Browsing by Author "Xia, Weiming"

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    Alzheimer’s Disease Heterogeneity Explained by Polygenic Risk Scores Derived from Brain Transcriptomic Profiles
    (Wiley, 2023) Chung, Jaeyoon; Sahelijo, Nathan; Maruyama, Toru; Hu, Junming; Panitch, Rebecca; Xia, Weiming; Mez, Jesse; Stein, Thor D.; Alzheimer’s Disease Neuroimaging Initiative; Saykin, Andrew J.; Takeyama, Haruko; Farrer, Lindsay A.; Crane, Paul K.; Nho, Kwangsik; Jun, Gyungah R.; Radiology and Imaging Sciences, School of Medicine
    Introduction: Alzheimer's disease (AD) is heterogeneous, both clinically and neuropathologically. We investigated whether polygenic risk scores (PRSs) integrated with transcriptome profiles from AD brains can explain AD clinical heterogeneity. Methods: We conducted co-expression network analysis and identified gene sets (modules) that were preserved in three AD transcriptome datasets and associated with AD-related neuropathological traits including neuritic plaques (NPs) and neurofibrillary tangles (NFTs). We computed the module-based PRSs (mbPRSs) for each module and tested associations with mbPRSs for cognitive test scores, cognitively defined AD subgroups, and brain imaging data. Results: Of the modules significantly associated with NPs and/or NFTs, the mbPRSs from two modules (M6 and M9) showed distinct associations with language and visuospatial functioning, respectively. They matched clinical subtypes and brain atrophy at specific regions. Discussion: Our findings demonstrate that polygenic profiling based on co-expressed gene sets can explain heterogeneity in AD patients, enabling genetically informed patient stratification and precision medicine in AD. Highlights: Co-expression gene-network analysis in Alzheimer's disease (AD) brains identified gene sets (modules) associated with AD heterogeneity. AD-associated modules were selected when genes in each module were enriched for neuritic plaques and neurofibrillary tangles. Polygenic risk scores from two selected modules were linked to the matching cognitively defined AD subgroups (language and visuospatial subgroups). Polygenic risk scores from the two modules were associated with cognitive performance in language and visuospatial domains and the associations were confirmed in regional-specific brain atrophy data.
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    Protein phosphatase 2A and complement component 4 are linked to the protective effect of APOE ɛ2 for Alzheimer's disease
    (Wiley, 2022) Jun, Gyungah R.; You, Yang; Zhu, Congcong; Meng, Gaoyuan; Chung, Jaeyoon; Panitch, Rebecca; Hu, Junming; Xia, Weiming; The Alzheimer’s Disease Genetics Consortium; Bennett, David A.; Foroud, Tatiana M.; Wang, Li-San; Haines, Jonathan L.; Mayeux, Richard; Pericak-Vance, Margaret A.; Schellenberg, Gerard D.; Au, Rhoda; Lunetta, Kathryn L.; Ikezu, Tsuneya; Stein, Thor D.; Farrer, Lindsay A.; Medical and Molecular Genetics, School of Medicine
    Introduction: The apolipoprotein E (APOE) ɛ2 allele reduces risk against Alzheimer's disease (AD) but mechanisms underlying this effect are largely unknown. Methods: We conducted a genome-wide association study for AD among 2096 ɛ2 carriers. The potential role of the top-ranked gene and complement 4 (C4) proteins, which were previously linked to AD in ɛ2 carriers, was investigated using human isogenic APOE allele-specific induced pluripotent stem cell (iPSC)-derived neurons and astrocytes and in 224 neuropathologically examined human brains. Results: PPP2CB rs117296832 was the second most significantly associated single nucleotide polymorphism among ɛ2 carriers (P = 1.1 × 10-7 ) and the AD risk allele increased PPP2CB expression in blood (P = 6.6 × 10-27 ). PPP2CB expression was correlated with phosphorylated tau231/total tau ratio (P = .01) and expression of C4 protein subunits C4A/B (P = 2.0 × 10-4 ) in the iPSCs. PPP2CB (subunit of protein phosphatase 2A) and C4b protein levels were correlated in brain (P = 3.3 × 10-7 ). Discussion: PP2A may be linked to classical complement activation leading to AD-related tau pathology.
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    Protein phosphatase 2A and complement component 4 are linked to the protective effect of APOE ɛ2 for Alzheimer's disease
    (Wiley, 2022-11) Jun, Gyungah R.; You, Yang; Zhu, Congcong; Meng, Gaoyuan; Chung, Jaeyoon; Panitch, Rebecca; Hu, Junming; Xia, Weiming; The Alzheimer's Disease Genetics Consortium; Bennett, David A.; Foroud, Tatiana M.; Wang, Li-San; Haines, Jonathan L.; Mayeux, Richard; Pericak-Vance, Margaret A.; Schellenberg, Gerard D.; Au, Rhoda; Lunetta, Kathryn L.; Ikezu, Tsuneya; Stein, Thor D.; Farrer, Lindsay A.; Medical and Molecular Genetics, School of Medicine
    Introduction The apolipoprotein E (APOE) ɛ2 allele reduces risk against Alzheimer's disease (AD) but mechanisms underlying this effect are largely unknown. Methods We conducted a genome‐wide association study for AD among 2096 ɛ2 carriers. The potential role of the top‐ranked gene and complement 4 (C4) proteins, which were previously linked to AD in ɛ2 carriers, was investigated using human isogenic APOE allele‐specific induced pluripotent stem cell (iPSC)–derived neurons and astrocytes and in 224 neuropathologically examined human brains. Results PPP2CB rs117296832 was the second most significantly associated single nucleotide polymorphism among ɛ2 carriers (P = 1.1 × 10−7) and the AD risk allele increased PPP2CB expression in blood (P = 6.6 × 10−27). PPP2CB expression was correlated with phosphorylated tau231/total tau ratio (P = .01) and expression of C4 protein subunits C4A/B (P = 2.0 × 10−4) in the iPSCs. PPP2CB (subunit of protein phosphatase 2A) and C4b protein levels were correlated in brain (P = 3.3 × 10−7). Discussion PP2A may be linked to classical complement activation leading to AD‐related tau pathology.