Scientists at China’s Shanghai Institutes for Biological Sciences are seeking to “cure” autism one monkey at a time, by creating transgenic primates with DNA genetically altered to make them develop an autism-like disorder. The idea, they stated is to enable them to better understand and treat people with the disorder, since “their brain circuitry is much closer to that of our own.”
“Once we know the brain circuits responsible, we can start intervening” in these disorders, for example, using noninvasive brain stimulation or gene therapy (a treatment that involves replacing missing or defective genes), study author Zilong Qiu said in a conference call with reporters last Thursday.
According to their report published yesterday in the journal nature, Qiu and his colleagues injected a virus containing multiple copies of the MeCP2 gene (methyl CpG binding protein 2), identified with Rett Syndrome, into the undeveloped eggs of macaque monkeys. The eggs were then fertilized and the resulting 53 embryos implanted into 18 female surrogate monkeys, 9 of whom got pregnant. Although 4 monkeys were stillborn, 5 female and 3 male transgender babies were born live. All of the infants had the duplicate MeCP2 gene. In a 2nd experiment, Qiu’s team implanted 105 embryos into 36 surrogate mothers. However, only 7 monkeys have birth to 9 babies, but only two survived.
Although the transgenetic monkeys did not appear to be less intelligent compared with the unmodified animals, they did exhibit certain abnormalities, such as a preference for reaching toward one side when presented with a reward, as well as “engaging in repetitive motions such as walking in circles, spent less time than normal sitting and interacting with the other monkeys.” They also showed signs of anxiety (all behaviors identified as signs of autism).
A further experiment then sought to determine whether the transgenic monkeys could pass on the genetic defect to their progeny. The scientists used sperm from one of the transgenic monkeys to fertilize eggs and implant them into 22 surrogate females. In the end all 5 babies born (including one stillborn) carried the MeCP2 mutation, and showed the same lacks in social interaction as their transgenic parent.
In the meantime, Huda Zoghbi, a professor at Baylor College of Medicine, who has studied the MeCP2 duplication syndrome in mice, told Business Insider that scientists need to be cautious about the findings, because the genes modified in he monkeys “ didn’t exactly mirror the effects of the human version of the disease, such as cognitive problems and seizures.”
“We need to develop criteria before generating a non-human primate model so that the model is as optimal as possible and it can be useful for pre-clinical research,” Zoghbi stated in an email. It should also be noted that Zoghbi was not personally involved with Qui’s experiments.
Note: MECP2 protein is found in all cells in the body, including the brain, and seems to be essential for the normal function of nerve cells.acting to either repress or activate several other genes depending on the circumstances.