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Collagen Gene Expression (collagen + gene_expression)
Selected AbstractsCollagen gene expression and mechanical properties of intervertebral disc cell,alginate culturesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2001Anthony E. Baer Cells of the intervertebral disc have a limited capacity for matrix repair that may contribute to the onset and progression of degenerative disc changes. In this study, the biosynthetic capacity of cells isolated from specific regions of the porcine intervertebral disc was evaluated in vitro. Using a competitive reverse transcription-polymerase chain reaction technique, gene expression levels for types I and II collagen were quantified in cells cultured for up to 21 d in a three-dimensional alginate culture system and compared to levels obtained for cells in vivo. The mechanical properties of cell-alginate constructs were measured in compression and shear after periods of culture up to 16 weeks. Cells from the anulus fibrosus expressed the most type I collagen mRNA in vivo and in vitro, while cells from the transition zone expressed the most type II collagen mRNA in vivo and in vitro. Mechanical testing results indicate that a mechanically functional matrix did not form at any time during the culture period; rather, decreases of up to 50% were observed in the compressive and shear moduli of the cell,alginate constructs compared to alginate with no cells. Together with results of prior studies, these results suggest that intervertebral disc cells maintain characteristics of their phenotype when cultured in alginate, but the molecules they synthesize are not able to form a mechanically functional matrix in vitro. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] MicroRNA-29, a key regulator of collagen expression in systemic sclerosisARTHRITIS & RHEUMATISM, Issue 6 2010Britta Maurer Objective To investigate the role of microRNA (miRNA) as posttranscriptional regulators of profibrotic genes in systemic sclerosis (SSc). Methods MicroRNA, which target collagens, were identified by in silico analysis. Expression of miRNA-29 (miR-29) was determined by TaqMan real-time polymerase chain reaction analysis of skin biopsy and fibroblast samples from SSc patients and healthy controls as well as in the mouse model of bleomycin-induced skin fibrosis. Cells were transfected with precursor miRNA (pre-miRNA)/anti-miRNA of miR-29 using Lipofectamine. Collagen gene expression was also studied in luciferase reporter gene assays. For stimulation, recombinant transforming growth factor , (TGF,), platelet-derived growth factor B (PDGF-B), or interleukin-4 (IL-4) was used. The effects of inhibiting PDGF-B and TGF, signaling on the levels of miR-29 were studied in vitro and in the bleomycin model. Results We found that miR-29a was strongly down-regulated in SSc fibroblasts and skin sections as compared with the healthy controls. Overexpression in SSc fibroblasts significantly decreased, and accordingly, knockdown in normal fibroblasts increased, the levels of messenger RNA and protein for type I and type III collagen. In the reporter gene assay, cotransfection with pre-miR-29a significantly decreased the relative luciferase activity, which suggests a direct regulation of collagen by miR-29a. TGF,, PDGF-B, or IL-4 reduced the levels of miR-29a in normal fibroblasts to those seen in SSc fibroblasts. Similar to human SSc, the expression of miR-29a was reduced in the bleomycin model of skin fibrosis. Inhibition of PDGF-B and TGF, pathways by treatment with imatinib restored the levels of miR-29a in vitro and in the bleomycin model in vivo. Conclusion These data add the posttranscriptional regulation of collagens by miR-29a as a novel aspect to the fibrogenesis of SSc and suggest miR-29a as a potential therapeutic target. [source] Glycolic Acid Treatment Increases Type I Collagen mRNA and Hyaluronic Acid Content of Human SkinDERMATOLOGIC SURGERY, Issue 5 2001Eric F. Bernstein MD Background. Chronic solar irradiation results in both morphologic and functional changes in affected skin. ,-hydroxy acids, such as glycolic acid, have been shown to improve photodamaged skin. Objective. To investigate alterations in collagen gene induction and epidermal and dermal hyaluronic acid production as a result of administered glycolic acid. Methods. In this study we compared collagen gene expression from skin biopsy specimens, and epidermal and dermal hyaluronic acid immunohistochemical staining between glycolic acid-treated and vehicle-treated skin. Forearm skin was treated with 20% glycolic acid lotion or a lotion vehicle control twice a day for 3 months. Results. Epidermal and dermal hyaluronic acid and collagen gene expression were all increased in glycolic acid-treated skin as compared to vehicle-treated controls. Conclusion. Our data suggest that epidermal and dermal remodeling of the extracellular matrix results from glycolic acid treatment. Longer treatment intervals may result in collagen deposition as suggested by the measured increase in mRNA. [source] Quantitative analysis of the synthesis and secretion of type VII collagen in cultured human dermal fibroblasts with a sensitive sandwich enzyme-linked immunoassayEXPERIMENTAL DERMATOLOGY, Issue 2 2007Satoshi Amano Abstract:, Type VII collagen is the major component of anchoring fibrils in the epidermal basement membrane. Its expression has been analyzed by immunostaining or Northern blotting, but rarely at the protein level. In this study, we have quantitatively examined