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Bhore N, Wang BJ, Wu PF, Lee YL, Chen YW, Hsu WM, Lee H, Huang YS, Yang DI, Liao YF. Dual-Specificity Phosphatase 15 (DUSP15) Modulates Notch Signaling by Enhancing the Stability of Notch Protein. Mol Neurobiol 2021; 58:2204-2214. [PMID: 33417224 DOI: 10.1007/s12035-020-02254-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 12/08/2020] [Indexed: 11/27/2022]
Abstract
Dual-specificity phosphatases (DUSPs) comprise a unique group of enzymes that dephosphorylate signaling proteins at both phospho-serine/threonine and phospho-tyrosine residues. Since Notch signaling is an essential pathway for neuronal cell fate determination and development that is also upregulated in Alzheimer's disease tissues, we sought to explore whether and how DUSPs may impact Notch processing. Our results show that overexpression of DUSP15 concomitantly and dose-dependently increased the steady-state levels of recombinant Notch (extracellular domain-truncated Notch, NotchΔE) protein and its cleaved product, Notch intracellular domain (NICD). The overall ratio of NotchΔE to NICD was unchanged by overexpression of DUSP15, suggesting that the effect is independent of γ-secretase. Interestingly, overexpression of DUSP15 also dose-dependently increased phosphorylated ERK1/2. Phosphorylated ERK1/2 is known to be positively correlated with Notch protein level, and we found that DUSP15-mediated regulation of Notch was dependent on ERK1/2 activity. Together, our findings reveal the existence of a previously unidentified DUSP15-ERK1/2-Notch signaling axis, which could potentially play a role in neuronal differentiation and neurological disease.
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Affiliation(s)
- Noopur Bhore
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, ICOB 238, 128 Sec. 2 Academia Rd, Taipei, 11529, Taiwan.,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University, Academia Sinica, Taipei, Taiwan
| | - Bo-Jeng Wang
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, ICOB 238, 128 Sec. 2 Academia Rd, Taipei, 11529, Taiwan
| | - Po-Fan Wu
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, ICOB 238, 128 Sec. 2 Academia Rd, Taipei, 11529, Taiwan.,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University, Academia Sinica, Taipei, Taiwan
| | - Yen-Lurk Lee
- TIGP in Molecular Medicine, National Yang-Ming University, Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yun-Wen Chen
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, ICOB 238, 128 Sec. 2 Academia Rd, Taipei, 11529, Taiwan
| | - Wen-Ming Hsu
- Department of Surgery, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hsinyu Lee
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Yi-Shuian Huang
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University, Academia Sinica, Taipei, Taiwan.,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University, Academia Sinica, Taipei, Taiwan.,TIGP in Molecular Medicine, National Yang-Ming University, Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ding-I Yang
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University, Academia Sinica, Taipei, Taiwan.,Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yung-Feng Liao
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, ICOB 238, 128 Sec. 2 Academia Rd, Taipei, 11529, Taiwan. .,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University, Academia Sinica, Taipei, Taiwan. .,Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University, Academia Sinica, Taipei, Taiwan.
