MicroRNAs Enhance Keratinocyte Proliferative Capacity in a Stem Cell-Enriched Epithelium

PLoS One. 2015 Aug 6;10(8):e0134853. doi: 10.1371/journal.pone.0134853. eCollection 2015.

Abstract

MicroRNAs are critical regulators of stem cell behavior. The miR-103/107 family is preferentially expressed in the stem cell-enriched corneal limbal epithelium and plays an important role in coordinating several intrinsic characteristics of limbal epithelial stem cells. To elucidate further the mechanisms by which miRs-103/107 function in regulating limbal epithelial stem cells, we investigate the global effects of miRs-103/107 on gene expression in an unbiased manner. Using antagomirs-103/107, we knocked down endogenous miRs-103/107 in keratinocytes and conducted an mRNA profiling study. We show that miRs-103/107 target mitogen-activated protein kinase kinase kinase 7 (MAP3K7) and thereby negatively regulate the p38/AP-1 pathway, which directs epithelial cells towards a differentiated state. Pharmacological inhibition of p38 increases holoclone colony formation, a measure of proliferative capacity. This suggests that the negative regulation of p38 by miRs-103/107 contributes to enhanced proliferative capacity, which is a hallmark of stem cells. Since miRs-103/107 also promote increased holoclone colony formation by regulating JNK activation through non-canonical Wnt signaling, we believe that this microRNA family preserves "stemness" by mediating the crosstalk between the Wnt/JNK and MAP3K7/p38/AP-1 pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cell Proliferation
  • Cells, Cultured
  • Female
  • Gene Regulatory Networks
  • Humans
  • Keratinocytes / cytology*
  • Keratinocytes / metabolism
  • Limbus Corneae / cytology
  • MAP Kinase Kinase Kinases / chemistry
  • MAP Kinase Kinase Kinases / genetics
  • MAP Kinase Kinase Kinases / metabolism
  • Mice
  • Mice, Inbred BALB C
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Oligonucleotides, Antisense / metabolism
  • Sequence Alignment
  • Signal Transduction
  • Stem Cells / cytology*
  • Transcription Factor AP-1 / metabolism
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • MIRN103 microRNA, mouse
  • MIRN107 microRNA, mouse
  • MicroRNAs
  • Oligonucleotides, Antisense
  • Transcription Factor AP-1
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinases
  • MAP kinase kinase kinase 7