SOX2 has a crucial role in the lineage determination and proliferation of mesenchymal stem cells through Dickkopf-1 and c-MYC.
SOX2 is a well-known core transcription factor in embryonic stem cells (ESCs) and has an important role in the maintenance of pluripotency. Recently, SOX2 expression has also been reported in adult stem cells (ASCs), but the role of SOX2 in ASCs remains unknown. In this study, we examined the molecular mechanisms of SOX2 in human mesenchymal stem cells (hMSCs), a type of ASCs, by performing inhibition studies. SOX2 inhibition resulted in altered cell growth and differentiation capabilities. These changes coincided with a decrease in Dickkopf-1 (DKK1), a soluble inhibitor of WNT signaling. Chromatin immunoprecipitation and luciferase assays showed that SOX2 binds to DKK1 and has a positive regulatory role in transcription. The enforced expression of DKK1 in SOX2-inhibited hMSCs reversed the differentiation deformities, but could not abrogate the cell proliferation defect. Proliferation was regulated by c-MYC, whose expression can also be controlled by SOX2. Our study shows that SOX2 directly regulates DKK1 expression and, as a consequence, determines the differentiation lineage of hMSCs. Moreover, SOX2 also regulates proliferation by affecting c-MYC. Therefore, these results suggest that SOX2 might have a specific function by regulating DKK1 and c-MYC in the differentiation and growth of ASCs, which is separate from its roles in ESCs.
Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
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SB
Park
K W
KW
Seo
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So
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MS
Seo
K R
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Yu
S K
SK
Kang
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Kang
D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D055748:SOXB1 Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology
C501126:DKK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors