Abnormalities in the tricarboxylic Acid cycle in Huntington disease and in a Huntington disease mouse model

J Neuropathol Exp Neurol. 2015 Jun;74(6):527-37. doi: 10.1097/NEN.0000000000000197.


Glucose metabolism is reduced in the brains of patients with Huntington disease (HD). The mechanisms underlying this deficit, its link to the pathology of the disease, and the vulnerability of the striatum in HD remain unknown. Abnormalities in some of the key mitochondrial enzymes involved in glucose metabolism, including the pyruvate dehydrogenase complex (PDHC) and the tricarboxylic acid (TCA) cycle, may contribute to these deficits. Here, activities for these enzymes and select protein levels were measured in human postmortem cortex and in striatum and cortex of an HD mouse model (Q175); mRNA levels encoding for these enzymes were also measured in the Q175 mouse cortex. The activities of PDHC and nearly all of the TCA cycle enzymes were dramatically lower (-50% to 90%) in humans than in mice. The activity of succinate dehydrogenase increased with HD in human (35%) and mouse (23%) cortex. No other changes were detected in the human HD cortex or mouse striatum. In Q175 cortex, there were increased activities of PDHC (+12%) and aconitase (+32%). Increased mRNA levels for succinyl thiokinase (+88%) and isocitrate dehydrogenase (+64%) suggested an upregulation of the TCA cycle. These patterns of change differ from those reported in other diseases, which may offer unique metabolic therapeutic opportunities for HD patients.

Publication types

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

MeSH terms

  • Acyltransferases / genetics
  • Acyltransferases / metabolism
  • Aged
  • Aged, 80 and over
  • Animals
  • Cerebral Cortex / enzymology*
  • Citric Acid Cycle / physiology*
  • Corpus Striatum / enzymology*
  • Dihydrolipoamide Dehydrogenase / genetics
  • Dihydrolipoamide Dehydrogenase / metabolism
  • Disease Models, Animal
  • Female
  • Humans
  • Huntington Disease* / enzymology
  • Huntington Disease* / pathology
  • Huntington Disease* / physiopathology
  • Ketoglutarate Dehydrogenase Complex / genetics
  • Ketoglutarate Dehydrogenase Complex / metabolism*
  • Male
  • Mice
  • Mice, Transgenic
  • Middle Aged
  • Mutation / genetics
  • Postmortem Changes
  • Pyruvate Dehydrogenase Complex / genetics
  • Pyruvate Dehydrogenase Complex / metabolism
  • Retrospective Studies


  • Pyruvate Dehydrogenase Complex
  • Ketoglutarate Dehydrogenase Complex
  • Dihydrolipoamide Dehydrogenase
  • Acyltransferases
  • dihydrolipoamide succinyltransferase