title: miR-23b targets Smad 3 and ameliorates the LPS-inhibited osteogenic differentiation in preosteoblast MC3T3-E1 cells.
abstract: Lipopolysaccharide (LPS) has been confirmed to be the main inhibitor in osteogenic differentiation, posing a clinical challenge to bone healing, particularly for trauma followed by endotoxinemia/sepsis. However, the molecular mechanism remains ambiguous. miR-23b, which regulates multiple signaling pathways in inflammation, has been shown to be deregulated by LPS. In this study, we examined the LPS-mediated regulation on the expression of miR-23b and Smad 3 in preosteoblast MC3T3-E1 cells. Then we determined the regulation of miR-23b overexpression on the Smad 3 expression and on the LPS-mediated inhibition of bone morphogenetic protein-2 (BMP-2)-induced osteogenic differentiation. Our results demonstrated that LPS significantly downregulated the expression of miR-23b, while upregulating Smad 3 in MC3T3-E1 cells. However, the transfection with miR-23b mimics markedly downregulated the Smad 3 in both mRNA and protein levels, via the specific binding to the 3'-untranslated region (UTR) of Smad 3. Moreover, though LPS markedly downregulated the BMP-2-induced osteogenic differentiation of MC3T3-E1 cells by inhibiting the expression of alkaline phosphatase (ALP), Osteocalcin (OCN), Osteopontin (OPN) and Runt-related transcription factor 2 (RUNX2). The upregulated miR-23b reversed such downregulation of ALP, OCN, OPN and RUNX2 in the MC3T3-E1 cells which were treated both with LPS and BMP-2. In conclusion, our data indicates that miR-23b ameliorates the LPS-mediated inhibition of BMP-2-induced osteogenic differentiation in MC3T3-E1 cells, implying the protective role of miR-23b in the LPS-mediated inhibition of osteogenic differentiation and bone formation.
authors.affiliation: Department of Orthopedic Trauma, Yantai Yuhuangding Hospital of Qingdao University, China.
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Hao
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Su
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics*; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D003864:Depression, Chemical; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology*; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics*; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D051900:Smad3 Protein / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D050659:Core Binding Factor Alpha 1 Subunit; D008070:Lipopolysaccharides; D035683:MicroRNAs; C534062:Mirn23b microRNA, mouse; C493716:Runx2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D015675:Osteocalcin; D053495:Osteopontin; D000469:Alkaline Phosphatase