We have a PhD studentship available that is focused on uncovering the imaging and genetic basis of drug-resistant epilepsy. More details are available here.
Marzia’s paper with the title “Genetic study of multimodal imaging Alzheimer’s disease progression score implicates novel loci” has been published in Brain. Congrats!
Identifying genetic risk factors underpinning different aspects of Alzheimer’s disease has the potential to provide important insights into pathogenesis. Moving away from simple case-control definitions, there is considerable interest in using quantitative endophenotypes, such as those derived from imaging as outcome measures. Previous genome-wide association studies of imaging-derived biomarkers in sporadic late-onset Alzheimer’s disease focused only on phenotypes derived from single imaging modalities. In contrast, we computed a novel multi-modal neuroimaging phenotype comprising cortical amyloid burden and bilateral hippocampal volume. Both imaging biomarkers were used as input to a disease progression modelling algorithm, which estimates the biomarkers’ long-term evolution curves from population-based longitudinal data. Among other parameters, the algorithm computes the shift in time required to optimally align a subjects’ biomarker trajectories with these population curves. This time shift serves as a disease progression score and it was used as a quantitative trait in a discovery genome-wide association study with n = 944 subjects from the Alzheimer’s Disease Neuroimaging Initiative database diagnosed as Alzheimer’s disease, mild cognitive impairment or healthy at the time of imaging. We identified a genome-wide significant locus implicating LCORL (rs6850306, chromosome 4; P = 1.03 × 10−8). The top variant rs6850306 was found to act as an expression quantitative trait locus for LCORL in brain tissue. The clinical role of rs6850306 in conversion from healthy ageing to mild cognitive impairment or Alzheimer’s disease was further validated in an independent cohort comprising healthy, older subjects from the National Alzheimer’s Coordinating Center database. Specifically, possession of a minor allele at rs6850306 was protective against conversion from mild cognitive impairment to Alzheimer’s disease in the National Alzheimer’s Coordinating Center cohort (hazard ratio = 0.593, 95% confidence interval = 0.387–0.907, n = 911, PBonf = 0.032), in keeping with the negative direction of effect reported in the genome-wide association study (βdisease progression score = −0.07 ± 0.01). The implicated locus is linked to genes with known connections to Alzheimer’s disease pathophysiology and other neurodegenerative diseases. Using multimodal imaging phenotypes in association studies may assist in unveiling the genetic drivers of the onset and progression of complex diseases.
Our paper with the “Genetic study of multimodal imaging Alzheimer’s disease progression score implicates novel loci” was accepted for publication in Brain!
Authors: Marzia A. Scelsi, Raiyan R. Khan, Marco Lorenzi, Leigh Christopher , Michael D. Greicius, Jonathan M. Schott, Sebastien Ourselin, Andre Altmann
A Related abstract at OHBM 2017 can be found here.
Our paper with the title “Predicting outcome in idiopathic pulmonary fibrosis using automated CT analysis” was accepted in AJRCCM!
Joseph Jacob, Brian J. Bartholmai, Srinivasan Rajagopalan, Coline H.M. van Moorsel, Hendrik W. van Es, Frouke T. van Beek, Marjolijn H.L. Struik, Maria Kokosi, Ryoko Egashira, Anne Laure Brun, Arjun Nair, Simon L.F. Walsh, Gary Cross, Joseph Barnett, Angelo de Lauretis, Eoin P. Judge, Sujal, Desai, Ronald Karwoski, Sebastien Ourselin, Elisabetta Renzoni, Toby M. Maher, Andre Altmann, Athol U. Wells
Our abstract “Rare genetic events in sporadic Alzheimer’s disease: a network propagation approach” was selected for an oral presentation at OHBM 2018, Singapore!
On top of that lead author Marzia Scelsi received (again!) a Merit Abstract Award for the 2018 OHBM Annual Meeting. Congrats Marzia!
M. A. Scelsi, J. E. Iglesias, J M Schott, S Ourselin, A Altmann, “Rare genetic events in sporadic Alzheimer’s disease: a network propagation approach”
The discovery of rare genetic mutations in the APP, PSEN1, and PSEN2 that cause familial Alzheimer’s disease (AD) has had profound implications for our understanding of deisease pathognesis. There is much interest in investigating rare genetic variants that might increase risk for, or influence the phenotype of, sporadic AD. This however remains challenging due to the very large sample sizes required and the costs of performing whole-genome sequencing (WGS) in these cohorts. Early successes have included the discovery that TREM2 influences risk (Guerreiro et al. 2013), a discovery that has intensified interest in inflammation in AD. Studies such as the Alzheimer’s Disease Sequencing Project (Bis et al. 2017) continue to address this challenge. Here, we present a method to investigate the effects of rare variant in moderately sized sporadic AD cohorts, such as ADNI Our approach is based on signal diffusion on a gene-interaction network, inspired by its successful application to cancer subtyping (Hofree et al. 2013). We sought to develop an integrative approach to guide gene-based association testing with the knowledge of tissue-specific interaction networks.
