Diverse mechanisms lead to common dysfunction of striatal cholinergic interneurons in distinct genetic mouse models of Dystonia

Academic Article

Abstract

  • Clinical and experimental data indicate striatal cholinergic dysfunction in dystonia, a movement disorder typically resulting in twisted postures via abnormal muscle contraction. Three forms of isolated human dystonia result from mutations in the TOR1A(DYT1), THAP1 (DYT6), and GNAL (DYT25) genes. Experimental models carrying these mutations facilitate identification of possible shared cellular mechanisms. Recently, we reported elevated extracellular striatal acetylcholine by in vivo microdialysis and paradoxical excitation of cholinergic interneurons (ChIs) by dopamine D2 receptor (D2R) agonism using ex vivo slice electrophysiology in Dyt1Δ GAG/+ mice. The paradoxical excitation was caused by overactive muscarinic receptors (mAChRs), leading to a switch in D2R coupling from canonical Gi/o to noncanonical β-arrestin signaling. We sought to determine whether these mechanisms in Dyt1Δ GAG/+ mice are shared with Thap1C54Y/+ knock-in and Gnal+/+ knock-out dystonia models and to determine the impact of sex. We found Thap1C54Y/+ mice of both sexes have elevated extracellular striatal acetylcholine and D2R-induced paradoxical ChI excitation, which was reversed by mAChR inhibition. Elevated extracellular acetylcholine was absent in male and female Gnal+/+ mice, but the paradoxical D2R-mediated ChI excitation was retained and only reversed by inhibition of adenosine A2ARs. The Gi/o-preferring D2R agonist failed to increase ChI excitability, suggesting a possible switch in coupling of D2Rs to β-arrestin, as seen previously in a DYT1 model. These data show that, whereas elevated extracellular acetylcholine levels are not always detected across these genetic models of human dystonia, the D2Rmediated paradoxical excitation of ChIs is shared and is caused by altered function of distinct G-protein-coupled receptors.
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    Digital Object Identifier (doi)

    Author List

  • Eskow Jaunarajs KL; Scarduzio M; Ehrlich ME; McMahon LL; Standaert DG
  • Start Page

  • 7195
  • End Page

  • 7205
  • Volume

  • 39
  • Issue

  • 36