling from the their Testimonials webpage,

GenetiVision‘s service has been excellent in the quality and price. The timeliness of its international service has been a big plus. We are very happy with its consistent service and the flies it generates.”
Kwang-Wook Choi, Ph.D.
Department of Biological Sciences
Korea Advanced Institute of Science and Technology


“We couldn’t be happier with GenetiVision. Great prices on both standard P and PhiC31 transgenics, quick turnaround time, and we’re still batting 1000 with transformant success. We used to do our own injections but your service makes it both faster and more cost-effective. Thanks for your service!”
Thomas Neufeld, Ph.D.
Department of Genetics, Cell Biology and Development
University of Minnesota

You can find out more here at the Genetivision website.

CRISPR [clustered regularly interspaced short palindromic repeats) has a metaphor issue?

Elinor Hortie at the University of Sydney (Australia) has written a very interesting essay about CRISPR ‘scissors’, a metaphor she find misleading. From Hortie’s July 4, 2019 essay on The Conversation,

Last week I read an article about CRISPR, the latest tool scientists are using to edit DNA. It was a great piece – well researched, beautifully written, factually accurate. It covered some of the amazing projects scientist are working on using CRISPR, like bringing animals back from extinction and curing diseases. It also gave me the heebies, but not for the reason you might expect.

Take CRISPR. It’s most often described as a pair of molecular scissors that can be used to modify DNA, the blueprint for life. And when we read that, I think most of us start imagining something like a child with her Lego bricks strewn in front of her, instruction booklet in one hand, scissors in the other. One set of pictograms, one model; one gene, one disease; one snip, one cure. We’re there in a blink. CRISPR seems like it can work miracles.

I want to stress that the molecular scissors metaphor is pretty damn accurate as far as it goes. But in focusing on the relatively simple relationship between CRISPR and DNA, we miss the far more complicated relationship between DNA and the rest of the body. This metaphor ignores an entire ecosystem of moving parts that are crucial for understanding the awe-inspiring, absolutely insane thing scientists are trying to do when they attempt gene editing.

Hortie proposes a different metaphor,

In my research I use CRISPR from time to time. To design experiments and interpret results effectively, I need a solid way to conceptualise what it can (and can’t) do. I do not think of CRISPR as molecular scissors.

Instead I imagine a city. The greater metropolis represents the body, the suburbs are organs, the buildings are cells, the people are proteins, and the internet is DNA.

In this metaphor CRISPR is malware. More precisely, CRISPR is malware that can search for any chosen 20-character line of code and corrupt it. This is not a perfect metaphor by any stretch, but it gets me closer to understanding than almost anything else.

Hortie offers an example from her own work demonstrating how a CRISPR ‘malware’ metaphor/analogy more accurately represents the experience of using the gene-editing system,

As an example, let’s look at Alzheimer’s, one of the diseases CRISPR is being touted to cure. The headlines are usually some variation of “CRISPR to correct Alzheimer’s gene!”, and the molecular scissors analogy is never far behind.

It seems reasonable to me that someone could read those words and assume that chopping away the disease-gene with the DNA-shears should be relatively simple. When the cure doesn’t appear within five years, I can understand why that same person would come to ask me why Big Pharma is holding out (this has happened to me more than once).

Now let’s see how it looks using the malware metaphor. The consensus is that Alzheimer’s manifests when a specific protein goes rogue, causing damage to cells and thereby stopping things from working properly inside the brain. It might have a genetic cause, but it’s complicated. In our allegorical city, what would that look like?

I think riots would come close. Rampaging humans (proteins) destroying houses and property (cells), thereby seriously derailing the normal functioning of a specific suburb (the brain).

And you want to fix that with malware?

It’s hard to predict the domino effect

Can you imagine for a second trying to stop soccer hooligans smashing things on the streets of Buenos Aires by corrupting roughly three words in the FIFA by-laws with what’s essentially a jazzed-up command-F function?

I’m not saying it’s not possible – it absolutely is.

