Fast skeletal myosin binding protein-C expression exacerbates dysfunction in heart failure
摘要
During heart failure (HF), gene and protein expression profiles undergo extensive compensatory and pathological remodeling. We previously observed that fast skeletal myosin binding protein-C (fMyBP-C) is upregulated in diseased mouse hearts. While fMyBP-C shares significant homology with its cardiac paralog, cardiac myosin binding protein-C (cMyBP-C), there are key differences that may affect cardiac function. However, the consequence of cardiac expression of fMyBP-C is unknown. Here, we aim to elucidate the impact of fMyBP-C expression on cardiac function and pathology. To determine the sufficiency of fMyBP-C to cause cardiac dysfunction, we generated cardiac-specific fMyBP-C over-expression mice. These mice were crossed into cMyBP-C null mice to assess the effect of fMyBP-C in the complete absence of cMyBP-C. Finally, fMyBP-C null mice underwent transverse aortic constriction (TAC) to define the requirement of fMyBP-C in HF. We confirmed the upregulation of fMyBP-C in several models of cardiac disease, including lineage tracing models. Low levels of fMyBP-C caused mild cardiac remodeling and sarcomere dysfunction. Exclusive expression of fMyBP-C in a HF model exacerbated cardiac pathology. Furthermore, reduction of fMyBP-C expression by shRNA in HF improved cardiac function. Following pressure overload, fMyBP-C null mice demonstrated greater resistance to cardiac decompensation. Mechanistically, our data suggest the differential regulation of the myosin super-relaxed state by cMyBP-C and fMyBP-C plays a contributing role. These findings suggest the elevated expression of fMyBP-C in diseased hearts is a pathological response. Targeted therapies to prevent upregulation of fMyBP-C may prove beneficial in the treatment of HF.