Qiang-Xin 1 formula improves cardiac function and alleviates myocardial injury in lipopolysaccharide-induced septic mice by activating calcium/calmodulin-dependent protein kinase I-mediated mitophagy.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE: Qiang-Xin 1 (QX1) is a traditional Chinese herbal formula that has been used for decades in treating heart failure. This study is the first to demonstrate its protective effects against sepsis-induced myocardial injury (SIMI). Furthermore, we identified a novel mechanism of QX1 involving calcium/calmodulin-dependent protein kinase I (CaMK I)-mediated mitophagy. AIM OF THE STUDY: This study aimed to investigate whether QX1 alleviates SIMI by modulating CaMK I-mediated mitophagy in lipopolysaccharide (LPS)-induced septic mice and cardiomyocytes. MATERIALS AND METHODS: An LPS-induced septic mouse model and HL-1 cardiomyocytes were treated with QX1 or its medicated serum. Cardiac function was assessed via echocardiography, pathological staining and biochemical measurement. CaMK I's role was validated using siRNA/shRNA knockdown or overexpression. RESULTS: QX1 improved cardiac function, reduced inflammation, and attenuated mitochondrial damage by restoring N-terminal pro-B-type natriuretic peptide, cardiac troponin I, creatine kinase-MB isoenzyme, interleukin-1 beta, tumor necrosis factor alpha and interleukin 6, as well as reversed aberrant levels of Adenosine triphosphate, mitochondrial DNA and membrane potential in SIMI. Mechanistically, QX1 activated mitophagy by upregulating PINK1, Parkin, and LC3-II/I while reducing P62 in the mitochondrial fraction. mRFP-eGFP-LC3 reporter assay and colocalization of LC3 with Parkin in cardiomyocytes demonstrated the enhanced mitophagic flux. Furthermore, in vivo CaMK I knockdown significantly reduced QX1-mediated improvements in cardiac function and mitochondrial integrity. In vitro, autophagy inhibition or CaMK I silencing largely abolished QX1's benefits. CONCLUSION: QX1 protects against SIMI by enhancing CaMK I-dependent mitophagy. These findings highlight QX1's therapeutic potential for sepsis-induced cardiomyopathy. However, these results were obtained from a single standardized batch of QX1, and validation across multiple batches prepared from plants collected under different conditions is necessary to confirm the reproducibility and robustness of these mechanisms.