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takyon writes:

The Scientist reports that University of Tokyo researchers have created a CRISPR-Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats using CRISPR associated protein 9) enzyme for gene editing that only works when activated by blue light. Photoactivatable CRISPR-Cas9 offers greater precision and control of gene editing:

Recently, University of Tokyo chemist Moritoshi Sato and his colleagues developed pairs of photoswitching proteins called Magnets, which use electrostatic interactions to come together when activated by light. The team has also used photoactivatable technology to develop a light-activated CRISPR-based transcription system to target specific genes for expression. Now, Sato's group has taken this one step further, using its Magnet proteins to create a photoactivatable Cas9 nuclease (paCas9) for light-controlled genome editing.

"The existing Cas9 does not allow to modify genome of a small subset of cells in tissue, such as neurons in the brain," Sato told The Scientist in an e-mail. "Additionally, the existing Cas9 often suffers from off-target effects due to its uncontrollable nuclease activity.... We have been interested in the development of a powerful tool that enables spatial and temporal control of genome editing."

The researchers created paCas9 by first splitting the Cas9 protein into two inactive fragments. They then coupled each fragment with one Magnet protein of a pair. When irradiated with blue light, the Magnets come together, bringing with them the split Cas9 fragments, which then merge to reconstitute the nuclease's RNA-guided activity. Importantly, the process is reversible: when the light is turned off, the paCas9 nuclease splits again, and nuclease activity is halted. "Such an on/off-switching property of paCas9 is the most important breakthrough previously unattainable," Sato said.

takyon writes:

We have previously covered CRISPR, its rising popularity, its breakthroughs, and creations.

Now, scientists at UC San Francisco and UC Berkeley have used CRISPR/Cas9 to modify human T cells in order to control immune functions:

Using their novel approach, the scientists were able to disable a protein on the T-cell surface called CXCR4, which can be exploited by HIV when the virus infects T cells and causes AIDS. The group also successfully shut down PD-1, a protein that has attracted intense interest in the burgeoning field of cancer immunotherapy, as scientists have shown that using drugs to block PD-1 coaxes T cells to attack tumors.

[In] practice, editing T cell genomes with CRISPR/Cas9 has proved surprisingly difficult, said Alexander Marson, PhD, a UCSF Sandler Fellow, and senior and co-corresponding author of the new study. "Genome editing in human T cells has been a notable challenge for the field," Marson said. "So we spent the past year and a half trying to optimize editing in functional T cells. There are a lot of potential therapeutic applications, and we want to make sure we're driving this as hard as we can."

[...] In lab dishes, the group assembled Cas9 ribonucleoproteins, or RNPs, which combine the Cas9 protein with single-guide RNA. They then used a method known as electroporation, in which cells are briefly exposed to an electrical field that makes their membranes more permeable, to quickly deliver these RNPs to the interior of the cells. With these innovations, the researchers successfully edited CXCR4 and PD-1, even knocking in new sequences to replace specific genetic "letters" in these proteins. The group was then able to sort the cells using markers expressed on the cell surface, to help pull out successfully edited cells for research, and eventually for therapeutic use.

[...] Marson stressed that, while recent reports of CRISPR/Cas9 editing of human embryos have stirred up controversy, T cells are created anew in each individual, so modifications would not be passed on to future generations. He hopes that Cas9-based therapies for T cell-related disorders, which include autoimmune diseases as well as immunodeficiencies such as "bubble boy disease," will enter the clinic in the future. "There's actually well-trodden ground putting modified T cells into patients. There are companies out there already doing it and figuring out the safety profile, so there's increasing clinical infrastructure that we could potentially piggyback on as we work out more details of genome editing," Marson said. "I think CRISPR-edited T cells will eventually go into patients, and it would be wrong not to think about the steps we need to take to get there safely and effectively."

The full paper [PDF] is available.

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takyon writes:

Following a September 3-4 meeting in Manchester, England, the Hinxton Group, "a global network of stem cell researchers, bioethicists, and experts on policy and scientific publishing" has published a statement backing the genetic modification of human embryos, with caveats:

It is "essential" that the genetic modification of human embryos is allowed, says a group of scientists, ethicists and policy experts. A Hinxton Group report says editing the genetic code of early stage embryos is of "tremendous value" to research. It adds although GM babies should not be allowed to be born at the moment, it may be "morally acceptable" under some circumstances in the future. The US refuses to fund research involving the gene editing of embryos. The global Hinxton Group met in response to the phenomenal advances taking place in the field of genetics.

From the statement:

Genome editing has tremendous value as a tool to address fundamental questions of human and non-human animal biology and their similarities and differences. There are at least four categories of basic research involving genome editing technology that can be distinguished: 1) research to understand and improve the technique of genome editing itself; 2) genome editing used as a tool to address fundamental questions of human and non-human animal biology; 3) research to generate preliminary data for the development of human somatic applications; and 4) research to inform the plausibility of developing safe human reproductive applications. These distinctions are important to make clear that, even if one opposes human genome editing for clinical reproductive purposes, there is important research to be done that does not serve that end. That said, we appreciate that there are even categories of basic research involving this technology that some may find morally troubling. Nevertheless, it is our conviction that concerns about human genome editing for clinical reproductive purposes should not halt or hamper application to scientifically defensible basic research.

BBC has this beginner's guide to the designer baby debate.

