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Ma H, Liang X, Li SS, Li W, Li TF. The role of anti-citrullinated protein antibody in pathogenesis of RA. Clin Exp Med 2024; 24:153. [PMID: 38972923 PMCID: PMC11228005 DOI: 10.1007/s10238-024-01359-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/21/2024] [Indexed: 07/09/2024]
Abstract
Rheumatoid arthritis (RA) is a common autoimmune rheumatic disease that causes chronic synovitis, bone erosion, and joint destruction. The autoantigens in RA include a wide array of posttranslational modified proteins, such as citrullinated proteins catalyzed by peptidyl arginine deiminase4a. Pathogenic anti-citrullinated protein antibodies (ACPAs) directed against a variety of citrullinated epitopes are abundant both in plasma and synovial fluid of RA patients. ACPAs play an important role in the onset and progression of RA. Intensive and extensive studies are being conducted to unveil the mechanisms of RA pathogenesis and evaluate the efficacy of some investigative drugs. In this review, we focus on the formation and pathogenic function of ACPAs.
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Affiliation(s)
- Hang Ma
- Department of Rheumatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Xu Liang
- Department of Rheumatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Shan-Shan Li
- Department of Rheumatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Wei Li
- Department of Rheumatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Tian-Fang Li
- Department of Rheumatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China.
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China.
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2
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Feng Q, Guo Q, Yu W, Li P, Yao C, Wang L, Song G. PADI4 negatively regulates RIG-I-mediated antiviral response through deacetylation of IFN-β promoter via HDAC1. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167092. [PMID: 38382623 DOI: 10.1016/j.bbadis.2024.167092] [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: 10/28/2023] [Revised: 02/03/2024] [Accepted: 02/16/2024] [Indexed: 02/23/2024]
Abstract
The production of type I interferon (IFN) is precisely modulated by host to protect against viral infection efficiently without obvious immune disorders. Elucidating the tight control towards type I IFN production would be helpful to get insight into natural immunity and inflammatory diseases. As yet, however, the mechanisms that regulate IFN-β production, especially the epigenetic regulatory mechanisms, remain poorly explored. This study elucidated the potential function of Peptidylarginine deiminases (PADIs)-mediated citrullination in innate immunity. We identified PADI4, a PADIs family member that can act as an epigenetic coactivator, could repress IFN-β production upon RNA virus infection. Detailed experiments showed that PADI4 deficiency increased IFN-β production and promoted antiviral immune activities against RNA viruses. Mechanistically, the increased PADI4 following viral infection translocated to nucleus and recruited HDAC1 upon binding to Ifnb1 promoter, which then led to the deacetylation of histone H3 and histone H4 for repressing Ifnb1 transcription. Taken together, we identify a novel non-classical role for PADI4 in the regulation of IFN-β production, suggesting its potential as treatment target in inflammatory or autoimmune diseases.
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Affiliation(s)
- Qingwen Feng
- School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250000, Shandong, China
| | - Qingwei Guo
- Department of Hematology, Children's Hospital Affiliated to Shandong University, Jinan 250000, Shandong, China
| | - Weijie Yu
- Qingdao Institute for Food and Drug Control, Qingdao 266071, Shandong, China
| | - Peng Li
- School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250000, Shandong, China
| | - Chengfang Yao
- School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250000, Shandong, China
| | - Lin Wang
- Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Key lab for Biotech-Drugs of National Health Commission, Key Lab for Rare & Uncommon Diseases of Shandong Province, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250000, Shandong, China
| | - Guanhua Song
- Shandong Provincial Key Laboratory for Rheumatic Disease and Translational Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan 250000, China; Department of Immunology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250000, Shandong, China.
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3
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Dejbakht M, Akhzari M, Jalili S, Faraji F, Barazesh M. Multiple Sclerosis: New Insights into Molecular Pathogenesis and Novel Platforms for Disease Treatment. Curr Drug Res Rev 2024; 16:175-197. [PMID: 37724675 DOI: 10.2174/2589977516666230915103730] [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: 01/08/2023] [Revised: 06/23/2023] [Accepted: 07/03/2023] [Indexed: 09/21/2023]
Abstract
BACKGROUND Multiple sclerosis (MS), a chronic inflammatory disorder, affects the central nervous system via myelin degradation. The cause of MS is not fully known, but during recent years, our knowledge has deepened significantly regarding the different aspects of MS, including etiology, molecular pathophysiology, diagnosis and therapeutic options. Myelin basic protein (MBP) is the main myelin protein that accounts for maintaining the stability of the myelin sheath. Recent evidence has revealed that MBP citrullination or deamination, which is catalyzed by Ca2+ dependent peptidyl arginine deiminase (PAD) enzyme leads to the reduction of positive charge, and subsequently proteolytic cleavage of MBP. The overexpression of PAD2 in the brains of MS patients plays an essential role in new epitope formation and progression of the autoimmune disorder. Some drugs have recently entered phase III clinical trials with promising efficacy and will probably obtain approval in the near future. As different therapeutic platforms develop, finding an optimal treatment for each individual patient will be more challenging. AIMS This review provides a comprehensive insight into MS with a focus on its pathogenesis and recent advances in diagnostic methods and its present and upcoming treatment modalities. CONCLUSION MS therapy alters quickly as research findings and therapeutic options surrounding MS expand. McDonald's guidelines have created different criteria for MS diagnosis. In recent years, ever-growing interest in the development of PAD inhibitors has led to the generation of many reversible and irreversible PAD inhibitors against the disease with satisfactory therapeutic outcomes.
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Affiliation(s)
- Majid Dejbakht
- Department of Cellular and Molecular Research Center, Gerash University of Medical Sciences, Gerash, Iran
| | - Morteza Akhzari
- School of Nursing, Larestan University of Medical Sciences, Larestan, Iran
| | - Sajad Jalili
- Department of Orthopedics, School of Medicine, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, Iran
| | - Fouziyeh Faraji
- Department of Cellular and Molecular Research Center, Gerash University of Medical Sciences, Gerash, Iran
| | - Mahdi Barazesh
- Department of Biotechnology, Cellular and Molecular Research Center, School of Paramedical, Gerash University of Medical Sciences, Gerash, Iran
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Nava-Quiroz KJ, López-Flores LA, Pérez-Rubio G, Rojas-Serrano J, Falfán-Valencia R. Peptidyl Arginine Deiminases in Chronic Diseases: A Focus on Rheumatoid Arthritis and Interstitial Lung Disease. Cells 2023; 12:2829. [PMID: 38132149 PMCID: PMC10741699 DOI: 10.3390/cells12242829] [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: 10/14/2023] [Revised: 12/03/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023] Open
Abstract
Protein citrullination is accomplished by a broad enzyme family named Peptidyl Arginine Deiminases (PADs), which makes this post-translational modification in many proteins that perform physiological and pathologic mechanisms in the body. Due to these modifications, citrullination has become a significant topic in the study of pathological processes. It has been related to some chronic and autoimmune diseases, including rheumatoid arthritis (RA), interstitial lung diseases (ILD), multiple sclerosis (MS), and certain types of cancer, among others. Antibody production against different targets, including filaggrin, vimentin, and collagen, results in an immune response if they are citrullinated, which triggers a continuous inflammatory process characteristic of autoimmune and certain chronic diseases. PAD coding genes (PADI1 to PADI4 and PADI6) harbor variations that can be important in these enzymes' folding, activity, function, and half-life. However, few studies have considered these genetic factors in the context of chronic diseases. Exploring PAD pathways and their role in autoimmune and chronic diseases is a major topic in developing new pharmacological targets and valuable biomarkers to improve diagnosis and prevention. The present review addresses and highlights genetic, molecular, biochemical, and physiopathological factors where PAD enzymes perform a major role in autoimmune and chronic diseases.
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Affiliation(s)
- Karol J. Nava-Quiroz
- HLA Laboratory, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Tlalpan, Mexico City 14080, Mexico; (K.J.N.-Q.); (G.P.-R.)
- Programa de Doctorado en Ciencias Médicas Odontológicas y de la Salud, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico
| | - Luis A. López-Flores
- HLA Laboratory, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Tlalpan, Mexico City 14080, Mexico; (K.J.N.-Q.); (G.P.-R.)
- Programa de Doctorado en Ciencias Médicas Odontológicas y de la Salud, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico
| | - Gloria Pérez-Rubio
- HLA Laboratory, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Tlalpan, Mexico City 14080, Mexico; (K.J.N.-Q.); (G.P.-R.)
| | - Jorge Rojas-Serrano
- Rheumatology Clinic, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Tlalpan, Mexico City 14080, Mexico
| | - Ramcés Falfán-Valencia
- HLA Laboratory, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Tlalpan, Mexico City 14080, Mexico; (K.J.N.-Q.); (G.P.-R.)
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5
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Zainal Fithri HH, Ibrahim Z, Ali EZ. Impact of GSK199 and GSK106 binding on protein arginine deiminase IV stability and flexibility: A computational approach. Comput Biol Chem 2023; 107:107962. [PMID: 37847978 DOI: 10.1016/j.compbiolchem.2023.107962] [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: 06/15/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Protein arginine deiminase IV (PAD4) is a potential target for diseases including rheumatoid arthritis and cancers. Currently, GSK199 is a potent, selective yet reversible PAD4 inhibitor. Its derivative, GSK106, on the other hand, was reported as an inactive compound when tested against PAD4 assay. Although they had similar skeleton, their impact towards PAD4 structural and flexibility is unknown. In order to fill the research gap, the impact of GSK199 and GSK106 binding towards PAD4 stability and flexibility is investigated via a combination of computational methods. Molecular docking indicates that GSK199 and GSK106 are capable to bind at PAD4 pocket by using its back door with -10.6 kcal/mol and -9.6 kcal/mol, respectively. The simulations of both complexes were stable throughout 100 ns. The structure of PAD4 exhibited a tighter packing in the presence of GSK106 compared to GSK199. The RMSF analysis demonstrates significant changes between the PAD4-GSK199 and PAD4-GSK106 simulations in the regions containing residues 136, 160, 220, 438, and 606. The Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) analysis shows a marked difference in binding free energies, with -11.339 kcal/mol for the PAD4-GSK199 complex and 1.063 kcal/mol for the PAD4-GSK106 complex. The hydrogen bond analysis revealed that the GSK199 and GSK106 binding to PAD4 are assisted by six hydrogen bonds and three hydrogen bonds, respectively. The visualisation of the MD simulations revealed that GSK199 remained in the PAD4 pocket, whereas GSK106 shifted away from the catalytic site. Meanwhile, molecular dockings of benzoyl arginine amide (BAEE) substrate have shown that BAEE is able to bind to PAD4 catalytic site when GSK106 was present but not when GSK199 occupied the site. Overall, combination of computational approaches successfully described the behaviour of binding pocket of PAD4 structure in the presence of the active and inactive compounds.
