RESUMO
Lineage commitment and tumorigenesis, traits distinguishing stem cells, have not been well characterized and compared in mesenchymal stem cells derived from human dental pulp (DP-MSCs) and bone marrow (BM-MSCs). Here, we report DP-MSCs exhibit increased osteogenic potential, possess decreased adipogenic potential, form dentin pulp-like complexes, and are resistant to oncogenic transformation when compared to BM-MSCs. Genome-wide RNA-seq and differential expression analysis reveal differences in adipocyte and osteoblast differentiation pathways, bone marrow neoplasm pathway, and PTEN/PI3K/AKT pathway. Higher PTEN expression in DP-MSCs than in BM-MSCs is responsible for the lineage commitment and tumorigenesis differences in both cells. Additionally, the PTEN promoter in BM-MSCs exhibits higher DNA methylation levels and repressive mark H3K9Me2 enrichment when compared to DP-MSCs, which is mediated by increased DNMT3B and G9a expression, respectively. The study demonstrates how several epigenetic factors broadly affect lineage commitment and tumorigenesis, which should be considered when developing therapeutic uses of stem cells.
Assuntos
Carcinogênese/genética , Polpa Dentária/citologia , Células-Tronco Mesenquimais/patologia , Osteogênese/genética , PTEN Fosfo-Hidrolase/metabolismo , Adipócitos/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Células da Medula Óssea/patologia , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Carcinogênese/patologia , Diferenciação Celular/genética , Células Cultivadas , Criança , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/genética , Polpa Dentária/patologia , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Antígenos de Histocompatibilidade/metabolismo , Código das Histonas/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Pessoa de Meia-Idade , Osteoblastos/metabolismo , Osteossarcoma/genética , Osteossarcoma/patologia , PTEN Fosfo-Hidrolase/genética , Regiões Promotoras Genéticas/genética , Análise de Sequência de RNA , DNA Metiltransferase 3BRESUMO
STUDY DESIGN: To demonstrate the existence of mesenchymal stem cells (MSCs) in ligamentum flavum (LF) and their pathogenic role in LF hypertrophy. OBJECTIVE: To isolate and characterize LF-derived MSCs and their response to transforming growth factor-beta 1 (TGF-ß1) and trichostatin A (TSA), a histone deacetylase inhibitor (HDACi). SUMMARY OF BACKGROUND DATA: LF is a connective tissue, of which hypertrophic changes induce spinal stenosis. The pathogenic role of TGF-ß1 in spinal stenosis has been implicated. TSA has been shown to suppress TGF-ß1-induced alpha-smooth muscle actin (α-SMA), type I and III collagen synthesis in a variety of cells. MSCs have been isolated from a variety of adult tissues, except LF. Whether MSCs exist in LF and their response to TGF-ß1 and TSA is not clear. METHODS: The MSCs from LF were isolated and cultured. Their phenotypic character, linage differentiation potential, and response to TGF-ß1 and TSA were analyzed. RESULTS: LF-derived MSCs have the similar profile of surface markers as bone marrow MSCs. They were demonstrated to have the potential to be differentiated into osteoblasts, adipocytes, and chondrocytes. Administration of TGF-ß1 stimulated cell proliferation, enhanced the gene expression of type I and III collagen, and increased the gene expression and protein level of α-SMA. TSA blocked the fibrogenic effects of TGF-ß1. CONCLUSION: The current results demonstrated the isolation of MSCs from LF. The cellular response to TGF-ß1 implied that these cells might play an important role in the pathogenesis of LF hypertrophy. TSA, which blocks the effects of TGF-ß1, may be a potent therapeutic choice for inhibiting LF hypertrophy.