OBJECTIVETo observe the effect of bone morphogenetic protein-7 (BMP-7) on aristolchic acid induced renal tubular epithelial cell trans-differentiation to look for new therapeutic approach for aristolchic acid nephropathy (AAN).

METHODSIn vitro cultured human proximal renal tubular epithelial cell line HK-2 cells were treated with different concentrations of BMP-7 (75 ng/mL, 150 ng/mL and 300 ng/mL) after trans-differentiation of the cells was induced by AA (10 microg/mL). Levels of alpha-SMA mRNA and protein expressions were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting respectively.

RESULTSBMP-7 reversed the AA inducing alpha-SMA expressions in HK-2 cells in a dose-dependent manner.

CONCLUSIONBMP-7 can inhibit the trans-differentiation of human renal tubular epithelial cell induced by AA, thereby might be a new potential drug for AAN prevention and treatment.

Actins ; metabolism ; Aristolochic Acids ; adverse effects ; Bone Morphogenetic Protein 7 ; pharmacology ; Cell Line ; Cell Transdifferentiation ; drug effects ; Epithelial Cells ; cytology ; Humans ; Kidney Tubules, Proximal ; cytology

OBJECTIVETo study whether aristololactam I (AL-I) can enter renal proximal tubular epithelial cells and the situation of intracellular distribution and accumulation.

METHODCultured human renal proximal tubular epithelial cell line (HK-2) was used as the subject. Intracellular fluorescence from AL-I and its distribution are examined by fluorescence microscopy after a treatment with different concentration of AL-I, the intracellular accumulation of AL-I was also investigated by incubated cells in AL-I -free medium for 48 h after washing-out the media containing AL-I.

RESULTAfter treatment of AL-I (concentration from 5 microg x mL(-1) to 20 microg x mL(-1)), glaucous fluorescence could be observed inside renal proximal tubular epithelial cells at 0.5 h, and the fluorescence distributed only in cytoplasm while not be observed in nuclei. Moreover, the fluorescence of AL-I could be kept in cytoplasm for more than 48 h after washing out the media containing AL-I .

CONCLUSIONAL-I is able to enter renal proximal tubular epithelial cells in short time and accumulate in cytoplasm, but not enter nuclei. This property may contribute to the cytotoxic mechanism of renal injury induced by AL-I, which may partially explain the persistent renal toxicity of AAs and its metabolites in the development of aristolochic acid nephropathy.

Animals ; Aristolochic Acids ; metabolism ; toxicity ; Cell Line ; Cell Nucleus ; drug effects ; metabolism ; Cytoplasm ; drug effects ; metabolism ; Epithelial Cells ; cytology ; drug effects ; metabolism ; pathology ; Humans ; Kidney Diseases ; metabolism ; pathology ; Kidney Tubules, Proximal ; cytology ; pathology ; Microscopy, Fluorescence

OBJECTIVETo observe the expressions of Wnt/beta-catenin and the effects of tanshinone IIA (TII A) on Wnt/beta-catenin signaling pathway in high glucose induced renal tubular epithelial cell transdifferentiation.

METHODSHuman kidney proximal tubular epithelial cells (HK-2) were divided into three groups, i. e., the normal glucose group, the high glucose group, and the high glucose plus tanshinone IIA group. The expression of beta-catenin was observed using immunocytochemical staining. The protein expression of beta-catenin, E-cadherin, and alpha-smooth muscle actin (alpha-SMA) were detected by Western blot. The mRNA levels of beta-catenin and E-cadherin were detected by RT-PCR.

RESULTSCompared with the normal glucose group, both the protein and the mRNA expressions of beta-catenin were significantly enhanced (P < 0.01), the expression of E-cadherin significantly decreased (P < 0.01), the expression of beta-catenin increased in the cytoplasm and nucleus in the high glucose group. TIIA at the final concentration of 100 micromol/L significantly reduced the ectopic expression of beta-catenin. At that concentration, the protein and mRNA expressions of beta-catenin in the nucleus significantly decreased, while the protein and mRNA expressions of E-cadherin were up-regulated. Meanwhile, the expression of alpha-SMA obviously decreased.

CONCLUSIONSWnt/beta-catenin signaling pathway participated in the high glucose induced renal tubular epithelial cell transdifferentiation. TIIA inhibited the transdifferentiation process possibly through down-regulating the activities of Wnt/beta-catenin signaling pathway, thus further playing a role in renal protection.

Cadherins ; metabolism ; Cell Line ; Cell Transdifferentiation ; drug effects ; Diterpenes, Abietane ; pharmacology ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Glucose ; adverse effects ; Humans ; Kidney Tubules, Proximal ; cytology ; drug effects ; metabolism ; Wnt Signaling Pathway ; drug effects ; beta Catenin ; metabolism

Cell Differentiation ; drug effects ; Cell Line ; Connective Tissue Growth Factor ; metabolism ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Epithelial-Mesenchymal Transition ; drug effects ; Humans ; Kidney Tubules, Proximal ; cytology ; Lead ; toxicity ; Transforming Growth Factor beta ; metabolism

OBJECTIVETo explore the effect of p38MAPK signaling pathway in interleukin-18-induced transdifferentiation in renal proximal tubular cells.

