Regulation of extracellular matrix synthesis by TNF-α and TGF-β1 in type II cells exposed to coal dust

1998 ◽  
Vol 275 (4) ◽  
pp. L637-L644 ◽  
Author(s):  
Yu-Chen Lee ◽  
D. Eugene Rannels
Keyword(s):  
Extracellular Matrix ◽  
Cell Cultures ◽  
Transforming Growth Factor ◽  
Coal Dust ◽  
Transforming Growth Factor Β1 ◽  
Type Ii ◽  
Tnf Α ◽  
Type Ii Cell ◽  
Primary Type ◽  
Tgf Β1

Type II pulmonary epithelial cells respond to anthracite coal dust PSOC 867 with increased synthesis of extracellular matrix (ECM) components. Alveolar macrophages modulate this response by pathways that may involve soluble mediators, including tumor necrosis factor-α (TNF-α) or transforming growth factor-β1 (TGF-β1). The effects of TNF-α (10 ng/ml) and/or TGF-β1 (2 ng/ml) were thus investigated in dust-exposed primary type II cell cultures. In control day 1 or day 3 cultures, TNF-α and/or TGF-β1 had little or no effect on the synthesis of type II cellular proteins, independent of whether the cells were exposed to dust. With PSOC 867 exposure, where ECM protein synthesis is elevated, TNF-α and TGF-β1 further increased both the absolute and relative rates of ECM synthesis on day 3 but had little effect on day 1. Each mediator increased expression of fibronectin mRNA, as well as of ECM fibronectin content, in a manner qualitatively similar to their effects on synthesis. Thus TNF-α and TGF-β1 modulate both ECM synthesis and fibronectin content in coal dust-exposed type II cell cultures.

scholarly journals Myofibroblast contraction activates latent TGF-β1 from the extracellular matrix

2007 ◽  
Vol 179 (6) ◽  
pp. 1311-1323 ◽  
Author(s):  
Pierre-Jean Wipff ◽  
Daniel B. Rifkin ◽  
Jean-Jacques Meister ◽  
Boris Hinz
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Mechanical Stress ◽  
Protease Activity ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Stress Fibers ◽  
Fibrotic Diseases ◽  
Triton X ◽  
Tgf Β1

The conjunctive presence of mechanical stress and active transforming growth factor β1 (TGF-β1) is essential to convert fibroblasts into contractile myofibroblasts, which cause tissue contractures in fibrotic diseases. Using cultured myofibroblasts and conditions that permit tension modulation on the extracellular matrix (ECM), we establish that myofibroblast contraction functions as a mechanism to directly activate TGF-β1 from self-generated stores in the ECM. Contraction of myofibroblasts and myofibroblast cytoskeletons prepared with Triton X-100 releases active TGF-β1 from the ECM. This process is inhibited either by antagonizing integrins or reducing ECM compliance and is independent from protease activity. Stretching myofibroblast-derived ECM in the presence of mechanically apposing stress fibers immediately activates latent TGF-β1. In myofibroblast-populated wounds, activation of the downstream targets of TGF-β1 signaling Smad2/3 is higher in stressed compared to relaxed tissues despite similar levels of total TGF-β1 and its receptor. We propose activation of TGF-β1 via integrin-mediated myofibroblast contraction as a potential checkpoint in the progression of fibrosis, restricting autocrine generation of myofibroblasts to a stiffened ECM.

H-Ras isoform modulates extracellular matrix synthesis, proliferation, and migration in fibroblasts

2012 ◽  
Vol 302 (4) ◽  
pp. C686-C697 ◽  
Author(s):  
Isabel Fuentes-Calvo ◽  
Ana M. Blázquez-Medela ◽  
Nélida Eleno ◽  
Eugenio Santos ◽  
José M. López-Novoa ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Transforming Growth Factor ◽  
Cell Function ◽  
Transforming Growth Factor Β1 ◽  
Normal Fibroblast ◽  
Akt Activation ◽  
Ras Gtpases ◽  
And Migration ◽  
Tgf Β1 ◽  
Proliferation And Migration

Ras GTPases are ubiquitous plasma membrane transducers of extracellular stimuli. In addition to their role as oncogenes, Ras GTPases are key regulators of cell function. Each of the Ras isoforms exhibits specific modulatory activity on different cellular pathways. This has prompted researchers to determine the pathophysiological roles of each isoform. There is a proven relationship between the signaling pathways of transforming growth factor-β1 (TGF-β1) and Ras GTPases. To assess the individual role of H-Ras oncogene in basal and TGF-β1-mediated extracellular matrix (ECM) synthesis, proliferation, and migration in fibroblasts, we analyzed these processes in embryonic fibroblasts obtained from H-Ras knockout mice ( H-ras−/−). We found that H- ras−/− fibroblasts exhibited a higher basal phosphatidylinositol-3-kinase (PI3K)/Akt activation than wild-type (WT) fibroblasts, whereas MEK/ERK 1/2 activation was similar in both types of cells. Fibronectin and collagen synthesis were higher in H -ras−/− fibroblasts and proliferation was lower in H -ras−/− than in WT fibroblasts. Moreover, H-Ras appeared indispensable to maintain normal fibroblast motility, which was highly restricted in H- ras−/− cells. These results suggest that H-Ras (through downregulation of PI3K/Akt activation) could modulate fibroblast activity by reducing ECM synthesis and upregulating both proliferation and migration. TGF-β1 strongly increased ERK and Akt activation in WT but not in H- ras−/− fibroblasts, suggesting that H-Ras is necessary to increase ERK 1/2 activation and to maintain PI3K downregulation in TGF-β1-stimulated fibroblasts. TGF-β1 stimulated ECM synthesis and proliferation, although ECM synthesis was higher and proliferation lower in H- ras−/− than in WT fibroblasts. Hence, H-Ras activation seems to play a key role in the regulation of these effects.