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Affiliation(s)
- Helmi Husaini Zainal Fithri
- Department of Pharmaceutical Chemistry, Kulliyyah of Pharmacy, International Islamic University Malaysia, Indera Mahkota, 25200 Kuantan, Pahang, Malaysia
| | - Zalikha Ibrahim
- Department of Pharmaceutical Chemistry, Kulliyyah of Pharmacy, International Islamic University Malaysia, Indera Mahkota, 25200 Kuantan, Pahang, Malaysia; Drug Discovery and Synthetic Chemistry Research Group, Kulliyyah of Pharmacy, International Islamic University Malaysia, Indera Mahkota, 25200 Kuantan, Pahang, Malaysia.
| | - Ernie Zuraida Ali
- Inborn Error of Metabolism and Genetic Unit, Nutrition, Metabolism and Cardiovascular Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, Section U13 Setia Alam, 40170 Shah Alam, Selangor, Malaysia
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6
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Barasa L, Thompson PR. Protein citrullination: inhibition, identification and insertion. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220240. [PMID: 37778377 PMCID: PMC10542963 DOI: 10.1098/rstb.2022.0240] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/26/2023] [Indexed: 10/03/2023] Open
Abstract
Protein citrullination is a post-translational modification (PTM) that is catalysed by the protein arginine deiminase (PAD) family of enzymes. This PTM involves the transformation of an arginine residue into citrulline. Protein citrullination is associated with several physiological processes, including the epigenetic regulation of gene expression, neutrophil extracellular trap formation and DNA damage-induced apoptosis. Aberrant protein citrullination is relevant to several autoimmune and neurodegenerative diseases and certain forms of cancer. PAD inhibitors have shown remarkable efficacy in a range of diseases including rheumatoid arthritis (RA), lupus, atherosclerosis and ulcerative colitis. In RA, anti-citrullinated protein antibodies can be detected prior to disease onset and are thus a valuable diagnostic tool for RA. Notably, citrullinated proteins may serve more generally as biomarkers of specific disease states; however, the identification of citrullinated protein residues remains challenging owing to the small 1 Da mass change that occurs upon citrullination. Herein, we highlight the progress made so far in the development of pan-PAD and isozyme selective inhibitors as well as the identification of citrullinated proteins and the site-specific incorporation of citrulline into proteins. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.
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Affiliation(s)
- Leonard Barasa
- Program in Chemical Biology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Paul R. Thompson
- Program in Chemical Biology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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Roy A, Niharika, Chakraborty S, Mishra J, Singh SP, Patra SK. Mechanistic aspects of reversible methylation modifications of arginine and lysine of nuclear histones and their roles in human colon cancer. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 197:261-302. [PMID: 37019596 DOI: 10.1016/bs.pmbts.2023.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Developmental proceedings and maintenance of cellular homeostasis are regulated by the precise orchestration of a series of epigenetic events that eventually control gene expression. DNA methylation and post-translational modifications (PTMs) of histones are well-characterized epigenetic events responsible for fine-tuning gene expression. PTMs of histones bear molecular logic of gene expression at chromosomal territory and have become a fascinating field of epigenetics. Nowadays, reversible methylation on histone arginine and lysine is gaining increasing attention as a significant PTM related to reorganizing local nucleosomal structure, chromatin dynamics, and transcriptional regulation. It is now well-accepted and reported that histone marks play crucial roles in colon cancer initiation and progression by encouraging abnormal epigenomic reprogramming. It is becoming increasingly clear that multiple PTM marks at the N-terminal tails of the core histones cross-talk with one another to intricately regulate DNA-templated biological processes such as replication, transcription, recombination, and damage repair in several malignancies, including colon cancer. These functional cross-talks provide an additional layer of message, which spatiotemporally fine-tunes the overall gene expression regulation. Nowadays, it is evident that several PTMs instigate colon cancer development. How colon cancer-specific PTM patterns or codes are generated and how they affect downstream molecular events are uncovered to some extent. Future studies would address more about epigenetic communication, and the relationship between histone modification marks to define cellular functions in depth. This chapter will comprehensively highlight the importance of histone arginine and lysine-based methylation modifications and their functional cross-talk with other histone marks from the perspective of colon cancer development.
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8
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Zhu D, Lu Y, Wang Y, Wang Y. PAD4 and Its Inhibitors in Cancer Progression and Prognosis. Pharmaceutics 2022; 14:2414. [PMID: 36365233 PMCID: PMC9699117 DOI: 10.3390/pharmaceutics14112414] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/28/2022] [Accepted: 11/06/2022] [Indexed: 07/24/2023] Open
Abstract
The systemic spread of malignancies and the risk of cancer-associated thrombosis are major clinical challenges in cancer therapy worldwide. As an important post-translational modification enzyme, peptidyl arginine deiminase 4 (PAD4) could mediate the citrullination of protein in different components (including nucleus and cytoplasm, etc.) of a variety of cells (tumor cells, neutrophils, macrophages, etc.), thus participating in gene regulation, neutrophil extracellular trap (NET) and macrophage extracellular trap (MET). Thereby, PAD4 plays an important role in enhancing the growth of primary tumors and facilitating the distant metastasis of cancer cells. In addition, it is related to the formation of cancer-associated thrombosis. Therefore, the development of PAD4-specific inhibitors may be a promising strategy for treating cancer, and it may improve patient prognosis. In this review, we describe PAD4 involvement in gene regulation, protein citrullination, and NET formation. We also discuss its potential role in cancer and cancer-associated thrombosis, and we summarize the development and application of PAD4 inhibitors.
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Affiliation(s)
- Di Zhu
- Department of Medicinal Chemistry, College of Pharmaceutical Sciences of Capital Medical University, Beijing 100069, China
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, Beijing 100069, China
| | - Yu Lu
- Department of Medicinal Chemistry, College of Pharmaceutical Sciences of Capital Medical University, Beijing 100069, China
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, Beijing 100069, China
| | - Yanming Wang
- School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yuji Wang
- Department of Medicinal Chemistry, College of Pharmaceutical Sciences of Capital Medical University, Beijing 100069, China
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, Beijing 100069, China
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9
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Cicek E, Monard G, Sungur FA. Molecular Mechanism of Protein Arginine Deiminase 2: A Study Involving Multiple Microsecond Long Molecular Dynamics Simulations. Biochemistry 2022; 61:1286-1297. [PMID: 35737372 PMCID: PMC9260958 DOI: 10.1021/acs.biochem.2c00158] [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] [Indexed: 11/29/2022]
Abstract
Peptidylarginine deiminase 2 (PAD2) is a Ca2+-dependent enzyme that catalyzes the conversion of protein arginine residues to citrulline. This kind of structural modification in histone molecules may affect gene regulation, leading to effects that may trigger several diseases, including breast cancer, which makes PAD2 an attractive target for anticancer drug development. To design new effective inhibitors to control activation of PAD2, improving our understanding of the molecular mechanisms of PAD2 using up-to-date computational techniques is essential. We have designed five different PAD2-substrate complex systems based on varying protonation states of the active site residues. To search the conformational space broadly, multiple independent molecular dynamics simulations of the complexes have been performed. In total, 50 replica simulations have been performed, each of 1 μs, yielding a total simulation time of 50 μs. Our findings identify that the protonation states of Cys647, Asp473, and His471 are critical for the binding and localization of the N-α-benzoyl-l-arginine ethyl ester substrate within the active site. A novel mechanism for enzyme activation is proposed according to near attack conformers. This represents an important step in understanding the mechanism of citrullination and developing PAD2-inhibiting drugs for the treatment of breast cancer.
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Affiliation(s)
- Erdem Cicek
- Informatics Institute, Computational Science and Engineering, Istanbul Technical University, TR-34469 Istanbul, Turkey
| | - Gerald Monard
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France
| | - Fethiye Aylin Sungur
- Informatics Institute, Computational Science and Engineering, Istanbul Technical University, TR-34469 Istanbul, Turkey
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10
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Citrullination in the pathology of inflammatory and autoimmune disorders: recent advances and future perspectives. Cell Mol Life Sci 2022; 79:94. [PMID: 35079870 PMCID: PMC8788905 DOI: 10.1007/s00018-022-04126-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/29/2021] [Accepted: 01/03/2022] [Indexed: 02/06/2023]
Abstract
Numerous
post-translational modifications (PTMs) govern the collective metabolism of a cell through altering the structure and functions of proteins. The action of the most prevalent PTMs, encompassing phosphorylation, methylation, acylations, ubiquitination and glycosylation is well documented. A less explored protein PTM, conversion of peptidylarginine to citrulline, is the subject of this review. The process of citrullination is catalysed by peptidylarginine deiminases (PADs), a family of conserved enzymes expressed in a variety of human tissues. Accumulating evidence suggest that citrullination plays a significant role in regulating cellular metabolism and gene expression by affecting a multitude of pathways and modulating the chromatin status. Here, we will discuss the biochemical nature of arginine citrullination, the enzymatic machinery behind it and also provide information on the pathological consequences of citrullination in the development of inflammatory diseases (rheumatoid arthritis, multiple sclerosis, psoriasis, systemic lupus erythematosus, periodontitis and COVID-19), cancer and thromboembolism. Finally, developments on inhibitors against protein citrullination and recent clinical trials providing a promising therapeutic approach to inflammatory disease by targeting citrullination are discussed.
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Neira JL, Araujo-Abad S, Cámara-Artigas A, Rizzuti B, Abian O, Giudici AM, Velazquez-Campoy A, de Juan Romero C. Biochemical and biophysical characterization of PADI4 supports its involvement in cancer. Arch Biochem Biophys 2022; 717:109125. [DOI: 10.1016/j.abb.2022.109125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 12/12/2022]
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12
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Rechiche O, Lee TV, Lott JS. Structural characterization of human peptidyl-arginine deiminase type III by X-ray crystallography. Acta Crystallogr F Struct Biol Commun 2021; 77:334-340. [PMID: 34605437 PMCID: PMC8488854 DOI: 10.1107/s2053230x21009195] [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: 03/04/2021] [Accepted: 09/04/2021] [Indexed: 11/10/2022] Open
Abstract
The Ca2+-dependent enzyme peptidyl-arginine deiminase type III (PAD3) catalyses the deimination of arginine residues to form citrulline residues in proteins such as keratin, filaggrin and trichohyalin. This is an important post-translation modification that is required for normal hair and skin formation in follicles and keratocytes. The structure of apo human PAD3 was determined by X-ray crystallography to a resolution of 2.8 Å. The structure of PAD3 revealed a similar overall architecture to other PAD isoforms: the N-terminal and middle domains of PAD3 show sequence and structural variety, whereas the sequence and structure of the C-terminal catalytic domain is highly conserved. Structural analysis indicates that PAD3 is a dimer in solution, as is also the case for the PAD2 and PAD4 isoforms but not the PAD1 isoform.
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Affiliation(s)
- Othman Rechiche
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, Althouse Laboratory, Science Drive, State College, PA 16801, USA
| | - T. Verne Lee
- School of Biological Sciences, The University of Auckland, 3a Symonds Street, Auckland 1142, New Zealand
| | - J. Shaun Lott
- School of Biological Sciences, The University of Auckland, 3a Symonds Street, Auckland 1142, New Zealand
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Funabashi K, Sawata M, Nagai A, Akimoto M, Mashimo R, Takahara H, Kizawa K, Thompson PR, Ite K, Kitanishi K, Unno M. Structures of human peptidylarginine deiminase type III provide insights into substrate recognition and inhibitor design. Arch Biochem Biophys 2021; 708:108911. [PMID: 33971157 DOI: 10.1016/j.abb.2021.108911] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 11/29/2022]
Abstract
Peptidylarginine deiminase type III (PAD3) is an isozyme belonging to the PAD enzyme family that converts arginine to citrulline residue(s) within proteins. PAD3 is expressed in most differentiated keratinocytes of the epidermis and hair follicles, while S100A3, trichohyalin, and filaggrin are its principal substrates. In this study, the X-ray crystal structures of PAD3 in six states, including its complex with the PAD inhibitor Cl-amidine, were determined. This structural analysis identified a large space around Gly374 in the PAD3-Ca2+-Cl-amidine complex, which may be used to develop novel PAD3-selective inhibitors. In addition, similarities between PAD3 and PAD4 were found based on the investigation of PAD4 reactivity with S100A3 in vitro. A comparison of the structures of PAD1, PAD2, PAD3, and PAD4 implied that the flexibility of the structures around the active site may lead to different substrate selectivity among these PAD isozymes.
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Affiliation(s)
- Kazumasa Funabashi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
| | - Mizuki Sawata
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
| | - Anna Nagai
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan
| | - Megumi Akimoto
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan
| | - Ryutaro Mashimo
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan
| | - Hidenari Takahara
- Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan; College of Agriculture, Ibaraki University, Ami Inashiki, Japan
| | - Kenji Kizawa
- Kao Corporation, Biological Science Research Laboratory, Odawara, Japan
| | - Paul R Thompson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Kenji Ite
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan
| | - Kenichi Kitanishi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Tokyo University of Science, Faculty of Science Division I, Tokyo, Japan
| | - Masaki Unno
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan; Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai Naka, Japan.
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14
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Deng J, Cui Q. Reverse Protonation of Buried Ion-Pairs in Staphylococcal Nuclease Mutants. J Chem Theory Comput 2021; 17:4550-4563. [PMID: 34143626 DOI: 10.1021/acs.jctc.1c00355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Although buried titratable residues in protein cavities are often of major functional importance, it is generally challenging to understand their properties such as the ionization state and factors of stabilization based on experimental studies alone. A specific set of examples involve buried Glu-Lys pairs in a series of variants of Staphylococcal nuclease, for which recent structural and thermodynamic studies appeared to suggest that both the stability and the ionization state of the buried Glu-Lys pair are sensitive to its orientation (i.e., Glu23-Lys36 vs Lys23-Glu36). To further clarify the situation, especially ionization states of the buried Glu-Lys pairs, we have conducted extensive molecular dynamics simulations and free energy computations. Microsecond molecular dynamics simulations show that the hydration level of the cavity depends on the orientation of the buried ion-pair therein as well as its ionization state; free energy simulations recapitulate the relative stability of Glu23-Lys36 (EK) vs Lys23-Glu36 (KE) mutants measured experimentally, although the difference is similar in magnitude regardless of the ionization state of the Glu-Lys pair. A complementary set of free energy simulations strongly suggests that, in contrast to the original suggestion in the experimental analysis, the Glu and Lys residues prefer to adopt their charge-neutral rather than the ionized states. This result is consistent with the low dielectric constant computed for water in the cavity, which makes it difficult for the protein cavity to stabilize a pair of charged Glu-Lys residues, even with water penetration. The current study highlights the role of free energy simulations in understanding the ionization state of buried titratable residues and the relevant energetic contributions, forming the basis for the rational design of buried charge networks in proteins.
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Affiliation(s)
- Jiahua Deng
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Qiang Cui
- Departments of Chemistry, Physics, and Biomedical Engineering, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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15
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Liu X, Arfman T, Wichapong K, Reutelingsperger CPM, Voorberg J, Nicolaes GAF. PAD4 takes charge during neutrophil activation: Impact of PAD4 mediated NET formation on immune-mediated disease. J Thromb Haemost 2021; 19:1607-1617. [PMID: 33773016 PMCID: PMC8360066 DOI: 10.1111/jth.15313] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Peptidyl arginine deiminase 4 (PAD4) is an enzyme that converts arginine into citrulline. PAD4 is expressed in neutrophils that, when activated, can drive the formation of neutrophil extracellular traps (NETs). Uncontrolled activation of PAD4 and subsequent citrullination of proteins is increasingly recognized as a driver of (auto)immune diseases. Currently, our understanding of PAD4 structure-function relationships and activity control in vivo is incomplete. AIMS To provide the current state-of-the-art on PAD4 structure-activity relationships and involvement of PAD4 in autoimmune disorders as well as in thrombo-inflammatory disease. MATERIALS & METHODS Literature review and molecular modelling Results: In this review, we used molecular modelling to generate a three-dimensional structure of the complete PAD4 molecule. Using our model, we discuss the catalytic conversion of the arginine substrate to citrulline. Besides mechanistic insight into PAD4 function, we give an overview of biological functions of PAD4 and mechanisms that influence its activation. In addition, we discuss the crucial role of PAD4-mediated citrullination of histones during the formation of NETs. Subsequently, we focus on the role of PAD4-mediated NET formation and its role in pathogenesis of rheumatoid arthritis, sepsis and (immune-)thrombosis. Finally, we summarize current efforts to design different classes of PAD4 inhibitors that are being developed for improved treatment of autoimmune disorders as well as thrombo-inflammatory disease. DISCUSSION Advances in PAD4 structure-function are still necessary to gain a complete insight in mechanisms that control PAD4 activity in vivo. The involvement of PAD4 in several diseases signifies the need for a PAD4 inhibitor. Although progress has been made to produce an isotype specific and potent PAD4 inhibitor, currently no PAD4 inhibitor is ready for clinical use. CONCLUSION More research into PAD4 structure and function and into the regulation of its activity is required for the development of PAD4 specific inhibitors that may prove vital to combat and prevent autoimmune disorders and (thrombo)inflammatory disease.
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Affiliation(s)
- Xiaosong Liu
- Department of BiochemistryCardiovascular Research Institute Maastricht (CARIM), Maastricht UniversityMaastrichtThe Netherlands
| | - Tom Arfman
- Department of Molecular and Cellular HaemostasisSanquin Research and Landsteiner LaboratoryAmsterdamThe Netherlands
| | - Kanin Wichapong
- Department of BiochemistryCardiovascular Research Institute Maastricht (CARIM), Maastricht UniversityMaastrichtThe Netherlands
| | - Chris P. M. Reutelingsperger
- Department of BiochemistryCardiovascular Research Institute Maastricht (CARIM), Maastricht UniversityMaastrichtThe Netherlands
| | - Jan Voorberg
- Department of Molecular and Cellular HaemostasisSanquin Research and Landsteiner LaboratoryAmsterdamThe Netherlands
| | - Gerry A. F. Nicolaes
- Department of BiochemistryCardiovascular Research Institute Maastricht (CARIM), Maastricht UniversityMaastrichtThe Netherlands
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16
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Loring HS, Czech VL, Icso JD, O'Connor L, Parelkar SS, Byrne AB, Thompson PR. A phase transition enhances the catalytic activity of SARM1, an NAD + glycohydrolase involved in neurodegeneration. eLife 2021; 10:66694. [PMID: 34184985 PMCID: PMC8266388 DOI: 10.7554/elife.66694] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/06/2021] [Indexed: 12/30/2022] Open
Abstract
Sterile alpha and toll/interleukin receptor (TIR) motif–containing protein 1 (SARM1) is a neuronally expressed NAD+ glycohydrolase whose activity is increased in response to stress. NAD+ depletion triggers axonal degeneration, which is a characteristic feature of neurological diseases. Notably, loss of SARM1 is protective in murine models of peripheral neuropathy and traumatic brain injury. Herein, we report that citrate induces a phase transition that enhances SARM1 activity by ~2000-fold. This phase transition can be disrupted by mutating a residue involved in multimerization, G601P. This mutation also disrupts puncta formation in cells. We further show that citrate induces axonal degeneration in C. elegans that is dependent on the C. elegans orthologue of SARM1 (TIR–1). Notably, citrate induces the formation of larger puncta indicating that TIR–1/SARM1 multimerization is essential for degeneration in vivo. These findings provide critical insights into SARM1 biology with important implications for the discovery of novel SARM1-targeted therapeutics.
