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)

Isolated sheep thyroid follicles release specific insulin-like growth factor-binding proteins (IGFBPs). Since IGFBPs can modulate IGF bioactivity, at least in vitro, their presence in thyroid tissue may influence synergistic interactions between TSH and endogenous IGF-I or -II which are known to control both thyroid growth and function. We have examined the hormonal control of IGFBP release in relation to iodine organification. Sheep thyroid follicles were isolated by incubation with collagenase and differential centrifugation, grown in Coon's modified Ham's F12M medium with the addition of transferrin, glycylhistidyl-lysine, somatostatin (3H), TSH, cortisol and insulin (6H), and maintained in OH (hormone-free) or 3H medium with or without further supplements for 48 h. Conditioned culture medium was separated by 8% sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis, transferred to nitrocellulose and incubated with 125I-labelled IGF-II followed by autoradiography (ligand blot). Additionally, the radioactive bands were cut from the filters and quantified by gamma-spectrometry. Iodine organification was assessed by incubation of follicles with 10(6) c.p.m. Na125I for 3 h before washing, solubilization in 0.1 mol NaOH/l and the precipitation of organified radioisotope with 10% (v/v) trichloroacetic acid. Cells conditioned in OH or 3H medium released specific IGFBPs of 46, 34, 28 and 19 kDa on ligand blot analysis. The proteins of 34 and 19 kDa were immunopositive on Western blot analysis using anti-bovine IGFBP-2 antiserum. The 46-kDa IGFBP was retained by Concanavalin A-Sepharose chromatography and demonstrated to be glycoprotein. This is probably ovine IGFBP-3. The addition of TSH, or TSH plus cortisol to OH or 3H medium significantly decreased the 125I-labelled IGF-II associated with the 34- and 28-kDa IGFBP species. All IGFBP species were substantially reduced in 6H medium, which was predominantly due to the effects of TSH and cortisol. When total 125I-labelled IGF-II associated with IGFBPs was considered, a significant (P less than 0.01) inverse correlation existed between IGFBP activity and iodine organification in the same cultures; the latter being greatest in OH or 3H medium supplemented with TSH and cortisol. None of these hormone additions altered the endogenous release of IGF-II by the cells. These results suggest that endogenous IGFs, under hormonal control, may modulate the action of endogenous IGF in the regulation of thyroid function.
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PMID:Hormonal regulation of insulin-like growth factor (IGF)-binding proteins secreted by isolated sheep thyroid epithelial cells: relationship with iodine organification. 171 78

Insulin-like growth factor binding protein-3 (IG-FBP-3) is degraded by a Zn(2+)-dependent protease(s) produced by human dermal fibroblasts in vitro (Fowlkes, J. (1994) Endocrine J. 2, 63-68). Initial studies using IG-FBP-3-substrate zymography identified several IGFBP-3-degrading proteases with M(r) 52,000-72,000, which were inhibitable by EDTA and were shifted to lower M(r) species after treatment of conditioned medium with an organomercurial, suggesting that they might represent one or more of the matrix metalloproteinases (MMPs). Immunoblotting of conditioned medium demonstrated the presence of proMMP-1 (52 and 55 kDa), proMMP-3 (58 and 60 kDa), and proMMP-2 (72 kDa) whose molecular masses corresponded identically to those of the IGFBP-3-degrading proteases. Degradation of recombinant human (rh) IGFBP-3 by conditioned media was blocked (> 80% inhibition) by tissue inhibitor of metallo-proteinases-1, a specific inhibitor of all MMPs, while removal of MMPs -1, -2, and -3 from conditioned medium by sequential immunoaffinity and gelatin-Sepharose chromatography resulted in the complete loss of IGFBP-3-degrading proteinase activity. Furthermore, human MMP-1, MMP-3, and to a lesser extent MMP-2 degraded rhIGFBP-3 in vitro. Sequence analysis of rhIGFBP-3 cleavage sites produced by MMP-1, -2, or -3 demonstrated that each cleaved within the mid-region of the binding protein, a domain with little or no homology with the other five cloned IGFBPs. These studies suggest that MMPs, beyond their previously described functions as extracellular degrading enzymes, may also exert effects on cellular growth and proliferation via degradation of IGFBP-3, thus enhancing IGF bioavailability.
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PMID:Matrix metalloproteinases degrade insulin-like growth factor-binding protein-3 in dermal fibroblast cultures. 752 91