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2
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Law BM, Guest AL, Pullen MWJ, Perkinton MS, Williams RJ. Increased Foxo3a Nuclear Translocation and Activity is an Early Neuronal Response to βγ-Secretase-Mediated Processing of the Amyloid-β Protein Precursor: Utility of an AβPP-GAL4 Reporter Assay. J Alzheimers Dis 2019; 61:673-688. [PMID: 29254083 DOI: 10.3233/jad-170393] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sequential cleavage of the amyloid-β protein precursor (AβPP) by BACE1 (β-secretase) followed by theγ-secretase complex, is strongly implicated in Alzheimer's disease (AD) but the initial cellular responses to these cleavage events are not fully defined. β-secretase-mediated AβPP processing yields an extracellular domain (sAβPPβ) and a C-terminal fragment of AβPP of 99 amino acids (C99). Subsequent cleavage by γ-secretase produces amyloid-β (Aβ) and an AβPP intracellular domain (AICD). A cellular screen based on the generation of AICD from an AβPP-Gal4 fusion protein was adapted by introducing familial AD (FAD) mutations into the AβPP sequence and linking the assay to Gal4-UAS driven luciferase and GFP expression, to identify responses immediately downstream of AβPP processing in neurons with a focus on the transcription factor Foxo3a which has been implicated in neurodegeneration. The K670N/M671L, E682K, E693G, and V717I FAD mutations and the A673T protective mutation, were introduced into the AβPP sequence by site directed mutagenesis. When expressed in mouse cortical neurons, AβPP-Gal4-UAS driven luciferase and GFP expression was substantially reduced by γ-secretase inhibitors, lowered by β-secretase inhibitors, and enhanced by α-secretase inhibitors suggesting that AICD is a product of the βγ-secretase pathway. AβPP-Gal4-UAS driven GFP expression was exploited to identify individual neurons undergoing amyloidogenic AβPP processing, revealing increased nuclear localization of Foxo3a and enhanced Foxo3a-mediated transcription downstream of AICD production. Foxo3a translocation was not driven by AICD directly but correlated with reduced Akt phosphorylation. Collectively this suggests that βγ-secretase-mediated AβPP processing couples to Foxo3a which could be an early neuronal signaling response in AD.
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Affiliation(s)
- Bernard M Law
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Amy L Guest
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | | | | | - Robert J Williams
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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3
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Lei X, Yu J, Niu Q, Liu J, Fraering PC, Wu F. The FDA-approved natural product dihydroergocristine reduces the production of the Alzheimer's disease amyloid-β peptides. Sci Rep 2015; 5:16541. [PMID: 26567970 PMCID: PMC4644980 DOI: 10.1038/srep16541] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/15/2015] [Indexed: 02/05/2023] Open
Abstract
Known γ-secretase inhibitors or modulators display an undesirable pharmacokinetic profile and toxicity and have therefore not been successful in clinical trials for Alzheimer's disease (AD). So far, no compounds from natural products have been identified as direct inhibitors of γ-secretase. To search for bioactive molecules that can reduce the amount of amyloid-beta peptides (Aβ) and that have better pharmacokinetics and an improved safety profile, we completed a screen of ~400 natural products by using cell-based and cell-free γ-secretase activity assays. We identified dihydroergocristine (DHEC), a component of an FDA- (Food and Drug Administration)-approved drug, to be a direct inhibitor of γ-secretase. Micromolar concentrations of DHEC substantially reduced Aβ levels in different cell types, including a cell line derived from an AD patient. Structure-activity relationship studies implied that the key moiety for inhibiting γ-secretase is the cyclized tripeptide moiety of DHEC. A Surface Plasmon Resonance assay showed that DHEC binds directly to γ-secretase and Nicastrin, with equilibrium dissociation constants (Kd) of 25.7 nM and 9.8 μM, respectively. This study offers DHEC not only as a new chemical moiety for selectively modulating the activity of γ-secretase but also a candidate for drug repositioning in Alzheimer's disease.
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Affiliation(s)
- Xiling Lei
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Yu
- State Key Laboratory of Microbial Metabolism & School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qi Niu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianhua Liu
- State Key Laboratory of Microbial Metabolism & School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Patrick C. Fraering
