The cholesterol homeostatic protein Niemann‐Pick Type C‐2 (NPC2) is required for HIV‐1 assembly and release

Abstract

HIV‐1 utilizes host proteins for productive viral replication. It is well established that HIV‐1 buds from cholesterol‐rich microdomains called lipid rafts, and that cholesterol is required for HIV‐1 entry, infectivity, and structural integrity. NPC2 protein binds cholesterol with high affinity and regulates cholesterol efflux from the late endosomal/ lysosomal (LE/L) compartments. NPC2 mutations result in NPC disease (NPCD), a cholesterol storage disorder characterized by an accumulation of cholesterol in LE/L compartments. We hypothesize that NPC2 is required for HIV‐1 assembly and release. Our findings show that in the absence of functional NPC2, HIV‐1 release is decreased. In fibroblasts from NPC2‐deficient patients infected with VSVG pseudotyped HIV‐1, virus release is reduced by 80%. Moreover, HIV‐1 Gag accumulated in the cholesterol laden LE/L compartments of the fibroblasts. Lysosomal targeting of NPC2 is mannose receptor dependent. Addition of mannose 6‐phosphate to chronically‐infected Jurkat cells disrupts both lysosomal targeting of NPC2 and HIV‐1 egress. Similarly, siRNA‐mediated silencing of NPC2 in these cells inhibited virus release. Collectively, these data indicate that NPC2 is required for HIV‐1 assembly and release.Supported by NIH grant 5732HL‐007737‐15