In the pig, the corpus luteum (CL) can develop and function autonomous of pituitary gonadotropins for approximately 12 days. We hypothesized that the insulin-like growth factor (IGF) system may play an autocrine/paracrine luteotrophic role(s) during this period. In this study, we monitored the expression (i.e., steady-state levels of mRNAs) of IGF-I and IGF binding proteins (IGFBP)-2, -3, -4, -5, and -6 mRNAs in whole CL and in small and large luteal cells on Days 4-16 of the estrous cycle. CL were dissociated with collagenase, and large and small luteal cells were isolated by centrifugal elutriation. Whole CL and luteal cells were extracted to isolate total or poly(A)+ RNA, which was subjected to Northern and/or dot-blot analyses using [32P]-labeled cDNA probes for IGF-I and IGFBP-2, -3, -4, -5, and -6. Northern blots showed readily detectable transcripts for IGF-I (6.7 and 0.9 kb), IGFBP-2 (1.8 kb), IGFBP-3 (2.8 kb), IGFBP-4 (2.6 kb), and IGFBP-5 (6.0 kb), but not for IGFBP-6. IGFBP-3 and -5 transcripts were observed mainly in small luteal cells, while IGFBP-2 and -4 were seen in both cell types. Dot-blot analyses for IGF-I and IGFBP-3 mRNAs were performed on total RNA from small and large luteal cells; blots were counter-probed with 3-phosphoglyceraldehyde dehydrogenase (p-GAD) cDNA to assess RNA quantity and quality. IGF-I mRNA (ratio IGF-I:p-GAD mRNA) expression was approximately 2-fold greater in small than in large luteal cells on Days 4-10. However, steady-state levels of IGF-I mRNA in small, but not large, luteal cells decreased significantly on Days 12-16 (vs. Days 4-10). IGFBP-3 mRNA expression was significantly greater (approximately 3-fold) in small than in large luteal cells but did not vary significantly between Days 4-10 and 12-16 for either cell type. We conclude that porcine CL express mRNAs for IGF-I and IGFBP-2, -3, -4, and -5, and that while small luteal cells are the major sources of IGF-I and IGFBP-3 and -5, IGFBP-2 and -4 appear to be expressed to approximately the same extent in small and large luteal cells. These results further suggest that the IGF-I/IGF system may have autocrine/paracrine regulatory actions in CL development/function in the pig.
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PMID:Expression of the messenger ribonucleic acids for insulin-like growth factor-I and insulin-like growth factor binding proteins in porcine corpora lutea. 878 84

The IGFBP proteases were first described in pregnancy serum as a proteolytic activity against IGFBP-3. Since then, IGFBP proteases have been described in many other clinical situations, in various body fluids, and have been shown to cleave IGFBP-2 to -6 with varying specificity. The molecular nature of some of these proteases is being unraveled and three classes of IGFBP proteases have been recognized. These include kallikreins, cathepsins and matrix metalloproteinases (MMPs). We utilized two cellular systems to demonstrate the significance of IGFBP proteases in cellular growth regulation. In primary cultures of prostatic cells, we have shown that prostate-specific antigen (PSA) has the ability to enhance IGF mitogenic action by reducing the effects of IGFBPs. Similar kallikreins such as gamma nerve growth factor (NGF) share this activity. Within the prostatic milieu, we have also demonstrated epithelial production of the acid-activated IGFBP protease, cathepsin D, and its secretion into seminal plasma, as well as the serum of patients with prostate malignancy. We have also identified MMPs in prostatic cells and fluids. Using cultured airway smooth muscle (ASM) cells, we have demonstrated the synergism between IGFs and inflammatory agents in mediating ASM cell proliferation. Examination of this phenomenon revealed that these agents (e.g. leukotriene D4 and interleukin1-beta) induce the secretion of an IGFBP protease which cleaves the IGFBPs secreted by ASM cells, allowing IGFs to stimulate proliferation. Using several methods, including immunoblotting and immunodepletion techniques, we have identified this protease as MMP-1. These two pathophysiological systems demonstrate the importance of IGFBP proteases as autocrine paracrine growth regulators. Furthermore, IGFBP proteases may be critical elements in malignant and benign proliferative diseases, including prostate cancer and the ASM hyperplasia of long-standing asthma.
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PMID:Insulin-like growth factor binding protein (IGFBP) proteases: functional regulators of cell growth. 881 70