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland
| | - Fang Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
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4
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Mentrup T, Häsler R, Fluhrer R, Saftig P, Schröder B. A Cell-Based Assay Reveals Nuclear Translocation of Intracellular Domains Released by SPPL Proteases. Traffic 2015; 16:871-92. [DOI: 10.1111/tra.12287] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/26/2015] [Accepted: 03/26/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Torben Mentrup
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Robert Häsler
- Institute of Clinical Molecular Biology; Christian Albrechts University of Kiel; Schittenhelmstr. 12 D-24105 Kiel Germany
| | - Regina Fluhrer
- Biomedizinisches Centrum (BMC); Ludwig Maximilians University of Munich; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
- DZNE - German Center for Neurodegenerative Diseases; Feodor-Lynen-Strasse 17 D-81377 Munich Germany
| | - Paul Saftig
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
| | - Bernd Schröder
- Biochemical Institute; Christian Albrechts University of Kiel; Otto-Hahn-Platz 9 D-24118 Kiel Germany
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5
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Liao YF, Tang YC, Chang MY, Wang BJ, Hu MK. Discovery of small molecular (d)-leucinamides as potent, Notch-sparing γ-secretase modulators. Eur J Med Chem 2014; 79:143-51. [PMID: 24732790 DOI: 10.1016/j.ejmech.2014.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 03/22/2014] [Accepted: 04/04/2014] [Indexed: 02/04/2023]
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6
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Chen CY, Liao YF, Chang MY, Hu MK. Difluorophenylglycinols as new modulators of proteolytic processing of amyloid precursor proteins. Arch Pharm (Weinheim) 2013; 347:161-73. [PMID: 24339192 DOI: 10.1002/ardp.201300283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/07/2013] [Accepted: 09/17/2013] [Indexed: 11/06/2022]
Abstract
Synthesis and evaluation of difluorophenylglycinols as new modulators of proteolytic processing of the amyloid-β precursor proteins for Alzheimer's therapies were described. A range of N-substituted (R)- and (S)-difluorophenylglycinols, structured on the amino alcohol framework, were explored by incorporating the arylsulfonyl moieties and various N-substituents. Evans' chiral auxiliary strategy was employed for the asymmetric synthesis of these enantiomeric difluorophenylglycinols. Compounds with effects on the γ-secretase inhibition and ERK-mediated signaling pathways were evaluated on cell-based assays. Among them, N-cyclopropylmethyl derivatives R-12c and R-13c showed modest γ-secretase inhibition as well as ERK-dependent activation.
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Affiliation(s)
- Chia-Yu Chen
- School of Pharmacy, National Defense Medical Center, Taipei, Taiwan
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7
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Kapoor A, Wang BJ, Hsu WM, Chang MY, Liang SM, Liao YF. Retinoic acid-elicited RARα/RXRα signaling attenuates Aβ production by directly inhibiting γ-secretase-mediated cleavage of amyloid precursor protein. ACS Chem Neurosci 2013; 4:1093-100. [PMID: 23530929 DOI: 10.1021/cn400039s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Retinoic acid (RA)-elicited signaling has been shown to play critical roles in development, organogenesis, and the immune response. RA regulates expression of Alzheimer's disease (AD)-related genes and attenuates amyloid pathology in a transgenic mouse model. In this study, we investigated whether RA can suppress the production of amyloid-β (Aβ) through direct inhibition of γ-secretase activity. We report that RA treatment of cells results in significant inhibition of γ-secretase-mediated processing of the amyloid precursor protein C-terminal fragment APP-C99, compared with DMSO-treated controls. RA-elicited signaling was found to significantly increase accumulation of APP-C99 and decrease production of secreted Aβ40. In addition, RA-induced inhibition of γ-secretase activity was found to be mediated through significant activation of extracellular signal-regulated kinases (ERK1/2). Treatment of cells with the specific ERK inhibitor PD98059 completely abolished RA-mediated inhibition of γ-secretase. Consistent with these findings, RA was observed to inhibit secretase-mediated proteolysis of full-length APP. Finally, we have established that RA inhibits γ-secretase through nuclear retinoic acid receptor-α (RARα) and retinoid X receptor-α (RXRα). Our findings provide a new mechanistic explanation for the neuroprotective role of RA in AD pathology and add to the previous data showing the importance of RA signaling as a target for AD therapy.
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Affiliation(s)
- Arun Kapoor
- Molecular and Biological Agricultural Sciences Program,
Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei 11529, Taiwan
- Graduate Institute of Biotechnology
and Department of Life Sciences, National Chung-Hsing University, Taichung 402, Taiwan
| | - Bo-Jeng Wang
- Institute of Zoology, National Taiwan University, Taipei 106, Taiwan
| | - Wen-Ming Hsu
- Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 100, Taiwan
| | | | | | - Yung-Feng Liao
- Graduate Institute of Biotechnology
and Department of Life Sciences, National Chung-Hsing University, Taichung 402, Taiwan
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8
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Niles AL, Moravec RA, Riss TL. Update on in vitro cytotoxicity assays for drug development. Expert Opin Drug Discov 2013; 3:655-69. [PMID: 23506147 DOI: 10.1517/17460441.3.6.655] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND in vitro cytotoxicity testing provides a crucial means of ranking compounds for consideration in drug discovery. The choice of using a particular viability or cytotoxicity assay technology may be influenced by specific research goals. OBJECTIVE Although the high-throughput screening (HTS) utility is typically dependent upon sensitivity and scalability, it is also impacted by signal robustness and resiliency to assay interferences. Further consideration should be given to data quality, ease-of-use, reagent stability, and matters of cost-effectiveness. METHODS Here we focus on three main classes of assays that are at present the most popular, useful, and practical for HTS drug discovery efforts. These methods measure: i) viability by metabolism reductase activities; ii) viability by bioluminescent ATP assays; or iii) cytotoxicity by enzymes 'released' into culture medium. Multi-parametric technologies are also briefly discussed. RESULTS/CONCLUSION Each of these methods has its relative merits and detractions; however multi-parametric methods using both viability and cytotoxicity markers may mitigate the inherent shortcomings of single parameter measures.
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Affiliation(s)
- Andrew L Niles
- Senior Research Scientist Promega Corporation, Research and Development, 2800 Woods Hollow Road, Madison, Wisconsin, 53711, USA +1 608 247 4330, ext. 1447 ; +1 608 298 4818 ;
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9
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Wu F, Schweizer C, Rudinskiy N, Taylor DM, Kazantsev A, Luthi-Carter R, Fraering PC. Novel gamma-secretase inhibitors uncover a common nucleotide-binding site in JAK3, SIRT2, and PS1. FASEB J 2010; 24:2464-74. [PMID: 20237298 DOI: 10.1096/fj.09-148031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Gamma-secretase is an intramembrane-cleaving protease responsible for the final proteolytic event in the production of the amyloid-beta peptides (Abeta) implicated in Alzheimer's disease (AD). Inhibition of gamma-secretase activity is thus an attractive therapeutic strategy to slow down the pathogenesis of AD. Drugs often target more than one biomolecule because of conserved 3-dimensional structures in prospective protein binding sites. We have capitalized on this phenomenon of nature to identify new gamma-secretase inhibitors. Here we show that 2-hydroxy naphthyl derivatives, a previously identified subclass of NAD(+) analog inhibitors of sirtuin 2 (SIRT2), are direct gamma-secretase inhibitors. Subsequent structure-activity relationship studies further showed that 2-hydroxy-1-naphthaldehyde is the minimal pharmacophore for gamma-secretase inhibition. In evaluating target protein determinants of inhibition, we identified a common GXG signature nucleotide-binding site (NBS) shared by the gamma-secretase subunit presenilin-1 C-terminal fragment (PS1-CTF), SIRT2, and Janus kinase 3 (JAK3). Because a detailed 3-dimensional structure of gamma-secretase is beyond our knowledge, we took advantage of the known crystal structure of human JAK3 to model the NBS of the PS1-CTF, which includes the catalytic residue D385. Our results suggest that the flexible PS1-CTF (381)LGLG(384) loop comprises a substrate-docking site capable of recognizing specifically different gamma-secretase substrates.
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Affiliation(s)
- Fang Wu
- Laboratory of Molecular and Cellular Biology of Alzheimer's Disease, Brain Mind Institute and School of Life Sciences, Swiss Federal Institute of Technology, Lausanne, Switzerland
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10
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Shelton CC, Tian Y, Shum D, Radu C, Djaballah H, Li YM. A miniaturized 1536-well format gamma-secretase assay. Assay Drug Dev Technol 2010; 7:461-70. [PMID: 19715456 DOI: 10.1089/adt.2009.0202] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
gamma-Secretase is an aspartyl protease that cleaves multiple substrates including the amyloid precursor protein (APP) and the Notch proteins. Abnormal proteolysis of APP is involved in the pathogenesis of Alzheimer's disease (AD) and overactive Notch signaling plays an oncogenic role in a variety of cancers. gamma-Secretase has emerged as a promising target for drug development in the treatment of AD and cancer. Assays with increased capacity for high-throughput screening would allow for quicker screening of chemical libraries and facilitate inhibitor development. We have developed a homogeneous time-resolved fluorescence (HTRF)-based assay that makes use of a novel biotinylated recombinant APP substrate and solubilized membrane preparation as the source of the gamma-secretase enzyme. The assay was miniaturized to a 1536-well format and validated in a pilot screen against a library of approximately 3,000 compounds. The overall assay performance was robust due to a calculated Z' factor of 0.74 and its demonstrated ability to identify known gamma-secretase inhibitors such as pepstatin A. This validated assay can readily be used for primary screening against large chemical libraries searching for novel inhibitors of gamma-secretase activity that may represent potential therapeutics for AD and a variety of neoplasms.
