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Boubertakh B, Courtemanche O, Marsolais D, Di Marzo V, Silvestri C. New role for the anandamide metabolite prostaglandin F 2α ethanolamide: Rolling preadipocyte proliferation. J Lipid Res 2023; 64:100444. [PMID: 37730163 PMCID: PMC10622703 DOI: 10.1016/j.jlr.2023.100444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 08/24/2023] [Accepted: 09/11/2023] [Indexed: 09/22/2023] Open
Abstract
White adipose tissue regulation is key to metabolic health, yet still perplexing. The chief endocannabinoid anandamide metabolite, prostaglandin F2α ethanolamide (PGF2αEA), inhibits adipogenesis, that is, the formation of mature adipocytes. We observed that adipocyte progenitor cells-preadipocytes-following treatment with PGF2αEA yielded larger pellet sizes. Thus, we hypothesized that PGF2αEA might augment preadipocyte proliferation. Cell viability MTT and crystal violet assays, cell counting, and 5-bromo-2'-deoxyuridine incorporation in cell proliferation ELISA analyses confirmed our prediction. Additionally, we discovered that PGF2αEA promotes cell cycle progression through suppression of the expression of cell cycle inhibitors, p21 and p27, as shown by flow cytometry and qPCR. Enticingly, concentrations of this compound that showed no visible effect on cell proliferation or basal transcriptional activity of peroxisome proliferator-activated receptor gamma could, in contrast, reverse the anti-proliferative and peroxisome proliferator-activated receptor gamma-transcription activating effects of rosiglitazone (Rosi). MTT and luciferase reporter examinations supported this finding. The PGF2αEA pharmaceutical analog, bimatoprost, was also investigated and showed very similar effects. Importantly, we suggest the implication of the mitogen-activated protein kinase pathway in these effects, as they were blocked by the selective mitogen-activated protein kinase kinase inhibitor, PD98059. We propose that PGF2αEA is a pivotal regulator of white adipose tissue plasticity, acting as a regulator of the preadipocyte pool in adipose tissue.
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Affiliation(s)
- Besma Boubertakh
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Département de médecine, Faculté de Médecine, Université Laval, Québec, Canada; Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Centre NUTRISS, Université Laval, Québec, Canada; Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada
| | - Olivier Courtemanche
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Département de médecine, Faculté de Médecine, Université Laval, Québec, Canada
| | - David Marsolais
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Département de médecine, Faculté de Médecine, Université Laval, Québec, Canada
| | - Vincenzo Di Marzo
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Département de médecine, Faculté de Médecine, Université Laval, Québec, Canada; Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Centre NUTRISS, Université Laval, Québec, Canada; Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada; École de Nutrition, Faculté des Sciences de l'Agriculture et de l'Alimentation (FSAA), Université Laval, Québec, Canada
| | - Cristoforo Silvestri
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Département de médecine, Faculté de Médecine, Université Laval, Québec, Canada; Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Centre NUTRISS, Université Laval, Québec, Canada; Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada.
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Rezvanian A, Esfandsar Z. Pyrazole-promoted synthesis of pyrrolo[3,4-c] quinoline-1,3-diones in a novel diketene-based reaction. Front Chem 2023; 11:1219986. [PMID: 37822773 PMCID: PMC10562593 DOI: 10.3389/fchem.2023.1219986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/08/2023] [Indexed: 10/13/2023] Open
Abstract
We describe the first classic example of green synthesis of pyrrolo[3,4-c]quinolones scaffolds by catalyst-free unusual reaction of diketene, isatin, and primary amines in ethanol in the presence of pyrazole as a promoter for 4 h. The whole structure of the new product was confirmed by X-ray analysis. The overall transformation involves the cleavage and generation of multiple carbon-nitrogen and carbon-carbon bonds. This report represents a simple and straightforward approach for the synthesis of pyrrolo[3,4-c]quinoline-1,3-diones, which has significant advantages like readily available precursors, non-use of toxic solvent, operational simplicity, mild conditions, good atom economy, and excellent yields; therefore it provides a green and sustainable strategy for access to a range of interesting N-containing heterocyclic compounds in medicinal and organic chemistry.
