Objective: Cardiac hypertrophy is a major cause of heart failure and sudden cardiac death among hypertensive individuals. The present study examined the effects of profilin-1 on hypertension-induced cardiac hypertrophy.
Methods: We used adenovirus injection to knockdown or overexpress profilin-1 in spontaneous hypertensive rats (SHRs). As a control, blank adenovirus was injected into age-matched SHRs and Wistar-Kyoto rats (WKYs). SBP and cardiac mass index were measured. Cardiac tissues were stained with hematoxylin-eosin and sirius red, and cardiac ultrastructure was imaged using transmission electron microscopy. Actin filament was quantified by staining with TRIC-tagged phalloidin. Caveolin-3 abundance and endothelial nitric oxide synthase (eNOS) activity were measured using real-time quantitative PCR, Western blot or immunofluorescence staining.
Results: Endogenous profilin-1 was highly expressed in hypertrophic myocardium of SHRs compared with WKYs. Lowering profilin-1 expression in SHRs significantly attenuated hypertension-induced cardiac hypertrophy and fibrosis and displayed a significant preservation of myofibrils, sarcolemmal caveolae, abundance of caveolin-3 protein, activity of eNOS and production of nitric oxide (NO). In contrast, transgenic overexpression of profilin-1 in SHRs induced more serious cardiac hypertrophy and fibrosis with significant reduction of sarcolemmal caveolae, caveolin-3 protein, eNOS activity, and production of NO when compared with SHR controls.
Conclusion: Profilin-1 promotes cardiac hypertrophy partly through interfering with the formation of sarcolemmal caveolae and attenuating the eNOS/NO pathway. These results demonstrate a crucial role for profilin-1 in hypertensive cardiac hypertrophy.