EGFR-PLCγ1 signaling mediates high glucose-induced PKCβ1-Akt activation and collagen I upregulation in mesangial cells

2009 ◽  
Vol 297 (3) ◽  
pp. F822-F834 ◽  
Author(s):  
D. Wu ◽  
F. Peng ◽  
B. Zhang ◽  
A. J. Ingram ◽  
D. J. Kelly ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
High Glucose ◽  
Mesangial Cells ◽  
Growth Factor Receptor ◽  
Northern Blotting ◽  
Diabetic Rats ◽  
Collagen I ◽  
Small Interference Rna ◽  
Akt Activation

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We have recently shown that epidermal growth factor receptor (EGFR) transactivation mediates high glucose (HG)-induced collagen I upregulation through PI3K-PKCβ1-Akt signaling in mesangial cells (MC). Phospholipase Cγ1 (PLCγ1) interacts with activated growth factor receptors and activates classic PKC isoforms. We thus studied its role in HG-induced collagen I upregulation in MC. Primary rat MC were treated with HG (30 mM) or mannitol as osmotic control. Protein kinase activation was assessed by Western blotting and collagen I upregulation by Northern blotting. Diabetes was induced in rats by streptozotocin. HG treatment for 1 h led to PLCγ1 membrane translocation and Y783 phosphorylation, both indicative of its activation. Mannitol was without effect. PLCγ1 Y783 phosphorylation was also seen in cortex and glomeruli of diabetic rats. HG induced a physical association between EGFR and PLCγ1 as identified by coimmunoprecipitation. PLCγ1 activation required EGFR kinase activity since it was prevented by the EGFR inhibitor AG1478 or overexpression of kinase-inactive EGFR (K721A). Phosphoinositide-3-OH kinase inhibition also prevented PLCγ1 activation. HG-induced Akt S473 phosphorylation, effected by PKCβ1, was inhibited by the PLCγ inhibitor U73122. PLCγ1 inhibition or downregulation by small interference RNA also prevented HG-induced collagen I upregulation. Our results indicate that EGFR-PLCγ1 signaling mediates HG-induced PKCβ1-Akt activation and subsequent collagen I upregulation in MC. Inhibition of EGFR or PLCγ1 may provide attractive therapeutic targets for the treatment of diabetic nephropathy.

HB-EGF release mediates glucose-induced activation of the epidermal growth factor receptor in mesangial cells

2011 ◽  
Vol 300 (4) ◽  
pp. F921-F931 ◽  
Author(s):  
L. Uttarwar ◽  
F. Peng ◽  
D. Wu ◽  
S. Kumar ◽  
B. Gao ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mesangial Cells ◽  
Growth Factor Receptor ◽  
Egfr Transactivation ◽  
Akt Activation ◽  
Epidermal Growth ◽  
Tgf Β1

Glomerular matrix accumulation is a hallmark of diabetic nephropathy. We showed that transactivation of the epidermal growth factor receptor (EGFR) is an important mediator of matrix upregulation in mesangial cells (MC) in response to high glucose (HG). Here, we study the mechanism of EGFR transactivation. In primary MC, EGFR transactivation by 1 h of HG (30 mM) was unaffected by inhibitors of protein kinase C, reactive oxygen species, or the angiotensin II AT1 receptor. However, general metalloprotease inhibition, as well as specific inhibitors of heparin-binding EGF-like growth factor (HB-EGF), prevented both EGFR and downstream Akt activation. HB-EGF was released into the medium by 30 min of HG, and this depended on metalloprotease activity. One of the metalloproteases shown to cleave proHB-EGF is ADAM17 (TACE). HG, but not an osmotic control, activated ADAM17, and its inhibition prevented EGFR and Akt activation and HB-EGF release into the medium. siRNA to either ADAM17 or HB-EGF prevented HG-induced EGFR transactivation. We previously showed that EGFR/Akt signaling increases transforming growth factor (TGF)-β1 transcription through the transcription factor activator protein (AP)-1. HG-induced AP-1 activation, as assessed by EMSA, was abrogated by inhibitors of metalloproteases, HB-EGF and ADAM17. HB-EGF and ADAM17 siRNA also prevented AP-1 activation. Finally, these inhibitors and siRNA prevented TGF-β1 upregulation by HG. Thus, HG-induced EGFR transactivation in MC is mediated by the release of HB-EGF, which requires activity of the metalloprotease ADAM17. The mechanism of ADAM17 activation awaits identification. Targeting upstream mediators of EGFR transactivation including HB-EGF or ADAM17 provides novel therapeutic targets for the treatment of diabetic nephropathy.

