title: Isolation and characterization of CD146+ multipotent mesenchymal stromal cells.
abstract: Mesenchymal stromal cells (MSCs) represent a bone marrow (BM) population, classically defined by five functional properties: extensive proliferation, ability to differentiate into osteoblasts, chondrocytes, adipocytes, and stromal cells-supporting hematopoiesis. However, research progress in this area has been hampered by lack of suitable markers and standardized procedures for MSC isolation. We have isolated a CD146(+) multipotent MSC population from 20 human BM donors displaying the phenotype of self-renewing osteoprogenitors; an extensive 12-week proliferation; and the ability to differentiate in osteoblasts, chondrocytes, adipocytes, and stromal cells supporting hematopoiesis. Furthermore, the CD146(+) MSCs secrete a complex combination of growth factors (GFs) controlling hematopoietic stem cells (HSCs) function, while providing a >2-log increase in the long-term culture (LTC) colony output in 8-week LTC over conventional assays. The hematopoietic stromal function exhibited by the MSCs was further characterized by manipulating LTCs with the chemical inhibitors Imatinib or SU-5416, targeting two GF receptors (GFRs), KIT or VEGFR2/1, respectively. Both treatments similarly impaired LTC colony output, indicating key roles for these two GF/GFR interactions to support LTC-initiating cell activity. CD146(+) MSCs may thus represent a tool to explore the MSC-HSC cross-talk in an in vitro surrogate model for HSC "niches," and for regenerative therapy studies. In addition, the MSC microRNA (miRNA) expression profile was analyzed by microarrays in both basic conditions and chondrogenic differentiation. Our analysis revealed that several miRNAs are modulated during chondrogenesis, and many of their putative targets are genes involved in chondrogenic differentiation.
authors.affiliation: Department of Hematology, Oncology, and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sorrentino
authors.forename: Manuela
authors.initials: M
authors.lastname: Ferracin
authors.forename: Germana
authors.initials: G
authors.lastname: Castelli
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffoni
authors.forename: Giada
authors.initials: G
authors.lastname: Tomaselli
authors.forename: Marta
authors.initials: M
authors.lastname: Baiocchi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Fatica
authors.forename: Massimo
authors.initials: M
authors.lastname: Negrini
authors.forename: Cesare
authors.initials: C
authors.lastname: Peschle
authors.forename: Mauro
authors.initials: M
authors.lastname: Valtieri
mesh_terms: D015153:Blotting, Western; D051929:CD146 Antigen / Q000096:biosynthesis*; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D002469:Cell Separation / Q000379:methods; D019902:Chondrocytes / Q000166:cytology; D020869:Gene Expression Profiling; D006801:Humans; D016130:Immunophenotyping; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors
chemical_list: D051929:CD146 Antigen; D036341:Intercellular Signaling Peptides and Proteins; D035683:MicroRNAs