GSE124264
miRNA142-3p targets Tet2 and impairs Treg differentiation and stability in models of type 1 diabetes
In type 1 diabetes (T1D), the appearance of multiple islet autoantibodies indicates the onset of islet autoimmunity, often many years before clinical symptoms arise. However, the underlying molecular mechanisms in T cells that can promote aberrant activation thereby triggering autoimmune progression remain poorly understood. Here, we show that during early stages of islet autoimmunity a miRNA142-3p/Tet2 signaling axis in murine and human CD4+T cells interferes with the efficient induction of regulatory T (Treg) cells accompanied by impairments in Treg stability. Specifically, we demonstrate that miR142-3p is induced in islet autoimmunity, while its inhibition enhances Treg induction and stability accompanied by a reduction of islet autoimmunity in non-obese diabetic (NOD) mice. Mechanistically, using HITS-CLIP analyses we identify the methylcytosine dioxygenase Tet2 as a direct target of miR142-3p in CD4+T cells, thereby linking high miR142-3p levels to epigenetic remodeling and impairments in Treg induction and stability. These findings offer a new mechanistic model where during islet-autoimmunity miR142-3p/Tet2-mediated Treg instability can contribute to autoimmune activation and progression. Overall design: We performed HITS-CLIP analysis of microRNAs and mRNA fragments present in the RNA-induced silencing complex (RISC) of human CD4+ T cells.