PCSK6 was secreted into the extracellular space and activated TGF-β, which initiated Smad signaling and ultimately exacerbated cardiac fibrosis.236 In addition, in a dilated cardiomyopathy (DCM) mouse model generated by cardiac-specific knockdown of lamin A/C, Yin Yang 1 (YY1) increased the expression of bone morphogenetic protein 7 (BMP7) but suppressed connective tissue growth factor (CTGF) expression in cardiomyocytes, which suppressed TGFβ/Smad signaling in the heart and inhibited fibrosis.237. This evidence concerns the gene YY1 and familial dilated cardiomyopathy.