Polydatin attenuates cardiac hypertrophy through modulation of cardiac Ca²⁺ handling and calcineurin-NFAT signaling pathway

Polydatin (PD), a resveratrol glucoside extracted from the perennial herbage Polygonum cuspidatum, has been suggested to have wide cardioprotective effects. This study aimed to explore the direct antihypertrophic role of PD in cultured neonatal rat ventricular myocytes (NRVMs) and its therapeutic effects against pressure overload (PO)-induced hypertrophic remodeling and heart failure. Furthermore, we investigated the mechanisms underlying the actions of PD. Treatment of NRVMs with phenylephrine for 72 h induced myocyte hypertrophy, where the cell surface area and protein levels of atrial natriuretic peptide and β-myosin heavy chain (β-MHC) were significantly increased. The amplitude of systolic Ca(2+) transient was increased, and sarcoplasmic reticulum Ca(2+) recycling was prolonged. Concomitantly, calcineurin activity was increased and NFAT protein was imported into the nucleus. PD treatment restored Ca(2+) handling and inhibited calcineurin-NFAT signaling, thus attenuating the hypertrophic remodeling in NRVMs. PO-induced cardiac hypertrophy was produced by transverse aortic constriction (TAC) in C57BL/6 mice, where the left ventricular posterior wall thickness and heart-to-body weight ratio were significantly increased. The cardiac function was increased at 5 wk of TAC, but significantly decreased at 13 wk of TAC. The amplitude of Ca(2+) transient and calcineurin activity were increased at 5 wk of TAC. PD treatment largely abolished TAC-induced hypertrophic remodeling by inhibiting the Ca(2+)-calcineurin pathway. Surprisingly, PD did not inhibit myocyte contractility despite that the amplitude of Ca(2+) transient was decreased. The cardiac function remained intact at 13 wk of TAC. In conclusion, PD is beneficial against PO-induced cardiac hypertrophy and heart failure largely through inhibiting the Ca(2+)-calcineurin pathway without compromising cardiac contractility.