sEH inhibition attenuates mtROS-mediated NLRP3 inflammasome activation by promoting mitophagy in tubular epithelial cells in diabetic kidney disease.

Inflammation is a key driver of diabetic kidney disease (DKD) progression, with the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome representing a promising therapeutic target. Soluble epoxide hydrolase (sEH), an enzyme that inactivates renoprotective epoxyeicosatrienoic acids into less active diols, has been implicated in renal pathophysiology. This study investigated the role of sEH in renal tubular NLRP3 inflammasome activation and its underlying mechanisms in DKD. We observed upregulated sEH expression in high glucose (HG)-stimulated human proximal tubular epithelial (HK-2) cells and diabetic kidneys. Pharmacological inhibition of sEH attenuated diabetes-induced mitochondrial damage, mitochondrial reactive oxygen species (mtROS) production, NLRP3 inflammasome activation, and renal dysfunction both in vivo and in vitro. Furthermore, sEH inhibition restored autophagy flux and enhanced PINK1/Parkin mediated-mitophagy. Activation of mitophagy by the autophagy inducer rapamycin (Rapa) alleviated HG-induced mitochondrial impairment, mtROS overproduction, and NLRP3 inflammasome activation in HK-2 cells, suggesting that the anti-inflammatory effect of sEH inhibition is mediated through mitophagy regulation. Further mechanistic studies indicated that sEH inhibition promotes mitophagy, thereby improving mitochondrial function, reducing mtROS generation, and subsequently suppressing mtROS-dependent NLRP3 inflammasome activation in DKD. In conclusion, our findings establish a novel link between sEH and NLRP3 inflammasome activation in DKD pathogenesis, highlighting sEH inhibition as a promising therapeutic strategy for DKD treatment.