Reversible Keap1 inhibitors are preferential pharmacological tools to modulate cellular mitophagy

Sci Rep. 2017 Sep 4;7(1):10303. doi: 10.1038/s41598-017-07679-7.

Abstract

Mitophagy orchestrates the autophagic degradation of dysfunctional mitochondria preventing their pathological accumulation and contributing to cellular homeostasis. We previously identified a novel chemical tool (hereafter referred to as PMI), which drives mitochondria into autophagy without collapsing their membrane potential (ΔΨm). PMI is an inhibitor of the protein-protein interaction (PPI) between the transcription factor Nrf2 and its negative regulator, Keap1 and is able to up-regulate the expression of autophagy-associated proteins, including p62/SQSTM1. Here we show that PMI promotes mitochondrial respiration, leading to a superoxide-dependent activation of mitophagy. Structurally distinct Keap1-Nrf2 PPI inhibitors promote mitochondrial turnover, while covalent Keap1 modifiers, including sulforaphane (SFN) and dimethyl fumarate (DMF), are unable to induce a similar response. Additionally, we demonstrate that SFN reverses the effects of PMI in co-treated cells by reducing the accumulation of p62 in mitochondria and subsequently limiting their autophagic degradation. This study highlights the unique features of Keap1-Nrf2 PPI inhibitors as inducers of mitophagy and their potential as pharmacological agents for the treatment of pathological conditions characterized by impaired mitochondrial quality control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects*
  • Cell Line, Tumor
  • Fibroblasts
  • Humans
  • Kelch-Like ECH-Associated Protein 1 / antagonists & inhibitors*
  • Membrane Potential, Mitochondrial / drug effects
  • Mice
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Models, Biological
  • Oxidation-Reduction
  • Oxidative Stress
  • Oxygen Consumption
  • Reactive Oxygen Species / metabolism
  • Superoxides / metabolism
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • Kelch-Like ECH-Associated Protein 1
  • MAP1LC3A protein, human
  • Microtubule-Associated Proteins
  • Reactive Oxygen Species
  • Superoxides
  • Ubiquitin-Protein Ligases
  • parkin protein