title: Hyaluronan is required for generation of hematopoietic cells during differentiation of human embryonic stem cells.
abstract: Hyaluronan (HA) is an important component of the microenvironment in bone marrow, but its role in regulation of the development of hematopoietic cells is not well understood. To address the role of HA in regulation of human embryonic stem cell (hESC) differentiation into the hematopoietic lineage, we screened for genes encoding components of the HA pathway. Using gene arrays, we found that HA synthases and HA receptors are expressed in both undifferentiated and differentiating hESCs. Enzymatic degradation of HA resulted in decreased numbers of hematopoietic progenitors and lower numbers of CD45+ cells generated in HA-deprived embryoid bodies (EBs). In addition, deprivation of HA resulted in the inhibition of generation of CD31+ cells, stromal fibroblast-like cells and contracting myocytes in EBs. RT-PCR and immunocytochemistry revealed that HA deprivation did not influence the dynamics of OCT4 expression, but decreased the expression of BRY, an early mesoderm marker, and BMP2, a later mesoderm marker in differentiating EBs. In addition, the endoderm markers α-FP and SOX17 were decreased, whereas the expression of the ectoderm markers GFAP and FGF5 was higher in HA-deprived cultures. Our findings indicate that endogenously produced HA contributes to the network that regulates the differentiation of hESC and the generation of mesodermal lineage in general and hematopoietic cells specifically.
authors.affiliation: Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA.
authors.forename: Ingrid U
authors.initials: IU
authors.lastname: Schraufstatter
authors.forename: Naira
authors.initials: N
authors.lastname: Serobyan
authors.forename: Jeanne
authors.initials: J
authors.lastname: Loring
authors.forename: Sophia K
authors.initials: SK
authors.lastname: Khaldoyanidi
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D019070:Cell Lineage; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006413:Hematopoietic System / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006820:Hyaluronic Acid / Q000502:physiology*; D007124:Immunoenzyme Techniques; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D006820:Hyaluronic Acid