But think of all the prior knowledge you need, and all the pieces that have to fall in place for that to work. You’d have to know that the riots are caused by football fans. You’d have to understand which rule was bothering them (heaven help you if it’s more than one), and if that rule causes drama at every game. You’d have to find a 20-character phrase that, when corrupted, would change how the rule was read, rather than just making a trivial typo.

You’d have to know that the relevant footballers have access to the updated rule book, and you’d have to know there were no other regulations making your chosen rule redundant. You’d have to know there aren’t any similar 20-character phrases anywhere on the internet that might get corrupted at the same time (like in the rules for presidential succession say, or in the nuclear warhead codes). Even then you’d still be rolling the dice.

Even if you stop the riots successfully, which of us really know the long-term consequences of changing the World Game forever?

That’s stretching the metaphor as Hortie notes herself later in the essay. And, she’s not the only one concerned about metaphors and CRISPR. There’s a December 8, 0217 article by Rebecca Robbins for STAT news which covers ten analogies/metaphors ranked from worst to best,

… Some of these analogies are better than others. To compile the definitive ranking, I sat down with STAT’s senior science writer Sharon Begley, a wordsmith who has herself compared CRISPR to “1,000 monkeys editing a Word document” and the kind of dog “you can train to retrieve everything from Frisbees to slippers to a cold beer.”

Sharon and I evaluated each of the metaphors we found by considering these three questions: Is it creative? Is it clear? And is it accurate? Below, our rankings of CRISPR analogies, ordered from worst to best:

0. A knockout punch


9. The hand of God


8. A bomb removal squad

It’s a very interesting list with a description of why each does and doesn’t work as an analogy. By the way, ‘scissors’ was not the top analogy. The number one spot went to ‘A Swiss army knife’.

There are many more essays than I would have believed concerning CRISPR and metaphors/analogies. I’m glad to see them as the language we use to describe our work and our world helps us understand it and can constrain us in unexpected ways. Critiques such as Hortie’s and the others can help us to refine the language and to recognize its limitations.

h/t July 4, 2019 news item on phys.org

Gold nanoparticle loaded with CRISPR used to edit genes

CRISPR (clustered regularly interspaced short palindromic repeats) gene editing is usually paired with a virus (9, 12a, etc.) but this time scientists are using a gold nanoparticle. From a May 27, 2019 news item on Nanowerk (Note: Links have been removed),

Scientists at Fred Hutchinson Cancer Research Center took a step toward making gene therapy more practical by simplifying the way gene-editing instructions are delivered to cells. Using a gold nanoparticle instead of an inactivated virus, they safely delivered gene-editing tools in lab models of HIV and inherited blood disorders, as reported in Nature Materials (“Targeted homology-directed repair in blood stem and progenitor cells with CRISPR nanoformulations”).

A May 27, 2019 Fred Hutchinson Cancer Research Center news release (also on EurekAlert) by Jake Siegel, which originated the news item, expands on the theme, provides more detail,

It’s the first time that a gold nanoparticle loaded with CRISPR has been used to edit genes in a rare but powerful subset of blood stem cells, the source of all blood cells. The CRISPR-carrying gold nanoparticle led to successful gene editing in blood stem cells with no toxic effects.

“As gene therapies make their way through clinical trials and become available to patients, we need a more practical approach,” said senior author Dr. Jennifer Adair, an assistant member of the Clinical Research Division at Fred Hutch, adding that current methods of performing gene therapy are inaccessible to millions of people around the world. “I wanted to find something simpler, something that would passively deliver gene editing to blood stem cells.”

While CRISPR has made it faster and easier to precisely deliver genetic modifications to the genome, it still has challenges. Getting cells to accept CRISPR gene-editing tools involves a small electric shock that can damage and even kill the cells. And if precise gene edits are required, then additional molecules must be engineered to deliver them –adding cost and time.

Gold nanoparticles are a promising alternative because the surface of these tiny spheres (around 1 billionth the size of a grain of table salt) allows other molecules to easily stick to them and stay adhered.

“We engineered the gold nanoparticles to quickly cross the cell membrane, dodge cell organelles that seek to destroy them and go right to the cell nucleus to edit genes,” said Dr. Reza Shahbazi, a Fred Hutch postdoctoral researcher who has worked with gold nanoparticles for drug and gene delivery for seven years.

