June 5th, 2009
Journal of Virology
May 27, 2009
Deficiency of Niemann-Pick type C-1 Protein Impairs HIV-1 Release and Results in Gag Accumulation in Late Endosomal/Lysosomal Compartments
Tang Y, Leao IC, Coleman EM, Broughton RS, Hildreth JE.
Human immunodeficiency virus type 1 (HIV-1) relies on cholesterol-laden lipid raft membrane microdomains for entry into and egress out of susceptible cells. In the present study, we examine the need for intracellular cholesterol trafficking pathways with respect to HIV-1 biogenesis using Niemann-Pick type C1 deficient cells (NPCD) wherein these pathways are severely compromised, causing massive accumulation of cholesterol in late endosomal/lysosomal (LE/L) compartments.
We have found that induction of an NPC disease-like phenotype through treatment of various cell types with the commonly-used hydrophobic amine drug U18666A resulted in profound suppression of HIV-1 release.
Further, NPCD EBV-transformed B lymphocytes and fibroblasts from patients with NPC disease infected with a CD4-independent strain of HIV-1 or transfected with an HIV-1 proviral clone, respectively, replicated HIV-1 poorly when compared to normal cells.
Infection of the NPCD fibroblasts with a VSV-G pseudotyped strain of HIV-1 produced similar results, suggesting a post-entry block to HIV-1 replication in these cells. Examination of these cells using confocal microscopy showed an accumulation and stabilization of Gag in LE/L compartments. Additionally, normal HIV-1 production could be restored in NPCD cells upon expression of a functional NPC1 protein, and overexpression of NPC1 increased HIV-1 release.
Taken together, our findings demonstrate that intact intracellular cholesterol trafficking pathways mediated by NPC1 are needed for efficient HIV-1 production.
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