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)

Previous studies of human thyroid cells in culture (mostly from pathological tissues) failed to demonstrate a mitogenic effect of TSH, leading to the proposal that the growth effect of TSH in vivo might be indirect. To reexamine the influence of TSH on DNA synthesis and cell proliferation, we established primary cultures of normal thyroid tissue from nine subjects. When seeded in a 1% serum-supplemented medium, thyroid follicles released by collagenase/dispase digestion developed as a cell monolayer that responded to TSH by rounding up and by cytoplasmic retraction. When seeded in serum-free medium, the cells remained associated in dense aggregates surrounded by few slowly spreading cells. In the latter condition, the cells responded to TSH and other stimulators of cAMP production, such as cholera toxin and forskolin, by displaying very high iodide-trapping levels. Exposure to serum irreversibly abolished this differentiated function. TSH stimulated the proliferation (as shown by DNA content per culture dish) of 1% serum cultured cells (doubling times were reduced from 106 to 76 h) and increased by 100% the [3H]thymidine labeling indices. In serum-free cultured cells (dense aggregates or cell monolayers after initial seeding with serum), control levels of DNA synthesis were lower, and up to 8-fold stimulation of DNA synthesis occurred in response to 100 mU/L TSH (stimulation was consistently detected with 20 mU/L), based on measurements of [3H]thymidine incorporation into acid-precipitable material and counts of labeled nuclei on autoradiographs (up to 40% labeled nuclei within 24 h). The mitogenic effect of TSH required a high insulin concentration (8.3 X 10(-7) mol/L) or a low insulin-like growth factor I concentration. The mitogenic effects of TSH were mimicked in part by cholera toxin, forskolin, and dibutyryl cAMP. Epidermal growth factor and phorbol myristate ester also stimulated thyroid cell proliferation and DNA synthesis, but they potently inhibited TSH-stimulated iodide transport. We conclude that TSH, acting at least in part through cAMP, is a potent growth factor for human thyroid cells and thus provide an experimental basis in vitro for the well established in vivo goitrogenic action of TSH.
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PMID:Mitogenic effects of thyrotropin and adenosine 3',5'-monophosphate in differentiated normal human thyroid cells in vitro. 283 70

Platelet-derived growth factor (PDGF) in vitro stimulates DNA synthesis and chemotaxis of fibroblasts and smooth muscle cells and stimulates collagen, glycosaminoglycan, and collagenase production by fibroblasts. These in vitro properties suggest that PDGF, delivered by platelets to the site of injury in vivo, may play an important role in the initiation of the wound repair process. Studies presented here show that the addition of pure PDGF to a wound site involving the epidermis and dermis has little effect on the morphology or biochemistry of the healing wound. In contrast, the addition of partially purified PDGF resulted in significant dose-dependent increases in the width of the newly synthesized connective tissue and epidermal layers. Autoradiography using [3H]thymidine revealed increased numbers of labeled cells in the new connective tissue and epithelial layers. Furthermore, addition of partially purified PDGF resulted in significant increases in the rate of protein and DNA synthesis and the total content of these components in biopsies taken from the wound site. Similar effects were obtained when insulin-like growth factor I was added in combination with pure PDGF. This combination of factors caused a 2.4-fold increase in the width of the newly formed connective tissue layer and a 95% increase in epidermal thickness compared with controls. Insulin-like growth factor I alone caused no significant morphologic changes. Epidermal growth factor alone or in combination with PDGF resulted in a thickening only of the epidermis. These results indicate that the synergistic actions of other factors with PDGF are important in the modulation of the wound healing process.
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PMID:Role of platelet-derived growth factor in wound healing: synergistic effects with other growth factors. 349 12

