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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human colon cancer cell line Caco-2 undergoes spontaneous enterocytic differentiation during growth, and expresses a number of brush-border-membrane-associated hydrolases typical of a differentiated phenotype. Among these are alkaline phosphatase, dipeptidyl peptidase IV and sucrase-isomaltase (sucrase, EC 3.2.1.48). Neutral endopeptidase 24.11 [EC 3.4.24.11, neprilysin (NEP)] is another abundant protease of normal enterocytes but its presence in Caco-2 cells has not been fully documented yet. In this paper, we show that Caco-2 cell extracts hydrolyse tritiated [D-Ala2Leu5]enkephalin with a Km of 180 microM, very close to the value obtained for the NEP present in the rabbit kidney (118 microM). Western-blot analysis of brush-border membranes purified from post-confluent cells revealed a protein with an apparent molecular mass of 94000 Da similar to that of the rabbit kidney NEP. The amount of enzyme in cell extracts increased as a function of the age of the culture, indicating that NEP expression is correlated with the degree of cell differentiation as is also the case for sucrase and dipeptidylpeptidase IV (DPP-IV). Binding of a radiolabelled antibody to Caco-2 cell monolayers grown on semi-permeable filters indicated that 95% of NEP molecules present at the cell surface are on the apical side. Immunocytochemical and flow cytometric analysis of intact and permeabilized cells were also used to investigate the presence of NEP and DPP-IV at the surface of Caco-2 cells. Whereas DPP-IV staining appeared to be homogeneous throughout the entire cell population, NEP-related fluorescence exhibited a bimodal distribution which indicates an uneven expression of the protein at the cell surface. Permeabilization of monolayers with saponin before staining restored a labelling pattern for NEP similar to the one obtained for DPP-IV. This suggests that although DPP-IV and NEP follow similar patterns of expression when enzymic activities are measured on whole-cell extracts, targeting of these brush-border proteins to the cell surface appears to be regulated in different ways.
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PMID:Polarized distribution of neutral endopeptidase 24.11 at the cell surface of cultured human intestinal epithelial Caco-2 cells. 136 26

To investigate the biosynthetic basis for the mosaic expression of brush border enzymes in confluent Caco-2 cells, a human colon carcinoma cell line exhibiting characteristics of adult small intestinal enterocytes, we have obtained a series of clones differing markedly in their growth rates, amounts of transforming growth factor-alpha/epidermal growth factor-like activity released into the culture medium, and sucrase-isomaltase (SI) activity. Other intestinal markers (aminopeptidase N, dipeptidylpeptidase IV, lactase, alkaline phosphatase and 'crypt cell antigen') displayed a much more limited variability in expression, suggesting that the Caco-2 cell clones we have obtained did not differ in their overall ability to differentiate. Immunofluorescence staining, metabolic labelling with radioactive methionine and hybridization analysis of SI mRNA abundance were used to investigate SI synthesis and its regulation in clones endowed with low, intermediate or high sucrase activity. The results obtained have demonstrated heterogeneous SI expression, even in clonal cell lines, and a negative correlation between SI expression and growth factor concentrations in the culture medium, suggesting an autocrine regulation of cell proliferation and differentiation in confluent Caco-2 cells. Pulse-chase experiments using the two clones endowed with the lowest and highest levels of SI activity, followed by immunoprecipitation of labelled SI with epitope-specific antibodies and SDS/PAGE analysis, suggested that both transcriptional and post-translational mechanisms play a role in the regulation of SI expression in intestinal cells.
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PMID:Clonal analysis of sucrase-isomaltase expression in the human colon adenocarcinoma Caco-2 cells. 176 23

To investigate the role and mechanism of action of epidermal growth factor (EGF) in the intestinal epithelium, we have studied its influence on proliferation and differentiation of Caco-2 cells, a human colon adenocarcinoma cell line exhibiting several characteristics of adult small intestinal enterocytes. A clone of Caco-2 cells synthesizing minimal amounts of transforming growth factor-alpha (TGF-alpha)/epidermal growth factor (EGF)-like activity was used in these studies. Cells grown in the presence of 20-200 ng EGF/ml exhibited increased DNA synthesis and proliferation; formation of morphologically poorly differentiated multilayers was observed at 200 ng EGF/ml. At all concentrations tested EGF produced a significant and marked reduction in sucrase activity, whereas other brush-border enzymes (aminopeptidase N, alkaline phosphatase, dipeptidylpeptidase IV) were only marginally affected. EGF influenced sucrase expression at two different levels. At 20 ng/ml, it affected primarily sucrase-isomaltase processing in the endoplasmic reticulum and/or increased its degradation. At 200 ng EGF/ml, a significant and marked reduction in sucrase-isomaltase mRNA levels and biosynthesis was observed. These results demonstrated that EGF has important and selective effects on Caco-2 cell proliferation and differentiation and may affect different cellular activities depending on its concentration.
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PMID:Inhibition of sucrose-isomaltase expression by EGF in the human colon adenocarcinoma cells Caco-2. 176 18

1. Change in digestive enzyme activities determined biochemically in brush-border membrane vesicles and cytochemically in isolated villi of lamb proximal intestine has been related to diet, intestinal structure and rumen development during the first 10 weeks of postnatal life. 2. Lactase activity halved, dipeptidylpeptidase IV activity doubled and aminopeptidase N and alkaline phosphatase activities remained constant during this period of development. Maintaining lambs on a milk replacer diet for 5 weeks after birth had no effect on this pattern of postnatal change in digestive enzyme activities. 3. Structural changes accompanying these selective effects on enzyme expression included a halving of villus height and a doubling of villus width. Villus surface area remained unaffected by these changes in height and width of villi. Crypt depth doubled during the first 10 weeks of postnatal life. Maintaining lambs on a milk replacer diet for 5 weeks did not affect this pattern of change in intestinal structure. 4. It appears from these results that postnatal decrease in lactase and increase in dipeptidylpeptidase IV activities are not regulated by factors such as diet, rumen development, or changes in intestinal structure. Attention is drawn to differences encountered between these results and a postnatal modification of glucose transport which clearly is dependent on diet.
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PMID:Postnatal development of lamb intestinal digestive enzymes is not regulated by diet. 190 59

Localization of dipeptidylpeptidase IV was studied in the spinal cord meninges and peripheral nerve coverings of fetal and postnatal rats. In the same sections, the localization of alkaline phosphatase was monitored. In the prenatal period, dipeptidylpeptidase (DPP) IV activity in the differentiating meninges appeared at the time of cerebrospinal fluid spaces formation (on day 16 in the cervical region and on day 18 in the lumbar region). In adult animals DPP IV was found in cells of those meningeal lamellae which delineated the cerebrospinal fluid spaces (the outer, intermediate and inner lamellae), in the perineurium, in Schwann cells and in some fibroblasts of the bulk of dura mater. It is suggested that DPP IV plays a role in the metabolism of neuropeptides by their interaction with cerebrospinal fluid. Alkaline phosphatase activity was detectable earlier than DPP IV activity. Positivity was first observed in some cells of the meninx primitiva and, later on, in the ectomeninx and also in the differentiating endomeninx where it disappeared postnatally. The developing ectomeninx exhibited activities of both enzymes. Alkaline phosphatase occupied its external layers, while DPP IV was localized in its inner layers. This enzymatic heterogeneity of the ectomeningeal layers suggests that the ectomeninx gives rise not only to dura mater (which in adult animals exhibits alkaline phosphatase activity) but also to the outer arachnoid layer (positive for DPP IV in adult rats).
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PMID:Localization of dipeptidylpeptidase IV and alkaline phosphatase in developing spinal cord meninges and peripheral nerve coverings of the rat. 197 Feb 18

