HMGCS2 Palmitoylation Promotes Diabetes-Induced Erectile Dysfunction Through PPARα-Mediated Macrophage Extracellular Trap Formation.

INTRODUCTION

Diabetes mellitus-induced erectile dysfunction (DMED) is a prevalent complication with limited therapeutic options for non-responders to conventional treatments. Macrophage extracellular traps (METs) are implicated in various pathologies, but their role and regulatory mechanisms in DMED remain unclear. This study investigates the role of HMGCS2 palmitoylation in promoting MET formation and DMED pathogenesis through PPARα interaction.

METHODS

In vitro models were established using RAW264.7 macrophages treated with high glucose (HG) and palmitic acid (PA). A DMED rat model was induced by high-fat diet and streptozotocin injection, followed by administration of the palmitoylation inhibitor CMA (cyano-myracrylamide). HMGCS2 palmitoylation, protein expression, and its interaction with PPARα were assessed using acyl-biotin exchange (ABE) and co-immunoprecipitation (Co-IP) assays. MET formation, reactive oxygen species (ROS) production, oxidative stress markers (MDA, GSH), mitochondrial function (MMP, ATP, morphology), macrophage infiltration, and cell apoptosis were evaluated via Western blot, immunofluorescence, ELISA, transmission electron microscopy, flow cytometry, and TUNEL staining. Erectile function was assessed in vivo by apomorphine-induced penile erection tests.

RESULTS

HMGCS2 expression and palmitoylation were significantly upregulated in both HG/PA-treated macrophages and corpus cavernosum of DMED rats. CMA treatment effectively reduced HMGCS2 palmitoylation, attenuated its interaction with PPARα, and downregulated HMGCS2 expression. Consequently, pharmacological inhibition of palmitoylation suppressed HG/PA-induced MET formation, ROS overproduction, oxidative stress, and mitochondrial dysfunction in vitro. In DMED rats, CMA administration significantly improved penile erectile function, which recovered to 78% of the number of erections of the control group per unit time, as well as reduced peripheral blood PA levels, and alleviated pathological changes in corpus cavernosum. Furthermore, CMA inhibited MET formation, reduced macrophage infiltration, suppressed ROS and oxidative stress, and decreased cell apoptosis in vivo.

CONCLUSION

Our findings demonstrate that HMGCS2 palmitoylation drives DMED pathogenesis by promoting MET formation through enhanced PPARα interaction. Targeting HMGCS2 palmitoylation represents a promising therapeutic strategy for DMED.