Calpain-2 as a therapeutic target for sodium danshensu in mitigating myocardial ischaemia-reperfusion injury.

BACKGROUND AND PURPOSE: Myocardial reperfusion, a life-saving intervention after heart attacks, paradoxically induces myocardial ischaemia-reperfusion injury (MIRI), a detrimental condition. MIRI is a persistent clinical challenge stemming from an incomplete understanding of its pathogenic mechanisms. This study aimed to identify the direct molecular target of sodium danshensu (SDSS) and elucidate the underlying mechanism by which it attenuates MIRI. EXPERIMENTAL APPROACH: We integrated in vivo (left anterior descending artery ligation and reperfusion model) and in vitro (hypoxia-reoxygenation model) approaches with proteomic profiling (HuProt™ microarray and liquid chromatography-tandem mass spectrometry [LC-MS/MS]), biophysical validation (cellular thermal shift assay [CETSA] and drug affinity responsive target stability [DARTS]) and molecular docking. The functional role of the identified target, calpain-2 (CAPN2) was further confirmed through pharmacological inhibition and genetic overexpression experiments. KEY RESULTS: SDSS administration significantly attenuated MIRI in in vivo and in vitro models. Using direct target-related technologies, CAPN2 was identified as a direct binding target of SDSS and was shown to be highly expressed in the heart. According to pathway enrichment analysis, CAPN2-mediated apoptosis in cardiomyocytes was a primary mechanism by which SDSS alleviated MIRI. The cardioprotective effects of SDSS were replicated by a selective CAPN2 inhibitor and abolished upon CAPN2 overexpression. CONCLUSIONS AND IMPLICATIONS: SDSS confers cardioprotection by directly targeting and inhibiting CAPN2. This establishes CAPN2 as a potential therapeutic target for MIRI and provides a mechanistic basis for the development of SDSS-based therapies.