Metallothionein 1 Overexpression Does Not Protect Against Mitochondrial Disease Pathology in Ndufs4 Knockout Mice

Mol Neurobiol. 2021 Jan;58(1):243-262. doi: 10.1007/s12035-020-02121-y. Epub 2020 Sep 11.

Abstract

Mitochondrial diseases (MD), such as Leigh syndrome (LS), present with severe neurological and muscular phenotypes in patients, but have no known cure and limited treatment options. Based on their neuroprotective effects against other neurodegenerative diseases in vivo and their positive impact as an antioxidant against complex I deficiency in vitro, we investigated the potential protective effect of metallothioneins (MTs) in an Ndufs4 knockout mouse model (with a very similar phenotype to LS) crossed with an Mt1 overexpressing mouse model (TgMt1). Despite subtle reductions in the expression of neuroinflammatory markers GFAP and IBA1 in the vestibular nucleus and hippocampus, we found no improvement in survival, growth, locomotor activity, balance, or motor coordination in the Mt1 overexpressing Ndufs4-/- mice. Furthermore, at a cellular level, no differences were detected in the metabolomics profile or gene expression of selected one-carbon metabolism and oxidative stress genes, performed in the brain and quadriceps, nor in the ROS levels of macrophages derived from these mice. Considering these outcomes, we conclude that MT1, in general, does not protect against the impaired motor activity or improve survival in these complex I-deficient mice. The unexpected absence of increased oxidative stress and metabolic redox imbalance in this MD model may explain these observations. However, tissue-specific observations such as the mildly reduced inflammation in the hippocampus and vestibular nucleus, as well as differential MT1 expression in these tissues, may yet reveal a tissue- or cell-specific role for MTs in these mice.

Keywords: Leigh syndrome; Metallothionein; Mitochondrial disease; Ndufs4 knockout mice; Oxidative stress; Phenotyping.

MeSH terms

  • Animals
  • Ataxia / complications
  • Ataxia / pathology
  • Ataxia / physiopathology
  • Biomarkers / metabolism
  • Body Weight
  • Disease Models, Animal
  • Electron Transport Complex I / deficiency*
  • Electron Transport Complex I / metabolism
  • Female
  • Hippocampus / pathology
  • Inflammation / blood
  • Inflammation / pathology
  • Male
  • Metabolome
  • Metallothionein / genetics
  • Metallothionein / metabolism*
  • Mice
  • Mice, Knockout
  • Mitochondrial Diseases / genetics
  • Mitochondrial Diseases / pathology*
  • Mitochondrial Diseases / physiopathology
  • Mitochondrial Diseases / prevention & control*
  • Motor Activity
  • Oxidation-Reduction
  • Oxidative Stress
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species / metabolism
  • Survival Analysis
  • beta 2-Microglobulin / metabolism

Substances

  • Biomarkers
  • Ndufs4 protein, mouse
  • RNA, Messenger
  • Reactive Oxygen Species
  • beta 2-Microglobulin
  • Metallothionein
  • Electron Transport Complex I