the effects of ascorbic acid and various cytokines/growth factors on the protein synthesis and secretion of type VII collagen by human dermal fibroblasts in culture, using a developed, highly sensitive sandwich enzyme-linked immunoassay with two kinds of specific monoclonal antibodies against the non-collagenous domain-1. Ascorbic acid and its derivative induced a twofold increase in type VII collagen synthesis, and markedly increased the secretion of type VII collagen into the medium when compared with the control culture. This effect was not influenced by the presence of transforming growth factor- ,1 (TGF- ,1). The synthesis of type VII collagen was elevated by TGF- ,1, platelet-derived growth factor, tumor necrosis factor- ,, and interleukin-1,, but not by TGF- ,. Thus, our data indicate that the synthesis and secretion of type VII collagen in human dermal fibroblasts are regulated by ascorbate and the enhancement of type VII collagen gene expression by cytokines/growth factors is accompanied with elevated production of type VII collagen at the protein level. [source] From collagen chemistry towards cell therapy , a personal journeyINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2007Michael E. Grant Summary The Fell,Muir Award requires the recipient to deliver a lecture and a review manuscript which provides a personal overview of significant scientific developments in the field of matrix biology over the period of the recipient's career. In this context, this review considers the collagen family of structural proteins and the advances in biochemical, molecular biological and genetic techniques which led to the elucidation of the structure, synthesis and function of this important group of extracellular matrix constituents. Particular attention is focussed on early research on the identification and assembly of the soluble precursors of collagen types I and II, and the identification of the precursor of basement membrane collagen type IV. In subsequent studies investigating the maintenance of the chick chondrocyte phenotype in culture, the influence of the extracellular milieu was found to influence markedly both cell morphology and collagen gene expression. These studies led to the discovery of collagen type X whose expression is restricted to hypertrophic chondrocytes at sites of endochondral ossification. Such research provided a prelude to investigations of mammalian endochondral ossification which is known to be aberrant in a variety of human chondrodysplasias and is reactivated in bone fracture repair and in osteoarthritis. The cloning of bovine and then human collagen type X genes facilitated studies in relevant human diseases and contributed to the discovery of mutations in the COL10A1 gene in families with metaphyseal chondrodysplasia type Schmid. Clustering of mutations in the C-terminal domain of the type X collagen molecule has now been widely documented and investigations of the pathogenic mechanisms in animal models are beginning to suggest the prospect of novel treatment strategies. [source] Down-Regulation of Procollagen ,1[I] Messenger RNA by Titanium Particles Correlates with Nuclear Factor ,B (NF-,B) Activation and Increased Rel A and NF-,B1 Binding to the Collagen PromoterJOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2001Kenneth A. Roebuck Abstract Previously, we showed that exposure of human osteoblasts to titanium particles stimulates protein tyrosine phosphorylation (PTP), activates the transcription factor nuclear factor ,B (NF-,B), and causes an approximately 50% decrease in the steady-state messenger RNA (mRNA) level of procollagen ,1[I]. In this study, we identify three NF-,B binding sites within the human procollagen ,1[I] gene promoter, show that titanium particles stimulate their binding of the NF-,B subunits Rel A (p65) and NF-,B1 (p50), and find NF-,B activation correlates with collagen gene suppression by titanium particles in osteoblasts. Protein tyrosine kinase (PTK) inhibitors, which significantly reduce the suppressive effect of titanium particles on collagen gene expression, inhibited NF-,B binding activity showing that titanium particle stimulation of PTK signals in osteoblasts are critical for both NF-,B activation and collagen gene expression. The antioxidant pyrrolidine dithiocarbamate (PDTC), which also inhibits the titanium particle suppression of collagen, abrogated the titanium particle activation of NF-,B, suggesting the involvement of redox signals in NF-,B-mediated collagen gene expression. The RNA polymerase II inhibitor actinomycin D (Act D) decreased procollagen ,1[I] mRNA expression and effectively blocked the titanium-induced suppressive effect, suggesting that titanium particles activate a cascade of signals in osteoblasts, which result in a suppression of procollagen ,1[I] mRNA. Collectively, these results show that titanium particles can activate NF-,B signaling in osteoblasts and suggest that NF-,B binding to the collagen gene promoter has a functional role in the down-regulation of procollagen ,1[I] gene transcription. [source] Effects of antisense oligodeoxynucleotide to type I collagen gene on hypertrophic scars in the transplanted nude mouse modelJOURNAL OF CUTANEOUS PATHOLOGY, Issue 11 2009Julin Xie Background:, Antisense nucleic acids are effective in inhibiting harmful or uncontrolled gene expression. We had previously proved that the antisense DNA to type I collagen could effectively inhibit the synthesis of collagen type I in cultured hypertrophic scar fibroblasts, suggesting a