CRISPR and editing the germline in the US (part 1 of 3): In the beginning

There’s been a minor flurry of interest in CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats; also known as CRISPR-CAS9), a gene-editing technique, since a team in Oregon announced a paper describing their work editing the germline. Since I’ve been following the CRISPR-CAS9 story for a while this seems like a good juncture for a more in-depth look at the topic. In this first part I’m including an introduction to CRISPR, some information about the latest US work, and some previous writing about ethics issues raised when Chinese scientists first announced their work editing germlines in 2015 and during the patent dispute between the University of California at Berkeley and Harvard University’s Broad Institute.

Introduction to CRISPR

I’ve been searching for a good description of CRISPR and this helped to clear up some questions for me (Thank you to MIT Review),

For anyone who’s been reading about science for a while, this upbeat approach to explaining how a particular technology will solve all sorts of problems will seem quite familiar. It’s not the most hyperbolic piece I’ve seen but it barely mentions any problems associated with research (for some of the problems see: ‘The interest flurry’ later in part 2).

Oregon team

Steve Connor’s July 26, 2017 article for the MIT (Massachusetts Institute of Technology) Technology Review breaks the news (Note: Links have been removed),

The first known attempt at creating genetically modified human embryos in the United States has been carried out by a team of researchers in Portland, Oregon, MIT Technology Review has learned.

The effort, led by Shoukhrat Mitalipov of Oregon Health and Science University, involved changing the DNA of a large number of one-cell embryos with the gene-editing technique CRISPR, according to people familiar with the scientific results.

Until now, American scientists have watched with a combination of awe, envy, and some alarm as scientists elsewhere were first to explore the controversial practice. To date, three previous reports of editing human embryos were all published by scientists in China.

Now Mitalipov is believed to have broken new ground both in the number of embryos experimented upon and by demonstrating that it is possible to safely and efficiently correct defective genes that cause inherited diseases.

Although none of the embryos were allowed to develop for more than a few days—and there was never any intention of implanting them into a womb—the experiments are a milestone on what may prove to be an inevitable journey toward the birth of the first genetically modified humans.

In altering the DNA code of human embryos, the objective of scientists is to show that they can eradicate or correct genes that cause inherited disease, like the blood condition beta-thalassemia. The process is termed “germline engineering” because any genetically modified child would then pass the changes on to subsequent generations via their own germ cells—the egg and sperm.

Some critics say germline experiments could open the floodgates to a brave new world of “designer babies” engineered with genetic enhancements—a prospect bitterly opposed by a range of religious organizations, civil society groups, and biotech companies.

The U.S. intelligence community last year called CRISPR a potential “weapon of mass destruction.”

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

Correction of a pathogenic gene mutation in human embryos by Hong Ma, Nuria Marti-Gutierrez, Sang-Wook Park, Jun Wu, Yeonmi Lee, Keiichiro Suzuki, Amy Koski, Dongmei Ji, Tomonari Hayama, Riffat Ahmed, Hayley Darby, Crystal Van Dyken, Ying Li, Eunju Kang, A.-Reum Park, Daesik Kim, Sang-Tae Kim, Jianhui Gong, Ying Gu, Xun Xu, David Battaglia, Sacha A. Krieg, David M. Lee, Diana H. Wu, Don P. Wolf, Stephen B. Heitner, Juan Carlos Izpisua Belmonte, Paula Amato, Jin-Soo Kim, Sanjiv Kaul, & Shoukhrat Mitalipov. Nature (2017) doi:10.1038/nature23305 Published online 02 August 2017

This paper appears to be open access.

CRISPR Issues: ethics and patents

In my May 14, 2015 posting I mentioned a ‘moratorium’ on germline research, the Chinese research paper, and the stance taken by the US National Institutes of Health (NIH),

The CRISPR technology has reignited a discussion about ethical and moral issues of human genetic engineering some of which is reviewed in an April 7, 2015 posting about a moratorium by Sheila Jasanoff, J. Benjamin Hurlbut and Krishanu Saha for the Guardian science blogs (Note: A link has been removed),

On April 3, 2015, a group of prominent biologists and ethicists writing in Science called for a moratorium on germline gene engineering; modifications to the human genome that will be passed on to future generations. The moratorium would apply to a technology called CRISPR/Cas9, which enables the removal of undesirable genes, insertion of desirable ones, and the broad recoding of nearly any DNA sequence.

