Animals ; Cell Line ; Diabetic Nephropathies ; metabolism ; Epithelial-Mesenchymal Transition ; drug effects ; Eukaryotic Initiation Factor-2 ; metabolism ; Glucose ; pharmacology ; Humans ; Kidney ; drug effects ; metabolism ; pathology ; Kidney Tubules, Proximal ; drug effects ; metabolism ; Rats ; Signal Transduction ; drug effects

OBJECTIVETo investigate the effects of microRNA-145 (miR-145) on epithelial-mesenchymal transition (EMT) of TGF-β1-induced human renal proximal tubular epithelial (HK-2) cells.

METHODSThe gene sequence of miR-145 was synthesized and cloned into pCMV-myc to construct recombinant plasmid pCMV-miR-145. HK-2 cells were divided into four groups: control (untreated), TGF-β1 (treated with TGF-β1), blank+TGF-β1 (treated with TGF-β1 after HK-2 cells transfected with blank plasmid) and miR-145+TGF-β1 (treated with TGF-β1 after HK-2 cells transfected with pCMV-miR-145 recombinant plasmid). Expression of miR-145 was detected by real-time PCR (RT-PCR). TGF-β1, Smad3, Smad2/3, p-Smad2/3, α-SMA, FN and type I collagen (Col I) protein levels were detected by Western blot. Concentrations of fibronectin (FN) and Col I in cell culture supernatants were measured using ELISA.

RESULTSpCMV-miR-145 recombinant plasmid was successfully transfected into HK-2 cells. Compared with the control group, the miR-145+TGF-β1 group showed a significant up-regulation in the expression level of miR-145 (P<0.01). However, the TGF-β1 and blank+TGF-β1 groups showed a significant down-regulation in the expression level of miR-145 compared with that in the control and miR-145+TGF-β1 groups (P<0.01). Compared with the TGF-β1 and blank+TGF-β1 groups, the miR-145+TGF-β1 group showed significantly reduced levels of the signal proteins TGF-β1, Smad3, Smad2/3 and p-Smad2/3 (P<0.05), as well as significantly reduced levels of the biomarkers α-SMA, FN and Col I (P<0.05). Meanwhile, concentrations of FN and Col I in cell culture supernatants also decreased (P<0.05).

CONCLUSIONSmiR-145 modulates the EMT of HK-2 cells treated with TGF-β1, possibly by inhibition of the activation of TGF-β-dependent Smad signaling pathway.

Cells, Cultured ; Epithelial Cells ; drug effects ; pathology ; Epithelial-Mesenchymal Transition ; Humans ; Kidney Tubules, Proximal ; drug effects ; pathology ; MicroRNAs ; physiology ; Transforming Growth Factor beta1 ; pharmacology

Systemic lupus erythematosus (SLE) and clear cell renal cell carcinoma (CC-RCC) are serious disorders and usually fatal, and always accompanied with pathological changes in the kidney. Signal-induced proliferation-associated protein 1 (SIPA-1) is a Rap1GTPase activating protein (Rap1GAP) expressed in the normal distal and collecting tubules of the murine kidney. Lupus-like autoimmune disease and leukemia have been observed in SIPA-1 deficient mice, suggesting a pathological relevance of SIPA-1 to SLE and carcinoma in human being. The expression pattern of SIPA-1 is as yet undefined and the pathogenesis of these diseases in humans remains elusive. In this study, we used both immunohistochemistry and quantum dot (QD)-based immunofluorescence staining to investigate the expression of SIPA-1 in renal specimens from SLE and CC-RCC patients. MTT assay and Western blotting were employed to evaluate the effects of SIPA-1 overexpression on the proliferation and apoptosis of renal cell lines. Semi-quantitative reverse transcriptase-PCR (RT-PCR) was applied to examine the changes of hypoxia-inducible factor-1α (HIF-1α) mRNA level. Results showed that SIPA-1 was highly expressed in the proximal and collecting tubules of nephrons in SLE patients compared to normal ones, and similar results were obtained in the specimens of CC-RCC patients. Although SIPA-1 overexpression did not affect cellular proliferation and apoptosis of both human 786-O renal cell carcinoma cells and rat NRK-52E renal epithelial cell lines, RT-PCR results showed that HIF-1α mRNA level was down-regulated by SIPA-1 overexpression in 786-O cells. These findings suggest that SIPA-1 may play critical roles in the pathological changes in kidney, and might provide a new biomarker to aid in the diagnosis of SLE and CC-RCC.
Apoptosis ; Base Sequence ; Cell Line ; Cell Proliferation ; DNA Primers ; GTPase-Activating Proteins ; metabolism ; Humans ; Kidney Tubules, Proximal ; metabolism ; pathology ; Lupus Erythematosus, Systemic ; metabolism ; pathology ; Nuclear Proteins ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

