title: Expression of leukemia inhibitory factor and its receptors is increased during differentiation of human embryonic stem cells.
abstract: OBJECTIVE
  To investigate gene expression profiles during the early spontaneous differentiation of human embryonic stem cells (hESCs), with particular emphasis on leukemia inhibitory factor (LIF)-induced pathways and the ultrastructural surface morphology of the undifferentiated and spontaneously differentiated hESCs.
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  Four hESC cell lines.
  
  
  METHODS
  The effect of LIF on receptor expression level was studied in cultures.
  
  
  METHODS
  Gene expression in the hESC line HS237 was analyzed using microarrays. Real-time reverse-transcription polymerase chain reaction was used to validate the microarray results in four hESC lines (HS181, HS235, HS237, HS293). Immunohistochemistry was used to assay LIF, LIF receptor, and gp130 protein expression. Cell surface morphology was studied using scanning electron microscopy.
  
  
  RESULTS
  The expression of LIF, LIF receptor, and gp130 messenger RNA and protein was increased in spontaneously differentiated HS237 cells compared with undifferentiated cells, with high expression of an inhibitor of LIF-mediated signaling, suppressor of cytokine signaling-1, in undifferentiated hESCs. Genes, those expressed specifically and those shared in undifferentiated hESCs, differentiated cells, and in fibroblasts, were identified. Supplementation with LIF did not affect the LIF receptor expression.
  
  
  CONCLUSIONS
  The expression of LIF and its receptors is low in undifferentiated hESCs but increases during differentiation. Added LIF does not prevent spontaneous differentiation. Suppressor of cytokine signaling-1 may prevent LIF signaling in hESCs.
authors.affiliation: Department of Obstetrics and Gynecology, CLINTEC, Karolinska Institute, Karolinska University Hospital Huddinge, Stockholm, Sweden. lusine.aghajanova@klinvet.ki.se
authors.forename: Lusine
authors.initials: L
authors.lastname: Aghajanova
authors.forename: Heli
authors.initials: H
authors.lastname: Skottman
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Strömberg
authors.forename: José
authors.initials: J
authors.lastname: Inzunza
authors.forename: Riitta
authors.initials: R
authors.lastname: Lahesmaa
authors.forename: Outi
authors.initials: O
authors.lastname: Hovatta
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology*; D005347:Fibroblasts / Q000378:metabolism; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008855:Microscopy, Electron, Scanning; D012333:RNA, Messenger / Q000378:metabolism; D018121:Receptors, Cytokine / Q000235:genetics / Q000378:metabolism*; D053606:Receptors, OSM-LIF; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D015850:Interleukin-6; C507837:LIF protein, human; C507840:LIFR protein, human; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D012333:RNA, Messenger; D018121:Receptors, Cytokine; D053606:Receptors, OSM-LIF; C108944:SOCS1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; C480482:glycoprotein 130, human