OBJECTIVETo investigate the effect of exendin-4 on the expression of monocyte chemoattractant protein-1 (MCP-1) and fibronectin (FN) in rat glomerular mesangial cells in vitro.

METHODSRat glomerular mesangial cells were divided into 5 groups, namely control group, tumor necrosis factor-α (TNF-α) group (10 ng/ml), TNF-α (10 ng/ml)+E1 (1 nmol/L exendin-4) group, TNF-α (10 ng/ml)+E5 (5 nmol/L exendin-4) group, and TNF-α (10 ng/ml)+E10 (10 nmol/L exendin-4) group. After cultured 24 h or 48 h, RNA were extracted to determine the expression of MCP-1 with real-time PCR, the supernatant were collected to determine the expression of MCP-1 and FN with ELISA.

RESULTSCompared with control group, the cells treated with TNF-α for 24 h showed significantly increase the expression of MCP-1 and FN (P<0.01), exendin-4 significantly reduced the expression of MCP-1 and FN in TNF-α+E5 group and TNF-α+E10 group (P<0.05). After 48h incubation, the expression of MCP-1 and FN increased significantly in TNF-α group (P<0.01), which was lowered by exendin-4 in TNF-α+E1,TNF-α+E5 and TNF-α+E10 groups (P<0.05).

CONCLUSIONExendin-4 has an intrinsic capability to concentration- and time-dependently inhibit TNF-α-induced expression of MCP-1 and FN in rat mesangial cells, suggesting the beneficial effect of exendin-4 in preventing and treating diabetic nephropathy.

Animals ; Cells, Cultured ; Chemokine CCL2 ; metabolism ; Diabetic Nephropathies ; metabolism ; Glomerular Mesangium ; cytology ; Mesangial Cells ; drug effects ; metabolism ; Peptides ; pharmacology ; Rats ; Tumor Necrosis Factor-alpha ; pharmacology ; Venoms ; pharmacology

BACKGROUNDThe renoprotective mechanisms of adenosine monophosphate (AMP)-activated protein kinase (AMPK) agonist - metformin have not been stated clearly. We hypothesized that metformin may ameliorate inflammation via AMPK interaction with critical inflammatory cytokines. The aim of this study was to observe the effects of metformin on expression of nuclear factor-κB (NF-κB), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta 1 (TGF-β1) induced by high glucose (HG) in cultured rat glomerular mesangial cells (MCs).

METHODSMCs were cultured in the medium with normal concentration glucose (group NG, 5.6 mmol/L), high concentration glucose (group HG, 25 mmol/L) and different concentrations of metformin (group M1, M2, M3). After 48-hour exposure, the supernatants and MCs were collected. The expression of NF-κB, MCP-1, ICAM-1, and TGF-β1 mRNA was analyzed by real time polymerase chain reaction. Western blotting was used to detect the expression of AMPK, phospho-Thr-172 AMPK (p-AMPK), NF-κB p65, MCP-1, ICAM-1, and TGF-β1 protein.

RESULTSAfter stimulated by HG, the expression of NF-κB, MCP-1, ICAM-1, TGF-β1 mRNA and protein of MCs in group HG increased significantly compared with group NG (P < 0.05). Both genes and protein expression of NF-κB, MCP-1, ICAM-1, TGF-β1 of MCs induced by high glucose were markedly reduced after metformin treatment in a dose-dependent manner (P < 0.05). The expression of p-AMPK increased with the rising of metformin concentration, presenting the opposite trend, while the level of total-AMPK protein was unchanged with exposure to HG or metformin. Conlusion Metformin can suppress the expression of NF-κB, MCP-1, ICAM-1 and TGF-β1 of glomerular MCs induced by high glucose via AMPK activation, which may partly contribute to its reno-protection.

AMP-Activated Protein Kinases ; metabolism ; Animals ; Cells, Cultured ; Glomerular Mesangium ; cytology ; Glucose ; pharmacology ; Mesangial Cells ; drug effects ; metabolism ; Metformin ; pharmacology ; NF-kappa B ; metabolism ; Rats

OBJECTIVETo investigate the effects of rapamycin and 3-methyladenine on autophagy impairment, oxidative stress and premature senescence induced by high-glucose in primarily cultured rat mesangial cells.

METHODSRat glomerular mesangial cells (GMCs) were isolated and cultured in normal glucose, high glucose, high glucose with 3-methyladenine (3-MA), or high glucose with rapamycin. At 24 h, 72 h and 10 days of culture, the cells were examined for expression levels of autophagy markers LC3 and p62/SQSTM1, malondialdehyde (MDA) and protein carbonyl, β-galactosidase (SA-β-gal) activity and heterochromatin foci (SAHF).

RESULTSCompared with those of normal cell culture, the cells exposed to high glucose for 72 h and 10 days showed down-regulated LC3 expression, up-regulated p62/SQSTM1 expression, elevated MDA and protein carbonyl levels, and increased SAHF formation and percentage of SA-β-gal-positive cells. These changes were reversed in GMCs exposed to high glucose and rapamycin for 72 h and 10 days, but exacerbated in cells incubated with 3-MA.

CONCLUSIONHigh glucose can suppress autophagic function of rat GMCs to result in oxidative damage and cell senescence. Rapamycin can attenuate autophagy impairment, oxidative damage and senescence induced by high glucose, whereas 3-MA can further aggravate high glucose-induced cell injuries in rat GMCs.

Animals ; Autophagy ; drug effects ; Cells, Cultured ; Cellular Senescence ; drug effects ; Glomerular Mesangium ; cytology ; Glucose ; adverse effects ; Male ; Mesangial Cells ; cytology ; drug effects ; metabolism ; Oxidative Stress ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sirolimus ; pharmacology

Interleukin (IL)-6 is an autocrine growth factor for mesangial cells. It is not known whether high glucose influences IL-6 production in mesangial cells. Angiotensin II (AGII) is involved in the progression of renal diseases including diabetic nephropathy. Therefore, we evaluated the effects of high glucose in concert with AGII on IL-6 production in human mesangial cells and the modulation by blocking AGII. After 48 hr of culture, IL-6 mRNA expression was analyzed by reverse transcription and polymerase chain reaction (PCR). Quantitative determination of IL-6 concentrations in the culture supernatants of mesangial cells was performed using a sandwich enzyme immunoassay kit. Incubation of mesangial cells with high glucose (450 mg/dL) reduced the ratio of PCR products for IL-6 to beta-actin on densitometric results, while AGII (10(-7)M) increased it. The IL-6 secretion in the supernatant was also increased by AGII and decreased by high glucose. The IL-6 mRNA expression and IL-6 secretion in combination of high glucose and AGII were higher than those in high glucose and similar with those in control media. The addition of losartan (10(-6)M) or captopril (10(-6)M) to high glucose had no additional effects on IL-6 production. These results suggest that whereas AGII increases IL-6 production, high glucose decreases it. The IL-6 production of mesangial cells in diabetic milieu may be complicated and depend on the local effects of high glucose and/or AGII.
Angiotensin II/*pharmacology ; Captopril/pharmacology ; Cells, Cultured ; Gene Expression/drug effects ; Glomerular Mesangium/cytology/*metabolism ; Glucose/*pharmacology ; Humans ; Interleukin-6/*biosynthesis/genetics/secretion ; Losartan/pharmacology

OBJECTIVETo explore effects of beraprost sodium (BPS) on the metabolism of extracellular matrix (ECM) in rat mesangial cells cultured in the presence of high glucose and the possible mechanism.

METHODSRat mesangial cells were cultured in the presence of high glucose with or without BPS for 24 or 48 h. The levels of transforming growth factor β1 (TGFβ1), fibronectin (FN) and matrix metalloproteinase-2 (MMP-2) protein in the culture supernatants were measured by enzyme-linked immunosorbent assay, and photoshop-Smad3 was detected by Western blotting.

RESULTSCompared with the cells in normal glucose, the cells cultured in the presence of high glucose for 24 and 48 h showed significantly increased TGFβ 1 and FN protein expression and lowered MMP-2 protein expression (P<0.01). Compared with the cells cultured in high glucose, BPS exposure at the concentration of 1, 2, and 5 µmol/L for 24 and 48 h significantly lowered TGFβ 1 protein expression (P<0.01), and at 2 and 5 µmol/L, BPS significantly decreased FN protein expression and increased MMP-2 protein expression in high glucose-induced cells (P<0.05). High glucose exposure also significantly increased the expression phosphorylated Smad3 (P<0.01), which was lowered by BPS treatment at 2 and 5 µmol/L (P<0.01).

CONCLUSIONBPS can regulate ECM metabolism in rat mesangial cells cultured in high glucose by inhibiting TGFβ 1/Smad3 pathway, suggesting the beneficial effects of BPS in preventing and treating diabetic nephropathy.

