scholarly journals Dexamethasone modulates the metabolism of type IV collagen and fibronectin in human basement-membrane-forming fibrosarcoma (HT-1080) cells

1987 ◽  
Vol 245 (1) ◽  
pp. 235-241 ◽  
Author(s):  
A Oikarinen ◽  
T Salo ◽  
L Ala-Kokko ◽  
K Tryggvason
Keyword(s):  
Total Protein ◽  
Messenger Rna ◽  
Collagen Synthesis ◽  
Glucocorticoid Receptors ◽  
Type Iv Collagen ◽  
Cell Layer ◽  
Specific Binding ◽  
Specific Radioactivity ◽  
Filtration Method ◽  
Type Iv

The effect of dexamethasone on the synthesis and degradation of type IV collagen was studied in human fibrosarcoma cells, HT-1080. A dexamethasone concentration as low as 0.1 microM markedly increased collagen synthesis in HT-1080 cells labelled with [14C]proline. The increase in type IV collagen synthesis was not specific, since total protein synthesis was also increased. Further studies indicated that part of the increase was due to an increase in the specific radioactivity of the intracellular proline pool, after dexamethasone treatment. In fact, with dexamethasone concentrations of 0.1-10 microM the relative collagen synthesis was decreased, indicating that synthesis of other protein was increased more than that of type IV collagen. This was also confirmed by measuring the relative amount of type IV collagen RNA by using recombinant plasmid cDNA specific for the human procollagen pro alpha l (IV) RNA. The results indicated that relative collagen synthesis and the relative amount of type IV collagen messenger RNA was decreased similarly, indicating that dexamethasone affected type IV collagen synthesis at the pre-translational level. The dexamethasone-induced effect on total protein and collagen synthesis was maximal after 12-24 h. Dexamethasone induced a marked accumulation of collagen into the cell layer, leading to diminished deposition of soluble collagen into the medium. Since bacterial-collagenase treatment of the cell layer drastically decreased the collagen content of the dexamethasone-treated cells, this indicates that dexamethasone caused an accumulation of collagen into the extracellular matrix of the cell layer. In contrast, the amount of fibronectin was markedly increased in the medium. Dexamethasone decreased the type IV collagen-degrading activity in HT-1080 cells. The HT-1080 cells contained glucocorticoid receptors, as demonstrated by two different methods: by a whole-cell binding assay and by using a cytosol-gel-filtration method. The number of specific binding sites was similar to that in human skin fibroblasts. In conclusion, glucocorticoids affect the metabolism of type IV collagen and fibronectin in HT-1080 cells, and, since these cells contain specific glucocorticoid receptors, the effects are apparently receptor-mediated.

scholarly journals [3H]proline incorporation and hydroxyproline concentration in articular cartilage during the development of osteoarthritis caused by immobilization. A study in vivo with rabbits

1981 ◽  
Vol 200 (2) ◽  
pp. 435-440 ◽  
Author(s):  
T Videman ◽  
I Eronen ◽  
T Candolin
Keyword(s):  
Total Protein ◽  
Collagen Synthesis ◽  
Weight Bearing ◽  
Specific Radioactivity ◽  
Collagen Content ◽  
Synthetic Activity ◽  
Synthesis Rate ◽  
Hydroxyproline Concentration ◽  
Proline Incorporation

Proline metabolism in vivo was studied during the development of immobilization osteoarthritis in rabbits. Collagen content was measured as the hydroxyproline concentration of the tissue in question. The incorporation of [3H]proline was used as the indicator for total protein synthesis; collagen synthesis rate was estimated from measurements of the specific radioactivity of hydroxyproline. Cartilage samples from knee and hip joints were analysed after 3, 7, 11, 18, 35 and 56 days of immobilization. The total protein and collagen synthesis rates of the immobilized legs increased and reached a maximum after 11-35 days. Although they decreased thereafter, these rates remained elevated to the end of the experiment. A slight increase in the synthetic activity of the non-immobilized contralateral legs was also detected after 7--18 days of immobilization. The isotope incorporation was markedly higher in tibial marginal tissue than in weight-bearing cartilage. In spite of the increased synthesis, no clear changes were found in the collagen content of the tissues studied during the experiment.

Hypoxia and high glucose cause exaggerated mesangial cell growth and collagen synthesis: role of osteopontin

2001 ◽  
Vol 280 (4) ◽  
pp. F667-F674 ◽  
Author(s):  
Chhinder P. Sodhi ◽  
Sarojini A. Phadke ◽  
Daniel Batlle ◽  
Atul Sahai
Keyword(s):  
Cell Growth ◽  
High Glucose ◽  
Collagen Synthesis ◽  
Type Iv Collagen ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Neutralizing Antibody ◽  
Cell Number ◽  
Mrna Levels ◽  
Type Iv

The effect of hypoxia on the proliferation and collagen synthesis of cultured rat mesangial cells was examined under normal-glucose (NG, 5 mM) and high-glucose (HG, 25 mM)-media conditions. In addition, a role for osteopontin (OPN) in mediating these processes was assessed. Quiescent cultures were exposed to hypoxia (3% O2) and normoxia (18% O2) in a serum-free medium with NG or HG, and cell proliferation, collagen synthesis, and OPN expression were assessed. Cells exposed to hypoxia in NG medium resulted in significant increases in [3H]thymidine incorporation, cell number, and [3H]proline incorporation, respectively. HG incubations also produced significant stimulation of these parameters under normoxic conditions, which were markedly enhanced in cells exposed to hypoxia in HG medium. In addition, hypoxia and HG stimulated the mRNA levels of type IV collagen, and the combination of hypoxia and HG resulted in additive increases in type IV collagen expression. Hypoxia and HG also stimulated OPN mRNA and protein levels in an additive fashion. A neutralizing antibody to OPN or its β3-integrin receptor significantly blocked the effect of hypoxia and HG on proliferation and collagen synthesis. In conclusion, these results demonstrate for the first time that hypoxia in HG medium produces exaggerated mesangial cell growth and type IV collagen synthesis. In addition, OPN appears to play a role in mediating the accelerated mesangial cell growth and collagen synthesis found in a hyperglycemic and hypoxic environment.

