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  • 1
    Electronic Resource
    Electronic Resource
    Immunolocalization of extracellular matrix components during organogenesis in the human small intestine (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 363-369 
    Details
    ISSN: 1432-0568
    Keywords: Intestine ; Sucrase-isomaltase ; Heparan sulfate proteoglycan ; Type-IV collagen ; Laminin ; Fibronectin ; Tenascin ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The expression and distribution of several major extracellular matrix macromolecules were investigated at the epithelial-mesenchymal interface of the human fetal small intestine from 8 to 20 weeks of gestation. Localization of heparan sulfate proteoglycan, type-IV collagen and laminin, three basement membrane components, as well as fibronectin and tenascin, were assessed by indirect immunofluorescence staining on cryostat sections, and correlated to morphogenesis and epithelial cell differentiation. Basement membrane components and fibronectin were all detected as early as 8 weeks (a time when the epithelium is still stratified and does not express sucrase-isomaltase). Tenascin appeared only after short villi had developed (around 10 weeks) and was restricted to the connective tissue at the tip of villus rudiments. At 18 weeks, well-formed villi and crypts were apparent. The antibody against heparan sulfate proteoglycan stained exclusively the epithelial basement membrane. Anti-type-IV collagen and anti-laminin anti-bodies stained the epithelial basement membrane and also cellular and fibrillar structures in the lamina propria. Fibronectin was found uniformly distributed over the lamina propria except in the upper third position of the villus core. On the contrary tenascin was mainly localized in the stroma at the tip of the villi. Staining for tenascin was also detected at the epithelial-mesenchymal interface of the villus and in the mesenchyme immediately surrounding budding crypts. These results provide basic data concerning the development of the human gut, and suggest that extracellular matrix components could be involved in the remodelling process of the intestinal mucosa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196837
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  • 2
    Electronic Resource
    Electronic Resource
    Relationship between tenascin and α-smooth muscle actin expression in the developing human small intestinal mucosa (1993)
    Springer
    Anatomy and embryology 188 (1993), S. 149-158 
    Details
    ISSN: 1432-0568
    Keywords: Tenascin ; Extracellular matrix ; Smooth muscle cell ; Myofibroblasts ; α-Actin ; Human fetal intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of tenascin (Tn) and α-smooth muscle actin (α-SMA) was analyzed in the developing and adult human small intestine by means of double immunofluorescent staining with specific antibodies. By 7 weeks of gestation, the gut anlage has a simple tubular shape and is formed of a stratified undifferentiated epithelium surrounded by a poorly organized mesenchyme. Both Tn and α-SMA were found exclusively at the periphery of the tissue, corresponding to the presumptive muscularis propria. By 9 weeks, villus rudiments had formed but Tn and α-SMA remained restricted to the muscularis propria. Tn was first detected in the mesenchyme at 11 weeks. By 13 weeks, a preferential distribution of Tn in the subepithelial region of the mesenchyme was readily observed while α-SMA was still absent. From this stage to 20 weeks, Tn gradually concentrated in this region that, as determined by α-SMA detection, corresponded to the future muscularis mucosa area. As shown by double staining of Tn and α-SMA, deposition of Tn also preceded the appearance of the other α-SMA-expressing cells in the mucosa. These observations suggest that Tn could have a role in the differentiation of intestinal contractile cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186248
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  • 3
    Electronic Resource
    Electronic Resource
    Basement membrane formation and re-distribution of the β1 integrins in a human intestinal co-culture system (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 235 (1993), S. 567-576 
    Details
    ISSN: 0003-276X
    Keywords: Extracellular matrix ; Integrins ; Fibroblasts ; Caco-2 cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have developed a co-culture system suited for the study of epithelial-mesenchymal interactions in the human fetal small intestine. As the epithelial component of this model, we used the human intestinal cell line Caco-2 that is unique in its property to differentiate in vitro into a mature fetal enterocyte-like cell type. A sheet of human intestinal mesenchymal cells, which we derived from an 18-week-old fetus, was used as mesenchymal element. Expression and distribution of cell-specific markers (cytokeratin 18 and dipeptidyl peptidase IV), major basement membrane components, and β1 integrins were analyzed. In 14-day co-cultures, Caco-2 cells formed a cytokeratin 18-positive epithelial-like sheet covering the vimentin-positive HIM cell layers. As assessed by brush border dipeptidyl peptidase IV expression, co-cultured Caco-2 cells achieved cytodifferentiation as when cultured on plastic. A complete deposition of all known major human fetal intestinal basement membrane components occurred at the Caco-2/HIM interface. Type IV collagen and tenascin were produced from the mesenchymal compartment, whereas laminin and fibronectin were contributed by both cell types. Interestingly, synthesis and deposition of basement membrane heparan sulfate proteoglycan were exclusively observed in co-cultures, suggesting modulation of epithelial expression of this molecule by HIM cells. Finally, we observed that epithelial integrin-β1 chains redistributed at the basal domain of co-cultured Caco-2 cells. Taken to gether, these observations indicate that the Caco-2/HIM co-culture model is a valuable system to study in vitro human basement membrane formation in the context of intestinal epithelial-mesenchymal interactions. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092350409