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Affiliation(s)
- Christopher C Shelton
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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11
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Chapin HC, Rajendran V, Capasso A, Caplan MJ. Detecting the surface localization and cytoplasmic cleavage of membrane-bound proteins. Methods Cell Biol 2009; 94:223-39. [PMID: 20362093 DOI: 10.1016/s0091-679x(08)94011-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Polycystin-1 (PC1) is a large, membrane-bound protein that localizes to the cilia and is implicated in the common ciliopathy autosomal-dominant polycystic kidney disease. The physiological function of PC1 is dependent upon its subcellular localization as well as specific cleavages that release soluble fragments of its C-terminal tail. The techniques described here allow visualization and quantification of these aspects of the biology of the PC1 protein. To visualize PC1 at the plasma membrane, a live-cell surface labeling immunofluorescence protocol paired with the labeling of an internal antigen motif allows a robust detection of the surface population of this protein. This technique is modified to generate a surface enzyme-linked immunosorbent assay (ELISA), which quantitatively measures the amount of surface protein as a fraction of the total amount of the protein expressed in that cell population. These assays are powerful tools in the assessment of the small but biologically important pool of PC1 that reaches the cell surface. The C-terminal tail cleavage of PC1 constitutes an interesting modification that allows PC1 to extend its functional role into the nucleus. A reporter assay based on Gal4/VP16 luciferase can be used to quantitate the amount of PC1 C-terminal tail that reaches the nucleus. This assay can be paired with quantitative measurement of the protein expression in the cell, allowing a more complete understanding of the pattern of PC1 cleavage and the nuclear localization of the resultant.
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Affiliation(s)
- Hannah C Chapin
- Department of Cell Biology, Yale University, New Haven, Connecticut 06520, USA
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12
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Versatile assays for high throughput screening for activators or inhibitors of intracellular proteases and their cellular regulators. PLoS One 2009; 4:e7655. [PMID: 19876397 PMCID: PMC2764853 DOI: 10.1371/journal.pone.0007655] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 08/06/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Intracellular proteases constitute a class of promising drug discovery targets. Methods for high throughput screening against these targets are generally limited to in vitro biochemical assays that can suffer many technical limitations, as well as failing to capture the biological context of proteases within the cellular pathways that lead to their activation. METHODS #ENTITYSTARTX00026; FINDINGS We describe here a versatile system for reconstituting protease activation networks in yeast and assaying the activity of these pathways using a cleavable transcription factor substrate in conjunction with reporter gene read-outs. The utility of these versatile assay components and their application for screening strategies was validated for all ten human Caspases, a family of intracellular proteases involved in cell death and inflammation, including implementation of assays for high throughput screening (HTS) of chemical libraries and functional screening of cDNA libraries. The versatility of the technology was also demonstrated for human autophagins, cysteine proteases involved in autophagy. CONCLUSIONS Altogether, the yeast-based systems described here for monitoring activity of ectopically expressed mammalian proteases provide a fascile platform for functional genomics and chemical library screening.
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13
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Niles AL, Moravec RA, Riss TL. In vitro viability and cytotoxicity testing and same-well multi-parametric combinations for high throughput screening. CURRENT CHEMICAL GENOMICS 2009; 3:33-41. [PMID: 20161834 PMCID: PMC2802765 DOI: 10.2174/1875397300903010033] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 04/04/2009] [Accepted: 04/17/2009] [Indexed: 11/22/2022]
Abstract
In vitro cytotoxicity testing has become an integral aspect of drug discovery because it is a convenient, costeffective, and predictive means of characterizing the toxic potential of new chemical entities. The early and routine implementation of this testing is testament to its prognostic importance for humans. Although a plethora of assay chemistries and methods exist for 96-well formats, few are practical and sufficiently sensitive enough for application in high throughput screening (HTS). Here we briefly describe a handful of the currently most robust and validated HTS assays for accurate and efficient assessment of cytotoxic risk. We also provide guidance for successful HTS implementation and discuss unique merits and detractions inherent in each method. Lastly, we discuss the advantages of combining specific HTS compatible assays into multi-parametric, same-well formats.
