ScopeIn this study, we aim to determine the effects of resveratrol (RSV) on muscle atrophy in streptozocin‐induced diabetic mice and to explore mitochondrial quality control (MQC) as a possible mechanism.Methods and resultsThe experimental mice were fed either a control diet or an identical diet containing 0.04% RSV for 8 weeks. Examinations were subsequently carried out, including the effects of RSV on muscle atrophy and muscle function, as well as on the signaling pathways related to protein degradation and MQC processes. The results show that RSV supplementation improves muscle atrophy and muscle function, attenuates the increase in ubiquitin and muscle RING‐finger protein‐1 (MuRF‐1), and simultaneously attenuates LC3‐II and cleaved caspase‐3 in the skeletal muscle of diabetic mice. Moreover, RSV treatment of diabetic mice results in an increase in mitochondrial biogenesis and inhibition of the activation of mitophagy in skeletal muscle. RSV also protects skeletal muscle against excess mitochondrial fusion and fission in the diabetic mice.ConclusionThe results suggest that RSV ameliorates diabetes‐induced skeletal muscle atrophy by modulating MQC.

The aim of this study was to investigate the effect and possible mechanism of Astragaloside IV (AS-IV) on retarding the progression of diabetic nephropathy (DN) in a type 2 diabetic animal model, db/db mice. Eight-week-old male db/db diabetic mice and their nondiabetic littermate control db/m mice were used in the present study. AS-IV was administered to the db/db mice by adding it to standard feed at a dose of 1g/kg for 12 weeks. Renal injury was assessed by urinary albumin excretion (UAE) and Periodic acid-Schiff staining. The protein expression levels of mitochondrial quality-control-associated proteins were evaluated using Western blotting and immunohistochemical staining analysis. At the end of the experiment, db/db mice showed overt renal injury, as evidenced by increased UAE, increased urinary N-acetyl-β-D-glucosaminidase (NAG), expansion of mesangial matrix, and increased renal tubular area. AS-IV administration significantly reduced UAE and urinary NAG and ameliorated the renal pathologic injury seen in db/db mice. Furthermore, the expression of dynamin-related protein 1 (Drp-1), mitochondrial fission protein 1 (Fis-1), and mitochondrial fission factor (MFF), the main regulators of mitochondrial fission, was significantly increased in db/db mice. Moreover, PTEN-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy was abnormally activated in db/db mice. AS-IV significantly reduced renal Drp-1, Fis-1, and MFF expression and downregulated PINK1/Parkin-mediated mitophagy in db/db mice. However, mitochondrial biogenesis and mitochondrial fusion-associated protein levels were not significantly different between db/m and db/db mice in our study, with or without AS-IV treatment. In conclusion, administration of AS-IV could retard DN progression in type 2 diabetes mice, which might be associated with restoration of the mitochondrial quality control network.

Diabetic nephropathy is a lethal complication of diabetes mellitus and a major type of chronic kidney disease. Dysregulation of the Akt pathway and its downstream cascades, including mTOR, NFκB, and Erk1/2, play a critical role in the development of diabetic nephropathy. Astragaloside IV is a major component of Huangqi and exerts renal protection in a mouse model of type 1 diabetes. The current study was undertaken to investigate the protective effects of diet supplementation of AS-IV on renal injury in db/db mice, a type 2 diabetic mouse model. Results showed that administration of AS-IV reduced albuminuria, ameliorated changes in the glomerular and tubular pathology, and decreased urinary NAG, NGAL, and TGF-β1 in db/db mice. AS-IV also attenuated the diabetes-related activation of Akt/mTOR, NFκB, and Erk1/2 signaling pathways without causing any detectable hepatotoxicity. Collectively, these findings showed AS-IV to be beneficial to type 2 diabetic nephropathy, which might be associated with the inhibition of Akt/mTOR, NFκB and Erk1/2 signaling pathways.

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ObjectiveThe aim of this study was to investigate the renoprotective effects and molecular mechanisms of astragaloside IV (AS-IV) in streptozotocin (STZ)-induced diabetic mice.MethodsMale C57BL/6 mice were injected intraperitoneally with STZ at 200 mg/kg body weight. AS-IV was administered for 8 consecutive weeks, beginning 1 week after STZ injection. Body weight, 24-hour urinary albumin excretion, and fasting blood glucose were measured. Kidney tissues were examined by histopathological analyses. Total levels and phosphorylation of mitogen-activated protein kinase 1/2 (MEK1/2), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and ribosomal S6 kinase 2 (RSK2) were determined by Western blotting analysis.ResultsAS-IV treatment significantly reduced albuminuria and serum creatinine levels, ameliorated mesangial matrix expansion and greater foot process width, and decreased the levels of urinary N-acetyl-beta-D-glucosaminidase, neutrophil gelatinase-associated lipocalin, and transforming growth factor-beta 1 in STZ-induced diabetic mice. AS-IV also inhibited renal cortical phosphorylation of MEK1/2, ERK1/2 and RSK2.ConclusionOur results suggest that AS-IV attenuates renal injury in STZ-induced diabetic mice. This effect might be partially associated with inhibition of the activation of the MEK1/2-ERK1/2-RSK2 signaling pathway.