We have investigated the proliferative responses of rat thyroid follicular cells in serum-free culture to a range of growth factors including TSH, epidermal growth factor, and insulin, added singly or in combination. Follicles released from normal thyroids by collagenase/dispase digestion were cultured in suspension in agarose-coated microtiter plates to prevent monolayer formation. Growth responses were measured by [3H] thymidine incorporation and by autoradiography over successive 24- or 36-h periods. Insulin, even in the absence of other growth factors, stimulated [3H]thymidine incorporation in a concentration-dependent manner, rising from basal levels of 486 +/- (SE) 18 cpm to 4222 +/- 367 cpm/5 X 10(4) cells at 8 micrograms/ml. In contrast, TSH alone had no effect. In the presence of threshold levels (0.08 micrograms/ml) of insulin, however, there was a highly significant (P less than 0.001) response to TSH, [3H]thymidine incorporation rising from 1089 +/- 163 cpm in the absence of TSH to a maximum of 7548 +/- 585 with 1 mU/ml TSH. There was a synergistic interaction between insulin and TSH over the concentrations tested. Epidermal growth factor either alone or in combination with insulin failed to produce a significant response. Parallel autoradiographic studies were concordant with the [3H]thymidine incorporation data. We conclude that whereas in the absence of other growth factors TSH is unable to stimulate DNA synthesis in isolated rat thyroid follicles, the inclusion of just a single growth factor, insulin, permits a marked response. These observations emphasize the need for inclusion of appropriate permissive growth factor(s) when assessing the in vitro effect of a suspected tissue-specific mitogen.
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PMID:Growth factor control of rat thyroid follicular cell proliferation. 353 Jul 18

Epidermal growth factor (EGF) regulates pancreatic acinar enzyme secretion. The mechanism of action of EGF in pancreatic acinar cells is not clear. In the present study we investigated the role of heterotrimeric GTP-binding proteins (G proteins) in EGF receptor signal transduction. Pancreatic acini were isolated from rat pancreas by collagenase digestion and permeabilized by digitonin. Activation of phosphatidylinositol 4,5-bisphosphate-specific phospholipase C (PLC) was assessed using a radioreceptor assay specific for inositol 1,4,5-trisphosphate [IP3(1,4,5)]. For measurement of amylase secretion isolated pancreatic acini were incubated with secretagogues for 30 min at 37 degrees C. Amylase released into the medium was assessed by monitoring the hydrolysis rate of p-nitrophenyl-alpha,D-maltohepatoside. The weakly hydrolyzable GTP analogue guanosine 5'-[3-O-thio]triphosphate (GTP gamma S) and guanosine 5'-diphosphate (GDP) were used to activate and inhibit G protein-mediated signal transduction, respectively. EGF (90 nM) stimulated amylase release in isolated pancreatic acini. This effect was enhanced by guanosine 5'-[3-O-thio]triphosphate (0.1 mM), which stimulates G proteins. Guanosine 5'-diphosphate (1 mM), which inhibits the activity of heterotrimeric G proteins, had no effect on basal and EGF-induced amylase release. Lower EGF concentrations (20 nM) inhibited COOH-terminal cholecystokinin octapeptide (CCK8)-induced IP3(1,4,5) production and amylase release in pancreatic acini). However, in the presence of GDP, EGF had no significant effect on CCK8-stimulated amylase release. Furthermore, coincubation of the acini with CCK8, EGF, and GDP revealed that GDP reduces the inhibitory effect of EGF on CCK8-induced IP3(1,4,5) production.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Epidermal growth factor receptor signaling in rat pancreatic acinar cells. 754 69

The aim of the study was to determine the binding characteristics of the epidermal growth factor (EGF) receptor in isolated human endometrial glands and stromal cells in culture. Stromal cells and glands were obtained from endometrial tissue by collagenase dispersion followed by sieve filtration. They were plated into 24-well multiwell plates in Ham's F10 medium supplemented with 5% fetal calf serum and used at 70-80% confluence. Scatchard analysis revealed a single class of high-affinity binding sites in both cell types with apparent dissociation constants of 1.17 +/- 0.6 (n = 15) and 1.20 +/- 0.3 (n = 8) nmol 1-1 for stromal cells and glands, respectively. The concentration of receptors was higher in stromal cells than in glands, 719 +/- 377 (n = 16) and 310 +/- 177 (n = 8) fmol mg-1 protein, respectively. Epidermal growth factor labelled with 125I was displaced from the receptor by EGF and transforming growth factor alpha, but not insulin, insulin-like growth factor, fibroblast growth factor, or platelet-derived growth factor. Binding was shown to be dependent on time and temperature. Downregulation of the receptor was demonstrated by preincubating cells with 5 nmol EGF I-1, which reduced receptor concentrations by 75%. 12-O-Tetradecanoylphorbol-13-acetate decreased the affinity of the receptor for EGF changing the dissociation constant from 1.8 to 3.9 nmol l-1. A suitable system for investigating the regulation of this receptor in human endometrium was established.
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PMID:Characterization of epidermal growth factor receptor in human endometrial cells in culture. 793 77

