Interepithelial signaling with nephric duct is required for the formation of overlying coelomic epithelial cell sheet

Abstract

In most organs of the body, epithelial tissues are supported by their own basement membrane and underlying stroma, the latter being regarded as a complex of amorphous cells, extracellular matrices, and soluble factors. We demonstrate here that an epithelial tube can serve as a component of stroma that supports the formation of epithelial cell sheet derived from a different origin. During development of the mesonephros in chicken embryos, the intermediate mesoderm (IMM), which contains the Wolffian duct (WD) and its associated tubules, is overlain by a sheet of epithelial cells derived from lateral plate (coelomic) mesoderm. We describe that in normal embryos, epitheliogenesis of IMM tubes and the adjacent coelomic cell sheet proceed in a coordinated manner. When the WD was surgically ablated, the overlying coelomic epithelium exhibited aberrant morphology accompanied by a punctated basement membrane. Furthermore, the WD-ablated coelomic epithelium became susceptible to latent external stress; electroporation of Rac1 resulted in epithelial-to-mesenchymal transitions (EMTs) within the coelomic epithelium. The distorted coelomic epithelium was rescued by implanting fibronectin-producing cells in place of the WD, suggesting that fibronectin provided by WD has an important role acting interepithelially. This notion was corroborated further by directly visualizing a translocation of EGFP-tagged fibronectin from fibronectinproducing to -receiving epithelia in vivo. Our findings provide a novel insight into interepithelial signaling that also might occur in adult tissues to protect against EMT and suggest a possible new target for anticancer therapeutic strategy.epithelialization | kidney development | extracellular matrix | metastasis | organogenesis

Neural crest cell-autonomous roles of fibronectin in cardiovascular development

“…However, recent in vivo studies suggest that in addition to paracrine functions (Yoshino et al, 2014), Fn1 could also signal in a cell-autonomous manner (Cseh et al, 2010;Liu et al, 2010;Serres et al, 2014;Stenzel et al, 2011). By using genetic and cell biological approaches, the studies reported in this paper are the first to demonstrate the requisite, cell-autonomous role of Fn1 in the regulation of cardiovascular development.…”

Early formation of the Müllerian duct is regulated by sequential actions of BMP/Pax2 and FGF/Lim1 signaling

“…Interplay between the WD and the CE has also been reported in the nephric region at more posterior levels (18th-22nd somites) (Yoshino et al, 2014). In this report, the authors showed that in the absence of the WD, the overlying CE fails to undergo proper epithelialization, and also that these WD-CE interactions are mediated by fibronectin produced by the WD.…”

Preformed Wolffian duct regulates Müllerian duct elongation independently of canonical Wnt signaling or Lhx1 expression

“…Other possibilities include cell-cell contacts, instead of soluble factors, considering the close proximity between the Müllerian and Wolffian ducts. Indeed, a role of fibronectin in Wolffian duct formation was reported in chick embryos (Yoshino et al, 2014). According to the GUDMAP database, integrin b7 is expressed in the Müllerian duct, while nephronectin is expressed in the Wolffian duct.…”