Canonical and non-canonical Wnts differentially affect the development potential of primary isolate of human bone marrow mesenchymal stem cells.
This study examines the role of Wnt signaling events in regulating the differential potential of mesenchymal stem cells (MSCs) from adult bone marrow (BM). Immunohistochemical analysis of BM revealed co-localization of Wnt5a protein, a non-canonical Wnt, with CD45(+) cells and CD45(-) STRO-1(+) cells, while Wnt3a expression, a canonical Wnt, was associated with the underlying stroma matrix, suggesting that Wnts may regulate MSCs in their niche in BM. To elucidate the role of Wnts in MSC development, adult human BM-derived mononuclear cells were maintained as suspension cultures to recapitulate the marrow cellular environment, in serum-free, with the addition of Wnt3a and Wnt5a protein. Results showed that Wnt3a increased cell numbers and expanded the pool of MSCs capable of colony forming unit -- fibroblast (CFU-F) and CFU -- osteoblast (O), while Wnt5a maintained cell numbers and CFU-F and CFU-O numbers. However, when cells were cultured directly onto tissue culture plastic, Wnt5a increased the number of CFU-O relative to control conditions. These findings suggest the potential dual role of Wnt5a in the maintenance of MSCs in BM and enhancing osteogenesis ex vivo. Our work provides evidence that Wnts can function as mesenchymal regulatory factors by providing instructive cues for the recruitment, maintenance, and differentiation of MSCs.
Baksh
Dolores
D
Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, National Institutes of Health, Department and Health and Human Services, Bethesda, MD 20892, USA.
Tuan
Rocky S
RS
D053687:Adult Stem Cells / Q000276:immunology / Q000378:metabolism*; D000368:Aged; D019898:Autocrine Communication; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D017077:Culture Media, Conditioned / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D017493:Leukocyte Common Antigens / Q000032:analysis; D059630:Mesenchymal Stem Cells / Q000276:immunology / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D010006:Osteoblasts / Q000378:metabolism; D019899:Paracrine Communication; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D000071818:Wnt-5a Protein; D060508:Wnt3 Protein; D060509:Wnt3A Protein
D017077:Culture Media, Conditioned; D011518:Proto-Oncogene Proteins; C555510:WNT3A protein, human; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human