Such modifications could affect every cell in an adult human being, including germ cells, and therefore be passed down through the generations. Many organisms across the range of biological complexity have already been edited in this way to generate designer bacteria, plants and primates. There is little reason to believe the same could not be done with human eggs, sperm and embryos. Now that the technology to engineer human germlines is here, the advocates for a moratorium declared, it is time to chart a prudent path forward. They recommend four actions: a hold on clinical applications; creation of expert forums; transparent research; and a globally representative group to recommend policy approaches.

The authors go on to review precedents and reasons for the moratorium while suggesting we need better ways for citizens to engage with and debate these issues,

An effective moratorium must be grounded in the principle that the power to modify the human genome demands serious engagement not only from scientists and ethicists but from all citizens. We need a more complex architecture for public deliberation, built on the recognition that we, as citizens, have a duty to participate in shaping our biotechnological futures, just as governments have a duty to empower us to participate in that process. Decisions such as whether or not to edit human genes should not be left to elite and invisible experts, whether in universities, ad hoc commissions, or parliamentary advisory committees. Nor should public deliberation be temporally limited by the span of a moratorium or narrowed to topics that experts deem reasonable to debate.

I recommend reading the post in its entirety as there are nuances that are best appreciated in the entirety of the piece.

Shortly after this essay was published, Chinese scientists announced they had genetically modified (nonviable) human embryos. From an April 22, 2015 article by David Cyranoski and Sara Reardon in Nature where the research and some of the ethical issues discussed,

In a world first, Chinese scientists have reported editing the genomes of human embryos. The results are published1 in the online journal Protein & Cell and confirm widespread rumours that such experiments had been conducted — rumours that sparked a high-profile debate last month2, 3 about the ethical implications of such work.

In the paper, researchers led by Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou, tried to head off such concerns by using ‘non-viable’ embryos, which cannot result in a live birth, that were obtained from local fertility clinics. The team attempted to modify the gene responsible for β-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. The researchers say that their results reveal serious obstacles to using the method in medical applications.

“I believe this is the first report of CRISPR/Cas9 applied to human pre-implantation embryos and as such the study is a landmark, as well as a cautionary tale,” says George Daley, a stem-cell biologist at Harvard Medical School in Boston, Massachusetts. “Their study should be a stern warning to any practitioner who thinks the technology is ready for testing to eradicate disease genes.”

….

Huang says that the paper was rejected by Nature and Science, in part because of ethical objections; both journals declined to comment on the claim. (Nature’s news team is editorially independent of its research editorial team.)

He adds that critics of the paper have noted that the low efficiencies and high number of off-target mutations could be specific to the abnormal embryos used in the study. Huang acknowledges the critique, but because there are no examples of gene editing in normal embryos he says that there is no way to know if the technique operates differently in them.

Still, he maintains that the embryos allow for a more meaningful model — and one closer to a normal human embryo — than an animal model or one using adult human cells. “We wanted to show our data to the world so people know what really happened with this model, rather than just talking about what would happen without data,” he says.

This, too, is a good and thoughtful read.

There was an official response in the US to the publication of this research, from an April 29, 2015 post by David Bruggeman on his Pasco Phronesis blog (Note: Links have been removed),

In light of Chinese researchers reporting their efforts to edit the genes of ‘non-viable’ human embryos, the National Institutes of Health (NIH) Director Francis Collins issued a statement (H/T Carl Zimmer).

“NIH will not fund any use of gene-editing technologies in human embryos. The concept of altering the human germline in embryos for clinical purposes has been debated over many years from many different perspectives, and has been viewed almost universally as a line that should not be crossed. Advances in technology have given us an elegant new way of carrying out genome editing, but the strong arguments against engaging in this activity remain. These include the serious and unquantifiable safety issues, ethical issues presented by altering the germline in a way that affects the next generation without their consent, and a current lack of compelling medical applications justifying the use of CRISPR/Cas9 in embryos.” …

The US has modified its stance according to a February 14, 2017 article by Jocelyn Kaiser for Science Magazine (Note: Links have been removed),

Editing the DNA of a human embryo to prevent a disease in a baby could be ethically allowable one day—but only in rare circumstances and with safeguards in place, says a widely anticipated report released today.

The report from an international committee convened by the U.S. National Academy of Sciences (NAS) and the National Academy of Medicine in Washington, D.C., concludes that such a clinical trial “might be permitted, but only following much more research” on risks and benefits, and “only for compelling reasons and under strict oversight.” Those situations could be limited to couples who both have a serious genetic disease and for whom embryo editing is “really the last reasonable option” if they want to have a healthy biological child, says committee co-chair Alta Charo, a bioethicist at the University of Wisconsin in Madison.

