title: Cyclic strain induces mouse embryonic stem cell differentiation into vascular smooth muscle cells by activating PDGF receptor beta.
abstract: Embryonic stem (ES) cells are exposed to fluid-mechanical forces, such as cyclic strain and shear stress, during the process of embryonic development but much remains to be elucidated concerning the role of fluid-mechanical forces in ES cell differentiation. Here, we show that cyclic strain induces vascular smooth muscle cell (VSMC) differentiation in murine ES cells. Flk-1-positive (Flk-1+) ES cells seeded on flexible silicone membranes were subjected to controlled levels of cyclic strain and examined for changes in cell proliferation and expression of various cell lineage markers. When exposed to cyclic strain (4-12% strain, 1 Hz, 24 h), the Flk-1+ ES cells significantly increased in cell number and became oriented perpendicular to the direction of strain. There were dose-dependent increases in the VSMC markers smooth muscle alpha-actin and smooth muscle-myosin heavy chain at both the protein and gene expression level in response to cyclic strain, whereas expression of the vascular endothelial cell marker Flk-1 decreased, and there were no changes in the other endothelial cell markers (Flt-1, VE-cadherin, and platelet endothelial cell adhesion molecule 1), the blood cell marker CD3, or the epithelial marker keratin. The PDGF receptor beta (PDGFR beta) kinase inhibitor AG-1296 completely blocked the cyclic strain-induced increase in cell number and VSMC marker expression. Cyclic strain immediately caused phosphorylation of PDGFR beta in a dose-dependent manner, but neutralizing antibody against PDGF-BB did not block the PDGFR beta phosphorylation. These results suggest that cyclic strain activates PDGFR beta in a ligand-independent manner and that the activation plays a critical role in VSMC differentiation from Flk-1+ ES cells.
authors.affiliation: Dept. of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Shimizu
authors.forename: Kimiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Syotaro
authors.initials: S
authors.lastname: Obi
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kumagaya
authors.forename: Tomomi
authors.initials: T
authors.lastname: Masumura
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Shimano
authors.forename: Keiji
authors.initials: K
authors.lastname: Naruse
authors.forename: Jun K
authors.initials: JK
authors.lastname: Yamashita
authors.forename: Takashi
authors.initials: T
authors.lastname: Igarashi
authors.forename: Joji
authors.initials: J
authors.lastname: Ando
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D000077214:Becaplermin; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D019070:Cell Lineage; D049109:Cell Proliferation; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D013314:Stress, Mechanical; D020032:Tyrphostins / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D000199:Actins; D000906:Antibodies; D010982:Platelet-Derived Growth Factor; D047428:Protein Kinase Inhibitors; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D020032:Tyrphostins; C106250:6,7-dimethoxy-3-phenylquinoxaline; D000077214:Becaplermin; D020797:Receptor, Platelet-Derived Growth Factor beta; D040301:Vascular Endothelial Growth Factor Receptor-2; D018995:Myosin Heavy Chains