Extracellular matrix-related genes in kidney after ischemic injury: potential role for TGF-β in repair

1998 ◽  
Vol 275 (6) ◽  
pp. F894-F903 ◽  
Author(s):  
David P. Basile ◽  
Daniel R. Martin ◽  
Marc R. Hammerman
Keyword(s):  
Extracellular Matrix ◽  
Transforming Growth Factor ◽  
Ischemic Injury ◽  
Plasminogen Activator Inhibitor ◽  
Transforming Growth Factor Β1 ◽  
Proximal Tubules ◽  
Plasminogen Activator Inhibitor 1 ◽  
Tgf Β1 ◽  
Pai 1

The renal expression of transforming growth factor-β1 (TGF-β1) is enhanced following induction of ischemic injury in rat. In cultured renal cells, TGF-β stimulates the synthesis of extracellular matrix. To link TGF-β1 expression with the regulation of extracellular matrix postischemia, we characterized the expression of several genes known to regulate extracellular matrix synthesis at various times during recovery from acute ischemic renal injury in rat. Levels of mRNA for plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloprotease-1 (TIMP-1), α1(IV) collagen, and fibronectin-EIIIA (FN-EIIIA) mRNAs were significantly enhanced in kidneys within 12 h to 3 days after injury and remained elevated at 7–28 days postischemia relative to levels in kidneys of sham-operated controls. PAI-1 mRNA and peptide were localized in regenerating proximal tubules at 3 and 7 days postischemic injury. α1(IV) Collagen and FN-EIIIA mRNAs were expressed primarily in regenerating proximal tubule cells. Immunoreactivity for FN-EIIIA was enhanced in the tubular basement membrane (TBM) of regenerating proximal tubules, and α1(IV) collagen immunoreactivity was detected in thickened tubulointerstitial spaces. In contrast, TIMP-1 immunoreactivity was enhanced in distal nephron structures postischemia. Immunoneutralization of TGF-β in vivo attenuated the increases in FN-EIIIA, α1(IV) collagen, PAI-1, and TIMP-1 mRNAs by 52%, 73%, 43%, and 27%, respectively. These data are consistent with TGF-β expression postischemic injury participating in renal regeneration of extracellular matrix homeostasis in the proximal TBM.

scholarly journals Down-regulation of Human Type II Collagen Gene Expression by Transforming Growth Factor-β1 (TGF-β1) in Articular Chondrocytes Involves SP3/SP1 Ratio

2002 ◽  
Vol 277 (46) ◽  
pp. 43903-43917 ◽  
Author(s):  
Christos Chadjichristos ◽  
Chafik Ghayor ◽  
Jean-François Herrouin ◽  
Leena Ala-Kokko ◽  
Gunthram Suske ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Articular Chondrocytes ◽  
Type Ii Collagen ◽  
Transforming Growth Factor Β1 ◽  
Collagen Gene ◽  
Type Ii ◽  
Human Type ◽  
Tgf Β1

scholarly journals Acetaldehyde stimulates the activation of latent transforming growth factor-β1 and induces expression of the type II receptor of the cytokine in rat cultured hepatic stellate cells

2002 ◽  
Vol 368 (3) ◽  
pp. 683-693 ◽  
Author(s):  
Anping CHEN
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Stellate Cells ◽  
Transforming Growth Factor Β1 ◽  
Collagen Gene ◽  
Type Ii ◽  
Underlying Mechanisms ◽  
Tgf Β1

Acetaldehyde, the major active metabolite of alcohol, induces the activation of hepatic stellate cells (HSC), leading to over-production of α1(I) collagen and ultimately causing hepatic fibrosis. The underlying mechanisms of this process remain largely unknown. Transforming growth factor-β1 (TGF-β1) is a potent inducer of α1(I) collagen production. Accumulating evidence has shown a potential role for TGF-β1 in alcohol-induced hepatic fibrogenesis. The aims of this study were to determine the effect of acetaldehyde on TGF-β signalling, to elucidate the underlying mechanisms as well as to evaluate its role in expression of α1(I) collagen gene in cultured HSC. It was hypothesized that acetaldehyde activated TGF-β signalling by inducing the expression of elements in the TGF-β signal transduction pathway, which might contribute to α1(I) collagen gene expression in cultured HSC. Initial results revealed that acetaldehyde activated TGF-β signalling in cultured HSC. Additional studies demonstrated that acetaldehyde stimulated the secretion and activation of latent TGF-β1, and induced the expression of the type II TGF-β receptor (Tβ-RII). Further experiments found cis- and trans-activating elements responsible for Tβ-RII gene expression induced by acetaldehyde. Activation of TGF-β signalling by acetaldehyde contributed to α1(I) collagen gene expression in cultured HSC. In summary, this report demonstrated that acetaldehyde stimulated TGF-β signalling by increasing the secretion and activation of latent TGF-β1 as well as by inducing the expression of Tβ-RII in cultured HSC. Results from this report provided a novel insight into mechanisms by which acetaldehyde stimulated the expression of α1(I) collagen in HSC and a better understanding of effects of alcohol (or acetaldehyde) on hepatic fibrogenesis.

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