MicroRNA-377 Mediates Cardiomyocyte Apoptosis Induced by Cyclosporin A

Area of Science:

• Cardiology
• Molecular Biology
• Pharmacology

Background:

• Cyclosporin A (CsA) is a vital immunosuppressant with broad clinical use.
• CsA's therapeutic applications are hindered by its cardiotoxicity, hepatotoxicity, and nephrotoxicity.
• The precise mechanisms underlying CsA-induced cardiotoxicity remain incompletely understood.

Purpose of the Study:

• To elucidate the molecular mechanisms by which CsA induces apoptosis in cardiomyocytes.
• To investigate the role of microRNA-377 (miR-377) in CsA-mediated cardiotoxicity.

Main Methods:

• Microarray analysis to identify CsA-regulated microRNAs.
• In vitro studies involving ectopic miR-377 overexpression and inhibition in cardiomyocytes.
• Assessment of apoptosis markers, including cell counts, protein levels (pro- and anti-apoptotic), and caspase activity.
• Identification and validation of miR-377 direct targets using in vitro and in vivo models.

Main Results:

• CsA treatment significantly altered microRNA expression, notably upregulating miR-377.
• Overexpression of miR-377 promoted cardiomyocyte apoptosis, increasing apoptotic cells and caspase activity while decreasing anti-apoptotic proteins.
• Inhibition of miR-377 attenuated CsA-induced cardiomyocyte apoptosis.
• XIAP and NRP2 were identified as direct targets of miR-377, with their expression downregulated by both miR-377 and CsA.

Conclusions:

• CsA induces cardiomyocyte apoptosis via a mechanism involving the upregulation of miR-377.
• The miR-377 targets the anti-apoptotic proteins XIAP and NRP2, contributing to CsA cardiotoxicity.
• The miR-377-XIAP/NRP2 axis represents a potential therapeutic target for mitigating CsA-induced cardiotoxicity.