In the present investigation the localization and activity of alkaline, neutral, and acid hydrolases of the thymus were studied during development of rats and mice and of various adult species using histochemical methods. If different procedures of tissue pretreatment were employed, several inhibition effects and morphological as well as enzyme histochemical artifacts occurred dependent on the mode of tissue pretreatment. After embedding in glycol methacrylate, sections of the thymus showed a better structural preservation than cryostat sections but were accompanied by a drastic decrease of activity and low localization quality of the final reaction products especially in the case of protease studies with 4-methoxy-2-naphthylamine peptides as substrates. Smears of thymic cells facilitated the allocation of enzymes to mobile or fixed cells in the stroma of the thymus. The perivascular localization of aminopeptidase M could only be shown with combined techniques. In comparison, primarily the proteases yielded information on the thymic stroma and in this context especially on the epithelial reticular cells and the stroma proper but also on thymocytes (lymphocytes) and enabled a species-dependent subdivision of the thymic reticulum already in the light microscope. Enzyme histochemically the development of the rat and mouse thymus could be subdivided into an early period and perinatal (pre- and postnatal) period of functional differentiation. Morphological (proliferation of cortical lymphocytes) and enzyme histochemical changes (disappearance of dipeptidylpeptidase IV, significant loss of alkaline phosphatase activity and beginning activity increase of aminopeptidase M) occurred primarily at the transition from the early to the prenatal period. During the postnatal phase, a significant activation of lysosomal enzymes in the thymic medulla and general enzymatic differentiation of the cortical epithelial reticular cells were found. Species differences and species similarities for the respective enzymes and their localization as well as for the thymic cells were noticed for adult rats, mice, guinea-pigs, hamsters, and marmoset monkeys. Differences were true especially for the thymocytes; less species differences were seen for the epithelial reticular cells; capsular and perivascular connective tissue and the macrophages behaved rather similarly. Species-independently certain medullary epithelial reticular cells showed high and typically localized alkaline phosphatase activities and species-dependently also high activities of neutral hydrolases.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Hydrolase histochemistry of the thymus: development and species variations]. 250 44

Vascular bed and its relationship to differentiating muscular tissue was studied in a set of 104 upper limbs of human embryos and foetuses, gradually increasing from 10 to 120 mm C-R length. Knowledge obtained on the ontogeny of vascular bed was supplemented by findings in 75 limbs of adults treated by preparation technique. Embryonic and foetal material was treated histochemically a--to demonstrate vascular bed reaction for alkaline phosphatase (AP), ATPase, and dipeptidylpeptidase IV (DPP IV), b--to study differentiating muscular tissue for enzyme--ATPase and tetrazoliumreductase (NaDH2, c--to distinguish muscular tissue elements with toluidine blue staining for degree of maturity. Observations concerned several items, namely a--the ontogeny of main arterial trunks in the forearm and hand, b--muscle fibre type differentiation in antebrachial muscular primordia, c--formation of vascular bed as related to differentiating muscular tissue in the forearm and hand. Therefore our results are grouped as follows: ad a--Arterial trunks differentiate along with other limb structures in 12-18 mm C-R length embryos. Thus in embryos above 18 mm C-R length antebrachial and hand trunks are fully formed. Vascular trunks differentiate from deep vascular network via gradual reduction and magistralization in conformity with the general laws of haemodynamics. All arterial trunks forming in the limb during the ontogeny branch off the original axial artery in regio cubiti. In a. radialis trunk it has been ascertained that this blood vessel does not originate from a. brachialis superficialis, as generally reported, but its formation conforms to the same general principles as blood vessel trunks. So it branches off the original axial artery, as other trunks do. A. mediana formed during vascular trunks differentiation later in the ontogeny does not obliterate but changes into the constant a. comitans n. mediani. ad b--First involved in differentiation in antebrachial muscular primordia are the "fast" type fibres (according to Peter et al., 1972) (fast glycolytic-FG-type fibres followed by fast oxidative glycolytic-FOG-type fibres) in 27-30 mm C-R length embryos. "Slow" type fibres (slow oxidative-SO-type fibres) may not be demonstrated histochemically in antebrachial muscles earlier than 45 mm C-R length foetuses. The maturity of muscular elements may be demonstrated by staining with toluidine blue on cytoplasm basophilia of cells. Sarcolytic myotubes in muscular primordia histochemically display typical features which distinguish them markedly from other differentiating muscle fibres.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Blood vessel ontogeny in upper extremity of man as related to developing muscles. 288 17

