IL-17A Promotes HIV-1 Dissemination/Replication and abrogates the Interferon-Mediated Antiviral Immunity in Intestinal Epithelial Cells

The crosstalk between intestinal epithelial cells (IEC) and Th17-polarized CD4+ T-cells is critical for mucosal homeostasis, with HIV-1 causing major alterations in people living with HIV (PLWH) despite antiretroviral therapy (ART). Here, we used a model of IEC:T-cell co-culture to investigate the effects of IL-17A and TNF, two cytokines produced by Th17-cells, in regulating IEC ability to promote de novo infection and viral outgrowth from reservoir cells. Our results demonstrated that IL-17A in the presence/absence of TNF acts on IEC to increase HIV capture and trans infection of CD3/CD28-activated T-cells from uninfected individuals. Also, IL-17A-exposed IEC significantly increased HIV replication and outgrowth in CD3/CD28-activated T-cells infected with HIV in vitro and isolated from ART-treated PLWH, respectively. Exposure of IEC to IL-17A resulted in decreased type I IFN levels, as measured using the 293T-KEK cell based assay. Illumina RNA sequencing performed on cytokine-activated IEC before/after co-culture with T-cells of ART-treated PLWH revealed a molecular signature associated with IL-17A-mediated proviral effects. This signature includes decreased expression of transcripts linked to type I IFN production/response (DDX60, IRF7, STAT1) and HIV restriction (IFITM1, TRIM5, IF2AK2, MX1, MX2, IFIT1,3,5, PARP12, HERC6, ISG15, viperin, BST2, OAS2/3), and increased expression of Th17-attracting chemokines (CCL20). Overall design: 3 patients + IEC cell line , 4 conditions: Medium. TNF, IL17, TNF + IL17