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

OBJECTIVETo study effects of Chinese Herbal Compounds (CHC) for blood activating stasis removing (BASR), qi benefiting Shen invigorating (QBSI) on high glucose stimulated proliferation of renal mesangial cells (RMCs) and expressions of fibronectin (FN).

METHODSRats' RMCs were dealt with high glucose and different concentrations of Chinese medicine for 24 and 48 h respectively. The proliferation of RMCs was detected with 4-A thiazolyl blue. mRNA expressions of FN was detected by real time quantitative PCR. The protein expression of FN was detected by ELISA.

RESULTSCompared with the control group, the proliferation obviously increased (P < 0.05, P < 0.01) after 24 and 48 h of treatment in the high glucose group, mRNA and protein expressions of FN also increased (P < 0.01). There was no statistical difference in the proliferation of RMCs or expressions of FN at 24 h between each CHC group and the high glucose group (P > 0.05). Compared with the high glucose group, the proliferation of RMCs and expressions of FN at 24 h each obviously decreased in the CHC group (P < 0.05, P < 0.01).

CONCLUSIONSHigh glucose could promote the proliferation of RMCs and induce expressions of FN. No obvious effect could be stimulated by CHC treatment for 24 h. The proliferation of RMCs, protein and mRNA expressions of FN could be reversed by CHC treatment for 48 h.

Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Fibronectins ; metabolism ; Glucose ; adverse effects ; Kidney Tubules ; cytology ; Male ; Mesangial Cells ; drug effects ; metabolism ; RNA, Messenger ; genetics ; Rats

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 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

OBJECTIVETo study the biological impact and mechanism of recombinant tissue factor pathway inhibitor (rTFPI) on apoptosis of rat kidney mesangial cells (MsC).

METHODSTFPI expression in human glomerular minor lesion (GML), mesangial proliferative glomerulonephritis (MPGN) and cultured rat MsC was detected using immunohistochemistry and immunofluorescence, respectively. Rat MsC were incubated with rTFPI and its variant peptides. Morphological changes of apoptosis were investigated by Hoechst 33258 and the apoptotic rate was assessed by flow cytometry. DNA fragmentation and effect of rTFPI on expression of caspase-3, Fas and bcl-2 were studied using gel electrophoresis and Western blot respectively.

RESULTSThe expression of TFPI in MPGN was higher than that in GML. TFPI was expressed in cultured rat mesangial cells. Apoptosis of MsC was induced by rTFPI, especially by its C-termianl, in a dose- and time-dependent manner. Apoptosis ratios of MsC treated with rTFPI were 2.1, 3.0 and 4.9 times more than control, respectively. Expression of gene caspase-3 and Fas was up-regulated in a dose-dependent manner wherease bcl-2 expression did not show any changes.

CONCLUSIONrTFPI induces apoptosis in cultured rat mesangial cells by its C-terminal possibly via Fas/FasL pathway.

Animals ; Apoptosis ; drug effects ; physiology ; Caspase 3 ; metabolism ; Cells, Cultured ; drug effects ; DNA Fragmentation ; Flow Cytometry ; Humans ; Lipoproteins ; metabolism ; pharmacology ; Mesangial Cells ; cytology ; drug effects ; enzymology ; metabolism ; Peptides ; pharmacology ; Rats ; bcl-Associated Death Protein ; metabolism ; pharmacology

BACKGROUNDThe plasma concentration of very low density lipoprotein (VLDL) is negatively correlated to renal function in glomerular diseases. Effects of VLDL on renal function have been partially attributed to the proliferation of mesangial cells. This study examined the potential role of the p42/44 mitogen activated protein kinase (MAPK) in mesangial cell proliferation induced by VLDL.

METHODSMesangial cells were treated with VLDL at different concentrations or for different time. The cell cycle of the mesangial cells was analyzed by XTT assay and flow-cytometry; MAPK activity was also assayed. In some experiments, cells were treated with VLDL together with or without 0.1 µmol/L PD 98059.

RESULTSTen to 500 µg/ml VLDL stimulated the proliferation of mesangial cells cultured in vitro in a concentration-dependent manner. The effect was associated with an increase in p42/44 MAPK activity. Increased proliferation of mesangial cells by VLDL was significantly attenuated by PD98059, a specific p42/44 MAPK inhibitor.

CONCLUSIONThese results indicate that the p42/44 MAPK pathway is an important regulator of mesangial cell proliferation and of renal functions.

Animals ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Lipoproteins, VLDL ; pharmacology ; Male ; Mesangial Cells ; cytology ; drug effects ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the role of TRB3 in the inhibitory effect of fenofibrate against the proliferation of glomerular mesangial cell induced by high glucose.

