Romidepsin Promotes Osteogenic and Adipocytic Differentiation of Human Mesenchymal Stem Cells through Inhibition of Histondeacetylase Activity

Epigenetic control of mesenchymal stem cells orchestrates bone regeneration

Recent studies have revealed the vital role of MSCs in bone regeneration. In both self-healing bone regeneration processes and biomaterial-induced healing of bone defects beyond the critical size, MSCs show several functions, including osteogenic differentiation and thus providing seed cells. However, adverse factors such as drug intake and body senescence can significantly affect the functions of MSCs in bone regeneration. Currently, several modalities have been developed to regulate MSCs' phenotype and promote the bone regeneration process. Epigenetic regulation has received much attention because of its heritable nature. Indeed, epigenetic regulation of MSCs is involved in the pathogenesis of a variety of disorders of bone metabolism. Moreover, studies using epigenetic regulation to treat diseases are also being reported. At the same time, the effects of epigenetic regulation on MSCs are yet to be fully understood. This review focuses on recent advances in the effects of epigenetic regulation on osteogenic differentiation, proliferation, and cellular senescence in MSCs. We intend to illustrate how epigenetic regulation of MSCs orchestrates the process of bone regeneration.

Bone morphogenetic protein-7 upregulates genes associated with osteoblast differentiation, including collagen I, Sp7 and IBSP in gingiva-derived stem cells

The present study was performed to evaluate the effects of short-term application of bone morphogenetic protein-7 (BMP-7) on human gingiva-derived mesenchymal stem cells with next-generation sequencing. Human gingiva-derived stem cells were treated with a final concentration of 100 ng/ml BMP-7 and the same concentration of a vehicle control. mRNA sequencing and data analysis were performed along using gene ontology and pathway analysis. RT-qPCR of mRNA of collagen I, Sp7, IBSP and western blot analysis of collagen I, osterix and bone sialoprotein was also performed. A total of 25,737 mRNAs were identified to be differentially expressed. Regarding osteoblast differentiation, 14 mRNAs were upregulated and 10 were downregulated when the results of the BMP-7 at 3 h were compared with the control at 3 h. The expression of collagen I was increased following the application of BMP-7 at 3 h, and this increase was also observed following western blot analysis. The effects of BMP-7 on stem cells were evaluated with mRNA sequencing, and the expression was validated with RT-qPCR and western blot analysis. The short-term application of BMP-7 produced an increased expression of collagen I, which was associated with target genes selected for osteoblast differentiation. This study may provide novel insights into the role of BMP-7 using mRNA sequencing.

Convergence of TGFβ and BMP signaling in regulating human bone marrow stromal cell differentiation

Targeting regulatory signaling pathways that control human bone marrow stromal (skeletal or mesenchymal) stem cell (hBMSC) differentiation and lineage fate determination is gaining momentum in the regenerative medicine field. Therefore, to identify the central regulatory mechanism of osteoblast differentiation of hBMSCs, the molecular phenotypes of two clonal hBMSC lines exhibiting opposite in vivo phenotypes, namely, bone forming (hBMSC^+bone) and non-bone forming (hBMSC^−Bone) cells, were studied. Global transcriptome analysis revealed significant downregulation of several TGFβ responsive genes, namely, TAGLN, TMP1, ACTA2, TGFβ2, SMAD6, SMAD9, BMP2, and BMP4 in hBMSC^−Bone cells and upregulation on SERPINB2 and NOG. Transcriptomic data was associated with marked reduction in SMAD2 protein phosphorylation, which thereby implies the inactivation of TGFβ and BMP signaling in those cells. Concordantly, activation of TGFβ signaling in hBMSC^−Bone cells using either recombinant TGFβ1 protein or knockdown of SERPINB2 TGFβ-responsive gene partially restored their osteoblastic differentiation potential. Similarly, the activation of BMP signaling using exogenous BMP4 or via siRNA-mediated knockdown of NOG partially restored the differentiation phenotype of hBMSC^−Bone cells. Concordantly, recombinant NOG impaired ex vivo osteoblastic differentiation of hBMSC^+Bone cells, which was associated with SERBINB2 upregulation. Our data suggests the existence of reciprocal relationship between TGFB and BMP signaling that regulates hBMSC lineage commitment and differentiation, whilst provide a plausible strategy for generating osteoblastic committed cells from hBMSCs for clinical applications.