title: MiR-7b directly targets DC-STAMP causing suppression of NFATc1 and c-Fos signaling during osteoclast fusion and differentiation.
abstract: DC-STAMP is a key regulating molecule of osteoclastogenesis and osteoclast precursor (OCP) fusion. Emerging lines of evidence showed that microRNAs play crucial roles in bone metabolism and osteoclast differentiation, but no microRNA has yet been reported to be directly related to OCPs fusion. Through a microarray, we found that the expression of miR-7b in RAW264.7 cells was significantly decreased after induction with M-CSF and RANKL. The overexpression of miR-7b in RAW264.7 cells attenuated the number of TRAP-positive cells number and the formation of multinucleated cells, whereas the inhibition of miR-7b enhanced osteoclastogenesis. Through a dual luciferase reporter assay, we confirmed that miR-7b directly targets DC-STAMP. Other fusogenic molecules, such as CD47, ATP6v0d2, and OC-STAMP, were detected to be down-regulated in accordance with the inhibition of DC-STAMP. Because DC-STAMP also participates in osteoclast differentiation through the ITAM-ITIM network, multiple osteoclast-specific genes in the ITAM-ITIM network were detected to identify how DC-STAMP is involved in this process. The results showed that molecules associated with the ITAM-ITIM network, such as NFATc1 and OSCAR, which are crucial in osteoclastogenesis, were consistently altered due to DC-STAMP inhibition. These findings suggest that miR-7b inhibits osteoclastogenesis and cell-cell fusion by directly targeting DC-STAMP. In addition, the inhibition of DC-STAMP and its downstream signals changed the expression of other fusogenic genes and key regulating genes, such as Nfatc1, c-fos, Akt, Irf8, Mapk1, and Traf6. In conclusion, our findings indicate that miR-7b may be a potential therapeutic target for the treatment of osteoclast-related bone disorders.
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China; National & Regional United Engineering Laboratory of Tissue Engineering, Department of Orthopedics, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Ce
authors.initials: C
authors.lastname: Dou
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Kang
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Xiaochao
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China.
authors.forename: Junyu
authors.initials: J
authors.lastname: Xiang
authors.affiliation: National & Regional United Engineering Laboratory of Tissue Engineering, Department of Orthopedics, Southwest Hospital, Third Military Medical University, Chongqing, China. Electronic address: xujianzhong1962@163.com.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University, Chongqing, China. Electronic address: dongshiwu@tmmu.edu.cn.
authors.forename: Shiwu
authors.initials: S
authors.lastname: Dong
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D002459:Cell Fusion; D002478:Cells, Cultured; D015536:Down-Regulation / Q000235:genetics; D016762:Genes, fos / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000502:physiology*; D050778:NFATC Transcription Factors / Q000235:genetics* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010010:Osteoclasts / Q000502:physiology*; D034622:RNA Interference / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics
chemical_list: C499636:DC-STAMP protein, mouse; C549243:MIRN7 microRNA, mouse; D008565:Membrane Proteins; D035683:MicroRNAs; D050778:NFATC Transcription Factors; D009419:Nerve Tissue Proteins; C494005:Nfatc1 protein, mouse
keywords: Cell fusion; DC-STAMP; Osteoclastogenesis; microRNA