Browsing by Author "Schellenberg, Gerard"

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    Cerebral amyloid angiopathy impacts neurofibrillary tangle burden and cognition
    (Oxford University Press, 2024-11-22) Godrich, Dana; Pasteris, Jeremy; Martin, Eden R.; Rundek, Tatjana; Schellenberg, Gerard; Foroud, Tatiana; Vance, Jeffery M.; Pericak-Vance, Margaret A.; Cuccaro, Michael L.; Scott, William K.; Kukull, Walter; Montine, Thomas J.; Beecham, Gary W.; Medical and Molecular Genetics, School of Medicine
    Cerebral amyloid angiopathy commonly co-occurs with amyloid β plaques and neurofibrillary degeneration and is proposed to contribute to cognitive impairment. However, the interplay among these pathologic changes of Alzheimer disease is not well understood. Here we replicate and extend findings of a recent study that suggested the association of cerebral amyloid angiopathy and cognitive impairment is mediated by neurofibrillary degeneration. We employed similar approaches but in a larger, clinical-based (as opposed to community-based) set of 4915 autopsied National Alzheimer's Coordinating Center participants (60% with dementia). Neuropathologic lesions were measured ordinally; longitudinal change in cognition was used to measure cognitive impairment. Statistical analyses included ordinal logistic regression, mediation analyses and extension of models to include presence of APOE e4. We show a statistical interaction between cerebral amyloid angiopathy and neuritic plaques that impacts the burden of neurofibrillary tangles. Mediation analyses show that cerebral amyloid angiopathy is associated with cognitive impairment, but only by modifying the impact of neurofibrillary tangles on cognition. We expanded the mediation analysis to include APOE e4 and show similar results. Findings indicate that cerebral amyloid angiopathy plays an important role in the burden and impact of neurofibrillary degeneration contributing to cognitive impairment.
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    Genetic variants and functional pathways associated with resilience to Alzheimer’s disease
    (Oxford, 2020-08-25) Dumitrescu, Logan; Mahoney, Emily R; Mukherjee, Shubhabrata; Lee, Michael L; Bush, William S; Engelman, Corinne D; Lu, Qiongshi; Fardo, David W; Trittschuh, Emily H; Mez, Jesse; Kaczorowski, Catherine; Hernandez Saucedo, Hector; Widaman, Keith F; Buckley, Rachel; Properzi, Michael; Mormino, Elizabeth; Yang, Hyun-Sik; Harrison, Tessa; Hedden, Trey; Nho, Kwangsik; Andrews, Shea J; Tommet, Doug; Hadad, Niran; Sanders, R Elizabeth; Ruderfer, Douglas M; Gifford, Katherine A; Moore, Annah M; Cambronero, Francis; Zhong, Xiaoyuan; Raghavan, Neha S.; Vardarajan, Badri; Pericak-Vance, Margaret A.; Farrer, Lindsay A.; Wang, Li-San; Cruchaga, Carlos; Schellenberg, Gerard; Cox, Nancy J.; Haines, Jonathan L,; Keene, C. Dirk; Saykin, Andrew J.; Larson, Eric B.; Sperling, Reisa A.; Mayeux, Richard; Bennett, David A.; Schneider, Julie A.; Crane, Paul K.; Jefferson, Angela L.; Hohman, Timothy J.; Radiology and Imaging Sciences, School of Medicine
    Approximately 30% of older adults exhibit the neuropathological features of Alzheimer’s disease without signs of cognitive impairment. Yet, little is known about the genetic factors that allow these potentially resilient individuals to remain cognitively unimpaired in the face of substantial neuropathology. We performed a large, genome-wide association study (GWAS) of two previously validated metrics of cognitive resilience quantified using a latent variable modelling approach and representing better-than-predicted cognitive performance for a given level of neuropathology. Data were harmonized across 5108 participants from a clinical trial of Alzheimer’s disease and three longitudinal cohort studies of cognitive ageing. All analyses were run across all participants and repeated restricting the sample to individuals with unimpaired cognition to identify variants at the earliest stages of disease. As expected, all resilience metrics were genetically correlated with cognitive performance and education attainment traits (P-values < 2.5 × 10−20), and we observed novel correlations with neuropsychiatric conditions (P-values < 7.9 × 10−4). Notably, neither resilience metric was genetically correlated with clinical Alzheimer’s disease (P-values > 0.42) nor associated with APOE (P-values > 0.13). In single variant analyses, we observed a genome-wide significant locus among participants with unimpaired cognition on chromosome 18 upstream of ATP8B1 (index single nucleotide polymorphism rs2571244, minor allele frequency = 0.08, P = 2.3 × 10−8). The top variant at this locus (rs2571244) was significantly associated with methylation in prefrontal cortex tissue at multiple CpG sites, including one just upstream of ATPB81 (cg19596477; P = 2 × 10−13). Overall, this comprehensive genetic analysis of resilience implicates a putative role of vascular risk, metabolism, and mental health in protection from the cognitive consequences of neuropathology, while also providing evidence for a novel resilience gene along the bile acid metabolism pathway. Furthermore, the genetic architecture of resilience appears to be distinct from that of clinical Alzheimer’s disease, suggesting that a shift in focus to molecular contributors to resilience may identify novel pathways for therapeutic targets.
