Differences in regulation of type I collagen synthesis in primary and passaged hepatic stellate cell cultures: the role of α5β1-integrin

2007 ◽  
Vol 293 (1) ◽  
pp. G154-G164 ◽  
Author(s):  
Milan Dodig ◽  
Ben Ogunwale ◽  
Srinivasan Dasarathy ◽  
Min Li ◽  
Bingcheng Wang ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Type I Collagen ◽  
Stellate Cell ◽  
Primary Cultures ◽  
Type I ◽  
Collagen Gene ◽  
Direct Role ◽  
Blocking Antibody ◽  
Early Primary

Hepatic stellate cells (HSC) differ in their phenotype depending on the initiation and progression of their activation. Our hypothesis was that different mechanisms govern type I collagen synthesis depending on stage of HSC activation. We investigated the role of α5β1-integrin as a regulator of type I collagen gene COL1A1 expression in primary and passaged HSC cultures using transgenic mouse containing type I collagen gene COL1A1 promoter linked to the chloramphenicol acetyltransferase (CAT) reporter gene. The α5β1 protein levels increased during the activation and were highest in day 6 primary cultures but decreased in passaged HSC. CAT activity, reflecting COL1A1 expression, was upregulated by α5β1-integrin. Inhibition of α5β1-integrin by echistatin and blocking antibody resulted in reduced transgene activity only in early primary cultures (compared with the control, 53.3 ± 12% echistatin and 58.8 ± 7% blocking antibody, respectively, P < 0.05). Treatment of passaged HSC with either echistatin or blocking antibody had no effect. Fibronectin, an α5β1-integrin ligand, increased transgene activity in primary (210 ± 33%, P < 0.05) but not in passaged HSC cultures (119 ± 8%). This α5β1-integrin effect appears to be at least in part mediated by CCAAT enhancer binding protein-β (C/EBPβ), because fibronectin increased and α5-gene silencing by small interfering RNA decreased C/EBPβ levels. In addition, C/EBPβ knockout mice showed reduced type I collagen synthesis compared with wild-type littermates. Therefore α5β1-integrin is an important regulator of type I collagen production in early primary HSC cultures but appears to have no direct role once the HSC are fully activated.

scholarly journals Endothelial cell growth factor and heparin regulate collagen gene expression in keloid fibroblasts

1991 ◽  
Vol 278 (3) ◽  
pp. 863-869 ◽  
Author(s):  
E M L Tan ◽  
J Peltonen
Keyword(s):  
Gene Expression ◽  
Endothelial Cell ◽  
Collagen Synthesis ◽  
Type I Collagen ◽  
Collagen Type ◽  
Collagen Type I ◽  
Type I ◽  
Collagen Gene ◽  
Endothelial Cell Growth Factor ◽  
Endothelial Cell Growth

Keloids are benign cutaneous tumours characterized by excess deposition of collagen, specifically type I collagen. We report here that collagen biosynthesis, as measured by hydroxyproline synthesis, was markedly inhibited by 65-80% by the combination of endothelial cell growth factor (ECGF) supplement and heparin in keloid fibroblast cultures. Fibroblast cultures that were incubated with ECGF alone also demonstrated a measurable decrease of approx. 50% in collagen synthesis compared with control cultures. The inhibition of collagen synthesis was related to the down-regulation of collagen gene expression. Quantitative measurements of mRNA-cDNA hybrids revealed that the gene expression of collagen type I was decreased by more than 80% by heparin and ECGF. Markedly diminished levels of mRNA encoding collagen type I were also observed in cultures incubated with ECGF alone. The results show that ECGF and heparin elicit a negative regulatory effect on collagen production, and that this inhibition is due largely to the down-regulation of the pro-alpha 1(I) of type I collagen gene. Furthermore, ECGF has a potent suppressive effect, and heparin provides an additive effect to this inhibitory phenomenon.

