In vitro modeling of paraxial and lateral mesoderm differentiation reveals early reversibility

¹ Science of In-Home Medicine, Health and Community Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8560, Japan; Laboratory for Stem Cell Biology, RIKEN Center for Development Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
² Laboratory for Stem Cell Biology, RIKEN Center for Development Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
³ Laboratory for Stem Cell Biology, RIKEN Center for Development Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan; Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, Japan Science and Technology Corporation, Discovery Research Laboratory, Tanabe Seiyaku Co., Ltd., 3-16-89 Kashima, Yodogawa-ku, Osaka 532-8505 Japan
⁴ Science of In-Home Medicine, Health and Community Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8560, Japan

^* To whom correspondence should be addressed. E-mail: tera{at}cdb.riken.jp.

	Abstract

Endothelial cells (ECs) are thought to be derived mainly from the VEGFR2 positive lateral mesoderm during early embryogenesis. In this study, we specified several pathways for EC differentiation using a murine embryonic stem (ES) cell differentiation culture system that is a model for cellular process during early embryogenesis. Based on the results of in vitro fate analysis, we show that, in the main pathway, committed ECs are differentiated through VEGFR2⁺PDGFR^- single positive population (VSP) that is derived from VEGFR2⁺PDGFR⁺ double positive population (DP). This major differentiation course was also assured by the DNA microarray gene analysis. In addition to this main pathway, however, ECs also can be generated from VEGFR2^-PDGFR⁺ single positive populations (PSP) which represent paraxial mesodermal lineage and is also derived from DP. Our results strongly suggest that even after differentiation from common progenitor DP into VSP and PSP, the two populations continue spontaneous switch of the surface phenotype, which results in switch of their eventual fates. The rate of this inter-lineage conversion between VSP and PSP is unexpectedly high. Because of this potential to undergo fate switch, we conclude that ECs can be generated via multiple pathways in in vitro ES cell differentiation.