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Affiliation(s)
- Heather S Loring
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, United States.,Program in Chemical Biology, UMass Medical School, Worcester, United States
| | - Victoria L Czech
- Department of Neurobiology, UMass Medical School, Worcester, United States
| | - Janneke D Icso
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, United States.,Program in Chemical Biology, UMass Medical School, Worcester, United States
| | - Lauren O'Connor
- Department of Neurobiology, UMass Medical School, Worcester, United States
| | - Sangram S Parelkar
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, United States.,Program in Chemical Biology, UMass Medical School, Worcester, United States
| | - Alexandra B Byrne
- Department of Neurobiology, UMass Medical School, Worcester, United States
| | - Paul R Thompson
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, United States.,Program in Chemical Biology, UMass Medical School, Worcester, United States
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17
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Discovery of new inhibitor for the protein arginine deiminase type 4 (PAD4) by rational design of α-enolase-derived peptides. Comput Biol Chem 2021; 92:107487. [PMID: 33957477 DOI: 10.1016/j.compbiolchem.2021.107487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/21/2021] [Indexed: 12/13/2022]
Abstract
Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting about 0.24 % of the world population. Protein arginine deiminase type 4 (PAD4) is believed to be responsible for the occurrence of RA by catalyzing citrullination of proteins. The citrullinated proteins act as autoantigens by stimulating an immune response. Citrullinated α-enolase has been identified as one of the autoantigens for RA. Hence, α-enolase serves as a suitable template for design of potential peptide inhibitors against PAD4. The binding affinity of α-enolase-derived peptides and PAD4 was virtually determined using PatchDock and HADDOCK docking programs. Synthesis of the designed peptides was performed using a solid phase peptide synthesis method. The inhibitory potential of each peptide was determined experimentally by PAD4 inhibition assay and IC50 measurement. PAD4 assay data show that the N-P2 peptide is the most favourable substrate among all peptides. Further modification of N-P2 by changing the Arg residue to canavanine [P2 (Cav)] rendered it an inhibitor against PAD4 by reducing the PAD4 activity to 35 % with IC50 1.39 mM. We conclude that P2 (Cav) is a potential inhibitor against PAD4 and can serve as a starting point for the development of even more potent inhibitors.
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18
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Inverse Solvent Isotope Effects in Enzyme-Catalyzed Reactions. Molecules 2020; 25:molecules25081933. [PMID: 32326332 PMCID: PMC7221790 DOI: 10.3390/molecules25081933] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 11/17/2022] Open
Abstract
Solvent isotope effects have long been used as a mechanistic tool for determining enzyme mechanisms. Most commonly, macroscopic rate constants such as kcat and kcat/Km are found to decrease when the reaction is performed in D2O for a variety of reasons including the transfer of protons. Under certain circumstances, these constants are found to increase, in what is termed an inverse solvent kinetic isotope effect (SKIE), which can be a diagnostic mechanistic feature. Generally, these phenomena can be attributed to an inverse solvent equilibrium isotope effect on a rapid equilibrium preceding the rate-limiting step(s). This review surveys inverse SKIEs in enzyme-catalyzed reactions by assessing their underlying origins in common mechanistic themes. Case studies for each category are presented, and the mechanistic implications are put into context. It is hoped that readers may find the illustrative examples valuable in planning and interpreting solvent isotope effect experiments.
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19
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Alghamdi M, Al Ghamdi KA, Khan RH, Uversky VN, Redwan EM. An interplay of structure and intrinsic disorder in the functionality of peptidylarginine deiminases, a family of key autoimmunity-related enzymes. Cell Mol Life Sci 2019; 76:4635-4662. [PMID: 31342121 PMCID: PMC11105357 DOI: 10.1007/s00018-019-03237-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 12/21/2022]
Abstract
Citrullination is a post-translation modification of proteins, where the proteinaceous arginine residues are converted to non-coded citrulline residues. The immune tolerance to such citrullinated protein can be lost, leading to inflammatory and autoimmune diseases. Citrullination is a chemical reaction mediated by peptidylarginine deiminase enzymes (PADs), which are a family of calcium-dependent cysteine hydrolase enzymes that includes five isotypes: PAD1, PAD2, PAD3, PAD4, and PAD6. Each PAD has specific substrates and tissue distribution, where it modifies the arginine to produce a citrullinated protein with altered structure and function. All mammalian PADs have a sequence similarity of about 70-95%, whereas in humans, they are 50-55% homologous in their structure and amino acid sequences. Being calcium-dependent hydrolases, PADs are inactive under the physiological level of calcium, but could be activated due to distortions in calcium homeostasis, or when the cellular calcium levels are increased. In this article, we analyze some of the currently available data on the structural properties of human PADs, the mechanisms of their calcium-induced activation, and show that these proteins contain functionally important regions of intrinsic disorder. Citrullination represents an important trigger of multiple physiological and pathological processes, and as a result, PADs are recognized to play a number of important roles in autoimmune diseases, cancer, and neurodegeneration. Therefore, we also review the current state of the art in the development of PAD inhibitors with good potency and selectivity.
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Affiliation(s)
- Mohammed Alghamdi
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
- Laboratory Department, University Medical Services Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21589, Saudi Arabia
| | - Khaled A Al Ghamdi
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
| | - Rizwan H Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, UP, India
| | - Vladimir N Uversky
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia.
- Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, 7 Institutskaya Str., 142290, Pushchino, Moscow region, Russia.
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Elrashdy M Redwan
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia.
- Therapeutic and Protective Proteins Laboratory, Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications, New Borg EL-Arab, Alexandria, 21934, Egypt.
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20
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Mondal S, Thompson PR. Protein Arginine Deiminases (PADs): Biochemistry and Chemical Biology of Protein Citrullination. Acc Chem Res 2019; 52:818-832. [PMID: 30844238 DOI: 10.1021/acs.accounts.9b00024] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Proteins are well-known to undergo a variety of post-translational modifications (PTMs). One such PTM is citrullination, an arginine modification that is catalyzed by a group of hydrolases called protein arginine deiminases (PADs). Hundreds of proteins are known to be citrullinated and hypercitrullination is associated with autoimmune diseases including rheumatoid arthritis (RA), lupus, ulcerative colitis (UC), Alzheimer's disease, multiple sclerosis (MS), and certain cancers. In this Account, we summarize our efforts to understand the structure and mechanism of the PADs and to develop small molecule chemical probes of protein citrullination. PAD activity is highly regulated by calcium. Structural studies with PAD2 revealed that calcium-binding occurs in a stepwise fashion and induces a series of dramatic conformational changes to form a catalytically competent active site. These studies also identified the presence of a calcium-switch that controls the overall calcium-dependence and a gatekeeper residue that shields the active site in the absence of calcium. Using biochemical and site-directed mutagenesis studies, we identified the key residues (two aspartates, a cysteine, and a histidine) responsible for catalysis and proposed a general mechanism of citrullination. Although all PADs follow this mechanism, substrate binding to the thiolate or thiol form of the enzyme varies for different isozymes. Substrate-specificity studies revealed that PADs 1-4 prefer peptidyl-arginine over free arginine and certain citrullination sites on a peptide substrate. Using high-throughput screening and activity-based protein profiling (ABPP), we identified several reversible (streptomycin, minocycline, and chlorotetracycline) and irreversible (streptonigrin, NSC 95397) PAD-inhibitors. Screening of a DNA-encoded library and lead-optimization led to the development of GSK199 and GSK484 as highly potent PAD4-selective inhibitors. Furthermore, use of an electrophilic, cysteine-targeted haloacetamidine warhead to mimic the guanidinium group in arginine afforded several mechanism-based pan-PAD-inhibitors including Cl-amidine and BB-Cl-amidine. These compounds are highly efficacious in various animal models, including those mimicking RA, UC, and lupus. Structure-activity relationships identified numerous covalent PAD-inhibitors with different bioavailability, in vivo stability, and isozyme-selectivity (PAD1-selective: D-Cl-amidine; PAD2-selective: compounds 16-20; PAD3-selective: Cl4-amidine; and PAD4-selective: TDFA). Finally, this Account describes the development of PAD-targeted and citrulline-specific chemical probes. While PAD-targeted probes were utilized for identifying off-targets and developing high-throughput inhibitor screening platforms, citrulline-specific probes enabled the proteomic identification of novel diagnostic biomarkers of hypercitrullination-related autoimmune diseases.
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Affiliation(s)
- Santanu Mondal
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
- Program in Chemical Biology, UMass Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
| | - Paul R. Thompson
- Department of Biochemistry and Molecular Pharmacology, UMass Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
- Program in Chemical Biology, UMass Medical School, 364 Plantation Street, Worcester, Massachusetts 01605, United States
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21
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Tilvawala R, Thompson PR. Peptidyl arginine deiminases: detection and functional analysis of protein citrullination. Curr Opin Struct Biol 2019; 59:205-215. [PMID: 30833201 DOI: 10.1016/j.sbi.2019.01.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 11/29/2022]
Abstract
Citrullination is a post-translational modification of arginine that is catalyzed by the protein arginine deiminases (PADs). Abnormal citrullination is observed in many autoimmune diseases and cancers. Anti-citrullinated protein antibodies (ACPA) are hallmarks of RA and used as diagnostic markers for disease diagnosis. Even though citrullination is associated with many different pathologies, its role remains unclear due to the challenges associated with the detection of citrullinated proteins since the mass change is only 0.984 Da. Moreover, the functional effects of protein citrullination remain mostly unknown. Herein, we discuss a brief overview of PAD structure and function, recent advances in the detection of citrullinated proteins in complex biological systems and the functional consequences of protein citrullination.
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Affiliation(s)
- Ronak Tilvawala
- Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Paul R Thompson
- Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States.
