Mitophagy-dependent necroptosis contributes to the pathogenesis of COPD

J Clin Invest. 2014 Sep;124(9):3987-4003. doi: 10.1172/JCI74985. Epub 2014 Aug 1.

Abstract

The pathogenesis of chronic obstructive pulmonary disease (COPD) remains unclear, but involves loss of alveolar surface area (emphysema) and airway inflammation (bronchitis) as the consequence of cigarette smoke (CS) exposure. Previously, we demonstrated that autophagy proteins promote lung epithelial cell death, airway dysfunction, and emphysema in response to CS; however, the underlying mechanisms have yet to be elucidated. Here, using cultured pulmonary epithelial cells and murine models, we demonstrated that CS causes mitochondrial dysfunction that is associated with a reduction of mitochondrial membrane potential. CS induced mitophagy, the autophagy-dependent elimination of mitochondria, through stabilization of the mitophagy regulator PINK1. CS caused cell death, which was reduced by administration of necrosis or necroptosis inhibitors. Genetic deficiency of PINK1 and the mitochondrial division/mitophagy inhibitor Mdivi-1 protected against CS-induced cell death and mitochondrial dysfunction in vitro and reduced the phosphorylation of MLKL, a substrate for RIP3 in the necroptosis pathway. Moreover, Pink1(-/-) mice were protected against mitochondrial dysfunction, airspace enlargement, and mucociliary clearance (MCC) disruption during CS exposure. Mdivi-1 treatment also ameliorated CS-induced MCC disruption in CS-exposed mice. In human COPD, lung epithelial cells displayed increased expression of PINK1 and RIP3. These findings implicate mitophagy-dependent necroptosis in lung emphysematous changes in response to CS exposure, suggesting that this pathway is a therapeutic target for COPD.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis*
  • Cells, Cultured
  • Dynamins / physiology
  • Membrane Potential, Mitochondrial
  • Mice
  • Mice, Inbred C57BL
  • Mitochondria / physiology
  • Mitophagy / physiology*
  • Necrosis
  • Nicotiana / adverse effects
  • Protein Kinases / physiology
  • Pulmonary Disease, Chronic Obstructive / etiology*
  • Quinazolinones / pharmacology
  • Smoke / adverse effects
  • Ubiquitin-Protein Ligases / physiology

Substances

  • 3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone
  • Quinazolinones
  • Smoke
  • Ubiquitin-Protein Ligases
  • parkin protein
  • Protein Kinases
  • PTEN-induced putative kinase
  • Dnm1l protein, mouse
  • Dynamins