scholarly journals Dementia risk in Parkinson’s disease is associated with interhemispheric connectivity loss and determined by regional gene expression

2020 ◽  
Vol 28 ◽  
pp. 102470
Author(s):  
Angeliki Zarkali ◽  
Peter McColgan ◽  
Mina Ryten ◽  
Regina H. Reynolds ◽  
Louise-Ann Leyland ◽  
...  
Brain ◽  
2020 ◽  
Vol 143 (11) ◽  
pp. 3435-3448
Author(s):  
Angeliki Zarkali ◽  
Peter McColgan ◽  
Mina Ryten ◽  
Regina Reynolds ◽  
Louise-Ann Leyland ◽  
...  

Abstract Visual hallucinations are common in Parkinson’s disease and are associated with poorer prognosis. Imaging studies show white matter loss and functional connectivity changes with Parkinson’s visual hallucinations, but the biological factors underlying selective vulnerability of affected parts of the brain network are unknown. Recent models for Parkinson’s disease hallucinations suggest they arise due to a shift in the relative effects of different networks. Understanding how structural connectivity affects the interplay between networks will provide important mechanistic insights. To address this, we investigated the structural connectivity changes that accompany visual hallucinations in Parkinson’s disease and the organizational and gene expression characteristics of the preferentially affected areas of the network. We performed diffusion-weighted imaging in 100 patients with Parkinson’s disease (81 without hallucinations, 19 with visual hallucinations) and 34 healthy age-matched controls. We used network-based statistics to identify changes in structural connectivity in Parkinson’s disease patients with hallucinations and performed an analysis of controllability, an emerging technique that allows quantification of the influence a brain region has across the rest of the network. Using these techniques, we identified a subnetwork of reduced connectivity in Parkinson’s disease hallucinations. We then used the Allen Institute for Brain Sciences human transcriptome atlas to identify regional gene expression patterns associated with affected areas of the network. Within this network, Parkinson’s disease patients with hallucinations showed reduced controllability (less influence over other brain regions), than Parkinson’s disease patients without hallucinations and controls. This subnetwork appears to be critical for overall brain integration, as even in controls, nodes with high controllability were more likely to be within the subnetwork. Gene expression analysis of gene modules related to the affected subnetwork revealed that down-weighted genes were most significantly enriched in genes related to mRNA and chromosome metabolic processes (with enrichment in oligodendrocytes) and upweighted genes to protein localization (with enrichment in neuronal cells). Our findings provide insights into how hallucinations are generated, with breakdown of a key structural subnetwork that exerts control across distributed brain regions. Expression of genes related to mRNA metabolism and membrane localization may be implicated, providing potential therapeutic targets.


2018 ◽  
Vol 12 (5) ◽  
pp. 410-418
Author(s):  
A. K. Emelyanov ◽  
A. O. Lavrinova ◽  
E. M. Litusova ◽  
N. A. Knyazev ◽  
D. G. Kulabukhova ◽  
...  

1995 ◽  
Vol 187 (3) ◽  
pp. 173-176 ◽  
Author(s):  
Hannsjörg Schröder ◽  
Robert A.I. de Vos ◽  
Ernst N.H. Jansen ◽  
Christina Birtsch ◽  
Andrea Wevers ◽  
...  

2015 ◽  
Author(s):  
André Valente ◽  
Altynay Adilbayeva ◽  
Tursonjan Tokay ◽  
Albert Rizvanov

Various recent developments of relevance to Parkinson's disease (PD) are discussed and integrated into a comprehensive hypothesis on the nature, origin and inter-cellular mode of propagation of late-onset sporadic PD. We propose to define sporadic PD as a characteristic pathological deviation in the global gene expression program of a cell: the PD expression-state, or PD-state for short. Although a universal cell-generic state, the PD-state deviation would be particularly damaging in a neuronal context, ultimately leading to neuron death and the ensuing observed clinical signs. We review why age accumulated damage caused by oxidative stress in mitochondria could be the trigger for a primordial cell to shift to the PD-state. We put forward hematopoietic cells could be the first to acquire the PD-state, at hematopoiesis, from the disruption in reactive oxygen species (ROS) homeostasis that arises with age in the hematopoietic stem-cell niche. We argue why, nonetheless, such a process is unlikely to explain the shift to the PD-state of all the subsequently affected cells in a patient, thus indicating the existence of a distinct mechanism of propagation of the PD-state. We highlight recent findings on the intercellular exchange of mitochondrial DNA and the ability of mitochondrial DNA to modulate the cellular global gene expression state and propose this could form the basis for the intercellular propagation of the PD-state.


2017 ◽  
Author(s):  
Jeremy Schwartzentruber ◽  
Stefanie Foskolou ◽  
Helena Kilpinen ◽  
Julia Rodrigues ◽  
Kaur Alasoo ◽  
...  

AbstractInduced pluripotent stem cells (iPSCs), and cells derived from them, have become key tools to model biological processes and disease mechanisms, particularly in cell types such as neurons that are difficult to access from living donors. Here, we present the first map of regulatory variants in an iPSC-derived cell type. To investigate genetic contributions to human sensory function, we performed 123 differentiations of iPSCs from 103 unique donors to a sensory neuronal fate, and measured gene expression, chromatin accessibility, and neuronal excitability. Compared with primary dorsal root ganglion, where sensory nerves collect near the spinal cord, gene expression was more variable across iPSC-derived neuronal cultures, particularly in genes related to differentiation and nervous system development. Single cell RNA-sequencing revealed that although the majority of cells are neuronal and express the expected marker genes, a substantial fraction have a fibroblast-like expression profile. By applying an allele-specific method we identify 3,778 quantitative trait loci influencing gene expression, 6,318 for chromatin accessibility, and 2,097 for RNA splicing at FDR 10%. A number of these overlap with common disease associations, and suggest candidate causal variants and target genes. These include known causal variants at SNCA for Parkinson’s disease and TNFRSF1A for multiple sclerosis, as well as new candidates for migraine, Parkinson’s disease, and schizophrenia.


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