Mitochondrial oxidative damage and apoptosis induced by high glucose through Rho kinase signal pathway in renal tubular epithelial cells

Objective:To investigate the role of oxidative stress in human renal tubular epithelial cells(HK-2)induced by high glucose and the underlying signal pathway in vitro.Methods:MYPT1,pro-caspase-3,PGC-1α,and Drpl protein expressions were measured by Western blot.MnSOD2,Drp1 and PGC-1αmRNA expressions were detected by real time PCR.Results:Results showed that high glucose significantly up-regulated the protein expressions of MYPT1,pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells;while Rho kinase inhibitor fasudil and ROCK1 siRNA inhibited protein expressions of pro-caspase-3 and the mRNA expression of MnSOD2 in HK-2 cells induced by high glucose.Importantly,fasudil and ROCK1 siRNA markedly inhibited the expressions of mitochondrial motor proteins Drp1 and mitochondrial gene PGC-la in HK-2 cell=s induced by high glucose.Conclusions:Our findings suggest that Rho kinase signal pathway is involved in mitochondrial oxidative damage and apoptosis in high glucose-induced renal tubular epithelial cells by regulating mitochondrial motor proteins Drp1 and mitochondrial gene PGC-1α.Targeting Rho kinase signal pathway might be a potential strategy for the treatment of diabetic nephropathy.

Role of Connective Tissue Growth Factor in Extracellular Matrix Degradation in Renal Tubular Epithelial Cells

In order to investigate the effects of connective tissue growth factor （CTGF） antisense oligodeoxynucleotide （ODN） on plasminogen activator inhibitor-1 （PAI-1） expression in renal tubular cells induced by transforming growth factor β1 （TGF-β1） and to explore the role of CTGF in the degradation of renal extracellular matrix （ECM）, a human proximal tubular epithelial cell line （HKC） was cultured in vitro. Cationic lipid-mediated CTGF antisense ODN was transfected into HKC. After HKC were stimulated with TGF-β1 （5 μg/L）, the mRNA level of PAI-1 was detected by RT-PCR. Intracellular PAI-1 protein synthesis was assessed by flow cytometry. The secreted PAI-1 in the media was determined by Western blot. The results showed that TGF-β1 could induce tubular CTGF and PAI-1 mRNA expression. The PAI-1 mRNA expression induced by TGF-β1 was significantly inhibited by CTGF antisense ODN. CTGF antisense ODN also inhibited intracellular PAI-1 protein synthesis and lowered the levels of PAI-1 protein secreted into the media. It was concluded that CTGF might play a crucial role in the degradation of excessive ECM during tubulointerstitial fibrosis, and blocking the biological effect of CTGF may he a novel way in preventing renal fibrosis.

The Effect of Connective Tissue Growth Factor on Human Renal Tubular Epithelial Cell Transdifferentiation

To investigate the role of connective tissue growth factor (CTGF) in transdifferentiation of human renal tubular epithelial cell (HKC), in vitro cultured HKC cells were divided into 3 groups: negtive control, low dose CTGF-treated group (rh CTGF, 2.5 ng/ml) and high dose CTGF-treated (rhCTGF, 5.0 ng/ml). Then the expression of α-smooth muscle actin (α-SMA) were assessed by indirect immuno-fluorescence, and the percentage of α-SMA positive cells were assessed by flow cytometry. RT-PCR were also performed to examine the mRNA level of α-SMA. Upon the stimulation of different concentrations of rhCTGF, the expression of α-SMA were markedly stronger than that in negative controls. The percentages of α-SMA positive cells were significantly higher in the stimulated groups than that of negative controls (38.9 %, 65.5 % vs 2.4 %, P<0.01) .α-SMA mRNA levels were also up-regulated by the stimulation of rhCTGF (P<0.01). These results suggest that CTGF can promote the transdifferentiation of human renal tubular epithelial cells towards myofibroblast (Myo-F).

Decreased TRPM7 alleviates high glucose-induced renal tubular epithelial cell injury by inhibiting the HMGB1/TLR4 signaling pathway

Objective:To explore the regulatory mechanism of transient receptor potential melastatin-7(TRPM7)in high glucose-induced renal tubular epithelial cell injury.Methods:The expression of TRPM7 in the serum of diabetic nephropathy patients and high glucose-induced HK-2 cells was detected by RT-qPCR.Then,the TRPM7 interference vector was constructed,and the downstream high mobility group box 1(HMGB1)/Toll-like receptor 4(TLR4)signaling pathway proteins were detected.Next,in addition to interference with TRPM7 expression,overexpression of HMGB1 in high glucose-induced HK-2 cells was performed.Cell activity,apoptosis,oxidative stress levels,and inflammation levels were determined by CCK8,TUNEL,Western blotting,immunofluorescence and related kits.Results:TRPM7 expression was upregulated in the serum of diabetic nephropathy patients and high glucose-induced HK-2 cells.Interference with TRPM7 reduced cell damage,epithelial-mesenchymal transition,oxidative stress,and inflammatory response in high glucose-induced HK-2 cells via inhibiting the HMGB1/TLR4 signaling pathway.However,the effects induced by TRPM7 silencing were abrogated by HMGB1 overexpression.Conclusions:Decreased TRPM7 alleviates high glucose-induced renal tubular epithelial cell injury by inhibiting the HMGB1/TLR4 signaling pathway.Further animal experiments and clinical trials are warranted to verify its effect.

Inhibition of Ubiquitin-specific Protease 4 Attenuates Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells via Transforming Growth Factor Beta Receptor Type Ⅰ

Objective Ubiquitin-specific protease 4(USP4)facilitates the development of transforming growth factor-beta 1(TGF-β1)-induced epithelial-mesenchymal transition(EMT)in various cancer cells.Moreover,EMT of renal tubular epithelial cells(RTECs)is required for the progression of renal interstitial fibrosis.However,the role of USP4 in EMT of RTECs remains unknown.The present study aimed to explore the effect of USP4 on the EMT of RTECs as well as the involved mechanism.Methods In established unilateral ureteral obstruction(UUO)rats and NRK-52E cells,immunohistochemistry and Western blot assays were performed.Results USP4 expression was increased significantly with obstruction time.In NRK-52E cells stimulated by TGF-β1,USP4 expression was increased in a time-dependent manner.In addition,USP4 silencing with specific siRNA indicated that USP4 protein was suppressed effectively.Meanwhile,USP4 siRNA treatment restored E-cadherin and weakened alpha smooth muscle actin(α-SMA)expression,indicating that USP4 may promote EMT.After treatment with USP4 siRNA and TGF-β1 for 24 h,the expression of TGF-β1 receptor type I(TβRI)was decreased.Conclusion USP4 promotes the EMT of RTECs through upregulating TβRI,thereby facilitating renal interstitial fibrosis.These findings may provide a potential target of USP4 in the treatment of renal fibrosis.

Experimental Study on Detached Renal Tubular Epithelial Cells in Urine of Nephropathia Epidemic Patients

To elucidate the pathogenesis of acute renal failure (ARF) with nephropathia epidemic (NE), provide experimental evidence for the new therapy to NE and observe the effects of Arg-Gly-Asp (RGD) peptides on adhesion of re-nal tubular epithelial cell (RTEC), urine specimens of patients were collected un-der sterile conditions. Detached RTECs were separated, cultured and identified.Hantan Virus antigen was determined by using indirect immunofluorescence method and effects of RGD on adhesion of RTECs was observed by subgroup counting as well as by flow cytometry. This study showed that: (1) sublethal RTECs existed in the urine of NE-ARF patients, which could be cultured in monolayer form; (2 ) there was NE antigen in RTECs; and (3) adhesion of RTECs could be inhibited by RGD.

Comparative proteomic analysis of renal tubular epithelial cell injury caused by oxalic acid and calcium oxalate monohydrate

Objective To analyze and identify the differentially expressed proteins in human renal tubular epithelial ceils ( HK-2) after injury caused by oxalic acid and calcium oxalate monohydrate ( COM ) crystal,and to explore the potential role of renal tubular cell injury in kidney stone formation. Methods Normal HK-2 cells

Effect and mechanism of adrenomedullin on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury

Objective To investigate the effect and mechanism of adrenomedullin ( AM ) on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury. Methods Thirty-two Wistar rats were randomly divided into 4 groups: control group,IRI group, empty plasmid group and AM group. One week after re-

Role of microRNA-181a in the apoptosis of tubular epithelial cell induced by cisplatin

