Browsing by Author "Price, Nathan D."

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    Metabolic Network Analysis Reveals Altered Bile Acid Synthesis and Metabolism in Alzheimer’s Disease
    (Cell Press, 2020-11-17) Baloni, Priyanka; Funk, Cory C.; Yan, Jingwen; Yurkovich, James T.; Kueider-Paisley, Alexandra; Nho, Kwangsik; Heinken, Almut; Jia, Wei; Mahmoudiandehkordi, Siamak; Louie, Gregory; Saykin, Andrew J.; Arnold, Matthias; Kastenmüller, Gabi; Griffiths, William J.; Thiele, Ines; Kaddurah-Daouk, Rima; Price, Nathan D.; Radiology and Imaging Sciences, School of Medicine
    Increasing evidence suggests Alzheimer's disease (AD) pathophysiology is influenced by primary and secondary bile acids, the end product of cholesterol metabolism. We analyze 2,114 post-mortem brain transcriptomes and identify genes in the alternative bile acid synthesis pathway to be expressed in the brain. A targeted metabolomic analysis of primary and secondary bile acids measured from post-mortem brain samples of 111 individuals supports these results. Our metabolic network analysis suggests that taurine transport, bile acid synthesis, and cholesterol metabolism differ in AD and cognitively normal individuals. We also identify putative transcription factors regulating metabolic genes and influencing altered metabolism in AD. Intriguingly, some bile acids measured in brain tissue cannot be explained by the presence of enzymes responsible for their synthesis, suggesting that they may originate from the gut microbiome and are transported to the brain. These findings motivate further research into bile acid metabolism in AD to elucidate their possible connection to cognitive decline.
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    Multi-Omic analyses characterize the ceramide/sphingomyelin pathway as a therapeutic target in Alzheimer's disease
    (Springer Nature, 2022-10-08) Baloni, Priyanka; Arnold, Matthias; Buitrago, Luna; Nho, Kwangsik; Moreno, Herman; Huynh, Kevin; Brauner, Barbara; Louie, Gregory; Kueider-Paisley, Alexandra; Suhre, Karsten; Saykin, Andrew J.; Ekroos, Kim; Meikle, Peter J.; Hood, Leroy; Price, Nathan D.; The Alzheimer’s Disease Metabolomics Consortium; Doraiswamy, P. Murali; Funk, Cory C.; Hernández, A. Iván; Kastenmüller, Gabi; Baillie, Rebecca; Han, Xianlin; Kaddurah-Daouk, Rima; Radiology and Imaging Sciences, School of Medicine
    Dysregulation of sphingomyelin and ceramide metabolism have been implicated in Alzheimer's disease. Genome-wide and transcriptome-wide association studies have identified various genes and genetic variants in lipid metabolism that are associated with Alzheimer's disease. However, the molecular mechanisms of sphingomyelin and ceramide disruption remain to be determined. We focus on the sphingolipid pathway and carry out multi-omics analyses to identify central and peripheral metabolic changes in Alzheimer's patients, correlating them to imaging features. Our multi-omics approach is based on (a) 2114 human post-mortem brain transcriptomics to identify differentially expressed genes; (b) in silico metabolic flux analysis on context-specific metabolic networks identified differential reaction fluxes; (c) multimodal neuroimaging analysis on 1576 participants to associate genetic variants in sphingomyelin pathway with Alzheimer's disease pathogenesis; (d) plasma metabolomic and lipidomic analysis to identify associations of lipid species with dysregulation in Alzheimer's; and (e) metabolite genome-wide association studies to define receptors within the pathway as a potential drug target. We validate our hypothesis in amyloidogenic APP/PS1 mice and show prolonged exposure to fingolimod alleviated synaptic plasticity and cognitive impairment in mice. Our integrative multi-omics approach identifies potential targets in the sphingomyelin pathway and suggests modulators of S1P metabolism as possible candidates for Alzheimer's disease treatment.