METHODSRat glomerular mesangial cells (MCs) were cultured in the presence of 5.5 mmol/L glucose (normal control), 25 mmol/L glucose (high glucose group), or high glucose along with 10, 50, or 100 µmol/L fenofibrate. Cell counting kit-8 (CCK-8) assay was used to evaluate cell proliferation, and Hoechst 33258 staining was employed to determine chromatin distribution in the MCs. Flow cytometry was performed to analyze the cell cycle changes in different groups. The expressions of TRB3 and P-AKT in different groups were detected using immunocytochemistry and Western blotting.

RESULTSHigh glucose induced obvious proliferation of the MCs (P<0.001), which was significantly inhibited by fenofibrate in a concentration-dependent manner (P<0.001). The MCs exposed to fenofibrate presented with typical apoptotic morphologies and cell cycle arrest at G1/S phase. Low levels of TRB3 expression was detected in the normal control and high glucose groups, whereas in the 3 fenofibrate groups, TRB3 expression increased and P-AKT expression decreased as fenofibrate concentration increased.

CONCLUSIONFenofibrate can promote TRB3 expression in rat MCs. TRB3 causes cell cycle arrest at G1/S phase by inhibiting AKT phosphorylation to result in suppressed proliferation of the MCs.

Animals ; Cell Cycle Checkpoints ; Cell Proliferation ; drug effects ; Cells, Cultured ; Fenofibrate ; pharmacology ; Glucose ; adverse effects ; metabolism ; Mesangial Cells ; cytology ; drug effects ; Phosphorylation ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Signal Transduction

AIMTo investigate the effects of NPPB, a chloride channel blocker, on proliferation of mesangial cells.

METHODSCell proliferation was determined by measuring cell number and 3H-thymidine incorporation. The LDH activity released from these cells was measured as evaluation of cell viability. The phase of cell cycle was detected by flow cytometry.

RESULTSCell proliferation assays showed that treatment with both NPPB (50 and 25 micromol x L(-1)) and in hypertonic media (100% increased osmolarity with D-mannitol ) significantly reduced the number of human MC and 3H-thymidine incorporation in a dose-dependent manner. But the LDH activity was not significantly altered in the treatment with 50 micromol x L(-1) NPPB. Flow cytometry experiments showed that 50 and 25 micromol x L(-1) NPPB arrested (84.2 +/- 2.4) % and (80.8 +/- 2.9) % of cells at G0/G1 stage, versus (70.5 +/- 1.4) % of control cells. Conclusion NPPB suppresses cell proliferation and produces growth arrest at G0/G1 phase in human MC by a mechanism probably associated with changes in cell volume.

Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chloride Channels ; antagonists & inhibitors ; Dose-Response Relationship, Drug ; Humans ; L-Lactate Dehydrogenase ; metabolism ; Mesangial Cells ; cytology ; metabolism ; Nitrobenzoates ; administration & dosage ; pharmacology

Early stage diabetic nephropathy is characterized by elevated glomerular filtration. Recent studies have identified high-glucose induced p38 MAPK (p38) over-activation in mesangial cells. Mesangial hypocontractility is the major underlying mechanism, however, no ameliorating agents are currently available. We investigated the protective effects of emodin on high-glucose induced mesangial cell hypocontractility. Mesangial cells were cultured under normal (5.6 mM) and high glucose (30 mM) conditions. Emodin was administrated at doses of 50 mg/l and 100 mg/l. Angiotension II stimulated cell surface reductions were measured to evaluate cell contractility. p38 activity was detected using Western blotting. To further explore the possible mechanism of emodin, expression of the peroxisome proliferator-activated receptor gamma (PPARgamma) was measured and its specific inhibitor, gw9662, was administrated. Our results showed: (1) high-glucose resulted in a 280% increase in p38 activity associated with significant impairment of mesangial contractility; (2) emodin treatment dose-dependently inhibited high-glucose induced p38 over-activation (a 40% decrease for 50 mg/l emodin and a 73% decrease for 100 mg/l emodin), and mesangial hypocontractility was ameriolated by emodin; (3) both the PPARgamma mRNA and protein levels were elevated after emodin treatment; (4) inhibition of PPARgamma using gw9662 effectively blocked the ameliorating effects of emodin on high-glucose induced p38 over-activation and mesangial hypocontractility. Emodin effectively ameliorated p38 over-activation and hypocontractility in high-glucose induced mesangial cells, possibly via activation of PPARgamma.
Animals ; Cell Line ; Cell Physiological Phenomena/drug effects ; Emodin/*pharmacology ; Gene Expression/drug effects ; Glucose/*metabolism ; Mesangial Cells/cytology/*drug effects ; PPAR gamma/genetics/*metabolism ; Protein Kinase Inhibitors/*pharmacology ; Rats ; p38 Mitogen-Activated Protein Kinases/*metabolism

Animals ; Cell Proliferation ; drug effects ; Diabetic Nephropathies ; drug therapy ; Drugs, Chinese Herbal ; pharmacology ; Male ; Mesangial Cells ; cytology ; drug effects ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta ; genetics