This study examined the effects of an epithelial and a mesenchymal growth factor on pleural mesothelial cell proliferation and collagen synthesis, functions that may be important in the response of the pleura to injury. Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) added singly caused significant increases relative to control in both the uptake of [3H]thymidine into the cellular DNA of subconfluent monolayers and of [3H]proline into collagenase-sensitive protein. Combinations of EGF and PDGF resulted in more than additive increases in proliferation and additive increases in collagen production relative to each factor alone. Media from control and growth factor-stimulated PMC demonstrated no gelatinase or collagenase activity, suggesting that the increase in net collagen production was secondary to enhanced synthesis. These data demonstrate that both epithelial and mesenchymal growth factors can stimulate PMC proliferation and collagen synthesis and that these growth factors have even greater effects when combined, particularly in regard to cellular proliferation. Increases in PMC proliferation and collagen synthesis in response to these growth factors may be important in healing the pleura after injury by a variety of disease processes.
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PMID:Growth factor modulation of rat pleural mesothelial cell mitogenesis and collagen synthesis. Effects of epidermal growth factor and platelet-derived factor. 820 47

Human surface respiratory epithelial (HSRE) cells from nasal polyps have been cultured within collagen lattices in a serum-free defined medium. Cell growth observed over a period of 12 days showed a population doubling time of 36 h. Under these culture conditions, we observed a contraction of the lattices. Phase-contrast light microscopy and transmission electron microscopy demonstrated that the HSRE cells formed tubular ductlike structures. Lumens formed by HSRE cells were surrounded by cuboidal-shaped polarized cells with numerous ciliated cells, secretory cells, and undifferentiated cells. Epidermal growth factor (EGF) was observed to stimulate the tubule formation and the contraction of the lattices. Videomicroscopic observations and analysis of the ciliary beating frequency (CBF) demonstrated that the cilia were homogeneously distributed on the whole apical surface of the ciliated cells and that their movement was well coordinated, with a CBF similar to that observed in outgrowth cells from cultured human nasal and tracheal epithelia. Immunofluorescent staining of basement membrane components synthesized and secreted by cells revealed the presence of type III collagen around the tubules. Type IV collagen and laminin were present in the cytoplasm and at the periphery of the cells. The biotin-streptavidin-gold immunocytochemical technique with monoclonal anti-mucin antibody showed intracellular localization of mucins in secretory granules of the secretory cells. With the use of substrate gel electrophoresis polyacrylamide gels impregnated with gelatin, collagenase activity was detected in the conditioned medium of the cultured HSRE cells. These results suggest that both three-dimensional collagen gel and soluble factors such as EGF regulate tubule formation by HSRE cells. Moreover, the capacity of the epithelial cells to contract the gel suggests they may be involved in the wound healing process.
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PMID:Tubule formation by human surface respiratory epithelial cells cultured in a three-dimensional collagen lattice. 844 30

Cultured cells from the bovine endosalpinx were used to evaluate effects of estradiol-17 beta, progesterone, epidermal growth factor, and insulinlike growth factors I and II on [3H]thymidine incorporation. Cells were treated with hormones and growth factors when approximately 50% confluent. After 24 h, DNA synthesis was quantified by pulsing cells with [3H]thymidine for 12 h and determining uptake into DNA. Cells prepared by mechanical dispersal incorporated more [3H]thymidine than cells dispersed with collagenase. However, hormonal responses were the same for both types of cells. As compared to plastic, cells on a Matrigel substratum exhibited lower incorporation of [3H]thymidine and were unresponsive to hormones. Estradiol-17 beta increased [3H]thymidine incorporation slightly at 10(-10) mol/liter and higher. Epidermal growth factor, insulinlike growth factor-I, and insulinlike growth factor-II also stimulated [3H]thymidine incorporation. Effects of insulinlike growth factor-I were greater for cells treated with estradiol-17 beta. In the absence of estradiol, progesterone inhibited [3H]thymidine incorporation at 1, 10, and 100 ng/ml. When estradiol-17 beta was present, progesterone stimulated [3H]thymidine incorporation at 1 ng/ml and reduced incorporation at 100 ng/ml. In conclusion, [3H]thymidine incorporation by cultured oviductal endosalpingeal cells can be regulated by ovarian steroids and growth factors. These molecules may represent signals through which the ovary, embryo, and oviduct regulate oviductal growth.
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PMID:Steroidal and growth factor regulation of [3H]thymidine incorporation by cultured endosalpingeal cells of the bovine oviduct. 852 20

