Browsing by Author "Wang, Xiaodong"

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    AD Informer Set: Chemical tools to facilitate Alzheimer's disease drug discovery
    (Wiley, 2022-04-20) Potjewyd, Frances M.; Annor-Gyamfi, Joel K.; Aubé, Jeffrey; Chu, Shaoyou; Conlon, Ivie L.; Frankowski, Kevin J.; Guduru, Shiva K.R.; Hardy, Brian P.; Hopkins, Megan D.; Kinoshita, Chizuru; Kireev, Dmitri B.; Mason, Emily R.; Moerk, Charles T.; Nwogbo, Felix; Pearce, Kenneth H.; Richardson, Timothy I.; Rogers, David A.; Soni, Disha M.; Stashko, Michael; Wang, Xiaodong; Wells, Carrow; Willson, Timothy M.; Frye, Stephen V.; Young, Jessica E.; Axtman, Alison D.; Medicine, School of Medicine
    Introduction: The portfolio of novel targets to treat Alzheimer's disease (AD) has been enriched by the Accelerating Medicines Partnership Program for Alzheimer's Disease (AMP AD) program. Methods: Publicly available resources, such as literature and databases, enabled a data-driven effort to identify existing small molecule modulators for many protein products expressed by the genes nominated by AMP AD and suitable positive control compounds to be included in the set. Compounds contained within the set were manually selected and annotated with associated published, predicted, and/or experimental data. Results: We built an annotated set of 171 small molecule modulators targeting 98 unique proteins that have been nominated by AMP AD consortium members as novel targets for the treatment of AD. The majority of compounds included in the set are inhibitors. These small molecules vary in their quality and should be considered chemical tools that can be used in efforts to validate therapeutic hypotheses, but which will require further optimization. A physical copy of the AD Informer Set can be requested on the Target Enablement to Accelerate Therapy Development for Alzheimer's Disease (TREAT-AD) website. Discussion: Small molecules that enable target validation are important tools for the translation of novel hypotheses into viable therapeutic strategies for AD.
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    Astrocytic GABA transporter 1 deficit in novel SLC6A1 variants mediated epilepsy: Connected from protein destabilization to seizures in mice and humans
    (Elsevier, 2022) Mermer, Felicia; Poliquin, Sarah; Zhou, Shuizhen; Wang, Xiaodong; Ding, Yifeng; Yin, Fei; Shen, Wangzhen; Wang, Juexin; Rigsby, Kathryn; Xu, Dong; Mack, Taralynn; Nwosu, Gerald; Flamm, Carson; Stein, Matthew; Kang, Jing-Qiong; Biomedical Engineering and Informatics, Luddy School of Informatics, Computing, and Engineering
    Objective: Mutations in γ-aminobutyric acid (GABA) transporter 1 (GAT-1)-encoding SLC6A1 have been associated with myoclonic atonic epilepsy and other phenotypes. We determined the patho-mechanisms of the mutant GAT-1, in order to identify treatment targets. Methods: We conducted whole-exome sequencing of patients with myoclonic atonic epilepsy (MAE) and characterized the seizure phenotypes and EEG patterns. We studied the protein stability and structural changes with homology modeling and machine learning tools. We characterized the function and trafficking of the mutant GAT-1 with 3H radioactive GABA uptake assay and confocal microscopy. We utilized different models including a knockin mouse and human astrocytes derived from induced pluripotent stem cells (iPSCs). We focused on astrocytes because of their direct impact of astrocytic GAT-1 in seizures. Results: We identified four novel SLC6A1 variants associated with MAE and 2 to 4 Hz spike-wave discharges as a common EEG feature. Machine learning tools predicted that the variant proteins are destabilized. The variant protein had reduced expression and reduced GABA uptake due to endoplasmic reticular retention. The consistent observation was made in cortical and thalamic astrocytes from variant-knockin mice and human iPSC-derived astrocytes. The Slc6a+/A288V mouse, representative of MAE, had increased 5-7 Hz spike-wave discharges and absence seizures. Interpretation: SLC6A1 variants in various locations of the protein peptides can cause MAE with similar seizure phenotypes and EEG features. Reduced GABA uptake is due to decreased functional GAT-1, which, in thalamic astrocytes, could result in increased extracellular GABA accumulation and enhanced tonic inhibition, leading to seizures and abnormal EEGs.