Background Cisplatin （DDP） is one of most effective and most commonly used therapeutic agent in treating tumors,it can accumulate in the kidney and lead to acute renal failure.MicroRNA-181a can induce cell apoptosis by suppressing the expression of Bcl-2 family.In the present study,we investigated the role of microRNA-181a in the apoptosis of tubular epithelial cell induced by DDP.Methods HK-2 cells were cultured,transfected with microRNA-181a inhibitor for 48 hours,and stimulated with 50 μmol/L cisplatin for 24 hours.MicroRNA-181a expression was analyzed by real time PCR,and cell apoptosis was detected by flow cytometry.Moreover,Bcl-2 and Bcl-2-associated X protein （Bax） expression were measured by Western blotting.Results MicroRNA-181a expression significantly down-regulated in cells transfected with microRNA-181a inhibitor,compared with that in untransfectd cells （21.19±2.01 vs.38.87±1.97,P 〈0.05）.Cell apoptosis induced by DDP significantly decreased in cells transfected with MicroRNA-181a inhibitor.Compared with DDP treated cells alone,Bcl-2 expression strikingly was up-regulated and Bax expression was down-regulated in cells transfected with microRNA-181a inhibitor.Conclusion One pathway of DDP induces apoptosis of tubular epithelial cell by suppressing Bcl-2 expression is achieved by regulating the target gene of MicroRNA-181a.

Vitamin C Attenuates Hemorrhagic Shock-induced Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Nonintegrin Expression in Tubular Epithelial Cells and Renal Injury in Rats

Background： The expression of dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin （DC-SIGN） in renal tubular epithelial cells has been thought to be highly correlated with the occurrence of several kidney diseases, but whether it takes place in renal tissues during hemorrhagic shock （HS） is unknown. The present study airned to investigate this phenomenon and the inhibitory effect of Vitamin C （VitC）. Methods： A Sprague Dawley rat HS model was established in vivo in this study. The expression level and location of DC-SIGN were observed in kidneys. Also, the degree of histological damage, the concentrations of tumor necrosis factor-or and interleukin-6 in the renal tissues, and the serum concentration of blood urea nitrogen and creatinine at different times （2-24 h） alter HS （six rats in each group）, with or without VitC treatment belbre resuscitation, were evaluated. Results： HS induced DC-SIGN expression in rat tubular epithelial cells. The proinflarnmatory cytokine concentration, histological damage scores, and functional injury of kidneys had increased. All these phenornena induced by HS were relieved when the rats were treated with VitC before resuscitation. Conclusions： The results of the present study illustrated that HS could induce tubular epithelial cells expressing DC-SIGN, and the levels of proinflarnmatory cytokines in the kidney tissues improved correspondingly. The results also indicated that VitC could suppress the DC-SIGN expression in the tubular epithelial cells induced by HS and alleviate the inflammation and functional injury in the kidney.

Chronic hepatitis B serum promotes apoptotic damage in human renal tubular cells

AIM： To investigate the effect of the serum of patients with chronic hepatitis B （CHB） on apoptosis of renal tubular epithelial cells in vitro and to study the role of hepatitis B virus （HBV） and transforming growth factor-β1 （TGF-β1） in the pathogenesis of hepatitis B virus associated glomerulonephritis （HBV-GN）. METHODS： The levels of serum TGF-β1 were measured by specific enzyme linked immunosorbent assay （ELISA） and HBV DNA was tested by polymerase chain reaction （PCR） in 44 patients with CHB ,and 20 healthy persons as the control. The normal human kidney proximal tubular cell （HK-2） was cultured together with the sera of healthy persons, CHB patients with HBV-DNA negative（20 cases） and HBV-DNA positive （24 cases） for up to 72 h. Apoptosis and Fas expression of the HK-2 were detected by flow cytometer. RESULTS： The apoptosis rate and Fas expression of HK-2 cells were significantly higher in HBV DNA positive serum group 19.01±5.85% and 17.58±8.35%, HBV DNA negative serum group 8.12±2.80% and 6.96 ± 2.76% than those in control group 4.25±0.65% and 2.33 ± 1.09%, respectively （P 〈 0.01）. The apoptosis rate and Fas expression of HK-2 in HBV DNA positive serum group was significantly higher than those in HBV DNA negative serum （P 〈 0.01）. Apoptosis rate of HK-2 cells in HBV DNA positive serum group was positively correlated with the level of HBV-DNA （r = 0.657）. The level of serum TGF-β1 in CHB group was 163.05 ± 91.35 μg/L, signifi- cantly higher as compared with 81.40 ± 40.75 μg/L in the control group （P 〈 0.01）.CONCLUSION： The serum of patients with chronic hepatitis B promotes apoptotic damage in human renal tubular cells by triggering a pathway of Fas up-regulation. HBV and TGF-β1 may play important roles in the mechanism of hepatitis B virus associated glomerulonephritis.

