PPARγ agonism ameliorates acute kidney injury by inhibiting neutrophil extracellular trap formation-mediated renal tubular epithelial cell PANoptosis.

BACKGROUND: Cisplatin (CP)-induced nephrotoxicity is a major clinical concern. Emerging evidence has revealed the critical role of PANoptosis, a coordinated cell death pathway, and neutrophil extracellular traps (NETs) in renal tubular damage. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) has been recognized as a potential modulator of inflammation and cell survival; however, its regulatory function and mechanism in acute kidney injury (AKI), especially CP-induced AKI, particularly concerning NETs and PANoptosis, remain poorly understood. This study investigates the central role of PPARγ and explores the therapeutic potential of its novel activator, O-alkyl and o-benzyl hesperetin derivative-1 L (HD-1L), in this context. METHODS: Cultured renal tubular epithelial cells (mTECs) as well as a CP-induced AKI mouse model (20 mg/kg, 72 h) and renal ischemia-reperfusion injury (IRI) model​ were used. PPARγ heterozygous knockout mice, NET inhibitors (DNase I and GSK484), and pharmacological interventions (including the novel PPARγ agonist HD-1L and rosiglitazone [ROSI]) were used. The molecular mechanisms were assessed using western blotting, immunofluorescence (IF), enzyme-linked immunosorbent assay (ELISA), and cellular thermal shift assays (CETSA). PPARγ activity, NET markers (MPO, Cit-H3, and dsDNA), PANoptosis-related proteins (p-MLKL, GSDMD-N, and cleaved caspase-3), and reactive oxygen species (ROS) levels were quantified. RESULTS: CP triggered robust PANoptosis in the renal tissues, accompanied by elevated NETs and ROS-dependent NETosis. PPARγ activation significantly suppressed ROS production in neutrophils, thereby reducing NET formation. Mechanistically, NETs facilitate the release of cytoplasmic dsDNA, activate the AIM2 inflammasome, and promote PANoptosome assembly. Genetic PPARγ heterozygous knockout exacerbated renal injury and abolished protective effects, confirming the central role of PPARγ. HD-1L-induced activation of PPARγ reduced markers of PANoptosis and improved renal function in CP-AKI models. Furthermore, PPARγ agonism similarly protected against renal injury and suppressed the NETosis-PANoptosis axis in the IRI model. CONCLUSION: PPARγ is a pivotal checkpoint in CP-AKI by inhibiting ROS-NETosis-driven AIM2-mediated PANoptosis. This protective mechanism is also applicable to IRI-induced AKI, highlighting its broad relevance. HD-1L confers renoprotection through PPARγ activation, providing a novel therapeutic strategy against AKI.