LncRNA-Mhrt regulates cardiac hypertrophy by modulating the miR-145a-5p/KLF4/myocardin axis.

Cardiac hypertrophy is an early milestone of many heart diseases. LncRNAs often play a leading role in this process. However, its mechanism of action in cardiac hypertrophy has not been fully explained. In a previous study, we showed a new mode by which lncRNA-Mhrt inhibited cardiac hypertrophy by inhibiting myocardin. However, the underlying molecular mechanism remains unclear. This study aims to explore potential action modes of Mhrt in regulating the expression of myocardin in the process of cardiac hypertrophy. Here, we find that Mhrt reduces myocardin expression through KLF4 in vivo and in vitro. Meanwhile, Mhrt promotes the expression of KLF4 through direct binding to miR-145a-5p or inhibiting phosphorylation of KLF4 by forming a complex with KLF4 to prevent the binding of ERK and KLF4, thereby inhibiting myocardin expression and the development of myocardial hypertrophy. Taken together, our findings reveal a new pathway, Mhrt-KLF4-myocardin, that regulates cardiac hypertrophy and revealed additional possible action modes of Mhrt in the occurrence and development of cardiac hypertrophy. The new regulatory pathway serves as a potential therapeutic avenue for cardiac hypertrophy.