Hyperuricemia (HUA)-induced oxidative stress is a crucial contributor to hyperuricemic nephropathy (HN), but the molecular mechanisms underlying the disturbed redox homeostasis in kidneys remain elusive. Using RNA sequencing, together with biochemical analyses, we found that nuclear factor erythroid 2-related factor 2 (NRF2) expression and nuclear localization levels were increased in early HN progression and then gradually declined below the baseline level. We identified the impaired activity of the NRF2-activated antioxidant pathway as a driver of oxidative damage in HN progression. Through nrf2 deletion, we further confirmed aggravated kidney damage in nrf2 knockout HN mice compared with HN mice. In contrast, the pharmacological agonist of NRF2 improved kidney function and alleviated renal fibrosis in mice. Mechanistically, the activation of NRF2 signaling reduced oxidative stress by restoring mitochondrial homeostasis and reducing NADPH oxidase 4 (NOX4) expression in vivo or in vitro. Moreover, the activation of NRF2 promoted the expression levels of heme oxygenase 1 (HO-1) and quinone oxidoreductase 1 (NQO1) and enhanced the antioxidant capacity of cells. Furthermore, the activation of NRF2 ameliorated renal fibrosis in HN mice through the downregulation of the transforming growth factor-beta 1 (TGF-β1) signaling pathway and ultimately delayed the progression of HN. Collectively, these results suggested NRF2 as a key regulator in improving mitochondrial homeostasis and fibrosis in renal tubular cells by reducing oxidative stress, upregulating the antioxidant signaling pathway, and downregulating the TGF-β1 signaling pathway. The activation of NRF2 represents a promising strategy to restore redox homeostasis and combat HN.

Cisplatin (Cis) is a widely used chemotherapy drug, but its nephrotoxicity limits its clinical application. Acute kidney injury (AKI) is a common complication, restricting long-term use. This study investigates the mechanisms of cisplatin-induced AKI and explores potential therapeutic targets. C57BL/6J mice were intraperitoneally injected with 20 mg/kg cisplatin to establish an AKI model. Serum creatinine, urea nitrogen, and tubular injury biomarkers (NGAL, KIM-1) progressively increased, indicating kidney dysfunction. Mitochondrial ATP levels significantly decreased, along with reduced mitochondrial fission and fusion, suggesting mitochondrial dysfunction. Increased oxidases and reduced antioxidants indicated redox imbalance, and metabolic reprogramming was observed, with lipid deposition, impaired fatty acid oxidation (FAO), and enhanced glycolysis in proximal tubular epithelial cells (PTECs). Nuclear factor erythroid 2-related factor 2 (NRF2) is a key transcriptional regulator of redox homeostasis and mitochondrial function. We found NRF2 levels increased early in AKI, followed by a decrease in vivo and in vitro, suggesting activation in the stress response. Nfe2l2 knockout mice showed aggravated kidney injury, characterized by worsened kidney function and histopathological damage. Mechanistically, Nfe2l2 knockout resulted in redox imbalance, reduced ATP synthesis, mitochondrial dysfunction and metabolic dysregulation. Furthermore, we activated NRF2 using dimethyl fumarate (DMF), observing a reduction in kidney damage and lipid deposition in mice. In conclusion, activating NRF2-dependent antioxidant pathways plays a crucial role in protecting against cisplatin-induced AKI. NRF2 may serve as a potential target for developing therapeutic strategies to prevent cisplatin nephrotoxicity.

Ascites is a typical symptom of liver cirrhosis that is caused by a variety of liver diseases. Ascites severely affects the life quality of patients and needs long-term treatment. 25a is a specific urea transporter inhibitor with a diuretic effect that does not disturb the electrolyte balance. In this study, we aimed to determine the therapeutic effect of 25a on ascites with a dimethylnitrosamine (DMN)-induced cirrhotic rat model. It was found that 100 mg/kg of 25a significantly increased the daily urine output by 60% to 97% and reduced the daily abdominal circumference change by 220% to 260% in cirrhotic rats with a water intake limitation. The 25a treatment kept the serum electrolyte levels within normal ranges in cirrhotic rats. The H&E and Masson staining of liver tissue showed that 25a did not change the cirrhotic degree. A serum biochemical examination showed that 25a did not improve the liver function in cirrhotic rats. A Western blot analysis showed that 25a did not change the expression of fibrosis-related marker protein α-SMA, but significantly decreased the expressions of type I collagen in the liver of cirrhotic rats, indicating that 25a did not reverse cirrhosis, but could slow the cirrhotic progression. These data indicated that 25a significantly reduced ascites via diuresis without an electrolyte imbalance in cirrhotic rats. Our study provides a proof of concept that urea transporter inhibitors might be developed as novel diuretics to treat cirrhotic ascites.

Background/Objective: Aging is a significant risk factor for chronic diseases and disability, yet effective anti-aging interventions remain elusive. We explored the potential of 3-hydroxybutyrate (3HB), an endogenous metabolite with established safety, to modulate longevity in mice. Methods: In this study, we employed 2BS and WI-38 cell models, a yeast model, and naturally aging mouse models to investigate the effects of 3HB on aging in various systems. Additionally, we utilized RNA sequencing and metabolomics technologies to explore the potential mechanisms underlying the action of 3HB. Results: Our findings demonstrate that 3HB supplementation effectively delays cellular senescence, extending yeast lifespan by 51.3% and the median lifespan of naturally senescent mice by 21.0%. Notably, 3HB prolonged healthy lifespan in mice while mitigating age-related tissue morphology changes and organ senescence. Mechanistically, we identified that 3HB’s anti-aging properties are mediated through its ability to delay cellular senescence and metabolic reprogramming, while promoting the production of beneficial metabolites like trigoneline and isoguvacine. Conclusions: These findings highlight the promising therapeutic potential of 3HB as an anti-aging intervention and provide novel insights into its underlying mechanisms.