Tag Archives: gene editing

Gene editing to identify and change parts of chicken DNA and limit the spread of bird flu virus

This news comes from the University of Edinburgh (Scotland). From an October 10, 2023 news item on phys.org, Note: A link has been removed,

Scientists have used gene editing techniques to identify and change parts of chicken DNA that could limit the spread of the bird flu virus in the animals.

Researchers were able to restrict—but not completely block—the virus from infecting chickens by altering a small section of their DNA.

The birds showed no signs that the change in their DNA had any impact on their health or well-being.

The findings are an encouraging step forward, but experts highlight that further gene edits would be needed to produce a chicken population which cannot be infected by bird flu—one of the world’s most costly animal diseases.

An October 10, 2023 University of Edinburgh press release, which originated the news item, provides more detail about this research,

Gene editing

Scientists from University of Edinburgh, Imperial College London and the Pirbright Institute bred the chickens using gene editing techniques to alter the section of DNA responsible for producing the protein ANP32A. During an infection, flu viruses hijack this molecule to help replicate themselves.

When the ANP32A gene-edited chickens were exposed to a normal dose of the H9N2-UDL strain of avian influenza virus – commonly known as bird flu – 9 out of 10 birds remained uninfected and there was no spread to other chickens.

Partial protection

The research team then exposed the gene-edited birds to an artificially high dose of avian influenza virus to further test their resilience.

When exposed to the high dose, half of the group – 5 out of 10 birds – became infected. However, the gene edit did provide some protection, with the amount of virus in the infected gene-edited chickens much lower than the level typically seen during infection in non-gene-edited chickens.

The gene edit also helped to limit onward spread of the virus to just one of four non-gene-edited chickens placed in the same incubator. There was no transmission to gene-edited birds.

Viral evolution

Scientists found that in the ANP32A gene-edited birds, the virus had adapted to enlist the support of two related proteins – ANP32B and ANP32E – to replicate.

Following lab tests, scientists found that some of the mutations enabled the virus to utilise the human version of ANP32, but its replication remained low in cell cultures from the human airway.

Experts say that additional genetic changes would be needed for the virus to infect and spread effectively in humans.

However, the findings demonstrate that the single ANP32A gene edit is not robust enough for application in the production of chickens, according to the team.

Gene editing

Scientists from University of Edinburgh, Imperial College London and the Pirbright Institute bred the chickens using gene editing techniques to alter the section of DNA responsible for producing the protein ANP32A. During an infection, flu viruses hijack this molecule to help replicate themselves.

When the ANP32A gene-edited chickens were exposed to a normal dose of the H9N2-UDL strain of avian influenza virus – commonly known as bird flu – 9 out of 10 birds remained uninfected and there was no spread to other chickens.

Partial protection

The research team then exposed the gene-edited birds to an artificially high dose of avian influenza virus to further test their resilience.

When exposed to the high dose, half of the group – 5 out of 10 birds – became infected. However, the gene edit did provide some protection, with the amount of virus in the infected gene-edited chickens much lower than the level typically seen during infection in non-gene-edited chickens.

The gene edit also helped to limit onward spread of the virus to just one of four non-gene-edited chickens placed in the same incubator. There was no transmission to gene-edited birds.

Viral evolution

Scientists found that in the ANP32A gene-edited birds, the virus had adapted to enlist the support of two related proteins – ANP32B and ANP32E – to replicate.

Following lab tests, scientists found that some of the mutations enabled the virus to utilise the human version of ANP32, but its replication remained low in cell cultures from the human airway.

Experts say that additional genetic changes would be needed for the virus to infect and spread effectively in humans.

However, the findings demonstrate that the single ANP32A gene edit is not robust enough for application in the production of chickens, according to the team.

Further edits

To prevent the emergence of escape viruses – viruses that adapt to evade the gene edit and cause infection – the research team next targeted additional sections of DNA responsible for producing all three proteins – ANP32A, ANP32B and ANP32E – inside lab-grown chicken cells.

In cell cultures in the lab, growth of the virus was successfully blocked in cells with the three gene edits.

The next step will be to try to develop chickens with edits to all three genes. No birds have been produced yet.

The study highlights the importance of responsible gene editing and the need to be alert to the risks of driving viral evolution in unwanted directions if complete resistance is not achieved, experts say.

Bird flu is a major global threat, with a devastating impact in both farmed and wild bird populations. In the UK alone, the current outbreak of H5N1 bird flu has decimated seabird populations and cost the poultry industry more than £100 million in losses.

In rare instances, mutations in the bird flu virus allow it to infect people and cause serious illness. Efforts to control the spread of the disease are urgently needed.

“Bird flu is a great threat to bird populations. Vaccination against the virus poses a number of challenges, with significant practical and cost issues associated with vaccine deployment. Gene-editing offers a promising route towards permanent disease resistance, which could be passed down through generations, protecting poultry and reducing the risks to humans and wild birds. Our work shows that stopping the spread of avian influenza in chickens will need several simultaneous genetic changes.” Professor Mike McGrew, The study’s principal investigator, from the University of Edinburgh’s Roslin Institute

“This work is an exciting collaboration that fuses our expertise in virology with the world-leading genetic capability at the Roslin Institute. Although we haven’t yet got the perfect combination of gene edits to take this approach into the field, the results have told us a lot about how influenza virus functions inside the infected cell and how to slow its replication.” Professor Wendy Barclay, Imperial College London

The research was funded by UKRI-BBSRC, which also provides strategic funding to The Roslin Institute, and was supported by Edinburgh Innovations, the University’s commercialisation service.

Ryan O’Hare’s October 10, 2023 Imperial College London (ICL) press release offers a slightly different perspective on the same work, Note: A link has been removed,

Scientists have successfully used gene editing techniques to limit the spread of bird flu in chickens.

In a UK first, researchers have been able to restrict, but not completely block, the avian influenza virus from infecting the birds by precisely altering a small section of their DNA.

The modified birds showed no signs that the change had any impact on the animals’ health or well-being.

But the researchers say that while the findings are encouraging, further gene edits would be needed to produce chickens which cannot be infected by bird flu.

The study, carried out by researchers from the University of Edinburgh, Imperial College London and the Pirbright Institute, is published in the journal Nature Communications.

Professor Wendy Barclay, Head of the Department of Infectious Disease at Imperial College London, said: “This work is an exciting collaboration that fuses our expertise in virology with the world world-leading genetic capability at the Roslin Institute.

“Although we haven’t yet got the perfect combination of gene edits to take this approach into the field, the results have told us a lot about how influenza virus functions inside the infected cell and how to slow its replication.”

Global Threat

Bird flu is a major global threat, with a devastating impact in both farmed and wild bird populations. In the UK alone, the current outbreak of H5N1 bird flu has decimated seabird populations and cost the poultry industry more than £100 million in losses.

In the latest study, researchers aimed to test whether precise edits to the chicken’s genome could potentially generate birds which are resistant to the virus.

The team bred chickens with small edits to a gene called ANP32A. During an infection, influenza viruses hijack the ANP32A protein to help replicate themselves.

But when the gene-edited birds were exposed to a normal dose of virus (the H9N2 strain of avian influenza), 9 out of 10 birds remained uninfected and there was no spread to other chickens.

When the birds were exposed to an artificially high dose of virus, only half of them became infected. The single gene edit also provided some protection against transmission, with a much lower amount of virus in infected gene-edited birds compared to non-edited birds.

In addition, the edit also helped to limit onward spread of the virus to just one of four non-edited chickens placed in the same incubator. There was no transmission to gene-edited birds.