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Affiliation(s)
- Atieh Rezvanian
- Department of Organic Chemistry, Faculty of Chemistry, Alzahra University, Tehran, Iran
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3
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Jeong YE, Rajbhandari L, Kim BW, Venkatesan A, Hoke A. Downregulation of SF3B2 protects CNS neurons in models of multiple sclerosis. Ann Clin Transl Neurol 2023; 10:246-265. [PMID: 36574260 PMCID: PMC9930435 DOI: 10.1002/acn3.51717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Neurodegeneration induced by inflammatory stress in multiple sclerosis (MS) leads to long-term neurological disabilities that are not amenable to current immunomodulatory therapies. METHODS AND RESULTS Here, we report that neuronal downregulation of Splicing factor 3b subunit 2 (SF3B2), a component of U2 small nuclear ribonucleoprotein (snRNP), preserves retinal ganglion cell (RGC) survival and axonal integrity in experimental autoimmune encephalomyelitis (EAE)-induced mice. By employing an in vitro system recapitulating the inflammatory environment of MS lesion, we show that when SF3B2 levels are downregulated, cell viability and axon integrity are preserved in cortical neurons against inflammatory toxicity. Notably, knockdown of SF3B2 suppresses the expression of injury-response and necroptosis genes and prevents activation of Sterile Alpha and TIR Motif Containing 1 (Sarm1), a key enzyme that mediates programmed axon degeneration. INTERPRETATION Together, these findings suggest that the downregulation of SF3B2 is a novel potential therapeutic target to prevent secondary neurodegeneration in MS.
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Affiliation(s)
- Ye Eun Jeong
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Labchan Rajbhandari
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Byung Woo Kim
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Arun Venkatesan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Ahmet Hoke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
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4
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Yu L, Liu A, Zhang B, Kuang J, Guo X, Tian C, Lu Y. Dipolar coupling-based electron paramagnetic resonance method for protease enzymatic characterization and inhibitor screening. Chem Commun (Camb) 2021; 57:9602-9605. [PMID: 34546243 DOI: 10.1039/d1cc03301h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Herein, we report an EPR-based method for protease enzymatic characterization and inhibitor screening. This method utilizes dual paramagnetically-labeled probes consisting of a nitroxide spin probe and a Gd3+ ion flanking a peptide that could be specifically cleaved by protease caspase-3. Distance-dependent dipolar coupling between the two paramagnetic centers can be modulated by the protease cleavage activity, thus providing a straightforward and convenient method for protease activity detection using EPR spectroscopy under ambient conditions. Moreover, time-course monitoring of the protease-catalyzed cleavage reaction demonstrated that this EPR-based method could not only allow a direct quantitative enzymatic kinetic assessment, but also could be used for protease inhibitor screening, thus holding great potential in drug discovery studies.
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Affiliation(s)
- Lu Yu
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China.
| | - Aokun Liu
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China. .,The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Bingbo Zhang
- Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tongji University Cancer Center, The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Jian Kuang
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiaoqi Guo
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Changlin Tian
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China. .,The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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Poreba M, Szalek A, Kasperkiewicz P, Rut W, Salvesen GS, Drag M. Small Molecule Active Site Directed Tools for Studying Human Caspases. Chem Rev 2015; 115:12546-629. [PMID: 26551511 DOI: 10.1021/acs.chemrev.5b00434] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Caspases are proteases of clan CD and were described for the first time more than two decades ago. They play critical roles in the control of regulated cell death pathways including apoptosis and inflammation. Due to their involvement in the development of various diseases like cancer, neurodegenerative diseases, or autoimmune disorders, caspases have been intensively investigated as potential drug targets, both in academic and industrial laboratories. This review presents a thorough, deep, and systematic assessment of all technologies developed over the years for the investigation of caspase activity and specificity using substrates and inhibitors, as well as activity based probes, which in recent years have attracted considerable interest due to their usefulness in the investigation of biological functions of this family of enzymes.