Aims: To investigate the potential role of renalase in adriamycin nephropathy and the effect of lisinopril on the regulation of renalase. Methods: Adriamycin nephropathy was induced in male Wistar rats (n=12) by a single injection of adriamycin at 2 mg/kg body weight. Rats were then randomly assigned to a model group or a treatment group, to which were administered distilled water or the angiotensin converting enzyme inhibitor lisinopril, respectively, for 12 weeks. Six normal rats served as controls. At the end of study, physiological parameters and systolic blood pressure were measured. Glomerulosclerosis and tubulointerstitial injury were assessed by histopathology Renalase protein expression in kidney was quantified by immunohistochemistry and immunoblotting. The serum concentration and urinary excretion of renalase were determined by enzyme-linked immunosorbent assay. Results: In model group rats, proteinuria and systolic blood pressure were elevated. Increased serum renalase concentration was observed; however, renalase protein expression in the kidney was significantly decreased. Compared with the model group, decreased proteinuria, lower systolic blood pressure, and fewer morphologic lesions were detected in the treatment group. Although levels of serum renalase were similar, accumulation of renalase in urine and kidney tissue increased notably in the treatment group compared with the model group. Conclusions: This study suggests that renalase may be involved in the process of adriamycin-induced renal injuries. Lisinopril may attenuate adriamycin-induced kidney injury by controlling blood pressure, which may be partially attributed to the renalase expression and secretion.

The kidney is a high-energy demand organ rich in mitochondria especially renal tubular cells. Emerging evidence suggests that mitochondrial dysfunction, redox imbalance and kidney injury are interconnected. Artemether has biological effects by targeting mitochondria and exhibits potential therapeutic value for kidney disease. However, the underlying molecular mechanisms have not been fully elucidated. This study was performed to determine the effects of artemether on Adriamycin-induced nephropathy and the potential mechanisms were also investigated. In vivo, an Adriamycin nephropathy mouse model was established, and mice were treated with or without artemether for 2 weeks. In vitro, NRK-52E cells were stimulated with TGF-β1 and treated with or without artemether for 24 h. Then renal damage and cell changes were evaluated. The results demonstrated that artemether reduced urinary protein excretion, recovered podocyte alterations, attenuated pathological changes and alleviated renal tubular injury. Artemether also downregulated TGF-β1 mRNA expression levels, inhibited tubular proliferation, restored tubular cell phenotypes and suppressed proliferation-related signalling pathways. In addition, artemether restored renal redox imbalance, increased mtDNA copy number and improved mitochondrial function. In summary, we provided initial evidence that artemether ameliorates kidney injury by restoring redox imbalance and improving mitochondrial function in Adriamycin nephropathy in mice. Artemether may be a promising agent for the treatment kidney disease.

Diabetes is a worldwide metabolic disease with rapid growing incidence, characterized by hyperglycemia. Diabetic kidney disease (DKD), the leading cause of chronic kidney disease (CKD), has a high morbidity according to the constantly increasing diabetic patients and always develops irreversible deterioration of renal function. Though different in pathogenesis, clinical manifestations, and therapies, both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) can evolve into DKD. Since amino acids are both biomarkers and causal agents, rarely report has been made about its metabolism which lies in T1DM- and T2DM-related kidney disease. This study was designed to investigate artemether in adjusting renal amino acid metabolism in T1DM and T2DM mice. Artemether was applied as treatment in streptozotocin (STZ) induced T1DM mice and db/db T2DM mice, respectively. Artemether-treated mice showed lower FBG and HbA1c and reduced urinary albumin excretion, as well as urinary NAG. Both types of diabetic mice showed enlarged kidneys, as confirmed by increased kidney weight and the ratio of kidney weight to body weight. Artemether normalized kidney size and thus attenuated renal hypertrophy. Kidney tissue UPLC-MS analysis showed that branched-chain amino acids (BCAAs) and citrulline were upregulated in diabetic mice without treatment and downregulated after being treated with artemether. Expressions of glutamine, glutamic acid, aspartic acid, ornithine, glycine, histidine, phenylalanine and threonine were decreased in both types of diabetic mice whereas they increased after artemether treatment. The study demonstrates the initial evidence that artemether exerted renal protection in DKD by modulating amino acid metabolism.