Triple edits

Analysis revealed that in the edited birds, the virus adapted to enlist the support of two related proteins to replicate – ANP32B and ANP32E.

Following lab tests, the researchers found some of the mutations may enable the virus to utilise the human version of ANP32, but replication remained low in cell cultures from the human airway. The researchers stress that additional genetic changes would be needed for the virus to have the potential to infect and spread effectively in humans.

According to the team, the findings demonstrate that a single gene edit is not robust enough to produce resistant chickens. To prevent the emergence of viruses able to adapt to the single edit, the team next used a triple edit to target additional proteins (ANP32A, ANP32B and ANP32E) in lab-grown chicken cells.

In cell cultures in the lab, growth of the virus was successfully blocked in cells with edits to all three genes. In future, researchers hope to develop chickens with this triple edit, but no birds have been produced at this stage.

According to the researchers, the study highlights the importance of responsible gene editing and the need to be alert to the risks of driving viral evolution in unwanted directions if complete resistance is not achieved, experts say.

Professor Mike McGrew, from the University of Edinburgh’s Roslin Institute and principal investigator of the study, said: “Bird flu is a great threat to bird populations. Vaccination against the virus poses a number of challenges, with significant practical and cost issues associated with vaccine deployment.

“Gene-editing offers a promising route towards permanent disease resistance, which could be passed down through generations, protecting poultry and reducing the risks to humans and wild birds. Our work shows that stopping the spread of avian influenza in chickens will need several simultaneous genetic changes.”

A non-gene-edited chicken (left) pictured next to an ANP32A gene-edited chicken (right). Image credit: Norrie Russell Courtesy: University of Edinburgh

There’s also an October 10, 2023 article by Jon Cohen for Science.org, which gives some idea of how much work it took to get to this point, Note: Links have been removed,

For 3 decades, Helen Sang has tinkered with the genomes of chickens to try to make the birds resistant to the flu viruses that periodically devastate flocks and raise fears of a human pandemic. Now, as an especially virulent strain of avian influenza sweeps through poultry and wild birds around the world, the geneticist at the University of Edinburgh’s Roslin Institute has her first solid success. Using the CRISPR gene editor and recent findings about what makes poultry vulnerable to flu, Sang and colleagues from three other institutions have created chickens that can resist real-life doses of avian flu viruses. “Sticking to it gets you somewhere in the end,” she says.

The result, published today [October 5, 2023] in Nature Communications, is “a long-awaited achievement,” says Jiří Hejnar, a virologist at the Czech Academy of Sciences’s Institute of Molecular Genetics whose group showed in 2020 that CRISPR-edited chickens could resist a cancer-causing virus. But farmers won’t be raising flu-proof chickens anytime soon. The edited birds still became infected when exposed to larger amounts of the flu virus. And the strategy raises a safety concern: chickens edited this way could, in theory, drive the evolution of flu variants better at infecting people. “What this showed is a proof of concept,” says Wendy Barclay, a virologist at Imperial College London who worked on the new study. “But we’re not there yet.”

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

Creating resistance to avian influenza infection through genome editing of the ANP32 gene family by Alewo Idoko-Akoh, Daniel H. Goldhill, Carol M. Sheppard, Dagmara Bialy, Jessica L. Quantrill, Ksenia Sukhova, Jonathan C. Brown, Samuel Richardson, Ciara Campbell, Lorna Taylor, Adrian Sherman, Salik Nazki, Jason S. Long, Michael A. Skinner, Holly Shelton, Helen M. Sang, Wendy S. Barclay & Mike J. McGrew. Nature Communications volume 14, Article number: 6136 (2023) DOI: https://doi.org/10.1038/s41467-023-41476-3 Published: 10 October 2023

This paper is open access.

CRISPR-like system found in animals

I trust the eukaryotes will not be suing for intellectual property rights. (For anyone who’s interested in CRISPR [clustered regularly interspaced short palindromic repeats) and associated intellectual property (specifically, patent) issues, see my March 15, 2017 posting “CRISPR patent decision: Harvard’s and MIT’s Broad Institute victorious—for now.” It’s not up-to-date but as far as I know there haven’t been any major intellectual property developments since. If I’m wrong, please let me know in the Comments section of this posting.)

A june 28, 2023 news item on phys.org announces research suggesting there are naturally occurring CRISPR-like capabilities in some species,

A team of researchers led by Feng Zhang at the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT [Massachusetts Institute of Technology] has uncovered the first programmable RNA-guided system in eukaryotes—organisms that include fungi, plants, and animals.

In a study in Nature, the team describes how the system is based on a protein called Fanzor. They showed that Fanzor proteins use RNA as a guide to target DNA precisely, and that Fanzors can be reprogrammed to edit the genome of human cells. The compact Fanzor systems have the potential to be more easily delivered to cells and tissues as therapeutics than CRISPR/Cas systems, and further refinements to improve their targeting efficiency could make them a valuable new technology for human genome editing

A june 28, 2023 Broad Institute of MIT and Harvard news release by Leah Eisenstadt (also on EurekAlert), which originated the news item, provides more context for the research,

CRISPR/Cas was first discovered in prokaryotes (bacteria and other single-cell organisms that lack nuclei) and scientists including Zhang’s lab have long wondered whether similar systems exist in eukaryotes. The new study demonstrates that RNA-guided DNA-cutting mechanisms are present across all kingdoms of life.

“CRISPR-based systems are widely used and powerful because they can be easily reprogrammed to target different sites in the genome,” said Zhang, senior author on the study and a core institute member at the Broad, an investigator at MIT’s McGovern Institute, the James and Patricia Poitras Professor of Neuroscience at MIT, and a Howard Hughes Medical Institute investigator. “This new system is another way to make precise changes in human cells, complementing the genome editing tools we already have.”

Searching the domains of life

A major aim of the Zhang lab is to develop genetic medicines using systems that can modulate human cells by targeting specific genes and processes. “A number of years ago, we started to ask, ‘What is there beyond CRISPR, and are there other RNA-programmable systems out there in nature?’” said Zhang.

Two years ago, Zhang lab members discovered a class of RNA-programmable systems in prokaryotes called OMEGAs, which are often linked with transposable elements, or “jumping genes”, in bacterial genomes and likely gave rise to CRISPR/Cas systems. That work also highlighted similarities between prokaryotic OMEGA systems and Fanzor proteins in eukaryotes, suggesting that the Fanzor enzymes might also use an RNA-guided mechanism to target and cut DNA.

In the new study, the researchers continued their study of RNA-guided systems by isolating Fanzors from fungi, algae, and amoeba species, in addition to a clam known as the Northern Quahog. Co-first author Makoto Saito of the Zhang lab led the biochemical characterization of the Fanzor proteins, showing that they are DNA-cutting endonuclease enzymes that use nearby non-coding RNAs known as ωRNAs to target particular sites in the genome. It is the first time this mechanism has been found in eukaryotes, such as animals.

Unlike CRISPR proteins, Fanzor enzymes are encoded in the eukaryotic genome within transposable elements and the team’s phylogenetic analysis suggests that the Fanzor genes have migrated from bacteria to eukaryotes through so-called horizontal gene transfer.

“These OMEGA systems are more ancestral to CRISPR and they are among the most abundant proteins on the planet, so it makes sense that they have been able to hop back and forth between prokaryotes and eukaryotes,” said Saito.

