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Epigenetic dysregulation in mesenchymal stem cell aging and spontaneous differentiation.

Li Z, Liu C, Xie Z, Song P, Zhao RC, Guo L, Liu Z, Wu Y - PLoS ONE (2011)

Bottom Line: We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP.Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly.Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation.

View Article: PubMed Central - PubMed

Affiliation: Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.

ABSTRACT

Background: Mesenchymal stem cells (MSCs) hold great promise for the treatment of difficult diseases. As MSCs represent a rare cell population, ex vivo expansion of MSCs is indispensable to obtain sufficient amounts of cells for therapies and tissue engineering. However, spontaneous differentiation and aging of MSCs occur during expansion and the molecular mechanisms involved have been poorly understood.

Methodology/principal findings: Human MSCs in early and late passages were examined for their expression of genes involved in osteogenesis to determine their spontaneous differentiation towards osteoblasts in vitro, and of genes involved in self-renewal and proliferation for multipotent differentiation potential. In parallel, promoter DNA methylation and hostone H3 acetylation levels were determined. We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP. Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly. Notably, the altered expression of these genes were closely associated with epigenetic dysregulation of histone H3 acetylation in K9 and K14, but not with methylation of CpG islands in the promoter regions of most of these genes. bFGF promoted MSC proliferation and suppressed its spontaneous osteogenic differentiation, with corresponding changes in histone H3 acetylation in TERT, Oct4, Sox2, Runx2 and ALP genes.

Conclusions/significance: Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation.

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Differentiation of MSCs.Cultured in appropriate induction media, (A & B) MSCs differentiated into adipocytes (after oil red staining, A represents non-induced and B represents induced), (C & D) osteoblasts (after Alizarin Red S staining, C represents non-induced and D represents induced), and (E & F) chondrocytes (after Alcian Blue staining, E represents non-induced and F represents induced).
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pone-0020526-g002: Differentiation of MSCs.Cultured in appropriate induction media, (A & B) MSCs differentiated into adipocytes (after oil red staining, A represents non-induced and B represents induced), (C & D) osteoblasts (after Alizarin Red S staining, C represents non-induced and D represents induced), and (E & F) chondrocytes (after Alcian Blue staining, E represents non-induced and F represents induced).

Mentions: Fluorescence activated cell sorting (FACS) analysis of our MSCs showed that they were negative for lineage cell markers such as CD34 and CD45, and were strongly positive for CD105, CD73 and CD90, exhibiting typical immunophenotypic features of MSCs (Fig. 1). The cells also expressed CD51 and CD61 (Fig. 1). After induction in appropriate media, MSCs differentiated into adipocytes (Fig. 2B), osteoblasts (Fig. 2D) and chondrocytes (Fig. 2F).


Epigenetic dysregulation in mesenchymal stem cell aging and spontaneous differentiation.

Li Z, Liu C, Xie Z, Song P, Zhao RC, Guo L, Liu Z, Wu Y - PLoS ONE (2011)

Differentiation of MSCs.Cultured in appropriate induction media, (A & B) MSCs differentiated into adipocytes (after oil red staining, A represents non-induced and B represents induced), (C & D) osteoblasts (after Alizarin Red S staining, C represents non-induced and D represents induced), and (E & F) chondrocytes (after Alcian Blue staining, E represents non-induced and F represents induced).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111432&req=5

pone-0020526-g002: Differentiation of MSCs.Cultured in appropriate induction media, (A & B) MSCs differentiated into adipocytes (after oil red staining, A represents non-induced and B represents induced), (C & D) osteoblasts (after Alizarin Red S staining, C represents non-induced and D represents induced), and (E & F) chondrocytes (after Alcian Blue staining, E represents non-induced and F represents induced).
Mentions: Fluorescence activated cell sorting (FACS) analysis of our MSCs showed that they were negative for lineage cell markers such as CD34 and CD45, and were strongly positive for CD105, CD73 and CD90, exhibiting typical immunophenotypic features of MSCs (Fig. 1). The cells also expressed CD51 and CD61 (Fig. 1). After induction in appropriate media, MSCs differentiated into adipocytes (Fig. 2B), osteoblasts (Fig. 2D) and chondrocytes (Fig. 2F).

Bottom Line: We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP.Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly.Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation.

View Article: PubMed Central - PubMed

Affiliation: Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.

ABSTRACT

Background: Mesenchymal stem cells (MSCs) hold great promise for the treatment of difficult diseases. As MSCs represent a rare cell population, ex vivo expansion of MSCs is indispensable to obtain sufficient amounts of cells for therapies and tissue engineering. However, spontaneous differentiation and aging of MSCs occur during expansion and the molecular mechanisms involved have been poorly understood.

Methodology/principal findings: Human MSCs in early and late passages were examined for their expression of genes involved in osteogenesis to determine their spontaneous differentiation towards osteoblasts in vitro, and of genes involved in self-renewal and proliferation for multipotent differentiation potential. In parallel, promoter DNA methylation and hostone H3 acetylation levels were determined. We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP. Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly. Notably, the altered expression of these genes were closely associated with epigenetic dysregulation of histone H3 acetylation in K9 and K14, but not with methylation of CpG islands in the promoter regions of most of these genes. bFGF promoted MSC proliferation and suppressed its spontaneous osteogenic differentiation, with corresponding changes in histone H3 acetylation in TERT, Oct4, Sox2, Runx2 and ALP genes.

Conclusions/significance: Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation.

Show MeSH