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Affiliation(s)
- Marcin Poreba
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology , Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Aleksandra Szalek
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology , Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Paulina Kasperkiewicz
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology , Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Wioletta Rut
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology , Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Guy S Salvesen
- Program in Cell Death and Survival Networks, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California 92037, United States
| | - Marcin Drag
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Technology , Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
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Xia L, Lee YR. Efficient one-step synthesis of pyrrolo[3,4-c]quinoline-1,3-dione derivatives by organocatalytic cascade reactions of isatins and β-ketoamides. Org Biomol Chem 2013; 11:5254-63. [DOI: 10.1039/c3ob40791h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Samiulla DS, Naidu A, Rao GV, Ramachandra M. Discovery of indole tetrafluorophenoxymethylketone-based potent novel small molecule inhibitors of caspase-3. Org Med Chem Lett 2012; 2:27. [PMID: 22794498 PMCID: PMC3519673 DOI: 10.1186/2191-2858-2-27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/16/2012] [Indexed: 11/30/2022] Open
Abstract
Background Caspase-3 inhibition has been demonstrated to be therapeutically effective in moderating excessive programmed cell death. Interest in caspase-3 as a therapeutic target has led many to pursue the development of inhibitors. To date, only a few series of non-peptide inhibitors have been described, and these have limitations on their drug-like properties. Methods Here, we report the screening of 70 novel small molecules against the caspase-3 enzyme which belongs to four different series (indole fluoromethylketone, indole difluoro and tetrafluorophenoxymethylketone, and oxalamide). Selected molecules were subjected for counter-screening, cell-based, ADME/PK assays in order to understand the potency and drug-like properties. Results The screening yielded series of hits with IC50 values ranging from 0.11 to 10 μM with reasonable SAR, irreversible mode of inhibition, and reasonable selectivity against other proteases including caspase-1, cathepsin B and D, and thrombin. On the basis of in vitro profile, the selected molecules were evaluated for their drug-like properties. Among the compounds evaluated, compound 3D exhibited good solubility, low permeability, interaction with efflux pump, and low potential for CYP450 drug-drug interaction. After intravenous administration, compound 3D showed low clearance (588 ml/hr/kg), medium volume of distribution, and good oral bioavailability (90%). Conclusions These results support further advancement of compound 3D in different apoptotic models to develop as a new anti-apoptotic agent in relevant disease conditions.
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Affiliation(s)
- Dodheri Syed Samiulla
- DMPK Department, Aurigene Discovery Technologies Limited, Electronic City Phase 2, Hosur Road, Bangalore, 560100, India.
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8
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Hart MJ, Glicksman M, Liu M, Sharma MK, Cuny G, Galvan V. Development of a high-throughput screen targeting caspase-8-mediated cleavage of the amyloid precursor protein. Anal Biochem 2012; 421:467-76. [DOI: 10.1016/j.ab.2011.11.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 11/11/2011] [Accepted: 11/19/2011] [Indexed: 01/17/2023]
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Ayyash M, Tamimi H, Ashhab Y. Developing a powerful in silico tool for the discovery of novel caspase-3 substrates: a preliminary screening of the human proteome. BMC Bioinformatics 2012; 13:14. [PMID: 22269041 PMCID: PMC3324375 DOI: 10.1186/1471-2105-13-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 01/23/2012] [Indexed: 11/10/2022] Open
Abstract
