SerpinB1 targeting safeguards against pathological cardiac hypertrophy and remodelling by suppressing cardiomyocyte pyroptosis and inflammation initiation.

Aims: While the pivotal role of inflammation in pathological cardiac hypertrophy and remodelling is widely acknowledged, the mechanisms triggering inflammation initiation remain largely obscure. This study aims to elucidate the role and mechanism of serpin family B member 1 (SerpinB1) in pro-inflammatory cardiomyocyte pyroptosis, heart inflammation, and cardiac remodelling.

Methods And Results: C57BL/6J wild-type, inducible cardiac-specific SerpinB1 overexpression or knockout mice underwent transverse aortic constriction (TAC) surgery. Cardiac hypertrophy and remodelling were assessed through echocardiography and histology. Cardiomyocyte pyroptosis and heart inflammation were monitored. Adeno-associated virus 9 -mediated gene manipulations and molecular assays were employed to explore the mechanisms through which SerpinB1 regulates cardiomyocyte pyroptosis and heart inflammation. Finally, recombinant mouse SerpinB1 protein (rSerpinB1) was administrated both in vivo through osmotic minipump delivery and in vitro to investigate the therapeutic potential of SerpinB1 in cardiac remodelling. Myocardial SerpinB1 overexpression was up-regulated shortly upon TAC or phenylephrine challenge, with no further elevation during prolonged hypertrophic stimuli. It is important to note that cardiac-specific overexpression of SerpinB1 markedly attenuated TAC-induced cardiac remodelling, while deletion of SerpinB1 exacerbated it. At the mechanistic level, SerpinB1 gain-of-function inhibited cardiomyocyte pyroptosis and inflammation in hypertrophic hearts; the protective effect was nullified by overexpression of either cleaved N-terminal gasdermin D or cleaved caspase-1. Co-immunoprecipitation and confocal assays confirmed that SerpinB1 directly interacts with caspase-1 in cardiomyocytes. Remarkably, rSerpinB1 replicated the cardioprotective effect against cardiac hypertrophy and remodelling.

Conclusion: SerpinB1 safeguards against pathological cardiac hypertrophy and remodelling by impeding cardiomyocyte pyroptosis to suppress inflammation initiation, achieved through interaction with caspase-1 to inhibit its activation. Targeting SerpinB1 could represent a novel therapeutic strategy for treating pathological cardiac hypertrophy and remodelling.