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Objective To explore the influence of fenofibrate on apoptosis of human renal proximal tubular cells(HK?2)induced by free fatty acid (FFAs). Methods Methyl azo thiazole blue(determined by MTT)was applied for detection of HK?2 cell proliferation capacity;Spectrophotometry was used to determine the expression of MDA and SOD;MCP?1 and IL?8 in culture supernatant of cells were detected by ELISA;Real?time PCR and Western blot were used to evaluate mRNA and protein expression of Bax and Bcl?2 respectively. Results FFAs inhibited HK?2 cell prolifera?tion in a dose and time dependence. mRNA and protein expression of Bax significantly increased compared with control,but mRNA and protein ex?pression of Bcl?2 decreased. After preincubation of fenofibrate,the inhibition of HK?2 cell proliferation by FFAs was alleviated;expression of SOD increased and expression of MDA,MCP?1 and IL?8 were decreased;mRNA and protein expression of Bax was significantly decreased,but mRNA and protein expression of Bcl?2 was increased. Conclusion FFAs can induce apoptosis of renal proximal tubular cell in a dose and time dependent manner. Fenofibrate can inhibite HK?2 cell apoptosis by decreasing oxidative stress,inhibiting inflammation,up?regulating expression of Bcl?2 and down?regulating expression of Bax,which alleviated nephrotoxicity of FFAs.
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Objective To study the molecular mechanism of renal injury of chronic arsenic poisoning rats induced by the expression of cysteine caspase-8 and P53 in renal proximal tubular epithelial cells.Methods Sixty healthy SD rats were divided into three groups,high-,low-dose group,and control group,n =20 in each group.The rats in high and low dose groups were treated with As203 through drinking water,10.0 and 0.4 mg/kg,respectively.The control rats were given distilled water.Four months later,serum and urinary arsenic level was determined,and kidney specimens were taken.The expression of cysteine caspase-8 and P53 in renal proximal tubular epithelial cells was detected by histological technique-HE staining and SABC immunohistochemistry.In addition,cell number counting and image analyses were used in the study.Results The number of caspase-8 positive cells of renal proximal tubule in control group,low-and high-dose group was 3.33±1.32,31.14±8.02 and 46.50±7.20 cell number/visual fields,respectively,which was increased with dose increasing(all P ＜0.05);the average gray value was 151.34±6.40,133.58±4.63 and 128.34±16.28,respectively,decreased with dose increasing(all P ＜0.05).The number of P53 positive cells was 3.17±1.59,26.29±4.23 and 47.00±6.22 cell number/visual fields,respectively,increased with dose increasing (all P ＜ 0.05) ; the average gray value was 142.54±8.06,121.48±5.68 and 101.89±6.35,respectively,decreased with dose increasing (all P ＜ 0.05).Conclusion The increase of caspase-8 and P53 positive cells is one of the molecular mechanisms of renal injury induced by arsenic poisoning.
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Aim To investigate the time-dependent effect of insulin on the expression of SREBP-1(sterol regulatory element binding protein-1),FAS(fat acid synthase)and lipid droplet formation in HKC cells(human renal proximal tubular epithelial cells line).MethodsHKC cells were respectively treated with 100 nmol·L~(-1) insulin for 0,2,4,6,12 h and 24 h.The analysis of SREBP-1 and FAS mRNA was performed by RT-PCR and the expression of SREBP-1 protein was detected by Western blot and immunocytochemistry.Furthermore,Oil Red O staining was used to determine cellular lipid droplet formation.ResultsCompared with HKC cells of 0 h group,there was no difference of SREBP-1 and FAS mRNA in HKC cells of 2 h group.However,the expression of SREBP-1 and FAS mRNA was significantly increased in HKC cells of 4,6 h and 12 h group.Further,the most expression of SREBP-1 and FAS mRNA was at 6 h group and was respectively increased by 3.578 and 4.272 times compared with 0 h group.The results of Western blot showed that the precursor and mature segments of SREBP-1 protein in 4,6 h and 12 h group HKC cells were increased and those of 6 h group HKC cells were the highest and about 4.106 and 5.167 times than those of 0 h group HKC cells.Immunocytochemistry presented the result that SREBP-1 protein was located in the plasma and the expression of 4,6 h and 12 h group HKC cells was significantly higher than that of 0,2 h and 24 h group HKC cells.The result of Oil Red O staining showed that lipid droplet markedly deposited in 6 h group HKC cells,contrarily,no lipid droplet was found in HKC cells of other groups.ConclusionAbove results suggested that insulin up-regulated SREBP-1 and FAS in time-dependent manner that led to cellular lipid droplet deposit,which may play an important role in the pathogenesis of renal lipid accumulation in metabolism syndrome.
