A20 upregulation during treated HIV disease is associated with intestinal epithelial cell recovery and function

Abstract

Untreated Human Immunodeficiency Virus (HIV) infection is characterized by intestinal epithelial barrier dysfunction and chronic inflammation, related features that are attenuated to variable degrees by suppressive antiretroviral therapy (ART). Specific mediators of intestinal epithelial cell (IEC) dysfunction and restoration during HIV disease and treatment have yet to be identified. We studied IECs isolated from intestinal biopsies by RNAseq and found that mRNA levels for the ubiquitin-modifying enzyme, A20, are upregulated in ART-treated individuals and are positively correlated with markers of epithelial function (e.g., CTNNB, CLDN4, and TJP1). In a murine intestinal organoid model, A20 expression was suppressed by interferon-alpha (IFNα), which is highly expressed during HIV viremia and induces IFN-mediated signaling. Notably, A20 deletion rendered intestinal organoids more susceptible to cell death and inhibition of barrier-related genes mediated by interferon-gamma (IFNγ), a cytokine also present at elevated levels during untreated infection. Furthermore, A20 specifically restricted expression of IL-17A-induced inflammatory genes in organoids. Finally, ART-suppressed chronically infected individuals treated with pegylated IFNα2a for five weeks demonstrated reduced expression of A20 in peripheral blood mononuclear cells. Our results are thus consistent with a model in which enhanced type I interferons suppress A20 levels, leading to IFNγ-mediated dysfunction. As such, variation in A20 expression during the course of HIV infection could underlie both the development of epithelial dysfunction before the initiation of ART and the recovery of intestinal epithelial integrity thereafter.