title: The role of the hyaluronan receptor CD44 in mesenchymal stem cell migration in the extracellular matrix.
abstract: In a previous investigation, we demonstrated that mesenchymal stem cells (MSCs) actively migrated to cardiac allografts and contributed to graft fibrosis and, to a lesser extent, to myocardial regeneration. The cellular/molecular mechanism responsible for MSC migration, however, is poorly understood. This paper examines the role of CD44-hyaluronan interaction in MSC migration, using a rat MSC line Ap8c3 and mouse CD44-/- or CD44+/+ bone marrow stromal cells (BMSCs). Platelet-derived growth factor (PDGF) stimulation of MSC Ap8c3 cells significantly increased the levels of cell surface CD44 detected by flow cytometry. The CD44 standard isoform was predominantly expressed by Ap8c3 cells, accounting for 90% of the CD44 mRNA determined by quantitative real-time polymerase chain reaction. Mouse CD44-/- BMSCs bonded inefficiently to hyaluronic acid (HA), whereas CD44+/+ BMSC and MSC Ap8c3 adhered strongly to HA. Adhesions of MSC Ap8c3 cells to HA were suppressed by anti-CD44 antibody and by CD44 small interfering RNA (siRNA). HA coating of the migration chamber significantly promoted passage of CD44+/+ BMSC or Ap8c3 cells, but not CD44-/- BMSCs, through the insert membranes (p < .01). Migration of MSC Ap8c3 was significantly inhibited by anti-CD44 antibodies (p < .01) and to a lesser extent by CD44 siRNA (p = .05). The data indicate that MSC Ap8c3 cells, in response to PDGF stimulation, express high levels of CD44 standard (CD44s) isoform, which facilitates cell migration through interaction with extracellular HA. Such a migratory mechanism could be critical for recruitment of MSCs into wound sites for the proposition of tissue regeneration, as well as for migration of fibroblast progenitors to allografts in the development of graft fibrosis.
authors.affiliation: Comprehensive Transplant Center, Department of Surgery, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, California 90048, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhu
authors.forename: Noboru
authors.initials: N
authors.lastname: Mitsuhashi
authors.forename: Andrew
authors.initials: A
authors.lastname: Klein
authors.forename: Lora W
authors.initials: LW
authors.lastname: Barsky
authors.forename: Kenneth
authors.initials: K
authors.lastname: Weinberg
authors.forename: Mark L
authors.initials: ML
authors.lastname: Barr
authors.forename: Achilles
authors.initials: A
authors.lastname: Demetriou
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Wu
mesh_terms: D000818:Animals; D001483:Base Sequence; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats
chemical_list: C476399:Cd44 protein, mouse; D018076:DNA, Complementary; D018960:Hyaluronan Receptors; D010982:Platelet-Derived Growth Factor; D034741:RNA, Small Interfering; D006820:Hyaluronic Acid