METHODSHuman proximal tubular epithelial cell line (HK-2 cells) was cultured in vitro. After preincubated with SB203580 (0, 5, 10, 20 micromol/L) for 30 minutes, cells were exposed to IL-18 (100 ng/ml) for 24, 48 and 72 hours respectively. The expressions of a-smooth actin (alpha-SMA) in cultured HK-2 cells were assessed by RT-PCR and ELISA.

RESULTSIL-18-induced expressions of a-SMA mRNA and protein were inhibited obviously by a dose-dependent manner when HK-2 cells were incubated with SB203580 (0, 5, 10, 20 micromol/L) and IL-18 (100 ng/ml) for different time (P < 0.05).

CONCLUSIONIL-18-induced transdifferentiation of renal tubular epithelial cells (RTECs) is suppressed obviously by blocking p38MAPK signaling pathways. IL-18-induced transdifferentiation of RTECs is probably mediated, at least in part, through the activation of p38MAPK signaling pathways.

Cell Line ; Cell Transdifferentiation ; drug effects ; Enzyme Inhibitors ; pharmacology ; Epithelial Cells ; cytology ; Fibrosis ; physiopathology ; Humans ; Imidazoles ; pharmacology ; Interleukin-18 ; pharmacology ; Kidney ; pathology ; Kidney Tubules, Proximal ; cytology ; MAP Kinase Signaling System ; Myofibroblasts ; cytology ; Pyridines ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVE: To observe the effect of norcantharidin (NCTD) on the expression of mRNA and protein of fibronectin (FN), collagen IV(Col IV) and transforming growth factor-β1(TGF-β1) in human kidney proximal tubular epithelial (HK)-2 cells induced by high glucose. METHODS: HK-2 cells were incubated with serum-free DMEM for 24 h to synchronize cell growth, and then the cells were divided into 4 groups: Group C (5.5 mmol/L D-glucose), Group M (5.5 mmol/L D-glucose + 24.5 mmol/L-mannitol), Group HG (30 mmol/L D-glucose), and Group HG + NCTD (30 mmol/L D-glucose + 0.5-40 mg/L NCTD). Cytotoxicity of HK-2 cells induced by high glucose of NCTD was detected by Trypan blue dye exclusive assay. The effect of NCTD on the proliferation of HK-2 cells in high glucose was determined by MTT. The cells were collected to extract total RNA and protein at 6, 24 and 48 h after the incubation. The expression of FN, Col IV and TGF-β1 mRNA was examined by RT-PCR, and FN, Col IV and TGF-β1 protein was analyzed by Western blot. RESULTS: Trypan blue dye exclusive assay showed NCTD concentrations over 5 mg/L were rather toxic in HK-2 cells. The proliferation of HK-2 cells in high glucose was interrupted by interfered with 5 mg/L NCTD as measured by MTT (P<0.05). NCTD at 5 mg/L had a stronger inhibitory effect than NCTD at 2.5 mg/L. Real-time PCR and Western blot showed that the mRNA and protein expression of FN, collagen IV and TGF-β1 increased in HK-2 cells treated with high glucose (P<0.05), while that in cells treated by NCTD was dramatically inhibited (P<0.05). No change in these parameters was detected in the 30 mmol/L D-mannitol control group (P>0.05). CONCLUSION NCTD can downregulate FN, collagen IV and TGF-β1 mRNA and protein expression in HK-2 cells stimulated by 30 mmol/L D-glucose.
Bridged Bicyclo Compounds, Heterocyclic ; pharmacology ; Cell Line ; Collagen Type IV ; genetics ; metabolism ; Down-Regulation ; drug effects ; Epithelial Cells ; cytology ; Fibronectins ; genetics ; metabolism ; Glucose ; pharmacology ; Humans ; Kidney Tubules, Proximal ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Transforming Growth Factor beta1 ; genetics ; metabolism

OBJECTIVETo study whether aristololactam I (AL-I) induces injury in human renal proximal tubular epithelial cells.

METHODCultured human renal proximal tubular epithelial cell line HK-2 was used as the subject. Aristolochic Acid I (AA-I) was used as a positive control. Cell toxicity of AL-I was detected by LDH releasing rate. Cell apoptosis was evaluated by cellular morphology, DNA content and expression of cell membrane phosphatidylserine (PS). The secretion level of fibronectin (FN) and TGF-beta1 in HK-2 cells were assayed by ELISA.

RESULTAL-I had a direct toxicity on HK-2 in a dose dependent manner from 2.5 mg x mL(-1) to 20 mg x mL(-1); In these range of concentration, AL-I could induce cell apoptosis which was detectable by measurements of morphology, DNA content and expression of PS. AL-I could stimulate the secretion of FN and TGF-beta1. The potency of AL-I cell toxicity was higher than AA-I at the same concentration. The effects of AL-I on apoptosis, secretion of FN and TGF-beta1 were all weaker than AA-I.

CONCLUSIONAL-I as one metabolite of AA-I in vivo induces direct injury in renal proximal tubular cells. Its effects are similar to those of AA-I. AL-I may be one of toxic metabolites in Chinese herbs containing AA which participate in renal damage and fibrosis.