To explore Fanzor’s potential as a genome editing tool, the researchers demonstrated that it can generate insertions and deletions at targeted genome sites within human cells. The researchers found the Fanzor system to initially be less efficient at snipping DNA than CRISPR/Cas systems, but by systematic engineering, they introduced a combination of mutations into the protein that increased its activity 10-fold. Additionally, unlike some CRISPR systems and the OMEGA protein TnpB, the team found that a fungal-derived Fanzor protein did not exhibit “collateral activity,” where an RNA-guided enzyme cleaves its DNA target as well as degrading nearby DNA or RNA. The results suggest that Fanzors could potentially be developed as efficient genome editors.

Co-first author Peiyu Xu led an effort to analyze the molecular structure of the Fanzor/ωRNA complex and illustrate how it latches onto DNA to cut it. Fanzor shares structural similarities with its prokaryotic counterpart CRISPR-Cas12 protein, but the interaction between the ωRNA and the catalytic domains of Fanzor is more extensive, suggesting that the ωRNA might play a role in the catalytic reactions. “We are excited about these structural insights for helping us further engineer and optimize Fanzor for improved efficiency and precision as a genome editor,” said Xu.

Like CRISPR-based systems, the Fanzor system can be easily reprogrammed to target specific genome sites, and Zhang said it could one day be developed into a powerful new genome editing technology for research and therapeutic applications. The abundance of RNA-guided endonucleases like Fanzors further expands the number of OMEGA systems known across kingdoms of life and suggests that there are more yet to be found.

“Nature is amazing. There’s so much diversity,” said Zhang. “There are probably more RNA-programmable systems out there, and we’re continuing to explore and will hopefully discover more.”

The paper’s other authors include Guilhem Faure, Samantha Maguire, Soumya Kannan, Han Altae-Tran, Sam Vo, AnAn Desimone, and Rhiannon Macrae.

About Broad Institute of MIT and Harvard
Broad Institute of MIT and Harvard was launched in 2004 to empower this generation of creative scientists to transform medicine. The Broad Institute seeks to describe the molecular components of life and their connections; discover the molecular basis of major human diseases; develop effective new approaches to diagnostics and therapeutics; and disseminate discoveries, tools, methods and data openly to the entire scientific community.

Founded by MIT, Harvard, Harvard-affiliated hospitals, and the visionary Los Angeles philanthropists Eli and Edythe L. Broad, the Broad Institute includes faculty, professional staff and students from throughout the MIT and Harvard biomedical research communities and beyond, with collaborations spanning over a hundred private and public institutions in more than 40 countries worldwide.

About McGovern Institute for Brain Research at MIT
The McGovern Institute is an inclusive and collaborative community of MIT scientists, engineers, and support staff who work together to unravel the mysteries of the brain. Our researchers are committed to meeting two of the greatest challenges of modern science: understanding how the brain works and discovering new ways to prevent or treat brain disorders. To address this scientific challenge, we study the brain at many levels and collaborate with academic, clinical, and industry partners around the world.

The McGovern Institute was established in 2000 by technology entrepreneur Lore Harp McGovern and the late Patrick J. McGovern, former chairman of International Data Group (IDG). Our director is Robert Desimone, the Doris and Don Berkey Professor of Neuroscience at MIT and former head of intramural research at the National Institute of Mental Health. The McGovern Institute has grown from six founding faculty members to more than 20 distinguished investigators including one Nobel laureate and six members of the National Academy of Sciences.

.

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

Fanzor is a eukaryotic programmable RNA-guided endonuclease by Makoto Saito, Peiyu Xu, Guilhem Faure, Samantha Maguire, Soumya Kannan, Han Altae-Tran, Sam Vo, AnAn Desimone, Rhiannon K. Macrae & Feng Zhang. Nature (2023) DOI: https://doi.org/10.1038/s41586-023-06356-2 Published: 28 June 2023

This paper is behind a paywall.

A CRISPR (clustered regularly interspaced short palindromic repeats) anniversary

June 2022 was the 10th anniversary of the publication of a study the paved the way for CRISPR-Cas9 gene editing and Sophie Fessl’s June 28, 2022 article for The Scientist offers a brief history (Note: Links have been removed),

Ten years ago, Emmanuelle Charpentier and Jennifer Doudna published the study that paved the way for a new kind of genome editing: the suite of technologies now known as CRISPR. Writing in [the journal] Science, they adapted an RNA-mediated bacterial immune defense into a targeted DNA-altering system. “Our study . . . highlights the potential to exploit the system for RNA-programmable genome editing,” they conclude in the abstract of their paper—a potential that, in the intervening years, transformed the life sciences. 

From gene drives to screens, and diagnostics to therapeutics, CRISPR nucleic acids and the Cas enzymes with which they’re frequently paired have revolutionized how scientists tinker with DNA and RNA. … altering the code of life with CRISPR has been marred by ethical concerns. Perhaps the most prominent example was when Chinese scientist He Jiankui created the first gene edited babies using CRISPR/Cas9 genome editing. Doudna condemned Jiankui’s work, for which he was jailed, as “risky and medically unnecessary” and a “shocking reminder of the scientific and ethical challenges raised by this powerful technology.” 

There’s also the fact that legal battles over who gets to claim ownership of the system’s many applications have persisted almost as long as the technology has been around. Both Doudna and Charpentier’s teams from the University of California, Berkeley, and the University of Vienna and a team led by the Broad Institute’s Feng Zhang claim to be the first to have adapted CRISPR-Cas9 for gene editing in complex cells (eukaryotes). Patent offices in different countries have reached varying decisions, but in the US, the latest rulings say that the Broad Institute of MIT [Massachusetts Institute of Technology] and Harvard retains intellectual property of using CRISPR-Cas9 in eukaryotes, while Emmanuelle Charpentier, the University of California, and the University of Vienna maintain their original patent over using CRISPR-Cas9 for editing in vitro and in prokaryotes. 

Still, despite the controversies, the technique continues to be explored academically and commercially for everything from gene therapy to crop improvement. Here’s a look at seven different ways scientists have utilized CRISPR.

Fessl goes on to give a brief overview of CRISPR and gene drives, genetic screens, diagnostics, including COVID-19 tests, gene therapy, therapeutics, crop and livestock improvement, and basic research.

For anyone interested in the ethical issues (with an in depth look at the Dr. He Jiankui story), I suggest reading either or both Eben Kirksey’s 2020 book, “The Mutant Project; Inside the Global Race to Genetically Modify Humans,”

An anthropologist visits the frontiers of genetics, medicine, and technology to ask: Whose values are guiding gene editing experiments? And what does this new era of scientific inquiry mean for the future of the human species?

“That rare kind of scholarship that is also a page-turner.”
—Britt Wray, author of Rise of the Necrofauna

At a conference in Hong Kong in November 2018, Dr. He Jiankui announced that he had created the first genetically modified babies—twin girls named Lulu and Nana—sending shockwaves around the world. A year later, a Chinese court sentenced Dr. He to three years in prison for “illegal medical practice.”

As scientists elsewhere start to catch up with China’s vast genetic research program, gene editing is fueling an innovation economy that threatens to widen racial and economic inequality. Fundamental questions about science, health, and social justice are at stake: Who gets access to gene editing technologies? As countries loosen regulations around the globe, from the U.S. to Indonesia, can we shape research agendas to promote an ethical and fair society?

Eben Kirksey takes us on a groundbreaking journey to meet the key scientists, lobbyists, and entrepreneurs who are bringing cutting-edge genetic engineering tools like CRISPR—created by Nobel Prize-winning biochemists Jennifer Doudna and Emmanuelle Charpentier—to your local clinic. He also ventures beyond the scientific echo chamber, talking to disabled scholars, doctors, hackers, chronically-ill patients, and activists who have alternative visions of a genetically modified future for humanity.

and/or Kevin Davies’s 2020 book, “Editing Humanity: The CRISPR Revolution and the New Era of Genome Editing,”

One of the world’s leading experts on genetics unravels one of the most important breakthroughs in modern science and medicine. 

