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.

Expression patterns of connective tissue growth factor and of TGF-β isoforms during glomerular injury recapitulate glomerulogenesis

2010 ◽  
Vol 299 (3) ◽  
pp. F545-F558 ◽  
Author(s):  
Yasuhiko Ito ◽  
Roel Goldschmeding ◽  
Hirotake Kasuga ◽  
Nike Claessen ◽  
Masahiro Nakayama ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Connective Tissue ◽  
Connective Tissue Growth Factor ◽  
Wound Repair ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Expression Patterns ◽  
Tissue Growth ◽  
Glomerular Injury

Transforming growth factor (TGF)-β1, -β2, and -β3 are involved in control of wound repair and development of fibrosis. Connective tissue growth factor (CTGF) expression is stimulated by all TGF-β isoforms and is abundant in glomerulosclerosis and other fibrotic disorders. CTGF is hypothesized to mediate profibrotic effects of TGF-β1 or to facilitate interaction of TGF-β1 with its receptor, but its interactions with TGF-β isoforms in nonpathological conditions are unexplored so far. Tissue repair and remodeling may recapitulate gene transcription at play in organogenesis. To further delineate the relationship between CTGF and TGF-β, we compared expression patterns of CTGF and TGF-β isoforms in rat and human glomerulogenesis and in various human glomerulopathies. CTGF mRNA was present in the immediate precursors of glomerular visceral and parietal epithelial cells in the comma- and S-shaped stages, but not in earlier stages of nephron development. During the capillary loop and maturing glomerular stages and simultaneous with the presence of TGF-β1, -β2, and -β3 protein, CTGF mRNA expression was maximal and present only in differentiating glomerular epithelial cells. CTGF protein was also present on precursors of mesangium and glomerular endothelium, suggesting possible paracrine interaction. Concomitant with the presence of TGF-β2 and -β3 protein, and in the absence of TGF-β1, CTGF mRNA and protein expression was restricted to podocytes in normal adult glomeruli. However, TGF-β1 and CTGF were again coexpressed, often with TGF-β2 and -β3, in particular in podocytes in proliferative glomerulonephritis and also in mesangial cells in diabetic nephropathy and IgA nephropathy (IgA NP). Coordinated expression of TGF-β isoforms and of CTGF may be involved in normal glomerulogenesis and possibly in maintenance of glomerular structure and function at adult age. Prolonged overexpression of TGF-β1 and CTGF is associated with development of severe glomerulonephritis and glomerulosclerosis.

scholarly journals JNK and p38 Inhibitors Prevent Transforming Growth Factor-β1-Induced Myofibroblast Transdifferentiation in Human Graves’ Orbital Fibroblasts

2021 ◽  
Vol 22 (6) ◽  
pp. 2952
Author(s):  
Tzu-Yu Hou ◽  
Shi-Bei Wu ◽  
Hui-Chuan Kau ◽  
Chieh-Chih Tsai
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mapk Pathway ◽  
Transforming Growth Factor Β1 ◽  
Tissue Growth ◽  
Mitogen Activated Protein Kinase ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Western Blots ◽  
Orbital Fibroblasts ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts is known to dominate tissue remodeling and fibrosis in Graves’ ophthalmopathy (GO). However, the signaling pathways through which TGF-β1 activates Graves’ orbital fibroblasts remain unclear. This study investigated the role of the mitogen-activated protein kinase (MAPK) pathway in TGF-β1-induced myofibroblast transdifferentiation in human Graves’ orbital fibroblasts. The MAPK pathway was assessed by measuring the phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) by Western blots. The expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and fibronectin representing fibrogenesis was estimated. The activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) responsible for extracellular matrix (ECM) metabolism were analyzed. Specific pharmacologic kinase inhibitors were used to confirm the involvement of the MAPK pathway. After treatment with TGF-β1, the phosphorylation levels of p38 and JNK, but not ERK, were increased. CTGF, α-SMA, and fibronectin, as well as TIMP-1 and TIMP-3, were upregulated, whereas the activities of MMP-2/-9 were inhibited. The effects of TGF-β1 on the expression of these factors were eliminated by p38 and JNK inhibitors. The results suggested that TGF-β1 could induce myofibroblast transdifferentiation in human Graves’ orbital fibroblasts through the p38 and JNK pathways.

