title: Enhanced generation of hematopoietic cells from human hepatocarcinoma cell-stimulated human embryonic and induced pluripotent stem cells.
abstract: OBJECTIVE
  Human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) constitute unique sources of pluripotent cells, although the molecular mechanisms involved in their differentiation into specific lineages are just beginning to be defined. Here we evaluated the ability of MEDII (medium conditioned by HepG2 cells, a human hepatocarcinoma cell line) to selectively enhance generation of mesodermal derivatives, including hematopoietic cells, from hESCs and hiPSCs.
  
  
  METHODS
  Test cells were exposed to MEDII prior to being placed in conditions that promote embryoid body (EB) formation. Hematopoietic activity was measured by clonogenic assays, flow cytometry, quantitative real-time polymerase chain reaction of specific transcript complementary DNAs and the ability of cells to repopulate sublethally irradiated nonobese diabetic/severe combined immunodeficient interleukin-2 receptor gamma-chain-null mice for almost 1 year.
  
  
  RESULTS
  Exposure of both hESCs and hiPSCs to MEDII induced a rapid and preferential differentiation of hESCs into mesodermal elements. Subsequently produced EBs showed a further enhanced expression of transcripts characteristic of multiple mesodermal lineages, and a concurrent decrease in endodermal and ectodermal cell transcripts. Frequency of all types of clonogenic hematopoietic progenitors in subsequently derived EBs was also increased. In vivo assays of MEDII-treated hESC-derived EBs also showed they contained cells able to undertake low-level but longterm multilineage repopulation of primary and secondary nonobese diabetic/severe combined immunodeficient interleukin-2 receptor gamma-chain-null mice.
  
  
  CONCLUSIONS
  MEDII treatment of hESCs and hiPSCs alike selectively enhances their differentiation into mesodermal cells and allows subsequent generation of detectable levels of hematopoietic progenitors with in vitro and in vivo differentiating activity.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, BC, Canada.
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Kardel
authors.forename: Michael D
authors.initials: MD
authors.lastname: O'Connor
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Eaves
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D019070:Cell Lineage; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D053595:Embryonic Stem Cells / Q000166:cytology*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D051379:Mice; D019899:Paracrine Communication; D039904:Pluripotent Stem Cells / Q000166:cytology*
chemical_list: D017077:Culture Media, Conditioned