Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Samples from the ascending aortae from two calves affected by bovine Marfan syndrome were subjected to biochemical analyses of the connective tissue and were compared to age-matched controls. Elastin was extracted from the aortic samples with 5 M guanidine-HCl, bacterial collagenase digestion, and dithiothreitol reduction. Amino acid analysis revealed that desmosine and isodesmosine levels were the same in Marfan calves as in control animals. Gravimetric measurements of elastin, amino acid composition, soluble protein, and uronic acid values also showed no significant difference between Marfan and control tissue. In contrast to elastin, collagen in aortae of Marfan calves was significantly higher than the mean of several controls. These findings, along with other observations of this animal model, support the conclusion that the microscopic and biochemical lesions of aortic elastin in bovine Marfan syndrome likely result from defective microfibrillar metabolism. Absence of cystic medial necrosis in bovine Marfan aortae may explain normal elastin content in the animal model.
Exp Mol Pathol 1992 Oct
PMID:Normal elastin content of aorta in bovine Marfan syndrome. 142 58

The adult newt cardiac ventricular myocyte has been successfully placed in cell culture and has been shown to undergo in vitro DNA synthesis. Although several growth factors have been reported to increase DNA synthesis in cardiac myocytes in vitro, PDGF has not been reported to do so, but has been shown to be active in other systems. Ventricles were removed from the adult red-spotted newt and were enzymatically and mechanically dissociated in a solution containing trypsin and collagenase. Cells were preplated on to plastic to remove non-myocytes. Myocytes were then plated onto laminin. Groups of myocytes were fed control medium and medium containing porcine PDGF. Myocytes were given 1 microCi/ml of tritiated thymidine 6 or 24 h before fixation. Control myocytes showed a peak DNA synthesis at 12-14 days in culture. One ng/ml of PDGF increased DNA synthesis significantly to 22% above control. Myocytes responded to PDGF with significantly increased DNA synthesis in about 12 h. PDGF did not induce earlier DNA synthesis, but increased synthesis at all days of culture tested. These results indicate that PDGF acts upon cardiac myocytes, increasing their DNA synthesis.
J Mol Cell Cardiol 1992 Sep
PMID:Stimulation of DNA synthesis by PDGF in the newt cardiac myocyte. 143 20

We have established a monolayer culture system for human fallopian tube epithelial cells. The cells were isolated from tubes using collagenase digestion, and were cultured in Ham's F-10 supplemented with 15% fetal calf serum. The epithelial cells derived from culture were characterized using immunocytochemical staining and electron microscopy. These cells were stained with antikeratin and anti-epithelial membrane antigen, but showed no staining after treatment with antivimentin. Electron microscopy showed many microvilli on the cell surface and tight junctions or desmosomes at areas of cell-cell contact. Cell proliferation was enhanced by epidermal growth factor, but not by fibroblast growth factor, insulin, transferrin, estradiol-17 beta, or progesterone. The 2-cell ICR mouse pre-embryos were co-cultured for 4 days with tubal epithelial cells (A) (n = 98), in cell-conditioned medium (B) (n = 83), or in medium alone (C) (n = 72). During the first 24 h in culture, for groups A and B, the rates of cleavage to the 4-cell stage were 90.9% and 81.9%, respectively. Cleavage rates in these two groups were significantly higher (P = 0.0012, P less than 0.00001) than in group C (56.9%). After 72 h in culture, the rates of development to the blastocyst stage were significantly higher for groups A and B compared to group C (89.6% and 73.5% vs. 54.5%, P less than 0.00001, P = 0.0002). These results suggest that factor(s) from tubal epithelial cells may facilitate the development of mouse pre-embryos throughout the pre-implantation stages.
Mol Reprod Dev 1992 Jul
PMID:Primary culture of human fallopian tube epithelial cells and co-culture of early mouse pre-embryos. 149 73

