G‑Protein-Coupled Receptor 41 (GPR41) as a Therapeutic Target for Metabolic Endotoxemia: Mechanistic Insights into AR420626-Induced Autophagy and Nuclear Factor kappa B (NF-κB) Suppression.

G-protein-coupled receptor 41 (GPR41/FFAR3) functions as a crucial metabolic sensor of gut microbiota-derived short-chain fatty acids (SCFAs). However, the precise mechanisms by which GPR41 suppresses metabolic endotoxemia caused by translocation of gut-derived lipopolysaccharide (LPS) into the circulation remain unclear. In this study, we investigated the protective effects of AR420626 (AR), a selective GPR41 agonist, against endotoxemia using RAW 264.7 macrophages to mimic an endotoxin stress environment. Our results showed that AR-induced activation of GPR41 significantly suppressed the production of nitric oxide (NO) and interleukin-6 (IL-6), key pro-inflammatory mediators implicated in the pathogenesis of endotoxemia, through inhibition of the nuclear factor kappa B (NF-κB) signaling pathway. In addition, AR-mediated GPR41 activation significantly reduced the expression of monocyte chemoattractant protein-1 (MCP-1) and inducible nitric oxide synthase (iNOS). These protective effects were mechanistically linked to enhanced autophagic activity, as evidenced by increased conversion of LC3-I to LC3-II. Importantly, pharmacological inhibition of autophagy abolished the ability of AR to suppress NF-κB activation, suggesting that the GPR41-autophagy axis is essential for preserving macrophage homeostasis against LPS-induced endotoxemia damage. Furthermore, GPR41 knockdown markedly abrogated the AR-mediated regulation of iNOS, phosphorylated NF-κB, and p62 under LPS stimulation, confirming that these protective effects are specifically mediated through GPR41. These results suggest that pharmacological activation of GPR41 to enhance autophagy may represent a novel therapeutic strategy for the treatment of endotoxemia.