Animals ; Cell Line ; Cells, Cultured ; Diabetic Nephropathies ; Enzyme-Linked Immunosorbent Assay ; Epoprostenol ; analogs & derivatives ; pharmacology ; Extracellular Matrix ; metabolism ; Fibronectins ; metabolism ; Glomerular Mesangium ; cytology ; Glucose ; Matrix Metalloproteinase 2 ; metabolism ; Mesangial Cells ; drug effects ; Rats ; Transforming Growth Factor beta1 ; metabolism

Rapamycin, a macrocyclic lactone, is effective in reducing the incidence of acute rejection after renal transplantation. The inhibitory effects of rapamycin on lymphocyte proliferation and the molecular mechanisms that were involved have been described. However, its effects on glomerular mesangial cells have not been clearly understood, and here, we examined the effect of rapamycin on platelet-derived growth factor (PDGF) - induced extracellular matrix synthesis as well as cell proliferation in mesangial cells. Rat mesangial cells were isolated from the glomeruli of Sprague-Dawley rats and cultured with Dulbecco's modified Eagles medium containing 20% fetal bovine serum. Different concentrations of rapamycin were administered 1 hour before the addition of 10 ng/ml of PDGF into growth arrested and synchronized cells. Cell proliferation was assessed by [3H]thymidine incorporation, total collagen synthesis by [3H]proline incorporation, and fibronectin secretion into the medium by Western blot analysis. In the mesangial cells, PDGF increased cell proliferation by 4.6-fold, total collagen synthesis by 1.8-fold, and fibronectin secretion by 3.2-fold. Rapamycin above 10 nM significantly inhibited PDGF-induced proliferation and collagen synthesis, but the treatment of rapamycin up to 1micrometer did not show any significant effects on PDGF-induced fibronectin secretion. These inhibitory effects of rapamycin on PDGF-induced mesangial cell proliferation and collagen synthesis reflect the potential value of rapamycin in the prevention and treatment of glomerulosclerosis in patients with chronic allograft nephropathy.
Animals ; Cells, Cultured ; Collagen/*antagonists & inhibitors/biosynthesis ; Fibronectins/*biosynthesis ; Glomerular Mesangium/cytology/drug effects/*metabolism ; Immunosuppressive Agents/*pharmacology ; Male ; Platelet-Derived Growth Factor/*pharmacology ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Sirolimus/*pharmacology

OBJECTIVETo observe the effect of Kanglaite injection(KLT) on the proliferation and telomerase activity of mesangial cells in rats.

METHODMTT, telomere repeat amplification protocal (TRAP), ELISA, PAGE and silver-stain were applied to detect the growth rate and telomerase activity of MC after stimulation of KLT and IL-1.

RESULTThe growth rate of MC was enhanced by IL-1 stimulation, which was accompanied with a redection of the activity of telomerase. Adversely, the growth rate of MC was reduced by KLT, which was accompanied with an enhancement of activity of telomerase. Moreover, the growth rate of MC and the activity of telomerase were both inhibited by the combinative use of IL-1 and KLT without any influence from the sequence of their administration.

CONCLUSIONKLT could inhibit proliferation and telomerase activity of MC with or without pre-stimulation with IL-1. KLT might be useful to prevent and treat glomerular nephritis related to MC proliferation.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Coix ; chemistry ; Drugs, Chinese Herbal ; administration & dosage ; isolation & purification ; pharmacology ; Glomerular Mesangium ; cytology ; enzymology ; Injections ; Plant Oils ; administration & dosage ; isolation & purification ; pharmacology ; Plants, Medicinal ; chemistry ; Rats ; Seeds ; chemistry ; Telomerase ; metabolism

Angiotensin II ; pharmacology ; Blotting, Western ; Cells, Cultured ; Glomerular Mesangium ; cytology ; drug effects ; metabolism ; Humans ; I-kappa B Kinase ; NF-kappa B ; analysis ; Peptide Fragments ; pharmacology ; Protein-Serine-Threonine Kinases ; analysis

