Dissecting dual roles of MyoD during lineage conversion to mature myocytes and myogenic stem cells
Open Access
- 19 August 2021
- journal article
- research article
- Published by Cold Spring Harbor Laboratory in Genes & Development
- Vol. 35 (17-18), 1209-1228
- https://doi.org/10.1101/gad.348678.121
Abstract
The generation of myotubes from fibroblasts upon forced MyoD expression is a classic example of transcription factor-induced reprogramming. We recently discovered that additional modulation of signaling pathways with small molecules facilitates reprogramming to more primitive induced myogenic progenitor cells (iMPCs). Here, we dissected the transcriptional and epigenetic dynamics of mouse fibroblasts undergoing reprogramming to either myotubes or iMPCs using a MyoD-inducible transgenic model. Induction of MyoD in fibroblasts combined with small molecules generated Pax7+ iMPCs with high similarity to primary muscle stem cells. Analysis of intermediate stages of iMPC induction revealed that extinction of the fibroblast program preceded induction of the stem cell program. Moreover, key stem cell genes gained chromatin accessibility prior to their transcriptional activation, and these regions exhibited a marked loss of DNA methylation dependent on the Tet enzymes. In contrast, myotube generation was associated with few methylation changes, incomplete and unstable reprogramming, and an insensitivity to Tet depletion. Finally, we showed that MyoD's ability to bind to unique bHLH targets was crucial for generating iMPCs but dispensable for generating myotubes. Collectively, our analyses elucidate the role of MyoD in myogenic reprogramming and derive general principles by which transcription factors and signaling pathways cooperate to rewire cell identity.Keywords
Funding Information
- Uehara Memorial Foundation Research Fellowship
- Mochida Memorial Foundation Research Fellowship
- Japan Society for the Promotion of Science (Overseas Research Fellowship)
- National Institutes of Health (R01AR076394)
- NIH (T32 DK007260)
- NIH (3R01AG048917-02S1)
- Burroughs Wellcome Fund
- Glenn Foundation for Medical Research
- NIH (R01 AG048917, DP1 AG063419)
- Dana-Farber Cancer Institute's Center for Cancer Evolution and Physical Sciences-Oncology Center (U54CA193461, P30 DK040561)
- NIH
- Massachusetts General Hospital
- NIH (R01 HD058013, R01AR077695, P01 GM099134)
- Gerald and Darlene Jordan Chair in Regenerative Medicine
This publication has 55 references indexed in Scilit:
- Tissue-Specific Stem Cells: Lessons from the Skeletal Muscle Satellite CellCell Stem Cell, 2012
- Direct Lineage Conversion of Terminally Differentiated Hepatocytes to Functional NeuronsCell Stem Cell, 2011
- De novo DNA methylation by Dnmt3a and Dnmt3b is dispensable for nuclear reprogramming of somatic cells to a pluripotent stateGenes & Development, 2011
- Genome-wide MyoD Binding in Skeletal Muscle Cells: A Potential for Broad Cellular ReprogrammingDevelopmental Cell, 2010
- Tgfβ Signal Inhibition Cooperates in the Induction of iPSCs and Replaces Sox2 and cMycCurrent Biology, 2009
- Self-renewal and expansion of single transplanted muscle stem cellsNature, 2008
- Highly Efficient, Functional Engraftment of Skeletal Muscle Stem Cells in Dystrophic MusclesCell, 2008
- PU.1 and C/EBPα/β convert fibroblasts into macrophage-like cellsProceedings of the National Academy of Sciences of the United States of America, 2008
- Derivation of completely cell culture-derived mice from early-passage embryonic stem cells.Proceedings of the National Academy of Sciences of the United States of America, 1993
- Expression of a single transfected cDNA converts fibroblasts to myoblastsCell, 1987