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Objective:To explore the role and mechanism of nuclear receptor subfamily 4 group A member 1 ( NR4A1) in suppressing cisplatin nephrotoxicity. Methods:The expression of NR4A1 gene in renal cell subpopulations was analyzed using the "Tabula-muris" single cell transcriptome sequencing database. NR4A1 gene was over-expressed by lentivirus infection in HK-2 cell line and primary renal proximal tubular epithelial cells. Cell counting kit-8 was used to detect the cytotoxicity of cisplatin. The cell death ratio was analyzed using propidium iodide (PI) staining by flow cytometry. The expression of NR4A1 and nuclear factor erythroid 2-related factor 2 ( NRF2) was detected by real-time fluorescent quantitative PCR and Western blotting. Ferroptosis was analyzed by detecting the contents of malondialdehyde (MDA), oxidized glutathione (GSSG) and lipid reactive oxygen species (ROS). Results:The single cell transcriptome sequencing database showed that NR4A1 gene was the lowest expression in renal proximal tubular epithelial cell subsets. Cisplatin (50 μmol/L or 100 μmol/L) could significantly induce MDA, GSSG and lipid ROS production in renal proximal tubular epithelial cells (all P<0.01), and higher cisplatin concentration accompanied with a more increase of MDA, GSSG and lipid ROS. Compared with the control HK-2 cells, the lipid ROS content and iron ion content of HK-2 cells over-expressing NR4A1 were significantly lower (all P<0.01), and the over-expression of NR4A1 inhibited cisplatin-induced cytotoxicity and ferroptosis in renal proximal tubular epithelial cells. Mechanistically, NR4A1 up-regulated the expression of anti-ferroptosis gene NRF2 in proximal renal tubular epithelial cells ( P<0.01). Furthermore, single cell data analysis showed that, similar to the expression of NR4A1 in renal tissue subsets, NRF2 was also the lowest in renal proximal tubular epithelial cells. Conclusions:Cisplatin can induce ferroptosis of renal proximal tubular epithelial cells in a dose-dependent manner. NR4A1 can inhibit cisplatin-induced ferroptosis by up-regulating NRF2 in renal proximal tubular epithelial cells, thereby alleviating the cytotoxicity of cisplatin.
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Abstract Polymyxins are antibiotics developed in the 1950s. Polymyxin-induced neurotoxicity has been often described in medical literature. The same cannot be said of nephrotoxicity or tubulopathy in particular. This report describes the case of a patient prescribed polymyxin B to treat a surgical wound infection, which led to significant increases in fractional excretion of calcium, magnesium, and potassium and subsequent persistent decreases in the levels of these ions, with serious consequences for the patient. Severe hypocalcemia, hypomagnesemia, and hypokalemia may occur during treatment with polymyxin. Calcium, magnesium and potassium serum levels must be monitored during treatment to prevent life-threatening conditions.
Resumo Polimixinas são um grupo de antibióticos desenvolvidos na década de 1950. Seus efeitos neurotóxicos são comumente descritos na literatura, porém há menos relatos sobre seus efeitos nefrotóxicos, especialmente tubulopatias. O objetivo deste relato é descrever o uso de polimixina B em uma paciente para tratamento de infecção de ferida operatória, promovendo grande aumento das frações de excreção de cálcio, magnésio e potássio e acarretando reduções graves e persistentes desses íons, com sérias consequências para a paciente. Hipocalcemia, hipomagnesemia e hipocalemia severas podem ocorrer durante terapia com polimixina e é sugerido que sejam monitorizadas as concentrações séricas desses eletrólitos durante o tratamento como forma de evitar condições de risco à vida.
