Abstract Background Despite the standard antiretroviral therapies, people living with HIV (PLWH) develop chronic lung complications including COPD, fibrosis and bronchiectasis. The underlying mechanism driving these structural and functional alterations remain poorly understood. Previous studies suggest that HIV infection acts as an independent factor promoting chronic pulmonary inflammation. In addition, infiltrating immune cells such as macrophages, T cells, and neutrophils release a variety of mediators that influence the epithelial microenvironment. Based on these observations we hypothesize that sustained inflammation and interaction of the immune compartment with the epithelium serves as key drivers of epithelial to mesenchymal transition (EMT) in lungs of HIV infected subjects. Methods To investigate EMT like alterations during HIV infection, lung tissue samples from age-matched HIV-infected (n = 4) and healthy donors (n = 6) were procured. Inflammatory and EMT related changes were observed by (a) determining the levels of E-cadherin (CDH1), fibronectin (FN1) and vimentin (VIM) using immunoblotting and (b)cytokine profiling using Luminex multiplex assay. We further explored the cellular and molecular landscape of control and HIV infected lung tissues by single cell RNA sequencing (scRNA-seq). Results Western blot analysis revealed a decrease in CDH1 (p-value= 0.0256) and VIM protein (p-value=0.0046) abundance, alongside an increase in FN1(p-value= 0.0696) levels in HIV-infected lung tissues as compared to healthy donors, suggesting an altered EMT like phenotype. Multianalyte analysis comparing healthy (n = 5) and HIV infected lungs (n = 3) showed significant upregulation of multiple inflammatory cytokines including - IFN-γ (p-value= 0.0269), TNF-α (p-value= 0.0344), IL-17 (p-value= 0.0088), and IL-1β (p-value= 0.0208) amongst others, indicating an enhanced pro-inflammatory microenvironment. scRNA-seq analysis showed an increased proportion of immune cells (B cells, T cells and Dendritic cells) and alveolar type II (AT2) cells in HIV-infected samples compared to healthy donors. This cellular shift suggests the emergence of a persistent inflammatory phenotype, we suspect from our results and previous literature that HIV induced immune suppression despite elevated T cell count may promote cellular senescence that could drive premature aging within the diseased lung. Conclusion Our findings suggest that HIV infection induces EMT-like changes in the lung epithelium, driven by a chronic inflammatory and immunosenescent environment. These alterations may contribute to the overall severity of several important lung pathologies observed in the lungs of PLWH, providing new insights into the pathogenesis of HIV-associated pulmonary disease. This abstract is funded by: National Institutes of Health (NIH) R01 HL158316; HL167655; HL147715; R01 R01ES029177 and Tristate SenNet U54 AG075931
Ganaie et al. (Fri,) studied this question.