An investigation of myocardial glycoproteins was undertaken to elucidate the molecules responsible for the periodic acid-Schiff (PAS) reactivity of the increased extracellular matrix of diabetic cardiomyopathy. Perfusion with radiolabeled mannose indicated an enhanced formation of matrix components in the diabetic compared to the normal rat heart. Electrophoretic separation of radiolabeled extracts demonstrated the presence of glycoproteins with Mr values of 205, 142 and 90 kDa which could be separated by Bio-Gel A-5 m filtration. Fractionation of non-perfused hearts resulted in the isolation of only the 205 and 142 kDa components, which were shown by amino acid analyses and collagenase digestion to belong to the collagen family of proteins and by immunoblotting to represent type VI collagen. The carbohydrate content of these rat myocardial type VI collagen subunits, determined from monosaccharide analyses, was 11 and 12%, respectively, and N-glycanase digestion of the 142 kDa chain resulted in a decrease in size of approximately 14 kDa, indicating the presence of asparagine-linked units. Examination of normal and diabetic rat heart sections indicated that the latter contained abundant PAS-positive strands and nodules which corresponded to the distribution of anti type VI collagen reactivity. Moreover, immunoblots showed higher levels of Type VI collagen in diabetic than in normal heart extracts. Type VI collagen therefore appears to represent a major glycoprotein of myocardial extracellular matrix and to be implicated in diabetic cardiomyopathy.
J Mol Cell Cardiol 1992 Apr
PMID:Myocardial glycoproteins in diabetes: type VI collagen is a major PAS-reactive extracellular matrix protein. 161 69

Stromelysin gene expression is transcriptionally activated by a number of growth factors (e.g., EGF and PDGF), tumor promoters (e.g., TPA), and oncogenes (e.g., ras, src) through an AP-1-dependent mechanism. TGF-beta repression of stromelysin induction is mediated at the level of transcription by an element located at position -709 in the rat stromelysin promoter referred to as the TGF-beta inhibitory element (TIE). A TIE-binding protein complex is induced by treatment of rat fibroblasts with TGF-beta. This protein complex contains the protooncogene c-fos, and induction of c-fos by TGF-beta is required for the repressive effects of TGF-beta on stromelysin gene expression. Interestingly, c-fos induction is also required for stimulation of stromelysin expression by EGF in rat fibroblasts. Preliminary studies suggest that differential regulation of members of the jun family of early-response genes may explain this apparent paradox and determine whether stromelysin is induced or repressed by growth factors. TGF-beta stimulation therefore initiates a cascade of events that results in a specific pattern of gene expression: the direct stimulation of early-response genes can lead to subsequent induction or repression of other genes. Growth factor regulation of matrix metalloproteinases appears to play a role in embryonic development in the morphogenesis of the murine lung. Treatment of embryonic lungs in organ culture with the growth factors EGF or TGF-alpha results in stimulation of growth and inhibition of branching morphogenesis. A similar inhibition of branching was observed when these lung rudiments were treated with the matrix metalloproteinase collagenase. Most interestingly, the effects of EGF and TGF-alpha can be completely reversed by the tissue inhibitor of metalloproteinases, TIMP. TGF-beta has the opposite effect on growth of murine lung rudiments--growth is inhibited in a dose-dependent manner. This example illustrates a potential role for growth factor regulation of matrix-degrading metalloproteinases in complex developmental processes.
Mol Reprod Dev 1992 Jun
PMID:Negative regulation of gene expression by TGF-beta. 163 49

We have studied the effects of acute administration of triiodothyronine (T3) on cytosolic free calcium levels [Ca2+]i in single rat myocytes microinjected with aequorin. Ventricular myocytes were isolated by perfusing rat hearts with collagenase, and healthy, rod-shaped cells were injected to less than 1% of their volume with aequorin. The photons emitted from single cells were measured and a conversion to [Ca2+]i made on the basis of an in vitro calibration after the remaining aequorin had been discharged by cell lysis. Only cells that depolarized reversibly (showing elevated [Ca2+]i levels) when superfused with 80 mM KCl, and which gave a substantial signal on lysis with distilled water were used. The [Ca2+]i rose from a resting value of 150 +/- 56 nM (mean +/- SD, n = 14) by 127 +/- 47 nM on depolarization with 80 mM KCl. Application of T3 (1-100 nM) led to an increase (P less than 0.05) in [Ca2+]i (mean amplitude of 152 +/- 35 nM) before returning to baseline. The median duration of these events was 10 min (range = 1.4-34.4 min). The time to response was shorter when 100 nM T3 was applied (median and range; 6.8, 0-14 min) than when 1 nM T3 was used (16, 7.0-56.1 min) (P less than 0.05). To conclude, physiological concentrations of thyroid hormones caused rapid but transient stimulation of [Ca2+]i in single rat myocytes.
J Mol Endocrinol 1991 Aug
PMID:Tri-iodothyronine increases intra-cellular calcium levels in single rat myocytes. 165 54