Twenty human colon carcinoma cell lines were studied for their ability to develop some of the characteristics of the normal intestinal epithelium, e.g., epithelial polarity, presence of the actin-binding protein villin, or the occurrence of an enterocytic differentiation either when cultured under standard conditions, as for Caco-2 cells, or when grown in a glucose-free medium, as for HT-29 cells. Except for the regular presence of villin, which can be considered a marker of the colonic origin of the cells, the cell lines of this study could be classified into four types with regard to their differentiation characteristics. In type 1 (only one cell line, i.e., Caco-2) the cells undergo spontaneously an enterocytic differentiation characterized by a polarization of the cell layer with the formation of domes and the presence of an apical brush border the membrane of which is endowed with hydrolases such as sucrase-isomaltase, lactase, amino-peptidase N, dipeptidylpeptidase IV and alkaline phosphatase. In type 2 (three cell lines: HT-29, HCT-EB, and HCT-GEO) the cells are undifferentiated when grown in the presence of glucose but undergo an enterocytic differentiation when grown in the absence of glucose. In type 3 (eight cell lines: HCT-GLY, HCT-FET, HCT-FRI, HCT-CBS, HCT-ALA, Co-115, HRT-18, and SW-1116) the cells are organized into a polarized monolayer with the formation of domes but without any enterocytic differentiation characteristics, whatever the culture conditions. In type 4 (eight cell lines: HCT-116a, HCT-R, HCT-RCA, HCT-Moser, HCT-8R, SW-480, LS-174T, and Vaco-9P) the cells are organized into a multilayer without any feature of epithelial polarity or enterocytic differentiation, whatever the culture conditions.
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PMID:Epithelial polarity, villin expression, and enterocytic differentiation of cultured human colon carcinoma cells: a survey of twenty cell lines. 334 66

Yolk sacs from Callithrix jacchus were investigated light and electron microscopically as well as by qualitative light microscopic enzyme histochemistry on days 35 to 126 of gestation. The thin yolk sac wall of the early stages (day 35-41) consists of the cuboid, endodermal epithelium, the mesothelium of the exocoelom and some interposed blood vessels. The inner endodermal surface is rather smooth. At later stages, the epithelium becomes highly prismatic and forms folds which are lined by a mesenchyme and blood vessels. Microvilli and a small number of endocytotic vesicles are observed at the apices of the epithelial cells, which are interconnected by gap junctions, desmosomes and interdigitations. The cytoplasm of the epithelial cells is characterized by a well-developed rough endoplasmic reticulum, a large Golgi apparatus and glycogen deposits. Four different membrane-bordered types of inclusions can be distinguished in the cytoplasm of the epithelial cells: The type I and II inclusions are considered as secretion granules. Their increase and their localization in the cavities of the endoplasmic reticulum at later stages are ascribed to an inhibition of the intracellular transport at the onset of involution. The type III and IV inclusions may represent lysosomes and related organelles. Bile capillary-like spaces exist between the epithelial cells. The basement membrane is incomplete below the epithelium and absent around the capillaries, the endothelium of which is porous in certain areas. Aminopeptidase M is highly active in the plasmalemma and the bile capillary-like structures of the epithelium, dipeptidylpeptidase IV in the mesothelium and alkaline phosphatase in the blood vessel endothelium. Other membrane hydrolases are absent. Acid proteases, glycosidases, non-specific phosphatases and non-specific esterases can be detected stage-dependently with moderate to high activities in the yolk sac epithelium. Compared with other organs, the yolk sac structure and hydrolase equipment are similar to those of the liver and may, therefore, have similar functions, e.g. synthesis and secretion of proteins. In addition, however, the yolk sac epithelium might also be involved in resorptive processes of material from the lumen followed by lysosomal digestion. The Callithrix jacchus yolk sac starts involution on day 80 of gestation by disintegration of the cells. On day 100, this process is completed. The stage of involution which is late in comparison with other primates, e.g. man and Rhesus monkey, is ascribed to the strongly delayed development of Callithrix jacchus.
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PMID:Ultrastructure and hydrolase cytochemistry of the developing marmoset yolk sac. 392 47

The lymphocytes of the rat thymus can be grossly differentiated by their cell membrane-bound proteinases. Subcapsular thymocytes lack aminopeptidase A (APA) and AMP and gamma-glutamyltranspeptidase (GGT). Cortical thymocytes show a high activity of APA but no APM and no GGT. Medullar thymocytes possess a high GGT and APM activity but are free of APA. Under Mg deficiency, the APA-negative subcapsular thymocytes are reduced. In lymphoma and beginning lymphoma, APA, APM and GGT are absent. In lymphoma, the alkaline phosphatase activity is increased. Differences are found for dipeptidylpeptidase IV (DPP IV). In some lymphoma, its activity is reduced, in others the DPP IV activity is increased.
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PMID:Enzyme histochemistry of malignant T cell lymphoma due to chronic magnesium deficiency in rats. 614 41


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