title: MiRNA profiling of whole trabecular bone: identification of osteoporosis-related changes in MiRNAs in human hip bones.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are important regulators of gene expression, with documented roles in bone metabolism and osteoporosis, suggesting potential therapeutic targets. Our aim was to identify miRNAs differentially expressed in fractured vs nonfractured bones. Additionally, we performed a miRNA profiling of primary osteoblasts to assess the origin of these differentially expressed miRNAs.
  
  
  METHODS
  Total RNA was extracted from (a) fresh femoral neck trabecular bone from women undergoing hip replacement due to either osteoporotic fracture (OP group, n = 6) or osteoarthritis in the absence of osteoporosis (Control group, n = 6), matching the two groups by age and body mass index, and (b) primary osteoblasts obtained from knee replacement due to osteoarthritis (n = 4). Samples were hybridized to a microRNA array containing more than 1900 miRNAs. Principal component analysis (PCA) plots and heat map hierarchical clustering were performed. For comparison of expression levels, the threshold was set at log fold change > 1.5 and a p-value < 0.05 (corrected for multiple testing).
  
  
  RESULTS
  Both PCA and heat map analyses showed that the samples clustered according to the presence or absence of fracture. Overall, 790 and 315 different miRNAs were detected in fresh bone samples and in primary osteoblasts, respectively, 293 of which were common to both groups. A subset of 82 miRNAs was differentially expressed (p < 0.05) between osteoporotic and control osteoarthritic samples. The eight miRNAs with the lowest p-values (and for which a validated miRNA qPCR assay was available) were assayed, and two were confirmed: miR-320a and miR-483-5p. Both were over-expressed in the osteoporotic samples and expressed in primary osteoblasts. miR-320a is known to target CTNNB1 and predicted to regulate RUNX2 and LEPR, while miR-483-5p down-regulates IGF2. We observed a reduction trend for this target gene in the osteoporotic bone.
  
  
  CONCLUSIONS
  We identified two osteoblast miRNAs over-expressed in osteoporotic fractures, which opens novel prospects for research and therapy.
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: De-Ugarte
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.
authors.forename: Guy
authors.initials: G
authors.lastname: Yoskovitz
authors.affiliation: Departament de Genètica, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Universitat de Barcelona, IBUB, Barcelona, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Balcells
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.|Internal Medicine Department, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Robert
authors.initials: R
authors.lastname: Güerri-Fernández
authors.affiliation: Orthopaedic Surgery and Traumatology Department, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Santos
authors.initials: S
authors.lastname: Martinez-Diaz
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.|Internal Medicine Department, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mellibovsky
authors.affiliation: Departament de Genètica, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Universitat de Barcelona, IBUB, Barcelona, Spain.
authors.forename: Roser
authors.initials: R
authors.lastname: Urreizti
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.|Internal Medicine Department, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Nogués
authors.affiliation: Departament de Genètica, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Universitat de Barcelona, IBUB, Barcelona, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Grinberg
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain. ngarcia@imim.es.
authors.forename: Natalia
authors.initials: N
authors.lastname: García-Giralt
authors.affiliation: Musculoskeletal research group, IMIM (Hospital del Mar Medical Research Institute), Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), ISCIII, Barcelona, Spain.|Internal Medicine Department, Hospital del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Díez-Pérez
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000378:metabolism; D010024:Osteoporosis / Q000235:genetics* / Q000473:pathology; D010384:Pelvic Bones / Q000378:metabolism* / Q000473:pathology
chemical_list: C035170:IGF2 protein, human; D035683:MicroRNAs; D007335:Insulin-Like Growth Factor II