PT  - JOURNAL ARTICLE
AU  - Daiji Kiyozumi
AU  - Itsuko Nakano
AU  - Ryoko Sato-Nishiuchi
AU  - Satoshi Tanaka
AU  - Kiyotoshi Sekiguchi
TI  - Laminin is the ECM niche for trophoblast stem cells
AID  - 10.26508/lsa.201900515
DP  - 2020 Feb 01
TA  - Life Science Alliance
PG  - e201900515
VI  - 3
IP  - 2
4099  - https://www.life-science-alliance.org/content/3/2/e201900515.short
4100  - https://www.life-science-alliance.org/content/3/2/e201900515.full
SO  - Life Sci. Alliance2020 Feb 01; 3
AB  - The niche is a specialized microenvironment for tissue stem cells in vivo. It has long been emphasized that niche ECM molecules act on tissue stem cells to regulate their behavior, but the molecular entities of these interactions remain to be fully elucidated. Here, we report that laminin forms the in vivo ECM niche for trophoblast stem cells (TSCs), the tissue stem cells of the placenta. TSCs expressed fibronectin-binding, vitronectin-binding, and laminin-binding integrins, whereas the integrin ligands present in the TSC niche were collagen and laminin. Therefore, the only niche integrin ligand available for TSCs in vivo was laminin. Laminin promoted TSC adhesion and proliferation in vitro in an integrin binding–dependent manner. Importantly, when the integrin-binding ability of laminin was genetically ablated in mice, the size of the TSC population was significantly reduced compared with that in control mice. The present findings underscore an ECM niche function of laminin to support tissue stem cell maintenance in vivo.