Knockdown of HDAC9 Inhibits Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells Partially by Suppressing the MAPK Signaling Pathway

Abstract

Bo Wang,1,* Song Gong,2,* Lizhi Han,2 Wenkai Shao,2 Zilin Li,2 Jiawei Xu,2 Xiao Lv,2 Baojun Xiao,2 Yong Feng2 1Department of Rehabilitation, Wuhan No.1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, People’s Republic of China; 2Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, People’s Republic of China*These authors contributed equally to this workCorrespondence: Baojun Xiao; Yong Feng, Email [email protected]; [email protected]: Histone deacetylase 9 (HDAC9) is a member of the HDAC gene family that plays essential roles in the organization of transcriptional regulation by catalyzing deacetylation of histone proteins. However, the effects of HDAC9 on osteonecrosis of femoral head (ONFH) have not been investigated. The present study aimed to reveal whether histone deacetylase 9 (HDAC9) regulated osteogenic differentiation.Methods: A lentiviral knockdown HDAC9 model was established in hBMSCs. Osteoblast-specific gene expression, such as Runx2, OCN was examined by qRT-PCR and Western blot, respectively. Though transcriptome sequencing and enrichment analysis, related signal pathways caused by down-regulation of HDAC9 were screened. The effect of HDAC9 on MAPK signaling pathway was determined by Western blot. Eventually, tert-Butylhydroquinone (tBHQ) was used to examine the effect of MAPK activation on osteogenesis in HDAC9 knockdown hBMSCs.Results: A lentiviral knockdown HDAC9 model was successfully established in hBMSCs. HDAC9 knockdown significantly inhibited osteoblast-specific gene expression, such as runt-related transcription factor 2 (Runx2), osteocalcin (OCN) and mineral deposition in vitro. Moreover, a total of 950 DEGs were identified in HDAC9-knockdown hBMSCs. We discovered that the MAPK signaling pathway might be related to this process by pathway enrichment analysis. HDAC9 knockdown significantly reduced the expression level of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2). Finally, the decreased osteogenesis due to HDAC9 knockdown was partly rescued by a MAPK signaling pathway activator.Conclusion: Taken together, these results suggest that HDAC9 knockdown inhibits osteogenic differentiation of hBMSCs, partially through the MAPK signaling pathway. HDAC9 may serve as a potential target for the treatment of ONFH.Keywords: HDAC9, hBMSCs, osteogenesis, MAPK signaling pathway

Keywords

• hdac9
• hbmscs
• osteogenesis
• mapk signaling pathway