Hypoxia Regulates mTORC1-Mediated Keratinocyte Motility and Migration via the AMPK Pathway

PLoS One. 2017 Jan 9;12(1):e0169155. doi: 10.1371/journal.pone.0169155. eCollection 2017.

Abstract

Keratinocyte migration, the initial event and rate-limiting step in wound healing, plays a vital role in restoration of the intact skin barrier, also known as re-epithelialization. After acute tissue injury, hypoxic microenvironment gradually develops and acts as an early stimulus to initiate the healing process. Although we have previously found that hypoxia induces keratinocyte migration, the underlying mechanism remains unknown. Here, we first observed that hypoxia increased mTORC1 activity. Recombinant lentivirus vector and Rapamycin were used for silencing mTORC1 in HaCaT cells and primary mouse keratinocytes (MKs). Using cell migration assay and a Zeiss chamber equipped with imaging system, we also demonstrated that mTORC1 downregulation reversed hypoxia-induced keratinocyte motility and lateral migration. Importantly, hypoxia-activated mTORC1 was accompanied by the AMPK downregulation, and we found that the AMPK pathway activators Metformin (Met) and 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) decreased the mTORC1 activity, cell motility and lateral migration. Thus, our results suggest that hypoxia regulates mTORC1-mediated keratinocyte motility and migration via the AMPK pathway.

MeSH terms

  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • Cell Movement
  • Gene Expression Regulation
  • Humans
  • Hypoxia / metabolism*
  • Keratinocytes / metabolism*
  • Mechanistic Target of Rapamycin Complex 1
  • Mice
  • Multiprotein Complexes / metabolism*
  • RNA, Small Interfering / genetics
  • Signal Transduction*
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Multiprotein Complexes
  • RNA, Small Interfering
  • Mechanistic Target of Rapamycin Complex 1
  • TOR Serine-Threonine Kinases
  • AMP-Activated Protein Kinases

Grants and funding

State Key Development Program for Basic Research of China (No. 2012CB518101) and Research fund of the State Key laboratory of Trauma, Burns and combined injury (No. SKLZZ201203). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.