Trabzuni D.,University College London |
Trabzuni D.,King Faisal Specialist Hospital And Research Center |
Ryten M.,University College London |
Emmett W.,University College London |
And 32 more authors.
PLoS ONE | Year: 2013
Association studies have identified several signals at the LRRK2 locus for Parkinson's disease (PD), Crohn's disease (CD) and leprosy. However, little is known about the molecular mechanisms mediating these effects. To further characterize this locus, we fine-mapped the risk association in 5,802 PD and 5,556 controls using a dense genotyping array (ImmunoChip). Using samples from 134 post-mortem control adult human brains (UK Human Brain Expression Consortium), where up to ten brain regions were available per individual, we studied the regional variation, splicing and regulation of LRRK2. We found convincing evidence for a common variant PD association located outside of the LRRK2 protein coding region (rs117762348, A>G, P = 2.56×10-8, case/control MAF 0.083/0.074, odds ratio 0.86 for the minor allele with 95% confidence interval [0.80-0.91]). We show that mRNA expression levels are highest in cortical regions and lowest in cerebellum. We find an exon quantitative trait locus (QTL) in brain samples that localizes to exons 32-33 and investigate the molecular basis of this eQTL using RNA-Seq data in n = 8 brain samples. The genotype underlying this eQTL is in strong linkage disequilibrium with the CD associated non-synonymous SNP rs3761863 (M2397T). We found two additional QTLs in liver and monocyte samples but none of these explained the common variant PD association at rs117762348. Our results characterize the LRRK2 locus, and highlight the importance and difficulties of fine-mapping and integration of multiple datasets to delineate pathogenic variants and thus develop an understanding of disease mechanisms. © 2013 Trabzuni et al.
PubMed | Reta Lila Weston Institute of Neurological Studies, University College London and Institute of NeurologyUniversity College LondonLondon 1E 6
Type: Journal Article | Journal: Journal of cell science | Year: 2014
DOK1 regulates platelet-derived growth factor (PDGF)-BB-stimulated glioma cell motility. Mechanisms regulating tumour cell motility are essential for invasion and metastasis. We report here that PDGF-BB-mediated glioma cell invasion and migration are dependent on the adaptor protein downstream of kinase 1 (DOK1). DOK1 is expressed in several glioma cell lines and in tumour biopsies from high-grade gliomas. DOK1 becomes tyrosine phosphorylated upon PDGF-BB stimulation of human glioma cells. Knockdown of DOK1 or expression of a DOK1 mutant (DOK1FF) containing Phe in place of Tyr at residues 362 and 398, resulted in inhibition of both the PDGF-BB-induced tyrosine phosphorylation of p130Cas (also known as BCAR1) and the activation of Rap1. DOK1 colocalises with tyrosine phosphorylated p130Cas at the cell membrane of PDGF-BB-treated cells. Expression of a non-tyrosine-phosphorylatable substrate domain mutant of p130Cas (p130Cas15F) inhibited PDGF-BB-mediated Rap1 activation. Knockdown of DOK1 and Rap1 inhibited PDGF-BB-induced chemotactic cell migration, and knockdown of DOK1 and Rap1 and expression of DOK1FF inhibited PDGF-mediated three-dimensional (3D) spheroid invasion. These data show a crucial role for DOK1 in the regulation of PDGF-BB-mediated tumour cell motility through a p130Cas-Rap1 signalling pathway. [Corrected]
Selikhova M.,University College London |
Selikhova M.,Reta Lila Weston Institute of Neurological Studies |
Tripoliti E.,University College London |
Fedoryshyn L.,Lviv Regional Clinical Hospital |
And 6 more authors.