Our paper with the title “Susceptibility of brain atrophy to TRIB3 in Alzheimer’s disease, evidence from functional prioritization in imaging genetics” is now available online at PNAS!
Read the TIG news story here!
In this study, we use an experimental imaging–genetics approach for investigating the genetic underpinnings of brain atrophy in Alzheimer’s disease. We successfully combined state-of-the-art imaging–genetics methods and experimental gene expression data to uncover biology in brain atrophy. The experimental paradigm highlighted a significant role of tribbles pseudokinase 3 (TRIB3) in modulating the typical pattern of Alzheimer’s brain pathology. This result corroborates through rigorous data-driven statistical methods evidence emerging from previous studies about the role of TRIB3 in modulating known mechanisms of neurodegeneration, such as neuronal death, cellular homeostasis, and interaction with established genes causing autosomal dominant Alzheimer’s disease: APP and PSEN1. The developed integrated statistical–experimental methodology could serve as a roadmap for investigations in other disorders.
See also UCL’s press release here.
Whelan et al., 2018: “Structural brain abnormalities in the common epilepsies assessed in a worldwide ENIGMA study”
Marzia was interviewed about her newsworthy OHBM 2017 contribution!! Click here to read the interview!
Our paper with the title “Overdominant effect of a CHRNA4 polymorphism on cingulo-opercular network activity and cognitive control” is now available online at the Journal of Neuroscience.
The nicotinic system plays an important role in cognitive control, and is implicated in several neuropsychiatric conditions. Yet, the contributions of genetic variability in this system to individuals’ cognitive control abilities are poorly understood, and the brain processes that mediate such genetic contributions remain largely unidentified. In this first large-scale neuroimaging genetics study of the human nicotinic receptor system (two cohorts, males and females, fMRI total N=1586, behavioral total N=3650), we investigated a common polymorphism of the high-affinity nicotinic receptor α4β2 (rs1044396 on the CHRNA4 gene) previously implicated in behavioral and nicotine-related studies (albeit with inconsistent major/minor allele impacts). Based on our prior neuroimaging findings, we expected this polymorphism to impact neural activity in the cingulo-opercular network involved in core cognitive control processes including maintenance of alertness. Consistent across the cohorts, all cortical areas of the cingulo-opercular network showed higher activity in heterozygotes compared to both types of homozygotes during cognitive engagement. This inverted U-shaped relation reflects an overdominant effect, i.e. allelic interaction (cumulative evidence p=1.33*10-5). Furthermore, heterozygotes performed more accurately in behavioral tasks that primarily depend on sustained alertness. No effects were observed for haplotypes of the surrounding CHRNA4 region, supporting a true overdominant effect at rs1044396. As a possible mechanism, we observed that this polymorphism is an expression quantitative trait locus (eQTL) modulating CHRNA4 expression levels. This is the first report of overdominance in the nicotinic system. These findings connect CHRNA4 genotype, cingulo-opercular network activation and sustained alertness, providing insights into how genetics shapes individuals’ cognitive control abilities.
The nicotinic acetylcholine system plays a central role in neuromodulatory regulation of cognitive control processes, and is dysregulated in several neuropsychiatric disorders. In spite of this functional importance, no large-scale neuroimaging genetics studies have targeted the contributions of genetic variability in this system to human brain activity. Here, we show impact of a common polymorphism of the high-affinity nicotinic receptor α4β2, consistent across brain activity and behavior in two large human cohorts. We report a hitherto unknown overdominant effect (allelic interaction) at this locus, where the heterozygotes show higher activity in the cingulo-opercular network underlying alertness maintenance, and higher behavioral alertness performance than both homozygous groups. This gene-brain-behavior relationship informs about the biological basis of inter-individual differences in cognitive control.
Our paper with the title “Overdominant effect of a CHRNA4 polymorphism on cingulo-opercular network activity and cognitive control” was accepted for publication in the Journal of Neuroscience.
Authors: Sepideh Sadaghiani, Bernard Ng, Andre Altmann, Jean-Baptiste Poline, Tobias Banaschewski, Arun Bokde, Uli Bromberg, Christian Büchel, Erin Burke Quinlan, Patricia Conrod, Sylvane Desrivières, Herta Flor, Vincent Frouin, Hugh Garavan, Penny Gowland, Juergen Gallinat, Andreas Heinz, Bernd Ittermann, Jean-Luc Martinot, Marie-Laure Martinot, Hervé Lemaitre, Frauke Nees, Dimitri Papadopoulos Orfanos, Tomas Paus, Luise Poustka, Sabina Millenet, Juliane Fröhner, Michael Smolka, Henrik Walter, Robert Whelan, Gunter Schumann, Valerio Napolioni, Michael Greicius