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Presentation date

8-12-2021

College, Institute, or Department

Internal Medicine

Faculty Mentor

Raghubendra S. Dagur

Research Mentor

Raghubendra S. Dagur

Abstract

Liver fibrosis is the scarring process where excessive extracellular matrix proteins occur and can be caused by exposure to certain toxins or compounds such as alcohol. Alcohol can lead to increased fibrosis and cirrhosis in people living with HIV due to its ability to influence the liver’s microenvironment. Extracellular vesicles (EVs) communicate between cells by transferring their cargo. Under stress, macrophages can communicate with hepatic cells by releasing EVs and potentially progressing liver disease. The current study examines how ethanol affects EVs production from HIV-infected macrophages and how macrophage-derived EVs modulate profibrotic phenotype in hepatic stellate cells. Monocyte-derived macrophages (MDM) were infected with HIV and then exposed to 50 mM EtOH during incubation. The THP-1 monocytes were differentiated to macrophages with PMA (5 ng/mL) before alcohol and HIV treatment. The medium from the macrophages was collected for ultracentrifugation to isolate the EVs. The EVs were quantified using Nanoparticle tracking analysis (NTA). Transcriptional expression of genes was performed with qPCR. LX-2 hepatic stellate cells were exposed to macrophage-derived EVs from different treatment groups to assess profibrotic activation. Ethanol treatment in HIV-infected macrophages increased the production of EVs compared to their respective controls. The majority of the EVs from the MDM cells were in the range of small EVs (50-200 nm). Exposure of EtOH-HIV-induced macrophage EVs to LX2 cells significantly increased the transcriptional expression of profibrotic genes Col1A1, ACTA2, and CTGF. Combined treatment of EtOH and HIV in macrophages downregulated the hsa-miR92a-3p expression in macrophage-derived EVs that binds with its putative target Col1A1 to increase fibrotic changes in recipient LX-2 cells. The findings of this study lead to the conclusion that a combination of ethanol and HIV stimulates macrophage derived EVs with the downregulation of miR92a, which will activate the profibrotic phenotype in hepatic stellate cells. This activation will contribute to the progression of liver disease.

Keywords

Extracellular Vesicles, Macrophages, Hepatic Stellate Cells, Liver Fibrosis

Ethanol-HIV Stimulates Macrophage-derived Extracellular Vesicles to Promote a Profibrotic Phenotype in Hepatic Stellate Cells

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