Research Article: Capsaicin ameliorates diabetic nephropathy by targeted activation of GPX4 and inhibition of pyroptosis
Abstract:
Capsaicin (CAP) is the primary pungent alkaloid found in chili peppers. The aim of this study is to screen for candidate therapeutic agents targeting the mitochondrial dysfunction–pyroptosis axis in diabetic nephropathy (DN) and to validate the efficacy and mechanism of action of capsaicin.
Bioinformatics analysis was conducted to identify candidate genes and drugs. The protective effects and underlying mechanisms of CAP were investigated using a high-glucose (HG)-induced HK-2 cell model and a streptozotocin-induced T1DM DN rat model. Experimental techniques included CCK8 assay, flow cytometry (pyroptosis and ROS), JC-1 staining, Western blot analysis, and histopathological staining. GPX4-IN-3 was applied in vivo and in vitro to determine whether it reversed the protective effects of capsaicin. The data were analyzed using the Shapiro–Wilk test, one-way analysis of variance (ANOVA) with corresponding post-hoc tests, and correlation analysis.
Bioinformatic analysis identified 12 intersecting genes and highlighted CAP as a potential GPX4-targeting compound. Molecular docking demonstrated a high binding affinity of CAP for GPX4 and caspase-9. In vitro , CAP dose-dependently restored cell viability and suppressed HG-induced pyroptosis in HK-2 cells. It significantly alleviated mitochondrial damage by reducing ROS production, restoring mitochondrial membrane potential, and improving mitochondrial ultrastructure. Notably, these protective effects were reversed by GPX4-IN-3. Western blot analysis revealed that CAP upregulated GPX4 expression and inhibited activation of the NLRP3/caspase-1/GSDMD-N pyroptosis pathway. In vivo , CAP treatment markedly improved renal histopathology and renal function in DN rats; however, these effects were attenuated by co-administration of GPX4-IN-3.
This study demonstrates that CAP ameliorates diabetic renal injury by targeting GPX4, thereby mitigating mitochondrial dysfunction and subsequent NLRP3-mediated pyroptosis. These findings validate the bioinformatic prediction and reveal a novel mechanism of action for CAP, positioning it as a promising therapeutic candidate for DN.
Introduction:
Diabetes mellitus has become a global public health crisis. Among the subtypes of diabetes, type 2 diabetes (T2DM) accounts for the vast majority of cases, with over 537 million adults worldwide suffering from it ( 1 ); while type 1 diabetes (T1DM) is a chronic autoimmune disease, although its incidence is relatively low, it is still on the rise ( 2 , 3 ). Among them, diabetic nephropathy (DN) has become the leading cause of end - stage renal disease (ESRD) globally, posing an increasingly severe public health…
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