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)

Insulin is a major regulatory hormone for optimal tissue growth and function in utero. Its continued availability to the growing fetus depends on increasing islet cell mass. The purpose of the study was to examine the interactions between nutrient availability and insulin-like growth factor (IGF) release and action during DNA synthesis by isolated fetal rat islets of Langerhans. Specifically, we wished to determine (a) whether the availability of glucose or total amino acids altered the release of endogenous IGF-I or -II, (b) if both IGF-I and -II were effective mitogens for pancreatic beta-cells, (c) whether islets released IGF-binding proteins (IGFBPs) and their possible regulation by nutrient availability and (d) how IGFBPs might regulate the ability of IGFs to alter islet DNA synthesis. Islets of Langerhans were isolated from fetal rat pancreata on day 22 of gestation by collagenase digestion. Islets enriched in beta-cells following a 5-day preincubation regime were maintained in various concentrations of glucose (1.4-16.7 mmol/l) or amino acids (x1- x3 total concentrations), with or without exogenous IGF-I, -II, IGFBP-1 or IGFBP-2. The release of insulin and endogenous IGF-I and -II were each determined by radioimmunoassay, and IGFBP release characterized by Western ligand blot analysis. DNA synthesis was measured by the incorporation of [3H]thymidine. Isolated islets demonstrated an increased release of insulin in response to increasing amounts of both glucose and amino acids, demonstrating functional viability. Both classes of nutrients also increased the DNA synthetic rate of islets. Islets released almost twice as much IGF-II (0.22 +/- 0.08 nmol/l, mean +/- S.E.M., n = 4) as IGF-I (0.14 +/- 0.03 nmol/l) in cultures containing 8.7 mmol glucose/l and x1 amino acids. Lesser or greater concentrations of glucose did not alter the release of either IGF, but the release of IGF-II was significantly increased (0.53 +/- 0.08 nmol/l, P < 0.01) in the presence of x2 amino acids. Exogenous IGF-I was fivefold more active in stimulating DNA synthesis by islets (half maximal concentration (ED50) 1.6 +/- 0.4 nmol/l, n = 3) than was IGF-II (ED50 8.1 +/- 0.6 nmol/l), regardless of glucose concentration. Isolated islets released four species of IGFBP with molecular sizes of approximately 19, 25, 35 and 46 kDa respectively. The 35 kDa form was identified by Western immunoblot as IGFBP-2. Increasing the glucose concentration between 1.4 mmol/l and 16.7 mmol/l caused a dose-related increase in the release of the 19, 25 and 35 kDa IGFBP species.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Interactions of nutrients, insulin-like growth factors (IGFs) and IGF-binding proteins in the regulation of DNA synthesis by isolated fetal rat islets of Langerhans. 750 87

The ability of TSH to stimulate synthesis and release of thyroid hormones in ovine thyroid follicles in vitro depends partially on a synergy with insulin-like growth factors (IGFs). The cellular availability of IGFs may be influenced by the release of several IGF binding proteins (IGFBPs). The purposes of these studies was to 1) further characterize the species of IGFBPs synthesized by thyroid follicles, 2) examine the ability of TSH and cortisol to alter IGFBP gene expression and protein release, and 3) investigate the actions of exogenous IGFBPs on thyroid cell function. Adult sheep thyroid follicles were isolated after collagenase digestion, grown to confluence in Coon's modified Ham's F12M medium (OH) with the addition of transferrin, glycylhistidyl-lysine, somatostatin (3H), cortisol and insulin, and maintained in serum-free test media with or without further supplements for up to 48 h. Conditioned media were analyzed for IGFBP presence by Western ligand blotting, and by immunoblotting using specific antisera against bovine IGFBP-2 and human IGFBP-5. IGFBP mRNAs from follicles were identified by Northern blot hybridization using [32P]labeled complementary DNAs encoding ovine IGFBP-1 or -2, and rat IGFBP-4, -5, or -6. Uptake and organification of Na[125I] were measured by incorporation into trichloroacetic acid-precipitable material. Isolated thyroid follicles synthesized four species of IGFBPs in either 0H or 3H medium as detected by ligand blotting, of sizes 40-46, 34, 28, and 18 kilodaltons (kDa), respectively. The 32 kDa IGFBP was identified immunologically as IGFBP-2, whereas the 28 kDa and 18 kDa species were identified as IGFBP-5. Northern blot hybridization of total RNA from cells in 3H medium demonstrated an IGFBP-2 messenger RNA (mRNA) [1.4 kilobase (kb)], an IGFBP-4 mRNA (2.6 kb), and two IGFBP-5 mRNAs (6 kb and 1.8 kb). No IGFBP-1 or -6 mRNAs were detected. Incubation of cultured follicles with TSH (30-500 microU/ml) caused a dose-dependent decrease in the abundance of all IGFBP mRNAs and released proteins, which were reduced further by TSH together with cortisol (10 nM). When the inhibitory effect of TSH and cortisol was removed, IGFBP-2 mRNA increased within 3 h and was 7-fold greater within 12 h. IGFBP-2 did not appear in the conditioned medium until 12 h after TSH removal, along with the other IGFBP species.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hormonal regulation and biological actions of insulin-like growth factor binding proteins in isolated ovine thyroid follicles. 750 36