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BACKGROUND: Toll like receptor (TLR), an element of innate immunity, is upregulated by Ischemia/reperfusion (IR) injury and may be involved in adaptive immune response. Immunosuppressive agents may increase or attenuate IR injury and TLR expression. To explore the involvement of TLRs in hypoxic tubular injury and modification by mycophenolic acid (MPA) rapamycin (RAP), this study examined TLR expression in hypoxia-induced human renal proximal tubular epithelial cells (HK-2). METHODS: HK-2 cells were cultured in keratinocyte-SFM media supplemented with epidermal growth factor and bovine pituitary extract. The Induction of hypoxia was achieved using GasPak pouch system. TLR 2, 3, and 4 mRNA expression was analyzed by real time RT-PCR using SYBR green and TLR 4 protein expression was evaluated by Western blot analysis. MPA at concentration of 100 nM and 1uM and RAP at concentration of 20, 50, and 100 nM were added to culture medium. RESULTS: TLR4 but noTLR2 or TLR3 mRNA expressions increased in hypoxic HK-2 cells at 24 and 48 hrs. TLR4 protein expression also increased in hypoxic HK-2 cells at 24 and 48 hrs. MPA (100 nM and 1uM) and RAP (20, 50, and 100 nM) decreased hypoxia-induced TLR4 mRNA expression in HK-2 cells compared to normoxia at 24 hrs. However, TLR4 protein expression was decreased only by RAP at 20 and 50 nM. CONCLUSIONS: The results suggest that RAP may modify hypoxic renal tubular damage by decreasing TLR4-mediated inflammatory and immune reactions.
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Humans , Adaptive Immunity , Hypoxia , Blotting, Western , Epidermal Growth Factor , Epithelial Cells , Immunity, Innate , Immunosuppressive Agents , Mycophenolic Acid , RNA, Messenger , Sirolimus , Toll-Like ReceptorsABSTRACT
ObjectiveTo investigate the effects and molecular mechanism of endoplasmic reticalam stress (ERS) on albumin-induced apoptosis in renal proximal tubular cells (HKCs). MethodsWestern blot was performed to detect the relationship of the expression of glucose-regulated protein 78 (GRF78) and CCAAT/enhancer-binding protein-homologous protein (CHOP) with the action time and concentration of haman serum albumin (HSA). Expression levels of CHPO mRNA and protein in HKCs after CHOP siRNA transfection were examined by real-time fluorescence quantitative PCR and Western blot respectively. Annexin-V-FITC and PI doable staining cytometry was used to detect the apoptosis of HKCs induced by HSA and influenced by CHOP siRNA. Results(1)After HKCs were stimulatde by 0, 5, 10, 20 g/L albumin for 24 hours respectively, the expression of GRP78, CHOP and HKCs apoptosis were increased with the albumin concentration (P<0.01). After HKCs were stimulated by 20 g/L albumin for 0, 6, 12, 24, 36 hours respectively, the expression of GRP78 was up-regulated at 6-hour, while CHOP and HKCs apoptosis were increased at 12-hour, and significant differences were found among groups (P<0.01). (2) CHOP siRNA significantly inhibited albumin-induced HKC CHOP mRNA and protein expression, as well as HKC apoptosis (P<0.01). ConclusionsRenal tubular cells exposed to high protein load result in EBS. ERS may subsequently lead to tubular damage by activation of pro-apoptosis factor CHOP.