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Affiliation(s)
- Andrew L Niles
- Research Department, Promega Corporation, 2800 Woods Hollow Road, Madison, WI, USA.
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14
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Abstract
Alzheimer's disease (AD) is a progressive chronic disorder that leads to cognitive decline. Several studies have associated up-regulation of some of the chemokines and/or their receptors with altered APP processing leading to increased production of beta-amyloid protein (Abeta) and AD pathological changes. However, there is no direct evidence to date to determine whether the altered processing of APP results in up-regulation of these receptors or whether the up-regulation of the chemokine receptors causes modulated processing of APP. In the current study, we demonstrate that treatment of the chemokine receptor CXCR2 with agonists leads to enhancement of Abeta production and treatment with antagonists or immunodepletion of CXCR2's endogenous agonists leads to Abeta inhibition. Further, we found that the inhibitory effect of the antagonist of CXCR2 on Abeta40 and Abeta42 is mediated via gamma-secretase, specifically through reduction in expression of presenilin (PS), one of the gamma-secretase components. Also, in vivo chronic treatment with a CXCR2 antagonist blocked Abeta40 and Abeta42 production. Using small interfering RNAs for CXCR2, we further showed that knockdown of CXCR2 in vitro accumulates gamma-secretase substrates C99 and C83 with reduced production of both Abeta40 and Abeta42. Taken together, these findings strongly suggest for the first time that up-regulation of the CXCR2 receptor can be the driving force in increased production of Abeta. Our findings unravel new mechanisms involving the CXCR2 receptor in the pathogenesis of AD and pose it as a potential target for developing novel therapeutics for intervention in this disease. Also, we propose here a new chemical series of interest that can serve as a prototype for drug development.
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15
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Abstract
The amyloid-beta peptide (Abeta), implicated in the pathogenesis of Alzheimer's disease (AD), is produced through sequential proteolysis of the Abeta precursor protein (APP) by beta- and gamma-secretases. Thus, blocking either of these two proteases, directly or indirectly, is potentially worthwhile toward developing AD therapeutics. beta-Secretase is a membrane-tethered pepsin-like aspartyl protease suitable for structure-based design, whereas gamma-secretase is an unusual, heterotetrameric membrane-embedded aspartyl protease. While gamma-secretase inhibitors entered clinical trials first due to their superior pharmacological properties (for example, brain penetration) over beta-secretase inhibitors, it has since become clear that gamma-secretase inhibitors can cause mechanism-based toxicities owing to interference with the proteolysis of another gamma-secretase substrate, the Notch receptor. Strategies for targeting Abeta production at the gamma-secretase level without blocking Notch signalling will be discussed. Other strategies utilizing cell-based screening have led to the identification of novel Abeta lowering agents that likewise leave Notch proteolysis intact. The mechanism by which these agents lower Abeta is unknown, but these compounds may ultimately reveal new targets for AD therapeutics.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Diseases, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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16
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Kuo LH, Hu MK, Hsu WM, Tung YT, Wang BJ, Tsai WW, Yen CT, Liao YF. Tumor necrosis factor-alpha-elicited stimulation of gamma-secretase is mediated by c-Jun N-terminal kinase-dependent phosphorylation of presenilin and nicastrin. Mol Biol Cell 2008; 19:4201-12. [PMID: 18667537 DOI: 10.1091/mbc.e07-09-0987] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Gamma-secretase is a multiprotein complex composed of presenilin (PS), nicastrin (NCT), Aph-1, and Pen-2, and it catalyzes the final proteolytic step in the processing of amyloid precursor protein to generate amyloid-beta. Our previous results showed that tumor necrosis factor-alpha (TNF-alpha) can potently stimulate gamma-secretase activity through a c-Jun N-terminal kinase (JNK)-dependent pathway. Here, we demonstrate that TNF-alpha triggers JNK-dependent serine/threonine phosphorylation of PS1 and NCT to stimulate gamma-secretase activity. Blocking of JNK activity with a potent JNK inhibitor (SP600125) reduces TNF-alpha-triggered phosphorylation of PS1 and NCT. Consistent with this, we show that activated JNKs can be copurified with gamma-secretase complexes and that active recombinant JNK2 can promote the phosphorylation of PS1 and NCT in vitro. Using site-directed mutagenesis and a synthetic peptide, we clearly show that the Ser(319)Thr(320) motif in PS1 is an important JNK phosphorylation site that is critical for the TNF-alpha-elicited regulation of gamma-secretase. This JNK phosphorylation of PS1 at Ser(319)Thr(320) enhances the stability of the PS1 C-terminal fragment that is necessary for gamma-secretase activity. Together, our findings strongly suggest that JNK is a critical intracellular mediator of TNF-alpha-elicited regulation of gamma-secretase and governs the pivotal step in the assembly of functional gamma-secretase.
