Chlorogenic acid attenuates cardiac hypertrophy via up‐regulating Sphingosine‐1‐phosphate receptor1 to inhibit endoplasmic reticulum stress

Abstract Aims Cardiac hypertrophy, an adaptive response of the heart to stress overload, is closely associated with heart failure and sudden cardiac death. This study aimed to investigate the therapeutic effects of chlorogenic acid (CGA) on cardiac hypertrophy and elucidate the underlying mechanisms. Methods and results To simulate cardiac hypertrophy, myocardial cells were exposed to isoproterenol (ISO, 10 μM). A rat model of ISO‐induced cardiac hypertrophy was also established. The expression levels of cardiac hypertrophy markers, endoplasmic reticulum stress (ERS) markers, and apoptosis markers were measured using quantitative reverse transcription PCR and western blotting. The apoptosis level, size of myocardial cells, and heart tissue pathological changes were determined by terminal deoxynucleotidyl transferase dUTP nick‐end labelling staining, immunofluorescence staining, haematoxylin and eosin staining, and Masson's staining. We found that CGA treatment decreased the size of ISO‐treated H9c2 cells. Moreover, CGA inhibited ISO‐induced up‐regulation of cardiac hypertrophy markers (atrial natriuretic peptide, brain natriuretic peptide, and β‐myosin heavy chain), ERS markers (C/EBP homologous protein, glucose regulatory protein 78, and protein kinase R‐like endoplasmic reticulum kinase), and apoptosis markers (bax and cleaved caspase‐12/9/3) but increased the expression of anti‐apoptosis marker bcl‐2 in a dose‐dependent way (0, 10, 50, and 100 μM). Knockdown of sphingosine‐1‐phosphate receptor 1 (S1pr1) reversed the protective effect of CGA on cardiac hypertrophy, ERS, and apoptosis in vitro (P