No abstract available.
Asymptomatic Diseases ; Biological Markers/analysis ; Biopsy ; Crystallization ; Fluorescent Antibody Technique ; Humans ; Immunoglobulin Light Chains/*analysis ; Kidney Diseases/*diagnosis/immunology/pathology ; Kidney Tubules, Proximal/*immunology/ultrastructure ; Male ; Microscopy, Electron ; Proteinuria/*diagnosis/immunology/pathology

OBJECTIVETo study effects of Yishen Kangxian Compound (YKC) and benazepril containing serums on HK-2 cells (human renal proximal tubule epithelial cells) in the process of renal tubular epithelial cells to mesenchymal myofibroblasts transdifferentiation (TEMT) by gene chip.

METHODSYKC and benazepril containing serums were prepared. Their inhibitory effects on HK-2 cells in the transforming growth factor-beta1 (TGF-beta1)-induced TEMT process were observed. HK-2 cells were randomly divided into four groups, i.e., the blank control group, the model group, the benazepril group, and the YKC group. The gross RNAs were extracted and purified by taking advantage of the HumanHT-12 v4 of IlluminaBeadChip. Differentially expressed genes were obtained after they were reversely transcribed to cDNA, incorporating biotin labeling probe, hybridized with GeneChip, picture signals of fluorescence in gene array scanned and compared with differential genes by computer analysis.

RESULTSDifferentially expressed genes were successfully identified by gene chip. Compared with the model group, there were 227 differentially expressed genes in the benazepril group, including 118 up-regulated genes and 109 downregulated genes. Compared with the model group, there were 97 differentially expressed genes in the YKC group, including 69 up-regulated genes and 28 down-regulated genes. The Gene Ontology (GO) analysis indicated that YKC was more actively involved in the regulatory process than benazepril in terms of cell damage, apoptosis, growth, NF-KB, protein kinase, neuron, and blood vessel growth.

CONCLUSIONSYKC and benazepril could inhibit the TEMT process of HK-2 cells. But YKC also had taken part in cell damage, apoptosis, growth,and more pathways of early stage TEMT.

Cell Line ; Cell Transdifferentiation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Epithelial Cells ; cytology ; drug effects ; Genomics ; Humans ; Kidney Tubules, Proximal ; cytology ; pathology

OBJECTIVETo explore the different expression of proteins between human clear-cell renal cell carcinoma (ccRCC) cell line RLC-310 and normal renal proximal tubule epithelial cell line HK-2, and to search new differentially expressed proteins of RCC.

METHODSRLC-310 and HK-2 cells were cultured in vitro. The total proteins were separated by ProteomeLab PF 2D protein fractionation system and the differential expression protein fractions of the two cell lines were analyzed and identified by capillary liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS). RT-PCR and Western blot were used to confirm the representative differential expression at mRNA and protein levels.

RESULTSOne hundred and ninty-six differentially expressed proteins were identified. These differentially expressed proteins involved in many aspects, including cell proliferation and anti-apoptosis, energy metabolism, mitochondria reduction and oxidation, oxidative stress and resistance, cell signaling, invasion and adhesion, cytoskeleton and motion, neovascularization, etc. Except for previously reported RCC associated proteins: annexin A2, fatty acid-binding protein, vimentin, fibronectin, and so on, Septin-9 was firstly found highly expressed in RLC-310 cells when compared with that in the HK-2 cells. Moreover, the overexpression of Septin-9 was confirmed by RT-PCR and Western blot analysis at both mRNA and protein levels (P < 0.05).