Related:

The Rapid Rise of CRISPR
NIH Won't Fund Human Germline Modification
Chinese Scientists Have Genetically Modified Human Embryos
UK Approves Three-Person IVF Babies

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takyon writes:

Dr. Kathy Niakan from the Francis Crick Institute is seeking approval from the UK's Human Fertilisation and Embryology Authority in order to genetically modify human embryos:

A scientist has been making her case to be the first in the UK to be allowed to genetically modify human embryos. Dr Kathy Niakan said the experiments would provide a deeper understanding of the earliest moments of human life and could reduce miscarriages. The regulator, the Human Fertilisation and Embryology Authority (HFEA), will consider her application on Thursday. If Dr Niakan is given approval then the first such embryos could be created by the summer.

[...] Dr Niakan, from the Francis Crick Institute, said: "We would really like to understand the genes needed for a human embryo to develop successfully into a healthy baby. The reason why it is so important is because miscarriages and infertility are extremely common, but they're not very well understood."

Of 100 fertilised eggs, fewer than 50 reach the blastocyst stage, 25 implant into the womb and only 13 develop beyond three months. She says that understanding what is supposed to happen and what can go wrong could improve IVF. "We believe that this research could really lead to improvements in infertility treatment and ultimately provide us with a deeper understanding of the earliest stages of human life."

However, she says the only way to do this is to edit human embryos. Many of the genes which become active in the week after fertilisation are unique to humans, so they cannot be studied in animal experiments. "The only way we can understand human biology at this early stage is by further studying human embryos directly," Dr Niakan said. Her intention is to use one of the most exciting recent scientific breakthroughs - Crispr gene editing - to turn off genes at the single-cell stage and see what happens. [...] She aims to start with the gene Oct4 which appears to have a crucial role.

Related: UK Approves Three-Person IVF Babies
The Rapid Rise of CRISPR
Group of Scientists and Bioethicists Back Genetic Modification of Human Embryos

Original Submission

"fork(2)" writes:

Soylent News has carried multiple previous articles about CRISPR, the "search and replace" tool for editing DNA (here, here, and here).

Now scientists at three sites that are members of the Parker Institute—UPenn, the University of San Francisco in California, and the University of Texas MD Anderson Cancer Center in Houston, have proposed a UPenn-led project to genetically modify T-cells to treat leukemia and other cancers. From an article by Jocelyn Kaiser in Science Magazine:

[...] The proposed clinical trial, in which researchers would use CRISPR to engineer immune cells to fight cancer, won approval from the Recombinant DNA Advisory Committee (RAC) at the U.S. National Institutes of Health, a panel that has traditionally vetted the safety and ethics of gene therapy trials funded by the U.S. government and others.

"It's an important new approach. We're going to learn a lot from this. And hopefully it form the basis of new types of therapy," says clinical oncologist Michael Atkins of Georgetown University in Washington, D.C., one of three RAC members who reviewed the protocol.

The 2-year trial will treat 18 people with myeloma, sarcoma, or melanoma, who have stopped responding to existing treatments, at three sites that are members of the Parker Institute—UPenn, the University of San Francisco in California, and the University of Texas MD Anderson Cancer Center in Houston. [Carl] June [of UPenn] pointed out to RAC that his team already has experience with gene editing. They have used a different technique, called zinc finger nucleases, to disrupt a gene on T cells that HIV uses to enter the cells. In a small trial, this strategy appeared to be safe and has shown promise for helping HIV patients. Those data suggest that CRISPR gene editing should be safe in humans, June said.

Although RAC endorsement is a big step, the researchers must now seek approval from their own institutions' ethics boards and the U.S. Food and Drug Administration. Others are likely nipping at their heels. Many thought the Cambridge, Massachusetts–based biotech company Editas Medicine would conduct the first CRISPR clinical trial—it has announced plans to use CRISPR to treat an inherited eye disease in 2017—but RAC has not yet reviewed a proposal from the company.

Original Submission

takyon writes:

Mammoth Biosciences adds the final piece of the CRISPR diagnostics puzzle to its toolkit

With the announcement today that Mammoth Biosciences has received the exclusive license from the University of California, Berkeley to the new CRISPR protein Cas14, the company now has the last piece of its diagnostics toolkit in place.

Cas14 is a newly discovered protein from the lab of Jennifer Doudna, a pioneer in gene-editing research and a member of the first research team to identify and unlock the power of CRISPR technology. Doudna and Mammoth Biosciences co-founder Lucas Harrington were part of the team of researchers to identify the new Cas14 protein, which can identify single-stranded DNA. The journal Science published their findings [DOI: 10.1126/science.aav4294] [DX] in October 2018.

"With the addition of this protein that is DNA binding and target single strands, it really means we can target any nucleic acid," says Mammoth chief executive Trevor Martin. "It's an extension of the toolbox." The licensing deal moves Mammoth one step closer toward its goal of low-cost, in-home molecular diagnostics for any illness. "The idea is we want to make this test so affordable that you can imagine going down to your CVS or Walgreens so you can bring this access to molecular level information [to questions like] if my kid has strep or flu before dropping them off to school."

See also: CRISPR-Cas14: a family of small DNA-targeting enzymes enabling high-fidelity SNP genotyping

Related (all involving Dr. Jennifer Doudna): The Rapid Rise of CRISPR
Compact CRISPR Systems Found in Some of World's Smallest Microbes
Nonviral CRISPR-Gold Editing Technique Fixes Duchenne Muscular Dystrophy Mutation in Mice
CRISPR Used to Cure Duchenne Muscular Dystrophy in Dogs... by Further Damaging DNA
CasX Protein Works for Gene Editing in Bacterial and Human Cells

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