Nearly homogeneous preparations of stromal cells derived from human proliferative endometrium can be obtained by treating endometrial fragments with collagenase in order to disperse stromal elements, filtering the mixture a 25 microns opening sieve to separate them from gland, and incubating the dispersed cells to culture dishes. Exposure of stromal cell cultures to db-cAMP, 8-Br-cAMP or forskolin in RPMI 1640 medium containing 2% ct-FCS and 0.1 U/ml insulin induces the expression of prolactin (PRL), evident from 1) its secretion to the culture medium, measured by radioimmunoassay and by Western blot analysis, 2) the incorporation of 35S-methionine in a protein precipitated with a PRL antibody and co-migrating with authentic PRL during electrophoresis, and 3) the synthesis of PRL mRNA determined by Northern blot analysis. The cAMP effect on PRL production is enhanced by progestins, which by themselves are weak PRL inducers under similar experimental conditions. As expected from previous findings in our laboratory, showing that addition of PRL to the culture medium induces decidualization of endometrial stromal cells, cAMP derivatives not only induce PRL but also provoke differentiation of the fibroblast-like stromal cells to the decidual phenotype, as evident from morphologic changes and by the expression of products characteristic of decidual cells, e.g. IGFBP-1, desmin, hsp 27 and laminin. These findings suggest a PRL-mediated, progesterone-enhanced decidualization mechanism initiated by physiologic agents increasing cAMP levels in stromal cells.
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PMID:Mechanisms involved in the decidualization of human endometrial stromal cells. 798 67

We examined and compared the actions of IGF-I and -II on the release of insulin from isolated, intact rat islets of Langerhans within a perifusion system. Islets were isolated from adult male rats by collagenase digestion and Ficoll gradient separation, and were maintained in tissue culture for 48 h before perifusion. Following an equlibration period, islets were perifused with medium containing 2.7 mM glucose from 0 to 30 min. and 2.7, 11.1 or 16.7 mM glucose from 30 to 90 min. All chambers then received medium with 2.7 mM glucose from 90 to 120 min. Various doses (6.7-53 nM) of IGF-1, des(1-3) IGF-I or IGF-II were given either as a pulse between 30 and 35 min, or continuously from 30 to 90 min. Insulin was measured in effluent medium by RIA. When 11.1 mM glucose was administered after 30 min an immediate increase in insulin release occurred, from a baseline of 1-3 pmol/fraction to approximately 7 pmol/ fraction. The elevated rate of release was maintained until 90 min, and fell when the glucose concentration was lowered. Glucose at 16.7 mM was a less effective insulin secretogogue than was 11.1 mM. When islets received a pulse infusion of IGF-I (13.3 nM) at 30 min in the presence of 11.1 mM glucose, a statistically significant increase (p < 0.005) in insulin release occurred, of approximately 10 pmol/fraction in excess of that seen with glucose alone. The IGF-1-stimulated insulin release was still higher than controls at 115 min. When the concentration of IGF-I was altered between 6.7 nM and 53 nM, maximum insulin release was achieved with 13.3 nM IGF I, both lower and higher concentrations being less effective. A significant inhibition of insulin release occurred with 53 nM IGF-I compared with glucose alone. IGF-II (13.3 nM) did not significantly increase insulin release, while 53 nM IGF-II significantly inhibited release of insulin relative to controls. Des(1-3) IGF-I (13.3 nM), which has a reduced binding affinity for IGF-binding proteins (IGFBPs), administered with 11.1 mM glucose caused an immediate increase in insulin release, which fell to control values within 30 min. Western ligand blot analysis identified four IGFBP species in perifused islets, of 46 kDa, 35 kDa, 28 kDa, and 19 kDa respectively, of which the 28 kDa species was identified immunologically as IGFBP-1. When IGF-I was administered continuously from 30 to 90 min it inhibited glucose-stimulated insulin release at all concentrations used. The results suggest that under perfusion conditions, IGF-I can act both as a potent insulin secretogogue, augmenting the actions of glucose, and as an inhibitor of insulin release, depending on concentration and kinetics of administration.
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PMID:IGF-I has a dual effect on insulin release from isolated, perifused adult rat islets of Langerhans. 913 65

