Involvement of autophagy in hypoxia-BNIP3 signaling to promote epidermal keratinocyte migration

Cell Death Dis. 2019 Mar 8;10(3):234. doi: 10.1038/s41419-019-1473-9.

Abstract

BNIP3 is an atypical BH3-only member of the Bcl-2 family with pro-death, pro-autophagic, and cytoprotective functions, depending on the type of stress and cellular context. Recently, we demonstrated that BNIP3 stimulates the migration of epidermal keratinocytes under hypoxia. In the present study found that autophagy and BNIP3 expression were concomitantly elevated in the migrating epidermis during wound healing in a hypoxia-dependent manner. Inhibition of autophagy through lysosome-specific chemicals (CQ and BafA1) or Atg5-targeted small-interfering RNAs greatly attenuated the hypoxia-induced cell migration, and knockdown of BNIP3 in keratinocytes significantly suppressed hypoxia-induced autophagy activation and cell migration, suggesting a positive role of BNIP3-induced autophagy in keratinocyte migration. Furthermore, these results indicated that the accumulation of reactive oxygen species (ROS) by hypoxia triggered the activation of p38 and JNK mitogen-activated protein kinase (MAPK) in human immortalized keratinocyte HaCaT cells. In turn, activated p38 and JNK MAPK mediated the activation of BNIP3-induced autophagy and the enhancement of keratinocyte migration. These data revealed a previously unknown mechanism that BNIP3-induced autophagy occurs through hypoxia-induced ROS-mediated p38 and JNK MAPK activation and supports the migration of epidermal keratinocytes during wound healing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / physiology*
  • Autophagy-Related Protein 5 / antagonists & inhibitors
  • Autophagy-Related Protein 5 / genetics
  • Autophagy-Related Protein 5 / metabolism
  • Cell Hypoxia
  • Cell Line
  • Cell Movement / physiology
  • Cell Proliferation / physiology
  • Humans
  • Keratinocytes / metabolism*
  • Keratinocytes / ultrastructure
  • MAP Kinase Kinase 4 / genetics
  • MAP Kinase Kinase 4 / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Wound Healing / genetics
  • Wound Healing / physiology
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • ATG5 protein, human
  • Atg5 protein, mouse
  • Autophagy-Related Protein 5
  • BNIP3 protein, human
  • BNip3 protein, mouse
  • Membrane Proteins
  • Mitochondrial Proteins
  • Proto-Oncogene Proteins
  • Reactive Oxygen Species
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 4