In order to investigate the anti-proliferative effect of 3-hydroxy-3-methylglutaryl coenzyme. A reductase inhibitor, we evaluated the effects of lovastatin on DNA replication and the proliferation of rat mesangial and aortic smooth muscle cells, both of which were mesenchymal origin cells. Proliferations were determined by measuring [3H]thymidine uptake, and counting the number of cells. Growth-arrested mesangial and aortic smooth muscle cells were exposed to platelet-derived growth factor (PDGF), endothelin (ET) and angiotensin II (Ang II) to stimulate mitogenesis. All agents exhibited dose-dependent stimulation of [3H] thymidine uptake. PDGF was more potent than the others. Ang II increased [3H] thymidine uptake without demonstrable mitogenic activity. Lovastatin inhibited PDGF (10 ng/ml in mesangial cell, 25 ng/ml in smooth muscle cell)-, ET (10(-7)M)- and Ang II (10(-7)M)-induced [3H] thymidine uptake significantly in a dose-dependent manner in both cells. The increase of cell number in response to PDGF and ET treatment were also inhibited at 10 microM of lovastatin. The inhibitory effect of lovastatin was largely overcome in the presence of exogenous mevalonate at 200 microM, with 75.5% restoration from lovastatin-induced inhibition on PDGF-induced [3H] thymidine uptake in mesangial cells (77.8% in aortic smooth muscle cells). However, the addition of cholesterol did not prevent inhibition by lovastatin. In conclusion, lovastatin had an inhibitory effect on mesangial and aortic smooth muscle cell proliferation, and mevalonate was essential for DNA replication in both types of cells. Lovastatin may reduce glomerular and atherosclerotic injury through an anti-proliferative effect on mesangial and vascular smooth muscle cells, in addition to lowering circulating lipids.
Angiotensin II/pharmacology ; Animal ; Aorta/cytology/drug effects ; Cell Division/drug effects ; Cells, Cultured ; Endothelins/pharmacology ; Glomerular Mesangium/cytology/*drug effects ; Lovastatin/*pharmacology ; Male ; Muscle, Smooth, Vascular/cytology/*drug effects ; Platelet-Derived Growth Factor/pharmacology ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't ; Thymidine/metabolism

OBJECTIVEGlomerulosclerosis is characterized by extracellular matrix accumulative and is often associated with mesangial cell proliferation. Curcumin showed a protective effect on anti-glomerular basement membrane (anti-GBM) nephritis in vivo, although their cellular localization and mechanism of action is still unclear. In this study, a glomerular mesangial cell line derived from fetus was used to determine whether curcumin could inhibit the cell proliferation and alter the extracellular matrix turnover.

METHODSThe cell activity was determined with MTT method. Mesangial cells were cultured in vitro and incubated with 0, 3.125, 6.25, 12.5, 25, 50, 100 and 200 micromol/L curcumin. In addition,human mesangial cells were cultured with or without LPS (10 microg/ml) in presence or absence of various concentrations of curcumin (4, 16 and 200 micromol/L), respectively. The supernatant and cells were collected. Then, the levels of the collagen type IV and III protein in the supernatant were determined by using enzyme-linked immunosorbent assay and the IL-1 beta and MCP-1 mRNA in the cells was measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) after subconfluent quiescent mesangial cells were incubated with various concentrations of curcumin for 24 h in vitro.

RESULTSCurcumin at the concentration equal to or over 6.25 micro mol/L was able to inhibit the proliferation of mesangial cells in a dose-dependent manner, the optical density according to the sequential concentrations of curcumin was 0.65 +/- 0.02, 0.62 +/- 0.04, 0.56 +/- 0.01, 0.53 +/- 0.02, 0.51 +/- 0.03, 0.44 +/- 0.05, 0.41 +/- 0.07 and 0.38 +/- 0.06. Without any stimulation, human mesangial cells secreted some collagen type IV and III (10 +/- 9.13 ng/ml and 29.5 +/- 0.58 ng/ml, respectively) and expressed some MCP-1 mRNA, but did not express IL-1 beta mRNA. LPS increased the expression of collagen type IV and III in the culture medium of mesangial cells in vitro [(138.75 +/- 23.23) ng/ml and (38.25 +/- 5.38) ng/ml] and up-regulated the IL-1 beta and MCP-1 mRNA expression [(16.91 +/- 1.68)% and (76.6 +/- 6.59)%]. Yet curcumin could significantly decrease collagen type IV and III in the supernatant of cultured mesangial cells induced by LPS (20.5 +/- 1.00, P < 0.05 and 20.5 +/- 4.12 ng/ml, P < 0.05) and down-regulated the mRNA expression of IL-1 beta and MCP-1 in mesangial cells induced by LPS (P < 0.01).

CONCLUSIONCurcumin could inhibit the human mesangial cell proliferation and alter the extracellular matrix turnover, meanwhile it could down-regulate the IL-1 beta and MCP-1 mRNA expression induced by LPS, which may be valuable in decreasing the progression of glomerulosclerosis.

Anti-Inflammatory Agents, Non-Steroidal ; pharmacology ; Cell Division ; drug effects ; Cells, Cultured ; Chemokine CCL2 ; genetics ; Collagen Type III ; analysis ; drug effects ; Collagen Type IV ; analysis ; drug effects ; Curcumin ; pharmacology ; Dose-Response Relationship, Drug ; Glomerular Mesangium ; cytology ; drug effects ; metabolism ; Humans ; Interleukin-1 ; genetics ; RNA, Messenger ; drug effects ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction