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Quigley EB, DeVore SB, Khan SA, Geisterfer ZM, Rothfuss HM, Sequoia AO, Thompson PR, Gatlin JC, Cherrington BD, Navratil AM. GnRH Induces Citrullination of the Cytoskeleton in Murine Gonadotrope Cells. Int J Mol Sci 2024; 25:3181. [PMID: 38542155 PMCID: PMC10970285 DOI: 10.3390/ijms25063181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/06/2024] Open
Abstract
Peptidylarginine deiminases (PADs or PADIs) catalyze the conversion of positively charged arginine to neutral citrulline, which alters target protein structure and function. Our previous work established that gonadotropin-releasing hormone agonist (GnRHa) stimulates PAD2-catalyzed histone citrullination to epigenetically regulate gonadotropin gene expression in the gonadotrope-derived LβT2 cell line. However, PADs are also found in the cytoplasm. Given this, we used mass spectrometry (MS) to identify additional non-histone proteins that are citrullinated following GnRHa stimulation and characterized the temporal dynamics of this modification. Our results show that actin and tubulin are citrullinated, which led us to hypothesize that GnRHa might induce their citrullination to modulate cytoskeletal dynamics and architecture. The data show that 10 nM GnRHa induces the citrullination of β-actin, with elevated levels occurring at 10 min. The level of β-actin citrullination is reduced in the presence of the pan-PAD inhibitor biphenyl-benzimidazole-Cl-amidine (BB-ClA), which also prevents GnRHa-induced actin reorganization in dispersed murine gonadotrope cells. GnRHa induces the citrullination of β-tubulin, with elevated levels occurring at 30 min, and this response is attenuated in the presence of PAD inhibition. To examine the functional consequence of β-tubulin citrullination, we utilized fluorescently tagged end binding protein 1 (EB1-GFP) to track the growing plus end of microtubules (MT) in real time in transfected LβT2 cells. Time-lapse confocal microscopy of EB1-GFP reveals that the MT average lifetime increases following 30 min of GnRHa treatment, but this increase is attenuated by PAD inhibition. Taken together, our data suggest that GnRHa-induced citrullination alters actin reorganization and MT lifetime in gonadotrope cells.
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Affiliation(s)
- Elizabeth B. Quigley
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA; (E.B.Q.); (A.O.S.); (A.M.N.)
| | - Stanley B. DeVore
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Asthma Research, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
| | | | - Zachary M. Geisterfer
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA;
| | - Heather M. Rothfuss
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA; (E.B.Q.); (A.O.S.); (A.M.N.)
| | - Ari O. Sequoia
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA; (E.B.Q.); (A.O.S.); (A.M.N.)
| | - Paul R. Thompson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA;
| | - Jesse C. Gatlin
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA;
| | - Brian D. Cherrington
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA; (E.B.Q.); (A.O.S.); (A.M.N.)
| | - Amy M. Navratil
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA; (E.B.Q.); (A.O.S.); (A.M.N.)
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2
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Christophorou MA. The virtues and vices of protein citrullination. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220125. [PMID: 35706669 PMCID: PMC9174705 DOI: 10.1098/rsos.220125] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/16/2022] [Indexed: 05/03/2023]
Abstract
The post-translational modification of proteins expands the regulatory scope of the proteome far beyond what is achievable through genome regulation. The field of protein citrullination has seen significant progress in the last two decades. The small family of peptidylarginine deiminase (PADI or PAD) enzymes, which catalyse citrullination, have been implicated in virtually all facets of molecular and cell biology, from gene transcription and epigenetics to cell signalling and metabolism. We have learned about their association with a remarkable array of disease states and we are beginning to understand how they mediate normal physiological functions. However, while the biochemistry of PADI activation has been worked out in exquisite detail in vitro, we still lack a clear mechanistic understanding of the processes that regulate PADIs within cells, under physiological and pathophysiological conditions. This review summarizes and discusses the current knowledge, highlights some of the unanswered questions of immediate importance and gives a perspective on the outlook of the citrullination field.
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Abstract
As the main protein components of chromatin, histones play central roles in gene regulation as spools of winding DNA. Histones are subject to various modifications, including phosphorylation, acetylation, glycosylation, methylation, ubiquitination and citrullination, which affect gene transcription. Histone citrullination, a posttranscriptional modification catalyzed by peptidyl arginine deiminase (PAD) enzymes, is involved in human carcinogenesis. In this study, we highlighted the functions of histone citrullination in physiological regulation and tumors. Additionally, because histone citrullination involves forming neutrophil extracellular traps (NETs), the relationship between NETs and tumors was illustrated. Finally, the clinical application of histone citrullination and PAD inhibitors was discussed.
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Affiliation(s)
- Dongwei Zhu
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212013, China
- Department of Immunology, Jiangsu Key Laboratory of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yue Zhang
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212013, China.
| | - Shengjun Wang
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212013, China.
- Department of Immunology, Jiangsu Key Laboratory of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China.
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4
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Yang ML, Sodré FMC, Mamula MJ, Overbergh L. Citrullination and PAD Enzyme Biology in Type 1 Diabetes - Regulators of Inflammation, Autoimmunity, and Pathology. Front Immunol 2021; 12:678953. [PMID: 34140951 PMCID: PMC8204103 DOI: 10.3389/fimmu.2021.678953] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/11/2021] [Indexed: 02/06/2023] Open
Abstract
The generation of post-translational modifications (PTMs) in human proteins is a physiological process leading to structural and immunologic variety in proteins, with potentially altered biological functions. PTMs often arise through normal responses to cellular stress, including general oxidative changes in the tissue microenvironment and intracellular stress to the endoplasmic reticulum or immune-mediated inflammatory stresses. Many studies have now illustrated the presence of 'neoepitopes' consisting of PTM self-proteins that induce robust autoimmune responses. These pathways of inflammatory neoepitope generation are commonly observed in many autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and type 1 diabetes (T1D), among others. This review will focus on one specific PTM to self-proteins known as citrullination. Citrullination is mediated by calcium-dependent peptidylarginine deiminase (PAD) enzymes, which catalyze deimination, the conversion of arginine into the non-classical amino acid citrulline. PADs and citrullinated peptides have been associated with different autoimmune diseases, notably with a prominent role in the diagnosis and pathology of rheumatoid arthritis. More recently, an important role for PADs and citrullinated self-proteins has emerged in T1D. In this review we will provide a comprehensive overview on the pathogenic role for PADs and citrullination in inflammation and autoimmunity, with specific focus on evidence for their role in T1D. The general role of PADs in epigenetic and transcriptional processes, as well as their crucial role in histone citrullination, neutrophil biology and neutrophil extracellular trap (NET) formation will be discussed. The latter is important in view of increasing evidence for a role of neutrophils and NETosis in the pathogenesis of T1D. Further, we will discuss the underlying processes leading to citrullination, the genetic susceptibility factors for increased recognition of citrullinated epitopes by T1D HLA-susceptibility types and provide an overview of reported autoreactive responses against citrullinated epitopes, both of T cells and autoantibodies in T1D patients. Finally, we will discuss recent observations obtained in NOD mice, pointing to prevention of diabetes development through PAD inhibition, and the potential role of PAD inhibitors as novel therapeutic strategy in autoimmunity and in T1D in particular.