scholarly journals Transplantation of Telocytes Attenuates Unilateral Ureter Obstruction-Induced Renal Fibrosis in Rats

2018 ◽  
Vol 46 (5) ◽  
pp. 2056-2071 ◽  
Author(s):  
Long Zheng ◽  
Long Li ◽  
Guisheng Qi ◽  
Mushuang Hu ◽  
Chao Hu ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protective Effect ◽  
Renal Fibrosis ◽  
Transforming Growth Factor ◽  
Kidney Tissue ◽  
Collagen I ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Mesenchymal Transition ◽  
Tgf Β1

Background/Aims: Previous studies imply that telocytes may have a protective effect on fibrosis in various organs, including the liver, colon, and heart. The effect of telocytes on renal fibrosis remains unknown. Herein, this study was designed to investigate the effect of telocytes on renal fibrosis and the potential mechanisms involved. Methods: In a unilateral ureteral obstruction (UUO)-induced renal fibrosis model, telocytes were injected via the tail vein every other day for 10 days. The degree of renal damage and fibrosis was determined using histological assessment. The expression of collagen I, fibronectin, epithelial-mesenchymal transition markers, and Smad2/3 phosphorylation was examined by western blot analyses. Real-time PCR and enzyme-linked immunosorbent assay were performed in vivo to detect the levels of transforming growth factor (TGF)-β1 and various growth factors. Results: Telocytes attenuated renal fibrosis, as evidenced by reduced interstitial collagen accumulation, decreased expression of fibronectin and collagen I, upregulation of E-cadherin, and downregulation of α-smooth muscle actin. Furthermore, telocytes decreased serum TGF-β1 levels, suppressed Smad2/3 phosphorylation, and increased the expression of hepatocyte growth factor (HGF) in rat kidney tissue following UUO. Blockage of HGF counteracted the protective effect of telocytes on UUO-treated kidneys. Through the detection of HGF mRNA levels in vitro, we found that telocytes had no effect on HGF expression compared with renal fibroblasts. Conclusion: Telocytes attenuated UUO-induced renal fibrosis in rats, likely through enhancing the expression of HGF in an indirect manner.

Role of connective tissue growth factor in the pathogenesis of diabetic nephropathy

2001 ◽  
Vol 359 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Nadia Abdel WAHAB ◽  
Natalia YEVDOKIMOVA ◽  
Benjamin S. WESTON ◽  
Terry ROBERTS ◽  
Xin Jun LI ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Connective Tissue ◽  
High Glucose ◽  
Mesangial Cell ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Growth ◽  
Mrna Levels ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor

We characterized a rabbit polyclonal antibody raised against human recombinant connective tissue growth factor (CTGF). The antibody recognised a higher molecular mass form (approx. 56kDa) of CTGF in mesangial cell lysates as well as the monomeric (36–38kDa) and lower molecular mass forms (< 30kDa) reported previously. Immunohistochemistry detected CTGF protein in glomeruli of kidneys of non-obese diabetic mice 14 days after the onset of diabetes, and this was prominent by 70 days. CTGF protein is also present in glomeruli of human patients with diabetic nephropathy. No CTGF was detected in either normal murine or human glomeruli. Transient transfection of a transformed human mesangial cell line with a CTGF–V5 epitope fusion protein markedly increased fibronectin and plasminogen activator inhibitor-1 synthesis in cultures maintained in normal glucose (4mM) conditions; a CTGF-antisense construct reduced the elevated synthesis of these proteins in high glucose (30mM) cultures. Culture of primary human mesangial cells for 14 days in high glucose, or in low glucose supplemented with recombinant CTGF or transforming growth factor β1, markedly increased CTGF mRNA levels and fibronectin synthesis. However, whilst co-culture with a CTGF-antisense oligonucleotide reduced the CTGF mRNA pool by greater than 90% in high glucose, it only partially reduced fibronectin mRNA levels and synthesis. A chick anti-CTGF neutralizing antibody had a similar effect on fibronectin synthesis. Thus both CTGF and CTGF-independent pathways mediate increased fibronectin synthesis in high glucose. Nevertheless CTGF expression in diabetic kidneys is likely to be a key event in the development of glomerulosclerosis by affecting both matrix synthesis and, potentially through plasminogen activator inhibitor-1, its turnover.

