Chinese and American researchers involved in the use of the CRISPR-Cas9 gene mounting to change the embryo DNA for seven couples in China are under investigation. The work has also received almost universal condemnation around the world.
He jiankui, who led the research, is a researcher at Southern University of Science and Technology of China in Shenzhen. He studied at Rice University in Houston and Stanford University before returning to China. One of his teachers at Rice was Michael Deems, who worked with He Jiankui on the project in China and holds a small stake in two commercial genetics companies launched by He Jiankui.
Rice University announced after the announcement of the opening of a "thorough investigation" of Deems involvement. In a statement, Rice University said it was unaware of the research in advance and that "wherever it was conducted, this work described in the press reports violates the guidelines. scientific conduct and are contrary to the ethical standards of the scientific community and Rice. University."
He Jiankui and his research are also affiliated with Shenzhen Harmonicare Hospital for Women and Children. After the announcement of the new, South University of Science and Technology denounced research, issuing a statement saying that it was "a serious violation of ethics and academic standards".
The University of the South also claims to have no knowledge of the project and is launching an investigation by an independent committee. He Jiankui had started a three-year absence from university in February.
What He Jiankui and Deems did is use CRISPR gene editing on human embryos to disable a gene called CCR5. This gene creates a protein that allows HIV to enter a cell. All men in the seven couples were HIV positive and women were not. The goal of gene editing was not to prevent HIV transmission, He said, as the seven male HIV infections were strongly repressed by conventional anti-HIV drugs.
The CRISPR revision was performed during in vitro fertilization (IVF). Sperm has been "washed" to separate it from sperm, where HIV is present. Then, only one sperm was inserted into a single egg to create an embryo. Then, the CRISPR-Cas9 gene editing tool was applied.
When the embryos were 3 to 5 days old, several cells were examined for editing. At that time, the couple could choose to use published or unedited embryos for their pregnancy attempts. In total, 16 of the 22 embryos were edited and 11 were used in six implant attempts.
He Jiankui announced the search and apparently successful birth of twins, Lulu and Nana, from a group of parents. The announcement was made at an international conference on gene editing held in Hong Kong. The research was not published in a peer-reviewed technical journal, although some researchers did review the work.
This announcement, which is a scientific milestone, is also deeply troubling. Ethicists called it "monstrous", "inconceivable" and "a serious violation of human rights".
More than 100 Chinese scientists sign a letter condemning the research. In part, the letter said: "The approval of bioethics for this so-called" study "was insufficient. We can only use the word "crazy" to describe the experiment conducted directly on human beings. Within the scientific community, we have a lot to debate about the accuracy and out-of-target effects brought by CRISPR. Any attempt to alter human embryos and impose enormous risks on infants carries considerable risks without a strict prior examination. "
Paula Cannon of University of Southern California, who is participating in clinical trials that shut down CCR5 as a way to treat HIV, said L & # 39; Atlantic, "Was it a reasonable thing to do? I would categorically say no. The idea that being born sensitive to HIV, which is the vast majority of humans, is sort of a disease that requires the extraordinary intervention of gene editing shocks me. I feel he appropriates this potentially valuable therapy as a shortcut to doing something in the field of genetic modification. He is either very naive or very cynical. "
Cannon and other clinical trials using CRISPR are underway in the United States and Europe, but are not conducted on embryos. They are performed in the cells of adults with specific diseases.
Michael Snyder, Director of Stanford University's Center for Genomics and Personalized Medicine, held a meeting with the Los Angeles Timesand noted, "What would have been done in China is called germ line modification. It makes changes to the reproductive cells that would be passed on to future generations. This is potentially more important than introducing a gene change in a single individual. It is therefore all the more important to understand the risks downstream of gene editing. "
The main risks are the untargeted effects that genetic changes may have affected other areas of the fetal genome, with unintended consequences. In addition, although rare, people born without the CCR5 gene do not seem to have any adverse effects, but the complete functioning of the gene is not understood.
Snyder also pointed out that a safer approach, doing the same job, would have been to alter the CCR5 gene in the adult. "You can actually take a person's cells at risk for HIV infection and change them. You do not have to do it in the embryo. "
The fundamental conclusion for most researchers is that this research on human embryos was both medically unnecessary and scientifically premature. Snyder points out that when in vitro fertilization was introduced, it was very controversial, but is now commonplace. He also added that if the children had negative side effects – and at that time, only one of the girls seems to have completely managed to extinguish both copies of the CCR5 gene, which has not yet been verified – it could put the whole field back. as well as health problems for girls.
"It happened years ago when gene therapy was very young," Snyder said. "In one of the first experiments, the patch affected the genes responsible for cell proliferation, thereby causing cancer."