If our genes are, to a great extent, our destiny, then what would happen if mankind could engineer and alter the very essence of our DNA coding? Millions might be spared the devastating effects of hereditary disease or the challenges of disability, whether it was the pain of sickle-cell anemia to the ravages of Huntington’s disease.

But this power to “play God” also raises major ethical questions and poses threats for potential misuse. For decades, these questions have lived exclusively in the realm of science fiction, but as Kevin Davies powerfully reveals in his new book, this is all about to change.

Engrossing and page-turning, Editing Humanity takes readers inside the fascinating world of a new gene editing technology called CRISPR, a high-powered genetic toolkit that enables scientists to not only engineer but to edit the DNA of any organism down to the individual building blocks of the genetic code.

Davies introduces readers to arguably the most profound scientific breakthrough of our time. He tracks the scientists on the front lines of its research to the patients whose powerful stories bring the narrative movingly to human scale.

Though the birth of the “CRISPR babies” in China made international news, there is much more to the story of CRISPR than headlines seemingly ripped from science fiction. In Editing Humanity, Davies sheds light on the implications that this new technology can have on our everyday lives and in the lives of generations to come.

Kevin Davies is the executive editor of The CRISPR Journal and the founding editor of Nature Genetics. He holds an MA in biochemistry from the University of Oxford and a PhD in molecular genetics from the University of London. He is the author of Cracking the Genome, The $1,000 Genome, and co-authored a new edition of DNA: The Story of the Genetic Revolution with Nobel Laureate James D. Watson and Andrew Berry. In 2017, Kevin was selected for a Guggenheim Fellowship in science writing.

I’ve read both books and while some of the same ground is covered, the perspectives diverge somewhat. Both authors offer a more nuanced discussion of the issues than was the case in the original reporting about Dr. He’s work.

Tissue nanotransfection

I’m wondering how I missed the research from last year (2021) which foregrounds this latest work. Ah well. It happens. Making up for lost time, here’s a July 18, 2022 news item on phys.org about tissue nanotransfection, Note: Links have been removed,

The Indiana Center for Regenerative Medicine and Engineering (ICRME) at Indiana University School of Medicine is home to tissue nanotransfection (TNT) regenerative medicine technology that achieves functional tissue reprogramming in the live body. Last year, ICRME researchers published on how to manufacture the TNT 2.0 silicon chip hardware in Nature Protocol. Now, their research demonstrates for the first time that TNT can serve as a non-viral, topical gene-editing delivery device.

TNT is a minimally invasive device that can reprogram tissue function in the live body by applying pulses of harmless, electric sparks to deliver specific genes of interest to the skin.

“TNT-based delivery can achieve cell-specific gene editing,” said corresponding author Chandan K. Sen, Ph.D., the J. Stanley Battersby Chair and distinguished professor of surgery, director of the ICRME at IU School of Medicine and executive director of the Indiana University Health Comprehensive Wound Care Center. “Your skin has thousands of genes and in chronic wounds many key genes are silenced by DNA methylation. TNT-based gene editing technology can remove that barrier.”

A July 18, 2022 Indiana University School of Medicine news release (also on EurekAlert), which originated the news item, updates the information with some of the latest research, Note: Links have been removed,

In this study, genome-wide methylation was observed in the chronic wound tissue of patients. This was reproduced in an experimental murine model. TNT-based, cell-specific gene editing rescued wound healing. Results were published recently [July 12, 2022] in the Journal of Clinical Investigation.

Previous TNT application studies reported on the rescue of injured legs, diabetic neuropathy, crushed nerve and the stroke-affected brain. This is the first time promoter methylation of genes is recognized as a critical barrier to wound healing. In this study, ICRME investigators found that P53 methylation and gene silencing as a critical barrier to cutaneous wound epithelial-to-mesenchymal transition (EMT), a mechanism that is necessary to close skin wounds. TNT based non-viral keratinocyte-specific demethylation of P53 gene rescued EMT and achieved wound closure.

Chronic wounds can result in serious and sometimes life-threatening complications from an abundance of dying and necrotic tissue, such as cellulitis, lower-extremity amputation and sepsis. Treating chronic wounds is estimated to cost the United States health care system $28 billion annually, which amplifies the need to test novel treatments to prevent amputation, save lives and lower health care costs.

“Inspired by observations in chronic wound patients, this work has achieved an important milestone highlighting the need to de-silence genes at the wound-site,” said first author Kanhaiya Singh, PhD, assistant professor of surgery and an investigator at the ICRME.

Here are two links and citations. First, the earlier work,

Fabrication and use of silicon hollow-needle arrays to achieve tissue nanotransfection in mouse tissue in vivo by Yi Xuan, Subhadip Ghatak, Andrew Clark, Zhigang Li, Savita Khanna, Dongmin Pak, Mangilal Agarwal, Sashwati Roy, Peter Duda & Chandan K. Sen. Nature Protocols volume 16, pages 5707–5738 (2021) DOI: https://doi.org/10.1038/s41596-021-00631-0 Published: 26 November 2021 Issue Date: December 2021

This paper is behind a paywall.

Now, the latest work

Genome-wide DNA hypermethylation opposes healing in chronic wound patients by impairing epithelial-to-mesenchymal transition by Kanhaiya Singh, Yashika Rustagi, Ahmed S. Abouhashem, Saba Tabasum, Priyanka Verma, Edward Hernandez, Durba Pal, Dolly K. Khona, Sujit K. Mohanty, Manishekhar Kumar, Rajneesh Srivastava, Poornachander R Guda, Sumit S. Verma, Sanskruti Mahajan, Jackson A. Killian, Logan A. Walker, Subhadip Ghatak, Shomita S. Mathew-Steiner, Kristen Wanczyk, Sheng Liu, Jun Wan, Pearlly Yan, Ralf Bundschuh, Savita Khanna, Gayle M. Gordillo, Michael P. Murphy, Sashwati Roy, and Chandan K. Sen. J Clin Invest. DOI: https://doi.org/10.1172/JCI157279 Published: July 12, 2022 Version 1 (In-Press Preview) Version 2: J Clin Invest. 2022;132(17):e157279. https://doi.org/10.1172/JCI157279. Volume 132, Issue 17 Published September 1, 2022

This paper is open access.

Use Gene Editing to Make Better Babies (a February 17, 2022 livestreamed debate from 05:00 PM − 06:30 PM EST)

I have high hopes for this debate on gene edited babies. Intelligence Squared US convenes good debates. (I watched their ‘de-extinction’ debate back in 2019, which coincidentally, featured George Church, one of the debaters in this event.) Not ‘good’ in that I necessarily agree or am interested in the topics but good as in thoughtful. Here’s more from the organization’s mission on their What is IQ2US? webpage,

A nonpartisan, nonprofit organization, Intelligence Squared U.S. addresses a fundamental problem in America: the extreme polarization of our nation and our politics.

Our mission is to restore critical thinking, facts, reason, and civility to American public discourse.

