Catecholamine-related gene expression in blood correlates with tic severity in tourette syndrome
PSYCHIATRY RESEARCH
Authors: Gunther, Joan; Tian, Yingfang; Stamova, Boryana; Lit, Lisa; Corbett, Blythe; Ander, Brad; Zhan, Xinhua; Jickling, Glen; Bos-Veneman, Netty; Liu, Da; Hoekstra, Pieter; Sharp, Frank
Abstract
Tourette syndrome (TS) is a heritable disorder characterized by tics that are decreased in some patients by treatment with alpha adrenergic agonists and dopamine receptor blockers. Thus, this study examines the relationship between catecholamine gene expression in blood and tic severity. TS diagnosis was confirmed using Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria and tic severity measured using the Yale Global Tic Severity Scale (YGTSS) for 26 un-medicated subjects with TS. Whole blood was collected and Ribonucleic acid (RNA) processed on Affymetrix Human Exon 1.0 ST arrays. An Analysis of Covariance (ANCOVA) identified 3627 genes correlated with tic severity (p < 0.05). Searches of Medical Subject Headings, Gene Ontology, Allen Mouse Brain Atlas, and PubMed determined genes associated with catecholamines and located in the basal ganglia. Using GeneCards, PubMed, and manual curation, seven genes associated with TS were further examined: DRD2, HRH3, MAOB, BDNF, SNAP25, SLC6A4, and SLC22A3. These genes are highly associated with TS and have also been implicated in other movement disorders, Attention Deficit Hyperactivity Disorder (ADHD), and Obsessive-Compulsive Disorder (OCD). Correlation of gene expression in peripheral blood with tic severity may allow inferences about catecholamine pathway dysfunction in TS subjects. Findings built on previous work suggest that at least some genes expressed peripherally are relevant for central nervous system (CNS) pathology in the brain of individuals with TS. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
Neuronal targeting, internalization, and biological activity of a recombinant atoxic derivative of botulinum neurotoxin A
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Pellett, Sabine; Tepp, William H.; Stanker, Larry H.; Band, Philip A.; Johnson, Eric A.; Ichtchenko, Konstantin
Abstract
Non-toxic derivatives of botulinum neurotoxin A (BoNT/A) have potential use as neuron-targeting delivery vehicles, and as reagents to study intracellular trafficking. We have designed and expressed an atoxic derivative of BoNT/A (BoNT/A ad) as a full-length 150 kDa molecule consisting of a 50 kDa light chain (LC) and a 100 kDa heavy chain (HC) joined by a disulfide bond and rendered atoxic through the introduction of metalloprotease-inactivating point mutations in the light chain. Studies in neuronal cultures demonstrated that BoNT/A ad cannot cleave synaptosomal-associated protein 25 (SNAP25), the substrate of wt BoNT/A, and that it effectively competes with wt BoNT/A for binding to endogenous neuronal receptors. In vitro and in vivo studies indicate accumulation of BoNT/A ad at the neuromuscular junction of the mouse diaphragm. Immunoprecipitation studies indicate that the LC of BoNT/A ad forms a complex with SNAP25 present in the neuronal cytosolic fraction, demonstrating that the atoxic LC retains the SNAP25 binding capability of the wt toxin. Toxicity of BoNT/A ad was found to be reduced approximately 100,000-fold relative to wt BoNT/A. (C) 2011 Elsevier Inc. All rights reserved.