Localization and expression of fibronectin during mouse decidualization in vitro: Mechanisms of cell:matrix interactions

Abstract

During implantation, the embryonic trophoblast aggressively invades the uterine stroma. The resulting uterine reaction, decidualization, involves differentiation of new cell morphologies and remodeling of the extracellular matrix. This creates an environment that first permits invasion, then controls this invasion to allow the establishment of the placenta. The production, organization, and cellular interactions with the matrix are thought to underlie decidual functions. We have begun a reductional analysis of the components of the decidual matrix, focusing on extracellular fibronectin (FN). Using decidual cell cultures prepared from day 7 implantation sites, the synthesis, extracellular organization, and details of decidual celkFN interaction were studied. Employing immunofluorescence, immunoprecipitation, and dot blot analysis, decidualizing cultures showed a constitutive level of FN synthesis and deposition. The differentiating cells organized extracellular FN in patterns similar to that seen in vivo. The predominant, flattened dendritic decidual cells organized FN in long, thin fibrils. Large, rounded decidual cells, limited to the primary decidual zone in vivo, showed FN limited to punctate membrane patches and short, thick fibrils. Using double labeling techniques, FN expresssion was co-localized with actin microfilament (MF) bundles during the cytoskeletal changes associated with the differentiation of both decidual cell types. The function of MFs in maintaining morphology was demonstrated by cytochalasin B perturbation. Attachment of decidual cells to FN was calcium dependent and gly-arg-gly-asp-ser-pro (GRGDSP) sensitive, with dendritic decidual cells expressing the a5 and PI integrin subunits. This suggests that an integrin system functions to attach decidual MF bundles to extracellular FN. This work shows that during decidual matrix remodeling, constitutive levels of FN are maintained to provide an extracellular framework to stabilize the decidual cytoskeleton and support morphological differentiation of decidual cells.

Contributions from Self-Renewal and Trafficking to the Uterine NK Cell Population of Early Pregnancy

“…Consistent with previous reports (33,47), the proportion of labeled cells in test PBL suspensions was 10 -12% CD56 ϩ , with Ͻ1.5% being CD56 bright . Prelabeling with anti-CD56 (murine IgG1) did not affect the total number of cells bound to uterine tissues at any of the time points (data not shown).…”

“…Recent studies by Kruse et al (42) showed VCAM-1 is restricted to endothelium of the central DB in gd9 mice. While this could account for the ␣ 4 integrin-mediated binding observed in the present study, caution must be used in this interpretation because extracellular matrix is also exposed in the assayed tissue and ␣ 4 integrins bind to fibronectin, a molecule prevalent in mesometrial decidua (47). High level MAdCAM-1 expression has also been reported on mesometrial endothelium in the vascular zone, lateral to the DB in gd9 mice (42).…”

Transcription Factor CCAAT Enhancer-binding Protein β (C/EBPβ) Regulates the Formation of a Unique Extracellular Matrix That Controls Uterine Stromal Differentiation and Embryo Implantation

“…During decidualization, the actin cytoskeleton organizes into short to intermediate filaments that lie parallel to the long axis of the stromal cell (19). The cells transduced with Ad-CTRL showed the expected cytoskeletal rearrangement and appeared flattened and cuboid-shaped, characteristic features of decidualized cells (Fig.…”

“…Previous studies reported abundant expression of laminins, collagen type IV, and fibronectin in stromal compartment of pregnant uteri (9,10). It was also observed that uterine stromal cells cultured in vitro produced a basal lamina-like matrix (18,19). These observations led to the speculation that the stromal ECM microenvironment functionally contributes to the differentiation of uterine stromal cells.…”

Covalent Attachment of Fibronectin onto Emulsion‐Templated Porous Polymer Scaffolds Enhances Human Endometrial Stromal Cell Adhesion, Infiltration, and Function

“…Notably, basal PRL levels in undifferentiated cells (D0) and treated cells were higher in cells seeded on fibronectin-functionalized scaffolds, in line with the known role of fibronectin in providing an extracellular framework that stabilizes the decidual cytoskeleton and functional differentiation. [39,40] Further work will look into optimizing the protocol of seeding more cells onto the scaffold, including the use of basic fibroblast growth factor (bFGF) and TGFβ inhibitors, which enhance proliferation by maintaining cells in a more naïve state. [41,42]…”