Finding could help scientists develop new drugs to slow progression of disease
Mount Sinai School of Medicine researchers have discovered that marijuana-like chemicals trigger receptors on human immune cells that can directly inhibit a type of human immunodeficiency virus (HIV) found in late-stage AIDS, according to new findings published online in the journal PLoS ONE.
Medical marijuana is prescribed to treat pain, debilitating weight loss and appetite suppression, side effects that are common in advanced AIDS. This is the first study to reveal how the marijuana receptors found on immune cells-called cannabinoid receptors CB1 and CB2-can influence the spread of the virus. Understanding the effect of these receptors on the virus could help scientists develop new drugs to slow the progression of AIDS.
"We knew that cannabinoid drugs like marijuana can have a therapeutic effect in AIDS patients, but did not understand how they influence the spread of the virus itself," said study author Cristina Costantino, PhD, Postdoctoral Fellow in the Department of Pharmacology and Systems Therapeutics at Mount Sinai School of Medicine. "We wanted to explore cannabinoid receptors as a target for pharmaceutical interventions that treat the symptoms of late-stage AIDS and prevent further progression of the disease without the undesirable side effects of medical marijuana."
HIV infects active immune cells that carry the viral receptor CD4, which makes these cells unable to fight off the infection. In order to spread, the virus requires that "resting" immune cells be activated. In advanced AIDS, HIV mutates so it can infect these resting cells, gaining entry into the cell by using a signaling receptor called CXCR4. By treating the cells with a cannabinoid agonist that triggers CB2, Dr. Costantino and the Mount Sinai team found that CB2 blocked the signaling process, and suppressed infection in resting immune cells.