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Affiliation(s)
- Mei-Ling Yang
- Section of Rheumatology, Allergy and Clinical Immunology, Department of Internal Medicine, Yale University, New Haven, CT, United States
| | - Fernanda M C Sodré
- Department of Chronic Diseases, Metabolism and Ageing, Laboratory of Clinical and Experimental Endocrinology (CEE), KU Leuven, Leuven, Belgium
| | - Mark J Mamula
- Section of Rheumatology, Allergy and Clinical Immunology, Department of Internal Medicine, Yale University, New Haven, CT, United States
| | - Lut Overbergh
- Department of Chronic Diseases, Metabolism and Ageing, Laboratory of Clinical and Experimental Endocrinology (CEE), KU Leuven, Leuven, Belgium
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Peptidylarginine Deiminase Inhibitor Application, Using Cl-Amidine, PAD2, PAD3 and PAD4 Isozyme-Specific Inhibitors in Pancreatic Cancer Cells, Reveals Roles for PAD2 and PAD3 in Cancer Invasion and Modulation of Extracellular Vesicle Signatures. Int J Mol Sci 2021; 22:ijms22031396. [PMID: 33573274 PMCID: PMC7866560 DOI: 10.3390/ijms22031396] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies with limited survival rate. Roles for peptidylarginine deiminases (PADs) have been studied in relation to a range of cancers with roles in epigenetic regulation (including histone modification and microRNA regulation), cancer invasion, and extracellular vesicle (EV) release. Hitherto though, knowledge on PADs in PDAC is limited. In the current study, two PDAC cell lines (Panc-1 and MiaPaCa-2) were treated with pan-PAD inhibitor Cl-amidine as well as PAD2, PAD3, and PAD4 isozyme-specific inhibitors. Effects were assessed on changes in EV signatures, including EV microRNA cargo (miR-21, miR-126, and miR-221), on changes in cellular protein expression relevant for pancreatic cancer progression and invasion (moesin), for mitochondrial housekeeping (prohibitin, PHB), and gene regulation (deiminated histone H3, citH3). The two pancreatic cancer cell lines were found to predominantly express PAD2 and PAD3, which were furthermore expressed at higher levels in Panc-1, compared with MiaPaCa-2 cells. PAD2 isozyme-specific inhibitor had the strongest effects on reducing Panc-1 cell invasion capability, which was accompanied by an increase in moesin expression, which in pancreatic cancer is found to be reduced and associated with pancreatic cancer aggressiveness. Some reduction, but not significant, was also found on PHB levels while effects on histone H3 deimination were variable. EV signatures were modulated in response to PAD inhibitor treatment, with the strongest effects observed for PAD2 inhibitor, followed by PAD3 inhibitor, showing significant reduction in pro-oncogenic EV microRNA cargo (miR-21, miR-221) and increase in anti-oncogenic microRNA cargo (miR-126). While PAD2 inhibitor, followed by PAD3 inhibitor, had most effects on reducing cancer cell invasion, elevating moesin expression, and modulating EV signatures, PAD4 inhibitor had negligible effects and pan-PAD inhibitor Cl-amidine was also less effective. Compared with MiaPaCa-2 cells, stronger modulatory effects for the PAD inhibitors were observed in Panc-1 cells, which importantly also showed strong response to PAD3 inhibitor, correlating with previous observations that Panc-1 cells display neuronal/stem-like properties. Our findings report novel PAD isozyme regulatory roles in PDAC, highlighting roles for PAD isozyme-specific treatment, depending on cancer type and cancer subtypes, including in PDAC.
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6
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Zheng L, Nagar M, Maurais AJ, Slade DJ, Parelkar SS, Coonrod SA, Weerapana E, Thompson PR. Calcium Regulates the Nuclear Localization of Protein Arginine Deiminase 2. Biochemistry 2019; 58:3042-3056. [PMID: 31243954 DOI: 10.1021/acs.biochem.9b00225] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein arginine deiminases (PADs) are calcium-dependent enzymes that mediate the post-translational conversion of arginine into citrulline. Dysregulated PAD activity is associated with numerous autoimmune disorders and cancers. In breast cancer, PAD2 citrullinates histone H3R26 and activates the transcription of estrogen receptor target genes. However, PAD2 lacks a canonical nuclear localization sequence, and it is unclear how this enzyme is transported into the nucleus. Here, we show for the first time that PAD2 translocates into the nucleus in response to calcium signaling. Using BioID2, a proximity-dependent biotinylation method for identifying interacting proteins, we found that PAD2 preferentially associates with ANXA5 in the cytoplasm. Binding of calcium to PAD2 weakens this cytoplasmic interaction, which generates a pool of calcium-bound PAD2 that can interact with Ran. We hypothesize that this latter interaction promotes the translocation of PAD2 into the nucleus. These findings highlight a critical role for ANXA5 in regulating PAD2 and identify an unusual mechanism whereby proteins translocate between the cytosol and nucleus.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01605 , United States.,Program in Chemical Biology , University of Massachusetts Medical School , 364 Plantation Street , Worcester , Massachusetts 01605 , United States
| | - Mitesh Nagar
- Department of Biochemistry and Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01605 , United States.,Program in Chemical Biology , University of Massachusetts Medical School , 364 Plantation Street , Worcester , Massachusetts 01605 , United States
| | - Aaron J Maurais
- Department of Chemistry , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Daniel J Slade
- Department of Biochemistry , Virginia Polytechnic Institute and State University , Blacksburg , Virginia 24061 , United States
| | - Sangram S Parelkar
- Department of Biochemistry and Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01605 , United States
| | - Scott A Coonrod
- James A. Baker Institute for Animal Health, College of Veterinary Medicine , Cornell University , Ithaca , New York 14853 , United States
| | - Eranthie Weerapana
- Department of Chemistry , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Paul R Thompson
- Department of Biochemistry and Pharmacology , University of Massachusetts Medical School , Worcester , Massachusetts 01605 , United States.,Program in Chemical Biology , University of Massachusetts Medical School , 364 Plantation Street , Worcester , Massachusetts 01605 , United States
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7
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Kunieda K, Kawaguchi M, Ieda N, Nakagawa H. Development of a highly sensitive fluorescence probe for peptidyl arginine deiminase (PAD) activity. Bioorg Med Chem Lett 2019; 29:923-928. [PMID: 30773431 DOI: 10.1016/j.bmcl.2019.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022]
Abstract
Peptidyl arginine deiminases (PADs) catalyze the post-translational deimination of arginine residues to citrulline residues. Aberrant levels of PAD activity are associated with various diseases, such as rheumatoid arthritis, Alzheimer's disease, and multiple sclerosis, so there is a need for simple and convenient high-throughput screening systems to discover PAD inhibitors as candidate therapeutic agents. Here, we report a highly sensitive off/on-type fluorescence probe for PAD activity based on the donor-excited photoinduced electron transfer (d-PeT) mechanism, utilizing the specific cycloaddition reaction between the benzil group of the probe and the ureido group of the PAD product, citrulline, under acidic conditions. We synthesized and functionally evaluated a series of probes bearing substituents on the benzil phenyl group, and found that 4MEBz-FluME could successfully detect citrulline with higher sensitivity and broader dynamic range than our previously reported fluorescence probe, FGME. Moreover, we succeeded in establishing multiple assay systems for PAD subtypes activities, including PAD2 and PAD4, with 4MeBz-FluME thanks to its high sensitivity. We expect that our fluorescence probes will become a powerful tool for discovering PAD inhibitors of several subtypes. Thus, it should be suitable for high-throughput screening of chemical libraries for inhibitors of PADs.
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Affiliation(s)
- Kazuki Kunieda
- Graduate School of Pharmaceutical Science, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi, Japan
| | - Mitsuyasu Kawaguchi
- Graduate School of Pharmaceutical Science, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi, Japan
| | - Naoya Ieda
- Graduate School of Pharmaceutical Science, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi, Japan
| | - Hidehiko Nakagawa
- Graduate School of Pharmaceutical Science, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi, Japan.
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8
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Kim SE, Park JW, Kim MJ, Jang B, Jeon YC, Kim HJ, Ishigami A, Kim HS, Suk KT, Kim DJ, Park CK, Choi EK, Jang MK. Accumulation of citrullinated glial fibrillary acidic protein in a mouse model of bile duct ligation-induced hepatic fibrosis. PLoS One 2018; 13:e0201744. [PMID: 30071078 PMCID: PMC6072123 DOI: 10.1371/journal.pone.0201744] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 07/20/2018] [Indexed: 01/26/2023] Open
Abstract
Hepatic stellate cells (HSCs) play pivotal roles in hepatic fibrosis as they synthesize glial fibrillary acidic protein (GFAP), which is increased in activated HSCs. GFAP-expressing HSCs and myofibroblasts accumulate in and around hepatic fibrosis lesions. Peptidylarginine deiminase 2 (PAD2) is responsible for the citrullination of GFAP (cit-GFAP). However, the involvement of PAD2 and cit-GFAP in hepatic fibrosis remains unclear. To determine the expression of PAD2 and cit-GFAP in hepatic fibrosis, C57BL/6 mice underwent bile duct ligation (BDL) or a sham operation. In BDL livers, the expression of PAD2 and its enzyme activity were significantly increased compared with controls. In addition, PAD2-postitive cells were rarely observed in only the portal vein and the small bile duct in sham-operated livers, whereas an increased number of PAD2-positive cells were detected in the bile duct and Glisson’s sheath in BDL livers. Interestingly, PAD2 was colocalized with α-SMA-positive cells and CK19-positive cells in BDL livers, indicating upregulated PAD2 in activated HSCs and portal fibroblasts of the livers of BDL mice. We also found that citrullinated proteins were highly accumulated in the livers of BDL mice compared with controls. Moreover, the expression level of GFAP and the amount of cit-GFAP were higher in BDL livers than in control livers. In correlation with PAD2 localization, cit-GFAP was observed in α-SMA-positive and CK19-positive cells in the livers of BDL mice. These results suggest that the increased expression and activation of PAD2 along with increased citrullinated proteins, specifically cit-GFAP, may play important roles in the pathogenesis of hepatic fibrosis.
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Affiliation(s)
- Sung-Eun Kim
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, Republic of Korea
| | - Ji Won Park
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, Republic of Korea
| | - Mo-Jong Kim
- Department of Biomedical Gerontology, Graduate School of Hallym University, Anyang, Republic of Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
| | - Byungki Jang
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
| | - Yong-Chul Jeon
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
| | - Hee-Jun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
| | - Akihito Ishigami
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Hyoung Su Kim
- Department of Internal Medicine, Kangdong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Republic of Korea
| | - Ki Tae Suk
- Department of Internal Medicine, Chuncheon Sacred Heart Hospital, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Dong Joon Kim
- Department of Internal Medicine, Chuncheon Sacred Heart Hospital, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Choong Kee Park
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, Republic of Korea
| | - Eun-Kyoung Choi
- Department of Biomedical Gerontology, Graduate School of Hallym University, Anyang, Republic of Korea
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
- * E-mail: (MKJ); (EKC)
| | - Myoung-Kuk Jang
- Department of Internal Medicine, Kangdong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Republic of Korea
- * E-mail: (MKJ); (EKC)
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9
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Development of a fluorescent probe for detection of citrulline based on photo-induced electron transfer. Bioorg Med Chem Lett 2018; 28:969-973. [PMID: 29439901 DOI: 10.1016/j.bmcl.2018.01.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 01/13/2018] [Accepted: 01/16/2018] [Indexed: 01/11/2023]
Abstract
Peptidyl arginine deiminases (PADs) catalyze the post-translational deimination of peptidyl arginine residues to form citrulline residues. Aberrant citrullination of histones by one of the PAD isozymes, PAD4, is associated with various diseases, including rheumatoid arthritis, so high-throughput screening systems are needed to identify PAD4 inhibitors as chemical tools to investigate the role of PAD4, and as candidate therapeutic agents. Here, we utilized the addition-cyclization reaction between phenylglyoxal and citrulline under acidic conditions to design turn-on fluorescent probes for citrulline based on the donor-excited photoinduced electron transfer (d-PeT) mechanism. Among several derivatives of phenylglyoxal bearing a fluorescent moiety, we found that FGME enabled detection of citrulline without a neutralization process, and we used it to establish a simple methodology for turn-on fluorescence detection of citrulline.
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10
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Lange S, Gallagher M, Kholia S, Kosgodage US, Hristova M, Hardy J, Inal JM. Peptidylarginine Deiminases-Roles in Cancer and Neurodegeneration and Possible Avenues for Therapeutic Intervention via Modulation of Exosome and Microvesicle (EMV) Release? Int J Mol Sci 2017; 18:ijms18061196. [PMID: 28587234 PMCID: PMC5486019 DOI: 10.3390/ijms18061196] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 12/14/2022] Open
Abstract
Exosomes and microvesicles (EMVs) are lipid bilayer-enclosed structures released from cells and participate in cell-to-cell communication via transport of biological molecules. EMVs play important roles in various pathologies, including cancer and neurodegeneration. The regulation of EMV biogenesis is thus of great importance and novel ways for manipulating their release from cells have recently been highlighted. One of the pathways involved in EMV shedding is driven by peptidylarginine deiminase (PAD) mediated post-translational protein deimination, which is calcium-dependent and affects cytoskeletal rearrangement amongst other things. Increased PAD expression is observed in various cancers and neurodegeneration and may contribute to increased EMV shedding and disease progression. Here, we review the roles of PADs and EMVs in cancer and neurodegeneration.
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Affiliation(s)
- Sigrun Lange
- Department of Biomedical Sciences, University of Westminster, 115, New Cavendish Street, London W1W 6UW, UK.
- School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK.
| | - Mark Gallagher
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK.
| | - Sharad Kholia
- Molecular Biotechnology Center, Department of Medical Sciences, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy.
| | - Uchini S Kosgodage
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK.
| | - Mariya Hristova
- Institute for Women's Health, University College London, 74 Huntley Street, London WC1N 6HX, UK.
| | - John Hardy
- Reta Lila Weston Research Laboratories, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3BG, UK.
| | - Jameel M Inal
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, 166-220 Holloway Road, London N7 8DB, UK.
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11
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Sarswat A, Wasilewski E, Chakka SK, Bello AM, Caprariello AV, Muthuramu CM, Stys PK, Dunn SE, Kotra LP. Inhibitors of protein arginine deiminases and their efficacy in animal models of multiple sclerosis. Bioorg Med Chem 2017; 25:2643-2656. [PMID: 28341402 DOI: 10.1016/j.bmc.2017.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 02/28/2017] [Accepted: 03/03/2017] [Indexed: 11/25/2022]
Abstract
Protein arginine deiminases (PAD) are implicated in a variety of inflammatory and neurodegenerative diseases including multiple sclerosis (MS). Following the discovery of an in silico hit containing hydantoin and a piperidine moiety, we hypothesized that a 2-carbon linker on the hydantoin would be necessary for a 5-membered heterocycle for optimal PAD inhibitory activity. We designed thirteen compounds as potential inhibitors of PAD2 and PAD4 enzymes-two important PAD enzymes implicated in MS. Two compounds, one with an imidazole moiety (22) and the other with a tetrazole moiety (24) showed good inhibition of PAD isozymes in vitro and in the EAE mouse model of MS in vivo. Further experiments suggested that compound 22, a non-covalent inhibitor of PAD2 and PAD4, exhibits dose-dependent efficacy in the EAE mouse model and in the cuprizone-mediated demyelination model.
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Affiliation(s)
- Amit Sarswat
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Ewa Wasilewski
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada; Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario M5S 3M2, Canada
| | - Sai K Chakka
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Angelica M Bello
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada; Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario M5S 3M2, Canada
| | - Andrew V Caprariello
- Hotchkiss Brain Institute and Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Chithra M Muthuramu
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Peter K Stys
- Hotchkiss Brain Institute and Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Shannon E Dunn
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada; Department of Immunology, University of Toronto, and Women's College Research Institute, Toronto, Ontario, M5S 1B2, Canada
| | - Lakshmi P Kotra
- Centre for Molecular Design and Preformulations, and Division of Experimental Therapeutics, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada; Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Ontario M5S 3M2, Canada.
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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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Masutomi H, Kawashima S, Kondo Y, Uchida Y, Jang B, Choi EK, Kim YS, Shimokado K, Ishigami A. Induction of peptidylarginine deiminase 2 and 3 by dibutyryl cAMP via cAMP-PKA signaling in human astrocytoma U-251MG cells. J Neurosci Res 2016; 95:1503-1512. [PMID: 27704563 DOI: 10.1002/jnr.23959] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/30/2016] [Accepted: 09/12/2016] [Indexed: 12/16/2022]
Abstract
Peptidylarginine deiminases (PADs) are posttranslational modification enzymes that citrullinate (deiminate) protein arginine residues in a calcium-dependent manner, yielding citrulline residues. Enzymatic citrullination abolishes positive charges of native protein molecules, inevitably causing significant alterations in their structure and function. Previously, we reported the abnormal accumulation of citrullinated proteins and an increase of PAD2 content in hippocampi of patients with Alzheimer disease. In this study, we investigated PAD expression by using dibutyryl cAMP (dbcAMP) in human astrocytoma U-251MG cells. Under normal culture conditions, PAD2 and PAD3 mRNA expression is detectable with quantitative PCR in U-251MG cells. The addition of dbcAMP in a dose-dependent manner significantly increased this mRNA expression and protein levels. Moreover, PAD enzyme activity also increased significantly and dose-dependently. Furthermore, the expression of PAD2 and PAD3 mRNA was inhibited by the cAMP-dependent PKA inhibitor KT5720, suggesting that such expression of dbcAMP-induced PAD2 and PAD3 mRNA is mediated by the cAMP-PKA signaling pathway in U-251MG cells. This is the first report to document the PAD2 and PAD3 mRNA expression induced by dbcAMP and to attribute the induction of these genes to mediation by the cAMP-PKA signaling pathway in U-251MG cells. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Hirofumi Masutomi
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Geriatrics and Vascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Saki Kawashima
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Yoshitaka Kondo
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Yoshiaki Uchida
- Research & Development Division, Fujirebio Inc., Tokyo, Japan
| | - Byungki Jang
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, Gyeonggi-do, Korea
| | - Kentaro Shimokado
- Geriatrics and Vascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Akihito Ishigami
- Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Witalison EE, Thompson PR, Hofseth LJ. Protein Arginine Deiminases and Associated Citrullination: Physiological Functions and Diseases Associated with Dysregulation. Curr Drug Targets 2016; 16:700-10. [PMID: 25642720 DOI: 10.2174/1389450116666150202160954] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/24/2015] [Indexed: 11/22/2022]
Abstract
Human proteins are subjected to more than 200 known post-translational modifications (PTMs) (e.g., phosphorylation, glycosylation, ubiquitination, S-nitrosylation, methylation, Nacetylation, and citrullination) and these PTMs can alter protein structure and function with consequent effects on the multitude of pathways necessary for maintaining the physiological homeostasis. When dysregulated, however, the enzymes that catalyze these PTMs can impact the genesis of countless diseases. In this review, we will focus on protein citrullination, a PTM catalyzed by the Protein Arginine Deiminase (PAD) family of enzymes. Specifically, we will describe the roles of the PADs in both normal human physiology and disease. The development of PAD inhibitors and their efficacy in a variety of autoimmune disorders and cancer will also be discussed.
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Affiliation(s)
| | | | - Lorne J Hofseth
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy 770 Sumter St., Coker Life Sciences, Rm. 513C University of South Carolina Columbia, SC 29208.