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22
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Guo Z, Shi L, Wang B, He G, Wang Y, Chen G. Synthesis of reversible PAD4 inhibitors via copper-catalyzed C−H arylation of benzimidazole. Sci China Chem 2019. [DOI: 10.1007/s11426-018-9409-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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23
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Nagar M, Tilvawala R, Thompson PR. Thioredoxin Modulates Protein Arginine Deiminase 4 (PAD4)-Catalyzed Citrullination. Front Immunol 2019; 10:244. [PMID: 30853960 PMCID: PMC6396667 DOI: 10.3389/fimmu.2019.00244] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 01/28/2019] [Indexed: 01/01/2023] Open
Abstract
Protein citrullination is a post-translational modification catalyzed by the protein arginine deiminases (PADs). This modification plays a crucial role in the pathophysiology of numerous autoimmune disorders including RA. Recently, there has been a growing interest in investigating physiological regulators of PAD activity to understand the primary cause of the associated disorders. Apart from calcium, it is well-documented that a reducing environment activates the PADs. Although the concentration of thioredoxin (hTRX), an oxidoreductase that maintains the cellular reducing environment, is elevated in RA patients, its contribution toward RA progression or PAD activity has not been explored. Herein, we demonstrate that hTRX activates PAD4. Kinetic characterization of PAD4 using hTRX as the reducing agent yielded parameters that are comparable to those obtained with a routinely used non-physiological reducing agent, e.g., DTT, suggesting the importance of hTRX in PAD regulation under physiological conditions. Furthermore, we show that various hTRX mutants, including redox inactive hTRX variants, are capable of activating PAD4. This indicates a mechanism that does not require oxidoreductase activity. Indeed, we observed non-covalent interactions between PAD4 and hTRX variants, and propose that these redox-independent interactions are sufficient for hTRX-mediated PAD4 activation.
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Affiliation(s)
- Mitesh Nagar
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, United States.,Program in Chemical Biology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Ronak Tilvawala
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, United States.,Program in Chemical Biology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Paul R Thompson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, United States.,Program in Chemical Biology, University of Massachusetts Medical School, Worcester, MA, United States
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24
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Ghalehshahi HG, Balalaie S, Sohbati HR, Azizian H, Alavijeh MS. Synthesis, CYP 450 evaluation, and docking simulation of novel 4-aminopyridine and coumarin derivatives. Arch Pharm (Weinheim) 2019; 352:e1800247. [DOI: 10.1002/ardp.201800247] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/01/2018] [Accepted: 12/05/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Hajar G. Ghalehshahi
- Peptide Chemistry Research Center; K. N. Toosi University of Technology; Tehran Iran
| | - Saeed Balalaie
- Peptide Chemistry Research Center; K. N. Toosi University of Technology; Tehran Iran
- Medical Biology Research Center; Kermanshah University of Medical Sciences; Kermanshah Iran
| | - Hamid R. Sohbati
- Faculty of Pharmacy, Department of Medicinal Chemistry; Tehran University of Medical Science; Tehran Iran
| | - Homa Azizian
- Department of Medicinal Chemistry, School of Pharmacy international Campus; Iran University of Medical Sciences; Tehran Iran
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25
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Ying TC, Ibrahim Z, Rahman MBA, Tejo BA. Structure-Based Design of Peptide Inhibitors for Protein Arginine Deiminase Type IV (PAD4). ENCYCLOPEDIA OF BIOINFORMATICS AND COMPUTATIONAL BIOLOGY 2019:729-740. [DOI: 10.1016/b978-0-12-809633-8.20156-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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26
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Khan MA, Philip LM, Cheung G, Vadakepeedika S, Grasemann H, Sweezey N, Palaniyar N. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis. Front Med (Lausanne) 2018; 5:19. [PMID: 29487850 PMCID: PMC5816902 DOI: 10.3389/fmed.2018.00019] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 01/19/2018] [Indexed: 01/24/2023] Open
Abstract
Neutrophils migrating from the blood (pH 7.35-7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10-20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3- ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar bicarbonate solution. For that reason, regulating NETosis by pH with specific buffers such as THAM could be more effective than bicarbonate in managing NET-related diseases.
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Affiliation(s)
- Meraj A Khan
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Lijy M Philip
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada
| | - Guillaume Cheung
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada
| | - Shawn Vadakepeedika
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada
| | - Hartmut Grasemann
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Neil Sweezey
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nades Palaniyar
- Program in Translational Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Massachusetts General Hospital, Shriners Hospitals for Children in Boston, Harvard Medical School, Boston, MA, United States
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Zhou Y, Mittereder N, Sims GP. Perspective on Protein Arginine Deiminase Activity-Bicarbonate Is a pH-Independent Regulator of Citrullination. Front Immunol 2018; 9:34. [PMID: 29403504 PMCID: PMC5778117 DOI: 10.3389/fimmu.2018.00034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/04/2018] [Indexed: 01/14/2023] Open
Abstract
Protein citrullination catalyzed by peptidyl arginine deiminase (PADs) is involved in autoimmune disease pathogenesis, especially in rheumatoid arthritis. Calcium is a key regulator of PAD activity, but under normal physiological conditions it remains uncertain how intracellular calcium levels can be raised to sufficiently high levels to activate these enzymes. In pursuit of trying to identify other factors that influence PAD activity, we identified bicarbonate as a potential regulator of PAD activity. We demonstrate that physiological levels of bicarbonate upregulate citrullination by recombinant PAD2/4 and endogenous PADs in neutrophils. The impact of bicarbonate is independent of calcium and pH. Adding bicarbonate to commercial PAD activity kits could increase assay performance and biological relevance. These results suggest that citrullination activity is regulated by multiple factors including calcium and bicarbonate. We also provide commentary on the current understanding of PAD regulation and future perspective of research in this area.
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Affiliation(s)
- Yebin Zhou
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Nanette Mittereder
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
| | - Gary P Sims
- Department of Respiratory, Inflammation, and Autoimmunity, MedImmune LLC, Gaithersburg, MD, United States
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Development of Activity-Based Proteomic Probes for Protein Citrullination. Curr Top Microbiol Immunol 2018; 420:233-251. [PMID: 30203394 DOI: 10.1007/82_2018_132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein arginine deiminases (PADs) catalyze the post-translational deimination of peptidyl arginine to form peptidyl citrulline. This modification is increased in multiple inflammatory diseases and in certain cancers. PADs regulate a variety of signaling pathways including apoptosis, terminal differentiation, and transcriptional regulation. Activity-based protein profiling (ABPP) probes have been developed to understand the role of the PADs in vivo and to investigate the effect of protein citrullination in various pathological conditions. Furthermore, these ABPPs have been utilized as a platform for high-throughput inhibitor discovery. This review will showcase the development of ABPPs targeting the PADs. In addition, it provides a brief overview of PAD structure and function along with recent advances in PAD inhibitor development.
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Frankel EA, Bevilacqua PC. Complexity in pH-Dependent Ribozyme Kinetics: Dark pK a Shifts and Wavy Rate-pH Profiles. Biochemistry 2017; 57:483-488. [PMID: 29271644 DOI: 10.1021/acs.biochem.7b00784] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Charged bases occur in RNA enzymes, or ribozymes, where they play key roles in catalysis. Cationic bases donate protons and perform electrostatic catalysis, while anionic bases accept protons. We previously published simulations of rate-pH profiles for ribozymes in terms of species plots for the general acid and general base that have been useful for understanding how ribozymes respond to pH. In that study, we did not consider interaction between the general acid and general base or interaction with other species on the RNA. Since that report, diverse small ribozyme classes have been discovered, many of which have charged nucleobases or metal ions in the active site that can either directly interact and participate in catalysis or indirectly interact as "influencers". Herein, we simulate experimental rate-pH profiles in terms of species plots in which reverse protonated charged nucleobases interact. These analyses uncover two surprising features of pH-dependent enzyme kinetics. (1) Cooperativity between the general acid and general base enhances population of the functional forms of a ribozyme and manifests itself as hidden or "dark" pKa shifts, real pKa shifts that accelerate the reaction but are not readily observed by standard experimental approaches, and (2) influencers favorably shift the pKas of proton-transferring nucleobases and manifest themselves as "wavy" rate-pH profiles. We identify parallels with the protein enzyme literature, including reverse protonation and wavelike behavior, while pointing out that RNA is more prone to reverse protonation. The complexities uncovered, which arise from simple pairwise interactions, should aid deconvolution of complex rate-pH profiles for RNA and protein enzymes and suggest veiled catalytic devices for promoting catalysis that can be tested by experiment and calculation.
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Affiliation(s)
- Erica A Frankel
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Center for RNA Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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Aratani S, Fujita H, Yagishita N, Yamano Y, Okubo Y, Nishioka K, Nakajima T. Inhibitory effects of ubiquitination of synoviolin by PADI4. Mol Med Rep 2017; 16:9203-9209. [DOI: 10.3892/mmr.2017.7764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 02/09/2017] [Indexed: 11/06/2022] Open
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Zhai Q, Wang L, Zhao P, Li T. Role of citrullination modification catalyzed by peptidylarginine deiminase 4 in gene transcriptional regulation. Acta Biochim Biophys Sin (Shanghai) 2017; 49:567-572. [PMID: 28472221 DOI: 10.1093/abbs/gmx042] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/06/2017] [Indexed: 12/20/2022] Open
Abstract
Peptidylarginine deiminase 4 (PADI4), a new histone modification enzyme, which converts both arginine and monomethyl-arginine to citrulline, has gained massive attention in recent years as a potential regulator of gene transcription. Recent studies have shown that arginine residues R2, R8, R17, and R26 in the H3 tail and R3 in the H4 tail can be deiminated by PADI4. This kind of histone post-translational modification has the potential to antagonize histone methylation and coordinate with histone deacetylation to regulate gene transcription. PADI4 also deiminates non-histone proteins, such as p300, NPM1, ING4, RPS2, and DNMT3A. PADI4 has been shown to involve in cell apoptosis and differentiation. Moreover, PADI4 can interact with tumor suppressor p53 and regulate the transcriptional activity of p53. Dysregulation of PADI4 is implicated in a variety of diseases, including rheumatoid arthritis, tumor development, and multiple sclerosis. A wide variety of PADI4 inhibitors have been identified. Further understanding of PADI4 functions may lead to novel diagnostic and therapeutic approaches in these diseases. This review summarizes the recent progress in the study of the regulation mechanism of PADI4 on gene transcription and the major physiological functions of PADI4 in human diseases.
