New "gene scissors" can remove immunodeficiency virus genes

BEIJING, Dec. 2 (Xinhua Feng Weidong) According to a new study published online in Nature Communications, U.S. scientists have successfully edited SIV (monkey immunodeficiency virus, which is closely related to the human immunodeficiency virus HIV, or the cause of
) from the genomes of non-human primates. The breakthrough is an important
in the study of hiv viruses and will bring researchers closer than ever to developing treatments for HIV infection in humans."For the first time, we have demonstrated that a single inoculation of a CRISPR gene-edited construct carried by adeno-related viruses can edit the SIV genome from infected cells in rhesus monkeys," said researchers at the University of Tamp School of Medicine, where
led the study.
The new work shows that gene-edited building blocks developed by the team can reach infected cells and tissues, known as SIV and HIV virus reservoirs, cells and tissues that have been integrated into host DNA for years and are a major obstacle to curing infection. SIV or HIV in these virus libraries is beyond the scope of antiretroviral therapy, which inhibits virus replication and removes the virus from the blood. Once antiretroviral treatment is stopped, the virus appears from its reservoir and replicates again.
in non-human primates, SIV behaves very much like HIV. The SIV-infected rhesus monkey model studied in the laboratory is an ideal large animal model that can sum up HIV infection in humans.
the new study, researchers designed the SIV-specific CRISPR-Cas9 gene-editing construct. Cell culture experiments have confirmed that the editing tool can cut integrated SIV DNA from the correct location of the host cell DNA. They then loaded the build into adeno-related virus 9 (AAV9) vector, which can be injected intravenously into animals infected with SIV.
the researchers randomly selected three SIV-infected macaques, each receiving an AAV9-CRISPR-Cas9 injection, and another macaque as a control. Three weeks later, the researchers collected blood and tissue from macaques. The analysis showed that in macaques treated with AAV9-CRISPR-Cas9, gene-editing constructs were distributed to a wide range of tissues, including bone marrow, lymph nodes and spleen, and reached a very important viral library of CD4-T cells.
, researchers at Tamp University performed genetic analysis of treated animal tissue to prove that the SIV genome can effectively be cleavaged from infected cells. Lysation efficiency varies from tissue to tissue, but is significantly higher in lymph nodes.
researchers say this is an important step in the process of ending the
virus, and the next step is to evaluate the treatment over a longer period of time to determine whether the virus can be completely eliminated and even free subjects from antiretroviral therapy.