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Affiliation(s)
- Lan-Hsin Kuo
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
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17
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Affiliation(s)
- Wolfgang H Binder
- Vienna University of Technology, Institute of Applied Synthetic Chemistry, Vienna, Austria.
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18
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Rossi C, Padmanaban D, Ni J, Yeh LA, Glicksman MA, Waldner H. Identifying druglike inhibitors of myelin-reactive T cells by phenotypic high-throughput screening of a small-molecule library. ACTA ACUST UNITED AC 2007; 12:481-9. [PMID: 17478482 DOI: 10.1177/1087057107301272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inflammatory T cells that are reactive to myelin protein components of the CNS play a critical role in the pathogenesis of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). The authors have previously generated mice that predominantly harbor T cells transgenic for a T-cell receptor (TCR) that is specific to the myelin proteolipid protein (PLP) 139-151 and that spontaneously develop MS-like paralysis. T cells from healthy transgenic mice respond to stimulation with PLP139-151 in a highly specific manner by proliferation and secretion of proinflammatory cytokines such as interleukin (IL)-2 and interferon (INF)-gamma in vitro. To identify druglike compounds that may inhibit inflammatory T-cell responses, the authors have developed a high-throughput screening assay with primary T cells from PLP TCR transgenic mice. They have screened 41,184 small-molecule compounds that follow Lipinski's rules for their inhibitory activity on the proliferation and secretion of proinflammatory cytokines in PLP-reactive T cells. To this end, the screen identified 6 nontoxic compounds with a molecular weight <500 that inhibited inflammatory responses in PLP-reactive T cells in a concentration-dependent fashion. The identified compounds represent valid leads that may be developed into novel therapeutics for MS that could be administered orally.
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Affiliation(s)
- Christina Rossi
- Center for Neurologic Diseases, Brigham and Women's Hospital, and Harvard Medical School, Cambridge, Massachusetts 02139, USA
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19
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Liao YF, Wang BJ, Hsu WM, Lee H, Liao CY, Wu SY, Cheng HT, Hu MK. Unnatural amino acid-substituted (hydroxyethyl)urea peptidomimetics inhibit gamma-secretase and promote the neuronal differentiation of neuroblastoma cells. Mol Pharmacol 2006; 71:588-601. [PMID: 17105873 DOI: 10.1124/mol.106.024299] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gamma-secretase, exhibiting characteristics of aspartyl protease, mediates the intramembranous proteolysis of beta-amyloid precursor protein (APP) and Notch, and it is considered to be a prime pharmacological target in the development of therapeutics for Alzheimer's disease (AD). To identify compounds that block gamma-secretase-mediated proteolysis, we used a highly sensitive cell-based reporter gene assay for gamma-secretase in which Gal4/VP16-tagged C99-APP was expressed as the immediate substrate of gamma-secretase, and Gal4/VP16-tagged APP intracellular domain released by the gamma-secretase cleavage then activated the expression of the Gal4-driven luciferase reporter gene. Using this reporter assay, we demonstrated that the newly synthesized (hydroxyethyl)urea peptidomimetics, which contain unnatural amino acid moieties at positions P1' and/or P3', can effectively inhibit gamma-secretase activity and significantly reduce Abeta production. The gamma-secretase-dependent S3 cleavage of Notch was also consistently blocked by these (hydroxyethyl)ureas as evidenced by the decreased generation of the Notch intracellular domain, a prerequisite for the activation of Notch signaling. The inhibition of Notch signaling by active Jia compounds efficiently promotes the neuronal differentiation of neuroblastoma cells, intervening in tumorigenesis and the malignancy of neuroblastomas. Our results suggest that (hydroxyethyl)urea peptidomimetics containing unnatural amino acid substitutions could represent a novel class of gamma-secretase inhibitors with enhanced stability, providing the basis for the further development of effective therapeutics for AD and neuroblastomas.
