This month, Denis Rebrikov went to the old Moscow mansion, which today houses the Institute of Philosophy of the Russian Academy of Sciences, to meet with critics and dot the i's.
Rebrikov was a respected but little-known geneticist at Pirogov Russian National Research Medical University when an article appeared in Nature in June about his controversial plan to alter the DNA of a human embryo using powerful CRISPR editing technology (short polyyndromic repetitions, regularly arranged in groups), and then transplant it into the uterus, so that a child turns out from this embryo. Subsequently, Rebrikov attracted the attention of the whole world, and his actions were condemned in Russia and other countries, calling the scientist a reckless self-promoter.
At the beginning of the meeting, which was attended by bioethics specialists, geneticists and medical doctors, Rebrikov lamented that the audience wanted to discuss the merits of his proposed experiment before he had the opportunity to talk about it in detail. “People are discussing my thoughts and my intentions as if I am not here,” the scientist said. “In Russia we have a saying: 'I haven’t read Pasternak, but I have my own opinion about him,” he added, referring to the author of Doctor Zhivago. "This is my case."
Rebrikov's outrage stems from negative attitudes towards Chinese scientist He Jiankui, who stunned the world last November when news broke that he had secretly edited a human embryo with CRISPR in an attempt to make it stable. to HIV, and then transplanted it into a woman's uterus, resulting in twin girls. He has been subjected to rigorous law enforcement scrutiny, but the girls are not in any immediate danger that outweighs the potential harm from editing.
As a result of his amateur performance, He lost his job at the university, he was kicked out of the biotech company he created, and the authorities are now investigating his case. The experiment also prompted new calls for a moratorium on any further editing of the germ line, that is, on making changes to DNA that could be passed on to future generations. This is what He did, and this is what Rebrikov wants to do with his genome editing. Two high-level commissions were created with representatives from several countries (but not from Russia), and they began to study the ethical side of such work, as well as issues of its regulation.
But unlike He, Rebrikov speaks openly about his intentions. He wants serious ethical and regulatory review to be done. He intends to use this method to treat hereditary deafness, citing a medical necessity that seems more compelling than the theoretical needs He selected. According to Rebrikov, he has a detailed scientific plan for assessing the risks of changing embryos using CRISPR, and only after such an assessment will he attempt to transfer them. And if He has no experience in the field of reproductive medicine, then Rebrikov is the chief geneticist of the country's largest state clinic of in vitro fertilization (IVF).
Rebrikov's critics have put forth a lot of arguments about his motives, claiming that he needs fame and notoriety, grants for the institute, recognition that Russian scientists are doing the most advanced research, and the relaxation of tight regulatory control that exists in the country in many ways. This stocky 43-year-old scientist, who in the past has won championship titles in sambo, as Russian martial arts, which combines judo and wrestling, are called, skillfully avoids these accusations and attacks. He calls them speculation and in response he laughs briefly or shrugs in bewilderment. Rebrikov stresses his belief that editing germline DNA brings great hope to people. “When I see a new technology emerging, I want to know how it works and how I can improve it. I do research at such a speedwhich is provided by natural biological factors”, - says the scientist.
Some reputable Russian researchers who are well acquainted with Rebrikov openly support his efforts. Molecular biologist Sergei Lukyanov, head of the Pirogov Medical University, who was Rebrikov's scientific supervisor when he wrote his thesis, and often collaborates with him, agrees that it is still premature to edit the embryo. But he supports Rebrikov's step-by-step approach: “Rebrikov is one of those who are trying to correct any imperfection of the universe, which, from his point of view, can be corrected. For him, this is an opportunity to give parents happiness to have healthy children."
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Rebrikov reacts calmly to sharp criticism. “People are usually very conservative, and that's okay,” he says. And he has a high degree of risk tolerance when there is a significant win at stake. “At the sports school we were taught to win without thinking about the scale of the problem,” the scientist says.
He suspects that in opposition to him are those numerous scientists who are religious. “It's strange to me when people believe in God and do DNA experiments,” he says, noting that they have “cockroaches in their heads”. This is such a Russian phrase that means that a person is confused or mistaken.