More about the upcoming debate can be found on the Use Gene Editing to Make Better Babies event page,

Use Gene Editing to Make Better Babies
Hosted By John Donvan

Thursday, February 17, 2022
05:00 PM − 06:30 PM EST

A genetic disease runs in your family. Your doctor tells you that, should you wish to have a child, that child is likely to also carry the disease. But a new gene-editing technology could change your fate. It could ensure that your baby is — and remains — healthy. Even more, it could potentially make sure your grandchildren are also free of the disease. What do you do? Now, imagine it’s not a rare genetic disorder, but general illness, or eye color, or cognitive ability, or athleticism. Do you opt into this new world of genetically edited humans? And what if it’s not just you. What your friends, neighbors, and colleagues are also embracing this genetic revolution? Right now, science doesn’t give you that choice. But huge advancements in CRISPR [clustered regularly interspaced short palindromic repeats] technology are making human gene editing a reality. In fact, in 2018, a Chinese scientist announced the first genetically modified babies; twin girls made to resist HIV, smallpox, and malaria. The promise of this technology is clear. But gene editing is not without its perils. Its critics say the technology is destined to exacerbate inequality, pressure all parents (and nations) into editing their children to stay competitive, and meddling with the most basic aspect of our humanity. In this context, we ask the question: Should we use gene editing to make better babies?

Main Points

The use of gene editing allows for couples to have children when they might otherwise have that option unavailable for them. It also allows for less to be left to chance during the pregnancy.

Gene editing will allow for babies to be born with reduced or eliminated chances of inheriting and passing on genes linked to diseases. We have a moral imperative to use technology that will improve the quality of life.

It is only a matter of time before gene editing becomes a widespread technology, potentially used by competitors and rivals on the international stage. If we have the technology, we should use it to our advantage to remain competitive.

The use of gene editing to create “better” outcomes in children will inherently create social stratification based on any gene editing, likely reflecting existing socioeconomic status. Additionally, the term ‘better’ is arbitrary and potentially short-sighted and dangerous.

Currently, there exist reasonable alternatives to gene editing for every condition for which gene editing can be used. 

The technology is still developing, and the long-term effects of any gene-editing could be potentially dangerous with consequences echoing throughout the gene environment. 

A February 8, 2022 Intelligence Squared U.S. news release about the upcoming debate (received via email) provides details about the debaters,

FOR THE MOTION – BIOS

* George Church, Geneticist & Founder, Personal Genome Project 
George Church is one of the nation’s leading geneticists and scholars. He is a professor of genetics at Harvard Medical School and MIT. In 1984, he developed the first direct genomic sequencing method, which resulted in the first genome sequence. He also helped initiate the Human Genome Project in 1984 and the Personal Genome Project in 2005. Church also serves as the director of the National Institutes of Health Center of Excellence in Genomic Science.  

* Amy Webb, Futurist & Author, “The Genesis Machine”  
Amy Webb is an award-winning author and futurist. She is the founder and CEO of the Future Today Institute and was named one of five women changing the world by Forbes. Her new book, “The Genesis Machine,” explores the future of synthetic biology, including human gene editing. Webb is a professor of strategic foresight at New York University’s Stern School of Business and has been elected a life member of the Council on Foreign Relations.  

AGAINST THE MOTION – BIOS

* Marcy Darnovsky, Policy Advocate & Executive Director, Center for Genetics and Society 
Marcy Darnovsky is a policy advocate and one of the most prominent voices on the politics of human biotechnology. As executive director of the Center for Genetics and Society, Darnovsky is focused on the social justice and public interest implications of gene editing. This work is informed by her background as an organizer and advocate in a range of environmental and progressive political movements.    

* Françoise Baylis, Philosopher & Author, “Altered Inheritance”  
Françoise Baylis is a philosopher whose innovative work in bioethics, at the intersection of policy and practice, has stretched the very boundaries of the field. She is the author of “Altered Inheritance: CRISPR and the Ethics of Human Genome Editing,” which explores the scientific, ethical, and political implications of human genome editing. Baylis is a research professor at Dalhousie University and a fellow of the Canadian Academy of Health Sciences. In 2017, she was awarded the Canadian Bioethics Society Lifetime Achievement Award. 

Getting back to the Use Gene Editing to Make Better Babies event page, there are a few options,

Request a Ticket

Have a question? Ask us

There’s also an option to Vote For or Against the Motion but you’ll have to go to the Use Gene Editing to Make Better Babies event page.

Two of the debaters have been mentioned on this blog before, George Church and Françoise Baylis. There are several references to Church including this mention with regard to Dr. He Jiankui and his CRISPR twins (July 28, 2020 posting). Françoise Baylis features in four 2019 postings with the most recent being this October 17, 2019 piece.

For anyone curious about the ‘de-extinction’ debate, it was described here in a January 18, 2019 posting prior to the event.

World CRISPR Day on October 20, 2021 from 8:00 a.m. – 6:00 p.m. PDT

H/t to rapper Baba Brinkman (born in Canada and based in New York City) for the tweet/retweet about his upcoming appearance at World CRISPR (clustered regularly interspaced palindromic repeats) Day on October 20, 2021 from 8:00 a.m. – 6:00 p.m. PDT,

Baba Brinkman @BabaBrinkman

True facts! I’ve been working with incredible #CRISPR innovator @Synthego and the @EventRapInc team, and tomorrow is #WorldCRISPRDay! Look for new DNA-themed videos and streamed performances all day from @HilaTheKilla, @CoreyJGray, @ZEPS, @MCAbdominal and me. Sign up to watch!

Synthego
@Synthego· 2h
Multiple musical notes BREAKING NEWS Multiple musical notes We’re delighted to announce that @BabaBrinkman will be performing live at #WorldCRISPRDay! Register today so you don’t miss out on this special and exclusive performance at the biggest event in #CRISPR! https://hubs.li/H0ZGfSG0

World CRISPR Day (it’s free) is being hosted by Synthego, from their About Us (company) webpage,

Synthego is a genome engineering company that enables the acceleration of life science research and development in the pursuit of improved human health.

The company leverages machine learning, automation, and gene editing to build platforms for science at scale. With its foundations in engineering disciplines, the company’s platform technologies vertically integrate proprietary hardware, software, bioinformatics, chemistries, and molecular biology to advance basic research, target validation, and clinical trials.

With its technologies cited in hundreds of peer-reviewed publications and utilized by thousands of commercial and academic researchers and therapeutic drug developers, Synthego is at the forefront of innovation enabling the next generation of medicines by delivering genome editing at an unprecedented scale.

Here’s the company’s (undated) announcement about the upcoming World CRISPR Day,

Synthego is proud to host the 2nd annual World CRISPR Day virtual event on October 20, 2021, where we can share, listen, and learn about the latest advancements in CRISPR. The day will include presentations from the world’s leading Genome Engineers, a panel discussion featuring the women of CRISPR, and much more! Don’t miss your chance to learn from the experts how CRISPR is editing the future of medicine.

Despite the COVID-related challenges that the global research community continues to face, scientists have persevered in their relentless pursuit of advancing human health. The field of CRISPR has been no exception. With development of new CRISPR innovations, drug discovery and diagnostic methods, and numerous successful reports of CRISPR-based cell and gene therapy clinical trials, the promise of CRISPR in the clinic is becoming a reality.

Join us at World CRISPR Day to hear academic and industry experts talk about their transformative research, visit our partner’s booths, take advantage of the different networking sessions with your peers, and much more!

Register now for free!

You can find World CRISPR Day 2021 here and you can find Baba Brinkman’s website here.

Having looked at the pop up pages describing the panel discussions and participants and having looked at their World CRISPR Day 2021 and 2020 videos, I strongly suspect that this day focuses on CRISPR as the solution to any number of problems in the life sciences, an area, where coincidentally, Synthego and its partners have significant expertise. With that proviso in mind, I’m sure this will be a very interesting and worthwhile day.

