title: cAMP and EPAC Signaling Functionally Replace OCT4 During Induced Pluripotent Stem Cell Reprogramming.
abstract: The advent of induced pluripotent stem cells--generated via the ectopic overexpression of reprogramming factors such as OCT4, SOX2, KLF4, and C-MYC (OSKM) in a differentiated cell type--has enabled groundbreaking research efforts in regenerative medicine, disease modeling, and drug discovery. Although initial studies have focused on the roles of nuclear factors, increasing evidence highlights the importance of signal transduction during reprogramming. By utilizing a quantitative, medium-throughput screen to initially identify signaling pathways that could potentially replace individual transcription factors during reprogramming, we initially found that several pathways--such as Notch, Smoothened, and cyclic AMP (cAMP) signaling--were capable of generating alkaline phosphatase positive colonies in the absence of OCT4, the most stringently required Yamanaka factor. After further investigation, we discovered that cAMP signal activation could functionally replace OCT4 to induce pluripotency, and results indicate that the downstream exchange protein directly activated by cAMP (EPAC) signaling pathway rather than protein kinase A (PKA) signaling is necessary and sufficient for this function. cAMP signaling may reduce barriers to reprogramming by contributing to downstream epithelial gene expression, decreasing mesenchymal gene expression, and increasing proliferation. Ultimately, these results elucidate mechanisms that could lead to new reprogramming methodologies and advance our understanding of stem cell biology.
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors: Ashley L
authors: AL
authors: Fritz
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors: Maroof M
authors: MM
authors: Adil
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors: Sunnie R
authors: SR
authors: Mao
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA; Department of Bioengineering, University of California, Berkeley, California, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, California, USA. Electronic address: schaffer@berkeley.edu.
authors: David V
authors: DV
authors: Schaffer
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D065150:Cellular Reprogramming; D005576:Colforsin / Q000494:pharmacology; D003114:Colony-Forming Units Assay; D000242:Cyclic AMP / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic; D019076:Transgenes
chemical_list: D020662:Guanine Nucleotide Exchange Factors; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D050814:Octamer Transcription Factor-3; C116122:RAPGEF3 protein, human; D005576:Colforsin; D000242:Cyclic AMP; D000469:Alkaline Phosphatase; D000262:Adenylyl Cyclases