Shahbazi made the gold particles from laboratory-grade gold that is purified and comes as a liquid in a small lab bottle. He mixed the purified gold into a solution that causes the individual gold ions to form tiny particles, which the researchers then measured for size.

They found that a particular size – 19 nanometers wide – was the best for being big and sticky enough to add gene-editing materials to the surface of the particles, while still being small enough for cells to absorb them.

Packed onto the gold particles, the Fred Hutch team added these gene-editing components (diagram available [see below]):

A type of molecular guide called crRNA acts as a genetic GPS to show the CRISPR complex where in the genome to make the cut.

CRISPR nuclease protein, often called “genetic scissors,” makes the cut in the DNA. The CRISPR nuclease protein most often used is Cas9. But the Fred Hutch researchers also studied Cas12a (formerly called Cpf1) because Cas12a makes a staggered cut in DNA. The researchers hoped this would allow the cells to more efficiently repair the cut and while so doing embed the new genetic instructions into the cell. Another advantage of Cas12a over Cas9 is that it only requires one molecular guide, which is important because of space constraints on the nanoparticles. Cas9 requires two molecular guides.

Instructions for what genetic changes to make (“ssDNA”). The Fred Hutch team chose two inherited genetic changes that bestow protection from disease: CCR5, which protects against HIV, and gamma hemoglobin, which protects against blood disorders such as sickle cell disease and thalassemia.

A coating of a polyethylenimine swarms the surface of the particles to give them a more positive charge, which enables them to more readily be absorbed into cells. This is an improvement over another method of getting cells to take up gene editing tools, called electroporation, which involves lightly shocking the cells to get them to open and allow the genetic instructions to enter.

Then the researchers isolated blood stem cells with a protein marker on their surface called CD34. These CD34-positive cells contain the blood-making progenitor cells that give rise to the entire blood and immune system.

“These cells replenish blood in the body every day, making them a good candidate for one-time gene therapy because it will last a lifetime as the cells replace themselves,” Adair said.

Observing human blood stem cells in a lab dish, the researchers found that their fully loaded gold nanoparticles were taken up naturally by cells within six hours of being added and within 24 to 48 hours they could see gene editing happening. They observed that the Cas12a CRISPR protein partner was better at delivering very precise genetic edits to the cells than the more commonly used cas9 protein partner.

The gene-editing effect reached a peak eight weeks after the researchers injected the cells into mouse models; 22 weeks after injection the edited cells were still there. The Fred Hutch researchers also found edited cells in the bone marrow, spleen and thymus of the mouse models, a sign that the dividing blood cells in those organs could carry on the treatment without the mice having to be treated again.

“We believe we have a good candidate for two diseases — HIV and hemoglobinopathies — though we are also evaluating other disease targets where small genetic changes can have a big impact, as well as ways to make bigger genetic changes,” Adair said. “The next step is to increase how much gene editing happens in each cell, which is definitely doable. That will make it closer to being an effective therapy.”

In the study, the researchers report 10 to 20 percent of cells took on the gene edits, which is a promising start, but the researchers would like to aim for 50% or more of the cells being edited, which they believe will have a good chance of combatting these diseases.

###

Adair and Shahbazi are looking for commercial partners to develop the technology into therapies for people. They hope to begin clinical trials within a few years.

Here’s the diagram of a gold nanoparticle loaded with CRISPR,

Caption: Graphic of a fully loaded gold nanoparticle with CRISPR and other gene editing tools. Credit: Image courtesy of the Adair lab at Fred Hutch.

Here’s a link to and a citation for the paper,

Targeted homology-directed repair in blood stem and progenitor cells with CRISPR nanoformulations by Reza Shahbazi, Gabriella Sghia-Hughes, Jack L. Reid, Sara Kubek, Kevin G. Haworth, Olivier Humbert, Hans-Peter Kiem & Jennifer E. Adair. Nature Materials (2019) DOI https://doi.org/10.1038/s41563-019-0385-5Published 27 May 2019

This paper is behind a paywall.