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    Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome
    (Elsevier, 2021-11) Weerts, Marjolein J.A.; Lanko, Kristina; Guzmán-Vega, Francisco J.; Jackson, Adam; Ramakrishnan, Reshmi; Cardona-Londoño, Kelly J.; Peña-Guerra, Karla A.; van Bever, Yolande; van Paassen, Barbara W.; Kievit, Anneke; van Slegtenhorst, Marjon; Allen, Nicholas M.; Kehoe, Caroline M.; Robinson, Hannah K.; Pang, Lewis; Banu, Selina H.; Zaman, Mashaya; Efthymiou, Stephanie; Houlden, Henry; Järvelä, Irma; Lauronen, Leena; Määttä, Tuomo; Schrauwen, Isabelle; Leal, Suzanne M.; Ruivenkamp, Claudia A.L.; Barge-Schaapveld, Daniela Q.C.M.; Peeters-Scholte, Cacha M.P.C.D.; Galehdari, Hamid; Mazaheri, Neda; Sisodiya, Sanjay M.; Harrison, Victoria; Sun, Angela; Thies, Jenny; Pedroza, Luis Alberto; Lara-Taranchenko, Yana; Chinn, Ivan K.; Lupski, James R.; Garza-Flores, Alexandra; McGlothlin, Jeffery; Yang, Lin; Huang, Shaoping; Wang, Xiaodong; Jewett, Tamison; Rosso, Gretchen; Lin, Xi; Mohammed, Shehla; Merritt, J. Lawrence, II.; Mirzaa, Ghayda M.; Timms, Andrew E.; Scheck, Joshua; Elting, Mariet W.; Polstra, Abeltje M.; Schenck, Lauren; Ruzhnikov, Maura R.Z.; Vetro, Annalisa; Montomoli, Martino; Guerrini, Renzo; Koboldt, Daniel C.; Mihalic Mosher, Theresa; Pastore, Matthew T.; McBride, Kim L.; Peng, Jing; Pan, Zou; Willemsen, Marjolein; Koning, Susanne; Turnpenny, Peter D.; de Vries, Bert B.A.; Gilissen, Christian; Pfundt, Rolph; Lees, Melissa; Braddock, Stephen R.; Klemp, Kara C.; Vansenne, Fleur; van Gijn, Marielle E.; Quindipan, Catherine; Deardorff, Matthew A.; Hamm, J. Austin; Putnam, Abbey M.; Baud, Rebecca; Walsh, Laurence; Lynch, Sally A.; Baptista, Julia; Person, Richard E.; Monaghan, Kristin G.; Crunk, Amy; Keller-Ramey, Jennifer; Reich, Adi; Elloumi, Houda Zghal; Alders, Marielle; Kerkhof, Jennifer; McConkey, Haley; Haghshenas, Sadegheh; Maroofian, Reza; Sadikovic, Bekim; Banka, Siddharth; Arold, Stefan T.; Barakat, Tahsin Stefan; Medical and Molecular Genetics, School of Medicine
    Purpose: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort. Methods: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. Results: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. Conclusion: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.
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    Use of AD Informer Set compounds to explore validity of novel targets in Alzheimer's disease pathology
    (Wiley, 2022-04-12) Potjewyd, Frances M.; Annor-Gyamfi, Joel K.; Aubé, Jeffrey; Chu, Shaoyou; Conlon, Ivie L.; Frankowski, Kevin J.; Guduru, Shiva K.R.; Hardy, Brian P.; Hopkins, Megan D.; Kinoshita, Chizuru; Kireev, Dmitri B.; Mason, Emily R.; Moerk, Charles T.; Nwogbo, Felix; Pearce, Kenneth H., Jr.; Richardson, Timothy I.; Rogers, David A.; Soni, Disha M.; Stashko, Michael; Wang, Xiaodong; Wells, Carrow; Willson, Timothy M.; Frye, Stephen V.; Young, Jessica E.; Axtman, Alison D.; Medicine, School of Medicine
    Introduction: A chemogenomic set of small molecules with annotated activities and implicated roles in Alzheimer's disease (AD) called the AD Informer Set was recently developed and made available to the AD research community: https://treatad.org/data-tools/ad-informer-set/. Methods: Small subsets of AD Informer Set compounds were selected for AD-relevant profiling. Nine compounds targeting proteins expressed by six AD-implicated genes prioritized for study by Target Enablement to Accelerate Therapy Development for Alzheimer's Disease (TREAT-AD) teams were selected for G-protein coupled receptor (GPCR), amyloid beta (Aβ) and tau, and pharmacokinetic (PK) studies. Four non-overlapping compounds were analyzed in microglial cytotoxicity and phagocytosis assays. Results: The nine compounds targeting CAPN2, EPHX2, MDK, MerTK/FLT3, or SYK proteins were profiled in 46 to 47 primary GPCR binding assays. Human induced pluripotent stem cell (iPSC)-derived neurons were treated with the same nine compounds and secretion of Aβ peptides (Aβ40 and Aβ42) as well as levels of phosphophorylated tau (p-tau, Thr231) and total tau (t-tau) peptides measured at two concentrations and two timepoints. Finally, CD1 mice were dosed intravenously to determine preliminary PK and/or brain-specific penetrance values for these compounds. As a final cell-based study, a non-overlapping subset of four compounds was selected based on single-concentration screening for analysis of both cytotoxicity and phagocytosis in murine and human microglia cells. Discussion: We have demonstrated the utility of the AD Informer Set in the validation of novel AD hypotheses using biochemical, cellular (primary and immortalized), and in vivo studies. The selectivity for their primary targets versus essential GPCRs in the brain was established for our compounds. Statistical changes in tau, p-tau, Aβ40, and/or Aβ42 and blood-brain barrier penetrance were observed, solidifying the utility of specific compounds for AD. Single-concentration phagocytosis results were validated as predictive of dose-response findings. These studies established workflows, validated assays, and illuminated next steps for protein targets and compounds.