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0.05). Conclusion The labeling of iTRAQ in HK-2 cells is successful with favourable reproducibi-lity,which lays a foundation for the further research of proteomics in renal diseases.
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Betaig-h3 (betaig-h3) is a secretory protein composed of fasciclin I-like repeats containing sequences that allows binding of integrins and glycosaminoglycans in vivo. Expression of betaig-h3 is responsive to TGF-beta and the protein is found to be associated with extracellular matrix (ECM) molecules, implicating betaig-h3 as an ECM adhesive protein of developmental processes. We previously observed predominant expression of betaig-h3 expression in the basement membrane of proximal tubules of kidney. In this study, the physiological relevance of such localized expression of betaig-h3 was examined in the renal proximal tubular epithelial cells (RPTEC). RPTEC constitutively expressed betaig-h3 and the expression was dramatically induced by exogenous TGF-beta1 treatment. betaig-h3 and its second and fourth FAS1 domain were able to mediate RPTEC adhesion, spreading and migration. Two known alpha3beta1 integrin-interaction motifs including aspartatic acid and isoleucine residues, NKDIL and EPDIM in betaig-h3 were responsible to mediate RPTEC adhesion, spreading, and migration. By using specific antibodies against integrins, we confirmed that alpha3beta1 integrin mediates the adhesion and migration of RPTECs on betaig-h3. In addition, it also enhanced proliferation of RPTECs through NKDIL and EPDIM. These results indicate that betaig-h3 mediates adhesion, spreading, migration and proliferation of RPTECs through the interaction with alpha3beta1 integrin and is intimately involved in the maintenance and the regeneration of renal proximal tubular epithelium.
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Humans , Amino Acid Motifs , Antibodies, Blocking/immunology , Cell Adhesion/physiology , Cell Movement/physiology , Cell Proliferation , Cells, Cultured , Epithelial Cells/drug effects , Extracellular Matrix Proteins/chemistry , Integrin alpha3beta1/chemistry , Kidney Tubules, Proximal/cytology , Peptides/chemistry , Protein Interaction Mapping , Transforming Growth Factor beta/chemistryABSTRACT
AIM: To study the effect of Bene Jones protein (BJP) from multiple myeloma(MM) patient and TGF-? 1 on cultured renal proximal tubular cell(PTC) proliferation. METHODS:[ 3H] TdR incorporation was used to study the effect of ?BJP and TGF-? 1 on cultured rat NRK.52E PTC proliferation,the expression of TGF-? 1 in the supernatant of PTC cultured with BJP was assessed with ELISA. RESULTS:① [ 3H] TdR incorporation of PTC was inhibited by BJP in a dose-dependent manner,when co-cultured with 100-800 ?mol/L BJP and 2.0 ?g/L TGF-? 1, the [ 3H] TdR incorporation was lower than that of BJP alone, especially when BJP≥400 ?mol/L; ②The expression of TGF-? 1 in the supernatant of PTC cultured with BJP was increased ,especially when BJP≥400 ?mol/L( P
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Objective To explore the possible mechanism of nitric oxide(NO) involved in iron-mediated cytotoxicity on renal tubular cells, meanwhile to estimate the effect of reactive oxygen sepcies scavenger on iron-mediated cytotoxicity and its relation to nitric oxide. Methods in this study, the relationship between NO production and lactate dehydrogenase(LDH) release were observed in primary subconfluent proximal tubular cells coincubated with different doses of NTA-Fe and lipopolysaccharide(LPS) alone or in combination. NO production was monitored by NO2 -- concentration in supernatant based on Griess reaction. Meanwhile, semi-quantitative RT-PCR was applied to detect the inducible nitric oxide synthase (iNOS) mRNA level induced by NTA-Fe and LPS together. In addition, experimental groups were exposed to reactive oxygen species (ROS) scavengers to determine the impact of the interaction between NO and ROS on iron-mediated cytotoxicity. Results After 12-hour coincubation, NTA-Fe could increase both LDH release and NO2 production in a dose-dependent manner (P 0. 05 ) although tubular injury was aggravated (P
