RhoA promotes epidermal stem cell proliferation via PKN1-cyclin D1 signaling

PLoS One. 2017 Feb 21;12(2):e0172613. doi: 10.1371/journal.pone.0172613. eCollection 2017.

Abstract

Objective: Epidermal stem cells (ESCs) play a critical role in wound healing, but the mechanism underlying ESC proliferation is not well defined. Here, we explore the effects of RhoA on ESC proliferation and the possible underlying mechanism.

Methods: Human ESCs were enriched by rapid adhesion to collagen IV. RhoA(+/+)(G14V), RhoA(-/-)(T19N) and pGFP control plasmids were transfected into human ESCs. The effect of RhoA on cell proliferation was detected by cell proliferation and DNA synthesis assays. Induction of PKN1 activity by RhoA was determined by immunoblot analysis, and the effects of PKN1 on RhoA in terms of inducing cell proliferation and cyclin D1 expression were detected using specific siRNA targeting PKN1. The effects of U-46619 (a RhoA agonist) and C3 transferase (a RhoA antagonist) on ESC proliferation were observed in vivo.

Results: RhoA had a positive effect on ESC proliferation, and PKN1 activity was up-regulated by the active RhoA mutant (G14V) and suppressed by RhoA T19N. Moreover, the ability of RhoA to promote ESC proliferation and DNA synthesis was interrupted by PKN1 siRNA. Additionally, cyclin D1 protein and mRNA expression levels were up-regulated by RhoA G14V, and these effects were inhibited by siRNA-mediated knock-down of PKN1. RhoA also promoted ESC proliferation via PKN in vivo.

Conclusion: This study shows that the effect of RhoA on ESC proliferation is mediated by activation of the PKN1-cyclin D1 pathway in vitro, suggesting that RhoA may serve as a new therapeutic target for wound healing.

MeSH terms

  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / pharmacology
  • ADP Ribose Transferases / pharmacology
  • Animals
  • Botulinum Toxins / pharmacology
  • Burns / physiopathology
  • Burns / therapy
  • Carbazoles / pharmacology
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Cyclin D1 / biosynthesis
  • Cyclin D1 / genetics
  • Cyclin D1 / physiology*
  • DNA Replication / drug effects
  • Epidermal Cells*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Humans
  • Indole Alkaloids / pharmacology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mutation, Missense
  • Primary Cell Culture
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / genetics
  • Protein Kinase C / physiology*
  • RNA Interference
  • RNA, Small Interfering
  • Random Allocation
  • Signal Transduction / physiology*
  • Stem Cells / cytology
  • Stem Cells / metabolism*
  • Transfection
  • Wound Healing* / physiology
  • rho GTP-Binding Proteins / agonists
  • rho GTP-Binding Proteins / antagonists & inhibitors
  • rhoA GTP-Binding Protein / deficiency
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / physiology*

Substances

  • CCND1 protein, human
  • Carbazoles
  • Indole Alkaloids
  • RNA, Small Interfering
  • RHOA protein, human
  • Cyclin D1
  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
  • staurosporine aglycone
  • ADP Ribose Transferases
  • exoenzyme C3, Clostridium botulinum
  • protein kinase N
  • Protein Kinase C
  • Botulinum Toxins
  • RhoA protein, mouse
  • rho GTP-Binding Proteins
  • rhoA GTP-Binding Protein

Grant support

This work was supported by the National Natural Science Foundation of China (no. 81272121). The funders had no roles in study design, data collection and analysis, decision to publish, or preparation of the manuscript.