Experts – about editing the genes of humans and pigs
On October 5, 2015, the National Academy of Sciences and the National Academy of Medicine of the USA held a seminar dedicated to the achievements of the research area devoted to human gene editing. The invited experts discussed modern approaches to editing human genes, their effectiveness, practicality and the likelihood of undesirable side effects, as well as manipulation of embryo genes and approaches to the treatment and prevention of genetic diseases in a historical context.
Ethical aspects, as well as issues of regulating the use of human gene editing were not discussed at this seminar, but they are included in the list of main issues that will be discussed at the international congress dedicated to this research area in Washington, scheduled for December 2015.
The International Congress, jointly organized by the US academies, the Chinese Academy of Sciences and the Royal Society of Science, is part of an important initiative to provide information on solutions for new and developing human gene editing technologies, such as CRISPR-Cas9. These technologies can form the basis of promising methods of treating serious diseases, but they also raise a lot of doubts, especially because of the possibility of using them to make changes in genes that can be transmitted to the next generations.
One of the topics discussed at the seminar was the achievement of geneticists from Harvard University, working under the guidance of Professor George Church, who used the CRISPR-Cas9 system to modify pig genes in order to improve the survival of pig donor organs in the human body.
Leading experts in this field expressed the following opinions about this interesting technique:
Professor James Murray, Department of Animal Sciences, University of California at Davis (USA):
"This is an excellent demonstration of the power of the CRISPR-Cas9 system, as well as an achievement I expected. The presence of endogenous porcine retroviruses (PERV) in pig genomes was a cause of serious concern and a limiting factor for the use of xenotransplantation. The CRISPR system provided a methodology for removing PERV and this work demonstrated the possibility of its effective application. This work also provides evidence of the possibility of making multiple changes simultaneously by destroying all 62 PERV inserts in parallel during a single procedure. Now it is necessary to apply this to cells created for xenotransplantation, as well as cloned animals designed to breed a line of pigs that do not have PERV."
Professor Bruce Whitelaw, Professor of Animal Biotechnology, Roslin Institute, University of Edinburgh (Scotland):
"The report of the Church group continued a series of achievements in the field of genome editing technologies. Their study, in which multiple genetic loci were simultaneously edited, is a major breakthrough compared to earlier reports describing the editing of individual target loci. In the work at the experimental level, an attempt has been made to solve the problem of xenotransplantation and, if the results are successfully reproduced in animals, it can become the next step towards achieving this biomedical goal. Perhaps more importantly, despite the fact that the report made by Yuhan Yang described editing multiple copies of the same DNA sequence, their achievement indicates the possibility of influencing many different sequences."
Dr. Sarah Chan, Chancellor's Fellow, Institute for the Study of Population Health and Informatics, University of Edinburgh, member of the Hinxton Group:
"This work is of particular scientific interest as an example of effective multiple gene editing (simultaneous modification of multiple genetic regions) on a larger scale than previously described. Of course, there is still a long way to go to overcome other problems associated with pig xenografts, and especially immune compatibility, and even in the case of overcoming scientific difficulties and safety problems, we should take into account possible cultural issues and social impact associated with the large spread of the use of pig organs for human transplantation. Nevertheless, the results of the study are of great value not only as proof of principle, but also as a potential step towards therapeutic achievements in this highly sought-after research area. Moreover, by demonstrating the possibility of using genome editing to remove unwanted genetic elements that may become a barrier to successful treatment, the study demonstrates the extensive scope of these technologies for a wide range of potential therapeutically suitable approaches, in addition to modifying the human genome."
An article by a group of scientists who worked under the leadership of J.Church, Luhan Yang et al. Genome-wide inactivation of porcine endogenous retroviruses (PERVs), published in Science.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the National Academies of Sciences, Engineering, and Medicine – Human Gene Editing Information-Gathering Meeting: Oct. 5 and Science Media Center – Expert reaction to study using CRISPR to produce pig organs suitable for xenotransplantation into humans.
14.10.2015