Stat5-dependent cardioprotection in late remote ischaemia preconditioning

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Ischaemia-Reperfusion Injury

Background:

• Remote ischaemic preconditioning (RIPC) offers protection against myocardial ischaemia/reperfusion (I/R) injury.
• The molecular mechanisms underlying late RIPC-induced cardioprotection remain incompletely understood.
• The role of Signal Transducer and Activator of Transcription 5 (Stat5) in this protective process has not been elucidated.

Purpose of the Study:

• To investigate the protective effects of late RIPC against myocardial I/R injury.
• To determine the involvement of Stat5 in RIPC-mediated cardioprotection.
• To utilize cardiomyocyte-specific Stat5 knockout (Stat5-cKO) mice for this investigation.

Main Methods:

• Mice underwent lower limb RIPC or sham procedure followed by LAD ligation and reperfusion.
• Infarct size, cardiomyocyte apoptosis, and serum cardiac enzymes were assessed.
• Western blotting was used to analyze protein expression of apoptotic markers, survival signaling molecules, HIF-1α, and IL10.

Main Results:

• RIPC significantly reduced infarct size, cardiomyocyte apoptosis, and cardiac enzyme release in wild-type mice.
• Cardioprotective effects of RIPC were abolished in Stat5-cKO mice.
• RIPC increased Stat5 activation, anti-apoptotic proteins (Bcl-xL, Bcl-2), HIF-1α, IL10, and activated PI3K/AKT/VEGF signaling, which were abrogated in Stat5-cKO mice.

Conclusions:

• Late RIPC confers significant cardioprotection against myocardial I/R injury.
• Stat5 is essential for mediating the late protective effects of RIPC.
• RIPC-induced cardioprotection involves the activation of Stat5-dependent anti-apoptotic and pro-survival signaling pathways.