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Abstract Introduction: Tubular damage is common in glomerular diseases (GD). Glycosuria is a marker of tubular dysfunction and may be used to detect tubular lesion and CKD progression. The aim of this study was to evaluate the prevalence and prognostic value of glycosuria at the time of diagnosis in primary glomerulopathies (PG). Methods: We conducted a 24-month retrospective study in patients diagnosed with PG in our center between 2009 and 2020. We excluded diabetic patients, use of SGLT2 inhibitors, transplant patients, and secondary GD. Patients were divided in two groups according to their glycosuria status at diagnosis. Results: We studied 115 patients. Global prevalence of glycosuria was 10% (n=11) and membranous nephropathy (MN) had the highest prevalence (n=5, 17.9%). We found that patients with glycosuria had higher serum creatinine (2.4 vs. 1.2 mg/dL, p=0.030), higher albuminuria (4.8 vs. 1.9 g/g, p=0.004), and lower serum albumin (2.3 vs. 3.2 g/dL, p=0.021). We did not find association with histological prognostic factors. At the end of follow-up, patients with glycosuria had higher prevalence of the composite outcome of stage 5D CKD or 50% increase in basal SCr (45.5% vs. 17.3%, p=0.037). In patients with MN, results were similar but we were able to find an association of glycosuria with more severe interstitial fibrosis and tubular atrophy (25.0 vs. 0.0 %, p=0.032). Conclusion: Ten percent of our patients with PG have glycosuria. Glycosuria at the time of diagnosis was associated with more severe clinical presentation and worst renal outcome. The association with higher albuminuria suggests that tubular function has an impact on the severity and outcomes of PG.
Resumo Introdução: Danos tubulares são comuns em doenças glomerulares (DG). Glicosúria é um marcador de disfunção tubular e pode detectar lesão tubular e progressão da DRC. O objetivo deste estudo foi avaliar a prevalência e o valor prognóstico da glicosúria no diagnóstico em glomerulopatias primárias (GP). Métodos: Realizamos estudo retrospectivo de 24 meses em pacientes diagnosticados com GP em nosso centro entre 2009-2020. Excluímos pacientes diabéticos, uso de inibidores de SGLT2, pacientes transplantados e DG secundárias. Os pacientes dividiram-se em dois grupos de acordo com seu estado de glicosúria no diagnóstico. Resultados: Estudamos 115 pacientes. A prevalência global de glicosúria foi de 10% (n=11) e a nefropatia membranosa (NM) teve maior prevalência (n=5, 17,9%). Constatamos que pacientes com glicosúria apresentavam creatinina sérica mais elevada (2,4 vs. 1,2 mg/dL, p=0,030), albuminúria mais alta (4,8 vs. 1,9 g/g, p=0,004), e albumina sérica mais baixa (2,3 vs. 3,2 g/dL, p=0,021). Não encontramos associação com fatores prognósticos histológicos. Ao final do acompanhamento, pacientes com glicosúria tiveram maior prevalência do desfecho composto de DRC estágio 5D ou aumento de 50% na CrS basal (45,5% vs. 17,3%, p=0,037). Em pacientes com NM, os resultados foram semelhantes, mas encontramos uma associação de glicosúria com fibrose intersticial mais grave e atrofia tubular (25,0 vs. 0,0 %, p=0,032). Conclusão: 10% de nossos pacientes com GP têm glicosúria. A glicosúria no diagnóstico foi associada a uma apresentação clínica mais grave e pior desfecho renal. A associação com albuminúria mais elevada sugere que a função tubular tem um impacto na gravidade e nos desfechos da GP.
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Objective:To compare aging models for renal tubular epithelial cells induced by different drugs.Methods:Different concentrations of D-galactose(D-gal), hydrogen peroxide(H 2O 2)and cisplatin(CDDP)were administered to the human proximal tubular epithelial cell line(HK2). Cell activity and the half maximal inhibitory concentration(IC50)were measured by the CCK-8 assay; cell senescence was assessed by senescence-related β-galactosidase staining(SA-β-gal); senescence-related gene expression was detected by Western blotting; cell cycle distribution and apoptosis were determined by flow cytometry.Pathological changes in renal tubules and interstitial tissues were examined in D-gal-induced and naturally aging mice using HE staining, and p16 expression was detected using immunohistochemistry. Results:CCK-8 assay results showed that HK2 cell activity was inhibited treatment with each of the three compounds.The 48-hour IC50 values were(365.8±9.7)mmol/L for D-gal, (385.4±20.8)μmol/L for H 2O 2 and(8.4±1.6)μmol/L for CDDP.Light microscopic observation revealed slowed growth of HK2 cells in the three groups.The rate of SA-β-gal-positive cells increased, compared with the control group( P<0.05). Treatment resulted in an increase in G0/G1 phase cells by(22.9±1.0)% in the 400 mmol/L D-gal group and by(13.0±4.4)% in the 400 μmol/L H 2O 2 group, while G2/M phase cells increased by(14.4±1.9)%( t=48.07, 6.40, 16.53, P<0.05)in the 8 μmol/L CDDP group, compared with the control group.Also, compared with the control group, HK2 cell apoptosis increased by(50.3±1.0)% in the 400 μmol/L H 2O 2 group and by(41.9±2.0)% in the 8 μmol/L CDDP group, which was significantly higher than(7.7±0.4)% in the 400 mmol/L D-gal group( t=77.47, 33.73, 28.35, all P<0.05). Western blotting results indicated that the expression of CCND1 was down-regulated after any of the three drugs reached a certain concentration.The expression of p16 in the D-gal group was up-regulated( F=92.88, P<0.05), but there was no statistical difference in the expression of p16 after H 2O 2 or CDDP treatment.Mice of the D-gal model showed a decline in renal tubular cells, thickened basement membrane, widened interstitial spaces and increased expression of p16 in renal tubules similar to those observed in naturally aging mice. Conclusions:For HK2 cell senescence models induced by three different drugs, the renal tubular epithelial cell senescence model induced by D-gal is relatively close to the natural senescence model.