Precision targeting of the liver for gene editing

Apparently the magic is in the lipid nanoparticles. A March 1, 2021 news item on Nanowerk announced research into lipid nanoparticles as a means to deliver CRISPR (clustered regularly interspaced short palindromic repeats) to specific organs (Note: A link has been removed),

The genome editing technology CRISPR has emerged as a powerful new tool that can change the way we treat disease. The challenge when altering the genetics of our cells, however, is how to do it safely, effectively, and specifically targeted to the gene, tissue and organ that needs treatment.

Scientists at Tufts University and the Broad Institute of Harvard [University] and MIT [Massachusetts Institute of Technology] have developed unique nanoparticles comprised of lipids — fat molecules — that can package and deliver gene editing machinery specifically to the liver.

In a study published in the Proceedings of the National Academy of Sciences [PNAS] (“Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3”), they have shown that they can use the lipid nanoparticles (LNPs) to efficiently deliver the CRISPR machinery into the liver of mice, resulting in specific genome editing and the reduction of blood cholesterol levels by as much as 57% — a reduction that can last for at least several months with just one shot.

A March 2, 2021 Tufts University news release (also on EurekAlert but published March 1, 2021), which originated the news item, provides greater insight into and technical detail about the research,

The problem of high cholesterol plagues more than 29 million Americans, according to the Centers for Disease Control and Prevention. The condition is complex and can originate from multiple genes as well as nutritional and lifestyle choices, so it is not easy to treat. The Tufts and Broad researchers, however, have modified one gene that could provide a protective effect against elevated cholesterol if it can be shut down by gene editing.

The gene that the researchers focused on codes for the angiopoietin-like 3 enzyme (Angptl3). That enzyme tamps down the activity of other enzymes – lipases – that help break down cholesterol. If researchers can knock out the Angptl3 gene, they can let the lipases do their work and reduce levels of cholesterol in the blood. It turns out that some lucky people have a natural mutation in their Angptl3 gene, leading to consistently low levels of triglycerides and low-density lipoprotein (LDL) cholesterol, commonly called “bad” cholesterol, in their bloodstream without any known clinical downsides.

“If we can replicate that condition by knocking out the angptl3 gene in others, we have a good chance of having a safe and long term solution to high cholesterol,” said Qiaobing Xu, associate professor of biomedical engineering at Tufts’ School of Engineering and corresponding author of the study. “We just have to make sure we deliver the gene editing package specifically to the liver so as not to create unwanted side effects.”

Xu’s team was able to do precisely that in mouse models. After a single injection of lipid nanoparticles packed with mRNA coding for CRISPR-Cas9 and a single-guide RNA targeting Angptl3, they observed a profound reduction in LDL cholesterol by as much as 57% and triglyceride levels by about 29 %, both of which remained at those lowered levels for at least 100 days. The researchers speculate that the effect may last much longer than that, perhaps limited only by the slow turnover of cells in the liver, which can occur over a period of about a year. The reduction of cholesterol and triglycerides is dose dependent, so their levels could be adjusted by injecting fewer or more LNPs in the single shot, the researchers said.

By comparison, an existing, FDA [US Food and Drug Administration]-approved version of CRISPR mRNA-loaded LNPs could only reduce LDL cholesterol by at most 15.7% and triglycerides by 16.3% when it was tested in mice, according to the researchers.

The trick to making a better LNP was in customizing the components – the molecules that come together to form bubbles around the mRNA. The LNPs are made up of long chain lipids that have a charged or polar head that is attracted to water, a carbon chain tail that points toward the middle of the bubble containing the payload, and a chemical linker between them. Also present are polyethylene glycol, and yes, even some cholesterol – which has a normal role in lipid membranes to make them less leaky – to hold their contents better.

The researchers found that the nature and relative ratio of these components appeared to have profound effects on the delivery of mRNA into the liver, so they tested LNPs with many combinations of heads, tails, linkers and ratios among all components for their ability to target liver cells. Because the in vitro potency of an LNP formulation rarely reflects its in vivo performance, they directly evaluated the delivery specificity and efficacy in mice that have a reporter gene in their cells that lights up red when genome editing occurs. Ultimately, they found a CRISPR mRNA-loaded LNP that lit up just the liver in mice, showing that it could specifically and efficiently deliver gene-editing tools into the liver to do their work.

The LNPs were built upon earlier work at Tufts, where Xu and his team developed LNPs with as much as 90% efficiency in delivering mRNA into cells. A unique feature of those nanoparticles was the presence of disulfide bonds between the long lipid chains. Outside the cells, the LNPs form a stable spherical structure that locks in their contents. When they are inside a cell, the environment within breaks the disulfide bonds to disassemble the nanoparticles. The contents are then quickly and efficiently released into the cell. By preventing loss outside the cell, the LNPs can have a much higher yield in delivering their contents.

“CRISPR is one of the most powerful therapeutic tools for the treatment of diseases with a genetic etiology. We have recently seen the first human clinical trail for CRISPR therapy enabled by LNP delivery to be administered systemically to edit genes inside the human body. Our LNP platform developed here holds great potential for clinical translation,” said Min Qiu, post-doctoral researcher in Xu’s lab at Tufts.  “We envision that with this LNP platform in hand, we could now make CRISPR a practical and safe approach to treat a broad spectrum of liver diseases or disorders,” said Zachary Glass, graduate student in the Xu lab. Qiu and Glass are co-first authors of the study.

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

Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3 by Min Qiu, Zachary Glass, Jinjin Chen, Mary Haas, Xin Jin, Xuewei Zhao, Xuehui Rui, Zhongfeng Ye, Yamin Li, Feng Zhang, and Qiaobing Xu. PNAS March 9, 2021 118 (10) e2020401118 DOI: https://doi.org/10.1073/pnas.2020401118

This paper appears to be behind a paywall.

Toronto’s ArtSci Salon and The Mutant Project March 15, 2021

The Mutant Project is both a book (The Mutant Project: Inside the Global Race to Genetically Modify Humans) and an event about gene editing with special reference to the CRISPR (clustered regularly interspaced short palindromic repeats) twins, Lulu and Nana. The event is being held by Toronto’s ArtSci Salon. Here’s more from their March 3, 2021 announcement (received via email),

The Mutant Project

A talk and discussion with Eben Kirksey

Discussants:

Dr. Elizabeth Koester, Postdoctoral fellow, Department of History, UofT [University of Toronto]

Vincent Auffrey, PhD student, IHPST [Institute for the History and Philosophy of Science and Technology], UofT

Fan Zhang, PhD student, IHPST, UofT

This event will be streamed on Zoom and on Youtube

Here is the link to register to Zoom on the 15th:

https://utoronto.zoom.us/meeting/registe/tZErcemoqzwrG9foNF5Ud86uJXdNeIzQSfDw

Event on FB: https://www.facebook.com/events/4033393163381012/

YouTube: https://www.youtube.com/watch?v=pEFfj3Ovsfk&feature=youtu.be

At a conference in Hong Kong in November 2018, Dr. He Jiankui announced that he had created the first genetically modified babies—twin girls named Lulu and Nana—sending shockwaves around the world. A year later, a Chinese court sentenced Dr. He to three years in prison for “illegal medical practice.”

As scientists elsewhere start to catch up with China’s vast genetic research program, gene editing is fueling an innovation economy that threatens to widen racial and economic inequality. Fundamental questions about science, health, and social justice are at stake: Who gets access to gene editing technologies? As countries loosen regulations around the globe, from the U.S. to Indonesia, can we shape research agendas to promote an ethical and fair society?

Join us to welcome Dr. Kirksey, who will discuss key topics from his book “The Mutant Project”.

