Inhibition of Drp1- Fis1 interaction alleviates aberrant mitochondrial fragmentation and acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is a common clinical disorder with complex etiology and poor prognosis, and currently lacks specific and effective treatment options. Mitochondrial dynamics dysfunction is a prominent feature in AKI, and modulation of mitochondrial morphology may serve as a potential therapeutic approach for AKI. METHODS: We induced ischemia-reperfusion injury (IRI) in mice (bilateral) and Bama pigs (unilateral) by occluding the renal arteries. ATP depletion and recovery (ATP-DR) was performed on proximal renal tubular cells to simulate in vitro IRI. Renal function was evaluated using creatinine and urea nitrogen levels, while renal structural damage was assessed through histopathological staining. The role of Drp1 was investigated using immunoblotting, immunohistochemistry, immunofluorescence, and immunoprecipitation techniques. Mitochondrial morphology was evaluated using confocal microscopy. RESULTS: Renal IRI induced significant mitochondrial fragmentation, accompanied by Dynamin-related protein 1 (Drp1) translocation to the mitochondria and Drp1 phosphorylation at Ser616 in the early stages (30 min after reperfusion), when there was no apparent structural damage to the kidney. The use of the Drp1 inhibitor P110 significantly improved kidney function and structural damage. P110 reduced Drp1 mitochondrial translocation, disrupted the interaction between Drp1 and Fis1, without affecting the binding of Drp1 to other mitochondrial receptors such as MFF and Mid51. High-dose administration had no apparent toxic side effects. Furthermore, ATP-DR induced mitochondrial fission in renal tubular cells, accompanied by a decrease in mitochondrial membrane potential and an increase in the translocation of the pro-apoptotic protein Bax. This process facilitated the release of dsDNA, triggering the activation of the cGAS-STING pathway and promoting inflammation. P110 attenuated mitochondrial fission, suppressed Bax mitochondrial translocation, prevented dsDNA release, and reduced the activation of the cGAS-STING pathway. Furthermore, these protective effects of P110 were also observed renal IRI model in the Bama pig and folic acid-induced nephropathy in mice. CONCLUSIONS: Dysfunction of mitochondrial dynamics mediated by Drp1 contributes to renal IRI. The specific inhibitor of Drp1, P110, demonstrated protective effects in both in vivo and in vitro models of AKI.

Tea Consumption Is Associated with Decreased Disease Activity of Rheumatoid Arthritis in a Real-World, Large-Scale Study.

INTRODUCTION: The role of tea consumption on rheumatoid arthritis (RA) has been studied in recent years, but no clear conclusion has been drawn as a result of small sample size of the studies or the fact that only in vitro studies have been performed. OBJECTIVES: The aim of this study was to explore the possible association of tea consumption with RA through a large-scale, real-world study. METHODS: A total of 733 RA patients were investigated from June to December, 2016. The disease activity of RA was assessed according to disease activity score 28-erythrocyte sedimentation rate. The amount and types of tea consumption were recorded by on-site self-administered questionnaires. Logistic regression models were applied to analyze the correlation between tea consumption and disease activity, adjusting for demographics, clinical and laboratory factors. RESULTS: There was an inverse association between tea consumption and disease activity in RA patients (OR 0.66, 95% CI 0.46-0.94). Compared with non-tea drinkers, a higher-intake of tea (>750 mL/day) was associated with lower disease activity of RA (OR 0.39, 95% CI 0.19-0.79), but not low-intake (≤750 mL/day; OR 0.83, 95% CI 0.42-1.63). A significant dose-response association was found between the amount of tea consumption and disease activity (p for trend <0.01). Further hierarchical regression analysis showed that such inverse associations were mainly present in female patients (p = 0.004), non-smokers (p = 0.01) or elders (≥60 years; p = 0.01). CONCLUSION: Tea consumption is associated with decreased disease activity of RA, suggesting the potential beneficial effect of tea in the disease.