scholarly journals Protective Effects of Luteolin on Diabetic Nephropathy in STZ-Induced Diabetic Rats

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Guo Guang Wang ◽  
Xiao Hua Lu ◽  
Wei Li ◽  
Xue Zhao ◽  
Cui Zhang
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
High Glucose ◽  
Transforming Growth Factor ◽  
Antioxidant Properties ◽  
Diabetic Rats ◽  
Heme Oxygenase 1 ◽  
Protective Effects ◽  
Sod Activity ◽  
Matrix Expression

Diabetic nephropathy is a long-term complication of diabetic mellitus. Many experimental evidences suggest that persistent hyperglycaemia generates intracellular reactive oxygen species (ROS) and upregulates transforming growth factor-b1 and extracellular matrix expression in mesangial and tubular epithelial cells, which is involved of free radicals in the pathogenesis of diabetes and more importantly in the development of diabetic complications. Antioxidants effectively inhibit high-glucose- and H2O2-induced transforming growth factor-b1 and fibronectin upregulation, thus providing evidence that ROS play an important role in high glucose-induced renal injury. The flavonoid luteolin has been shown to possess direct antioxidant activity, therefore we hypothesize that it may be useful in treatment of many chronic disease associated with oxidative stress, such as diabetic nephropathy via its antioxidant properties. Our results suggested that protection against development of diabetic nephropathy by luteolin treatment involved changes in superoxide dismutase (SOD) activity, the malondialdehyde (MDA) content and expression of Heme Oxygenase-1 (HO-1) protein.

scholarly journals Expression of vascular endothelial growth factor in response to high glucose in rat mesangial cells

2000 ◽  
Vol 165 (3) ◽  
pp. 617-624 ◽  
Author(s):  
NH Kim ◽  
HH Jung ◽  
DR Cha ◽  
DS Choi
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Diabetic Nephropathy ◽  
Growth Factor ◽  
High Glucose ◽  
Mesangial Cells ◽  
Vascular Endothelial ◽  
Vegf Expression ◽  
Protein Levels ◽  
Calphostin C ◽  
Endothelial Growth Factor

Diabetic nephropathy associated with hyperglycemia is characterized by glomerular hyperfiltration and endothelial dysfunction. Vascular endothelial growth factor (VEGF) is known to be primarily involved in neoangiogenesis and increased endothelial permeability. The purpose of this study was to investigate VEGF expression in response to high glucose in rat cultured mesangial cells and to identify its signal pathway via protein kinase C (PKC). Rat mesangial cells were cultured with different concentrations of glucose: normal (5 mM d-glucose), medium (15 mM d-glucose) and high (30 mm d-glucose). Calphostin-C as a PKC inhibitor and phorbol myristate acetate (PMA) as a PKC downregulator were instillated into culture media to evaluate the role of PKC in mediating the glucose-induced increase in VEGF expression. High glucose increased expression of VEGF at the mRNA and protein levels, identified by semi-quantitative RT-PCR and western blotting, within 3 h and in a time- and glucose concentration-dependent manner. Calphostin-C and PMA inhibited glucose-induced increases in VEGF expression at the mRNA and protein levels. In conclusion, high glucose can directly increase VEGF expression in rat mesangial cells via a PKC-dependent mechanism. These results suggest that VEGF could be a potential mediator of glomerular hyperfiltration and proteinuria in diabetic nephropathy.

