Epigenetic dysregulation plays an important role in the pathogenesis of lupus. We recently described a pro-inflammatory epigenetic reprogramming of nave CD4+ T cells upon increased disease activity in lupus patients. Our data suggest that the epigenetic regulator EZH2 might be mediating these epigenetic changes. Indeed, we show that EZH2 is increased in CD4+ T cells from lupus patients, and that both miR-26a and miR-101 which regulate EZH2 are downregulated. Both microRNAs have been shown to be sensitive to glucose concentrations, and we show that inhibiting glycolysis restores the expression of these two microRNAs in lupus CD4+ T cells. We hypothesize that increased glycolysis in lupus CD4+ T cells, results in upregulation of EZH2 via downregulating miR-26a and miR-101. Further, we provide evidence that EZH2 overexpression in lupus CD4+ T cells upregulates JAM-A which mediates increased T cell adhesion. We propose to determine a mechanistic explanation of EZH2 overexpression in lupus CD4+ T cells and how this might be linked to increased glycolysis and mTORC1 signaling. We will also identify the complete repertoire of genes and pathways dysregulated by EZH2 overexpression in lupus CD4+ T cells to identify novel therapeutic targets. In addition, given our data suggesting abrogation of increased CD4+ T cells adhesion in lupus patients following EZH2 inhibition in vitro, and that EZH2 inhibition in vivo significantly improves survival and ameliorates lupus-like disease in MRL/lpr lupus-prone mice, we propose to use genetic approaches to characterize the effects of targeted CD4+ T cell Ezh2 deletion in a murine model of lupus. EZH2 inhibitors are currently being trialed for a number of malignancies, and therefore, our results will pave the way for targeting EZH2, or EZH2-regulated genes we will identify, in lupus patients.
Lupus is a chronic systemic autoimmune disease that causes significant morbidity and mortality. We recently showed that EZH2 mediates a pro-inflammatory epigenetic shift in lupus CD4+ T cells upon increased disease activity. Our studies will uncover mechanisms of EZH2 overexpression and the relationship between EZH2 expression and glycolysis in lupus CD4+ T cells, characterize the repertoire of genes and pathways dysregulated by EZH2 overexpression, and determine if CD4+ T cell-specific targeting of EZH2 or EZH2- regulated genes has potential therapeutic benefit in lupus.
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