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Ishigami A, Masutomi H, Handa S, Nakamura M, Nakaya S, Uchida Y, Saito Y, Murayama S, Jang B, Jeon YC, Choi EK, Kim YS, Kasahara Y, Maruyama N, Toda T. Mass spectrometric identification of citrullination sites and immunohistochemical detection of citrullinated glial fibrillary acidic protein in Alzheimer's disease brains. J Neurosci Res 2015; 93:1664-74. [DOI: 10.1002/jnr.23620] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/20/2015] [Accepted: 06/22/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Akihito Ishigami
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
| | - Hirofumi Masutomi
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
| | - Setsuko Handa
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
| | - Megumi Nakamura
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
| | - Shuuichi Nakaya
- Global Applications Development Center; Shimadzu Corp.; Kyoto Japan
| | - Yoshiaki Uchida
- Research & Development Division; Fujirebio Inc.; Tokyo Japan
| | - Yuko Saito
- Department of Neuropathology; Tokyo Metropolitan Institute of Gerontology; Itabashi-ku, Tokyo Japan
| | - Shigeo Murayama
- Department of Neuropathology; Tokyo Metropolitan Institute of Gerontology; Itabashi-ku, Tokyo Japan
| | - Byungki Jang
- Ilsong Institute of Life Science; Hallym University; Anyang Gyeonggi-do Korea
| | - Yong-Chul Jeon
- Ilsong Institute of Life Science; Hallym University; Anyang Gyeonggi-do Korea
| | - Eun-Kyoung Choi
- Ilsong Institute of Life Science; Hallym University; Anyang Gyeonggi-do Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science; Hallym University; Anyang Gyeonggi-do Korea
| | - Yasushi Kasahara
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
- Research & Development Division; Fujirebio Inc.; Tokyo Japan
| | - Naoki Maruyama
- Molecular Regulation of Aging; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan
| | - Tosifusa Toda
- Advanced Medical Research Center; Yokohama City University; Yokohama Japan
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Kholia S, Jorfi S, Thompson PR, Causey CP, Nicholas AP, Inal JM, Lange S. A novel role for peptidylarginine deiminases in microvesicle release reveals therapeutic potential of PAD inhibition in sensitizing prostate cancer cells to chemotherapy. J Extracell Vesicles 2015; 4:26192. [PMID: 26095379 PMCID: PMC4475687 DOI: 10.3402/jev.v4.26192] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 04/30/2015] [Accepted: 05/06/2015] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Protein deimination, defined as the post-translational conversion of protein-bound arginine to citrulline, is carried out by a family of 5 calcium-dependent enzymes, the peptidylarginine deiminases (PADs) and has been linked to various cancers. Cellular microvesicle (MV) release, which is involved in cancer progression, and deimination have not been associated before. We hypothesize that elevated PAD expression, observed in cancers, causes increased MV release in cancer cells and contributes to cancer progression. BACKGROUND We have previously reported that inhibition of MV release sensitizes cancer cells to chemotherapeutic drugs. PAD2 and PAD4, the isozymes expressed in patients with malignant tumours, can be inhibited with the pan-PAD-inhibitor chloramidine (Cl-am). We sought to investigate whether Cl-am can inhibit MV release and whether this pathway could be utilized to further increase the sensitivity of cancer cells to drug-directed treatment. METHODS Prostate cancer cells (PC3) were induced to release high levels of MVs upon BzATP stimulation of P2X7 receptors. Western blotting with the pan-protein deimination antibody F95 was used to detect a range of deiminated proteins in cells stimulated to microvesiculate. Changes in deiminated proteins during microvesiculation were revealed by immunoprecipitation and immunoblotting, and mass spectrometry identified deiminated target proteins with putative roles in microvesiculation. CONCLUSION We report for the first time a novel function of PADs in the biogenesis of MVs in cancer cells. Our results reveal that during the stimulation of prostate cancer cells (PC3) to microvesiculate, PAD2 and PAD4 expression levels and the deimination of cytoskeletal actin are increased. Pharmacological inhibition of PAD enzyme activity using Cl-am significantly reduced MV release and abrogated the deimination of cytoskeletal actin. We demonstrated that combined Cl-am and methotrexate (MTX) treatment of prostate cancer cells increased the cytotoxic effect of MTX synergistically. Refined PAD inhibitors may form part of a novel combination therapy in cancer treatment.
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Affiliation(s)
- Sharad Kholia
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK
| | - Samireh Jorfi
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK
| | - Paul R Thompson
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, USA
| | - Corey P Causey
- Department of Chemistry, University of North Florida, Jacksonville, FL, USA
| | - Anthony P Nicholas
- Department of Neurology, University of Alabama at Birmingham, Birmingham, VA, USA
- Birmingham VA Medical Center, Birmingham, AL, USA
| | - Jameel M Inal
- Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK;
| | - Sigrun Lange
- School of Pharmacy, University College London, London, UK;
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Ishigami A, Uchida Y, Miyazaki T, Handa S, Choi EK, Kim YS, Kasahara Y, Maruyama N. Two novel sandwich ELISAs identify PAD4 levels and PAD4 autoantibodies in patients with rheumatoid arthritis. Mod Rheumatol 2014. [DOI: 10.3109/s10165-012-0748-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Moelants EA, Mortier A, Van Damme J, Proost P, Loos T. Peptidylarginine deiminases: physiological function, interaction with chemokines and role in pathology. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 9:e227-314. [PMID: 24063741 DOI: 10.1016/j.ddtec.2012.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Peptidylarginine deiminases in citrullination, gene regulation, health and pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1126-35. [PMID: 23860259 DOI: 10.1016/j.bbagrm.2013.07.003] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 01/17/2023]
Abstract
Peptidylarginine deiminases are a family of enzymes that mediate post-translational modifications of protein arginine residues by deimination or demethylimination to produce citrulline. In vitro, the activity of PADs is dependent on calcium and reductive reagents carrying a free sulfhydryl group. The discovery that PAD4 can target both arginine and methyl-arginine for citrullination about 10years ago renewed our interest in studying this family of enzymes in gene regulation and their physiological functions. The deregulation of PADs is involved in the etiology of multiple human diseases, including cancers and autoimmune disorders. There is a growing effort to develop isoform specific PAD inhibitors for disease treatment. However, the regulation of the activity of PADs in vivo remains largely elusive, and we expect that much will be learned about the role of these enzymes in a normal life cycle and under pathology conditions.
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van Beers JJ, Zendman AJ, Raijmakers R, Stammen-Vogelzangs J, Pruijn GJ. Peptidylarginine deiminase expression and activity in PAD2 knock-out and PAD4-low mice. Biochimie 2013; 95:299-308. [DOI: 10.1016/j.biochi.2012.09.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 09/24/2012] [Indexed: 11/16/2022]
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Moscarello MA, Lei H, Mastronardi FG, Winer S, Tsui H, Li Z, Ackerley C, Zhang L, Raijmakers R, Wood DD. Inhibition of peptidyl-arginine deiminases reverses protein-hypercitrullination and disease in mouse models of multiple sclerosis. Dis Model Mech 2012; 6:467-78. [PMID: 23118341 PMCID: PMC3597028 DOI: 10.1242/dmm.010520] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Multiple sclerosis (MS) is the most common CNS-demyelinating disease of humans, showing clinical and pathological heterogeneity and a general resistance to therapy. We first discovered that abnormal myelin hypercitrullination, even in normal-appearing white matter, by peptidylarginine deiminases (PADs) correlates strongly with disease severity and might have an important role in MS progression. Hypercitrullination is known to promote focal demyelination through reduced myelin compaction. Here we report that 2-chloroacetamidine (2CA), a small-molecule, PAD active-site inhibitor, dramatically attenuates disease at any stage in independent neurodegenerative as well as autoimmune MS mouse models. 2CA reduced PAD activity and protein citrullination to pre-disease status. In the autoimmune models, disease induction uniformly induced spontaneous hypercitrullination with citrulline+ epitopes targeted frequently. 2CA rapidly suppressed T cell autoreactivity, clearing brain and spinal cord infiltrates, through selective removal of newly activated T cells. 2CA essentially prevented disease when administered before disease onset or before autoimmune induction, making hypercitrullination, and specifically PAD enzymes, a therapeutic target in MS models and thus possibly in MS.