potential role in anti-scarring, but there are no published reports of its effect on scar in the transplanted nude mouse model. Aims:, To investigate the effects of antisense oligodeoxynucleotide (ASODN) to type I collagen gene on hypertrophic scars in the transplanted nude mouse model and clarify the potential of ASODN for the treatment of scars. Methods:, The nude mouse model of hypertrophic scar was created and subjected to daily injections with ASODN and LipofectamineÔ for 2 ,4 or 6 weeks. We then examined the scars for changes in histopathological characteristics. The effects of ASODN on type I collagen gene expression were examined by reverse transcription-polymerase chain reaction and Western blots. Results:, The ASODN could remarkably alleviate the scar in the nude mouse model and consistently inhibit type I collagen gene expression at both the mRNA and protein levels. Conclusion:, ASODN was effective in downregulating type I collagen gene expression and could prove to be useful in the treatment of scars. [source] Involvement of reactive oxygen species and nitric oxide radicals in activation and proliferation of rat hepatic stellate cellsLIVER INTERNATIONAL, Issue 1 2001Gianluca Svegliati-Baroni Abstract:Background /Aims: Reactive oxygen species (ROS) induce HSCs activation, proliferation and collagen gene expression in vitro. Nitric oxide (NO) represents a reactive molecule that reacts with ROS, yielding peroxynitrite. We thus verified the effect of NO on ROS-induced HSCs proliferation in vitro and correlated iNOS expression and ROS formation to HSCs activation in the early phase of liver injury leading to hepatic fibrosis in vivo. Methods/Results: HSCs were incubated with iron ascorbate (FeAsc) in vitro, which induced ROS production, ERK1/2 phosphorylation and increased cell proliferation. This effect was significantly reduced by the presence of the NO donor S-nitroso-N-acetylpenicillamine. Liver injury was induced in vivo in rats by dimethylnitrosamine administration. HSCs activation started 6 h after DMN administration and peaked at 1 week. ROS generation and neutrophil infiltration were evident for at least 48 h after DMN treatment, showing an identical distribution pattern. Only a few inflammatory cells expressed iNOS 6 h after DMN administration. Conclusions: we have shown that NO acts as a ROS scavenger in vitro, thus inhibiting HSCs proliferation. ROS production by infiltrating neutrophils occurs in the early phase of liver fibrosis and can represent a stimulus to HSCs activation in vivo. The reduced iNOS expression may account for the low NO levels and the inability to prevent the ROS-induced HSC activation in vivo. [source] Halofuginone inhibition of COL1A2 promoter activity via a c-Jun,dependent mechanismARTHRITIS & RHEUMATISM, Issue 10 2002Tracy L. McGaha Objective The naturally occurring compound halofuginone has been shown to antagonize collagen synthesis by fibroblasts both in vitro and in vivo. We previously demonstrated that this inhibitory property was related to the ability of halofuginone to disrupt transforming growth factor , signal transduction. The present study further analyzed the ability of halofuginone to affect transcription factors that can regulate type I collagen gene expression by examining its effect on c-Jun, the negative regulator of collagen gene transcription. Methods The phosphorylation state of c-Jun in the presence of halofuginone was examined via direct Western blotting, and the transcriptional activity of the activator protein 1 (AP-1) binding element via electrophoretic mobility shift assay and luciferase reporter assay. We determined whether the effect of halofuginone on collagen synthesis was dependent on the presence of c-Jun by ectopic expression of a wild-type or dominant-negative c-Jun construct in the presence of halofuginone and assaying ,2(I) collagen promoter strength via luciferase reporter assay. The effect of halofuginone on ,2(I) collagen message levels in fibroblasts when wild-type or dominant-negative c-Jun was overexpressed was determined. We also determined whether halofuginone had an effect on the phosphorylation state of c-Jun in the skin of TSK/+ mice via immunohistochemistry. Results Treatment of fibroblasts with 10,8M halofuginone enhanced basal and mitogen-mediated phosphorylation of c-Jun in culture. This elevated phosphorylation of c-Jun correlated with enhanced DNA binding and transcriptional activation of an AP-1 complex consisting of c-Jun and Fos but lacking the c-Jun antagonist JunB. Overexpression of c-Jun enhanced in a dose-dependent manner the ability of halofuginone to inhibit the activity of a luciferase reporter construct under control of the ,3200-bp to +54-bp COL1A2 promoter, whereas the expression of a dominant-negative c-Jun construct abolished this effect. Northern blotting showed that overexpression of c-Jun enhanced the ability of halofuginone to reduce collagen ,2(I) messenger RNA levels in fibroblasts, whereas expression of the dominant-negative c-Jun abolished this effect. Topical administration of a halofuginone-containing cream for 20 days to TSK mice, which spontaneously develop dermal fibrosis, greatly increased the phosphorylated form of c-Jun in the skin; this was followed by a decrease in skin thickness and type I collagen messenger RNA expression. Conclusion Our findings illustrate the powerful down-regulatory property of c-Jun toward type I collagen and establish that halofuginone exerts its effect on collagen synthesis in a c-Jun,dependent manner. [source] | ||||||||||