Insulin-like growth factor binding proteins (IGFBP) proteases have been proposed to be involved in changes of serum IGFBP pattern during pregnancy. IGFBP-4 and -5 are degraded specifically by proteases in pregnancy serum in vitro, whereas IGFBP-3 proteolytic activity was also detected in nonpregnancy serum. To identify and characterize IGFBP proteases, human pregnancy serum was fractionated by size exclusion chromatography revealing IGFBP-4 protease activities in fractions coeluting with proteins of approximately 600-kDa and 50- to 100-kDa molecular mass. In both fractions, a predominant 50-kDa gelatinase was found, suggesting that parts of the gelatinase activity might aggregate or are complexed with other proteins forming a higher molecular complex. Hydroxyapatite chromatography and chromatofocusing of the 50- to 100-kDa serum fraction showed that the IGFBP-4 protease and the 50-kDa gelatinase activity were copurified. When the 50-kDa gelatinase-containing band was excised from the polyacrylamide gel, it exhibited IGFBP-4 proteolytic activity, resulting in the formation of 17- and 10-kDa fragments. [125I] IGFBP substrate zymography combined with fragment blotting showed that the 1,10-phenanthroline-sensitive 50-kDa protease activity purified by chromatofocusing also cleaved IGFBP-3 and -5. Other proteases detected in pregnancy serum fractions with Mr estimates of 79-, 30-, and 22-kDa degraded IGFBP-3 and -5 but not IGFBP-4. [125I] IGFBP-5 substrate zymography revealed that the 30-kDa IGFBP protease was inhibited by serine protease inhibitors. Whereas 1,10-phenanthroline inhibited the IGFBP proteolytic activity in the solution assay, serine protease inhibitors failed to affect proteolysis, indicating the predominant contribution of the metalloproteinase to IGFBP proteolysis. Tissue inhibitors of matrix metalloproteinases-1 and -2 revealed weak or no inhibition of IGFBP-4 and -5 proteolytic activity, whereas a hydroxamic acid-based inhibitor, potentially inhibiting disintegrin metalloproteases, completely prevented the proteolysis of IGFBPs. Whereas no specific immunoreactivity of the 50-kDa protein with antimatrix metalloproteinase-1, -2, -3, -9, or -13 antibodies was observed, antidisintegrin domain-specific antibodies bound to the 50-kDa gelatinase. These studies provide the first direct biochemical evidence that human pregnancy serum contains a 50-kDa IGFBP protease with properties of a soluble disintegrin metalloproteinase that appears to be potentially involved in regulating IGF bioavailability for placental and fetal growth.
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PMID:Proteolysis of insulin-like growth factor binding proteins by a novel 50-kilodalton metalloproteinase in human pregnancy serum. 952 34

We have previously demonstrated that the asthma-associated proinflammatory eicosanoid leukotriene D4 (LTD4) is co-mitogenic with insulin-like growth factors (IGFs) in airway smooth-muscle (ASM) cells in vitro. This synergistic effect of LTD4 and IGF on ASM cell growth involves proteolysis of ASM-produced IGF binding proteins (IGFBPs), which are cell growth-inhibitory proteins. We also identified this IGFBP protease to be the matrix metalloproteinase-1 (MMP-1), and showed that this enzyme had a significant role in modulating IGF action in ASM cells. In the present study, we tested the hypothesis that ASM hyperplasia in vivo involves induction of MMP-1 leading to IGFBP proteolysis. We detected the presence of MMP-1 and measured its levels in human airway tissue sections prepared from nonasthmatic and asthmatic subjects. Six nonasthmatic and six asthmatic airway tissue samples were analyzed for immunoreactive MMP-1 through an immunohistochemical detection method. Both the bronchial and tracheal smooth-muscle cells from different regions of the same sample were examined and documented. The immunostaining for MMP-1 was significantly elevated in both the bronchial and tracheal smooth-muscle cells of the airway sections from asthmatic samples relative to that of the nonasthmatic samples. The differences in levels of MMP-1, IGFBP-2, IGFBP-3, and IGFBP proteolytic activity were quantified using densitometric analyses of the ASM tissue extracts that were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The MMP-1 levels in the asthmatic airway tissue extracts were 12-fold higher than those found in control samples. In addition, IGFBP-2 and IGFBP-3, which we have previously demonstrated to be proteolytic substrates of MMP-1, were found to be cleaved in asthmatic airway tissue extracts. Furthermore, the asthmatic airway extracts contained IGFBP proteolytic activity that was shown by immunodepletion studies to be due to MMP-1. These observations demonstrate that MMP-1 may play a significant role in inducing ASM hyperplasia and airway obstruction in asthma by modulating the IGF axis.
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PMID:Elevated levels of the IGF-binding protein protease MMP-1 in asthmatic airway smooth muscle. 992 10