Proteomic profile of primary isolated rat mesangial cells in high-glucose culture condition and decreased expression of PSMA6 in renal cortex of diabetic ratsThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process.

2010 ◽  
Vol 88 (4) ◽  
pp. 635-648 ◽  
Author(s):  
Zhiguo Li ◽  
Haojun Zhang ◽  
Xi Dong ◽  
Frank J. Burczynski ◽  
Patrick Choy ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
High Glucose ◽  
Gel Electrophoresis ◽  
Renal Cortex ◽  
Mesangial Cells ◽  
Diabetic Rats ◽  
Differentially Expressed ◽  
Differentially Expressed Proteins ◽  
Two Dimensional Gel Electrophoresis ◽  
Isolated Rat

Diabetic nephropathy (DN) is one of the most important complications of diabetic patients and is characterized histologically by an accumulation of extracellular matrix (ECM) protein in the glomerular mesangium. Therefore, mesangial cells likely play an important role in the development of diabetic nephropathy. Here, we employed proteomic techniques to investigate the protein profile of rat mesangial cells under high-glucose culture conditions. Primary isolated rat glomerular mesangial cells were cultured under different concentrations of glucose (5.4 mmol·L–1 for normal control and 30 mmol·L–1 for high glucose) for 0, 8, 16, and 72 h, as well as for 25 days. Cellular total proteins were isolated from these cells and employed for two-dimensional gel electrophoresis (2-DE). Differentially expressed proteins were identified by matrix-assisted laser desorption – ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and some of these proteins were documented in rat models of diabetes by Western blot. Rat mesangial cells were successfully isolated in the laboratory and their proliferation rates were significantly inhibited by high glucose. Two-dimensional gel electrophoresis analyses revealed 28 differentially expressed protein spots between the normal and high-glucose groups. After MALDI-TOF-MS analysis, all 28 protein spots were successfully identified with the peptide mass fingerprint (PMF) method. Representatively, SOD1, PCBP1 and PSMA6 were validated by Western blot analysis following protein extractions from the normal and high-glucose groups. Abundance of these proteins was consistent with that found in 2-DE. Moreover, expression of SOD1, PCBP1, and PSMA6 in renal cortex was further examined in two rat models of diabetes (streptozotocin-induced and spontaneous OLETF diabetic models). Abundance of SOD1 and PCBP1 proteins did not show any significant difference between normal control and diabetic rats. However, abundance of the PSMA6 protein was significantly reduced in the renal cortex of both STZ-induced and spontaneous OLETF diabetic rats. Proteomic analysis identified 28 differentially expressed proteins in primary isolated rat mesangial cells between normal and high glucose treatments. Expression of one identified protein was found to be consistent with expression in the renal cortex of two rat diabetic models. Therefore, identification of protein expression patterns in mesangial cells can be employed to develop a therapeutic target for treatment of diabetic nephropathy.

Mechanisms through which bradykinin promotes glomerular injury in diabetes

2005 ◽  
Vol 288 (3) ◽  
pp. F483-F492 ◽  
Author(s):  
Yan Tan ◽  
Bing Wang ◽  
Joo-Seob Keum ◽  
Ayad A. Jaffa
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Tissue Growth ◽  
Collagen I ◽  
Mrna Levels ◽  
Glomerular Injury ◽  
Western Blots ◽  
Protein Levels