Samples of rat alveolar bone were first treated by collagenase digestion and then used as explants for cell culture. The cells obtained were subcultured and characterized by morphological and functional criteria. Their alkaline phosphatase activity was increased after incubation in 1,25-(OH)2 vitD3 10(-8) M whereas with gingival cells it did not change. The bone derived-cells organized nodular structures, synthesized type I collagen, Gla-protein, few type III collagen, and fibronectin. In the defined culture conditions no mineralization was observed. However, the method used allows to obtain cells from rat alveolar bone displaying some features of the osteoblastic phenotype.
Cell Mol Biol 1991
PMID:Isolation and characterization of rat alveolar bone cells. 165 92

The inward chloride current induced by angiotensin II (AII) in Xenopus oocytes shows strong and homologous desensitization, and was suggested to be mediated by phosphatidylinositol (PI) hydrolysis (Sakuta et al., 1991, Eur. J. Pharmacol. Mol. Pharmacol. 208, 31). As a model of agonist-induced desensitization of receptors coupled with PI hydrolysis, the mechanism of the desensitization of endogenous AII receptors in oocytes was investigated. Incubation of collagenase-treated oocytes with staurosporine significantly augmented the peak amplitude of AII responses, prolonged their duration, and increased the ratio of oocytes responsive to AII. Moreover, staurosporine-pretreatment made oocytes be consistently responsive to every application of AII. These effects of staurosporine were inhibited by incubation of staurosporine-treated oocytes with 12-O-tetradecanoylphorbol 13-acetate (TPA) but not with dibutyryl cAMP. TPA also attenuated AII responses in staurosporine-untreated control oocytes. These results suggest that staurosporine suppresses the desensitization of endogenous AII receptors in oocytes by blocking protein kinase C (PKC), and the desensitization is likely to be due to phosphorylation by PKC of the receptors or the molecules comprising an AII receptor complex.
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PMID:Desensitization of endogenous angiotensin II receptors in Xenopus oocytes: a role of protein kinase C. 165 20

Entamoeba histolytica cells secrete electron-dense granules (EDGs) that have collagenase activity. To study the possible involvement of calmodulin (CaM) on EDG secretion, the effect of several CaM antagonists (TFP, R24571, W-7, W-5, dibucaine and DL-propranolol) was tested on this cellular function. Except for W-5 and dibucaine, the rest of these compounds inhibited EDG secretion. Transmission electron microscopy of collagen-activated trophozoites showed numerous EDGs located in or near the surface membrane. In contrast, trophozoites incubated with TFP showed no EDGs. Protein kinase C inhibitors (H-7, ML-9) had no effect on EDG secretion, suggesting that CaM antagonists acted by selectively inhibiting CaM. These results suggest that a CaM-dependent process is involved in EDG secretion.
Mol Microbiol 1991 Jul
PMID:Possible role of calmodulin in the secretion of Entamoeba histolytica electron-dense granules containing collagenase. 165 40

Insulin induces a rapid activation of p21ras in NIH 3T3 and Chinese hamster ovary cells that overexpress the insulin receptor. Previously, we suggested that p21ras may mediate insulin-induced gene expression. To test such a function of p21ras more directly, we studied the effect of different dominant inhibitory mutants of p21ras on the induction of gene expression in response to insulin. We transfected a collagenase promoter-chloramphenicol acetyltransferase (CAT) gene or a fos promoter-luciferase gene into NIH 3T3 cells that overexpressed the insulin receptor. The activities of both promoters were strongly induced after treatment with insulin. This induction could be suppressed by cotransfection of two inhibitory mutant ras genes, H-ras(Asn-17) or H-ras(Leu-61,Ser-186). In particular, insulin-induced activation of the fos promoter was inhibited completely by H-ras(Asn-17). These results show that p21ras functions as an intermediate in the insulin signal transduction route leading to the induction of gene expression.
Mol Cell Biol 1991 Dec
PMID:Two dominant inhibitory mutants of p21ras interfere with insulin-induced gene expression. 165 21


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