title: Time-course transcriptional profiling of human amniotic fluid-derived stem cells using microarray.
abstract: OBJECTIVE
  To maintain the homeostasis of stem cells and prevent their ability to initiate tumorigenesis, it is important to identify and modify factors that prevent or accelerate stem cell senescence. We used microarrays to attempt to identify such factors in human amniotic fluid (HAF)-derived stem cells.
  
  
  METHODS
  To identify gene expression changes over a time course, we compared gene expression profiles of HAF-derived stem cells in different passages (1(st), 2(nd), 4(th), 6(th), 8(th), and 10(th)) using a Sentrix Human illumina microarray.
  
  
  RESULTS
  Of the 25,804 genes in the microarray chip, 1,970 showed an over 2-fold change relative to the control (the 1(st) passage)-either upregulated or downregulated. Quantitative real-time PCR validated the microarray data for selected genes: markedly increased genes were CXCL12, cadherin 6 (CDH6), and folate receptor 3 (FOLR3). Downregulated genes included cyclin D2, keratin 8, insulin-like growth factor 2 (IGF2), natriuretic peptide precursor B (NPPB) and cellular retinoic acid binding protein 2 (CRABP2). The expression pattern of the selected genes was consistent with the microarray data except for CXCL12 and IGF2. Interestingly, the expression of NPPB was dramatically downregulated along the time course; it was almost completely shut-down by the 10(th) passage. In contrast, FOLR3 mRNA expression was dramatically increased.
  
  
  CONCLUSIONS
  Taken together, although a function for NPPB and FOLR3 in stem cell senescence has not been reported, our results strongly suggest that NPPB and/or FOLR3 play a significant role in the regulation of stem cell senescence.
authors.affiliation: Department of Obstetrics and Gynecology, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Yong Wook
authors.initials: YW
authors.lastname: Kim
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Su-Mi
authors.initials: SM
authors.lastname: Bae
authors.forename: Young Jae
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jong-Chul
authors.initials: JC
authors.lastname: Shin
authors.forename: Heung-Jae
authors.initials: HJ
authors.lastname: Chun
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Rhie
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Kim
authors.forename: Haekwon
authors.initials: H
authors.lastname: Kim
authors.forename: Woong Shick
authors.initials: WS
authors.lastname: Ahn