Inside the laboratory, training of genome surgeons in the fight against the disease

Delaney Van Riper was exhausted. It was summer 2017 and she had spent the previous day visiting the campus on the cliff edge of the University of Santa Cruz, sorting out her papers and meeting some of her 4 000 other new slugs. Now dressed in sweat, she was ready to take a nap in the back seat to go to her family's home three hours away in Sacramento. But first she had to stop in a glass and granite building in Mission Bay, San Francisco, roll up her sleeves and give scientists that she had just met a few blood tubes drawn from the hollow of her arms.

While Van Riper spent the next year navigating new poetry courses for roommates and freshmen, researchers at the Gladstone institutes were reprogramming his blood cells into stem cells and then into neurons, making them grow in Incubators per million and sending Crispr systems to attempt an embarrassing mutation that lurks on the short arm of its longer chromosome.

Van Riper, 19 years old and major in literature, was born with a rare genetic disorder called Charcot-Marie-Tooth, or CMT, which slowly erodes the ability of her nerve cells to send messages between her brain and her muscles. Doing things with your hands and feet, like walking and holding a pencil, has become increasingly difficult. But last year, she became one of the few patients whose cells are currently undergoing experimental Crispr procedures at Gladstone, which could one day be used to rid them of their genetically determined disabilities.

In September, Jennifer Doudna, a biochemist at the University of Berkeley and a pioneer in the field of information technology, announced the opening of a laboratory across the bay to establish the 39, the epicenter of a whole new field of medicine: genomic surgery. While Crispr pharmaceutical companies are increasingly collecting capital and racing clinical trials, Doudna realized that it was possible for someone to adopt a broader and more more inclusive. She found a home for this at Gladstone, a non-profit biomedical research center of hundreds of scientists affiliated with UC San Francisco and its clinical programs. What she is contemplating is the development of procedures closer to the way surgeons cut malignant tumor tissue with a scalpel today. Except tomorrow, genome surgeons will use Crispr's molecular scissor function to eliminate or replace defective genes, healing diseases according to their genetic source code.

"We focus on what will be best for patients in the long run, not just the product we can quickly market," says Doudna. She is a co-founder of a number of Crispr-based medical companies, but is concerned that the pressures to quickly generate a profit will leave behind many rare genetic diseases, each caused by a constellation of unique mutations that all require custom tools. to repair them. And then there is the question of the affordability of the treatments that come to the market. Reducing the price to pay for patients and making Crispr a sustainable technology is easier to define in a non-profit setting, says Doudna. "We need to step back and find a way to ensure in the future that this technology is not only available at 0.1%."

Cost is not the only challenge. There is also the problem of getting Crispr in the right cells, and in enough of these cells to make the difference. You can teach cells to build Crispr systems themselves, with instructions routed by harmless viruses, but this approach makes it more difficult to control the cutting action of Crispr. You can convince Crispr to enter the cell directly by coating the protein complex itself with fat particles, but it is not very effective and is difficult to control. How will doctors provide gene editors to tissues inside the human body, such as the heart or the brain?

Then there are even more fundamental unknowns associated with the development of an entirely new medical modality. What is the right dose? What is the right way to calculate the risks and benefits for patients? What data do you need to collect to know that they are safe and effective? Doudna and his colleagues at Gladstone hope to answer these big questions in five to ten years. Their efforts may be the most concentrated effort in a national effort to create the tools and rules necessary for physicians to widely adopt genome editing as part of standard care for 25 million Americans living with HIV. one of the 6 000 diseases caused by a glitch their DNA.

In January, the National Institutes of Health committed $ 190 million over six years to accelerate Crispr's move to the clinic. To date, he has awarded grants to a consortium of 17 academic research institutions, including Gladstone, and a biotechnology company to help them assemble and release a Crispr toolkit. Among other things, it will include better delivery techniques as well as safer and more accurate genome publishers, as well as cell tracking technologies to verify results after surgery. Its components are intended, in part, to help the Food and Drug Administration chart a flexible regulatory pathway for Crispr to be treated as a hybrid technology: a device part (molecular scalpel), a drug part (bacterial protein) .

"Before it gets too far, we are trying to set standards for genome editing," says Todd McDevitt, principal investigator at Gladstone, who assesses the safety of Crispr in human cells and tissues. Unlike other types of drugs that you can test on model organisms, it is not possible to modify the human genome in a mouse or a rat. Before doctors can begin to inject Crispr into patients, scientists like McDevitt need to develop realistic microtissues to test.

Inside McDevitt's lab, one of his postdocs pulls out a plate with a few flesh-colored dots, the size of a felt-tip pen, floating in a bright pink paper bath. She slides it under an inverted fluorescence microscope. Immediately, two black spots fill the monitor nearby. A shock of green light shivers them. Seconds later, it happens again. Each organoid is about a year old and has about 100,000 human heart cells that are beating. In their DNA, a green fluorescent protein is only encoded in calcium. Each green flash on the screen represents a microscopic contraction of the heart ball and serves as a visual cue for any improvement (or damage) caused by Crispr.

In addition to cardiac organelles, McDevitt's laboratory cultivates retinal sheets and brain balls from cells donated by patients such as Van Riper. In addition to CMT, Gladstone is also focusing its initial efforts on two other genetic disorders – a heart condition called cardiomyopathy and the BEST disease, which causes progressive blindness. Over the next three years, as other building researchers design new Crispr systems, they send them to McDevitt. Then, his team will test them on their 3D organoids, each bearing the mutational signature of the person from whom it comes. They will measure both expected and unplanned consequences. The goal is to one day launch a clinical trial in which patients like Van Riper undergo surgery of the Crispr genome using synthetic products that have already been proven in their own cells.

"We are trying to perfect a trade," says Bruce Conklin, physician and principal investigator at Gladstone. "But the idea is to test a lot of hypotheses with a patient so that the next person is much faster."

Doudna explains that Conklin, a long-time collaborator, coined the term "genome surgery". Together, they envision a future in which a patient with TMC will enter a hospital, get his genome sequenced and the doctor will say, "OK, based on your mutations, you're running for Crispr A and Crispr B," which all been approved by the FDA for this disease, as well as Crispr C, D, E, F, and G. Together, this suite of genome publishers would cover every one of the thousands of different mutations that all cause CMT. "In a system like this, we could just give free Crispr systems," says Conklin. "And then it's just a procedure like an organ transplant. Nobody gets paid for an organ. "

But before that happens, Doudna and Conklin will have to raise a large sum to fund expensive clinical trials. And patients will have to volunteer to see if the Crispr that heals their cells in a dish and ball-shaped can do the same thing in their bodies. For Van Riper, this could possibly happen before the end of his studies. She says she's a little scared for that day, if he ever does it. "But someone has to do it, right?" She says. "I would not participate if I did not want to see it until the end."

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