title: Effective ex vivo expansion of hematopoietic stem cells using osteoblast-differentiated mesenchymal stem cells is CXCL12 dependent.
abstract: Effective ex vivo expansion of hematopoietic stem cells (HSCs) is a prerequisite for HSC transplantation. Growth and maintenance of HSC is dependent on cytokine and niche factors. We investigated whether mesenchymal stem cells (MSCs) or osteogenic cytokine-differentiated MSCs play a role in HSC expansion. We used the human HM3.B10 (B10) MSC cell line and the osteoblast-differentiated B10 (Ost-B10) as a feeder layer and examined ex vivo expansion of CD34(+)CD38(-) HSCs obtained from peripheral blood (PB) and cord blood (CB) with or without several growth cytokines. Both undifferentiated B10 and Ost-B10 cells exhibited similar effects on total HSC expansion; however, Ost-B10 demonstrated a higher potency in CD34(+)CD38(-) cell-specific proliferation in the presence of cytokines compared to undifferentiated B10 HSCs. Colony-forming cell assay and long-term culture initiating cell assay revealed that Ost-B10 displayed multipotent differentiation and enabled long-term ex vivo culture of HSCs. We next examined the relationship between HSC expansion and the presence of various chemokines. CXCL4 and CXCL12 expression were increased in Ost-B10 cells compared with the B10 cells. CD34(+)CD38(-) cells were significantly increased with CXCL12, but not CXCL4 treatment. siRNA inhibition of CXCL12 decreased CXCL12 secretion in both B10 and Ost-B10, whereas expansion of CD34(+)CD38(-) cells was decreased in Ost-B10 alone. These results demonstrated that ex vivo expansion of HSCs may be highly effective through osteoblast-differentiated MSCs acting as a feeder layer, and likely operates through the CXCL12 chemokines signaling pathway.
authors.affiliation: Central of Clinical Laboratory, Shimane University Hospital, Izumo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Mishima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagai
authors.forename: Sk
authors.initials: S
authors.lastname: Abdullah
authors.forename: Chikashi
authors.initials: C
authors.lastname: Matsuda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Taketani
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kumakura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibata
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ishikura
authors.forename: Seung U
authors.initials: SU
authors.lastname: Kim
authors.forename: Junichi
authors.initials: J
authors.lastname: Masuda
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology / Q000378:metabolism; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D039902:Multipotent Stem Cells / Q000166:cytology / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D010978:Platelet Factor 4 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D034741:RNA, Small Interfering; D010978:Platelet Factor 4