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Mitochondrial Isolation from Skeletal Muscle
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Huntingtin Aggregates and Mitochondrial Pathology in Skeletal Muscle but not Heart of Late-Stage R6/2 Mice

Kerstin Kojer1, Tanja Hering1, Chantal Bazenet2

  • 1Department of Neurology, Ulm University, Ulm, Germany.

Journal of Huntington'S Disease
|March 1, 2019
PubMed
Abstract

Insights

Huntington's disease (HD) mutation aggregates form in skeletal muscle but not heart, leading to mitochondrial dysfunction in muscle. Heart tissue appears protected from HD pathology.

Area of Science:

  • Neurodegenerative Diseases
  • Molecular Biology
  • Mitochondrial Biology

Background:

  • Cellular context influences Huntington's disease (HD) mutation effects.
  • Aggregate formation occurs in skeletal muscle but not heart in the R6/2 HD mouse model.

Purpose of the Study:

  • To investigate the association between huntingtin aggregate formation, expression, and subcellular localization with mitochondrial dysfunction.
  • To analyze mitochondrial health in relation to huntingtin species in different tissues.

Main Methods:

  • Analysis of soluble huntingtin (HTT) and HTT aggregates in quadriceps and heart of R6/2 mice.
  • Measurement of fission/fusion proteins (DRP1, MFN2) and mitochondrial respiratory chain activities.
  • Fractionation of tissues to determine subcellular localization of huntingtin species.

Main Results:

  • Soluble mutant HTT was found in both tissues, with higher expression in cytoplasmic/mitochondrial fractions.
  • HTT aggregates were detected only in R6/2 quadriceps, linked to altered DRP1 and MFN2 levels and decreased respiratory chain activities.
  • No mitochondrial dysfunction was observed in heart tissue lacking detectable HTT aggregates.

Conclusions:

  • Tissue-specific factors may protect the R6/2 mouse heart from huntingtin aggregate formation and mitochondrial pathology.
  • Skeletal muscle in the R6/2 model exhibits significant mitochondrial dysfunction associated with HTT aggregation.
Keywords:
Huntingtinfission and fusionmitochondriarespiratory chainskeletal muscle

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