Restoration of E-cadherin by compound 8J protects against cisplatin-induced acute kidney injury by attenuating inflammation and programmed cell death

OBJECTIVE E-cadherin is a major component of tubular adherent proteins which maintain intercellular contacts and cell polarity in epithelial tissue,it is involved in the pathological process of renal cell carcinoma and fibrotic diseases via epithelial-mesenchymal transition.Although we and others found that expression of E-cadherin was significantly down-regulated in kidney suffered acute kidney injury(AKI),its function in AKI was still unknown,which was explored in the current study.METHODS We disrupted E-cadherin or restored E-cadherin with compound 8J in cisplatin-stimulated tubular epithelial cell lines,the cell damage and inflammation were evaluated,additionally,the therapeutic potential of E-cadherin restoration was also determined in vivo.RESULTS We found that cisplatin reduced E-cadherin expression both in mouse kidney and tubular epithelial cell lines(m TECs).Administration of compound 8J restored the level of E-cadherin,thereby increased cell viability while attenuating programmed cell death,which may be mediated by deactivation of RIPK/MLKL axis,reduced membrane translocation of phosphor-MLKL and decreased cleavage of caspase 3.Compound 8J also suppressed inflammatory response in cisplatin-treated m TECs,which was correlated with suppressed NF-κB phorsphorylation and promoter activity.In contrast,disruption of E-cadherin enhanced cell damage and inflammation.Treatment of compound 8J failed to further attenuate kidney damage in E-cadherin knockdown cells,indicating compound 8J protected against mT ECs mainly through restoring E-cadherin.We also found that peritoneal injection of compound 8J protected against renal function and tubular damage by preventing NF-κB-driven renal inflammation and RIPK/MLKL-regulated programmed cell death,which was led by restoration of E-cadherin in cisplatin nephropathy.CONCLUSION More than a victim degraded after kidney injury,E-cadherin also has functional role in controlling tubule integrity,programmed cel death and renal inflammation.In this regard,restoration of E-cadherin by compound 8J should be considered as a novel therapeutic strategy for acute kidney injury.

MicroRNA-630 alleviates inflammatory reactions in rats with diabetic kidney disease by targeting toll-like receptor 4

BACKGROUND Diabetic kidney disease(DKD)is a major complication of diabetes mellitus.Renal tubular epithelial cell(TEC)damage,which is strongly associated with the inflammatory response and mesenchymal trans-differentiation,plays a significant role in DKD;However,the precise molecular mechanism is unknown.The recently identified microRNA-630(miR-630)has been hypothesized to be closely associated with cell migration,apoptosis,and autophagy.However,the association between miR-630 and DKD and the underlying mechanism remain unknown.AIM To investigate how miR-630 affects TEC injury and the inflammatory response in DKD rats.METHODS Streptozotocin was administered to six-week-old male rats to create a hypergly cemic diabetic model.In the second week of modeling,the rats were divided into control,DKD,negative control of lentivirus,and miR-630 overexpression groups.After 8 wk,urine and blood samples were collected for the kidney injury assays,and renal tissues were removed for further molecular assays.The target gene for miR-630 was predicted using bioinformatics,and the association between miR-630 and toll-like receptor 4(TLR4)was confirmed using in vitro investigations and double luciferase reporter gene assays.Overexpression of miR-630 in DKD rats led to changes in body weight,renal weight index,basic blood parameters and histopathological changes.RESULTS The expression level of miR-630 was reduced in the kidney tissue of rats with DKD(P<0.05).The miR-630 and TLR4 expressions in rat renal TECs(NRK-52E)were measured using quantitative reverse transcription polymerase chain reaction.The mRNA expression level of miR-630 was significantly lower in the high-glucose(HG)and HG+mimic negative control(NC)groups than in the normal glucose(NG)group(P<0.05).In contrast,the mRNA expression level of TLR4 was significantly higher in these groups(P<0.05).However,miR-630 mRNA expression increased and TLR4 mRNA expression significantly decreased in the HG+miR-630 mimic group than in the HG+mimic NC group(P<0.05).Furthermore,the levels of tumor necrosis factor-alpha(TNF-α),interleukin-1β(IL-1β),and IL-6 were significantly higher in the HG and HG+mimic NC groups than in NG group(P<0.05).However,the levels of these cytokines were significantly lower in the HG+miR-630 mimic group than in the HG+mimic NC group(P<0.05).Notably,changes in protein expression were observed.The HG and HG+mimic NC groups showed a significant decrease in E-cadherin protein expression,whereas TLR4,α-smooth muscle actin(SMA),and collagen IV protein expression increased(P<0.05).Conversely,the HG+miR-630 mimic group exhibited a significant increase in E-cadherin protein expression and a notable decrease in TLR4,α-SMA,and collagen IV protein expression than in the HG+mimic NC group(P<0.05).The miR-630 targets TLR4 gene expression.In vivo experiments demonstrated that DKD rats treated with miR-630 agomir exhibited significantly higher miR-630 mRNA expression than DKD rats injected with agomir NC.Additionally,rats treated with miR-630 agomir showed significant reductions in urinary albumin,blood glucose,TLR4,and proinflammatory markers(TNF-α,IL-1β,and IL-6)expression levels(P<0.05).Moreover,these rats exhibited fewer kidney lesions and reduced infiltration of inflammatory cells.CONCLUSION MiR-630 may inhibit the inflammatory reaction of DKD by targeting TLR4,and has a protective effect on DKD.