TGF-β and CTGF have overlapping and distinct fibrogenic effects on human renal cells

2002 ◽  
Vol 283 (4) ◽  
pp. F707-F716 ◽  
Author(s):  
Elizabeth Gore-Hyer ◽  
Daniel Shegogue ◽  
Malgorzata Markiewicz ◽  
Shianlen Lo ◽  
Debra Hazen-Martin ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Growth Factors ◽  
Growth Factor ◽  
Renal Fibrosis ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Tissue Growth ◽  
Mrna Levels ◽  
Potent Inducer ◽  
Collagen Promoter

Transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF) are ubiquitously expressed in various forms of tissue fibrosis, including fibrotic diseases of the kidney. To clarify the common and divergent roles of these growth factors in the cells responsible for pathological extracellular matrix (ECM) deposition in renal fibrosis, the effects of TGF-β and CTGF on ECM expression in primary human mesangial (HMCs) and human proximal tubule epithelial cells (HTECs) were studied. Both TGF-β and CTGF significantly induced collagen protein expression with similar potency in HMCs. Additionally, α2(I)-collagen promoter activity and mRNA levels were similarly induced by TGF-β and CTGF in HMCs. However, only TGF-β stimulated collagenous protein synthesis in HTECs. HTEC expression of tenascin-C (TN-C) was increased by TGF-β and CTGF, although TGF-β was the more potent inducer. Thus both growth factors elicit similar profibrogenic effects on ECM production in HMCs, while promoting divergent effects in HTECs. CTGF induction of TN-C, a marker of epithelial-mesenchymal transdifferentiation (EMT), with no significant induction of collagenous protein synthesis in HTECs, may suggest a more predominant role for CTGF in EMT rather than induction of excessive collagen deposition by HTECs during renal fibrosis.

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.

Suppressions of chronic glomerular injuries and TGF-β1 production by HGF in attenuation of murine diabetic nephropathy

2004 ◽  
Vol 286 (1) ◽  
pp. F134-F143 ◽  
Author(s):  
Shinya Mizuno ◽  
Toshikazu Nakamura
Keyword(s):  
Diabetic Nephropathy ◽  
Growth Factor ◽  
Renal Dysfunction ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Renal Diseases ◽  
Glomerular Mesangial Cells ◽  
Diabetic Mice

Diabetic nephropathy is now the leading cause of end-stage renal diseases, and glomerular sclerotic injury is an initial event that provokes renal dysfunction during processes of diabetes-linked kidney disease. Growing evidence shows that transforming growth factor-β1 (TGF-β1) plays a key role in this process, especially in eliciting hypertrophy and matrix overaccumulation. Thus it is important to find a ligand system to antagonize the TGF-β1-mediated pathogenesis under high-glucose conditions. Herein, we provide evidence that hepatocyte growth factor (HGF) targets mesangial cells, suppresses TGF-β1 production, and minimizes glomerular sclerotic changes, using streptozotocin-induced diabetic mice. In our murine model, glomerular sclerogenesis (such as tuft area expansion and collagen deposition) progressed between 6 and 10 wk after the induction of hyperglycemia, during a natural course of diabetic disease. Glomerular HGF expression levels in the diabetic kidney transiently increased but then declined below a basal level, with manifestation of glomerular sclerogenesis. When anti-HGF IgG was injected into mice for 2 wk (i.e., from weeks 4 to 6 after onset of hyperglycemia), these glomerular changes were significantly aggravated. When recombinant HGF was injected into the mice for 4 wk (i.e., between 6 and 10 wk following streptozotocin treatment), the progression of glomerular hypertrophy and sclerosis was almost completely inhibited, even though glucose levels remained unchanged (>500 mg/dl). Even more important, HGF repressed TGF-β1 production in glomerular mesangial cells even under hyperglycemic conditions both in vitro and in vivo. Consequently, not only albuminuria but also tubulointerstitial fibrogenesis were attenuated by HGF. Overall, HGF therapy inhibited the onset of renal dysfunction in the diabetic mice. On the basis of these findings, we wish to emphasize that HGF plays physiological and therapeutic roles in blocking renal fibrogenesis during a course of diabetic nephropathy.

