Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The skin of an anuran tadpole undergoes region-dependent metamorphic changes: the body (head and body trunk) transforms into the adult type, while the tail falls into programmed cell death. The present study was undertaken to investigate the regional specificity of metamorphosis at a molecular level, focusing on genes of collagen and collagenase that are known to be activated in their synthesis at metamorphosis. A cDNA probe utilized for collagen was Hf677 (a clone of human type I collagen alpha 1 chain). A probe for collagenase gene was cloned in the present study from a cDNA library of bullfrog tadpole skin, characterized and named Tc1. Tc1 contained the consensus sequence of zinc-metalloproteinases and showed a high homology to mammalian collagenases. Using these recombinant DNAs as probes, RNA blot analyses were performed for the body and tail skin of tadpoles that had been in spontaneous metamorphosis, induced to metamorphosis by the injection of thyroid hormone, or had been induced to grow by prolactin treatment. Collagenase gene was activated irrespective of regions of the skin, body or tail at the early metamorphic climax stage, although the extent of activation was region-dependent. In contrast, metamorphic changes of collagen gene expression showed a clear regional dependency. The transcription level in body skin was enhanced at the onset of metamorphosis while that in tail skin was markedly suppressed. Thyroid hormone was shown to be responsible for this region-dependent expression of collagen genes at metamorphosis. Prolactin, a suppressor hormone of amphibian metamorphosis, enhanced the transcription of collagen genes and suppressed that of collagenase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regionally and hormonally regulated expression of genes of collagen and collagenase in the anuran larval skin. 798 Oct 43

We have characterized the putative AP1 site in the backbone of pUC plasmids and found unique regulatory effects. The site, which mapped to a 19-bp region around nucleotide 37, conferred transcriptional activation by Jun or Jun/Fos that was boosted up to fivefold by unliganded thyroid hormone receptor (TR). Thyroid hormone changed potentiation of the Jun response by TR into repression. Although the plasmid sequence is a near-perfect consensus AP1 site, the perfect consensus AP1 site from the human collagenase promoter did not show the same effects. Deletion of the ligand binding domain of the TR eliminated the ability of the receptor to boost Jun activity, and deletion, mutation, or changes in specificity of the DNA binding domain eliminated both its ability to potentiate Jun activity and repress with hormone. In vitro Jun/Fos complexes bound the operative plasmid fragment, and the presence of TR interfered very little with Jun/Fos binding activity. Protein interaction studies in the absence of DNA showed that TR bound Jun protein in solution either in the presence or in the absence of hormone. These observations suggest a mechanism for synergy and repression by TR through modulation of Jun activity: positive when TR is unliganded, and negative when hormone is bound. They also suggest that the presence of the plasmid element can confound studies of the regulation of linked promoters.
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PMID:Positive and negative modulation of Jun action by thyroid hormone receptor at a unique AP1 site. 847 60

Epithelial properties of thyrocytes are difficult to maintain in conventional cell culture systems. We used bicameral chambers (Transwell) in attempts to establish a functional epithelium of thyrocytes of human origin. Thyroid follicle segments were isolated by collagenase digestion of paradenomatous tissue obtained at surgery for follicular adenoma and of tissue from glands with Graves' disease. After careful separation from connective tissue and single cells by centrifugation, the follicles were plated at high density on the collagen-coated filter of the chambers and cultured in Eagle's essential medium (EMEM) containing 10% fetal calf serum (FCS) or Coon's modified Hams medium enriched with five or six factors (5H, 6H); the latter media contained 5% FCS without (5H) or with (6H) thyrotropin (TSH). The follicles were converted into a confluent cell layer, which had similar DNA content irrespective of type of medium, after 4-6 days. Cells grown in EMEM or 5H established a transepithelial electrical resistance (R) of 200-500 omega.cm2 and was impermeable to [3H]inulin, indicating the formation of epithelial junctions. Addition of 6H to confluent cells initially cultured in EMEM or 5H caused a further increase of R, maximally to 1500 omega.cm2, along with a rise of the transepithelial potential difference; 6H promoted the monolayer formation of cells, increased the number of apical microvilli and reinforced the junctional distribution of actin, cadherin and ZO-1; 6H also enhanced the polarized secretion of [3H]leucine-labeled thyroglobulin into the apical medium. Cells from Graves' thyroid tissue established an epithelium on the filter with similar characteristics to that of normal thyrocytes; some platings contained in addition large numbers of HLA-DR positive cells with a dendritic shape. HLA-DR expression was generally absent in EMEM-or 5H-grown thyrocytes, but appeared in limited areas of the cell layer after 6H and was expressed by all epithelial cells after interferon-gamma stimulation for 48 h. We conclude that human thyrocytes form a tight and polarized epithelium when cultured on permeable filters. The polarized structure and function of the cells are positively regulated by TSH. The culture system may be useful in studies addressing the role of the epithelial phenotype (cell polarity and tight barrier) in normal thyroid function as well as in pathological processes in the thyroid, such as autoimmunity, cell transformation and tumor progression.
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PMID:Primary culture of human thyrocytes in Transwell bicameral chamber: thyrotropin promotes polarization and epithelial barrier function. 892 31