TRPC6 Knockout Alleviates Renal Fibrosis through PI3K/AKT/GSK3B Pathway

Objective Renal fibrosis is the ultimate pathway of various forms of acute and chronic kidney damage.Notably,the knockout of transient receptor potential channel 6(TRPC6)has shown promise in alleviating renal fibrosis.However,the regulatory impact of TRPC6 on renal fibrosis remains unclear.Methods In vivo,TRPC6 knockout(TRPC6−/−)mice and age-matched 129 SvEv(WT)mice underwent unilateral renal ischemia-reperfusion(uIR)injury surgery on the left renal pedicle or sham operation.Kidneys and serum were collected on days 7,14,21,and 28 after euthanasia.In vitro,primary tubular epithelial cells(PTECs)were isolated from TRPC6−/−and WT mice,followed by treatment with transforming growth factorβ1(TGFβ1)for 72 h.The anti-fibrotic effect of TRPC6−/−and the underlying mechanisms were assessed through hematoxylin-eosin staining,Masson staining,immunostaining,qRT-PCR,and Western blotting.Results Increased TRPC6 expression was observed in uIR mice and PTECs treated with TGFβ1.TRPC6−/−alleviated renal fibrosis by reducing the expression of fibrotic markers(Col-1,α-SMA,and vimentin),as well as decreasing the apoptosis and inflammation of PTECs during fibrotic progression both in vivo and in vitro.Additionally,we found that the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/glycogen synthase kinase 3 beta(GSK3β)signaling pathway,a pivotal player in renal fibrosis,was down-regulated following TRPC6 deletion.Conclusion These results suggest that the ablation of TRPC6 may mitigate renal fibrosis by inhibiting the apoptosis and inflammation of PTECs through down-regulation of the PI3K/AKT/GSK3βpathway.Targeting TRPC6 could be a novel therapeutic strategy for preventing chronic kidney disease.

Role of connective growth factor in plasminogen activator inhibitor-1 and fibronectin expression induced by transforming growth factor β1 in renal tubular cells

Background Connective tissue growth factor (CTGF) contributes greatly to renal tubulointerstitial fibrosis, which is the final event leading to end-stage renal failure. This study was designed to investigate the effects of CTGF antisense oligodeoxynucleotides (ODNs) on the expressions of plasminogen activator inhibitor-1 (PAI-1) and fibronectin in renal tubular cells induced by transforming growth factor β1 (TGF-β1) in addition to the role of CTGF in the accumulation and degradation of renal extracellular matrix (ECM).Methods A human proximal tubular epithelial cell line (HKC) was cultured in vitro. Cationic lipid-mediated CTGF antisense ODNs were transfected into HKC cells. After HKC cells were stimulated with TGF-β1 (5 μg/L), the mRNA levels of PAI-1 and fibronectin were measured by RT-PCR. Intracellular PAI-1 protein synthesis was assessed by flow cytometry. The secreted PAI-1 and fibronectin in the medium were determined by Western blot and ELISA, respectively.Results TGF-β1 was found to induce tubular CTGF, PAI-1, and fibronectin mRNA expression. PAI-1 and fibronectin mRNA expression induced by TGF-β1 was significantly inhibited by CTGF antisense ODNs. CTGF antisense ODNs also inhibited intracellular PAI-1 protein synthesis and lowered the levels of PAI-1 and fibronectin protein secreted into the medium.Conclusions CTGF may play a crucial role in the accumulation and degradation of excessive ECM during tubulointerstitial fibrosis, and transfecting CTGF antisense ODNs may be an effective way to prevent renal fibrosis.

