HIV AND GP120-INDUCED LOSS OF LIPID DROPLETS IN HEPATIC STELLATECELLS CONTRIBUTES TO A PROFIBROTIC PROFILE

ALICIA LOPEZ; NICOLE FREIBERGER; ALEX GUANO; CINTIA CEVALLOS; FRANCO SVIERCZ; PATRICIO JARMOLUK; JORGE QUARLERI; M. VICTORIA DELPINO

Congreso; LXXI REUNIÓN CIENTÍFICA ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI) 9 -11 de noviembre de 2023 Universidad Nacional de San Luis-San Luis; 2023

Liver fibrosis involves the excessive accumulation of extracellular matrix proteins in response to chronic diseases. HIV infection accelerates the rate of liver fibrosisprogression in patients co-infected with HCV or HBV, compared to those who are only mono-infected. The earliest event in the progression of liver fibrosis is the activation of hepatic stellate cells (HSC), which leads to an increase in the synthesis of extracellular matrix proteins. Quiescent HSC store vitamin A within perinuclear droplets. The initial stage of HSC activation involves the depletion of these lipid droplets, followed by an increase in α-smooth muscle actin (SMA) and the secretion of collagen in a mechanism that involves TGF-β and IL-6. CCR5 was implicated in the activation of hepatic stellate cells. Given that HIV-R5 tropic strains bind to CCR5 via their gp120 glycoprotein, the goal of this study was to assess the impact of HIV and its gp120 glycoprotein on HSC activation using the LX-2 cell line. CCR5 and CXCR4, in conjunction with CD4, play a crucial role in the adsorption and entry of HIV into cells. We found that 15.1 ± 0.85% of LX-2 cells expressed the CCR5 receptor, while 27.65 ± 0.82% of cells expressed CD4. Negligible levels of CXCR4 were detected.Experiments were conducted to determine whether HIV-R5 and gp120 induce loss of lipid droplets, the expression of IL-6, α-SMA, TGF-β, and cellular proliferation. To this end, LX-2 cells were infected with HIV-R5 (AD8 strain, MOI 0.5 pg (p24)) or stimulated with gp120 (500 ng/ml). HIV infection induced the loss of lipid droplets (Microscopy, Bodipy 493/503). The gp120 from HIV-R5 mimicked the changes associated with lipid droplets loss induced by the infection. This effect was reversed when experiments were performed in the presence of the CCR5 antagonist TAK-779. This process involved an increase in PPAR-α (**p < 0.01) and an augmentation of lysosomal acid lipase (LAL) expression (**p < 0.01) (RT-qPCR).In concordance, HIV infection and gp120 induced an increase in the colocalization of lipid droplets with lysosomes (Microscopy, ****p < 0.0001) strongly suggesting that lipophagy could play a role in this process. HIV infection induced IL-6 secretion (ELISA), but was unable to induce the expression of TGFβ (RT-qPCR) and α-smooth muscle actin (α-SMA) (RT-qPCR and immunofluorescence); as well as collagen deposition (Microscopy, Sirius red staining and immunofluorescence). IL-6 could promote HSC survival and proliferation, which correlates with the extent of fibrosis. However, HIV infection was unable to induce cell proliferation (violet proliferation dye, cytometry).The present study provides evidence that HSC exposed to HIV R5 or the gp120glycoprotein induce the loss of lipid droplets, a critical step in initiating HSC activation. This sets in motion a series of interactions that may contribute to accelerating the progression of hepatic fibrosis observed in coinfected individuals.