title: Hypoxia enhances the induction of human amniotic mesenchymal side population cells into vascular endothelial lineage.
abstract: Human amniotic mesenchymal side population (hAM-SP) cells have pluripotency and weak immunogenicity, and have promising roles in the field GAPDH of regenerative medicine. The aim of the present study was to determine whether hypoxic conditions induce the differentiation of hAM-SP cells into the vascular endothelial lineage. Mesenchymal cells were isolated from enzyme-treated amniotic membranes and stained with Hoechst 33342. The hAM-SP cells were negatively sorted by FACS and cultured in induction medium containing vascular endothelial growth factor (VEGF) under normoxic (20% O2) or hypoxic (1% O2) conditions for 1 or 2 weeks. The expression of endothelial markers such as kinase domain region (KDR), fms-like tyrosine kinase (Flt)-1, von Willebrand factor (vWF), vascular endothelial (VE)-cadherin and human vascular cell adhesion molecule (VCAM) at the gene and protein level was evaluated by real-time PCR and fluorescent immunostaining, respectively. The gene expression of KDR, Flt-1, VE-cadherin and vWF peaked after 2 weeks of culture. The protein expression of KDR and VE-cadherin was also enhanced after 2 weeks of culture under hypoxic conditions. To confirm the involvement of hypoxia-inducible factor (HIF) in the induction under hypoxic conditions, the expression of genes which are known to be upregulated by HIF was analyzed by DNA microarray. The expression of these genes increased under hypoxic conditions. hAM-SP cells cultured under hypoxic conditions differentiated into the vascular endothelial lineage, probably due to upregulation of the gene expression associated with angiogenesis through activation of the HIF system.
authors.affiliation: Graduate School of Medical Sciences, Kitasato University, Sagamihara, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Maruyama
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kokubo
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Shinbo
authors.forename: Minoru
authors.initials: M
authors.lastname: Hirose
authors.forename: Mamoru
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Norio
authors.initials: N
authors.lastname: Sakuragawa
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000650:Amnion / Q000166:cytology / Q000378:metabolism*; D015415:Biomarkers; D019070:Cell Lineage; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D058985:Side-Population Cells
chemical_list: D015415:Biomarkers; D051793:Hypoxia-Inducible Factor 1