Long noncoding RNA X-inactive specific transcript regulates NLR family pyrin domain containing 3/caspase-1-mediated pyroptosis in diabetic nephropathy

BACKGROUND NLRP3-mediated pyroptosis is recognized as an essential modulator of renal disease pathology.Long noncoding RNAs(lncRNAs)are active participators of diabetic nephropathy(DN).X inactive specific transcript(XIST)expression has been reported to be elevated in the serum of DN patients.AIM To evaluate the mechanism of lncRNA XIST in renal tubular epithelial cell(RTEC)pyroptosis in DN.METHODS A DN rat model was established through streptozotocin injection,and XIST was knocked down by tail vein injection of the lentivirus LV sh-XIST.Renal metabolic and biochemical indices were detected,and pathological changes in the renal tissue were assessed.The expression of indicators related to inflammation and pyroptosis was also detected.High glucose(HG)was used to treat HK2 cells,and cell viability and lactate dehydrogenase(LDH)activity were detected after silencing XIST.The subcellular localization and downstream mechanism of XIST were investigated.Finally,a rescue experiment was carried out to verify that XIST regulates NLR family pyrin domain containing 3(NLRP3)/caspase-1-mediated RTEC pyroptosis through the microRNA-15-5p(miR-15b-5p)/Toll-like receptor 4(TLR4)axis.RESULTS XIST was highly expressed in the DN models.XIST silencing improved renal metabolism and biochemical indices and mitigated renal injury.The expression of inflammation and pyroptosis indicators was significantly increased in DN rats and HG-treated HK2 cells;cell viability was decreased and LDH activity was increased after HGtreatment. Silencing XIST inhibited RTEC pyroptosis by inhibiting NLRP3/caspase-1. Mechanistically,XIST sponged miR-15b-5p to regulate TLR4. Silencing XIST inhibited TLR4 by promotingmiR-15b-5p. miR-15b-5p inhibition or TLR4 overexpression averted the inhibitory effect ofsilencing XIST on HG-induced RTEC pyroptosis.CONCLUSIONSilencing XIST inhibits TLR4 by upregulating miR-15b-5p and ultimately inhibits renal injury inDN by inhibiting NLRP3/caspase-1-mediated RTEC pyroptosis.

Anthrahydroquinone-2,6-disulfonate alleviates paraquat-induced kidney injury via the apelin-APJ pathway in rats

