Introduction/Rationale: TH17 cells are a subset of CD4+ T cells that mediate autoimmune and chronic inflammatory pathology. Our lab has previously demonstrated that REV-ERB𝛼, a member of the nuclear receptor superfamily of ligand-regulated transcription factors, represses TH17 development in vitro and protects against relevant models of disease in vivo. While REV-ERBα’s target genes and binding sites have been identified across multiple tissues, little is known about the transcriptional machinery that drives its function.
Methods: We coupled MiniTurboID proximity labeling with label-free proteomics to 1) identify key proteins that facilitate REV-ERB𝛼-mediated gene repression in primary, murine TH17 cells and 2) further understand how ligands modulate this process. Furthermore, we have conducted a pooled in vivo RNAi screen to examine our proteomics hits in a physiologically relevant context. Specifically, we utilized Il17a reporter REV-ERB deficient and sufficient T-cells along with shRNAs targeting our identified REV-ERBα interactors in a mouse model of colitis.
Results: Comparison of the REV-ERB𝛼 interactome induced by the presence and absence of endogenous ligand binding reveals potential canonical and non-canonical mechanisms of repression. Additionally, comparison of the shRNAs enriched in colon cells expressing high versus low levels of IL-17A have elucidated which REV-ERB𝛼 interactors regulate TH17 pathogenicity in a REV-ERB-dependent manner.
Conclusion: Ultimately, these efforts aim to bolster our understanding of the REV-ERBs, nuclear receptor biology, and TH17 pathogenesis—all of which may inform the development of focused therapeutics for treatment of autoimmune and chronic inflammatory diseases.