Some researchers are pleased with the report, saying it is consistent with previous conclusions that safely altering the DNA of human eggs, sperm, or early embryos—known as germline editing—to create a baby could be possible eventually. “They have closed the door to the vast majority of germline applications and left it open for a very small, well-defined subset. That’s not unreasonable in my opinion,” says genome researcher Eric Lander of the Broad Institute in Cambridge, Massachusetts. Lander was among the organizers of an international summit at NAS in December 2015 who called for more discussion before proceeding with embryo editing.

But others see the report as lowering the bar for such experiments because it does not explicitly say they should be prohibited for now. “It changes the tone to an affirmative position in the absence of the broad public debate this report calls for,” says Edward Lanphier, chairman of the DNA editing company Sangamo Therapeutics in Richmond, California. Two years ago, he co-authored a Nature commentary calling for a moratorium on clinical embryo editing.

One advocacy group opposed to embryo editing goes further. “We’re very disappointed with the report. It’s really a pretty dramatic shift from the existing and widespread agreement globally that human germline editing should be prohibited,” says Marcy Darnovsky, executive director of the Center for Genetics and Society in Berkeley, California.

Interestingly, this change of stance occurred just prior to a CRISPR patent decision (from my March 15, 2017 posting),

I have written about the CRISPR patent tussle (Harvard & MIT’s [Massachusetts Institute of Technology] Broad Institute vs the University of California at Berkeley) previously in a Jan. 6, 2015 posting and in a more detailed May 14, 2015 posting. I also mentioned (in a Jan. 17, 2017 posting) CRISPR and its patent issues in the context of a posting about a Slate.com series on Frankenstein and the novel’s applicability to our own time. This patent fight is being bitterly fought as fortunes are at stake.

It seems a decision has been made regarding the CRISPR patent claims. From a Feb. 17, 2017 article by Charmaine Distor for The Science Times,

After an intense court battle, the US Patent and Trademark Office (USPTO) released its ruling on February 15 [2017]. The rights for the CRISPR-Cas9 gene editing technology was handed over to the Broad Institute of Harvard University and the Massachusetts Institute of Technology (MIT).

According to an article in Nature, the said court battle was between the Broad Institute and the University of California. The two institutions are fighting over the intellectual property right for the CRISPR patent. The case between the two started when the patent was first awarded to the Broad Institute despite having the University of California apply first for the CRISPR patent.

Heidi Ledford’s Feb. 17, 2017 article for Nature provides more insight into the situation (Note: Links have been removed),

It [USPTO] ruled that the Broad Institute of Harvard and MIT in Cambridge could keep its patents on using CRISPR–Cas9 in eukaryotic cells. That was a blow to the University of California in Berkeley, which had filed its own patents and had hoped to have the Broad’s thrown out.

The fight goes back to 2012, when Jennifer Doudna at Berkeley, Emmanuelle Charpentier, then at the University of Vienna, and their colleagues outlined how CRISPR–Cas9 could be used to precisely cut isolated DNA1. In 2013, Feng Zhang at the Broad and his colleagues — and other teams — showed2 how it could be adapted to edit DNA in eukaryotic cells such as plants, livestock and humans.

Berkeley filed for a patent earlier, but the USPTO granted the Broad’s patents first — and this week upheld them. There are high stakes involved in the ruling. The holder of key patents could make millions of dollars from CRISPR–Cas9’s applications in industry: already, the technique has sped up genetic research, and scientists are using it to develop disease-resistant livestock and treatments for human diseases.

….

I also noted this eyebrow-lifting statistic,  “As for Ledford’s 3rd point, there are an estimated 763 patent families (groups of related patents) claiming CAS9 leading to the distinct possibility that the Broad Institute will be fighting many patent claims in the future.)

-30-

Part 2 covers three critical responses to the reporting and between them describe the technology in more detail and the possibility of ‘designer babies’.  CRISPR and editing the germline in the US (part 2 of 3): ‘designer babies’?

Part 3 is all about public discussion or, rather, the lack of and need for according to a couple of social scientists. Informally, there is some discussion via pop culture and Joelle Renstrom notes although she is focused on the larger issues touched on by the television series, Orphan Black and as I touch on in my final comments. CRISPR and editing the germline in the US (part 3 of 3): public discussions and pop culture

Leave a Reply

Your email address will not be published. Required fields are marked *