TET3 is a regulator and can be targeted for the intervention of myocardial fibrosis.

Cardiac fibrosis contributes to adverse cardiac remodeling and loss of heart function eventually leading to heart failure (HF). Resident cardiac fibroblasts are the principal source of myofibroblasts that produce extracellular matrix proteins to mediate cardiac fibrosis. We report that TET3 depletion in cultured cardiac fibroblasts blocked transition to myofibroblasts in response to different pro-fibrogenic stimuli. Consistently, deletion of TET3 from quiescent or activated fibroblast (myofibroblast) attenuated cardiac fibrosis and rescued heart function in mice. Importantly, a small-molecule TET3-specific degrader Bobcat339 displayed therapeutic potential by mitigating cardiac fibrosis and normalizing heart function when administered post-surgery. Integrated transcriptomic analysis identified the mechanosensor Piezo2 as a downstream target for TET3. Piezo2 inhibition dampened fibroblast activation in vitro and ameliorated cardiac fibrosis in vivo. Mechanistically, Piezo2 promoted fibroblast activation by modulating the activities of mechanosensitive transcription factors. Finally, relevance of TET3 and Piezo2 was verified in heart specimens collected from HF patients. In conclusion, our data demonstrate that TET3 is a pivotal regulator of cardiac fibrosis and can be potentially targeted for the intervention of heart failure.