In diabetes, mesangial cell proliferation and extracellular matrix expansion are critical components in the development of glomerulosclerosis. We reported that diabetes alters the activity of the kallikrein-kinin system and that these alterations contribute to the development of diabetic nephropathy. The present study examined the influence of streptozotocin-induced diabetes on the renal expression of bradykinin (BK) B2 receptors (B2KR), connective tissue growth factor (CTGF), transforming growth factor-β (TGF-β), and TGF-β type II receptor (TGF-βRII) and assessed the signaling mechanisms through which B2KR activation may promote glomerular injury. Eight weeks after the induction of diabetes, renal mRNA levels of B2KR, CTGF, and TGF-β as well as protein levels of CTGF and TGF-βRII were measured in control (C), diabetic (D), and insulin-treated diabetic (D+I) rats. Renal B2KR and TGF-β mRNA levels expressed relative to β-actin mRNA levels and CTGF and TGF-βRII protein levels were significantly increased in D and D+I rats compared with C rats ( P < 0.03, n = 5). To assess the contribution of B2KR activation on modulating the expression of CTGF, TGF-βRII, and collagen I, mesangial cells (MC) were treated with BK (10−8 M) for 24 h and CTGF and TGF-βRII protein levels were measured by Western blots and collagen I mRNA levels were measured by RT-PCR. A two- to threefold increase in CTGF and TGF-βRII protein levels was observed in response to BK stimulation ( P < 0.001, n = 6). In addition, a marked increase in collagen I mRNA levels was observed in response to BK stimulation. Treatment of MC with BK (10−8 M) for 5 min significantly increased the tyrosine phosphorylation of p60src kinase and of p42/p44 MAPK ( P < 0.05, n = 4). Inhibition of src kinase by PP1 (10 μM) inhibited the increase in p42/p44 MAPK activation in response to BK. Finally, to determine whether BK stimulates CTGF, TGF-βRII, and collagen I expression via activation of MAPK pathways, MC were pretreated with an inhibitor of p42/p44 MAPK (PD-98059) for 45 min, followed by BK (10−8 M) stimulation for 24 h. Selective inhibition of p42/p44 MAPK significantly inhibited the BK-induced increase in CTGF, TGF-βRII, and collagen I levels. These findings are the first to demonstrate that BK regulates the expression of CTGF, TGF-βRII, and collagen I in MC and provide a mechanistic pathway through which B2KR activation may contribute to the development of diabetic nephropathy.

scholarly journals Transcriptional Suppression of Diabetic Nephropathy with Novel Gene Silencer Pyrrole-Imidazole Polyamides Preventing USF1 Binding to the TGF-β1 Promoter

2021 ◽  
Vol 22 (9) ◽  
pp. 4741
Author(s):  
Makiyo Okamura ◽  
Noboru Fukuda ◽  
Shu Horikoshi ◽  
Hiroki Kobayashi ◽  
Akiko Tsunemi ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
High Glucose ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Diabetic Rats ◽  
Glomerular Injury ◽  
Upstream Stimulatory Factor ◽  
Injury Score ◽  
Upstream Stimulatory Factor 1 ◽  
Tgf Β1

Upstream stimulatory factor 1 (USF1) is a transcription factor that is increased in high-glucose conditions and activates the transforming growth factor (TGF)-β1 promoter. We examined the effects of synthetic pyrrole-imidazole (PI) polyamides in preventing USF1 binding on the TGF-β1 promoter in Wistar rats in which diabetic nephropathy was established by intravenous administration of streptozotocin (STZ). High glucose induced nuclear localization of USF1 in cultured mesangial cells (MCs). In MCs with high glucose, USF1 PI polyamide significantly inhibited increases in promoter activity of TGF-β1 and expression of TGF-β1 mRNA and protein, whereas it significantly decreased the expression of osteopontin and increased that of h-caldesmon mRNA. We also examined the effects of USF1 PI polyamide on diabetic nephropathy. Intraperitoneal injection of USF1 PI polyamide significantly suppressed urinary albumin excretion and decreased serum urea nitrogen in the STZ-diabetic rats. USF1 PI polyamide significantly decreased the glomerular injury score and tubular injury score in the STZ-diabetic rats. It also suppressed the immunostaining of TGF-β1 in the glomerulus and proximal tubules and significantly decreased the expression of TGF-β1 protein from kidney in these rats. These findings indicate that synthetic USF1 PI polyamide could potentially be a practical medicine for diabetic nephropathy.