Apoptosis ; drug effects ; Aristolochia ; chemistry ; Aristolochic Acids ; administration & dosage ; isolation & purification ; toxicity ; Cell Line ; Cell Membrane ; metabolism ; DNA ; genetics ; Diploidy ; Dose-Response Relationship, Drug ; Epithelial Cells ; drug effects ; Humans ; Kidney Tubules, Proximal ; cytology ; metabolism ; Plants, Medicinal ; chemistry

BACKGROUNDSurfactant protein A (SP-A) contributes to the regulation of sepsis-induced acute lung injury. In a previous study, we demonstrated the expression and localization of SP-A in the kidneys. The present study evaluated the effect of SP-A on lipopolysaccharide (LPS)-induced tumor necrosis factor-a (TNF-α) expression and its underlying mechanisms in the human renal tubular epithelial (HK-2) cells.

METHODSIndirect immunofluorescence assay was used to detect SP-A distribution and expression in HK-2 cells. HK-2 cells were treated with various concentrations of LPS (0, 0.1, 1, 2, 5, and 10 mg/L) for 8 hours and with 5 mg/L LPS for different times (0, 2, 4, 8, 16, and 24 hours) to determine the effects of LPS on SP-A and TNF-α expression. Then, HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB (NF-κB) P65 and TNF-α expression of HK-2 cells after LPS-treatment.

RESULTSIndirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells. Interestingly, SP-A1/SP-A2 and TNF-a expression were found to be significantly increased in HK-2 cells upon LPS treatment. Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.

CONCLUSIONSP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.

Cell Line ; Epithelial Cells ; cytology ; drug effects ; metabolism ; Fluorescent Antibody Technique, Indirect ; Humans ; Kidney Tubules, Proximal ; cytology ; Lipopolysaccharides ; pharmacology ; Pulmonary Surfactant-Associated Protein A ; metabolism ; pharmacology ; Tumor Necrosis Factor-alpha ; metabolism

The pathogenesis of chronic cyclosporine A (CsA) nephrotoxicity has not been elucidated, but apoptosis is thought to play an important role in CsA induced tubular atrophy. Recently Fas-Fas ligand system mediated apoptosis has been frequently reported in many epithelial cells as well as in T lymphocytes. We investigated the ability of CsA to induce apoptosis in cultured human proximal tubular epithelial cells and also the effect of -MSH on them. Fas, Fas ligand, and an intracellular adaptor protein, Fas-associating protein with death domain (FADD) expression, and poly-ADP ribose polymerase (PARP) cleavage were also studied. CsA induced apoptosis in cultured tubular epithelial cells demonstrated by increased number of TUNEL positive cells and it was accompanied by a significant increase in Fas mRNA and Fas ligand protein expressions. FADD and the cleavage product of PARP also increased, indicating the activation of caspase. In -MSH co-treated cells, apoptosis markedly decreased with downregulation of Fas, Fas ligand and FADD expressions and also the cleavage product of PARP. In conclusion, these data suggest that tubular cell apoptosis mediated by Fas system may play a role in tubular atrophy in chronic CsA nephrotoxicity and pretreatment of -MSH may have a some inhibitory effect on CsA induced tubular cell apoptosis.
Antigens, CD95/genetics ; Apoptosis/*drug effects ; Carrier Proteins/biosynthesis ; Caspases/physiology ; Cells, Cultured ; Cyclosporine/*toxicity ; Human ; Immunosuppressive Agents/*toxicity ; Kidney Tubules, Proximal/cytology/*drug effects/metabolism ; Membrane Glycoproteins/biosynthesis ; NAD+ ADP-Ribosyltransferase/metabolism ; RNA, Messenger/analysis ; alpha-MSH/*pharmacology

AIMTo explore effects of Ginsenosides (Rb1, Rg1) on the expression of Bcl-2, Bax in the serum of kidney ischemia/reperfusion inducing apoptosis of HK-2 cells.

METHODSThe serum of rabbits with renal ischemia/reperfusion (SIR) and the control serum of rabbits (SC) were acquired and cultured with HK-2 cells. Detected apoptosis with TUNEL assay. The experiment was designed as: control group,ischemia/ reperfusion group, Rb1 blocking group and Rg1 blocking group. To detect the expression of Bcl-2, Bax with immunocytochemistry after 24 hours' cultured.

RESULTSThe expression of Bax in Rb1 blocking group and Rg1 blocking group were significantly decreased (P < 0.01), the ratios of Bcl-2/Bax were increased as compared with ischemia/reperfusion group.

CONCLUSIONRb1 and Rg1 have protective effects on apoptosis of HK-2 cells induced by serum of kidney ischemia/reperfusion.

Animals ; Apoptosis ; drug effects ; Cell Line ; Female ; Ginsenosides ; pharmacology ; Ischemia ; blood ; Kidney ; blood supply ; Kidney Tubules, Proximal ; cytology ; Male ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Rabbits ; Reperfusion Injury ; blood ; Serum ; physiology ; bcl-2-Associated X Protein ; genetics ; metabolism