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Objective To investigate effects of albumin overload on mitochondrial membrane potential and ultrastructural changes in renal tubular epithelial cells (HK-2).Methods Vitrocultured HK-2 cells were treated with different concentrations of albumin.The mitochondrial membrane potential in HK-2 cells was detected by fluorescence probe JC-1,and the electron microscopy was used to detect the mitochondrial ultrastructure of cells.Results JC-1-detected red/green ratio was 2.34 ± 0.21 at 0 g/L of albumin treatment,0.83 ± 0.09 at 4 g/L,0.41 ± 0.07 at 8 g/L,0.38± 0.08 at 16 g/L albumin overload,which showed a gradually decreased red and green fluorescence intensity ratio along with increased albumin overload(F =162.794,P ＜0.001),and with significant differences in the ratio among groups (all P ＜ 0.05).Albumin overload-induced mitochondrial abnormality in transmission electron microscope included mitochondrial swelling,disordered cristae arrangement,cristae lysis and cavitation,and the increase of bilayer membrane structures in HK-2 cells.Conclusions Albumin overload can induce the decline of mitochondrial membrane potential,mitochondrial damage and autophagy in renal tubular epithelial cells,which suggest that mitochondrial damage and autophagy may be one of the mechanisms of albumin overloadinduced renal tubular epithelial cell injury.
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Objective To explore the expression profile of Wnt4 in rat kidney during renal development and its effect on renal development. Methods Rats with embryonic age of 18 days (E 18 d) , 20 days (E 20 d) as well as postnatal age of 0 day (P 0 d), 1 day (P 1 d), 3 days (P 3 d), 5 days (P 5 d) and 7 days (P 7 d) were selected. Expression levels of Wnt4 in rat kidney during renal development were quantified by immunohistochemistry and Western blot in all time points. Results Immuno?histochemistry analysis showed that during E 18 d to P 7 d, Wnt4 mainly expressed in proximal tubules, ureteric bud, comma shaped bodies and S shaped bodies of nephrogenic zone;the expression in the distal tubule was weak;the expression in renal corpuscle decreased with time;Western blot analysis showed that the expression of Wnt4 in rat kidney began to decrease from E 18 d and reached bottom at P 1 d then rise again until P 7 d when it dropped again. Conclusion During renal development, Wnt4 proteins were involved in the development of the nephrogenic zone through regulating canonical Wnt/β-catenin signaling pathway, and was involved in extension of proximal tubules by inducing the non canonical Wnt/PCP signaling pathway. Expression of Wnt4 protein in rat kidney was closely related to nephron formation and development of proximal tubules.