Factors Involved in the Regulation of Type I Collagen Gene Expression: Implication in Fibrosis

2002 ◽  
Vol 227 (5) ◽  
pp. 301-314 ◽  
Author(s):  
Asish K. Ghosh
Keyword(s):  
Gene Expression ◽  
Collagen Synthesis ◽  
Molecular Mechanisms ◽  
Type I Collagen ◽  
Regulatory Elements ◽  
Transcriptional Level ◽  
Type I ◽  
Collagen Gene ◽  
Cis Acting ◽  
Collagen Gene Expression

Type I collagen, the major component of extracellular matrix in skin and other tissues, is a heterotrimer of two α1 and one α2 collagen polypeptides. The synthesis of both chains is highly regulated by different cytokines at the transcriptional level. Excessive synthesis and deposition of collagen in the dermal region causes thick and hard skin, a clinical manifestation of scleroderma. To better understand the causes of scleroderma or other tissue fibrosis, it is very Important to investigate the molecular mechanisms that cause upregulation of the Type I collagen synthesis in these tissues. Several cis-acting regulatory elements and trans-acting protein factors, which are involved in basal as well as cytokine-modulated Type I collagen gene expression, have been identified and characterized. Hypertranscription of Type I collagen in scleroderma skin fibroblasts may be due to abnormal activities of different positive or negative transcription factors In response to different abnormally induced signaling pathways. In this review, I discuss the present day understanding about the involvement of different factors in the regulation of basal as well as cytokine-modulated Type I collagen gene expression and its implication in scleroderma research.

scholarly journals A Novel Role of Annexin A2 in Human Type I Collagen Gene Expression

2015 ◽  
Vol 116 (3) ◽  
pp. 408-417 ◽  
Author(s):  
Georgia Schäfer ◽  
Jessica K. Hitchcock ◽  
Tamlyn M. Shaw ◽  
Arieh A. Katz ◽  
M. Iqbal Parker
Keyword(s):  
Gene Expression ◽  
Type I Collagen ◽  
Annexin A2 ◽  
Type I ◽  
Collagen Gene ◽  
Human Type ◽  
Collagen Gene Expression

scholarly journals Fibronectin binding site in type I collagen regulates fibronectin fibril formation.

1993 ◽  
Vol 121 (5) ◽  
pp. 1165-1172 ◽  
Author(s):  
B J Dzamba ◽  
H Wu ◽  
R Jaenisch ◽  
D M Peters
Keyword(s):  
Binding Site ◽  
Type I Collagen ◽  
Sparse Matrix ◽  
Type I ◽  
Collagen Gene ◽  
Wild Type ◽  
Binding Region ◽  
Fibronectin Binding ◽  
Fibronectin Fibrils

Mov13 fibroblasts, which do not express endogenous alpha 1(I) collagen chains due to a retroviral insertion, were used to study the role of type I collagen in the process of fibronectin fibrillogenesis. While Mov13 cells produced a sparse matrix containing short fibronectin fibrils, transfection with a wild type pro alpha 1(I) collagen gene resulted in the production of an extensive matrix containing fibronectin fibrils of normal length. To study the amino acids involved in the fibronectin-collagen interaction, mutations were introduced into the known fibronectin binding region of the pro alpha 1(I) collagen gene. Substitution of Gln and Ala at positions 774 and 777 of the alpha 1(I) chain for Pro resulted in the formation of short fibronectin fibrils similar to what was observed in untransfected Mov13 cells. Type I collagen carrying these substitutions bound weakly to fibronectin-sepharose and could be eluted off with 1 M urea. The effect of this mutation on fibronectin fibrillogenesis could be rescued by adding either type I collagen or a peptide fragment (CB.7) which contained the wild type fibronectin binding region of the alpha 1(I) chain to the cell culture. These results suggest that fibronectin fibrillogenesis in tissue culture is dependent on type I collagen synthesis, and define an important role for the fibronectin binding site in this process.

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