Background Caspases are a family of cysteinyl proteases that regulate apoptosis and other biological processes. Caspase-3 is considered the central executioner member of this family with a wide range of substrates. Identification of caspase-3 cellular targets is crucial to gain further insights into the cellular mechanisms that have been implicated in various diseases including: cancer, neurodegenerative, and immunodeficiency diseases. To date, over 200 caspase-3 substrates have been identified experimentally. However, many are still awaiting discovery. Results Here, we describe a powerful bioinformatics tool that can predict the presence of caspase-3 cleavage sites in a given protein sequence using a Position-Specific Scoring Matrix (PSSM) approach. The present tool, which we call CAT3, was built using 227 confirmed caspase-3 substrates that were carefully extracted from the literature. Assessing prediction accuracy using 10 fold cross validation, our method shows AUC (area under the ROC curve) of 0.94, sensitivity of 88.83%, and specificity of 89.50%. The ability of CAT3 in predicting the precise cleavage site was demonstrated in comparison to existing state-of-the-art tools. In contrast to other tools which were trained on cleavage sites of various caspases as well as other similar proteases, CAT3 showed a significant decrease in the false positive rate. This cost effective and powerful feature makes CAT3 an ideal tool for high-throughput screening to identify novel caspase-3 substrates. The developed tool, CAT3, was used to screen 13,066 human proteins with assigned gene ontology terms. The analyses revealed the presence of many potential caspase-3 substrates that are not yet described. The majority of these proteins are involved in signal transduction, regulation of cell adhesion, cytoskeleton organization, integrity of the nucleus, and development of nerve cells. Conclusions CAT3 is a powerful tool that is a clear improvement over existing similar tools, especially in reducing the false positive rate. Human proteome screening, using CAT3, indicate the presence of a large number of possible caspase-3 substrates that exceed the anticipated figure. In addition to their involvement in various expected functions such as cytoskeleton organization, nuclear integrity and adhesion, a large number of the predicted substrates are remarkably associated with the development of nerve tissues.
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Affiliation(s)
- Muneef Ayyash
- Biotechnology Research Centre, Palestine Polytechnic University, Hebron, Palestine
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10
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Häcker HG, Sisay MT, Gütschow M. Allosteric modulation of caspases. Pharmacol Ther 2011; 132:180-95. [DOI: 10.1016/j.pharmthera.2011.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 12/19/2022]
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11
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Bauer A, Stockwell B. Neurobiological applications of small molecule screening. Chem Rev 2008; 108:1774-86. [PMID: 18447397 DOI: 10.1021/cr0782372] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Andras Bauer
- Columbia University, Department of Biological Sciences, 614 Fairchild Center, New York, New York 10027, USA
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12
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Establishment of the expression system for studying the function of active caspase-3 in zebrafish. Mol Biol Rep 2007; 36:405-13. [PMID: 18080784 DOI: 10.1007/s11033-007-9194-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 12/03/2007] [Indexed: 10/22/2022]
Abstract
Caspase-3, a key molecule in apoptosis, has been extensively studied in cell culture system; however, it has been less well characterized in vivo because certain mediators are required for the proteolytic activation of effector caspases, including caspase-3. In this study, various forms of caspase-3 with the C-terminal GFP tag were inserted into the pCS2+ plasmid, and the expression patterns of caspase-3 proteins were characterized in a zebrafish model system using microinjection of nucleic acids into zebrafish embryos. We have verified that active caspase-3 was generated by its autocatalytic activity under the condition of caspase-2 prodomain (C2P)-caspase-3-GFP overexpression, indicating that the C2P domain is crucial for the activation of caspase-3. We also confirmed that the C2P domain plays an important role in regulating the nuclear localization of the C2P-caspase-3 chimeric protein. We used this expression system to establish an animal model system suitable for the investigation of the functional characteristics of caspase-3 in vivo. Thus, our study provides a useful and specific tool for investigating the molecular mechanisms by which active caspase-3 regulates apoptosis during embryonic development.
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Dolle RE, Le Bourdonnec B, Goodman AJ, Morales GA, Salvino JM, Zhang W. Comprehensive survey of chemical libraries for drug discovery and chemical biology: 2006. ACTA ACUST UNITED AC 2007; 9:855-902. [PMID: 17877417 DOI: 10.1021/cc700111e] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roland E Dolle
- Adolor Corporation, 700 Pennsylvania Drive, Exton, Pennsylvania 19341, USA.
