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. 2009 Feb;2(1):50-9.
doi: 10.1002/aur.62.

Decreased GAD65 mRNA levels in select subpopulations of neurons in the cerebellar dentate nuclei in autism: an in situ hybridization study

Jane Yip  1 , Jean Jacques Soghomonian, Gene J Blatt
Affiliations

Decreased GAD65 mRNA levels in select subpopulations of neurons in the cerebellar dentate nuclei in autism: an in situ hybridization study

Jane Yip et al. Autism Res. 2009 Feb.

Abstract

The laterally positioned dentate nuclei lie in a key position in the cerebellum to receive input from Purkinje cells in the lateral cerebellar hemisphere participating in both motor and cognitive functions. Although neuropathology of the four cerebellar nuclei using Nissl staining has been qualitatively reported in children and adults with autism, surprisingly the dentate nuclei appeared less affected despite reported reductions in Purkinje cells in the posterolateral cerebellar hemisphere. To determine any underlying abnormalities in the critically important GABAergic system, the rate-limiting GABA synthesizing enzyme, glutamic acid decarboxylase (GAD) type 65 was measured via in situ hybridization histochemistry in dentate somata. GAD65 mRNA labeling revealed two distinct subpopulations of neurons in adult control and autism postmortem brains: small-sized cells (about 10-12 microm in diameter, presumed interneurons) and larger-sized neurons (about 18-20 microm in diameter, likely feedback to inferior olivary neurons). A mean 51% reduction in GAD65 mRNA levels was found in the larger labeled cells in the autistic group compared with the control group (P=0.009; independent t-test) but not in the smaller cell subpopulation. This suggests a disturbance in the intrinsic cerebellar circuitry in the autism group potentially interfering with the synchronous firing of inferior olivary neurons, and the timing of Purkinje cell firing and inputs to the dentate nuclei. Disturbances in critical neural substrates within these key circuits could disrupt afferents to motor and/or cognitive cerebral association areas in the autistic brain likely contributing to the marked behavioral consequences characteristic of autism.

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Figures

Figure 1
Figure 1
Histograms showing the relative distribution of cell profiles (measured length across cell through nucleolus in mm) sampled from dentate neurons from control subjects (60 neurons from each of five cases for the H&E stain and 40 neurons for the Nissl stain). The neurons were estimated from photomicrographs captured from a light microscope (Zeiss axioskop 40) precalibrated for length measurements. A) H&E stained sections processed for in situ hybridization demonstrate two large peaks at 10 µm and 20 µm and a few lower peaks including one at 15 µm. B) Nissl-stained adjacent sections. Note that the distribution, based on neuronal profiles, are very similar in the two methods.
Figure 2
Figure 2
Examples of Nissl-stained sections that were taken from an adjacent series to the in situ hybridization series from a control case illustrating dentate neurons of varying sizes. The photomicrographs show cell profiles (length across nucleolus in µm) in A) approximately 10 µm and 20 µm (arrows) respectively. In this study, these small and larger- sized cells were most abundant in both controls and autistic cases. The largest identified cell is shown in B (approximately 30 µm; arrow) and depicts the ranges of dentate neuronal sizes. Note that measurements were rounded such that a 10 µm cell profile represents measurements ranging from 9.50 to 10.49. Scale bar = 10 µm refers to both panels A and B.
Figure 3
Figure 3
Film radioautogram showing GAD65 mRNA-labeled control cerebellum. The black arrows indicate dentate nuclei. The open arrows show GAD65 mRNA-labeled Purkinje cells.
Figure 4
Figure 4
GAD65 mRNA-labeled neurons (arrows) in the dentate nuclei in a control case of a small cell in A) and a larger cell in B). Note the silver grain GAD65-mRNA-positive labeling throughout both cells. Scale bar in = 20 µm and refers to both A and B.
Figure 5
Figure 5
Scatter plot showing the mean levels of GAD65 in the dentate nuclei in five autistic and five control subjects for small 10 µm cells (A) and larger-sized 20 µm cells. Statistical analysis of the larger cell subpopulation showed a significant reduction in GAD65 mRNA levels in the dentate nuclei in the autistic group compared to age-, PMI and pH-matched controls (P** 0.03, independent t-test).
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References

    1. Akbarian S, Huang HS. Molecular and cellular mechanisms of altered GAD1/GAD67 expression in schizophrenia and related disorders. Brain Res Rev. 2006;52(2):293–304. - PubMed
    1. American Psychiatric Association, Diagnostic and statistical manual of mental disorders. 4th ed. Washington, DC: American Psychiatric Association; 1994.
    1. Arin DM, Bauman ML, Kemper TL. The distribution of Purkinje cell loss in the cerebellum in autism. Neurology. 1991;41 Suppl:307.
    1. Bailey A, Luthert P, Dean A, Harding B, Janota I, Montgomery M, Rutter M, Lantos P. A Clinicopathological study of autism. Brain. 1998;121:889–905. - PubMed
    1. Barton AJL, Pearson RCA, Najlerahim A, Harrison PJ. Pre-and postmortem influences on brain RNA. J Neurochemistry. 1993;61(1):1–11. - PubMed

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