title: Low oxygen tension reveals distinct HOX codes in human cord blood-derived stromal cells associated with specific endochondral ossification capacities in vitro and in vivo.
abstract: Effects of oxygen tension on the generation, expansion, proliferation and differentiation of stromal cell types is widely described in the literature. However, data on the internal heterogeneity of applied cell populations at different O2levels and possible impacts on differentiation potentials are controversial. Here, the expression of 39 human HOX genes was determined in neonatal cord blood stromal cells and linked to differentiation-associated signatures. In cord blood, unrestricted somatic stromal cells (USSCs), lacking HOX gene expression, and cord blood-derived multipotent stromal cells (CB-MSCs), expressing about 20 HOX genes, are distinguished by their specific HOX code. Interestingly, 74% of the clones generated at 21% O2were HOX-negative USSCs, whereas 73% of upcoming clones at 3% O2were HOX-positive CB-MSCs. In order to better categorize distinct cell lines generated at 3% O2, the expression of all 39 HOX genes within HOX clusters A, B, C and D were tested and new subtypes defined: cells negative in all four HOX clusters (USSCs); cells positive in all four clusters (CB-MSCsABCD); and subpopulations missing a single cluster (CB-MSCsACDand CB-MSCsBCD). Comprehensive qPCR analyses of established chondro-osteomarkers revealed subtype-specific signatures verifiably associated with in vitro and in vivo differentiation capacity. The data presented here underline the necessity of better characterizing distinct cell populations at a clonal level, taking advantage of the inherent specific HOX code as a distinguishing feature between individual subtypes. Moreover, the correlation of subtype-specific molecular signatures with in vitro and in vivo bone formation is discussed. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Institute of Transplantation Diagnostics and Cell Therapeutics, Heinrich-Heine-University Medical Centre, Düsseldorf, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Liedtke
authors.affiliation: Stem Cell Laboratory, Department of Molecular Medicine, Sapienza University, Rome, Italy.
authors.forename: Benedetto
authors.initials: B
authors.lastname: Sacchetti
authors.affiliation: Research and Development, Medical Services, Finnish Red Cross Blood Service, Helsinki, Finland.
authors.forename: Anita
authors.initials: A
authors.lastname: Laitinen
authors.affiliation: Stem Cell Laboratory, Department of Molecular Medicine, Sapienza University, Rome, Italy.
authors.forename: Samantha
authors.initials: S
authors.lastname: Donsante
authors.affiliation: Institute of Transplantation Diagnostics and Cell Therapeutics, Heinrich-Heine-University Medical Centre, Düsseldorf, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Klöckers
authors.affiliation: Research and Development, Medical Services, Finnish Red Cross Blood Service, Helsinki, Finland.
authors.forename: Saara
authors.initials: S
authors.lastname: Laitinen
authors.affiliation: Stem Cell Laboratory, Department of Molecular Medicine, Sapienza University, Rome, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Riminucci
authors.affiliation: Institute of Transplantation Diagnostics and Cell Therapeutics, Heinrich-Heine-University Medical Centre, Düsseldorf, Germany.
authors.forename: Gesine
authors.initials: G
authors.lastname: Kogler
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D020219:Chondrogenesis / Q000187:drug effects / Q000235:genetics; D003001:Cloning, Molecular; D005312:Fetal Blood / Q000166:cytology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005801:Genes, Homeobox; D006801:Humans; D007231:Infant, Newborn; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics*; D010100:Oxygen / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D010100:Oxygen
keywords: BM-MSCs; CB-MSCs; HOX code; USSCs; chondrogenesis; endochondral signature; in vivo bone; osteogenesis