Mitochondrial Calcium Exchange links Metabolism with the Epigenome to Control Cellular Differentiation (ATAC-seq)

Fibroblast to myofibroblast differentiation is crucial for the initial healing response but excessive myofibroblast activation leads to pathological fibrosis. Therefore, it is imperative to understand the mechanisms underlying myofibroblast formation. Here we report that mitochondrial calcium (mCa2+) signaling is a regulatory mechanism in myofibroblast differentiation and fibrosis. We demonstrate that inhibition of mCa2+ uptake in fibroblasts enhances myofibroblast formation and this translates to increased fibrosis following injury. Fibrotic signaling alters the gating of the mitochondrial calcium uniporter (mtCU) to reduce mCa2+ uptake and induce specific changes in metabolism. mCa2+-dependent metabolic reprogramming leads to the activation of αKG-dependent demethylases which epigenetically modify promoter regions specific to the myofibroblast gene program resulting in differentiation. Our results uncover an important role for mCa2+ uptake beyond metabolic regulation and cell death and demonstrate that mCa2+ signaling regulates the epigenome to influence cellular differentiation. Examination of changes in chromatin accessibliity associated with myofibroblast differentiation