Clinical Neurology and Neurosurgery | Year: 2016
Introduction In the last fifteen years a new cause of chronic manganese toxicity has been recognized. It follows recreational intravenous injections of Ephedrone, synthesized from a cold remedies contained pseudoephedrine. Potassium permanganate is used as an oxidant. It presents with severe parkinsonism-dystonia and a characteristic dysarthria. Objectives We performed a focus perceptual study of dysarthria in Ephedrone induced parkinsonism and compared the findings with the speech disorders seen in Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP). Methods A digital voice recording, perceptual speech analysis (Darley, 1975) , serial neurological assessment and Brain Magnetic Resonance (MR) imaging were performed at the Lviv regional Clinical Hospital. The results were analysed at the Institute of Neurology in London. Results Dysarthria developed after 8.5 ± 3.2 months of daily intravenous Ephedrone abuse and was an initial symptom in a third of cases. It was characterised by a robotic-flat prosody, whispering or continuous phonation, an inability to regulate pitch and volume, frozen lip articulation, a variable degree of dystonic tightness, difficulties in speech initiation and palladia, There was no nasality and swallowing was normal. In some patients speech deteriorated even after the discontinuation of Ephedrone. MR imaging, performed soon after drug cessation showed T1 signal hyperintesity in striatum and pallidum, especially in the Globus Pallidum interna. Conclusion Ephedrone induced chronic manganese toxicity can lead to a mixed hypokinetic-dystonic dysarthria with a distinct dystonic pattern. Perceptual speech analysis can be a helpful ancillary investigation in the differential diagnosis of parkinsonism, and may permit the recognition of chronic manganese toxicity. © 2016 Elsevier B.V. All rights reserved.
Doherty K.M.,Reta Lila Weston Institute of Neurological Studies |
Doherty K.M.,National Hospital for Neurology and Neurosurgery |
Davagnanam I.,National Hospital for Neurology and Neurosurgery |
Molloy S.,Royal National Orthopaedic Hospital |
And 5 more authors.
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2013
Background: Although Pisa syndrome and scoliosis are sometimes used interchangeably to describe a laterally flexed postural deviation in Parkinson's disease (PD), the imaging findings of Pisa syndrome in PD have not been previously studied in detail. Methods: Patients with PD and Pisa syndrome (lateral flexion >10° in the standing position) were examined clinically and underwent radiological assessment using standing radiograph and supine CT scan of the whole spine. Results: Fifteen patients were included in this observational study. All patients had scoliosis on standing radiographs, and 12 had scoliosis persisting in the supine position. Scoliotic curves improved by a mean of 44% when patients moved from standing to supine. Only a quarter of patients with structural scoliosis had evidence of bony fusion on the side of their lateral deviation rendering their deformity fixed. Conclusions: Pisa syndrome describes a patient who lists to the side whereas scoliosis is defined by spinal curvature and rotation and may not be associated with lateral flexion. The finding of 'structural scoliosis' in Pisa syndrome should not preclude intervening to improve posture as most patients had little or no evidence of structural bony changes even when the deformity had been present for a number of years.
PubMed | Reta Lila Weston Institute of Neurological Studies
Type: | Journal: Neurobiology of disease | Year: 2013
Mutations in LRRK2 are the most common genetic cause of Parkinsons disease (PD). The most prevalent LRRK2 mutation is the G2019S coding change, located in the kinase domain of this complex multi-domain protein. The majority of G2019S autopsy cases feature typical Lewy Body pathology with a clinical phenotype almost indistinguishable from idiopathic PD (iPD). Here we have investigated the biochemical characteristics of -synuclein in G2019S LRRK2 PD post-mortem material, in comparison to pathology-matched iPD. Immunohistochemistry with pS129 -synuclein antibody showed that the medulla is heavily affected with pathology in G2019S PD whilst the basal ganglia (BG), limbic and frontal cortical regions demonstrated comparable pathology scores between G2019S PD and iPD. Significantly lower levels of the highly aggregated -synuclein species in urea-SDS fractions were observed in G2019S cases compared to iPD in the BG and limbic cortex. Our data, albeit from a small number of cases, highlight a difference in the biochemical properties of aggregated -synuclein in G2019S linked PD compared to iPD, despite a similar histopathological presentation. This divergence in solubility is most notable in the basal ganglia, a region that is affected preclinically and is damaged before overt dopaminergic cell death.