Msx1 upregulates p27 expression to control cellular proliferation during valvuloseptal endocardial cushion formation in the chick embryonic heart.

In this study, we investigated the expression patterns of Msx1 mRNA and protein during chick heart development. Msx1 mRNA was localized in endothelial cells of the AV region at stage 14, and its protein was first detected at stage 15. Thereafter, Msx1 mRNA and protein were observed in the endothelial and mesenchymal cells of the OFT and AV regions. In vitro assays showed that ectopic Msx1 expression in endothelial cells induced p27, a cell-cycle inhibitor, expression and inhibited fibroblast growth factor 4 (FGF4)-induced cell proliferation. Although the FGF signal reduced the EMT-inducing activities of transforming growth factor β (TGFβ), ectopic Msx1 expression in endothelial cells enhanced TGFβ signaling-induced αSMA, an EMT marker, expression. These results suggest that Msx1 may support the transformation of endothelial cells due to a TGFβ signal in EMT during cushion tissue formation.
PMID: 33191650 [PubMed - as supplied by publisher]

Source: Anatomical Record - November 15, 2020 Category: Anatomy Authors: Yamagishi T, Narematsu M, Nakajima Y Tags: Anat Rec (Hoboken) Source Type: research