Elevated expression of connective tissue growth factor, osteopontin and increased collagen content in human ascending thoracic aortic aneurysms

Vascular ◽  
2013 ◽  
Vol 22 (1) ◽  
pp. 20-27 ◽  
Author(s):  
YH Meng ◽  
C Tian ◽  
L Liu ◽  
L Wang ◽  
Q Chang
Keyword(s):  
Growth Factor ◽  
Connective Tissue ◽  
Connective Tissue Growth Factor ◽  
Tissue Growth ◽  
Aortic Aneurysms ◽  
Collagen Content ◽  
Control Group ◽  
Mrna Levels ◽  
Thoracic Aortic Aneurysms ◽  
Protein Levels

Little is known about the molecular mechanisms of ascending thoracic aortic aneurysms (ATAAs). Abnormal extracellular matrix changes and variations of vascular smooth muscle cells (VSMCs) have been implicated in abdominal aortic aneurysm formation. Our objective was to investigate the alterations of collagen, stimulators of collagen synthesis and synthetic VSMCs in patients with ATAA. Surgical samples from ATAA were taken from 20 patients, and 18 control aortas were obtained during coronary artery bypass surgery. All aortic wall specimens were fixed for histology and immunohistochemistry for collagen, connective tissue growth factor (CTGF) and osteopontin. Realtime polymerase chain reaction was used to determine their mRNA expression. Histology and semi-quantitative analysis demonstrated that protein levels of collagen, CTGF and osteopontin significantly increased by 1.9-, 1.4- and 2.2-fold, respectively ( P < 0.01 for all) in the ATAA group than in the control group. Similar results were shown in mRNA levels of type Iα1and IIIα1 collagen, CTGF and osteopontin. The protein levels of CTGF and osteopontin were positively correlated with aortic diameter ( r = 0.67, r = 0.73; P < 0.01 for both). In conclusion, overexpression of aortic CTGF and synthetic VSMCs marker (osteopontin), which is likely to be responsible for elevated aortic collagen content, may provide a potential mechanism for aneurysmal enlargement.

Connective tissue growth factor antagonizes transforming growth factor-β1/Smad signalling in renal mesangial cells

2011 ◽  
Vol 441 (1) ◽  
pp. 499-510 ◽  
Author(s):  
Helen C. O'Donovan ◽  
Fionnuala Hickey ◽  
Derek P. Brazil ◽  
David H. Kavanagh ◽  
Noelynn Oliver ◽  
...  
Keyword(s):  
Growth Factor ◽  
Connective Tissue ◽  
Connective Tissue Growth Factor ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Transforming Growth Factor Β1 ◽  
Tissue Growth ◽  
Transcriptional Responses ◽  
Cell Contractility ◽  
Tgf Β1

The critical involvement of TGF-β1 (transforming growth factor-β1) in DN (diabetic nephropathy) is well established. However, the role of CTGF (connective tissue growth factor) in regulating the complex interplay of TGF-β1 signalling networks is poorly understood. The purpose of the present study was to investigate co-operative signalling between CTGF and TGF-β1 and its physiological significance. CTGF was determined to bind directly to the TβRIII (TGF-β type III receptor) and antagonize TGF-β1-induced Smad phosphorylation and transcriptional responses via its N-terminal half. Furthermore, TGF-β1 binding to its receptor was inhibited by CTGF. A consequent shift towards non-canonical TGF-β1 signalling and expression of a unique profile of differentially regulated genes was observed in CTGF/TGF-β1-treated mesangial cells. Decreased levels of Smad2/3 phosphorylation were evident in STZ (streptozotocin)-induced diabetic mice, concomitant with increased levels of CTGF. Knockdown of TβRIII restored TGF-β1-mediated Smad signalling and cell contractility, suggesting that TβRIII is key for CTGF-mediated regulation of TGF-β1. Comparison of gene expression profiles from CTGF/TGF-β1-treated mesangial cells and human renal biopsy material with histological diagnosis of DN revealed significant correlation among gene clusters. In summary, mesangial cell responses to TGF-β1 are regulated by cross-talk with CTGF, emphasizing the potential utility of targeting CTGF in DN.

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