Friday , October 22 2021

Biologist plans to produce more babies edited by CRISPR – "I think I'm crazy enough to do this"



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Last November, the scientific field was confronted with an unexpected announcement by Chinese scientist Jiankui He, who claimed to have genetically edited two human embryos. The announcement was received with global condemnation and frustration that Jiankui had done with such work in the absence of ethical approval from the authorities, and with the known risks associated with the genetic editing: "They jumped the gun for a good 10 or 15 years and in a field like human reproduction is actually very risky, "said biologist and author Nessa Carey.

There was a subsequent race between the authorities to impose a legal and ethical framework for genetic editing experiments to ensure their safety and justification, and until that happened any new experiments of this kind were called to be banned. However, it seems that these harsh warnings did not dissuade all scientists.

An article published yesterday in Nature outlined the intentions of Denis Rebrikov, a molecular biologist from Russia, to produce babies with modified genes, making him the "second" Jiankui He. Rebikrov is the head of a genome-editing laboratory at Russia's largest fertility clinic, the Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology in Moscow and is a researcher at the Russian Research University of Pirogov, also in Moscow. Recognizing that if he chose to do this before Russia updated its regulations on gene editing, it would be breaking the law, he replies, "I think I'm crazy enough to do that."

Jiankui He used the CRISPR-Cas9 tool to create a specific mutation in the CCR5 gene that encodes a protein used by the human immunodeficiency virus (HIV) -1 to enter cells. This mutation CCR5Δ32, is transported naturally by some individuals and may confer innate resistance to HIV-1. Although recent research suggests that the malfunction of this gene is linked to a higher rate of mortality, Rebikrov aims to achieve exactly the same gene.

Jiankui He has chosen to modify the CCR5 gene in embryos that were raised from parents with HIV. In contrast, Rebirov plans to CCR5 gene in embryos that will then be implanted in HIV-positive mothers, thus reducing the risk of passing the virus to the baby in the uterus. According to the article, Rebrikov already has an agreement with an HIV center in the city to recruit HIV-infected women for the experiment.

One of the inventors of CRISPR, Jennifer Doudna, expressed her concerns about the biologist's plans for Nature: "The technology is not ready," she says. "Not surprising, but it's very disappointing and disturbing."

Interview with CRISPR pioneer Jennifer A. Doudna

Rebrikov anticipates that the Ministry of Health will clarify the rules on the clinical use of embryo genetic editing in the next nine months. The article states that in order to avoid punishment for the experiments, he first intends to seek the approval of three government agencies, which may take between one month and two years.

A major concern associated with genetic editing technologies, such as CRISPR, is the possibility of off-target effects, resulting in unintended changes in the genome – the consequences of which can not be fully anticipated. Efforts to refine these technologies and improve their specificity are in progress, but so far a "gold standard" technique is not available.

Rebrikov claims that he is developing a technique that can ensure that there are no mutations out of target, and plans to post preliminary findings online within a month, but Doudna declares skepticism here: "The data I've seen say that it is not so easy to control the way the DNA repair works. "

The documentary on the Wild Code movie led CRISPR filmmakers and scientists to China, where they were the first to find the world's attention to the work of Jiankui He. Read more about documentary and genetic editing in China here.

Reference: David Cyranoski. 2019. The Russian biologist plans more babies edited by CRISPR. Nature. doi: 101038 / d41586-019-01770-x.

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