Defining molecular pathways triggered by IL-10 and tgfb that drive HIV integration and persistence in TFH cells in lymph nodes - follicular helper T cells (TFH) are believed to be major contributors…

Defining molecular pathways triggered by IL-10 and tgfb that drive HIV integration and persistence in TFH cells in lymph nodes - follicular helper T cells (TFH) are believed to be major contributors to the viral reservoir that persists in HIV-infected individuals, even when on antiretroviral therapy. We will explore the novel hypothesis that cytokines IL-10 and TGF-B, which play important roles in lymph node biology and are upregulated post HIV infection, are critically important for the formation of such a reservoir and represent potential targets for intervention. Specifically, we hypothesize that IL-10/TGF-B promote the differentiation of HIV-susceptible TFH cells, with reduced antiviral defenses, that favor integration of intact proviruses into open chromatin gene targets downstream of IL-10/TGF-B signaling pathways. We will examine multiple aspects of this model, including how IL-10 and TGF-B suppress the intrinsic antiviral machinery in TFH cells and how chromatin accessibility in genes downstream of IL10/TGF-B signaling, promoted by STAT3/smads activation, allows infecting virions to integrate preferentially in these open loci. As a result of these mechanisms, infected TFH cells provide a reservoir of actively transcribing intact proviruses, even under art. In aim 1, we will investigate these hypothesized roles of IL-10 and TGF-B in TFH differentiation and HIV integration/transcription using biobanked samples from lymph nodes of HIV-infected individuals at different stages post HIV infection (i.e. fiebig IV/V, untreated chronic infection, and art-treated). In aim 2, we will mechanistically validate our model, using tools such as crispr gene knockouts in EX vivo tonsil isolated CD4 T cells, to examine how the major pathways identified in aim 1 contribute to the differentiation of TFH cells, the suppression of anti-viral machinery, and the promotion of integration of intact proviruses into active transcription sites. Finally, in aim 3, we will take advantage of lymph node specimens available from a cohort of rhesus macaques that previously controlled SIV replication post-art interruption (VL