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

Abstract

Background

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

Data Sharing Statement

All the data in our study will be made available by the authors upon reasonable request from Yong Feng.

Author Contributions

All authors met the following conditions:

1. Made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas.

2. Have drafted or written, or substantially revised or critically reviewed the article.

3. Have agreed on the journal to which the article will be submitted.

4. Reviewed and agreed on all versions of the article before submission, during revision, the final version accepted for publication, and any significant changes introduced at the proofing stage.

5. Agree to take responsibility and be accountable for the contents of the article.

Disclosure

The authors declare no conflicts of interest.

Additional information

Funding

This work is supported by the National Natural Science Foundation of China (No. 81974337) and project of scientific research plan of Wuhan Municipal Health Commission (WX21Q19).