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Objective To investigate the value of urinary trehalase (T) in patients with renal proximal tubular damage.Methods 134 patients with kidney disease (male:66 female:68 age:18-59 ; 31cases with acute renal failure,30 cases with chronic renal failure,20 cases with drug-induced renal impairment,21 cases with renal transplantation and 32 cases with nephritic syndrome) and 101 healthy controls (58 males and 43 females) were selected.Urinary T,N-acetyl-D-glucosaminidase (NAG),β2-MG,gamma-glutamyl transferase (GGT) were detected.Data were analyzed by SPSS 11.5,including nonparametric rank test,ROC analysis.Results The level of urinary trehalase in control group was normally distributed (7.1 ± 4.1) μmol/h · g Cr (0-25 μmol/h · g Cr).There was no significant difference between men and women (t =0.63,P =0.53).Urinary T levels were significant higher in all kidney disease groups than in control group (Z =6.80,5.90,5.23,6.00,8.04,P ＜0.01).According to ROC curve,the area of urinary T under the ROC curve (AUC) in 134 patients was 0.9,significantly different with NAG,β2-MG,GGT area (P ＜ 0.01),the AUCs of T were 0.94,0.85,0.90,0.90,0.91 in acute and chronic renal failure group,drug-induced renal impairment group,renal transplantation group and nephritic syndrome group,respectively; Youden index were 0.85,0.65,0.77,0.66,0.72 respectively.Corresponding to the Youden index,sensitivity and specificity were 90.3％ and 95.1％,73.3％ and 92.1％,85.0％ and 92.1％,81.0％ and 85.2％,87.5％ and 84.2％ respectively.Conclusions The Urinary trehalase is better than other markers in the diagnosis of the proximal renal tubular damage.It was better to evaluate the proximal tubular function early in time.The diagnostic value of urinary trehalase played a key role in diagnosis,treatment and prognosis of kidney diseases.
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The nephrotoxicity of gentamicin (GM) has been widely recognized. Heat shock protein 72 (HSP72) has been reported to be a cytoprotectant. However, its cytoprotective effect against GM induced kidney injury has not yet been studied. In this study, we investigated the cytoprotective effect of HSP72 on GM-induced nephrotoxicity in vitro. Human Kidney tubular cell line, HK-2 cells were divided into four groups: control group, GM group (cells incubated with GM only), heat shock (HS) group (cells incubated at 43 degrees C for 30 min), and GM plus HS group, respectively. Lactate dehydrogenanse (LDH) release increased time-dependently from 24 hr to 96 hr compared to the data of cells treated with GM only. Results of NAG activities, superoxide dismutase (SOD) activities and malondialdehyde (MDA) content were similar to that of the LDH release. The amount of HSP72 positive cells increased significartly at 72 hr after cells were treated with GM only. Both HSP72 protein and gene expression increased significantly at 72 hr when cells were treated with GM. On the other hand, HS induced HSP72 expression markedly. Pretreatment of HS inhibited HK-2 cells from GM-induced injury. It could reduce LDH release and NAG activity. HS also increased SOD activity, and decreased MDA content when cells were damaged by GM. These findings suggested that HS may protect kidney cells from GM-induced injury. Pre-induction of HSP72 may provide therapeutic strategies for nephrotoxicity induced by GM.
Subject(s)
Humans , Reactive Oxygen Species/metabolism , RNA, Messenger/analysis , Oxidation-Reduction , L-Lactate Dehydrogenase/metabolism , Kidney Tubules, Proximal/chemistry , Hot Temperature , HSP72 Heat-Shock Proteins/analysis , Gentamicins/toxicity , Cytoprotection , Cells, CulturedABSTRACT
AIM: To investigate the effect of high glucose concentration on serum and glucocorticoid induced protein kinase (SGK) mRNA and protein expressions in human proximal tubular epithelial cells (HKC) and the possible role of SGK in the production of extracellular matrix (ECM) of HKC under the condition of high glucose. METHODS: HKC was divided into 3 groups: control glucose group (CG group, 5 5 mmol/L D-glucose); high glucose group (HG group, 25 mmol/L D-glucose) and osmotic control group (MG group, 19 5 mmol/L mannitol and 5 5 mmol/L D-glucose). The expressions of SGK mRNA and protein were assessed by semi-quantitative RT-PCR and Western blotting respectively. The level of secretary and cytoplasmic fibronectin (FN) were detected by enzyme-linked immunoabsordent assay (ELISA) and indirect-immunofluorescence. RESULTS: HKC expressed SGK1, SGK2 and SGK3 at mRNA and protein levels. Their mRNA level were up-regulated since 2 hours after cells exposed to D-glucose and this up-regulation persisted to the end of 8th hour, and SGK1 protein level elevated simultaneously. On the other hand, the increased FN secretion by high glucose was in a time-dependent manner and its improved secretion threshold was just followed by the high expression of SGK1. CONCLUSIONS: In response to high glucose, the expression of SGK1, SGK2 and SGK3 in human proximal tubular epithelial cells were up-regulated which was accompanied with FN accumulation. The high expression of SGK may mediate overproduction of ECM in proximal tubular epithelial cells and contribute to the diabetic nephropathy.