CDK1-PDK1-PI3K/Akt signaling pathway regulates embryonic and induced pluripotency

Cell Death Differ. 2017 Jan;24(1):38-48. doi: 10.1038/cdd.2016.84. Epub 2016 Sep 16.

Abstract

The mechanisms of how signaling pathways are coordinated and integrated for the maintenance of the self-renewal of human embryonic stem cells (hESCs) and the acquisition of pluripotency in reprogramming are still only partly understood. CDK1 is a key regulator of mitosis. Recently, CDK1 has been shown to be involved in regulating self-renewal of stem cells, even though the mechanistic role of how CDK1 regulates pluripotency is unknown. In this report, we aim to understand how CDK1 can control pluripotency by reducing CDK1 activity to a level that has no effect on cell cycle progression. We demonstrated that high levels of CDK1 is associated with the pluripotency stage of hESCs; and decreased CDK1 activity to a level without perturbing the cell cycle is sufficient to induce differentiation. CDK1 specifically targets the phosphorylation of PDK1 and consequently the activity of PI3K/Akt and its effectors ERK and GSK3β. Evidence of the reversion of inactive CDK1-mediated differentiation by the inhibition of Akt signaling effectors suggests that the CDK1-PDK1-PI3K/Akt kinase cascade is a functional signaling pathway for the pluripotency of hESCs. Moreover, cyclin B1-CDK1 complexes promote somatic reprogramming efficiency, probably by regulating the maturation of induced pluripotent stem cells (iPSCs), as cyclin B1 stimulates a higher cellular level of LIN28A, suggesting that monitoring iPSC factors could be a new path for the enhancement of reprogramming efficiency. Together, we demonstrate an essential role for the CDK1-PDK1-PI3K/Akt kinase signaling pathway in the regulation of self-renewal, differentiation, and somatic reprogramming, which provides a novel kinase cascade mechanism for pluripotency control and acquisition.

MeSH terms

  • CDC2 Protein Kinase / antagonists & inhibitors
  • CDC2 Protein Kinase / genetics
  • CDC2 Protein Kinase / metabolism*
  • Cell Differentiation / drug effects
  • Cell Self Renewal
  • Cellular Reprogramming
  • Down-Regulation / drug effects
  • Glycogen Synthase Kinase 3 beta / metabolism
  • HEK293 Cells
  • Human Embryonic Stem Cells
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / metabolism
  • Nanog Homeobox Protein / antagonists & inhibitors
  • Nanog Homeobox Protein / genetics
  • Nanog Homeobox Protein / metabolism
  • Octamer Transcription Factor-3 / antagonists & inhibitors
  • Octamer Transcription Factor-3 / genetics
  • Octamer Transcription Factor-3 / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphorylation / drug effects
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Pyruvate Dehydrogenase Acetyl-Transferring Kinase
  • Quinolines / pharmacology
  • RNA Interference
  • Signal Transduction / drug effects
  • Thiazoles / pharmacology
  • Tretinoin / pharmacology

Substances

  • Nanog Homeobox Protein
  • Octamer Transcription Factor-3
  • PDK1 protein, human
  • POU5F1 protein, human
  • Pyruvate Dehydrogenase Acetyl-Transferring Kinase
  • Quinolines
  • RO 3306
  • Thiazoles
  • Tretinoin
  • Glycogen Synthase Kinase 3 beta
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • CDC2 Protein Kinase
  • CDK1 protein, human