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Affiliation(s)
- Qiaoli Zhai
- Center of Translational Medicine, Central Hospital of Zibo, Shandong University, Zibo 255036, China
| | - Lianqing Wang
- Center of Translational Medicine, Central Hospital of Zibo, Shandong University, Zibo 255036, China
| | - Peiqing Zhao
- Center of Translational Medicine, Central Hospital of Zibo, Shandong University, Zibo 255036, China
| | - Tao Li
- Center of Translational Medicine, Central Hospital of Zibo, Shandong University, Zibo 255036, China
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Probing the Roles of Calcium-Binding Sites during the Folding of Human Peptidylarginine Deiminase 4. Sci Rep 2017; 7:2429. [PMID: 28546558 PMCID: PMC5445078 DOI: 10.1038/s41598-017-02677-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 04/18/2017] [Indexed: 11/24/2022] Open
Abstract
Our recent studies of peptidylarginine deiminase 4 (PAD4) demonstrate that its non-catalytic Ca2+-binding sites play a crucial role in the assembly of the correct geometry of the enzyme. Here, we examined the folding mechanism of PAD4 and the role of Ca2+ ions in the folding pathway. Multiple mutations were introduced into the calcium-binding sites, and these mutants were termed the Ca1_site, Ca2_site, Ca3_site, Ca4_site and Ca5_site mutants. Our data indicate that during the unfolding process, the PAD4 dimer first dissociates into monomers, and the monomers then undergo a three-state denaturation process via an intermediate state formation. In addition, Ca2+ ions assist in stabilizing the folding intermediate, particularly through binding to the Ca3_site and Ca4_site to ensure the correct and active conformation of PAD4. The binding of calcium ions to the Ca1_site and Ca2_site is directly involved in the catalytic action of the enzyme. Finally, this study proposes a model for the folding of PAD4. The nascent polypeptide chains of PAD4 are first folded into monomeric intermediate states, then continue to fold into monomers, and ultimately assemble into a functional and dimeric PAD4 enzyme, and cellular Ca2+ ions may be the critical factor governing the interchange.
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Koushik S, Joshi N, Nagaraju S, Mahmood S, Mudeenahally K, Padmavathy R, Jegatheesan SK, Mullangi R, Rajagopal S. PAD4: pathophysiology, current therapeutics and future perspective in rheumatoid arthritis. Expert Opin Ther Targets 2017; 21:433-447. [PMID: 28281906 DOI: 10.1080/14728222.2017.1294160] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Peptidyl arginine deiminase 4 (PAD4) is an enzyme that plays an important role in gene expression, turning out genetic code into functional products in the body. It is involved in a key post translational modification, which involves the conversion of arginine to citrulline. It regulates various processes such as apoptosis, innate immunity and pluripotency, while its dysregulation has a great impact on the genesis of various diseases. Over the last few years PAD4 has emerged as a potential therapeutic target for the treatment of rheumatoid arthritis (RA). Areas covered: In this review, we discuss the basic structure and function of PAD4, along with the role of altered PAD4 activity in the onset of RA and other maladies. We also elucidate the role of PAD4 variants in etiology of RA among several ethnic groups and the current pre-clinical inhibitors to regulate PAD4. Expert opinion: Citrullination has a crucial role in RA and several other disorders. Since PAD4 is an initiator of the citrullination, it is an important therapeutic target for inflammatory diseases. Therefore, an in depth knowledge of the roles and activity of PAD4 is required to explore more effective ways to conquer PAD4 related ailments, especially RA.
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Affiliation(s)
- Sindhu Koushik
- a Bioinformatics , Jubilant Biosys Ltd ., Bangalore , India
| | - Nivedita Joshi
- a Bioinformatics , Jubilant Biosys Ltd ., Bangalore , India
| | | | - Sameer Mahmood
- a Bioinformatics , Jubilant Biosys Ltd ., Bangalore , India
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Amin B, Voelter W. Human Deiminases: Isoforms, Substrate Specificities, Kinetics, and Detection. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2017; 106:203-240. [PMID: 28762090 DOI: 10.1007/978-3-319-59542-9_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Peptidylarginine deiminase (PAD) enzymes are of enormous interest in biomedicine. They catalyze the conversion of a positively-charged guanidinium at an arginine side chain into a neutral ureido group. As a result of this conversion, proteins acquire the non-ribosomally encoded amino acid "citrulline". This imposes critical influences on the structure and function of the target molecules. In multiple sclerosis, myelin hyper-citrullination promotes demyelination by reducing its compaction and triggers auto-antibody production. Immune responses to citrulline-containing proteins play a central role in the pathogenesis of autoimmune diseases. Moreover, auto-antibodies, specific to citrullinated proteins, such as collagen type I and II and filaggrin, are early detectable in rheumatoid arthritis, serving as diagnostic markers of the disease. Despite their significance, little is understood about the role in demyelinating disorders, diversified cancers, and auto-immune diseases. To impart their biological and pathological effects, it is crucial to better understand the reaction mechanism, kinetic properties, substrate selection, and specificities of peptidylarginine deiminase isoforms.Many aspects of PAD biochemistry and physiology have been ignored in past, but, herein is presented a comprehensive survey to improve our current understandings of the underlying mechanism and regulation of PAD enzymes.
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Affiliation(s)
- Bushra Amin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, 15260, PA, USA.
| | - Wolfgang Voelter
- Interfacultary Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076, Tübingen, BW, Germany
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Mechanistic studies of the agmatine deiminase from Listeria monocytogenes. Biochem J 2016; 473:1553-61. [PMID: 27034081 PMCID: PMC4888459 DOI: 10.1042/bcj20160221] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/30/2016] [Indexed: 11/17/2022]
Abstract
Listeria monocytogenes is a Gram-positive food-borne pathogen that is capable of living within extreme environments (i.e. low temperatures and pH). This ability to survive in such conditions may arise, at least in part, from agmatine catabolism via the agmatine deiminase system (AgDS). This catabolic pathway utilizes an agmatine deiminase (AgD) to hydrolyse agmatine into N-carbamoylputrescine (NCP), with concomitant release of ammonia, which increases the pH, thus mitigating the ill effects of the acidic environment. Given the potential significance of this pathway for cell survival, we set out to study the catalytic mechanism of the AgD encoded by L. monocytogenes In the present paper, we describe the catalytic mechanism employed by this enzyme based on pH profiles, pKa measurements of the active site cysteine and solvent isotope effects (SIE). In addition, we report inhibition of this enzyme by two novel AgD inhibitors, i.e. N-(4-aminobutyl)-2-fluoro-ethanimidamide (ABFA) and N-(4-aminobutyl)-2-chloro-ethanimidamide (ABCA). In contrast with other orthologues, L. monocytogenes AgD does not use the reverse protonation or substrate-assisted mechanism, which requires an active site cysteine with a high pKa and has been commonly seen in other members of the guanidinium-modifying enzyme (GME) superfamily. Instead, the L. monocytogenes AgD has a low pKa cysteine in the active site leading to an alternative mechanism of catalysis. This is the first time that this mechanism has been observed in the GME superfamily and is significant because it explains why previously developed mechanism-based inactivators of AgDs are ineffective against this orthologue.
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36
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Bicker KL, Thompson PR. The protein arginine deiminases: Structure, function, inhibition, and disease. Biopolymers 2016; 99:155-63. [PMID: 23175390 DOI: 10.1002/bip.22127] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/24/2012] [Accepted: 07/06/2012] [Indexed: 12/11/2022]
Abstract
The post-translational modification of histones has significant effects on overall chromatin function. One such modification is citrullination, which is catalyzed by the protein arginine deiminases (PADs), a unique family of enzymes that catalyzes the hydrolysis of peptidyl-arginine to form peptidyl-citrulline on histones, fibrinogen, and other biologically relevant proteins. Overexpression and/or increased PAD activity is observed in several diseases, including rheumatoid arthritis, Alzheimer's disease, multiple sclerosis, lupus, Parkinson's disease, and cancer. This review discusses the important structural and mechanistic characteristics of the PADs, as well as recent investigations into the role of the PADs in increasing disease severity in RA and colitis and the importance of PAD activity in mediating neutrophil extracellular trap formation through chromatin decondensation. Lastly, efforts to develop PAD inhibitors with excellent potency, selectivity and in vivo efficacy are discussed, highlighting the most promising inhibitors.
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Affiliation(s)
- Kevin L Bicker
- Department of Chemistry, The Scripps Research Institute, Scripps Florida, 120 Scripps Way, Jupiter, FL 33458
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Externalized decondensed neutrophil chromatin occludes pancreatic ducts and drives pancreatitis. Nat Commun 2016; 7:10973. [PMID: 26964500 PMCID: PMC4793047 DOI: 10.1038/ncomms10973] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 02/08/2016] [Indexed: 02/07/2023] Open
Abstract
Ductal occlusion has been postulated to precipitate focal pancreatic inflammation,
while the nature of the primary occluding agents has remained elusive. Neutrophils
make use of histone citrullination by peptidyl arginine deiminase-4 (PADI4) in
contact to particulate agents to extrude decondensed chromatin as neutrophil
extracellular traps (NETs). In high cellular density, NETs form macroscopically
visible aggregates. Here we show that such aggregates form inside pancreatic ducts
in humans and mice occluding pancreatic ducts and thereby driving pancreatic
inflammation. Experimental models indicate that PADI4 is critical for intraductal
aggregate formation and that PADI4-deficiency abrogates disease progression.
Mechanistically, we identify the pancreatic juice as a strong instigator of
neutrophil chromatin extrusion. Characteristic single components of pancreatic
juice, such as bicarbonate ions and calcium carbonate crystals, induce aggregated
NET formation. Ductal occlusion by aggregated NETs emerges as a pathomechanism with
relevance in a plethora of inflammatory conditions involving secretory ducts. Pancreatitis often develops as a consequence of ductal obstruction.
Here, the authors show that bicarbonate ions initiate the release of neutrophil
extracellular traps (NETs) that form pancreatic ductal aggregates and occlude the ducts,
thereby driving pancreatitis in mice and humans.