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Valencia CA, Bailey C, Liu R. Novel zebrafish caspase-3 substrates. Biochem Biophys Res Commun 2007; 361:311-6. [PMID: 17643392 DOI: 10.1016/j.bbrc.2007.06.173] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 06/28/2007] [Indexed: 11/28/2022]
Abstract
The zebrafish model has been widely used to investigate numerous signaling pathways in vertebrates, including programmed cell death. Although several zebrafish proteins homologous to mammalian caspases have been identified, our understanding of these zebrafish caspases is still limited. Recently, we identified a large number of natural caspase-3 substrates from the human proteome by using the mRNA-display selection method. Through comparative analysis, we found that the cleavage sites on some of these novel human caspase-3 substrates are highly conserved in their zebrafish orthologs. We report here the identification and characterization of 14 natural zebrafish caspase-3 substrates that have not yet been previously studied. The specific cleavage of these zebrafish proteins was compared with caspases from different species, and the protein fragments that contain the putative cleavage sites were mapped. The work described here could facilitate our understanding of the downstream signaling pathways that are mediated by caspase-3 in zebrafish.
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Affiliation(s)
- C Alexander Valencia
- School of Pharmacy and Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Shelat AA, Guy RK. The interdependence between screening methods and screening libraries. Curr Opin Chem Biol 2007; 11:244-51. [PMID: 17524728 DOI: 10.1016/j.cbpa.2007.05.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 05/03/2007] [Indexed: 11/22/2022]
Abstract
The most common methods for discovery of chemical compounds capable of manipulating biological function involves some form of screening. The success of such screens is highly dependent on the chemical materials - commonly referred to as libraries - that are assayed. Classic methods for the design of screening libraries have depended on knowledge of target structure and relevant pharmacophores for target focus, and on simple count-based measures to assess other properties. The recent proliferation of two novel screening paradigms, structure-based screening and high-content screening, prompts a profound rethink about the ideal composition of small-molecule screening libraries. We suggest that currently utilized libraries are not optimal for addressing new targets by high-throughput screening, or complex phenotypes by high-content screening.
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Affiliation(s)
- Anang A Shelat
- Department of Chemical Biology and Therapeutics, Saint Jude Children's Research Hospital, Memphis, TN 38103, USA
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Okun I, Malarchuk S, Dubrovskaya E, Khvat A, Tkachenko S, Kysil V, Kravchenko D, Ivachtchenko A. Screening for caspase-3 inhibitors: effect of a reducing agent on identified hit chemotypes. ACTA ACUST UNITED AC 2006; 11:694-703. [PMID: 16844966 DOI: 10.1177/1087057106289231] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
When studying cysteinyl proteases in general and caspases in particular, it is generally accepted that a reaction buffer must contain a reducing agent to prevent essential cysteinyl groups from spontaneous oxidation. Dithiothreitol (DTT) and beta-mercaptoethanol (beta-MCE) are 2 of the most broadly used reducing agents. While screening a library of small molecules against caspase-3, the authors have found that the nature of the reducing agent used, DTT or beta-MCE, dramatically affects screening results and leads to identification of nonoverlapping hits. Screening in DTT-containing buffer revealed few novel classes of small molecules that selectively and reversibly inhibit caspase-3 but failed to identify isatin sulfonamides recently found to be potent and selective caspase-3 inhibitors (false negatives). On the other hand, screening in the presence of beta-MCE failed to identify a series of hit compounds, 1,3-dioxo-2,3-dichloro-1H-pyrrolo[3,4-c]quinolines, discovered with DTT, whereas isatin sulphonamides in these conditions exhibited strong caspase-3 inhibition. In this work, the authors show that thiol-containing reducing agents can affect catalytic activity of caspase-3 and modify its thermostability in a redox-potential-independent manner. The authors speculate that the differential structural modifications of caspase-3 seen with different reducing agents represent structurally different caspase-3 conformations and are responsible for its differential sensitivity to small molecules of different chemotypes. Hence, selection of the reducing agent may dramatically affect the quality of high-throughput screening campaigns.
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Affiliation(s)
- Ilya Okun
- ChemDiv, Inc., San Diego, California 92121, USA.
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