title: Human bone marrow-derived mesenchymal stem cell gene expression patterns vary with culture conditions.
abstract: BACKGROUND
  Because of the heterogeneity of human mesenchymal stem cells (MSCs), methods for cell expansion in culture and the effects on gene expression are critical factors that need to be standardized for preparing MSCs. We investigated gene expression patterns of MSCs with different seeding densities and culture times.
  
  
  METHODS
  Bone marrow-derived MSCs were plated at densities from 200 cells/cm(2) to 5,000 cells/cm(2), and the gene expression patterns were evaluated over time using a reverse-transcription polymerase chain reaction assay.
  
  
  RESULTS
  The mRNA levels of factors that play a critical role in cell migration and tissue regeneration, such as podocalyxin-like protein (PODXL), α4-integrin, α6-integrin, and leukemia inhibitory factor (LIF), were higher in MSCs plated at 200 cells/cm(2) than in MSCs plated at 5,000 cells/cm(2). The mRNA levels of these factors gradually increased for 10 days and then decreased by day 15 in culture. MSCs seeded at 200 cells/cm(2) that were cultured for 10 days expressed high levels of Oct-4 and Nanog. Indoleamine 2,3-dioxygenase, cyclooxygenase-1, and hepatocyte growth factor expression were upregulated in the presence of the proinflammatory cytokine interferon-γ in these cells.
  
  
  CONCLUSIONS
  We found differences in the gene expression patterns of MSCs under different culture conditions. MSCs from 10-day cultures seeded at a low density were efficiently expanded, expressed PODXL, α6-integrin, α4-integrin, and LIF, and maintained properties like stemness and immunomodulation. Therefore, ex vivo expansion of MSCs maintained for an adequate culture time after plating at low cell density can provide an effective regenerative medicinal strategy for cell therapies using MSCs.
authors.affiliation: Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Myoung Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Dae Seong
authors.initials: DS
authors.lastname: Kim
authors.forename: Keon Hee
authors.initials: KH
authors.lastname: Yoo
authors.forename: Hye Ryung
authors.initials: HR
authors.lastname: Kim
authors.forename: In Keun
authors.initials: IK
authors.lastname: Jang
authors.forename: Ji Hyang
authors.initials: JH
authors.lastname: Lee
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Meong Hi
authors.initials: MH
authors.lastname: Son
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Hye Lim
authors.initials: HL
authors.lastname: Jung
authors.forename: Ki Woong
authors.initials: KW
authors.lastname: Sung
authors.forename: Hong Hoe
authors.initials: HH
authors.lastname: Koo
keywords: Cell therapy; Culture time; Gene expression pattern; Mesenchymal stem cell; Seeding density