Galectin-3-centered paracrine network mediates cardiac inflammation and fibrosis upon β-adrenergic insult

Rapid over-activation of β-adrenergic receptors (β-AR) following acute stress initiates cardiac inflammation and injury by activating interleukin-18 (IL-18),however,the process of inflammation cascades has not been fully illustrated.The present study aimed to determine the mechanisms of cardiac inflammatory amplification following acute sympathetic activation.With bioinformatics analysis,galectin-3 was identified as a potential key downstream effector of β-AR and IL-18 activation.The serum level of galectin-3 was positively correlated with norepinephrine or IL-18 in patients with chest pain.In the heart of mice treated with β-AR agonist isoproterenol (ISO,5 mg kg^(-1)),galectin-3 expression was upregulated markedly later than IL-18 activation,and Nlrp3^(-/-)and Il18^(-/-)mice did not show ISO-induced galectin-3 upregulation.It was further revealed that cardiomyocyte-derived IL-18 induced galectin-3 expression in macrophages following ISO treatment.Moreover,galectin-3deficiency suppressed ISO-induced cardiac inflammation and fibrosis without blocking ISO-induced IL-18 increase.Treatment with a galectin-3 inhibitor,but not a β-blocker,one day after ISO treatment effectively attenuated cardiac inflammation and injury.In conclusion,galectin-3 is upregulated to exaggerate cardiac inflammation and injury following acute β-AR activation,a galectin-3 inhibitor effectively blocks cardiac injury one day after β-AR insult.