Objective:To explore the protective effects of anthrahydroquinone-2,6-disulfonate(AH_(2)QDS)on the kidneys of paraquat(PQ)poisoned rats via the apelin-APJ pathway.Methods:Male Sprague Dawley rats were divided into four experimental groups:control,PQ,PQ+sivelestat,and PQ+AH_(2)QDS.The PQ+sivelestat group served as the positive control group.The model of poisoning was established via intragastric treatment with a 20%PQ pesticide solution at 200 mg/kg.Two hours after poisoning,the PQ+sivelestat group was treated with sivelestat,while the PQ+AH_(2)QDS group was given AH_(2)QDS.Six rats were selected from each group on the first,third,and seventh days after poisoning and dissected after anesthesia.The PQ content of the kidneys was measured using the sodium disulfite method.Hematoxylin-eosin staining of renal tissues was performed to detect pathological changes.Apelin expression in the renal tissues was detected using immunofluorescence.Western blotting was used to detect the expression levels of the following proteins in the kidney tissues:IL-6,TNF-α,apelin-APJ(the apelin-angiotensin receptor),NF-κB p65,caspase-1,caspase-8,glucose-regulated protein 78(GRP78),and the C/EBP homologous protein(CHOP).In in vitro study,a PQ toxicity model was established using human tubular epithelial cells treated with standard PQ.Twenty-four hours after poisoning,sivelestat and AH_(2)QDS were administered.The levels of oxidative stress in human renal tubular epithelial cells were assessed using a reactive oxygen species fluorescence probe.Results:The PQ content in the kidney tissues of the PQ group was higher than that of the PQ+AH_(2)QDS group.Hematoxylin-eosin staining showed extensive hemorrhage and congestion in the renal parenchyma of the PQ group.Vacuolar degeneration of the renal tubule epithelial cells,deposition of crescent-like red staining material in renal follicles,infiltration by a few inflammatory cells,and a small number of cast formation were also observed.However,these pathological changes were less severe in the PQ+sivelestat group and the PQ+AH_(2)QDS group(P<0.05).On the third day after poisoning,immunofluorescence assay showed that the level of apelin in the renal tissues was significantly higher in the PQ+AH_(2)QDS group than in the PQ group.Western blotting analysis results showed that IL-6,TNF-α,NF-κB p65,caspase-1,caspase-8,GRP78,and CHOP protein levels in the PQ group were higher than in the PQ+AH_(2)QDS group(P<0.05).The expression of apelin-APJ proteins in the PQ+AH_(2)QDS group was higher than in the PQ+sivelestat and PQ groups(P<0.05);this difference was significant on Day 3 and Day 7.The level of oxidative stress in the renal tubular epithelial cells of the PQ+AH_(2)QDS group and the PQ+sivelestat group was significantly lower than in the PQ group(P<0.05).Conclusions:This study confirms that AH_(2)QDS has a protective effect on PQ-poisoned kidneys and its positive effect is superior to that of sivelestat.The mechanism of the protective effects of AH_(2)QDS may be linked to reduction in cellular oxidative stress,PQ content of renal tissue,inflammatory injury,endoplasmic reticulum stress,and apoptosis.AH_(2)QDS may play a role in the treatment of PQ poisoning by upregulating the expression of the apelin-APJ.

Construction of Bioartificial Renal Tubule Assist Device In Vitro and Its Function of Transporting Sodium and Glucose

To explore a new way of constructing bioartificial renal tubule assist device （RAD） in vitro and its function of transporting sodium （Na^＋） and glucose and to evaluate the application of atomic force microscope in the RAD construction, rat renal tubular epithelial cell line NRK-52E was cultured in vitro, seeded onto the outer surfaces of hollow fibers in a bioreactor, and then cultured for two weeks to construct RAD. Bioreactor hollow fibers without NRK-52E cells were used as control. The morphologies of attached cells were observed with scanning electron microscope, and the junctions of cells and polysulfone membrane were observed with atomic force microscope. Transportation of Na＋ and glucose was measured. Oubaine and phlorizin were used to inhibit the transporting property. The results showed that NRK-52E cells and polysulfone membrane were closely linked, as observed under atomic force microscope. After exposure to oubaine and phlorizin, transporting rates of Na^＋ and glucose were decreased significantly in the RAD group as compared with that in the control group （P〈0.01）. Furthermore, when the inhibitors were removed, transportation of Na^＋ and glucose was restored. It is concluded that a new RAD was constructed successfully in vitro, and it is able to selectively transport Na^＋ and glucose.

Tumor suppressor cylindromatosis： expressed in IgA nephropathy and negatively associated with renal tubulo-interstitial lesion

Background IgA nephropathy is the major cause of end-stage renal failure in patients with primary glomerular diseases. Tumor suppressor cylindromatosis （CYLD）, the recently identified member of the deubiquitinating enzymes, has been actively involved in regulation of inflammation. This study was undertaken to investigate the CYLD expression profile in IgA nephropathy and identify factors associated with CYLD expression. Methods Forty-one cases of IgA nephropathy were selected. CYLD expression in the kidney biopsy tissue was measured by immunohistochemical staining. Relevant clinical and pathological data were analyzed, and Logistic regression analysis was carried out to identify factors associated with CYLD expression. Results CYLD was specifically expressed in renal tubular epithelial cells in 70% of the studied patients with IgA nephropathy. All patients with positive CYLD staining had proteinuria, while only 72.7% of patients with negative CYLD had proteinuria （P=0.003）. Among studied proteinuric patients, those with positive CYLD had significantly less tubulo-interstitial lesions and higher estimated glomerular filtration rate （eGFR） levels when compared with those patients showed negative CYLD results. Logistic regression analysis indicated that the urinary protein excretion and eGFR were identified as predictors for the CYLD expression. Conclusion CYLD is expressed in renal tubular epithelial cells and appears to be associated negatively with tubulointerstitial lesions, however, its exact functional role remains to be clarified in further experiments.