Nuclear receptors inhibit synthesis of collagenase-1 (matrix metalloproteinase-1; MMP-1), an enzyme that degrades interstitial collagens and contributes to joint pathology in rheumatoid arthritis. SMRT (Silencing Mediator for Retinoid and Thyroid hormone receptors) mediates the repressive effect of nuclear receptors at hormone responsive elements (HREs), prompting us to investigate whether this co-repressor could also regulate transcription of MMP-1, which lacks any known HREs. We find that primary synovial fibroblasts express SMRT. When over-expressed by transient transfection, SMRT inhibits MMP-1 promoter activity induced by interleukin-1 (IL-1), phorbol phorbol myristate acetate (PMA) or v-Src. SMRT apparently inhibits MMP-1 gene expression by interfering with one or more transcriptional elements clustered in a region between -321 and +63. We conclude that SMRT negatively regulates MMP-1 synthesis through a novel, HRE-independent mechanism that involves proximal regions of the MMP-1 promoter.
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PMID:The nuclear receptor corepressor SMRT inhibits interstitial collagenase (MMP-1) transcription through an HRE-independent mechanism. 926 28

Stimulation of growth of endothelial cells from preexisting blood vessels, i.e., angiogenesis, is one of the essential elements necessary to create a permissive environment in which a tumor can grow. During angiogenesis, the matrix metalloproteinase (MMP) family of tissue enzymes contributes to normal (embriogenesis or wound repair) and pathologic tissue remodeling (chronic inflammation and tumor genesis). The proposed pathogenic roles of MMPs in cancer are tissue breakdown and remodeling during invasive tumor growth and tumor angiogenesis. Tissue inhibitors of metalloproteinases (TIMPs) form a complex with MMPs, which in turn inhibits active MMPs. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are unique among mediators of angiogenesis with synergistic effect, and both can also be secreted by thyroid cancer cells. The goal of the study was to evaluate the plasma blood concentration of VEGF, bFGF, MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, TIMP-1, and TIMP-2 in patients with cancer and in normal subjects. Twenty-two patients with thyroid cancers (papillary cancer, 11; partly papillary and partly follicular cancer, 3; anaplastic cancer, 5; medullary cancer, 3) and 16 healthy subjects (controls) were included in the study. VEGF, bFGF MMPs, and TIMPs were evaluated by enzyme-linked immunosorbent assay (ELISA). In patients with thyroid cancer, normal VEGF concentrations (74.29 +/- 13.38 vs. 84.85 +/- 21.71 pg/mL; p > 0.05) and increased bFGF (29.52 +/- 4.99 vs. 6.05 +/- 1.43 pg/mL; p < 0.001), MMP-2 (605.95 +/- 81.83 vs. 148.75 +/- 43.53 ng/mL; p < 0.001), TIMP-2 (114.19 +/- 6.62 vs. 60.75 +/- 9.18 ng/mL; p < 0.001), as well as lower MMP-1 (0.70 +/- 0.42 vs. 3.87 +/- 0.53; p < 0.001) levels have been noted. Increased plasma levels of MMP-3 and MMP-9 were also found in patients with medullary carcinoma. In conclusion, predominance of MMP-2 over TIMP-2 and TIMP-1 over MMP-1 as well as increased concentration of bFGF in peripheral blood are common features in patients with thyroid cancer.
Thyroid 2002 Aug
PMID:Matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases and angiogenic cytokines in peripheral blood of patients with thyroid cancer. 1222 33

From collagenase digests of human thyroid, endothelial cells were separated from follicular cells by their greater adherence to gelatin-coated plates. Endothelial cells were further purified using fluorescence-activated cell sorting, selecting for cells expressing factor VIII-related antigen. Isolated cells were negative for thyroglobulin and calcitonin when examined by immunostaining. The receptor for the angiopoietins, Tie-2, was expressed by the cells, and expression was increased by agents that elevate cAMP. Nitric oxide synthase (NOS) 3, the endothelial form of NOS, was expressed by the cells and similarly regulated. Cells responded strongly to the mitogen fibroblast growth factor (FGF)-2 in growth assays but only weakly to vascular endothelial growth factor (VEGF). VEGF was, however, able to stimulate nitric oxide release from the cells consistent with their endothelial origin. The FGF receptor (FGFR1) was full length (120 kDa) and immunolocalized to the cytosol and nucleus. Thyrotropin (TSH) did not regulate FGFR1, but its expression was increased by VEGF. Thrombospondin, a product of follicular cells, was a growth inhibitor, but neither TSH nor 3,5,3'-triiodothyronine had direct mitogenic effects. Thyroid follicular cell conditioned medium contained plasminogen activator activity and stimulated the growth of the endothelial cells, but when treated with plasminogen to produce the endothelial-specific inhibitor, angiostatin, growth was inhibited. Human thyroid endothelial cell cultures will be invaluable in determining the cross talk between endothelial and follicular cells during goitrogenesis.
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PMID:Isolation and characterization of human thyroid endothelial cells. 1962 78