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  • 4
    Electronic Resource
    Electronic Resource
    Immunolocalization of a mesenchymal antigen specific to the gastrointestinal tract (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 240 (1994), S. 358-366 
    Details
    ISSN: 0003-276X
    Keywords: Gallbladder ; Stomach ; Small intestine ; Colon ; Extracellular matrix ; Mouse ; Pre-embedding ; Immunolabeling ; Immunofluorescence ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The aim of the present study was to localize, at the fine structural level, a protein found by indirect immunofluorescence to be associated with the mesenchymal tissue (1) closely applied to the intervillus epithelium before the formation of intestinal crypts in the mouse fetus and (2) around intestinal crypts during and after their formation.Methods: We use a pre-embedding immunolabeling technique for extracellular matrix molecules, and a monoclonal antibody (Mab) directed against antigen MIM-1/130.Results: Immunofluorescence disclosed the presence of antigen 1/130 in the connective tissue closely applied to the epithelium of the gallbladder, pyloric glands, and intestinal and colonic crypts in adult mice. The antigen was absent in all salivary glands, kidney, liver, lung, spleen, and pancreas. At the fine structural level, gold particles in positive organs were associated with the interstitial matrix around collagen fibrils underneath the epithelia; gold particles were completely absent in the basement membranes. In the small intestine, labeling was seen only around crypts from cell position 1 up to the crypt-villus junction; it was totally absent under the villus epithelium. In order to confirm this particular localization in vivo, Mab 1/130 was administered orogastrically to 9-day-old mice: after 3 hours the antibody was found lining the immediate periphery of duodenal crypts as seen by indirect immunofluorescence. In control animals, an anti-mouse laminin Mab of the same subclass as Mab 1/130 was orogastrically fed using the same protocol: basal laminae were labeled under the epithelium of duodenal villi and crypts and also in the lamina propria, with a decreasing gradient from the top of the villi to the bottom of the crypts.Conclusion: These observation indicate that the extracellular matrix associated with the epithelium of pyloric glands, of intestinal and colonic crypts, and of gallbladder contains a new antigen whose function remains to be determined. The neonatal mouse hence constitutes a good model to study the role of extracellular matrix components in determining organ differentiation in vivo. © 1994 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092400308
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  • 5
    Electronic Resource
    Electronic Resource
    Appearance and distribution of laminin a chain isoforms and integrin α2, α3, α6, β1, and β4 subunits in the developing human small intestinal mucosa (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 242 (1995), S. 242-250 
    Details
    ISSN: 0003-276X
    Keywords: Laminin ; Merosin ; Integrin ; Human fetus ; Villus ; Crypts ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Laminin, a major component of basement membranes, is well known in its classical heterotrimeric form (B1-A-B2) to regulate diverse biological functions, including cell polarization and differentiation. However, the role of merosin, a laminin-like molecule in which an M chain is substituted for its homologous A chain, remains largely unknown.Methods: In the present study, we analyzed by indirect immunofluorescence the expression and distribution of these four laminin chains as well as the integrins α2β1, α3β1,α6β1, and α6β4, four potential recptors, at the epithelial-mesenchymal interface of the developing human small intestine, with a panel of specific monoclonal antibodies.Results: Beginning at 7 weeks of gestation and throughout mucosal organogenesis, the B1 and B2 chains were uniformly detected at the epithelial basement membrane. The A chain also was detected beginning at 7 weeks, and its distribution at the basement membrane remained uniform throughout villus (9+ weeks) and crypt (16+ weeks) formation. In contrast, M chain expression was not observed until 16 weeks; between 16 and 20 weeks, it was exclusively associated with the base of epithelial cells that comprised the forming crypts. Integrins α6β1 and α6β4, as determined by their subunit immunolocalization, appeared to be expressed by all enterocytes from 7 to 20 weeks. In contrast, the expression of the α2β1 and α3β1 integrins was found time- and site-restricted. The α2 subunit was predominantly detected in the epithelial cells of the intervillous area and its derivative, the crypt, whereas the α3 subunit was strongly expressed by all epithelial cells except those located at the bottom of 19-20-week-old crypts.Conclusions: Taken together, these observations demonstrate that both compositional changes in the basement membrane and differential expression of receptors occur during human intestinal organogenesis, suggesting that epithelial cell-matrix interactions play a role during development. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092420214
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  • 6
    Electronic Resource
