TGFB1 and heart failure: In heart failure, circRNA Slc8a1 sponges and inhibits miR-133a, disallowing its antifibrotic actions on TGFβ signaling, specifically the regulation of serum response factor (SRF) and connective tissue growth factor (CTGF) expression as well as components of the β1-adrenergic receptor transduction cascade [76•].