Involvement of microRNA-23b-5p in the promotion of cardiac hypertrophy and dysfunction via the HMGB2 signaling pathway.

The processes involved in the progression of myocardial cells towards hypertrophy and its gradual transition to heart failure represent a multifactorial health disorder. The aim of this study was to identify the molecular mechanism(s) underlying the abnormal overexpression of miR-23b-5p and its involvement in the promotion of cardiac hypertrophy and dysfunction via HMGB2. A type 9 recombinant adeno-associated virus (rAAV9) was employed to manipulate miR-23b-5p expression under conditions of thoracic aortic constriction (TAC)-/angiotensin-II (Ang-II)-induced cardiac dysfunction. Cardiac structures and functions were assessed by echocardiography and invasive pressure-volume analysis. HMGB2 expression under conditions of cardiac hypertrophy was detected by western blotting. The biochemical relationship between miR-23b-5p and HMGB2 was verified using a luciferase reporter vector, lentiviral construct comprising the miR-23b-5p mimic sequence, and microRNA inhibitor (miR-inhibitor). The expression levels of miR-23b-5p were increased in the hearts under conditions of both Ang-II- and TAC-induced cardiac hypertrophy. The results of the luciferase activity analysis showed that HMGB2 is a supposed target of miR-23b-5p. miR-23b-5p overexpression in vivo aggravated pressure overload-induced cardiac hypertrophy and dysfunction, whereas the miR-inhibitor increased HMGB2 expression and reversed these effects. In the present study, we observed that miR-23b-5p mediates and is involved in the aggravation of cardiac hypertrophy and dysfunction via the HMGB2 signaling pathway.