PECAM-1 preserves cardiac function in pressure overload-induced biomechanical stress

Background: Haemodynamic forces play a critical role in proper development of the heart, however much less is known about the mechanisms that regulate cardiac remodelling and function in response to haemodynamic stress in the adult. Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a cell adhesion and signalling molecule that has important roles in regulation of junctional integrity, transendothelial migration and mechanotransduction in response to fluid shear stress. Our previous work identified a role for PECAM-1 in regulating baseline cardiac function via regulation of endothelial-cardiomyocyte communication. Methods: This study investigates the role of PECAM-1 in cardiac remodelling in response to biomechanical stress due to pressure overload induced by transaortic constriction (TAC). Results: Our data reveal that loss of PECAM-1 is associated with systolic dysfunction that is further accentuated following TAC. Adaptive increases in cardiomyocyte cross-sectional area, capillary density and hypertrophic gene expression were all affected with loss of PECAM-1. In control mice, maintained cardiac function was associated with activation of the c-Jun NH(2)-terminal kinase (JNK) pathway, whereas PECAM-1 deletion significantly decreased JNK activation after pressure overload. Our data suggest that in the absence of PECAM-1 signalling, inadequate remodelling of the heart under increased mechanical strain leads to further deterioration of cardiac function, characterized by reduced cardiomyocyte hypertrophy, capillary density and defects in the JNK signalling pathway. Conclusions: Our study reveals a role for PECAM-1 in preservation of cardiac function in response to biomechanical stress induced by pressure overload.