Fig. 1
From: Reconstructing the pulmonary niche with stem cells: a lung story
Directing lung stem cell differentiation in vitro via introduction of signaling ligands or small-molecule regulators mimicking in vivo lung development. a In mid-gastrula stage, DE elongates from the anterior end of primitive streak. The Nodalhigh region gives rise to the future foregut. b The AP axis along the gut tube is established at the end of gastrulation, regulated by the molecular gradient of ligands and antagonists of Wnt, Fgf4, and Bmp signaling. c The ventralization of foregut is regulated by the gradient of Wnt2/2b and Bmp, and its completion is marked by the emergence of Nkx2.1-positive lung progenitor cells. d The proximal–distal patterning and branching morphogenesis of developing lung is guided by a lateral inhibition mechanism of Fgf10. A/P, anterior/posterior. P/D, proximal/distal. D/V, dorsal/ventral