Reducing mitochondrial ROS improves disease-related pathology in a mouse model of ataxia-telangiectasia

Mol Ther. 2013 Jan;21(1):42-8. doi: 10.1038/mt.2012.203. Epub 2012 Sep 25.

Abstract

The disease ataxia-telangiectasia (A-T) has no cure and few treatment options. It is caused by mutations in the ATM kinase, which functions in the DNA-damage response and redox sensing. In addition to severe cerebellar degeneration, A-T pathology includes cancer predisposition, sterility, immune system dysfunction, and bone marrow abnormalities. These latter phenotypes are recapitulated in the ATM null (ATM(-/-)) mouse model of the disease. Since oxidative stress and mitochondrial dysfunction are implicated in A-T, we determined whether reducing mitochondrial reactive oxygen species (ROS) via overexpression of catalase targeted to mitochondria (mCAT) alleviates A-T-related pathology in ATM(-/-) mice. We found that mCAT has many beneficial effects in this context, including reduced propensity to develop thymic lymphoma, improved bone marrow hematopoiesis and macrophage differentiation in vitro, and partial rescue of memory T-cell developmental defects. Our results suggest that positive effects observed on cancer development may be linked to mCAT reducing mitochondrial ROS, lactate production, and TORC1 signaling in transforming double-positive cells, whereas beneficial effects in memory T cells appear to be TORC1-independent. Altogether, this study provides proof-of-principle that reducing mitochondrial ROS production per se may be therapeutic for the disease, which may have advantages compared with more general antioxidant strategies.

Publication types

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

MeSH terms

  • Animals
  • Ataxia Telangiectasia / metabolism
  • Ataxia Telangiectasia / pathology*
  • Ataxia Telangiectasia Mutated Proteins
  • CD8-Positive T-Lymphocytes / immunology
  • Catalase / metabolism
  • Cell Cycle Proteins / genetics
  • DNA-Binding Proteins / genetics
  • Disease Models, Animal*
  • Hematopoiesis
  • Immunologic Memory
  • Lymphoma / enzymology
  • Mice
  • Mice, Knockout
  • Mitochondria / enzymology
  • Mitochondria / metabolism*
  • Protein-Serine-Threonine Kinases / genetics
  • Reactive Oxygen Species / metabolism*
  • Thymus Neoplasms / enzymology
  • Tumor Suppressor Proteins / genetics

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Reactive Oxygen Species
  • Tumor Suppressor Proteins
  • Catalase
  • Ataxia Telangiectasia Mutated Proteins
  • Atm protein, mouse
  • Protein-Serine-Threonine Kinases