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TGF‐[beta] Induces Loss of Epithelial Character in Mouse Epicardial Explants
Author(s) -
Austin Anita F.,
Compton Leigh A.,
Barnett Joey V.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a32-c
Subject(s) - explant culture , microbiology and biotechnology , transforming growth factor , in vitro , embryo , transforming growth factor beta , biology , epithelium , kinase , chemistry , medicine , endocrinology , biochemistry , genetics
Epicardial cells in the embryo undergo epithelial‐mesenchymal transformation, invade the myocardium, and differentiate into components of the coronary vasculature. We tested the hypothesis that transforming growth factor β (TGFβ) stimulates loss of epithelial character in mouse epicardial cells. We devised a system for the culture of epicardial explants from E11.5 mouse embryos. By twenty‐four hours after placement of the heart on a collagen gel, epicardial cells were forming an epithelial sheet that was stable for at least an additional 48 hours. The addition of 250 pM TGFβ1 or TGFβ2 induces the loss of epithelial morphology (scoring as described in Compton et al. Dev Dyn, in press 2005) and membrane‐associated Zonula Occludens‐1 (ZO‐1). Inhibition of activin receptor‐like kinase (ALK) 5 by the addition of 2.5 μM SB431542 blocks the loss of epithelial character in response to either TGFβ1 or TGFβ2. Further, inhibition of p160Rho Kinase by 10 μg/ml Y27632 also blocks this effect. We have previously demonstrated that TGFβ1 or TGFβ2 induce similar alterations in chick epicardial cells that are accompanied by an increase in smooth muscle markers. These data describe the development of an in vitro system for the study of mouse epicardial cells. Using this system we demonstrate that, similar to chick epicardial explants, mouse epicardial explants lose epithelial character in response to TGFβ and that this effect requires ALK5 and p160 rho kinase. Source: HL67105 HL076133(AFA), & GM07347(LAC).