SAT0030 Visfatin down-regulates growth promoting lncrna h19 in osteogenic differentiation of mesenchymal stromal cells
Authors: D.M. Küppers, L. Tsiklauri, M.-L. Hülser, K. Frommer, S. Rehart, U. Müller-Ladner, E. Neumann
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Destructive bone diseases like osteoarthritis and osteoporosis are causes of chronic pain and disability. Mesenchymal stromal cells (MSC) are key regulators for bone homeostasis due to their potential for osteogenic differentiation, preventing bone loss and promoting tissue repair. Pro-inflammatory factors including adipokines such as visfatin alter the osteogenic potential of MSCs and may contribute to the shift towards adipogenic differentiation observed in osteoporosis. Long non-coding RNA H19 is one of the first lncRNAs discovered and best understood e.g. in embryonic growth and tumour formation. lncRNAs interact directly with DNA, RNA as well as proteins and fill a regulatory gap between the ribonucleic and protein world. H19 upregulation was shown in osteogenic differentiation of MSCs<sup>1</sup>. H19 increases the osteogenic potential by acting as a sponge for miRNA 675, 141 and 22, influencing TGFβ1 and Wnt/β-catenin pathways<sup>2,3</sup>. H19 may hence be involved in MSC mediated bone homeostasis. <h3>Objectives</h3> To analyse the link between adipokines and bone remodelling in destructive bone disease. To investigate the influence of adipokines on MSCs and on the expression of lncRNA H19 during osteogenesis. <h3>Methods</h3> Commercial human MSCs (hMSC) and primary human MSCs (phMSC) from osteoarthritis patients after knee replacement surgery were treated with differentiation medium to induce osteogenic differentiation (OD). Matrix mineralization was quantified after 21 days of OD by Alizarin Red. Expression of H19 and IL-6 protein production were measured using realtime PCR and ELISA at day 2/7/14 of OD. <h3>Results</h3> H19 up-regulation in MSCs during OD could be confirmed in a time dependent manner. Visfatin-stimulation of MSC during OD increased matrix mineralization over time as well as IL-6 production (day 7, 14, 21: 46-, 93-, 78-fold). Visfatin stimulation down-regulated H19 expression up to 10-fold over the course of OD compared to non-stimulated control. The effect was significant in phMSCs in 2/3 measured time points (day 7, p=0.03; day 14, p=0.002, n=3) and in hMSCs on day 14 (p=0.0003, n=4). <h3>Conclusions</h3> During osteogenic differentiation of MSCs, visfatin showed pro-inflammatory and mineralization promoting effects. However, H19 was significantly down-regulated by visfatin during osteogenic differentiation. This may contribute to the loss of osteogenic potency of MSCs in inflamed tissues with increased visfatin concentration as observed in affected areas of destructive bone disease. Further research to understand the H19 effector mechanisms on osteogenic differentiation and osteogenic potency of MSCs are in progress. <h3>References</h3> [1] Wang L. Differential expression of long noncoding ribonucleic acids during osteogenic differentiation of human bone marrow mesenchymal stem cells. Int. Orthop2015;39:1013–1019. [2] Huang Y. Long Noncoding RNA H19 Promotes Osteoblast Differentiation Via TGF-?1/Smad3/HDAC Signaling Pathway by Deriving miR-675. Stem Cells2015;33:3481–3492. [3] Liang W-C. H19 activates Wnt signaling and promotes osteoblast differentiation by functioning as a competing endogenous RNA. Sci. Rep2016;6;20121. <h3>Disclosure of Interest</h3> None declared