HIV Tat protein increases Bcl-2 expression in monocytes which inhibits monocyte apoptosis induced by tumor necrosis factor-alpha-related apoptosis-induced ligand

Abstract

Objective: To investigate the effect of HIV Tat protein on Bcl-2 expression in human monocytes, and observe apoptosis of Tat-stimulated monocytes induced by TNF-α-related apoptosis-induced ligand (TRAIL). Methods: Western blot was used to detect Bcl-2 expression in monocytes stimulated by HIV Tat protein, and Annexin V and 7-AAD staining were used to detect apoptosis of monocytes induced by TRAIL. Results: HIV Tat protein increased Bcl-2 expression in human monocytes in a dose-dependent manner. Annexin V staining showed that 51.54% of monocytes underwent apoptosis after being treated with 100 ng/ml recombinant TRAIL. When monocytes were prestimulated with HIV Tat, only 15.46% of monocytes underwent apoptosis. This effect can be inhibited by polyclonal anti-Tat serum. 7-AAD staining showed similar results. Conclusion: HIV Tat protein increases Bcl-2 expression in monocytes which inhibited apoptosis induced by TRAIL. HIV Tat protein may play an important role in the mechanisms of HIV-persistent infection in monocytes. Copyright © 2007 S. Karger AG.