An impressive progress has been made in modern medicine and especially in the treatment of HIV.   A team of scientists in Japan has successfully deleted human immunodeficiency virus-1 (HIV-1) genes from infected cells using the CRISPR/Cas9 gene editing system. That way, the HIV virus can successfully be blocked from replicating inside infected cells. HIV-1 infection is a chronic disease affecting more than 35 million people worldwide. Years ago, infection with HIV would almost certainly lead to developing AIDS, but treatment can now keep the disease at bay by antiretroviral therapy, but there is still no cure. Even with daily antiretroviral therapy (ART), the pathogen continues to hide in a patient’s cells. Researchers from Japan’s Kobe University used CRISPR/Cas9 to remove two regulatory genes of HIV-1 – which causes 95% of HIV infections – within infected human cell lines, and so stop further production of the virus. This technology is based on a bacterial antiviral system, but scientists have learned how to use it to precisely snip DNA in living cells.

‘Based on the rapid advances being achieved in CRISPR/Cas9 research, a HIV-1 functional cure may soon be within reach,’ the researchers note in their paper published in Scientific Reports.

“These results show that the CRISPR-Cas9 system, by targeting the regulatory genes of HIV-1, tat and rev, is a promising method for treating HIV infection,” comments co-author Masanori Kameoka, Ph.D., an associate professor at Kobe University Graduate School of Health Sciences. “We now need to investigate how we can selectively introduce a CRISPR-Cas9 system that targets HIV-1 genes into the infected cells of patients.”

Although advances have meant that HIV has gone from being a deadly disease to a chronic condition manageable with drug treatment, there is no cure as the virus can sit in dormant reservoirs within cells. The team focused on stopping these viral reservoirs from reactivating and proliferating by using genome editing to target HIV-1 genes, tat and rev, which are crucial for the dormant virus to replicate. This was repeated in each of the six major subtypes of HIV-1.

The method successfully blocked the production of tat and rev proteins, and consequently production of the virus. The team said there were also no off-target effects seen from the genome editing, and it did not affect the survival of the cultured cells.

“These results show that the CRISPR/Cas9 system, by targeting the regulatory genes of HIV-1, Tat and Rev, is a promising method for treating HIV infection,” said Associate Professor Masanori Kameoka of the Kobe University Graduate School of Health Sciences, Japan, who led the study. “We now need to investigate how we can selectively introduce into the infected cells of patients a CRISPR/Cas9 system that targets HIV-1 genes. In order to safely and effectively introduce the CRISPR/Cas9 system, the vectors must be improved.”, he added