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

There is a growing interest in the role that cancer biomarkers, metastasis-related molecules, and chemokines may play in the development and progression of various cancers. However, few studies have addressed the reliability of such biomarkers in healthy individuals over time. The objective of this study was to investigate the temporal reliability of multiple proteins in serum samples from healthy women who donated blood over successive years. Thirty five, postmenopausal women with two, repeated annual visits, and thirty, premenopausal women with three, repeated annual visits were randomly selected among eligible subjects from an existing, prospective cohort. Multiplexing Luminex xMAPTM technology was used to measure the levels of 55 serum proteins representing cancer antigens, chemokines, angiogenic and anti-angiogenic factors, proteases, adipokines, apoptotic molecules, and other markers in these women. The biomarkers with high detection rates (> 60%) and acceptable reliability (intraclass correlation coefficient, ICCs > or = 0.55) using xMAPTM method were: cancer antigens: AFP, CA 15-3, CEA, CA-125, SCC, SAA; growth factors/related molecules: ErbB2, IGFBP-1; proteases and adhesion molecules: MMP-1, 8, 9, sE-selectin, human kallikreins (KLK) 8,10, ICAM-1, VCAM-1, chemokines: fractalkine, MCP-1,2, RANTES, MIP-1alpha, MIP-1beta, Eotaxin, GRO-alpha, IP-10; inhibitors of angiogenesis: angiostatin and endostatin; adipokines leptin and resistin; apoptotic factor: Fas, and other proteins mesothelin, myeloperoxidase (MPO), and PAI-1. The rest of the biomarkers under investigation either had ICCs less than 0.55 or had low levels of detection (< 60%). These included cancer antigens: CA 19-9, CA 72-4, MICA, S100, TTR, ULBP1, ULBP2, ULBP3; proteases: MMP 2, 3, 7, 12, 13; chemokines: MCP-3, MIF, MIG; adipokines: leptin and resistin; apoptotic factors: FasL, DR5, Cyfra 21-1; and inhibitors of angiogenesis and other markers: thrombospondin and heat shock protein (HSP) 27. In conclusion, 34 out of the 55 biomarkers investigated were present in detectable levels in > 60% of the samples, and with an ICC > or = 0.55, indicating that a single serum measurement can be used in prospective epidemiological studies using the xMAPTM method.
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PMID:Reliability of tumor markers, chemokines, and metastasis-related molecules in serum. 1931 17

Lower level of insulin-like growth factor-binding protein (IGFBP-1) has been observed in insulin resistance, while higher level of matrix metalloproteinase-8 (MMP-8) has been linked to obesity. The aim here was to study in overweight and obese women, typically manifesting with insulin resistance, whether IGFBP-1 and MMP-8 are related to and reflect systemic low-grade inflammation, metabolism and diet. Fasting serum from overweight and obese pregnant women (n = 100) in early pregnancy were analysed for IGFBP-1, phosphorylated IGFBP-1 (phIGFBP-1) and MMP-8. High-sensitivity CRP and GlycA were used as markers for low grade inflammation. GlycA and lipids were quantified using NMR. IGFBP-1 associated negatively with GlycA, evidenced by higher concentrations in the lowest quartile (median 1.53 (IQR 1.45-1.72)) compared to the highest (1.46 (1.39-1.55)) (P = 0.03). Several lipid metabolites, particularly HDL-cholesterol, correlated inversely with phIGFBP-1 (FDR<0.1). Nutritional status and diet contributed to the levels of IGFBP-1, demonstrated as an inverse correlation with maternal weight (Spearman r = -0.205, P = 0.04) and dietary intake of vitamin A (r = -0.253, P = 0.014) and a direct correlation with dietary intake of polyunsaturated fatty acids (Spearman r = 0.222, P = 0.03). MMP-8 correlated inversely with pyridoxine (r = -0.321, P = 0.002) and potassium (r = -0.220, P = 0.033). Maternal serum IGFBP-1 may contribute to maternal lipid metabolism in overweight and obese women during early pregnancy. These findings may be of importance in identification of metabolic disturbances preceding the adverse metabolic outcomes in pregnancy.
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PMID:Early pregnancy serum IGFBP-1 relates to lipid profile in overweight and obese women. 3313 76