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    Genome-wide association study identifies four novel loci associated with Alzheimer's endophenotypes and disease modifiers
    (Springer Verlag, 2017-05) Deming, Yuetiva; Li, Zeran; Kapoor, Manav; Harari, Oscar; Del-Aguila, Jorge L.; Black, Kathleen; Carrell, David; Cai, Yefei; Fernandez, Maria Victoria; Budde, John; Ma, Shengmei; Saef, Benjamin; Howells, Bill; Huang, Kuanlin; Bertelsen, Sarah; Fagan, Anne M.; Holtzman, David M.; Morris, John C.; Kim, Sungeun; Saykin, Andrew J.; De Jager, Philip L.; Albert, Marilyn; Moghekar, Abhay; O’Brien, Richard; Riemenschneider, Matthias; Petersen, Ronald C.; Blennow, Kaj; Zetterberg, Henrik; Minthon, Lennart; Van Deerlin, Vivianna M.; Lee, Virginia Man-Yee; Shaw, Leslie M.; Trojanowski, John Q.; Schellenberg, Gerard; Haines, Jonathan L.; Mayeux, Richard; Pericak-Vance, Margaret A.; Farrer, Lindsay A.; Peskind, Elaine R.; Li, Ge; Di Narzo, Antonio F.; Alzheimer’s Disease Neuroimaging Initiative (ADGC). The Alzheimer Disease Genetic Consortium (ADGC); Kauwe, John S. K.; Goate, Alison M.; Cruchaga, Carlos; Medicine, School of Medicine
    More than 20 genetic loci have been associated with risk for Alzheimer's disease (AD), but reported genome-wide significant loci do not account for all the estimated heritability and provide little information about underlying biological mechanisms. Genetic studies using intermediate quantitative traits such as biomarkers, or endophenotypes, benefit from increased statistical power to identify variants that may not pass the stringent multiple test correction in case-control studies. Endophenotypes also contain additional information helpful for identifying variants and genes associated with other aspects of disease, such as rate of progression or onset, and provide context to interpret the results from genome-wide association studies (GWAS). We conducted GWAS of amyloid beta (Aβ42), tau, and phosphorylated tau (ptau181) levels in cerebrospinal fluid (CSF) from 3146 participants across nine studies to identify novel variants associated with AD. Five genome-wide significant loci (two novel) were associated with ptau181, including loci that have also been associated with AD risk or brain-related phenotypes. Two novel loci associated with Aβ42 near GLIS1 on 1p32.3 (β = -0.059, P = 2.08 × 10-8) and within SERPINB1 on 6p25 (β = -0.025, P = 1.72 × 10-8) were also associated with AD risk (GLIS1: OR = 1.105, P = 3.43 × 10-2), disease progression (GLIS1: β = 0.277, P = 1.92 × 10-2), and age at onset (SERPINB1: β = 0.043, P = 4.62 × 10-3). Bioinformatics indicate that the intronic SERPINB1 variant (rs316341) affects expression of SERPINB1 in various tissues, including the hippocampus, suggesting that SERPINB1 influences AD through an Aβ-associated mechanism. Analyses of known AD risk loci suggest CLU and FERMT2 may influence CSF Aβ42 (P = 0.001 and P = 0.009, respectively) and the INPP5D locus may affect ptau181 levels (P = 0.009); larger studies are necessary to verify these results. Together the findings from this study can be used to inform future AD studies.