title: Differentially circulating miRNAs after recent osteoporotic fractures can influence osteogenic differentiation.
abstract: Osteoporosis is the consequence of altered bone metabolism resulting in the systemic reduction of bone strength and increased risk of fragility fractures. MicroRNAs (miRNAs) regulate gene expression on a post-transcriptional level and are known to take part in the control of bone formation and bone resorption. In addition, it is known that miRNAs are secreted by many cell types and can transfer "messages" to recipient cells. Thus, circulating miRNAs might not only be useful as surrogate biomarkers for the diagnosis or prognosis of pathological conditions, but could be actively modulating tissue physiology. Therefore, the aim of this study was to test whether circulating miRNAs that exhibit changes in recent osteoporotic fracture patients could be causally related to bone metabolism. In the first step we performed an explorative analysis of 175 miRNAs in serum samples obtained from 7 female patients with recent osteoporotic fractures at the femoral neck, and 7 age-matched female controls. Unsupervised cluster analysis revealed a high discriminatory power of the top 10 circulating miRNAs for patients with recent osteoporotic fractures. In total 6 miRNAs, miR-10a-5p, miR-10b-5p, miR-133b, miR-22-3p, miR-328-3p, and let-7g-5p exhibited significantly different serum levels in response to fracture (adjusted p-value<0.05). These miRNAs were subsequently analyzed in a validation cohort of 23 patients (11 control, 12 fracture), which confirmed significant regulation for miR-22-3p, miR-328-3p, and let-7g-5p. A set of these and of other miRNAs known to change in the context of osteoporotic fractures were subsequently tested for their effects on osteogenic differentiation of human mesenchymal stem cells (MSCs) in vitro. The results show that 5 out of 7 tested miRNAs can modulate osteogenic differentiation of MSCs in vitro. Overall, these data suggest that levels of specific circulating miRNAs change in the context of recent osteoporotic fractures and that such perturbations of "normal" levels might affect bone metabolism or bone healing processes.
authors.affiliation: CD Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Weilner
authors.affiliation: TAmiRNA GmbH, 1190 Vienna, Austria.
authors.forename: Susanna
authors.initials: S
authors.lastname: Skalicky
authors.affiliation: CD Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Salzer
authors.affiliation: CD Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Keider
authors.affiliation: TAmiRNA GmbH, 1190 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Red Cross Blood Transfusion Service of Upper Austria, Austrian Cluster for Tissue Regeneration, 4020 Linz, Austria.
authors.forename: Florian
authors.initials: F
authors.lastname: Hildner
authors.affiliation: Red Cross Blood Transfusion Service of Upper Austria, Austrian Cluster for Tissue Regeneration, 4020 Linz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Gabriel
authors.affiliation: Salzkammergut-Klinikum Gmunden, 4810 Gmunden, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Dovjak
authors.affiliation: Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University Vienna, 1090 Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Pietschmann
authors.affiliation: Evercyte GmbH, 1190 Vienna, Austria.
authors.forename: Regina
authors.initials: R
authors.lastname: Grillari-Voglauer
authors.affiliation: CD Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria; TAmiRNA GmbH, 1190 Vienna, Austria; Evercyte GmbH, 1190 Vienna, Austria. Electronic address: johannes.grillari@boku.ac.at.
authors.forename: Johannes
authors.initials: J
authors.lastname: Grillari
authors.affiliation: CD Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, 1190 Vienna, Austria; TAmiRNA GmbH, 1190 Vienna, Austria. Electronic address: matthias.hackl@tamirna.com.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hackl
mesh_terms: D000368:Aged; D002454:Cell Differentiation / Q000235:genetics*; D005260:Female; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D035683:MicroRNAs / Q000097:blood*; D010012:Osteogenesis / Q000235:genetics*; D015663:Osteoporosis, Postmenopausal / Q000150:complications; D058866:Osteoporotic Fractures / Q000097:blood / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014162:Transfection
chemical_list: D035683:MicroRNAs
keywords: Bone; Circulating microRNA (miRNA); Mesenchymal stem cells; Osteogenic differentiation; Osteoporosis; Quantitative PCR (qPCR)