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Affiliation(s)
- Mario A Moscarello
- Molecular Structure and Function, The Research Institute, Hospital For Sick Children, Toronto, ON M5G 1X8, Canada.
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Two novel sandwich ELISAs identify PAD4 levels and PAD4 autoantibodies in patients with rheumatoid arthritis. Mod Rheumatol 2012; 23:794-803. [PMID: 22986904 DOI: 10.1007/s10165-012-0748-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/10/2012] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The peptidylarginine deiminase 4 (PAD4) gene and PAD4 autoantibodies have been associated with rheumatoid arthritis (RA) and its pathogenesis. Therefore, methods for accurately determining their levels in the peripheral blood of these patients would be a diagnostic asset. The objective of our study was to adapt the enzyme-linked immunosorbent assay (ELISA) method for evaluating PAD4 levels in human blood. METHODS We prepared recombinant human (h)PAD1, -2, -3, and -4 proteins to develop mouse monoclonal antibodies specific to hPAD4. We then generated six monoclonal antibodies against hPAD4 and developed two new sandwich ELISA methods for evaluating hPAD4 and PAD4 autoantibodies in the peripheral blood from 32 patients with RA, ten patients with osteoarthrosis, and 20 healthy individuals. RESULTS The distribution of hPAD4 in the patients' plasma was determined. Two populations were identified: one group with high hPAD4 levels (>0.57 ng/mL) and a second group with near-zero levels (<0.1 ng/mL). Most patients approximating zero hPAD4 levels had PAD4 autoantibodies. In contrast, most of those with higher plasma hPAD4 levels did not have detectable PAD4 autoantibodies. CONCLUSION The combination of these sandwich ELISA methods may be a potentially beneficial clinical tool for diagnosing RA.
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Ireland JM, Unanue ER. Autophagy in antigen-presenting cells results in presentation of citrullinated peptides to CD4 T cells. ACTA ACUST UNITED AC 2011; 208:2625-32. [PMID: 22162830 PMCID: PMC3244027 DOI: 10.1084/jem.20110640] [Citation(s) in RCA: 187] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Citrullinated peptide presentation by DCs and macrophages is constitutive, whereas B cells present modified peptides only with autophagy induced by serum starvation or BCR ligation. Antibody responses to citrullinated self-proteins are found in autoimmunities, particularly in rheumatoid arthritis, where they serve as a diagnostic indicator. We show here that processing of the protein hen egg-white lysozyme (HEL) resulted in citrullination of peptides presented on class II MHC molecules by antigen-presenting cells. The presentation of the citrullinated peptides but not of the unmodified peptides was associated with autophagy. Dendritic cells (DCs), macrophages, and thymic DCs presented citrullinated peptides constitutively. Their treatment with 3-methyladenine (3MA) blocked presentation of citrullinated HEL peptides, but presentation of unmodified peptides was not affected. Presentation of citrullinated peptides was not detected on B cells or B lymphoma cells under normal culture conditions. In B cells, engagement of the B cell antigen receptor was required for presentation of the citrullinated peptides, also inhibited by 3MA. B lymphoma–expressing HEL cells presented citrullinated peptides only after brief serum starvation. This presentation was reduced by 3MA or by reduction in Atg5 expression. Presentation of the unmodified peptides was not changed. The findings indicate a linkage between autophagy and autoreactivity through the generation of this neo-epitope.
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Affiliation(s)
- Jamie M Ireland
- Department of Pathology and Immunology, School of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA
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Subcellular localization of peptidylarginine deiminase 2 and citrullinated proteins in brains of scrapie-infected mice: nuclear localization of PAD2 and membrane fraction-enriched citrullinated proteins. J Neuropathol Exp Neurol 2011; 70:116-24. [PMID: 21343880 DOI: 10.1097/nen.0b013e318207559e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Peptidylarginine deiminase (PAD) and citrullinated proteins have emerged as key molecules in various human diseases, but detailed subcellular localizations of PAD2 and citrullinated proteins are poorly mapped in brain under normal and pathologic conditions. We performed subcellular fractionation and electron microscopic analysis using brains of normal and scrapie-infected mice. Peptidylarginine deiminase 2 was abundantly present in cytosol and weakly in microsomal and mitochondrial fractions and expression in these fractions was higher in brains of scrapie-infected mice. Despite relatively low PAD2 expression, in microsomal and mitochondrial fractions, citrullinated proteins were present at high levels in these fractions in scrapie-infected brains. Surprisingly, increased PAD2 expression and accumulated citrullinated proteins were also found in nuclear fractions in scrapie-infected brains. By electron microscopy, PAD2 and citrullinated proteins in scrapie-infected brains were widely distributed in most cellular compartments including mitochondria, endoplasmic reticulum, glial filaments, nuclei, and Golgi apparatus in astrocytes and hippocampal neurons. Taken together, we report for the first time the nuclear localization of PAD2 and the detailed subcellular localization of PAD2 and of citrullinated proteins in scrapie-infected brains. Our findings suggest that different subcellular compartmentalization of PAD2 and citrullinated proteins may have different physiological roles in normal and neurodegenerative conditions.
