Jingfang Granule mitigates Coxsackievirus B3-induced myocardial damage by modulating mucolipin 1 expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Jingfang Granules (JFG) originate from the traditional herbal formula Jingfang Baidu powder. It has the effects of inducing sweating and dispelling wind. It is a classic medication used for treating external pathogenic factors and viral diseases. However, the therapeutic mechanism of JFG for viral myocarditis needs further clarification.

AIM OF THE STUDY: This study aimed to explore the therapeutic efficacy of JFG on coxsackievirus B3-induced viral myocarditis (VMC), along with the elucidation of its underlying mechanisms.

MATERIALS AND METHODS: C57 BL/6JNifdc mice were divided randomly into several groups: control, model, Jingfang Granule groups (0.23, 0.46, and 0.69 g/20g, respectively), and a positive group (oseltamivir, 19.33 mg/kg). Following the establishment of the VMC model, the mice underwent an 8 -week treatment regimen. Pathological alterations in cardiac tissues and inflammatory protein expression were monitored. Differential gene analysis was conducted utilizing transcriptomic techniques. The differential gene mucolipin 1 (Mcoln1) was knocked down by transfection with siRNA in H9C2 cell, and investigative techniques such as immunoblotting, qRT-PCR, immunofluorescence, JC-1 staining, reactive oxygen species (ROS) detection, and mitochondrial stress testing were employed to examine its mechanism of action.

RESULTS: JFG significantly mitigates the pathological damage observed in the cardiac tissues of CVB3-induced VMC mice and attenuates the expression of inflammatory genes. Subsequently, differentially expressed genes are identified through transcriptomic analysis and validated via PCR. Among these, the upregulation of Mcoln1 promotes autophagy, facilitating the clearance of damaged mitochondria and excessive ROS. This has been substantiated through in vitro experiments. Excessive ROS precipitates a reduction in mitochondrial membrane potential, instigating cell apoptosis. In accordance with TUNEL staining results, JFG acts to inhibit cell apoptosis. To ascertain whether Mcoln1 is a crucial target for JFG in treating VMC, Mcoln1 was suppressed in H9C2 cells. The suppression of Mcoln1 hinders the elevation in autophagy levels post-JFG treatment, obstructs the enhancement of mitochondrial function, and impedes the clearance of ROS. Furthermore, the inhibitory effect of JFG on cell apoptosis is attenuated.

CONCLUSION: The research findings indicate that JFG has a protective effect on CVB3-induced H9C2 cell injury. JFG may exert its effects in VMC treatment by enhancing autophagy to suppress cell apoptosis through the mitochondrial pathway, thereby counteracting cell damage.