Protecting cells from HIV
12 Apr 2012 by Evoluted New Media
The protein SAMHD1 protects cells from infection by HIV, and researchers hope to harness its protective mechanism to develop therapeutic approaches aimed at slowing the virus’ progression to AIDS.
When HIV infects a cell, it hijacks its molecular material – deoxynucleotide triphosphates (dNTPs) – to replicate. Once replicated, the resulting DNA molecule contains all the genes of the virus and instructs the cell to make more virus.
Researchers from NYU Langone Medical Centre found that cells containing SAMHD1 are protected from hijacking. It protects the cell by destroying the pool of dNTPs – meaning the virus has no building blocks to make its genetic information.
“The virus enters the cells and then nothing happens,” said Dr Nathaniel Landau, professor of microbiology. “It has nothing to build and replicate with, so no DNA is made.”
As a result, the most common form of HIV does not readily infect these cells. Instead it replicates in CD4 T-cells, which do not contain SAMHD1 and therefore have a healthy pool of dNTPs. Landau said the virus has evolved in such a way that it may deliberately avoid trying to infect immune cells with SAMHD1 to avoid alerting the greater immune system.
“Viruses are remarkably clever about evading our immune defences,” said Landau. “They can evolve quickly and have developed ways to get around the systems we naturally have in place to protect us.”
“It’s a bit of evolutionary warfare and the viruses, unfortunately, usually win. We want to understand how the enemy fights so that we can outsmart it in the end.”
Understanding how SAMHD1 provides protection to cells may provide a new idea about how to stop or slow the virus’ ability to spread. Future research may focus on finding a way to increase the amount of SMAHD1 in cells where it doesn’t exist, or reduce the number of dNTPs in cells vulnerable to infection.
