Age-Related Oxidative Changes in Primary Porcine Fibroblasts Expressing Mutated Huntingtin

Neurodegener Dis. 2019;19(1):22-34. doi: 10.1159/000500091. Epub 2019 Jun 5.

Abstract

Background: Huntington's disease (HD) is a devastating neurodegenerative disorder caused by CAG triplet expansions in the huntingtin gene. Oxidative stress is linked to HD pathology, although it is not clear whether this is an effect or a mediator of disease. The transgenic (TgHD) minipig expresses the N-terminal part of human-mutated huntingtin and represents a unique model to investigate therapeutic strategies towards HD. A more detailed characterization of this model is needed to fully utilize its potential.

Methods: In this study, we focused on the molecular and cellular features of fibroblasts isolated from TgHD minipigs and the wild-type (WT) siblings at different ages, pre-symptomatic at the age of 24-36 months and with the onset of behavioural symptoms at the age of 48 months. We measured oxidative stress, the expression of oxidative stress-related genes, proliferation capacity along with the expression of cyclin B1 and D1 proteins, cellular permeability, and the integrity of the nuclear DNA (nDNA) and mitochondrial DNA in these cells.

Results: TgHD fibroblasts isolated from 48-month-old animals showed increased oxidative stress, which correlated with the overexpression of SOD2 encoding mitochondrial superoxide dismutase 2, and the NEIL3 gene encoding DNA glycosylase involved in replication-associated repair of oxidized DNA. TgHD cells displayed an abnormal proliferation capacity and permeability. We further demonstrated increased nDNA damage in pre-symptomatic TgHD fibroblasts (isolated from animals aged 24-36 months).

Conclusions: Our results unravel phenotypic alterations in primary fibroblasts isolated from the TgHD minipig model at the age of 48 months. Importantly, nDNA damage appears to precede these phenotypic alterations. Our results highlight the impact of fibroblasts from TgHD minipigs in studying the molecular mechanisms of HD pathophysiology that gradually occur with age.

Keywords: Permeability; DNA damage; Huntington’s disease; Large-animal model; Minipig model; Mutated huntingtin; Oxidative stress; Primary fibroblasts; Proliferation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Animals
  • Animals, Genetically Modified
  • Cell Division
  • DNA Damage
  • DNA, Mitochondrial / genetics
  • Fibroblasts / metabolism*
  • Gene Expression Regulation
  • Humans
  • Huntingtin Protein / genetics
  • Huntingtin Protein / metabolism*
  • Lipid Peroxidation
  • N-Glycosyl Hydrolases / biosynthesis
  • N-Glycosyl Hydrolases / genetics
  • Oxidative Stress
  • Phenotype
  • Primary Cell Culture
  • Reactive Oxygen Species / metabolism
  • Superoxide Dismutase / biosynthesis
  • Superoxide Dismutase / genetics
  • Swine
  • Swine, Miniature

Substances

  • DNA, Mitochondrial
  • HTT protein, human
  • Huntingtin Protein
  • Reactive Oxygen Species
  • Superoxide Dismutase
  • superoxide dismutase 2
  • N-Glycosyl Hydrolases