During the course of human pregnancy, there is a marked increase in insulin-like growth factor (IGF) binding protein (IGFBP)-3 protease activity in maternal serum that is first evident at 6 weeks of gestation, persists through term, and returns to nonpregnancy levels by day 5 postpartum. This protease activity cleaves IGFBP-3 into smaller fragments that have markedly reduced affinity for the IGFs. To date, the precise identity and cellular origin of the pregnancy-associated serum IGFBP-3 protease have not been established. To investigate whether placental and/or decidual tissues, which uniquely develop during pregnancy, may be sources of the pregnancy-associated serum IGFBP protease, we examined the secretion of IGFBP-3 protease in vitro by isolated human cytotrophoblasts or fibroblasts from second trimester placentae and by in vitro decidualized human endometrial stromal cells. Cytotrophoblasts were either cultured alone, which favors aggregation and fusion, or cocultured with decidualized endometrial stromal cells, which favors differentiation to an invasive phenotype. IGFBP-3 protease activity was detected in trophoblast, but not in placental fibroblast or decidualized endometrial cultures, and was also present in trophoblast-endometrial cocultures. Western ligand blot and Western immunoblot analyses showed that most of the endogenous IGFBP-3 in trophoblast cultures was in the form of low molecular weight fragments with reduced IGF binding affinity. The substrate specificity of the trophoblast-derived protease was identical to that in pregnancy serum, showing activity against IGFBP-2, -3, and -4, but being inactive against IGFBP-1. IGFBP-3 proteolysis by both pregnancy serum and trophoblast conditioned medium showed a major peak of activity at neutral pH. The trophoblast-derived activity caused time-and temperature-dependent proteolysis of IGFBP-3 into fragments of identical size as those produced by pregnancy serum, and also shared its sensitivity to protease inhibitors: highly sensitive to EDTA and o-phenanthroline, partially sensitive to the serine protease inhibitors AEBSF and aprotinin, and insensitive to alpha2-antiplasmin, and to aspartic and cysteine protease inhibitors. IGFBP-3 proteolysis by both pregnancy serum and trophoblast conditioned medium was also insensitive to tissue inhibitor of metalloproteinase-1, precluding the involvement of the matrix metalloproteinases. In contrast, both the pregnancy serum- and trophoblast-derived proteases were preferentially inhibited by a hydroxamic acid derivative with selective activity against the disintegrin-metalloproteinase tumor necrosis factor-alpha converting enzyme. This study shows that placental trophoblasts produce an IGFBP-3 protease with characteristics very similar to the activity found in pregnancy serum and indicates these cells at the maternal-fetal interface are a potential source of the pregnancy-associated serum IGFBP-3 protease. The findings further suggest that the main IGFBP-3 protease activity in both pregnancy serum and trophoblast conditioned medium may correspond to a disintegrin-metalloproteinase type enzyme.
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PMID:Human placental trophoblasts secrete a disintegrin metalloproteinase very similar to the insulin-like growth factor binding protein-3 protease in human pregnancy serum. 1065 Sep 48