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Affiliation(s)
- Yung-Feng Liao
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Rm 238, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei 115, Taiwan.
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20
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21
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Schwimmer C, Rak M, Lefebvre-Legendre L, Duvezin-Caubet S, Plane G, di Rago JP. Yeast models of human mitochondrial diseases: from molecular mechanisms to drug screening. Biotechnol J 2006; 1:270-81. [PMID: 16897707 DOI: 10.1002/biot.200500053] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondrial diseases are rare diseases most often linked to energy in the form of ATP-depletion. The high number of nuclear- and mitochondrial-DNA-encoded proteins (>500), required for ATP production and other crucial mitochondrial functions such as NADH re-oxidation, explains the increasing number of reported disorders. In recent years, yeast has revealed to be a powerful model to identify responsible genes, to study primary effects of pathogenic mutations and to determine the molecular mechanisms leading to mitochondrial disorders. However, the clinical management of patients with mitochondrial disorders is still essentially supportive. Here we review some of the most fruitful yeast mitochondrial disorder models and propose to subject these models to highthroughput chemical library screening to prospect new therapeutic drugs against mitochondrial diseases.
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Bandyopadhyay S, Ni J, Ruggiero A, Walshe K, Rogers MS, Chattopadhyay N, Glicksman MA, Rogers JT. A high-throughput drug screen targeted to the 5'untranslated region of Alzheimer amyloid precursor protein mRNA. ACTA ACUST UNITED AC 2006; 11:469-80. [PMID: 16928984 DOI: 10.1177/1087057106287271] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The authors employed a novel approach to identify therapeutics effective in Alzheimer disease (AD). The 5'untranslated region (5'UTR) of the mRNA of AD amyloid precursor protein (APP) is a significant regulator of the levels of the APP holoprotein and amyloid beta (Abeta) peptide in the central nervous system. The authors generated stable neuroblastoma SH-SY5Y transfectants that express luciferase under the translational control of the 146-nucleotide APP mRNA 5'UTR and green fluorescent protein (GFP) driven by a viral internal ribosomal entry site. Using a high-throughput screen (HTS), they screened for the effect of 110,000 compounds obtained from the library of the Laboratory for Drug Discovery on Neurodegeneration (LDDN) on the APP mRNA 5'UTR-controlled translation of the luciferase reporter. This screening yielded several nontoxic specific inhibitors of APP mRNA 5'UTR-driven luciferase that had no effect on the GFP expression in the stable SH-SY5Y transfectants. Moreover, these compounds either did not inhibit or inhibited to a much lower extent the expression of the luciferase reporter regulated by a prion protein (PrP) mRNA 5'UTR, used as an alternative mRNA structure to counterscreen APP mRNA 5'UTR in stably transfected SH-SY5Y cell lines. The hits obtained from this robust, specific, and highly quantitative HTS will be characterized to identify agents that may be developed into useful future therapeutic agents to limit APP translation and Abeta production for AD.
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Affiliation(s)
- Sanghamitra Bandyopadhyay
- Neurochemistry Laboratory, Genetics and Aging Research Unit, Psychiatry Department, Massachusetts General Hospital, Boston, MA, USA, and School of Biological and Environmental Science, University College Dublin, Belfield, Ireland
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