The talk will be followed by a Q&A

EBEN KIRKSEY is an American anthropologist who finished his latest book as a Member of the Institute for Advanced Study in Princeton, New Jersey. He has been published in Wired, The Atlantic, The Guardian and The Sunday Times. He is sought out as an expert on science in society by the Associated Press, The Wall Street Journal, The New York Times, Democracy Now, Time and the BBC, among other media outlets. He speaks widely at the world’s leading academic institutions including Oxford, Yale, Columbia, UCLA, and the International Summit of Human Genome Editing, plus music festivals, art exhibits, and community events. Professor Kirksey holds a long-term position at Deakin University in Melbourne, Australia. For more information, please visit https://eben-kirksey.space/.

Elizabeth Koester currently holds a SSHRC [Social Science and Humanities Research Council of Canada] Postdoctoral Fellowship in the Department of History at the University of Toronto. After practising law for many years, she undertook graduate studies in the history of medicine at the Institute for the History and Philosophy of
Science and Technology at the University of Toronto and was awarded a PhD in 2018. A book based on her dissertation, In the Public Good: Eugenics and Law in Ontario, will be published by McGill-Queen’s University Press and is anticipated for Fall 2021.

Vincent Auffrey is pursuing his PhD at the Institute for the History of Philosophy of Science and Technology (IHPST) at the University of Toronto. His focus is set primarily on the social history of medicine and the history of eugenics in Canada. Secondary interests include the histories of scientific racism and of anatomy, and the interplay between knowledge and power.

Fan Zhang is a PhD student at the History of Philosophy of Science and Technology (IHPST) at the University of Toronto

Kirksey’s eponymous website,

CRISPR/Cas9 used successfully to edit SIV (simian immunodeficiency virus, which is similar to HIV) out of monkey genome

Before reading further please note, the research discussed in this posting is based on animal testing, which many people find highly disturbing.

CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9), or more familiarly CRISPR/Cas9, has been been used to edit simian immunodeficiency virus from infected monkeys’ cells according to a December 2, 2020 article by Matthew Rozsa for Salon.com (Note: Links have been removed),

With multiple coronavirus vaccines being produced as we speak, the COVID-19 pandemic appears to have an end in sight, though the HIV pandemic continues after more than 40 years. That might seem like a head-scratcher: why is HIV, a virus we’ve known about for decades, so much harder to cure than a virus discovered just last year? Part of the reason is that HIV, as a retrovirus, is a more complex virus to vaccinate against than SARS-CoV-2 — hence why a vaccine or other cure has eluded scientists for decades. 

Now, a surprising new study on a related retrovirus shows incredible promise for the potential to develop a cure for HIV, or human immunodeficiency virus. In an article published in the scientific journal Nature Communications, scientists revealed that they had used CRISPR – a genetic technology that can alter DNA and whose developers won the 2020 Nobel Prize in Chemistry [specifically, Jennifer Doudna and Emanuelle Charpentier received the Nobel for developing CRISPR-cas9 or CRISPR/Cas9 not CRISPR alone) — to successfully edit SIV (simian immunodeficiency virus), a virus similar to HIV, out of the genomes of non-human primates.  Specifically, the scientists were able to edit out the SIV genome from rhesus macaque monkeys’ infected cells.

For anyone who’s interested in how CRISPR was developed and the many contributions which have led to the current state-of-the-art for CRISPR gene editing, see the History subsection of Wikipedia’s CRISPR entry.

Getting back to Rozsa’s December 2, 2020 article,

“This study used the CRISPR CaS9 system, which has been described as molecular scissors,” Andrew G. MacLean, PhD, wrote to Salon. MacLean is an associate professor at the Tulane National Primate Research Center and the Department of Microbiology and Immunology at Tulane University School of Medicine and was a senior co-investigator of the study. “It uses a highly specific targeting system to cut out a specific portion of DNA that is necessary for HIV to be able to produce more virus.”

He added, “Our collaborators at in the Khalili Lab at Temple University have developed a method of ‘packaging’ this within a single so-called vector. A vector is a non-disease causing virus that is used as a carrier for the CRISPR CaS9 scissors to get it into the tissues of interest.”

The experiments with SIV are considered to be a gateway to understanding HIV, as HIV is believed to have evolved from SIV, and is genetically similar.

“The rhesus macaque model of HIV/AIDS is the most valuable model to test efficacy of new interventions or approaches for preventing or treating HIV infection, prior to human clinical trials,” Binhua Ling, PhD, associate professor at the Southwest National Primate Research Center, Texas Biomedical Research Institute, wrote to Salon. “This first proof-of-principal [emphasis mine] study on the rhesus macaque model indicates that this virus-vehicle-delivered-CRISPR system can reach many tissue sites of the body, and is able to effectively delete virus DNA in infected cells. This paves the way for applying the same technology to the human body, which could lead to a cure for HIV infection.”

Tricia H. Burdo, PhD, another senior co-investigator on the new study who works at the Lewis Katz School of Medicine at Temple University, explained to Salon by email that “HIV is in a class of viruses (retroviruses) that inserts itself into the DNA of the host, so you can really think of this now as a genetic disease” — in other words, the kind of thing that would be ripe for CRISPR’s scissors-like ability to remove errant or unwanted genetic material. Burdo notes that the CRISPR technology discussed in the article “cuts out this foreign viral gene.”

The study was conducted on eight Rhesus macaque monkeys. That is a very small number to start with and not all of the monkeys received the CRISPR/Cas9 treatment. From the ‘Animals used in the study and ethical statement‘ subsection of the study, “Animals were sacrificed for tissue collection 3 weeks after … .” Leaving aside how anyone may feel about ‘sacrificing …’, three weeks is not a long time for observation.

Should you be interested, there is a November 30, 2020 Tulane University news release announcing the research.

If you want to read the whole study, here’s a link and a citation,

CRISPR based editing of SIV proviral DNA in ART treated non-human primates by Pietro Mancuso, Chen Chen, Rafal Kaminski, Jennifer Gordon, Shuren Liao, Jake A. Robinson, Mandy D. Smith, Hong Liu, Ilker K. Sariyer, Rahsan Sariyer, Tiffany A. Peterson, Martina Donadoni, Jaclyn B. Williams, Summer Siddiqui, Bruce A. Bunnell, Binhua Ling, Andrew G. MacLean, Tricia H. Burdo & Kamel Khalili. Nature Communications volume 11, Article number: 6065 (2020) DOI: https://doi.org/10.1038/s41467-020-19821-7 Published: 27 November 2020

This paper is open access.

As Rozsa notes in his December 2, 2020 article, the Joint United Nations Programme on HIV/AIDS estimates that 32.7 million [24.8 million–42.2 million] people have died from AIDS-related illnesses since the start (1981?) of the epidemic to the end of 2019.

“transforming a plant is still an art” even with CRISPR

“Plus ça change, plus c’est la même chose (the more things change, the more things stay the same), is an old French expression that came to mind when I stumbled across two stories about genetic manipulation of food-producing plants.

The first story involves CRISPR (clustered regularly interspersed short palindromic repeats) gene editing and the second involves more ancient ways to manipulate plant genetics.

Getting ‘CRISPR’d’ plant cells to grow into plants

Plants often don’t grow from cells after researchers alter their genomes. Using a new technology, a team coaxed wheat (above) and other crops to more readily produce genome-edited healthy adult plants. Credit: Juan Debernardi

An October 13, 2020 news item on phys.org announces research about getting better results after a plant’s genome has been altered,

Researchers know how to make precise genetic changes within the genomes of crops, but the transformed cells often refuse to grow into plants. One team has devised a new solution.