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Fuhrmann J, Clancy K, Thompson PR. Chemical biology of protein arginine modifications in epigenetic regulation. Chem Rev 2015; 115:5413-61. [PMID: 25970731 PMCID: PMC4463550 DOI: 10.1021/acs.chemrev.5b00003] [Citation(s) in RCA: 206] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Indexed: 01/10/2023]
Affiliation(s)
- Jakob Fuhrmann
- Department
of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Kathleen
W. Clancy
- Department of Biochemistry and Molecular Pharmacology and Program in Chemical
Biology, University of Massachusetts Medical
School, 364 Plantation
Street, Worcester, Massachusetts 01605, United States
| | - Paul R. Thompson
- Department of Biochemistry and Molecular Pharmacology and Program in Chemical
Biology, University of Massachusetts Medical
School, 364 Plantation
Street, Worcester, Massachusetts 01605, United States
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Jamali H, Khan HA, Stringer JR, Chowdhury S, Ellman JA. Identification of multiple structurally distinct, nonpeptidic small molecule inhibitors of protein arginine deiminase 3 using a substrate-based fragment method. J Am Chem Soc 2015; 137:3616-21. [PMID: 25742366 PMCID: PMC4447334 DOI: 10.1021/jacs.5b00095] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The protein arginine deiminases (PADs) are a family of enzymes that catalyze the post-translational hydrolytic deimination of arginine residues. Four different enzymologically active PAD subtypes have been characterized and exhibit tissue-specific expression and association with a number of different diseases. In this Article we describe the development of an approach for the reliable discovery of low molecular weight, nonpeptidic fragment substrates of the PADs that then can be optimized and converted to mechanism-based irreversible PAD inhibitors. The approach is demonstrated by the development of potent and selective inhibitors of PAD3, a PAD subtype implicated in the neurodegenerative response to spinal cord injury. Multiple structurally distinct inhibitors were identified with the most potent inhibitors having >10,000 min(-1) M(-1) k(inact)/K(I) values and ≥10-fold selectivity for PAD3 over PADs 1, 2, and 4.
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Affiliation(s)
- Haya Jamali
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Hasan A. Khan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | | | | | - Jonathan A. Ellman
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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Witalison EE, Cui X, Hofseth AB, Subramanian V, Causey CP, Thompson PR, Hofseth LJ. Inhibiting protein arginine deiminases has antioxidant consequences. J Pharmacol Exp Ther 2015; 353:64-70. [PMID: 25635139 DOI: 10.1124/jpet.115.222745] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Ulcerative colitis is a dynamic, idiopathic, chronic inflammatory condition that carries a high colon cancer risk. We previously showed that Cl-amidine, a small-molecule inhibitor of the protein arginine deiminases, suppresses colitis in mice. Because colitis is defined as inflammation of the colon associated with infiltration of white blood cells that release free radicals and citrullination is an inflammation-dependent process, we asked whether Cl-amidine has antioxidant properties. Here we show that colitis induced with azoxymethane via intraperitoneal injection + 2% dextran sulfate sodium in the drinking water is suppressed by Cl-amidine (also given in the drinking water). Inducible nitric oxide synthase, an inflammatory marker, was also downregulated in macrophages by Cl-amidine. Because epithelial cell DNA damage associated with colitis is at least in part a result of an oxidative burst from overactive leukocytes, we tested the hypothesis that Cl-amidine can inhibit leukocyte activation, as well as subsequent target epithelial cell DNA damage in vitro and in vivo. Results are consistent with this hypothesis, and because DNA damage is a procancerous mechanism, our data predict that Cl-amidine will not only suppress colitis, but we hypothesize that it may prevent colon cancer associated with colitis.
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Affiliation(s)
- Erin E Witalison
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Xiangli Cui
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Anne B Hofseth
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Venkataraman Subramanian
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Corey P Causey
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Paul R Thompson
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
| | - Lorne J Hofseth
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina (E.E.W., X.C., A.B.H., L.J.H.); Shanxi Medical University, Taiyuan, Shanxi, China (X.C.); Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter, Florida (V.S.); Department of Chemistry, University of North Florida, Jacksonville, Florida (C.P.C.); and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts (P.R.T.)
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Theoretical study of the mechanism of protein arginine deiminase 4 (PAD4) inhibition by F-amidine. J Mol Graph Model 2014; 55:25-32. [PMID: 25424656 DOI: 10.1016/j.jmgm.2014.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/11/2014] [Accepted: 10/27/2014] [Indexed: 11/23/2022]
Abstract
Protein arginine deiminase 4 (PAD4) catalyzes the hydrolysis of a peptidylarginine residue to form a citrulline residue and ammonia during posttranslational modification. This process plays a pivotal role in rheumatoid arthritis (RA) and gene regulation. F-amidine belongs to a series of haloacetamidine compounds that are the most potent PAD4 inhibitors described to date. F-amidine acts as a mechanism-based inhibitor of PAD4, inactivating PAD4 by the covalent modification of the active site Cys645. In this manuscript, the fundamental mechanism of PAD4 inhibition by F-amidine is investigated using a QM/MM approach. Our simulations show that in the PAD4-F-amidine reactant complex, the active site Cys645 exists as a thiolate and His471 is protonated. This is consistent with the reverse protonation mechanism wherein the active site nucleophile, Cys645, in PAD4 exists as a thiolate in the active form of the enzyme. Inhibition of PAD4 by F-amidine is initiated by the nucleophilic addition of Sγ to the Cζ of F-amidine, leading to the formation of a tetrahedral intermediate. His471 serves as a proton donor, helping F to leave the fluoroacetamidine moiety of F-amidine; meanwhile, Sγ forms a three-membered ring with Cζ and Cη of F-amidine. Subsequently, the three-membered sulfonium ring collapses and rearranges to the final thioether product. His471 acts as a proton donor in the transition state and facilitates the inhibition reaction of PAD4.
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Dreyton CJ, Knuckley B, Jones JE, Lewallen DM, Thompson PR. Mechanistic studies of protein arginine deiminase 2: evidence for a substrate-assisted mechanism. Biochemistry 2014; 53:4426-33. [PMID: 24989433 PMCID: PMC4100781 DOI: 10.1021/bi500554b] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
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Citrullination, which is catalyzed
by protein arginine deiminases
(PADs 1–4 and 6), is a post-translational modification (PTM)
that effectively neutralizes the positive charge of a guanidinium
group by its replacement with a neutral urea. Given the sequence similarity
of PAD2 across mammalian species and the genomic organization of the
PAD2 gene, PAD2 is predicted to be the ancestral homologue of the
PADs. Although PAD2 has long been known to play a role in myelination,
it has only recently been linked to other cellular processes, including
gene transcription and macrophage extracellular trap formation. For
example, PAD2 deiminates histone H3 at R26, and this PTM leads to
the increased transcription of more than 200 genes under the control
of the estrogen receptor. Given that our understanding of PAD2 biology
remains incomplete, we initiated mechanistic studies on this enzyme
to aid the development of PAD2-specific inhibitors. Herein, we report
that the substrate specificity and calcium dependence of PAD2 are
similar to those of PADs 1, 3, and 4. However, unlike those isozymes,
PAD2 appears to use a substrate-assisted mechanism of catalysis in
which the positively charged substrate guanidinium depresses the pKa of the nucleophilic cysteine. By contrast,
PADs 1, 3, and 4 use a reverse-protonation mechanism. These mechanistic
differences will aid the development of isozyme-specific inhibitors.
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Affiliation(s)
- Christina J Dreyton
- Department of Chemistry and The Kellogg School of Graduate Studies, The Scripps Research Institute-Florida , 130 Scripps Way, Jupiter, Florida 33458, United States
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Dreyton CJ, Anderson ED, Subramanian V, Boger DL, Thompson PR. Insights into the mechanism of streptonigrin-induced protein arginine deiminase inactivation. Bioorg Med Chem 2014; 22:1362-9. [PMID: 24440480 DOI: 10.1016/j.bmc.2013.12.064] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/18/2013] [Accepted: 12/29/2013] [Indexed: 10/25/2022]
Abstract
Protein citrullination is just one of more than 200 known PTMs. This modification, catalyzed by the protein arginine deiminases (PADs 1-4 and PAD6 in humans), converts the positively charged guanidinium group of an arginine residue into a neutral ureido-group. Given the strong links between dysregulated PAD activity and human disease, we initiated a program to develop PAD inhibitors as potential therapeutics for these and other diseases in which the PADs are thought to play a role. Streptonigrin which possesses both anti-tumor and anti-bacterial activity was later identified as a highly potent PAD4 inhibitor. In an effort to understand why streptonigrin is such a potent and selective PAD4 inhibitor, we explored its structure-activity relationships by examining the inhibitory effects of several analogues that mimic the A, B, C, and/or D rings of streptonigrin. We report the identification of the 7-amino-quinoline-5,8-dione core of streptonigrin as a highly potent pharmacophore that acts as a pan-PAD inhibitor.
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Affiliation(s)
- Christina J Dreyton
- Department of Chemistry and The Kellogg School of Graduate Studies, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Erin D Anderson
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Venkataraman Subramanian
- Department of Chemistry and The Kellogg School of Graduate Studies, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Dale L Boger
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Paul R Thompson
- Department of Chemistry and The Kellogg School of Graduate Studies, The Scripps Research Institute-Florida, 130 Scripps Way, Jupiter, FL 33458, United States.
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Robbins JM, Ellis HR. Steady-state kinetic isotope effects support a complex role of Arg226 in the proposed desulfonation mechanism of alkanesulfonate monooxygenase. Biochemistry 2013; 53:161-8. [PMID: 24321058 DOI: 10.1021/bi401234e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The alkanesulfonate monooxygenase system catalyzes the desulfonation of alkanesulfonates through proposed acid-base mechanistic steps that involves the abstraction of a proton from the alkane peroxyflavin intermediate and protonation of the FMN-O(-) intermediate. Both solvent and kinetic isotope studies were performed to define the proton transfer steps involved in the SsuD reaction. Substitution of the protium at the C1 position of octanesulfonate with deuterium resulted in an observed primary isotope effect of 3.0 ± 0.2 on the kcat parameter, supporting abstraction of the α-proton from the alkane peroxyflavin as the rate-limiting step in catalysis. Previous studies implicated Arg226 as the acid involved in the reprotonation of the hydroxyflavin intermediate. Solvent isotope kinetic studies gave an inverse isotope effect on (D2O)kcat of 0.75 ± 0.04 with no observable effect on (D2O)kcat/Km. This resulted in equivalent solvent isotope effects on (D2O)kcat and (D2O)(kcat)D, suggesting a solvent equilibrium isotope effect on a step occurring after the first irreversible step through product release. Data from proton inventory studies on kcat were best fit to a dome-shaped curve consistent with a conformational change to an open conformation during product release. The solvent isotope effect data coupled with the corresponding proton inventory results support and extend our previous observations that Arg226 donates a proton to the FMN-O(-) intermediate, triggering a conformational change that opens the enzyme to solvation and promotes product release.
