vGPCR-Mediated ANO1 Modulation of Apoptosis Regulates Lytic KSHV Infection.

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that causes Kaposi's sarcoma (KS), an endothelial cell-derived malignancy that primarily affects immunocompromised individuals. During lytic reactivation, KSHV expresses viral proteins that promote viral replication and modulate host signaling pathways. Here, we identified the calcium-activated chloride channel ANO1 (TMEM16A) as a previously unrecognized host factor induced by the KSHV lytic protein vGPCR. RNA sequencing, RT-qPCR, and immunofluorescence analyses demonstrated robust ANO1 upregulation in vGPCR-expressing endothelial cells and during KSHV lytic reactivation. siRNA-mediated depletion of vGPCR significantly reduced ANO1 expression, demonstrating that vGPCR contributes to ANO1 induction during infection. Functionally, ANO1 knockdown sensitized vGPCR-expressing endothelial cells to caspase-dependent apoptosis under serum-starved conditions, which was rescued by the pan-caspase inhibitor Z-VAD-FMK. In reactivated iSLK.BAC16 cells, genetic or pharmacological inhibition of ANO1 increased late apoptosis, enhanced KSHV lytic gene expression, and promoted infectious virion production. Together, these findings identify ANO1 as a vGPCR-regulated host factor that promotes cell survival and modulates KSHV lytic replication, highlighting ANO1 signaling as a potential therapeutic target in KSHV-associated disease.