Azelnidipine protects HL-1 cardiomyocytes from hypoxia/reoxygenation injury by enhancement of NO production...

Area of Science:

• Cardiology
• Cell Biology
• Pharmacology

Background:

• Pharmacological preconditioning by calcium (Ca²⁺) antagonists in protecting the heart against ischemia/reperfusion (I/R) injury requires elucidation.
• Investigating the protective mechanisms of azelnidipine against hypoxia/reoxygenation (H/R) injury in cardiomyocytes is crucial.

Purpose of the Study:

• To determine if and how azelnidipine pretreatment protects cardiomyocytes against H/R injury.
• To investigate the role of nitric oxide (NO) synthase (NOS), NO production, cell death, apoptosis, and action potential durations (APDs) in azelnidipine's protective effects.

Main Methods:

• HL-1 cardiomyocytes were used to study the effects of azelnidipine on NOS expression, NO production, cell death, and apoptosis during H/R.
• Whole-cell patch-clamp technique was employed to measure APDs.
• Inhibitors of NOS (L-NAME), heat shock protein 90 (geldanamycin), and antioxidants (N-acetylcysteine) were used to probe mechanisms.
• RNA sequencing (RNA-seq) was performed to analyze gene expression changes.

Main Results:

• Azelnidipine enhanced endothelial NOS phosphorylation and NO production in normoxic HL-1 cells, effects abolished by geldanamycin and N-acetylcysteine.
• Pretreatment with azelnidipine reduced H/R-induced cell death and shortened APDs.
• These protective effects were diminished by L-NAME but unaffected by T-type and N-type Ca²⁺ channel inhibitors.
• Azelnidipine's protective effects on cell death were independent of additional treatment during H/R or altered extracellular Ca²⁺ concentrations.
• RNA-seq data revealed that azelnidipine-attenuated cell death, dependent on NO production, did not involve significant changes in the NO/cGMP/PKG pathway gene expression.

Conclusions:

• Pretreatment with azelnidipine protects HL-1 cardiomyocytes against H/R injury.
• The protection mechanism involves NO-dependent action potential duration shortening and L-type Ca²⁺ channel blockade.
• These effects occur independently of significant alterations in gene expression related to the NO/cGMP/PKG pathway.