Previous studies have reported changes in proliferation, second-messenger generation and activation of various cellular processes when osteoblasts have been mechanically stimulated. Recent evidence suggests that mechanical loading of long bones induces immediate early-gene expression. Immediate early genes, such as Egr-1, are genes that control cell proliferation, are involved in signal transduction, and share properties of transcription factors. The purpose of this study was to examine how mechanical deformation of osteoblasts affects cellular proliferation and Egr-1 mRNA induction. Osteoblasts were isolated from collagenase digestion of newborn rat calvariae, cultured in Petri dishes with flexible bottoms and then constantly stretched, producing an increase of 3 or 7% in surface area. A mechanical stretch of 7% for 0.5 or 24 h resulted in a doubling of [3H]thymidine incorporation, while 50 nM of epidermal growth factor resulted in a 4-fold increase. A time-course experiment showed that a 7% stretch induced Egr-1 mRNA as early as 15 mm, reaching maximum levels by 60 min and returning to baseline by 120 min. Epidermal growth factor at 50 nM for 60 min resulted in a 3.8-fold Egr-1 mRNA induction. A mechanical stretch of 3% for 30 min also produced an Egr-1 mRNA induction. No induction of Egr-1 mRNA was seen in osteoblasts that were exposed to conditioned media from deformed cells. It is concluded that the immediate early gene, Egr-1, may be directly involved in the signal-transduction pathway of mechanical stimuli in osteoblasts.
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PMID:Immediate early-gene induction in rat osteoblastic cells after mechanical deformation. 913 99

An imbalance between the activity of matrix metalloproteinases (MMPs) (proteolytic enzymes that degrade protein components of the extracellular matrix) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), may be one of the mechanisms responsible for tumor cell invasion. We have investigated the regulation of MMP-1 and TIMP-1 gene expression in benign and malignant (follicular, anaplastic, and papillary) human thyroid cells. As expected of cells with invasive potential, detectable MMP-1 messenger RNA (mRNA) levels were observed in malignant cells under basal conditions, in contrast to undetectable levels in benign cells. Exposure of these cells, for 1 h, to the active phorbol ester, phorbol 12-myristate 13-acetate (TPA, 100 nmol/L), acting via protein kinase C (PKC), elicited an increase in MMP-1 mRNA, with a peak stimulation after a 3- to 4-h culture period. Epidermal growth factor (EGF, 25 ng/mL), however, acting via protein tyrosine kinase (PTK), stimulated such gene expression in malignant cells but failed to do so in benign cells. TIMP-1 mRNA was not significantly altered by the TPA-PKC, EGF-PTK, or TSH-protein kinase A (PKA) pathways in malignant cells. In benign cells, however, TPA induced a small, though significant, increase in TIMP-1. The MMP-1 stimulation by EGF and lack of TPA-induced rise in TIMP-1 in malignant cells, in sharp contrast to the effects obtained in benign thyrocytes, seems to indicate that the MMP: TIMP balance favors a more extensive extracellular matrix protein breakdown by malignant thyrocytes, as expected of cells exhibiting invasive capacity. TSH (10-500 microU/mL) failed to significantly influence basal MMP-1 or TIMP-1 mRNA levels, but it caused a dose-dependent inhibition in TPA- and EGF-induced MMP-1 mRNA in malignant cells, and TPA-stimulated MMP-1 and TIMP-1 in benign cells. The repressive action of TSH on MMP-1 mRNA was mimicked by forskolin and 8-bromo-cAMP and was abrogated by the PKA inhibitor, H-89, suggesting that the TSH inhibitory action is PKA-mediated. In conclusion, the present study provides novel data on MMP-1 and TIMP-1 gene expression and their modulation by the major signal transduction pathways operating in human thyroid cells. Similar and divergent patterns have emerged in the regulation of such gene expression in benign and malignant human thyrocytes, in many instances in accord with the concept of MMP playing the role of stimulating, and TIMP inhibiting, cell invasion. Although MMP-1 may be just one of the many factors responsible for tumor cell invasion, the present findings demonstrating the possibility, at least in vitro, of repressing MMP gene expression may have important clinical ramifications.
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PMID:Similar and divergent patterns in the regulation of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of MMP-1 gene expression in benign and malignant human thyroid cells. 1048 6


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