But critics, even having familiarized themselves with the details of his plans during the meeting, believe that these are cockroaches in his head. “The clinical use of genomic editing is like taking something out of thin air, it’s something imaginary,” said Sergei Kutsev, who heads the Moscow Medical Genetic Research Center and is the chief adviser to the Ministry of Health on genetics, at the meeting. Kutsev expressed doubt that Rebrikov did the right thing by targeting deafness mutations. He argued that the risk of causing harm by germline editing with CRISPR was too great. “I, like any other doctor, am absolutely sure that this technology is not ready,” Kutsev said.
Rebrikov recognizes the scientific consensus that draws a bright red line, prohibiting editing of embryonic DNA, because the new CRISPR technology is not immune to errors. But despite the dissatisfaction of many colleagues, he is almost on the very red line with both feet. And he calls on Russia and the world as a whole to answer the key question: how exactly can we responsibly cross this line?
Cowboy or cautious scientist?
For the first time, Rebrikov spoke about editing embryos in October 2018 at a conference in Kazan dedicated to "post-genomic" technologies. It was almost a month before the world knew about He's work. “It came as a complete surprise to me how fluently he spoke on this topic in a crowded hall for 500 people,” said Yegor Prokopchuk, a genomics specialist who works in Moscow at the Russian Academy of Sciences' Biotechnology Research Center. While Rebrikov's research does not violate Russian norms and rules, Prokopchuk still believes it is on the verge of what rigorous science and the Ministry of Health allow.
Working with non-viable embryos taken from his IVF clinic, which is part of the Kulakov Scientific Center for Obstetrics, Gynecology and Perinatology, Rebrikov and colleagues used CRISPR to create a deletion of a portion of the CCR5 gene located on the surface of white blood cells. People who naturally inherit the CCR5 gene from both parents have a high degree of resistance to HIV and do not suffer much from a lack of protein. This is the same gene that He tried to destroy in twin girls. But Rebrikov's experiment (about a dozen papers have been published to date on editing the human embryo, mostly by Chinese researchers) was a routine test of CRISPR's effectiveness. He did not tell the audience about transplanting edited embryos. “Everyone was interested in the technical details and no one asked questions about ethics,”- says Prokopchuk.
However, in February, Rebrikov told Prokopchuk and his medical students that his ambitions were more serious. Rebrikov and his colleagues had previously written in the Bulletin of the Russian State Medical University an article about his research on CCR5, because of which Prokopchuk invited him to the student club to discuss He's work and experiment. “Rebrikov insisted that he wanted to create children with revised CCR5 and that it would protect them from mothers' HIV infection,” says Prokopchuk, who has spoken out and still opposes such plans.
According to Rebrikov, from the very beginning he was not interested in the prevention of any particular disease. He wants to prove that it is safe to help people by editing gametes (sex cells). Rebrikov believes that such a technique will find wide application in the future. He wants to prove his assumptions by finding people with rare medical conditions that justify the risk. For example, he hopes to find HIV-positive women who want to have children but are immune to commercially available antiretroviral drugs, which significantly reduce the risk of mother-to-child transmission. Using IVF to create embryonic homozygotes for the CCR5 mutant could theoretically help prevent the mother from infecting the baby.
Rebrikov's first experiments with embryos using CRISPR technology aimed to better assess risks and problems. Ideally, when CRISPR is applied immediately after fertilization of the egg, the required editing will take place at the level of the unicellular zygote. Therefore, when the division process begins, all cells will be corrected. But if CRISPR is applied at the two-cell stage or later, some of the cells in the born child will have the required changes, and some will not. Such a mosaic child will not be protected from HIV. But of eight embryos edited using CRISPR, Rebrikov's team found signs of mosaicism in only three at the blastula stage, when the embryo is only five days old, and contains about 250 cells. However, scientists have not analyzed the equally dangerous possibility that editing will lead to the creation of random,off-target mutations. In theory, such mutations could cause cancer or other health problems. Rebrikov's work did not arouse much interest, since Chinese researchers published a similar study two years earlier, and the Bulletin of the Russian State Medical University is not widely known.
And only when an article about Rebrikov's work was published in Nature magazine, writing that he hoped to inject an edited embryo into the womb in the next six months, his plan attracted everyone's attention. Leading foreign scientists and bioethics experts condemned Rebrikov's intentions, calling them "irresponsible", "alarming" and "slippery slope." They argued that this "cowboy" had "weak data" and that he was just trying to get attention. Rebrikov dismisses accusations that he is trying to publicize his plans and emphasizes that he did not seek media attention. “If someone calls me and asks if I’ll answer his questions, I’ll say, 'Okay, why not,” the scientist says, noting that he has almost completely stopped responding to media requests.