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Lee HJ, Joo M, Abdolrasulnia R, Young DG, Choi I, Ware LB, Blackwell TS, Christman BW. Peptidylarginine deiminase 2 suppresses inhibitory {kappa}B kinase activity in lipopolysaccharide-stimulated RAW 264.7 macrophages. J Biol Chem 2010; 285:39655-62. [PMID: 20937835 DOI: 10.1074/jbc.m110.170290] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Peptidylarginine deiminases (PADs) are enzymes that convert arginine to citrulline in proteins. In this study, we examined PAD-mediated citrullination and its effect on pro-inflammatory activity in the macrophage cell line RAW 264.7. Citrullination of 45-65-kDa proteins was induced when cells were treated with lipopolysaccharide (LPS; 1 μg/ml). Protein citrullination was suppressed by the intracellular calcium chelator BAPTA/AM (30 μM). LPS treatment up-regulated COX-2 levels in cells. Interestingly, overexpressing PAD2 reduced LPS-mediated COX-2 up-regulation by 50%. PAD2 overexpression also reduced NF-κB activity, determined by NF-κB-driven luciferase activity. The effect of PAD2 on NF-κB activity was further examined by using HEK 293 cells transfected with NF-κB luciferase, IκB β/γ kinase (IKKβ/γ) subunits, and PAD2. IKKβ increased NF-κB activity, but this increase was markedly suppressed when PAD2 was present in cells. IKKβ-mediated NF-κB activation was further enhanced by IKKγ in the presence of calcium ionophore A23187. However, this stimulatory effect of IKKβ/γ was abolished by PAD2. Coimmunoprecipitation of cell lysates showed that IKKγ and PAD2 can coimmunoprecipitate in the presence of the Ca(2+) ionophore. IKKγ coimmunoprecipitated truncation mutants, PAD2(1-385) and PAD2(355-672). The substitution of Gln-358 (a putative ligand for Ca(2+) binding) with an Ala abolished coimmunoprecipitation. Conversely, PAD2 coimmunoprecipitated truncation mutants IKKγ(1-196) and IKKγ(197-419). In other experiments, treating RAW 264.7 cells with LPS induced citrullination in the immunoprecipitates of IKKγ. In vitro citrullination assay showed that incubation of purified PAD2 and IKKγ proteins in the presence of Ca(2+) citrullinated IKKγ. These results demonstrate that PAD2 interacts with IKKγ and suppresses NF-κB activity.
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Affiliation(s)
- Hye Jeong Lee
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Méchin MC, Sebbag M, Arnaud J, Nachat R, Foulquier C, Adoue V, Coudane F, Duplan H, Schmitt AM, Chavanas S, Guerrin M, Serre G, Simon M. Update on peptidylarginine deiminases and deimination in skin physiology and severe human diseases. Int J Cosmet Sci 2010; 29:147-68. [PMID: 18489346 DOI: 10.1111/j.1467-2494.2007.00377.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Deimination (or citrullination) is a recently described post-translational modification, but its consequences are not yet well understood. It is catalysed by peptidylarginine deiminases (PADs). These enzymes transform arginyl residues involved in a peptidyl link into citrullyl residues in a calcium-dependent manner. Several PAD substrates have already been identified like filaggrin and keratins K1 and K10 in the epidermis, trichohyalin in hair follicles, but also ubiquitous proteins like histones. PADs act in a large panel of physiological functions as cellular differentiation or gene regulation. It has been suggested that deimination plays a role in many major diseases such as rheumatoid arthritis, multiple sclerosis, Alzheimer's disease and psoriasis. Five human genes (PADIs), encoding five highly conserved paralogous enzymes (PAD1-4 and 6), have been characterized. These genes are clustered in a single locus, at 1p35-36 in man. Only PAD1-3 are expressed in human epidermis. PADs seem to be controlled at transcriptional, translational and activity levels and they present particular substrate specificities. In this review, we shall discuss these main biochemical, genetic and functional aspects of PADs together with their pathophysiological implications.
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Affiliation(s)
- M-C Méchin
- University of Toulouse III, UMR5165, Institut Fédératif de Recherche Claude de Préval, Toulouse, France.
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Ishigami A, Maruyama N. Importance of research on peptidylarginine deiminase and citrullinated proteins in age-related disease. Geriatr Gerontol Int 2010; 10 Suppl 1:S53-8. [DOI: 10.1111/j.1447-0594.2010.00593.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Shimada N, Handa S, Uchida Y, Fukuda M, Maruyama N, Asaga H, Choi EK, Lee J, Ishigami A. Developmental and age-related changes of peptidylarginine deiminase 2 in the mouse brain. J Neurosci Res 2010; 88:798-806. [PMID: 19830834 DOI: 10.1002/jnr.22255] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Peptidylarginine deiminases (PADs) are a group of posttranslational modification enzymes that citrullinate (deiminate) protein arginine residues in a Ca(2+)-dependent manner. Enzymatic citrullination abolishes positive charges of native protein molecules, inevitably causing significant alterations in their structure and functions. Among the five isoforms of PADs, PAD2 and PAD4 are proved occupants of the central nervous system (CNS), and especially PAD2 is a main PAD enzyme expressed in the CNS. We previously reported that abnormal protein citrullination by PAD2 has been closely associated with the pathogenesis of neurodegenerative disorders such as Alzheimer's disease and prion disease. Protein citrullination in these patients is thought to play a role during the initiation and/or progression of disease. However, the contribution of changes in PAD2 levels, and consequent citrullination, during developmental and aging processes remained unclear. Therefore, we used quantitative real-time RT-PCR, Western blot analysis, and immunohistochemical methods to measure PAD2 expression and localization in the brain during those processes. PAD2 mRNA expression was detected in the brains of mice as early as embryonic day 15, and its expression in cerebral cortex, hippocampus, and cerebellum increased significantly as the animals aged from 3 to 30 months old. No citrullinated proteins were detected during that period. Moreover, we found here, for the first time, that PAD2 localized specifically in the neuronal cells of the cerebral cortex and Purkinje cells of the cerebellum. These findings indicate that, despite PAD2's normally inactive status, it becomes active and citrullinates cellular proteins, but only when the intracellular Ca(2+) balance is upset during neurodegenerative changes.