Successful transplantation of autologous chondrocytes for repair of articular cartilage defects requires an undisturbed matrix-synthesis of the transplanted cells. This, in turn, is dependent on the composition of the synovial fluid (SF) of the respective joint. We addressed the question whether analysis of a patient's SF can predict the rate of matrix-synthesis of articular cartilage exposed to this SF in vitro. SF was obtained from 115 patients with disorders of the knee, including gonarthrosis (n = 44), meniscal tears (n = 10), rheumatoid arthritis (n = 53), and reactive arthritides (n = 8). In the SF, the following parameters were determined: Interleukin-1 beta, IL-6, IL-8, IL-1-RA, TNF alpha, Insulin-like growth-factor I (IGF-I), IGF-II, IGF-binding protein-2 (IGFBP-2), IGFBP-3 as well as total proteinase activity and total collagenase activity. To assess the effect of SF on the matrix synthesis of articular chondrocytes, bovine cartilage was incubated in the presence of SF, and the rate of proteoglycan synthesis subsequently determined. In some cases, a monoclonal antibody directed against IGF-I was added. SF from patients with OA or trauma, respectively, stimulated PG-synthesis of bovine cartilage more markedly than did SF from patients with rheumatic arthritides. On the average, 60 percent of the SF-induced increase of cartilage matrix synthesis could be titrated out by an anti-IGF-I-AB. The best predictor for the SF-effects on PG-synthesis of exposed cartilage was the proportion of free IGF-I (r = 0.573, p < 0.001, Spearman rank correlation) followed by the SF-concentrations of IGF-I (with a positive sign), IGFBP-3, IL-1 beta, and TNF alpha (all with a negative sign). According to our data, IGF-I is the most important anabolic factor in human SF with respect to cartilage PG-synthesis. The proportion of free IGF-I seems to be of special importance in this regard. Low SF-levels of free IGF-I could be identified as a possible risk-factor for a sub-optimal protoeglycan synthesis of chondrocytes exposed to this synovial milieu.
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PMID:[Value of synovial analysis for prognosis of matrix synthesis of transplanted chondrocytes]. 1074 38

This study investigates the systemic biochemical regulation of fracture healing in distraction osteogenesis compared with rigid osteotomy in a prospective in vivo study in humans. To further clarify the influence of mechanical strain on the regulation of bone formation, bone growth factors (insulin-like growth factor [IGF] I, IGF binding protein [IGFBP] 3, transforming growth factor [TGF] beta1, and basic FGF [bFGF]), bone matrix degrading enzymes (matrix-metalloproteinases [MMPs] 1, 2, and 3), human growth hormone (hGH), and bone formation markers (ALP, bone-specific ALP [BAP], and osteocalcin [OC]) have been analyzed in serum samples from 10 patients in each group pre- and postoperatively. In the distraction group, a significant postoperative increase in MMP-1, bFGF, ALP, and BAP could be observed during the lengthening and the consolidation period when compared with the baseline levels. Osteotomy fracture healing without the traction stimulus failed to induce a corresponding increase in these factors. In addition, comparison of both groups revealed a significantly higher increase in TGF-beta1, IGF-I, IGFBP-3, and hGH in the lengthening group during the distraction period, indicating key regulatory functions in mechanotransduction. The time courses of changes in MMP-1, bone growth factors (TGF-beta1 and bFGF), and hGH, respectively, correlated significantly during the lengthening phase, indicating common regulatory pathways for these factors in distraction osteogenesis. Significant correlation between the osteoblastic marker BAP, TGF-beta1, and bFGF suggests strain-activated osteoblastic cells as a major source of systemically increased bone growth factors during callus distraction. The systemic increase in bFGF and MMP-1 might reflect an increased local stimulation of angiogenesis during distraction osteogenesis.
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PMID:Systemic regulation of distraction osteogenesis: a cascade of biochemical factors. 1209 42

Insulin-like growth factor (IGF) -I is one of the candidates for cardiac hypertrophy induced by beta-adrenergic stimulation. However, the mechanisms by which the biologic actions of IGF-I are regulated under this condition remain unclear. IGF-I becomes bioavailable for its receptors upon its dissociation from IGF-binding protein (IGFBP) through IGFBP degradation. Because matrix metalloproteinases (MMPs) have been implicated in the degradation of IGFBPs, the authors investigated the role of MMPs in the regulation of the IGF-I action through the degradation of IGFBPs in cardiac hypertrophy induced by beta-adrenergic stimulation. They examined the expression of MMPs in cardiac tissues of rats infused with isoproterenol (3 mg/kg per day), the effect of a MMP inhibitor, SI-27 (5 mg/rat per day), on cardiac hypertrophy, and the expression of IGF-I and IGFBP-3. MMP-1 and -2 activities increased and IGFBP-3 was degraded in heart hypertrophied by isoproterenol. MMP inhibition caused a regression in the myocyte hypertrophy in association with the suppression of both IGF-I protein in myocytes and the degradation of IGFBP-3 protein. These results suggest that the induction of myocyte hypertrophy by isoproterenol is mediated, at least in part, by a modulation of the IGF-I axis.
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PMID:Inhibition of matrix metalloproteinases prevents cardiac hypertrophy induced by beta-adrenergic stimulation in rats. 1288 19


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