Article

Altered dendritic morphology of Purkinje cells in Dyt1 ΔGAG knock-in and purkinje cell-specific Dyt1 conditional knockout mice.

Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
PLoS ONE (Impact Factor: 3.73). 01/2011; 6(3):e18357. DOI: 10.1371/journal.pone.0018357
Source: PubMed

ABSTRACT DYT1 early-onset generalized dystonia is a neurological movement disorder characterized by involuntary muscle contractions. It is caused by a trinucleotide deletion of a GAG (ΔGAG) in the DYT1 (TOR1A) gene encoding torsinA; the mouse homolog of this gene is Dyt1 (Tor1a). Although structural and functional alterations in the cerebellum have been reported in DYT1 dystonia, neuronal morphology has not been examined in vivo.
In this study, we examined the morphology of the cerebellum in Dyt1 ΔGAG knock-in (KI) mice. Golgi staining of the cerebellum revealed a reduction in the length of primary dendrites and a decrease in the number of spines on the distal dendrites of Purkinje cells. To determine if this phenomenon was cell autonomous and mediated by a loss of torsinA function in Purkinje cells, we created a knockout of the Dyt1 gene only in Purkinje cells of mice. We found the Purkinje-cell specific Dyt1 conditional knockout (Dyt1 pKO) mice have similar alterations in Purkinje cell morphology, with shortened primary dendrites and decreased spines on the distal dendrites.
These results suggest that the torsinA is important for the proper development of the cerebellum and a loss of this function in the Purkinje cells results in an alteration in dendritic structure.

0 Bookmarks
 · 
102 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The dystonias are a group of disorders characterized by involuntary twisting and repetitive movements. DYT1 dystonia is an inherited form of dystonia caused by a mutation in the TOR1A gene, which encodes torsinA. TorsinA is expressed in many regions of the nervous system, and the regions responsible for causing dystonic movements remain uncertain. Most prior studies have focused on the basal ganglia, although there is emerging evidence for abnormalities in the cerebellum too. In the current studies, we examined the cerebellum for structural abnormalities in a knock-in mouse model of DYT1 dystonia. The gross appearance of the cerebellum appeared normal in the mutant mice, but stereological measures revealed the cerebellum to be 5% larger in mutant compared to control mice. There were no changes in the numbers of Purkinje cells, granule cells, or neurons of the deep cerebellar nuclei. However, Golgi histochemical studies revealed Purkinje cells to have thinner dendrites, and fewer and less complex dendritic spines. There also was a higher frequency of heterotopic Purkinje cells displaced into the molecular layer. These results reveal subtle structural abnormalities of the cerebellum that are similar to those reported for the basal ganglia in the DYT1 knock-in mouse model.
    Neurobiology of Disease 10/2013; · 5.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Presynaptic functions of the mammalian central neurons are regulated by a network of protein interactions. Synaptic vesicle recycling in and neurotransmitter release from the presynaptic nerve terminals are altered when a glutamate-deleting mutation is present in the torsinA protein (ΔE-torsinA). This mutation is linked with a hereditary form of the movement disorder dystonia known as DYT1 dystonia. Although torsinA expression is prevalent throughout the central nervous system, its subcellular localization - in particular with respect to presynaptic nerve terminals - remains unclear. This information would be useful in narrowing down possible models for how wild-type torsinA affects presynaptic function, as well as the nature of the presynaptic dysfunction that arises in the context of ΔE-torsinA mutation. Here we report on an analysis of the presynaptic localization of torsinA in cultured neurons obtained from a knock-in mouse model of DYT1 dystonia. Primary cultures of neurons were established from heterozygous and homozygous ΔE-torsinA knock-in mice, as well as form their wild-type littermates. Neurons were obtained from the striatum, cerebral cortex and hippocampus of these mice, and were subjected to immunocytochemistry. This analysis revealed expression of both proteins in the somata and dendrites. However, neither the nerve terminals nor axonal shafts were immunoreactive. These results were confirmed by fluorogram-based quantitation. Our findings indicate that neither the wild-type nor the ΔE-torsinA mutant protein is present at substantial levels in the presynaptic structures of cultured neurons. Thus, the effects of torsinA, in wild-type and mutant forms, appear to influence presynaptic function indirectly, without residing in presynaptic structures.
    Neuroscience 09/2013; · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Microfluidic platforms for quantitative evaluation of cell biologic processes allow low cost and time efficient research studies of biological and pathological events, such as monitoring cell migration by real-time imaging. In healthy and disease states, cell migration is crucial in development and wound healing, as well as to maintain the body's homeostasis. New Method The microfluidic chambers allow precise measurements to investigate whether fibroblasts carrying a mutation in the TOR1A gene, underlying the hereditary neurologic disease - DYT1 dystonia, have decreased migration properties when compared to control cells. Results We observed that fibroblasts from DYT1 patients showed abnormalities in basic features of cell migration, such as reduced velocity and persistence of movement. Comparison with Existing Method The microfluidic method enabled us to demonstrate reduced polarization of the nucleus and abnormal orientation of nuclei and Golgi inside the moving DYT1 patient cells compared to control cells, as well as vectorial movement of single cells. Conclusion We report here different assays useful in determining various parameters of cell migration in DYT1 patient cells as a consequence of the TOR1A gene mutation, including a microfluidic platform, which provides a means to evaluate real-time vectorial movement with single cell resolution in a three-dimensional environment.
    Journal of Neuroscience Methods. 01/2014;

Full-text (2 Sources)

View
1 Download
Available from