But this attention led to a meeting in July, initiated by Prokopchuk and organized by Kutsev. “It seemed strange to me that the Russian scientific community did not react to this at all,” says Prokopchuk. To his surprise, among the 10 participants was the children's endocrinologist Maria Vorontsova. Many call her the daughter of Russian President Vladimir Putin, though no family member confirms this. (Putin declares his privacy to be kept secret, but admits he has daughters and grandchildren.) Vorontsova's presence led to a September 29 Bloomberg article titled "The Future of Genetically Modified Children in Putin's Hands." The agency noted that the meeting was "secret" and, rather unsubstantiated, stated that Vorontsova could influence Putin's stance on editing embryos.which, in turn, will determine the future of this direction. “The meeting was not secret,” said Igor Korobko, a geneticist from the Ministry of Health, who was present. “We also have rules and laws. This is not a presidential decision."
Detailed plan
Rebrikov could not find an HIV-infected woman who is not responding to antiretroviral drugs and wants to become pregnant. Therefore, he recently switched to another direction and began to look for hard of hearing homozygous pairs with the 35delG mutation in the gene GJB2, which encodes a protein of intercellular channels that help move chemicals like potassium between cells, including in the inner ear. The 35delG mutation, in which a single abnormal DNA backbone damages the protein encoded by the gene, is one of the most common genetic causes of hearing loss. Rebrikov wants to use CRISPR to replace the abnormal piece of DNA with the correct one.
The scientist told Science magazine that he intends to conduct a large number of safety checks before receiving permission to insert the edited embryo. First, he wants to sequence the entire genomes of both parents in order to obtain the initial data for the analysis of off-target (side) mutations in their edited embryos. Then Rebrikov wants to stimulate the woman's ovaries, get about 20 eggs, fertilize them with his partner's sperm, and finally correct the mutation with CRISPR. He will grow embryos for five days. By this time, they will have about 250 cells, and they will be at the blastula stage. Then he will take 10 of these blastulae and repeatedly sequence their genomes in order to identify any mutations that differ from the genomes of the parents.
If the number of new mutations is within the range normally found in unedited embryos (about 100 per embryo), then he will proceed to the next stage with the rest of the edited embryos. This will be the pre-implantation test, which is usually done in IVF. In this analysis, five to seven cells are taken from the embryo at an early stage of development and their genomes are analyzed. Rebrikov will test cells for many types of genetic defects, as well as mosaicism. But there may be other cells in the blastula that have unaltered GJB2 genes or untargeted changes. “We will always have certain technological limitations,” says Rebrikov.
With the help of a Moscow clinic for the hearing impaired, Rebrikov this summer found five deaf homozygous couples with the 35delG mutation, in which children will certainly be deaf. With one he has already met - although the husband and wife have not yet decided whether they will participate in his experiment.
Some practitioners and hearing loss scholars believe that such couples should not accept the risks associated with editing their fetuses. First, many of these people with the 35delG mutation have only mild hearing loss. They also point out that there is a proven alternative, a cochlear implant, which is an electronic device that stimulates the auditory nerves. It can partially restore hearing and has a special effect when young children undergo surgery. People with the 35delG mutation “do very well with cochlear implants,” says otolaryngologist Richard Smith, a research scientist at the University of Iowa. Smith and others question Rebrikov's decision to focus on deafness.because some people with hearing loss do not consider themselves disabled. Smith says he would choose something "less lethal."
David Corey, a neuroscientist at Harvard Medical School in Boston who studies the molecular basis of hearing loss, notes that some biotech companies are trying to develop treatments to help correct mutations in babies after birth. “If I were a parent, I would wait for gene therapy that only works on damaged cells,” he says.
Rebrikov counters that the decision should be made by potential parents who are properly informed about the risks. “How do they rate the quality of life of their children?” He asks. “Of course, hearing is not a matter of life or death, but parents can say,“Well, we really want our child to hear.”
Bioethics specialist Pavel Tishchenko, who works at the Institute of Philosophy of the Russian Academy of Sciences and who organized a meeting with Rebrikov this month, strongly opposed the idea at this meeting. “Parental consent alone is not enough for many reasons,” he said. - What will you tell your parents? The whole truth or only a part? Would they know, Tishchenko Rebrikov asked, what the World Health Organization's expert committee called premature germ line editing? And what did the group of eminent scientists who wrote the Nature article say the same? (Rebrikov says his information documents will be publicly available.)