High glucose-enhanced activation of mesangial cell p38 MAPK by ET-1, ANG II, and platelet-derived growth factor

2002 ◽  
Vol 282 (1) ◽  
pp. E161-E169 ◽  
Author(s):  
Evangelia Tsiani ◽  
Poli Lekas ◽  
I. George Fantus ◽  
John Dlugosz ◽  
Catharine Whiteside
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Protein Kinase ◽  
High Glucose ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Platelet Derived Growth Factor ◽  
Ang Ii ◽  
Creb Phosphorylation

Mitogen-activated protein kinase (MAPK) p38 is activated in response to stress stimuli and growth factors relevant to the pathogenesis of diabetic nephropathy. We postulated that mesangial cells exposed to high glucose and to endothelin-1 (ET-1), angiotensin II (ANG II), and platelet-derived growth factor (PDGF) demonstrate enhanced p38 activity and subsequent activation of the cAMP responsive element binding (CREB) transcription factor. Primary rat mesangial cells exposed to 5.6 (NG) or 30 mM glucose (HG) or NG plus 24.4 mM sorbitol (osmotic control) for ≤4 days were acutely stimulated with ET-1, ANG II, or PDGF. After 3 days of HG, p38 phosphorylation and kinase activity increased twofold ( P < 0.05 vs. NG, n = 5). No change in p38 activity was observed with sorbitol. In HG, activation of p38 by ET-1, ANG II, or PDGF was enhanced compared with NG and was protein kinase C (PKC) independent. In HG, CREB phosphorylation in response to ET-1, ANG II, and PDGF stimulation was enhanced compared with NG and was abolished by p38 inhibition with SB202190. To conclude, in HG, mesangial cell p38 is activated, which in turn stimulates CREB phosphorylation. Furthermore, in HG, mesangial cell p38 responsiveness to ET-1, ANG II, and PDGF and consequent CREB phosphorylation are enhanced through a PKC-independent pathway, which may contribute to the pathogenesis of diabetic nephropathy.

scholarly journals Circ-ACTR2 aggravates the high glucose-induced cell dysfunction of human renal mesangial cells through mediating the miR-205-5p/HMGA2 axis in diabetic nephropathy

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jie Yun ◽  
Jinyu Ren ◽  
Yufei Liu ◽  
Lijuan Dai ◽  
Liqun Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Nephropathy ◽  
High Glucose ◽  
Cell Injury ◽  
Mesangial Cells ◽  
Protein Detection ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cell Dysfunction

Abstract Background Circular RNAs (circRNAs) have been considered as pivotal biomarkers in Diabetic nephropathy (DN). CircRNA ARP2 actin-related protein 2 homolog (circ-ACTR2) could promote the HG-induced cell injury in DN. However, how circ-ACTR2 acts in DN is still unclear. This study aimed to explore the molecular mechanism of circ-ACTR2 in DN progression, intending to provide support for the diagnostic and therapeutic potentials of circ-ACTR2 in DN. Methods RNA expression analysis was conducted by the quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cell growth was measured via Cell Counting Kit-8 and EdU assays. Inflammatory response was assessed by Enzyme-linked immunosorbent assay. The protein detection was performed via western blot. Oxidative stress was evaluated by the commercial kits. The molecular interaction was affirmed through dual-luciferase reporter and RNA immunoprecipitation assays. Results Circ-ACTR2 level was upregulated in DN samples and high glucose (HG)-treated human renal mesangial cells (HRMCs). Silencing the circ-ACTR2 expression partly abolished the HG-induced cell proliferation, inflammation and extracellular matrix accumulation and oxidative stress in HRMCs. Circ-ACTR2 was confirmed as a sponge for miR-205-5p. Circ-ACTR2 regulated the effects of HG on HRMCs by targeting miR-205-5p. MiR-205-5p directly targeted high-mobility group AT-hook 2 (HMGA2), and HMGA2 downregulation also protected against cell injury in HG-treated HRMCs. HG-mediated cell dysfunction was repressed by miR-205-5p/HMGA2 axis. Moreover, circ-ACTR2 increased the expression of HMGA2 through the sponge effect on miR-205-5p in HG-treated HRMCs. Conclusion All data have manifested that circ-ACTR2 contributed to the HG-induced DN progression in HRMCs by the mediation of miR-205-5p/HMGA2 axis.

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