In the present study we investigated, by means of zymography and reverse transcription-polymerase chain reaction (RT-PCR), the expression of different matrix metalloproteinases (MMPs) and of the specific tissue inhibitor of metalloproteinases [TIMPs] in human cell lines derived from normal thyrocytes (HTU5), follicular adenoma (HTU42), and follicular (FTC-133), papillary (B-CPAP), and anaplastic (CAL-62, 8305C) thyroid carcinomas. We demonstrated that normal thyrocytes constitutively express MMP-1, MMP-2, MMP-10, MMP-14, and TIMP-1, TIMP-2, TIMP-3, and TIMP-4, and this pattern of expression is profoundly modified in all thyroid tumor-derived cell lines. Analysis of the gelatinolytic activity in the different cell supernatants showed that the expressions of MMP-2 and MMP-9 are, respectively, increased or induced in all the neoplastic cell lines, except in CAL-62. Caseinolytic activity was found only in the supernatants of the 8305C and B-CPAP cells. Using RTPCR analysis we detected an increased expression of MMP-1 in cell lines derived from papillary and from one (8305C) of the two anaplastic carcinomas. MMP-13 mRNA was expressed only in the 8305C, FTC-133, and BCPAP cells. Among stromelysins, MMP-3 mRNA could not be detected in any cell line, while MMP-10 mRNA was expressed in all of them, although at variable levels. MMP-11 mRNA was absent in normal and follicular adenoma derived thyrocytes and induced in all carcinoma cell types. The expression of MMP-14 (MT1-MMP) mRNA was found significantly increased in all thyroid tumor cell lines with respect to HTU5 and HTU42 cells. The expression of TIMP-1 and TIMP-2 mRNAs was maintained in all cell lines tested, while that of TIMP-3 was lost in both anaplastic carcinoma cell lines and that of TIMP-4 was absent in the CAL-62. In conclusion, our data demonstrated a differential expression of MMPs and TIMPs in different thyroid tumor cell types with respect to normal thyrocytes. In particular, the induction of MMP-11 in all thyroid-derived carcinoma cell lines studied and of MMP-13 in all but one may represent, if confirmed in other thyroid tumor-derived cell lines and in thyroid tumor tissues, a new marker of thyrocyte transformation.
Thyroid 2004 Nov
PMID:Expression of matrix metalloproteinases and their specific inhibitors in normal and different human thyroid tumor cell lines. 1567 65

Usually thyroid cells isolated from tissue obtained by surgery or thyroid cell lines are used to investigate the pathogenesis of autoimmune thyroid diseases. Isolation and cultivation of thyrocytes from fine-needle aspiration biopsy (FNAB) has not yet been published. The aim of this study was to isolate and cultivate thyrocytes from samples of FNAB. FNAB samples were obtained from nine adults and nine children with Hashimoto's thyroiditis (HT). The aspiration material was filtered resulting in small samples of tissue on the surface of the filter membrane. These tissue fragments were digested by collagenase I and dispase II. The yielding cells were cultivated for 3 weeks in Ham's F12 Kaighn's Modification medium in presence of 1 mU/mL bovine thyrotropin (TSH), 10 microg/mL human insulin, 6 microg/mL transferrin, and 10(-8) M hydrocortisone. Finally, isolated thyroid cells were characterized by determination of gene expression of thyrotropin receptor (TSHR), thyroperoxidase (TPO), and thyroglobulin (Tg) using a nested reverse transcriptase-polymerase chain reaction (RT-PCR). Thyroid cells obtained by FNAB can be maintained over a time period of approximately 3 weeks. Depending on the sample size a final number of 1000-14,000 cells was gained per FNAB. In addition, all cells isolated by the described method expressed TPO mRNA. TSHR mRNA was found in 4 samples, whereas 15 samples were Tg mRNA-positive. There were no differences with respect to the expression TSHR and TPO mRNA between samples from adults and children. The isolation and cultivation of thyroid cells obtained by FNAB has been established. In contrast to surgical specimen, this technique provides an easy access to thyrocytes derived from individual patients allowing repeated sampling to investigate the time progression of the chronic disease or the effect of treatment over time.
Thyroid 2005 Sep
PMID:Isolation of thyroid cells obtained by fine-needle aspiration biopsy. 1618 6


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