Introduction: The phospholamban (PLN) cardiomyopathy is a highly prevalent cause of inherited cardiomyopathies in Dutch populations, caused by a single arginine deletion in the phospholamban gene (PLNR14del), which presents with an early-onset of heart failure and spontaneous lethal ventricular arrhythmias leading to sudden cardiac death. Currently, there is still no effective treatment to prevent or treat the progression of the disease. Therefore, we hypothesize that sodiumglucose cotransporter 2 inhibitors (SGLT2i) such as empagliflozin, which has been recently shown to improve cardiovascular outcomes in patients with heart failure, could rescue contractile dysfunction and decrease the arrhythmogenic risk in PLN cardiomyopathy by direct modulation of calcium/calmodulin dependent kinase II (CaMKII) overactivity.
Explanation of basic methods: We modelled hallmarks of PLN cardiomyopathy, such as impaired contractility and increased calcium transient duration in an in vitro model using human pluripotent stem cell-induced cardiomyocytes (hiPSC-CMs) derived from patients with PLN cardiomyopathy (R14del-hiPSC-CMs) and compared them to their healthy isogenic control (WT-hiPSC-CMs). We treated R14del-hiPSC-CMs and WT-hiPSC-CMs with empagliflozin for 4 days and evaluated the contractile function and calcium transient time using functional cellular imaging assays. In addition, we studied the effect of empagliflozin treatment on CaMKII phosphorylation by determining protein expression in R14del-hiPSC-CMs and WT-hiPSC-CMs through western blot.
Results: We observed significant restoration of contractile dysfunction and a decrease of elevated calcium transient time in R14del-hiPSCCMs treated with empagliflozin when compared with WT-hiPSC-CMs. In addition, we identified that non-treated R14del-hiPSC-CMs presented increased levels of CaMKII phosphorylation at baseline with respect to WT-hiPSC-CMs, which significantly decreased after treatment with empagliflozin.
Conclusions/implications: In this study, we have shown that empagliflozin therapy successfully rescued the contractile dysfunction seen in R14del-hiPSC-CM, as well as decreased the elevated calcium transient time by mechanisms involving inhibition of CaMKII phosphorylation. In conclusion, our study contributes valuable insights for repurposing SGLT2i as a new therapeutic strategy to ameliorate contractile dysfunction and decrease arrhythmogenic risk in patients with PLN cardiomyopathy. ❑