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Affiliation(s)
- John M Robbins
- Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States
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Dwivedi N, Radic M. Citrullination of autoantigens implicates NETosis in the induction of autoimmunity. Ann Rheum Dis 2013; 73:483-91. [PMID: 24291655 DOI: 10.1136/annrheumdis-2013-203844] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tolerance blocks the expression of autoantibodies, whereas autoimmunity promotes it. How tolerance breaks and autoantibody production begins thus are crucial questions for understanding and treatment of autoimmune diseases. Evidence implicates cell death and autoantigen modifications in the initiation of autoimmune reactions. One form of neutrophil cell death called NETosis deserves attention because it requires the post-translational modification of histones and results in the extracellular release of chromatin. NETosis received its name from NET, the acronym given to Neutrophil Extracellular Trap. The extracellular chromatin incorporates histones in which arginines have been converted to citrullines by peptidylarginine deiminase IV (PAD4). The deiminated chromatin may function to capture or 'trap' bacterial pathogens, thus generating an extracellular complex of deiminated histones and bacterial cell adjuvants. The complex of bacterial antigens and deiminated chromatin may be internalised by host phagocytes during acute inflammatory conditions, as arise during bacterial infections or chronic autoinflammatory disorders. The uptake and processing of deiminated chromatin together with bacterial adjuvants by phagocytes may induce the presentation of modified histone epitopes and co-stimulation, thus yielding a powerful stimulus to break tolerance. Autoantibodies to deiminated histones are prevalent in Felty's syndrome patients and are present in systemic lupus erythematosus (SLE) and patients with rheumatoid arthritis (RA). These observations clearly implicate histone deimination as an epigenetic mark that can act as an autoantibody stimulant.
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Affiliation(s)
- Nishant Dwivedi
- Program in Cellular and Molecular Medicine, Boston Children's Hospital and Harvard Medical School, , Boston, Massachusetts, USA
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Bello AM, Wasilewski E, Wei L, Moscarello MA, Kotra LP. Interrogation of the Active Sites of Protein Arginine Deiminases (PAD1, -2, and -4) Using Designer Probes. ACS Med Chem Lett 2013; 4:249-53. [PMID: 24900657 DOI: 10.1021/ml300377d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 01/15/2013] [Indexed: 11/29/2022] Open
Abstract
Protein arginine deiminases (PADs) are involved in a number of cellular pathways, and they catalyze the transformation of peptidyl arginine residue into a citrulline as part of post-translational modifications. To understand ligand preferences, a group of probe molecules were investigated against PAD1, PAD2, and PAD4. These probe molecules carried a well-known covalent modifier of the catalytic cysteine residue, 2-chloroacetamidine moiety, which was tethered to an α-amino acid via a carbon linker. The chain length for the linker varied from 0 to 4. Time-dependent assays indicated that 2-chloroacetamidine (2CA) with no linker inhibited all PAD enzymes with a similar trend in the second-order rate constants, although with poor affinity. Among the other three probe molecules, compound 3 with a three-carbon linker exhibited the best second-order rate constants for optimal ligand reactivity with the binding site. These analyses provide insights into the relative patterns of covalent inactivation of PAD isozymes and the design of novel inhibitors targeting PAD enzymes as potential therapeutic targets.
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Affiliation(s)
- Angelica M. Bello
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2, Canada
| | | | - Lianhu Wei
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2, Canada
| | - Mario A. Moscarello
- Department of Structural Biology and Biochemistry, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Lakshmi P. Kotra
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2, Canada
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Liu YL, Tsai IC, Chang CW, Liao YF, Liu GY, Hung HC. Functional roles of the non-catalytic calcium-binding sites in the N-terminal domain of human peptidylarginine deiminase 4. PLoS One 2013; 8:e51660. [PMID: 23382808 PMCID: PMC3559651 DOI: 10.1371/journal.pone.0051660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/06/2012] [Indexed: 11/19/2022] Open
Abstract
This study investigated the functional roles of the N-terminal Ca2+ ion-binding sites, in terms of enzyme catalysis and stability, of peptidylarginine deiminase 4 (PAD4). Amino acid residues located in the N-terminal Ca2+-binding site of PAD4 were mutated to disrupt the binding of Ca2+ ions. Kinetic data suggest that Asp155, Asp157 and Asp179, which directly coordinate Ca3 and Ca4, are essential for catalysis in PAD4. For D155A, D157A and D179A, the kcat/Km,BAEE values were 0.02, 0.63 and 0.01 s−1mM−1 (20.8 s−1mM−1 for WT), respectively. Asn153 and Asp176 are directly coordinated with Ca3 and indirectly coordinated with Ca5 via a water molecule. However, N153A displayed low enzymatic activity with a kcat value of 0.3 s−1 (13.3 s−1 for wild-type), whereas D176A retained some catalytic power with a kcat of 9.7 s−1. Asp168 is the direct ligand for Ca5, and Ca5 coordination by Glu252 is mediated by two water molecules. However, mutation of these two residues to Ala did not cause a reduction in the kcat/Km,BAEE values, which indicates that the binding of Ca5 may not be required for PAD4 enzymatic activity. The possible conformational changes of these PAD4 mutants were examined. Thermal stability analysis of the PAD4 mutants in the absence or presence of Ca2+ indicated that the conformational stability of the enzyme is highly dependent on Ca2+ ions. In addition, the results of urea-induced denaturation for the N153, D155, D157 and D179 series mutants further suggest that the binding of Ca2+ ions in the N-terminal Ca2+-binding site stabilizes the overall conformational stability of PAD4. Therefore, our data strongly suggest that the N-terminal Ca2+ ions play critical roles in the full activation of the PAD4 enzyme.
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Affiliation(s)
- Yi-Liang Liu
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- Institute of Microbiology & Immunology, Chung Shan Medical University, and Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - I-Chen Tsai
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Chia-Wei Chang
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
| | - Ya-Fan Liao
- Graduate Institute of Biochemical Sciences and Biotechnology, Chaoyang University of Technology Taichung, Taichung, Taiwan
| | - Guang-Yaw Liu
- Institute of Microbiology & Immunology, Chung Shan Medical University, and Division of Allergy, Immunology, and Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
| | - Hui-Chih Hung
- Department of Life Sciences and Institute of Genomics and Bioinformatics, National Chung-Hsing University, Taichung, Taiwan
- Agricultural Biotechnology Center (ABC), National Chung Hsing University, Taichung, Taiwan
- * E-mail: (HCH); (GYL)
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Teo CY, Shave S, Chor ALT, Salleh AB, Rahman MBBA, Walkinshaw MD, Tejo BA. Discovery of a new class of inhibitors for the protein arginine deiminase type 4 (PAD4) by structure-based virtual screening. BMC Bioinformatics 2012; 13 Suppl 17:S4. [PMID: 23282142 PMCID: PMC3521205 DOI: 10.1186/1471-2105-13-s17-s4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rheumatoid arthritis (RA) is an autoimmune disease with unknown etiology. Anticitrullinated protein autoantibody has been documented as a highly specific autoantibody associated with RA. Protein arginine deiminase type 4 (PAD4) is the enzyme responsible for catalyzing the conversion of peptidylarginine into peptidylcitrulline. PAD4 is a new therapeutic target for RA treatment. In order to search for inhibitors of PAD4, structure-based virtual screening was performed using LIDAEUS (Ligand discovery at Edinburgh university). Potential inhibitors were screened experimentally by inhibition assays. RESULTS Twenty two of the top-ranked water-soluble compounds were selected for inhibitory screening against PAD4. Three compounds showed significant inhibition of PAD4 and their IC50 values were investigated. The structures of the three compounds show no resemblance with previously discovered PAD4 inhibitors, nor with existing drugs for RA treatment. CONCLUSION Three compounds were discovered as potential inhibitors of PAD4 by virtual screening. The compounds are commercially available and can be used as scaffolds to design more potent inhibitors against PAD4.
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Affiliation(s)
- Chian Ying Teo
- Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Malaysia
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Abstract
Peptidylarginine deiminases, or PADs, convert arginine residues to the non-ribosomally encoded amino acid citrulline in a variety of protein substrates. PAD4 is expressed in granulocytes and is essential for the formation of neutrophil extracellular traps (NETs) via PAD4-mediated histone citrullination. Citrullination of histones is thought to promote NET formation by inducing chromatin decondensation and facilitating the expulsion of chromosomal DNA that is coated with antimicrobial molecules. Numerous stimuli have been reported to lead to PAD4 activation and NET formation. However, how this signaling process proceeds and how PAD4 becomes activated in cells is largely unknown. Herein, we describe the various stimuli and signaling pathways that have been implicated in PAD4 activation and NET formation, including the role of reactive oxygen species generation. To provide a foundation for the above discussion, we first describe PAD4 structure and function, and how these studies led to the development of PAD-specific inhibitors. A comprehensive survey of the receptors and signaling pathways that regulate PAD4 activation will be important for our understanding of innate immunity, and the identification of signaling intermediates in PAD4 activation may also lead to the generation of pharmaceuticals to target NET-related pathogenesis.
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Affiliation(s)
- Amanda S. Rohrbach
- Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
| | - Daniel J. Slade
- Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
| | - Paul R. Thompson
- Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
| | - Kerri A. Mowen
- Department of Chemical Physiology, The Scripps Research InstituteLa Jolla, CA, USA
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50
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Semimicroscopic investigation of active site pK a values in peptidylarginine deiminase 4. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1293-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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