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Objective To study protective effects of vitamin E(VE) on renal proximal tubular cells of mice treated with cadmium chronically. Methods 75 Kunming mice were divided into 3 groups randomly, cadmium group, VE group, control group. The mice in cadmium group were treated with cadmium in 2 mg/kg by subcutaneously injected, twice per week, in VE group they were treated with VE in 10 mg/(kg?d) additionally, in control group the animals were treated with saline only. 3 months later the finestuctural changes of the renal proximal tubule cells were observed by electron microscopy and immunohistochemistry(Tunel method). The ultrastuctures of nuclei were revealed with stereological analysis. The apoptotic cells were counted with image analysis. Results The structure of the renal proximal tubule cells of mice in the VE group was similar to those in the control group, but it had significant changed compared with those of the cadmium group. Compared with the control group, the nuclear important morphological parameters of VE group increased significantly (P
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Aim To construct eukaryotic expression vector of shRNA(small hairpin RNA)for human SREBP-1(sterol regulation element binding protein-1)gene and explore its effects on lipid droplet formation in human renal proximal tubular epithelial cell line(HKC)under the stimulation of high glucose.Methods Two eukaryotic expression vectors of shRNA were constructed for human SREBP-1 gene.The HKC cells were transfected with negative control plasmid(pGenesil-1-HK)and two recombinant vectors(pGenesil-1-SREBP1-1 and pGenesil-1-SREBP1-2)and then were cultured under the stimulation of high glucose for about 48 h.The expression of SREBP-1 mRNA and FAS mRNA was detected by RT-PCR and SREBP-1 protein expression was investigated by Western blot.Lipid droplets were detected by Oil Red O staining.Results DNA sequencing showed that the target segments were successfully cloned into pGenesil-1 vector respectively.RT-PCR indicated that two recombinant vectors could inhibit the expression of SREBP-1 mRNA and FAS mRNA in HKC cells under the stimulation of high glucose.Similarly,SREBP-1 protein was also inhibited by the transfection with recombinant vectors.Oil Red O staining found that silencing of SREBP-1 gene resulted in lipid droplets decrease.Conclusions The eukaryotic expression vector of shRNA for human SREBP-1 gene was successfully constructed,and the expression of SREBP-1 was inhibited effectively by the expressed siRNA in HKC cells that resulted in lipid droplets decrease through FAS mRNA transcription inhibition.
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Objective To explore expression of hypoxia inducible factor-1?(HIF-1?)in kidney cells during hypoxia/reoxygenation injury,and to study the effect of Danshen on prevention of the hypoxia/reoxygenation injury to cells.Methods Human renal proximal tubular cells(HK-2)were used as the target cell.There were 3 groups:control group,model group,Danshen group.hypoxia/reoxygenation models after neonatal asphyxia were established with liquid paraffin covering method.Expression of HIF-1? were detected with strcp avidin biotin complex(SABC)immunohistochemistry at following different time points:hypoxia 1,4,8,12,24 h,which means 1,4,8,12,24 h respectively after hypoxia;and hypoxia/reoxygenation 1,4,8,12,24 h,which means 1,4,8,12,24 h respectively after hypoxia/reoxygenation.Results HIF-1? was expressed mainly in HK-2's nucleus.There had low expression of HIF-1? in HK-2 cells under the normal culture,and its expression level kept rising quickly during hypoxic/reoxygenatic culture,until 4 h after the beginning of reoxygenation.Compared with the study group,the expression level of HIF-1? in HK-2 cells of the Danshen group were significantly lower at different time points(Pa