    Electronic Resource
    CCAAT/Enhancer binding protein isoforms expression in the colon of neonatal mice (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 204 (1995), S. 66-76 
    Details
    ISSN: 1058-8388
    Keywords: C/EBP ; Colon ; Development ; Gene expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Development of murine proximal colon follows a complex pattern of morphological and functional differentiation. Molecular mechanisms and factors responsible for colonspecific gene expression remain to be established. In an attempt to identify some of these factors, we examined the expression of the α, β, and δ isoforms of the CCAAT/enhancer binding protein (C/EBP) transcription factor gene family during murine colon development. Whereas C/EBPα mRNA levels are reduced during the third post-natal week, C/EBPα 42 and 30 kD proteins levels decrease between post-natal days 8 and 21. C/EBPβ mRNA levels increase between post-natal days 4 and 8 and remain constant subsequently, in contrast to a decrease in C/EBPβ protein levels between post-natal days 11 and 15. C/EBPδ mRNA levels increase gradually while C/EBPδ protein levels show variations during post-natal development. Changes in C/EBP DNA binding activity coincides with modifications in C/EBP isoforms expression. By indirect immunofluorescence, we show restriction of C/EBPα expression to differentiated surface epithelial cells during crypt formation. C/EBPβ is predominantly nuclear with some cytoplasmic staining at all developmental stages. C/EBPβ and δ are both predominantly nuclear in crypt and differentiated surface epithelial cells, as well as in various cells of the lamina propria and muscular layers. Thus, specific C/EBP isoforms are differentially regulated during murine colon post-natal development. Differential C/EBP isoforms pattern of expression suggests a role for these transcription factors in colon-specific gene expression during development. © 1995 wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1002040109
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  • 7
    Electronic Resource
    Electronic Resource
    Regulated expression of the integrin α9β1 in the epithelium of the developing human gut and in intestinal cell lines: Relation with cell proliferation (1998)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 71 (1998), S. 536-545 
    Details
    ISSN: 0730-2312
    Keywords: intestinal epithelium ; cell growth ; cell differentiation ; HIEC ; Caco-2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The integrin α9β1 is one of the recently identified integrins whose expression is restricted to specialized tissues. Its exact function is still unknown. In the present study, we have analyzed the expression of the α9 subunit in human fetal and adult small intestinal and colonic epithelia as well as in intestinal cell lines by indirect immunofluorescence, immunoprecipitation, Western blot, and Northern blot. In intact tissues, the antigen was restricted to the basolateral domain of epithelial cells in intestinal crypts at the fetal stage and was absent in the adult. The α9β1 integrin was also detected in the intestinal cell lines HIEC-6 and Caco-2/15. The presence of α9β1 in HIEC-6 was found to be consistent with their proliferative crypt-like status. In Caco-2/15 cells, the integrin was present at high levels in proliferating cells but was downregulated when cells cease to grow and undertake their differentiation. EGF treatment, which is known to maintain Caco-2/15 cells in a proliferative state, resulted in higher levels of α9 as compared to control cells. Taken together, these observations suggest a relation between integrin α9β1 expression and proliferation in human intestinal cells. J. Cell. Biochem. 71:536-545, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Apolipoproteins in human fetal colon: Immunolocalization, biogenesis, and hormonal regulation (1998)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 70 (1998), S. 354-365 
    Details
    ISSN: 0730-2312
    Keywords: human fetal colon ; apolipoprotein A-I, A-IV, B-48, B-100 ; hydrocortisone ; insulin ; epidermal growth factor ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The present investigation aimed at defining the localization of apolipoproteins (apo) A-I, A-IV, B-48, and B-100 along the crypt-villus axis of the human fetal colon, their biogenesis during gestation, and their hormonal regulation. Using immunofluoresence, the distribution of apo A-I and A-IV appeared as a gradient, increasing from the developing crypt to the tip of the villus. On the other hand, apo B-100 staining was found in the crypt and the lower mid-villus region with varying intensities in the upper villus cells, while the 2D8 antibody which recognizes both apo B-100 and B-48, revealed uniform staining along the crypt-villus axis. Apolipoprotein synthesis, determined by [35S] methionine labeling, immunoprecipitation, and SDS-PAGE showed a predominance of apo A-IV (53%), followed by apo A-I (23.9%), apo B-48 (13.4%), and apo B-100 (9.7%). The synthesis of each apolipoprotein was significantly modulated by hydrocortisone, insulin and epidermal growth factor (EGF). Apart from a decrease in apo B-100 exerted by EGF and a reduction in apo A-I resulting from the addition of insulin, the other apolipoproteins were all enhanced. Our data confirm that the fetal colon has the capacity to synthesize apolipoprotein A-I, A-IV, B-48, and B-100 and establish that their synthesis are modulated by hormonal and growth factors known to be involved in the regulatory mechanism of the functional development of human jejunum. J. Cell. Biochem. 70:354-365, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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