Tishchenko asked if Russian society was ready for germline editing. He is worried that government regulators will not subject Rebrikov's proposal to rigorous and critical scrutiny. At the meeting, he said that the Ministry of Health has a competent ethics committee, but he has much less confidence in regulatory structures at other levels in Russia. “We have many ethics committees that will say yes to any innovation,” Tishchenko said.
And there is also the most important question, he said. Who should be held accountable if the child suffers from an unfortunate outcome? Rebrikov believes that if the regulatory authorities give the go-ahead for the experiment, but something goes wrong, the scientist should be released from responsibility. However, Tishchenko remembered a story about a man who threw a spear at a sports event in Ancient Greece and killed a spectator. “Who is responsible? The one who threw the spear or the organizer of the competition?”He asked. "This question remains unanswered to this day."
It will take a long time to resolve such important issues. But will the experiment proposed by Rebrikov allow us to find out at least how safe it is to edit germline DNA? The editorial staff of Sines spoke to several scientists with DNA sequencing experience, asking them about Rebrikov's plan to look for random consequences in blastulas. Every single one said that his team was likely to miss a lot of CRISPR-induced mutations.
Noticing such unintentional editing is “very difficult,” says Fyodor Urnov, director of research at the Institute for Innovative Genomics at the University of California at Berkeley, who opposes editing the human fetus even for scientific purposes. Even with the most advanced sequencing equipment, which Rebrikov says he will use, the latest bioinformatics will be needed to detect rare mutations in 250 blastula cells. Russian-born Urnov says that if Rebrikov can develop the necessary optimized computational algorithm for comparing embryonic genomes with parental genomes and for detecting mutations, it would be "an impressive achievement."
Urnov notes that other research teams that have edited human embryos with CRISPR have identified a dangerous level of off-target mutations. If Rebrikov finds a convincing way of identifying such mutations and finds out that they are few in number, will Urnov change his point of view on germline editing? “Yes,” he says. "Because now my confidence level is zero."
Starting a conversation
The day before the meeting at the Institute of Philosophy, the Russian Ministry of Health broke what many believed was a curious silence over germline editing. "The granting of permits for editing the human genome in clinical practice would be premature and irresponsible today," the ministry said in a statement to the media. It further notes that this is consistent with the opinion of the WHO expert committee on editing the human genome. Korobko, who heads the ministry's Department of Science, Innovation Development and Management of Biomedical Health Risks, said the announcement was in response to yet another media article about Rebrikov's plans that appeared in the influential Russian newspaper Kommersant.
According to Korobko, from a legal point of view, Rebrikov's work should not violate the current regulatory rules for in vitro fertilization, according to which the creation of embryos for research purposes is illegal. But now "it is not prohibited." Previously, Rebrikov conducted his research on discarded IVF embryos, and his future work will not be strictly fundamental research, but rather become a clinical trial, the goal of which is to help couples have healthy children. However, Korobko doubts that the ministerial ethics committee will approve clinical trials for editing germline DNA. “The WHO recommendation means a lot for the Russian Federation,” he said.
The RAS has not yet spoken out publicly about editing the human embryo, although many academies of sciences around the world call such editing premature. One of the reasons for this silence may be that many Russian scientists did not take Rebrikov's statements seriously. “When I first heard about this proposal, I thought it was a bad joke, because in our country research is overregulated,” said psychiatrist Raul Gainetdinov, who heads the Institute of Translational Biomedicine at St. Petersburg State University. - We are constantly stumbling. We cannot push anything through the Ministry of Health. Gainetdinov adds that there are very few laboratories in Russia that edit embryos even on animal models.
Bioethics specialist Elena Grebenshchikova, who works at the Institute for Scientific Information for Social Sciences, told the participants in the Moscow meeting that she was glad to see how Rebrikov brought these issues to the public arena. “There is no connection between scientists and society,” she said. "His openness on this topic is actually a big plus, which allows him to remove responsibility from a simple scientist or institute, and make it a collective responsibility with the involvement of the whole society."
Rebrikov is tired of the excited media, some of which completely misrepresent his work and plans to the audience. Answering the question of when he will be ready to request permission to transfer the edited embryo, the scientist does not name any timeframe: "This is a very strange question, because we do not make children, we just follow the scientific path."
Jon Cohen