The inhibitory effect of calcium dobesilate on cisplatin induced HK-2 cell apoptosis and its mechanism / 药学学报

We observed the effect of calcium dobesilate (CaD) on apoptosis induced by cisplatin in human proximal tubular epithelial cells (HK-2) and explored the possible mechanism. Based on HK-2 cells apoptosis model induced by cisplatin, CCK-8 method was used to detect the effect of CaD on the proliferation of HK-2. Apoptosis was detected by flow cytometry. Reactive oxygen species (ROS) assay was used to evaluate the level of oxidative stress. The mitochondrial membrane potential was measured by JC-1 method. The expression levels of p53, caspase-3, bcl-2 and bax in cisplatin-induced HK-2 were detected by Western blot. The expression of renal injury factor 1(KIM-1) and neutrophil gelatin-related apolipoprotein (NGAL), markers of acute kidney injury, were detected by ELISA. The results showed that CaD could reduce the oxidative stress level induced by cisplatin and inhibit apoptosis in renal tubular epithelial cells. Cisplatin can up-regulate the protein expressions of p53, caspase-3, bax, KIM-1 and NGAL, and reduce the expression of bcl-2. After using CaD, the protein levels of KIM-1, NGAL, p53, caspase-3 and bax were significantly reduced, while the levels of bcl-2 were increased. This study has shown that CaD can alleviate cisplatin-induced HK-2 injury and inhibit HK-2 apoptosis, which may be related to the regulation of bax/bcl-2/caspase-3 apoptosis signaling pathway.

Paricalcitol attenuates indoxyl sulfate-induced apoptosis through the inhibition of MAPK, Akt, and NF-κB activation in HK-2 cells

BACKGROUND/AIMS: Indoxyl sulfate (IS) is a uremic toxin and an important causative factor in the progression of chronic kidney disease. Recently, paricalcitol (19-nor-1,25-dihydroxyvitamin D2) was shown to exhibit protective effects in kidney injury. Here, we investigated the effects of paricalcitol treatment on IS-induced renal tubular injury. METHODS: The fluorescent dye 2ʹ,7ʹ-dichlorofluorescein diacetate was used to measure intracellular reactive oxygen species (ROS) following IS administration in human renal proximal tubular epithelial (HK-2) cells. The effects of IS on cell viability were determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays and levels of apoptosis-related proteins (Bcl-2-associated protein X [Bax] and B-cell lymphoma 2 [Bcl-2]), nuclear factor-κB (NF-κB) p65, and phosphorylation of mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) were determined by semiquantitative immunoblotting. The promoter activity of NF-κB was measured by luciferase assays and apoptosis was determined by f low cytometry of cells stained with f luorescein isothiocyanate-conjugated Annexin V protein. RESULTS: IS treatment increased ROS production, decreased cell viability and induced apoptosis in HK-2 cells. IS treatment increased the expression of apoptosis-related protein Bax, decreased Bcl-2 expression, and activated phosphorylation of MAPK, NF-κB p65, and Akt. In contrast, paricalcitol treatment decreased Bax expression, increased Bcl-2 expression, and inhibited phosphorylation of MAPK, NF-κB p65, and Akt in HK-2 cells. NF-κB promoter activity was increased following IS, administration and was counteracted by pretreatment with paricalcitol. Additionally, flow cytometry analysis revealed that IS-induced apoptosis was attenuated by paricalcitol treatment, which resulted in decreased numbers of fluorescein isothiocyanate-conjugated Annexin V positive cells. CONCLUSIONS: Treatment with paricalcitol inhibited IS-induced apoptosis by regulating MAPK, NF-κB, and Akt signaling pathway in HK-2 cells.

Application of isobaric tags labeling in proteomic research of human renal proximal tubular epithelial cells / 上海第二医科大学学报

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.

Beta ig-h3 promotes renal proximal tubular epithelial cell adhesion, migration and proliferation through the interaction with alpha3beta1 integrin

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.

Human kidney proximal tubular epithelial cell line expresses paxillin induced by TGF-?_1 / 第三军医大学学报

Objective To investigate the expression of Paxillin (Pax) in human kidney proximal tubular epithelial cell line (HKC) induced by transforming growth factor ?1(TGF?1). Methods HKC cells cultured in vitro were divided into three groups at random: control group(C): cultured with free serum medium(FSM), TGF?1-treated groups (T1 and T2): cultured with FSM containing different concentrations of TGF?1 (T1: 5 ng/ml, T2: 10 ng/ml). After 48-hour treatment, the expression of Pax mRNA and protein was detected by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical staining in HKC cells respectively. Results In Group C, the expression of Pax mRNA and protein in HKC cells was elementary. However, in T1 and T2 groups , the expression of Pax mRNA and protein in HKC cells was greatly increased, especially in T2 group which was more significantly increased than T1 group (P

Effect of high glucose on the expression of Toll-like receptor 4 and the signal pathway in renal tubular epithelial cells / 重庆医科大学学报

Objective:To explore the role of Toll-likereceptor 4 in the production of inflammatory factors in renal innate cells stimulated with high glucose by studying the effect of high glucose on the expression of TLR4 and its signal pathway. Methods:Western Blot analysis was taken to measure the expression of TLR4,and the combination of Western Blot and immunoprecipitation was used to analyze the correlation of TLR4 with MyD88. Results:High glucose upregulated the expression of TLR4 protein and activated MyD88-dependent pathyway in MCT cells. Conclusion:TLR4 is involved in the pathogenesis of diabetic nephropathy by playing a role in the production of inflammatory factors in renal innate cells stimulated with high glucose.

Effects of SREBP-1 targeted RNAi on lipid droplet formation in HKC cells under stimulation of high glucose / 中国药理学通报

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.

Effect of activated PI3-K on epithelial-mesenchymal trans-differentiation of HK cells induced by TGF-?_1 in vitro / 解放军医学杂志

Objective To investigate the effect of activated PI3-K on epithelial-mesenchymal transdifferentiation of HKCs induced by transforming growth factor?1 (TGF-?1). Methods The human kidney proximal tubular epithelial cells (HKCs) cultured on plastic plates were divided into following groups: cultured with free serum medium (FSM); culture in the different concentrations of TGF-?1; cultured in the presence of recombinant human TGF-?1 and PI3-K inhibitor Wortmannin. The expression of total and phosphor-Akt (t-Akt and p-Akt) was assessed at different time points by Western blot,? smooth muscle actin(?-SMA) and E-cadherin were detected by Western blot. Results A marked increase in p-Akt was seen in HKC at 1h after being induced by TGF-?1, and its protein level was enhanced in a TGF-?1 concentration-dependent manner. Protein level of ?-SMA was increased markedly at 48 hours after the treatment of TGF-?1, but protein level of E-cadherin was decreased 48 hours after treatment of TGF-?1. Addition of PI3-K inhibitor Wortmannin (10nmol/L) largely abrogated the effect of TGF-?1. Wortmannin was showed to down-regulate ?-SMA and p-Akt expression and in response to TGF-?1 and up-regulate E-cadherin expression. Conclusion PI3-K was activated in epithelial-mesenchymal trans-differentiation of HKCs promoted by TGF-?1, and PI3-K inhibitor Wortmannin can significantly inhibit TGF-?1 induction of EMT.