Catestatin: A master regulator of cardiovascular functions

Background: Cardiovascular disease (CVD), the most common cause of death globally, accounts for ~30% of all deaths worldwide. Hypertension is a common contributor to morbidity and mortality from CVD. Methods and Results: The plasma concentration of chromogranin A (CgA) is elevated in patients with CVD as well as patients with established human essential hypertension and heart failure (HF). In contrast, the plasma level of the CgA-derived peptide catestatin (CST) is diminished in human essential hypertension. Low conversion of CgA-to-CST has been associated with increased mortality in patients hospitalized with acute HF. Consistent with human findings, the lack of CST in CgA knockout (Chga-KO) mice eventuates in the development of hypertension and supplementation of CST to Chga-KO mice restores blood pressure, implicating CST as a key player in regulating hypertension. In the peripheral system, CST decreases blood pressure by stimulating histamine release, inhibiting catecholamine secretion, or causing vasodilation. Centrally, CST improves baroreflex sensitivity (BRS) and heart rate variability (HRV) by exciting GABAergic neurons in the caudal ventrolateral medulla (CVLM) and pyramidal neurons of the central amygdala; CST also decreases BRS by exciting glutamatergic rostral ventrolateral medulla (RVLM) neurons. In addition, CST provides cardioprotection by inhibiting inotropy and lusitropy; activating mitochondrial KATP channels, and stimulating reperfusion injury salvage kinase (RISK) and survivor activating factor enhancement (SAFE) pathways and consequent inhibition of mitochondrial permeability transition pore (mPTP). CST modulates cardiomyocyte Ca2+ levels by direct inhibition of Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) activity and consequent reduction in phosphorylation of phospholamban and ryanodine receptor 2, thereby providing support for a direct functional role of CST in the failing myocardium. Conclusion: These multitude of effects establish CST as a master regulator of cardiovascular functions.