Immunolocalization of extracellular matrix proteins and collagen synthesis in first‐trimester human decidua

Abstract

The extracellular matrix (ECM) of first-trimester human decidua was examined with indirect immunofluorescence using affinity-purified antibodies to human collagen types I, III, IV, V, laminin, and fibronectin. In addition, the validity of the classification "mesenchymal-epithelioid" for differentiated decidual cells was addressed using antibodies to the intermediate filament proteins, vimentin, a mesenchymal marker, and keratin, an epithelial marker. Biosynthesis of extracellular matrix components was examined by radiolabeling of decidual explants in culture with 3H-proline, followed by immunoprecipitations of synthesized proteins with collagen type-specific antibodies. Immunofluorescence showed decidual cells are embedded in an extensive network of collagen types I and III, and intracytoplasmic staining suggested synthesis of these collagens by the decidual cells. Collagen type IV and laminin localized in the external lamina which surrounds the differentiated decidual cell, and some fluorescence was evident in the peripheral cytoplasm. Immunoreactive collagen type V was observed in close association with the external lamina and in the peridecidual matrix. Fibronectin localized throughout the decidual ECM and in fibrillar and punctuate patterns in the decidual cell cytoplasm. Differentiated decidual cells retained a "mesenchymal" intermediate filament cytoskeleton containing an abundance of vimentin filaments, but very few, if any, keratin filaments. Collagen types I, III, V, and to a lesser extent, IV, were immunoprecipitated from the medium of decidual explants after 24 hours of culture, demonstrating in vitro synthesis and secretion of these collagens by first trimester human decidua.

Cell Surface Expression of HIP, a Novel Heparin/Heparan Sulfate-binding Protein, of Human Uterine Epithelial Cells and Cell Lines

“…11). As expected, the underlying stroma extracellular matrix also displayed strong expression of the decidual marker, laminin (27), at this time. In contrast, laminin expression was confined to basal lamina in stromal tissue of late proliferative stage uteri.…”

Human endometrial matrix metalloproteinase-2, a putative menstrual proteinase. Hormonal regulation in cultured stromal cells and messenger RNA expression during the menstrual cycle.

“…Decidualized stromal cells produce an extracellular matrix containing types IV and V collagens as well as fibronectin and laminin (45,46). MMP-2 degrades basement membrane collagens (types IV, V), fibronectin (32), and laminin (35) and may be expected to be actively involved in the degradation of extracellular matrix in decidualized endometrial stroma.…”

Matrix metalloproteinases in choriocarcinoma cell lines: A potential regulatory role of extracellular matrix components

“…Among the numerous changes which take place during the decidualization process, extensive modifications of the composition and organization of endometrial ECMs have been well documented (Wewer et al, 1985Kisalus et al, 1987;Aplin et al, 1988;Aplin and Jones, 1989). These modifications include the secretion by decidual cells of a distinct pericellular basement membrane (which contains kaminin, type IV collagen, fibronectin, and heparan sulfate proteoglycans; Wewer et al, 1985;Kisalus et al, 1987;Korhonen et al, 1991;Divers et al, 1995) as well as the remodeling of the decidual interstitial matrix characterized by the disappearance of interstitial collagen VI (which is thought to crosslink fibrils of the major collagens), the reduction in fibril density, and the synthesis of new collagens (Aplin and Jones, 1989;Mylona et al, 1995). Thus, during the first trimester of pregnancy, trophoblast infiltration will take place into a sparsely fibrillar network of several matrix proteins (including laminin, fibronectin, and typesq, -III, -IV, -V collagens) which separates the villous cytotrophoblast cells from the maternal vasculature.…”

“…Our data demonstrate that BeWo cells adhere most efficiently to both fibronectin and type-I and -IV collagens, whereas adhesion of JAr cells was restricted to fibronectin. Since fibronectin is abundant in decidua in locations where trophoblast infiltration occurs Kisalus et al, 1987;Aplin and Jones, 1989;Damsky et al, 1992Damsky et al, , 1993, and may thus provide a transient anchorage for migrating ceils, the strong affinity of these choriocarcinoma cells for fibronectin may be considered as a requirement for an extravillous phenotype (Aplin et al, 1992). However, the differential affinity of these two cell lines for collagens suggests that they could present certain phenotypical similarities with two distinct subpopulations of extravillous trophoblast cells.…”