Nobiletin ameliorates diabetic nephropathy by modulating TP53-associated PANoptosis: an experimental study

Nobiletin (NOB), a naturally occurring polymethoxyflavone enriched in Citri Reticulatae Pericarpium-the dried peel of mature citrus fruit-has attracted increasing attention because of its multi-target pharmacological activities. This study explored the protective effects of NOB on diabetic nephropathy (DN), with a focus on TP53-associated PANoptosis and TFEB-related lysosomal and energy metabolic changes.

Forty male db/db mice were randomly assigned to the model, metformin, low-dose NOB (30 mg/kg/day), and high-dose NOB (60 mg/kg/day) groups, with 10 mice per group. Ten age-matched male db/m mice served as non-diabetic controls. Treatments were administered by gavage for 8 weeks. Metabolic parameters, lipid profiles, inflammatory cytokines, renal function, histopathology, untargeted metabolomics, energy metabolites, network pharmacology, surface plasmon resonance (SPR), immunofluorescence, qPCR, and Western blot analyses were performed. Supplementary in vitro validation was performed in high-glucose-treated HK2 renal tubular epithelial cells with TP53 knockdown or overexpression.

NOB treatment reduced FBG, OGTT-AUC, INS, HOMA-IR, GSP, TC, TG, and LDL-C while increasing HDL-C. High-dose NOB improved renal function, reduced IL-1β and IL-6, and alleviated histological damage. Untargeted metabolomics suggested that NOB partially restored pathway-level changes related to oxidative phosphorylation, lysosomal function, fatty acid metabolism, and energy metabolism. Network pharmacology identified TP53 as a central candidate target, and SPR analysis suggested binding between NOB and TP53 protein. NOB treatment reduced TP53 signal, promoted TFEB nuclear localization, and suppressed pyroptosis-, apoptosis-, and necroptosis-related markers in diabetic kidneys. Representative HK2 Western blot experiments showed expression patterns consistent with attenuation of high-glucose-induced PANoptosis-related protein activation after TP53 knockdown and partial counteraction of the NOB-associated regulatory pattern after TP53 overexpression.

NOB ameliorated DN-related metabolic disturbance, inflammation, renal dysfunction, histological injury, and fibrosis. These protective effects were associated with reduced TP53 activation, restoration of TFEB-related lysosomal and energy metabolic status, and suppression of PANoptosis-related pathways. Supplementary HK2 cell experiments provided supportive, representative evidence for the involvement of TP53 in high-glucose-induced PANoptosis-related protein activation and in the regulatory effect of NOB. These findings suggest that NOB may be a promising natural compound for DN intervention.