Impairment of autophagic flux promotes glucose reperfusion-induced neuro2A cell death after glucose deprivation

PLoS One. 2013 Oct 4;8(10):e76466. doi: 10.1371/journal.pone.0076466. eCollection 2013.

Abstract

Hypoglycemia-induced brain injury is a common and serious complication of intensive insulin therapy experienced by Type 1 diabetic patients. We previously reported that hypoglycemic neuronal death is triggered by glucose reperfusion after hypoglycemia rather than as a simple result of glucose deprivation. However, the precise mechanism of neuronal death initiated by glucose reperfusion is still unclear. Autophagy is a self-degradation process that acts through a lysosome-mediated trafficking pathway to degrade and recycle intracellular components, thereby regulating metabolism and energy production. Recent studies suggest that autophagic and lysosomal dysfunction leads to abnormal protein degradation and deposition that may contribute to neuronal death. Here, we focused on the relationship between autophagy and lysosomal dysfunction in hypoglycemia-induced neuronal death. In neuronal cells, glucose reperfusion after glucose deprivation resulted in inhibition of autophagy, which may promote cell death. This cell death was accompanied with activation of caspase3 and the lysosomal proteases cathepsin B and D, which indicated impairment of autophagic flux. Taken together, these results suggest that interplay of autophagy, caspase3 activation and lysosomal proteases serve as a basis for neuronal death after hypoglycemia. Thus, we provide the molecular mechanism of neuronal death by glucose reperfusion and suggest some clues for therapeutic strategies to prevent hypoglycemia-induced neuronal death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy* / drug effects
  • Caspase 3 / metabolism
  • Cathepsin B / genetics
  • Cathepsin B / metabolism
  • Cathepsin D / genetics
  • Cathepsin D / metabolism
  • Cell Death / drug effects
  • Cell Line, Tumor
  • Enzyme Activation / drug effects
  • Gene Expression Regulation / drug effects
  • Glucose / metabolism*
  • Glucose / pharmacology
  • Mice
  • Neurons / drug effects
  • Neurons / metabolism*
  • Neurons / ultrastructure
  • Reperfusion

Substances

  • Caspase 3
  • Cathepsin B
  • Cathepsin D
  • Glucose

Grants and funding

This work was supported by the Korea Healthcare Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (A120202) and by a grant from the Hallym University Specialization Fund (HRF-S-41) to S.W.S. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.