Gelsolin segment 5 inhibits HIV-induced T-cell apoptosis via Vpr-binding to VDAC.

Viral protein R (Vpr) from the human immunodeficiency virus induces cell cycle arrest in proliferating cells, stimulates virus transcription, and regulates activation and apoptosis of infected T-lymphocytes. We report that Jurkat cells overexpressing full-length gelsolin show resistance to Vpr-induced T-cell apoptosis with abrogation of mitochondrial membrane potential loss and the release of cytochrome c. Co-immunoprecipitation assays in HEK293T cells demonstrated that overexpression of full-length or segment 5 (G5) but not G5-deleted gelsolin (DeltaG5) bound to the voltage-dependent anion channel (VDAC), and that the G5 subunit can inhibit HIV-1-Vpr-binding to VDAC. We also confirmed that full-length gelsolin has the same effect in Jurkat cells. Clonogenic analysis showed that transfection of G5 but not DeltaG5 cDNA protects Jurkat T cells from HIV-Vpr-Tet induced T-cell apoptosis and promoted cell survival, as did full-length gelsolin. These results suggest that the gelsolin G5 domain inhibits HIV-Vpr-induced T-cell apoptosis by blocking the interaction between Vpr and VDAC, and might be used as a protective treatment against HIV-Vpr-induced T-cell apoptosis.