Carter, Edward, Miron-Buchacra, G., Goldoni, Silvia, Danahay, Henry, Westwick , John, Watson, M.L., Tosh, David and Ward, Stephen (2014) Phosphoinositide 3-kinase alpha-dependent regulation of branching morphogenesis in murine embryonic lung: evidence for a role in determining morphogenic properties of FGF7. PLOS ONE.

Abstract

While the molecular mechanisms controlling early lung development are well
established, the signalling pathways involved in branching morphogenesis
have yet to be fully elucidated. Herein we dissected the role of the
phosphoinositide-3-kinase (PI3K) pathway in the lung branching program
using two ex vivo models of murine lung development. We initially addressed
whether the pan class I PI3K inhibitor ZSTK474 altered branching in a whole
lung explant model. Addition of ZSTK474 enhanced branching as measured
by an increase in the number of terminal branches over 24 and 48 hours of
culture relative to controls. Enhanced branching was also observed when the
explants were cultured with an inhibitor of Akt (Akt inhibitor VIII) and mTORC2
(AZD8055) but not with an inhibitor of mTORC1 (rapamycin). In order to
determine the isoform dependence of the PI3K phenomenon, we tested two
alpha isoform (BYL719 and A66) and two beta isoform (GSK2636771 and
TGX-221) inhibitors. We found that the alpha, but not beta, inhibitors
enhanced branching. This result suggests the alpha isoform of PI3K is a key
driver in branching morphogenesis. As the whole lung explant model contains
both epithelium and mesenchymal tissue we sought to identify if the effect of
PI3K inhibition on branching morphogenesis is specific to the epithelium or
secondary to an effect on the mesenchyme. Isolated lung epithelium cultured
with FGF7 formed large cyst-like structures, whereas co-culture with FGF7
and ZSTK474 induced the formation of defined branches from the initial
isolate. This would imply that inhibition of PI3K is sufficient to alter the
morphogenic properties of FGF7. Together these data suggest a novel role
for PI3K in the branching program of the murine embryonic lung potentially by
affecting the signalling of FGF7.

Item Type:	Article
Date Deposited:	13 Oct 2015 13:13
Last Modified:	13 Oct 2015 13:13
URI:	https://oak.novartis.com/id/eprint/20780