CONCLUSIONSThe human ccRCC cell line RLC-310 cells display differential protein profiles compared with those of the normal renal cell line HK-2 cells. The identified differential expression proteins are involved in many aspects of RCC development. It is worth further study and elucidate the molecular mechanisms of RCC. The representative differential protein Septin-9 deserves further study its role in the angiogenesis of ccRCC.

Carcinoma, Renal Cell ; metabolism ; pathology ; Cell Line ; Cell Line, Tumor ; Epithelial Cells ; cytology ; metabolism ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Humans ; Kidney Neoplasms ; metabolism ; pathology ; Kidney Tubules, Proximal ; cytology ; Proteomics ; methods ; RNA, Messenger ; metabolism ; Septins ; genetics ; 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

BACKGROUNDEnhanced and prolonged expression of connective tissue growth factor (CTGF) is associated with kidney fibrosis. Parathyroid hormone (PTH) is involved in the genesis of disturbed calcium/phosphate metabolism and ostitis fibrosa in renal failure. PTH activated mitogen-activated protein kinase (MAPK) signaling pathway is present in renal tubular cells. The aim of this study was to identify the mechanism how the signal is transduced to result in extracellular signal-regulated protein kinase (ERK) activation, leading to upregulation of CTGF.

METHODSThe levels of CTGF mRNA and protein in human kidney proximal tubular cells (HK-2) treated with PTH in the presence or absence of the MAPK inhibitor PD98059 were analyzed by quantitative real-time polymerase chain reaction (RT-PCR) and immunoblotting assay. The activation of the CTGF promoter in HK-2 cells was determined by the dual-luciferase assay. The effects of the protein kinase A (PKA) activator 8-Br-cAMP and protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) on MAPK phosphorylation, and the effects of the PKA inhibitor H89 and PKC inhibitor calphostin C on MAPK phosphorylation and CTGF expression were detected by immunoblotting assay.

RESULTSPD98059 inhibited the PTH stimulated expression of CTGF, which strongly suggested that the MAPK signaling pathway plays an important role in the PTH-induced CTGF upregulation in renal tubular cells. A PKA activator as well as PKC activators induced MAPK phosphorylation, and both PKA and PKC inhibitors antagonized PTH-induced MAPK phosphorylation and CTGF expression.

CONCLUSIONCTGF expression is upregulated by PTH through a PKC/PKA-ERK-dependent pathway.

Cells, Cultured ; Connective Tissue Growth Factor ; genetics ; physiology ; Cyclic AMP-Dependent Protein Kinases ; physiology ; Extracellular Signal-Regulated MAP Kinases ; physiology ; Fibrosis ; Flavonoids ; pharmacology ; Humans ; Kidney Tubules, Proximal ; metabolism ; pathology ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinases ; physiology ; Parathyroid Hormone ; pharmacology ; Phosphorylation ; Protein Kinase C ; physiology

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

In this study, we assessed the effects of shear stress on the expression of plasminogen activator(tPA and uPA) mRNA in cultured NRK-52E cells (a kidney proximal tubular epithelial cell line of normal rat origin) and investigated the mechanism of tubulointerstitial extracellular matrix (ECM) remodeling in the early stage of diabetic nephropathy (DN). The cultured NRK-52E cells were exposed to shear stress of 5 and 10 dyn/cm2 for 1, 3 and 6 hours respectively. Semi-quantity RT-PCR was used to detect the expression of tPA and uPA mRNA. Shear stress down-regulated the expression of tPA and uPA mRNA in cultured NRK-52E cells in a magnitude and time-dependent way. The results suggested that the increased tubular shear stress in the early-stage of DN could decrease the expression of tPA and uPA in renal proximal tubular cells, lead to the reduction of tubulointerstitial fibrinolytic activity and involve in the remodeling of ECM.
Animals ; Cell Line ; Diabetic Nephropathies ; pathology ; Epithelial Cells ; cytology ; metabolism ; pathology ; Extracellular Matrix ; metabolism ; Humans ; Kidney Tubules, Proximal ; cytology ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Shear Strength ; Tissue Plasminogen Activator ; genetics ; metabolism ; Urokinase-Type Plasminogen Activator ; genetics ; metabolism