HIV and Alcohol Synergistically Disrupt Lysosomal Function in Hepatocytes, Driving Extracellular Vesicle Release and Liver Injury

Abstract

Although the etiologies of hepatic complications among people living with HIV who consume alcohol are multifactorial, alcohol remains a relatively understudied contributor to the progression of HIV-related liver injury. Here, we investigated whether metabolically derived acetaldehyde impairs lysosomes and releases exosomes to enhance HIV-induced hepatotoxicity. Cytochrome P450 2E1 (CYP2E1)-expressing Huh 7.5 (also known as RLW) cells were exposed to an acetaldehyde-generating system (AGS) for 24 h. We then infected (or not) the cells with HIV-1ADA, then exposed them again to AGS for another 48 h. Lysosome damage was assessed by galectin 3/LAMP1 co-localisation and cathepsin leakage. Additionally, we measured the co-localisation of DRAM 1 and Bax in lysosomes, indicating the contribution of HIV-AGS-triggered lysosomal damage to apoptosis induction in hepatocytes. Expression of lysosome biogenesis–transcription factor, TFEB, was measured by its protein levels and in situ immunofluorescence. Exposure of cells to AGS + HIV caused the greatest amount of lysosome leakage and impaired lysosomal biogenesis, leading to intrinsic apoptosis. Furthermore, AGS exposure impaired the microtubule-dependent translocation of TFEB from the cytosol to the nucleus. This appeared to result from the acetylation of \(\alpha\)-tubulin.

Moreover, ZKSCAN3, a repressor of lysosome gene activation by TFEB, was amplified by AGS. Both these changes contributed to AGS-elicited disruption of lysosome biogenesis and promoted exosome release from hepatocytes. These results demonstrate that acetaldehyde impairs lysosomal integrity and repair, promotes exosome release, and exacerbates HIV-induced hepatotoxicity, offering mechanistic insight into alcohol’s role as a co-factor in liver damage among people with HIV.