Immunolocalization of extracellular matrix components during organogenesis in the human small intestine

Abstract

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 antibodies 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.

Complex patterns of expression suggest extensive roles for the α2β1 integrin in murine development

“…la), also express the laminin B2 mRNA (Senior et al, 1988). In addition, type IV collagen has been immunolocalized pericellularly around the mesenchymal cells of the lamina propria (Simon-Assmann et al, 1986;Beaulieu et al, 1991). Expression of a2 mRNA and protein was also found in the developing lens beginning at E12.5 to full gestation (Fig.…”

Differential expression of laminin isoforms and α6‐β4 integrin subunits in the developing human and mouse intestine

“…In the mature intestine, gradual changes in the composition of the extracellular matrix (Quaroni et al, 1978;Simon-Assmann et al, 1986;Aufderheide and Ekblom, 1988;Weiser et al, 1990;Beaulieu et al, 1991) along the crypt to villus axis could mediate the continuous dynamic epithelial cell migration and differentiation. For example, we have previously shown that laminin B chains are homogeneously distributed in the crypt and villus basement membrane of adult rodent intestine, whereas the A chain was restricted to the crypt zone (Simo et al, 1991).…”

Is it feasible to control pathogen infection by competitive binding of probiotics to the host?

“…31 ECM in the lamina propria of the GIT is a complex of glycosaminoglycans and ECM glycoproteins, including collagen, fibronectin, laminin, elastin, thrombospondin, tenascin, and nidogen, secreted by epithelial and mesenchymal cells. 32,33 Cells are surrounded by ECM and hence embedded in the tissue, giving physical strength and flexibility, and furthermore, ECM modulates differentiation, migration, polarity, proliferation, and vitality of the cells, by stimulating cell signaling pathways via proteoglycan-cytoskeletal integrin-growth factor receptor axis. 34 Under physiologically normal conditions, the major part of ECM underlie the epithelial cells in the GIT, but the localized exposure of ECM to the intestinal lumen occurs transiently by cell shedding during the turnover.…”