Inhibiting cytosolic translation and autophagy improves health in mitochondrial disease

Hum Mol Genet. 2015 Sep 1;24(17):4829-47. doi: 10.1093/hmg/ddv207. Epub 2015 Jun 3.

Abstract

Mitochondrial respiratory chain (RC) disease therapies directed at intra-mitochondrial pathology are largely ineffective. Recognizing that RC dysfunction invokes pronounced extra-mitochondrial transcriptional adaptations, particularly involving dysregulated translation, we hypothesized that translational dysregulation is itself contributing to the pathophysiology of RC disease. Here, we investigated the activities, and effects from direct inhibition, of a central translational regulator (mTORC1) and its downstream biological processes in diverse genetic and pharmacological models of RC disease. Our data identify novel mechanisms underlying the cellular pathogenesis of RC dysfunction, including the combined induction of proteotoxic stress, the ER stress response and autophagy. mTORC1 inhibition with rapamycin partially ameliorated renal disease in B6.Pdss2(kd/kd) mice with complexes I-III/II-III deficiencies, improved viability and mitochondrial physiology in gas-1(fc21) nematodes with complex I deficiency, and rescued viability across a variety of RC-inhibited human cells. Even more effective was probucol, a PPAR-activating anti-lipid drug that we show also inhibits mTORC1. However, directly inhibiting mTORC1-regulated downstream activities yielded the most pronounced and sustained benefit. Partial inhibition of translation by cycloheximide, or of autophagy by lithium chloride, rescued viability, preserved cellular respiratory capacity and induced mitochondrial translation and biogenesis. Cycloheximide also ameliorated proteotoxic stress via a uniquely selective reduction of cytosolic protein translation. RNAseq-based transcriptome profiling of treatment effects in gas-1(fc21) mutants provide further evidence that these therapies effectively restored altered translation and autophagy pathways toward that of wild-type animals. Overall, partially inhibiting cytosolic translation and autophagy offer novel treatment strategies to improve health across the diverse array of human diseases whose pathogenesis involves RC dysfunction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy* / drug effects
  • Autophagy* / genetics
  • Cell Survival / drug effects
  • Cycloheximide / pharmacology
  • Cytosol
  • Disease Models, Animal
  • Electron Transport
  • Endoplasmic Reticulum Stress / drug effects
  • Enzyme Activation
  • Gene Expression Profiling
  • Humans
  • Mechanistic Target of Rapamycin Complex 1
  • Mice
  • Mice, Knockout
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondrial Diseases / genetics*
  • Mitochondrial Diseases / metabolism*
  • Models, Biological
  • Multiprotein Complexes / metabolism
  • Phosphorylation
  • Probucol / pharmacology
  • Protein Biosynthesis* / drug effects
  • Ribosomal Protein S6 Kinases / metabolism
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases / metabolism
  • Transcriptome

Substances

  • Multiprotein Complexes
  • Cycloheximide
  • TOR Serine-Threonine Kinases
  • Mechanistic Target of Rapamycin Complex 1
  • Ribosomal Protein S6 Kinases
  • Probucol
  • Sirolimus

Associated data

  • BioProject/PRJNA284422