Scientists who want to improve crops face a dilemma: it can be difficult to grow plants from cells after you’ve tweaked their genomes.

A new tool helps ease this process by coaxing the transformed cells, including those modified with the gene-editing system CRISPR-Cas9, to regenerate new plants. Howard Hughes Medical Institute Research Specialist Juan M. Debernardi and Investigator Jorge Dubcovsky, together with David Tricoli at the University of California, Davis [UC Davis] Plant Transformation Facility, Javier Palatnik from Argentina, and colleagues at the John Innes Center [UK], collaborated on the work. The team reports the technology, developed in wheat and tested in other crops, October 12, 2020, in the journal Nature Biotechnology.

An October 12, 2020 Howard Hughes Medical Institute (HHMI) news release, which originated the news item, provides more detail,

“The problem is that transforming a plant is still an art [emphasis mine],” Dubcovsky says. The success rate is often low – depending on the crop being modified, 100 attempts may yield only a handful of green shoots that can turn into full-grown plants. The rest fail to produce new plants and die. Now, however, “we have reduced this barrier,” says Dubcovsky, a plant geneticist at UC Davis. Using two genes that already control development in many plants, his team dramatically increased the formation of shoots in modified wheat, rice, citrus, and other crops.

Although UC Davis has a pending patent for commercial applications, Dubcovsky says the technique is available to any researcher who wants to use it for research, at no charge. A number of plant breeding companies have also expressed interested in licensing it. “Now people are trying it in multiple crops,” he says.

Humans have worked to improve plants since the dawn of agriculture, selecting wild grasses to produce cultivated maize and wheat, for example. Nowadays, though, CRISPR has given researchers the ability to make changes to the genome with surgical precision. They have used it to create wheat plants with larger grains, generate resistance to fungal infection, design novel tomato plant architectures, and engineer other traits in new plant varieties.

But the process isn’t easy. Scientists start out with plant cells or pieces of tissue, into which they introduce the CRISPR machinery and a small guide to the specific genes they’d like to edit. They must then entice the modified cells into forming a young plant. Most don’t sprout – a problem scientists are still working to understand.

They have tried to find work-arounds, including boosting the expression of certain genes that control early stages of plant development. While this approach has had some success, it can lead to twisted, stunted, sterile plants if not managed properly.Dubcovsky and his colleagues looked at two other growth-promoting genes, GRF and GIF, that work together in young tissues or organs of plants ranging from moss to fruit trees. The team put these genes side-by-side, like a couple holding hands, before adding them to plant cells. “If you go to a dance, you need to find your partner,” Dubcovsky says. “Here, you are tied with a rope to your partner.”

Dubcovsky’s team found that genetically altered wheat, rice, hybrid orange, and other crops produced many more shoots if those experiments included the linked GRF and GIF genes. In experiments with one variety of wheat, the appearance of shoots increased nearly eight-fold. The number of shoots in rice and the hybrid orange, meanwhile, more than doubled and quadrupled, respectively. What’s more, these shoots grew into healthy plants capable of reproducing on their own, with none of the defects that can result when scientists boost other development-controlling genes. That’s because one of the genes is naturally degraded in adult tissues, Dubcovsky says.

Caroline Roper, a plant pathologist at University of California, Riverside who was not involved in the work, plans to use the new technology to study citrus greening, a bacterial disease that kills trees and renders oranges hard and bitter.

To understand how citrus trees can protect themselves, she needs to see how removing certain genes alters their susceptibility to the bacterium — information that could lead to ways to fight the disease. With conventional techniques, it could take at least two years to generate the gene-edited plants she needs. She hopes Dubcovsky’s tool will shorten that timeline.  

“Time is of the essence. The growers, they wanted an answer yesterday, because they’re at the brink of having to abandon cultivating citrus,” she says.

For anyone who noticed the reference to citrus greening in the last paragraphs of this news release, I have more information aboutthe disease and efforts to it in an August 6, 2020 posting.

As for the latest in gene editing and regeneration, here’s a link to and a citation for the paper,

A GRF–GIF chimeric protein improves the regeneration efficiency of transgenic plants by Juan M. Debernardi, David M. Tricoli, Maria F. Ercoli, Sadiye Hayta, Pamela Ronald, Javier F. Palatnik & Jorge Dubcovsky. Nature Biotechnology volume 38, pages 1274–1279(2020) DOI: https://doi.org/10.1038/s41587-020-0703-0 First Published Online: 12 October 2020 Journal Issue Date: November 2020

This paper is behind a paywall.

Ancient farming techniques for engineering crops

I stumbled on this story by Gabriela Serrato Marks for Massive Science almost three years late (it’s a Dec. 5, 2017 article),

There are more than 50 strains of maize, called landraces, grown in Mexico. A landrace is similar to a dog breed: Corgis and Huskies are both dogs, but they were bred to have different traits. Maize domestication worked the same way.

Some landraces of maize can grow in really dry conditions; others grow best in wetter soils. Early maize farmers selectively bred maize landraces that were well-adapted to the conditions on their land, a practice that still continues today in rural areas of Mexico.

If you think this sounds like an early version of genetic engineering, you’d be correct. But nowadays, modern agriculture is moving away from locally adapted strains and traditional farming techniques and toward active gene manipulation. The goal of both traditional landrace development and modern genetic modification has been to create productive, valuable crops, so these two techniques are not necessarily at odds.

But as more farmers converge on similar strains of (potentially genetically modified) seeds instead of developing locally adapted landraces, there are two potential risks: one is losing the cultural legacy of traditional agricultural techniques that have been passed on in families for centuries or even millennia, and another is decreasing crop resilience even as climate variability is increasing.

Mexico is the main importer of US-grown corn, but that imported corn is primarily used to feed livestock. The corn that people eat or use to make tortillas is grown almost entirely in Mexico, which is where landraces come in.

It is a common practice to grow multiple landraces with different traits as an insurance policy against poor growth conditions. The wide range of landraces contains a huge amount of genetic diversity, making it less likely that one adverse event, such as a drought or pest infestation, will wipe out an entire crop. If farmers only grow one type of corn, the whole crop is vulnerable to the same event.

Landraces are also different from most commercially available hybrid strains of corn because they are open pollinating, which means that farmers can save seeds and replant them the next year, saving money and preserving the strain. If a landrace is not grown anymore, its contribution to maize’s genetic diversity is permanently lost.

This diversity was cultivated over generations from maize’s wild cousin, teosinte, by 60 groups of indigenous people in Mexico. Teosinte looks like a skinny, hairier version of maize. It still grows wild in some parts of Central America, but its close relatives have been found, domesticated, at archaeological sites in the region over 9,000 years old. These early maize cobs could easily fit in the palm of your hand – not big enough to be a staple crop that early farmers could depend upon for sustenance. Genetically, they were more similar to wild teosinte than to modern maize.

[] archaeologists also found that the cobs in Honduras, which is outside the natural range of teosinte, were larger than cobs of the same age from the original domestication region in southern Mexico. The scientists think that people in Honduras were able to develop more productive maize landraces because their crops were isolated from wild teosinte.

The size and shape of the ancient cobs from Honduras show that early farmers engineered the maize crop [emphasis mine] to make it more productive. They developed unique landraces that were well adapted to local conditions and successfully cultivated enough maize to support their communities. In many ways, they were early geneticists. [emphasis mine] …

We have a lot to learn from the indigenous farmers who were growing maize 4,000 years ago. Their history provides examples of both environmentally sound genetic modification and effective adaptation to climate variability. [emphases mine] …

Plus ça change …, eh?