Ascorbic acid phosphate stimulates type IV collagen synthesis and accelerates adipose conversion of 3T3-L1 cells

1990 ◽  
Vol 187 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Masaaki Ono ◽  
Yasuaki Aratani ◽  
Ikumi Kitagawa ◽  
Yasuo Kitagawa
Keyword(s):  
Ascorbic Acid ◽  
Collagen Synthesis ◽  
Type Iv Collagen ◽  
Acid Phosphate ◽  
Type Iv ◽  
Adipose Conversion

scholarly journals The contribution of increased collagen synthesis to human glomerulosclerosis: a quantitative analysis of alpha 2IV collagen mRNA expression by competitive polymerase chain reaction.

1992 ◽  
Vol 176 (6) ◽  
pp. 1571-1576 ◽  
Author(s):  
E P Peten ◽  
L J Striker ◽  
M A Carome ◽  
S J Elliott ◽  
C W Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Polymerase Chain Reaction ◽  
Reverse Transcription ◽  
Collagen Synthesis ◽  
Type Iv Collagen ◽  
Chain Reaction ◽  
Collagen Mrna ◽  
Type Iv ◽  
Polymerase Chain

We previously reported that one of the main components of the sclerotic material in human glomerular diseases was type IV collagen. In this study we examined the contribution of increased synthesis to this process at the gene expression level. Sufficient material has not been available to study type IV collagen synthesis by normal or sclerotic glomeruli in humans. We took advantage of the availability of nephrectomy specimens from patients with renal carcinoma, and of the observation that approximately 50% of these patients develop varying degrees of glomerulosclerosis. We microdissected glomeruli from 10 patients and analyzed them using in situ reverse transcription coupled with polymerase chain reaction (PCR) analyses (in situ RT-PCR). alpha 2IV collagen mRNA, after reverse transcription into cDNA, was detected in all patients and appeared to be increased in those with glomerulosclerosis (n = 5). A competitive PCR assay was developed to quantitate this change. There was an average 3.7-fold increase in glomerular type IV collagen cDNA in patients with significant sclerosis. This change was not due to an increased number of glomerular cells. Thus, glomerulosclerosis in humans is associated with an elevation of glomerular type IV collagen gene expression, suggesting that increased synthesis of type IV collagen may represent one component of this process.

Selective estrogen receptor modulators suppress mesangial cell collagen synthesis

2000 ◽  
Vol 279 (2) ◽  
pp. F309-F318 ◽  
Author(s):  
Joel Neugarten ◽  
Anjali Acharya ◽  
Jun Lei ◽  
Sharon Silbiger
Keyword(s):  
Estrogen Receptor ◽  
Collagen Synthesis ◽  
Type Iv Collagen ◽  
Mesangial Cell ◽  
Type I ◽  
Dependent Manner ◽  
Type Iv ◽  
Estrogen Receptor Modulators ◽  
Receptor Modulators ◽  
Dose Dependent

Estrogen receptor modulators (SERMs) are “designer drugs” that exert estrogen-like actions in some cells but not in others. We examined the effects of the SERMs LY-117018 (an analog of raloxifene) and tamoxifen on mesangial cells synthesis of type I and type IV collagen. We found that LY-117018 and tamoxifen suppressed mesangial cell type IV collagen gene transcription and type IV collagen protein synthesis in a dose-dependent manner, with a potency identical to that of estradiol. Type I collagen synthesis was also suppressed by LY-117018 in a dose-dependent manner with a potency identical to that of estradiol but greater than that of tamoxifen. Genistein, which selectively binds to estrogen receptor-β in nanomolar concentrations, suppressed type I and type IV collagen synthesis, suggesting that estrogen receptor-β mediates the effects of estrogen on collagen synthesis. Because matrix accumulation is central to the development of glomerulosclerosis, second-generation SERMs may prove clinically useful in ameliorating progressive renal disease without the adverse effects of estrogen on reproductive tissues.

scholarly journals Binding of laminin to type IV collagen: a morphological study.

1985 ◽  
Vol 100 (6) ◽  
pp. 1848-1853 ◽  
Author(s):  
A S Charonis ◽  
E C Tsilibary ◽  
P D Yurchenco ◽  
H Furthmayr
Keyword(s):  
Electron Microscopy ◽  
Morphological Study ◽  
Type Iv Collagen ◽  
Specific Binding ◽  
Terminal Region ◽  
The Other ◽  
Heat Denaturation ◽  
Type Iv ◽  
Nc1 Domain ◽  
Rotary Shadowing

A mixture of laminin and type IV collagen was analyzed by rotary shadowing using carbon/platinum and electron microscopy. Laminin was found to form distinct complexes with type IV collagen: one site of interaction is located 140 nm from the COOH-terminal, noncollagenous (NC1) domain and the other is located within the NH2-terminal region. The isolated NC1 fragment of type IV collagen does not appear to interact with laminin, while pepsin-treated type IV collagen, which lacks the NC1 domain, retains its ability to form complexes with laminin. Analysis of the laminin-type IV complexes indicates that laminin binds to type IV collagen via the globular regions of either of its four arms. This finding is supported by experiments using fragment P1 of laminin which lacks the globular regions and which does not bind to type IV collagen in a specific way. In addition, after heat-denaturation of laminin no specific binding is observed.

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