MicroRNA-129-1-3p protects cardiomyocytes from pirarubicin-induced apoptosis by down-regulating the GRIN2D-mediated Ca(2+) signalling pathway.

Pirarubicin (THP), an anthracycline anticancer drug, is a first-line therapy for various solid tumours and haematologic malignancies. However, THP can cause dose-dependent cumulative cardiac damage, which limits its therapeutic window. The mechanisms underlying THP cardiotoxicity are not fully understood. We previously showed that MiR-129-1-3p, a potential biomarker of cardiovascular disease, was down-regulated in a rat model of THP-induced cardiac injury. In this study, we used Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment analyses to determine the pathways affected by miR-129-1-3p expression. The results linked miR-129-1-3p to the Ca(2+) signalling pathway. TargetScan database screening identified a tentative miR-129-1-3p-binding site at the 3'-UTR of GRIN2D, a subunit of the N-methyl-D-aspartate receptor calcium channel. A luciferase reporter assay confirmed that miR-129-1-3p directly regulates GRIN2D. In H9C2 (rat) and HL-1 (mouse) cardiomyocytes, THP caused oxidative stress, calcium overload and apoptotic cell death. These THP-induced changes were ameliorated by miR-129-1-3p overexpression, but exacerbated by miR-129-1-3p knock-down. In addition, miR-129-1-3p overexpression in cardiomyocytes prevented THP-induced changes in the expression of proteins that are either key components of Ca(2+) signalling or important regulators of intracellular calcium trafficking/balance in cardiomyocytes including GRIN2D, CALM1, CaMK⠡δ, RyR2-pS2814, SERCA2a and NCX1. Together, these bioinformatics and cell-based experiments indicate that miR-129-1-3p protects against THP-induced cardiomyocyte apoptosis by down-regulating the GRIN2D-mediated Ca(2+) pathway. Our results reveal a novel mechanism underlying the pathogenesis of THP-induced cardiotoxicity. The miR-129-1-3p/Ca(2+) signalling pathway could serve as a target for the development of new cardioprotective agents to control THP-induced cardiotoxicity.