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Affiliation(s)
- Nobuko Shimada
- Aging Regulation, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Tanikawa C, Ueda K, Nakagawa H, Yoshida N, Nakamura Y, Matsuda K. Regulation of protein Citrullination through p53/PADI4 network in DNA damage response. Cancer Res 2009; 69:8761-9. [PMID: 19843866 DOI: 10.1158/0008-5472.can-09-2280] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Upon a wide range of cellular stresses, p53 is activated and inhibits malignant transformation through the transcriptional regulation of its target genes related to apoptosis, cell cycle arrest, and DNA repair. However, its involvement in posttranslational modifications of proteins has not yet been well characterized. Here, we report the novel role of p53 in the regulation of protein citrullination. p53 transactivated peptidylarginine deiminase type 4 (PADI4) through an intronic p53-binding site. The PADI4 gene encodes an enzyme catalyzing the citrullination of arginine residues in proteins, and ectopic expression of p53 or PADI4 induced protein citrullination. In addition, various proteins were citrullinated in response to DNA damage, but knockdown of PADI4 or p53 remarkably inhibited their citrullination, indicating the regulation of protein citrullination in a p53/PADI4-dependent manner. We found that PADI4 citrullinated the histone chaperone protein, nucleophosmin (NPM1), at the arginine 197 residue in vivo under physiologic conditions. Citrullination of NPM1 by PADI4 resulted in its translocation from the nucleoli to the nucleoplasm, whereas PADI4 did not alter the localization of mutant NPM1 (R197K). Furthermore, ectopic expression of PADI4 inhibited tumor cell growth, and concordantly, the knockdown of PADI4 attenuated p53-mediated growth-inhibitory activity, demonstrating the significance of PADI4-mediated protein citrullination in the p53 signaling pathway
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Affiliation(s)
- Chizu Tanikawa
- Laboratory of Molecular Medicine, Human Genome Center, Division of Gene Expression and Regulation, Institute of Medical Science, the University of Tokyo, Japan
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Rebl A, Köllner B, Anders E, Wimmers K, Goldammer T. Peptidylarginine deiminase gene is differentially expressed in freshwater and brackish water rainbow trout. Mol Biol Rep 2009; 37:2333-9. [PMID: 19693695 DOI: 10.1007/s11033-009-9738-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 08/05/2009] [Indexed: 11/30/2022]
Abstract
Peptidylarginine deiminase (PADI)-like cDNA sequence was isolated from rainbow trout (Oncorhynchus mykiss). It consists of a 111-bp 5'-untranslated region, a 731-bp 3'-UTR, and a 2,010-bp open reading frame encoding a protein of 669 amino acids. In the presence of calcium ions, PADI enzymes catalyze the post-translational modification reaction generating citrulline residues. Mammalian PADI enzymes are involved in a number of regulatory processes during cell differentiation and development such as skin keratinization, myelin maturation, and histone deimination. Though five PADI isotypes have been isolated from mammals, in bony fish only one PADI enzyme is present, which contains conserved amino acid residues responsible for catalysis and calcium ion-binding. Sequence identity of piscine PADI protein sequences available at gene databases exceeds 67%. Phylogenetic analyses revealed that not only piscine, but also amphibian and avian PADI-like proteins share most identical amino acid residues with mammalian PADI2. mRNA level of trout PADI-like gene is high in skin, fin, gills, brain, and spleen of rainbow trout. Quantitative Real-Time RT-PCR revealed that PADI gene is differentially expressed in liver, trunk kidney, and spleen of two trout strains, the freshwater-cultured STEELHEAD trout and the brackish water strain BORN.
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Affiliation(s)
- Alexander Rebl
- Forschungsinstitut für die Biologie landwirtschaftlicher Nutztiere (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
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Increased expression of PAD2 after repeated intracerebroventricular infusions of soluble Abeta(25-35) in the Alzheimer's disease model rat brain: effect of memantine. Cell Mol Biol Lett 2009; 14:703-14. [PMID: 19641855 PMCID: PMC6275788 DOI: 10.2478/s11658-009-0029-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Accepted: 07/17/2009] [Indexed: 02/03/2023] Open
Abstract
Peptidylarginine deiminases (PADs) convert the arginine residues in proteins into citrulline residues in a Ca(2+)-dependent manner. We previously showed that a bilateral injection of ibotenic acid into the rat nucleus basalis magnocellularis elevated the PAD2 activity in the hippocampus and striatum. In this study, we examined whether repeated intracerebroventricular infusions of soluble Abeta25-35 would affect the PAD2 expression in any regions of the rat brain. We also assessed the protective effect of memantine on Abeta-induced PAD2 alterations. The infusion of Abeta(25-35) increased the activity and protein level of PAD2 in the hippocampus, and co-treatment with memantine suppressed these changes. An immunohistochemical analysis showed that an increased level of PAD2 was coincident with GFAP-positive astrocytes and CD11b-positive microglia. In addition, immunofluoresecence staining revealed that citrullinepostive immunoreactivity coincided with the occurrence of GFAP-positive astrocytes. Co-treatment with memantine reversed the activation of the astrocytes and microglia, thus attenuating the PAD2 increment. These biochemical and immunohistochemical results suggest that PAD2 might play an important role in the pathology of early Alzheimer's disease, and may correlate with the changes in glial cells that are recovered by memantine treatment.
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Abstract
Deimination is a posttranslational modification and refers to the conversion of protein bound arginine into citrulline. In the retina, deimination is predominantly catalyzed by Peptidylarginine deiminase type 2 (PAD2). PAD2 expression and deimination are found in many different retinal layers: choroid, retinal pigment epithelium (RPE), photoreceptors, inner plexiform layer, inner nuclear layer, and retinal ganglion cell (RGC) layer. Although decreased retinal deimination and PAD2 expression have been found during normal aging, elevated PAD2 expression and deimination have been observed in age-related neurodegenerative diseases. The role of deimination in normal physiology and in late-onset and progressive ocular or retinal degenerative diseases, such as glaucoma and experimental autoimmune encephalomyelitis remains to be elucidated.
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Hojo-Nakashima I, Sato R, Nakashima K, Hagiwara T, Yamada M. Dynamic Expression of Peptidylarginine Deiminase 2 in Human Monocytic Leukaemia THP-1 Cells During Macrophage Differentiation. J Biochem 2009; 146:471-9. [DOI: 10.1093/jb/mvp097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Musse AA, Li Z, Ackerley CA, Bienzle D, Lei H, Poma R, Harauz G, Moscarello MA, Mastronardi FG. Peptidylarginine deiminase 2 (PAD2) overexpression in transgenic mice leads to myelin loss in the central nervous system. Dis Model Mech 2008; 1:229-40. [PMID: 19093029 DOI: 10.1242/dmm.000729] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 08/12/2008] [Indexed: 11/20/2022] Open
Abstract
Demyelination in the central nervous system is the hallmark feature in multiple sclerosis (MS). The mechanism resulting in destabilization of myelin is a complex multi-faceted process, part of which involves deimination of myelin basic protein (MBP). Deimination, the conversion of protein-bound arginine to citrulline, is mediated by the peptidylarginine deiminase (PAD) family of enzymes, of which the PAD2 and PAD4 isoforms are present in myelin. To test the hypothesis that PAD contributes to destabilization of myelin in MS, we developed a transgenic mouse line (PD2) containing multiple copies of the cDNA encoding PAD2, under the control of the MBP promoter. Using previously established criteria, clinical signs were more severe in PD2 mice than in their normal littermates. The increase in PAD2 expression and activity in white matter was demonstrated by immunohistochemistry, reverse transcriptase-PCR, enzyme activity assays, and increased deimination of MBP. Light and electron microscopy revealed more severe focal demyelination and thinner myelin in the PD2 homozygous mice compared with heterozygous PD2 mice. Quantitation of the disease-associated molecules GFAP and CD68, as measured by immunoslot blots, were indicative of astrocytosis and macrophage activation. Concurrently, elevated levels of the pro-inflammatory cytokine TNF-alpha and nuclear histone deimination support initiation of demyelination by increased PAD activity. These data support the hypothesis that elevated PAD levels in white matter represents an early change that precedes demyelination.
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Affiliation(s)
- Abdiwahab A Musse
- Department of Molecular and Cellular Biology and Biophysics Interdepartmental Group, University of Guelph, Ontario, Canada N1G 2W1
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Louw C, Gordon A, Johnston N, Mollatt C, Bradley G, Whiteley CG. Arginine deiminases: Therapeutic tools in the etiology and pathogenesis of Alzheimer's disease. J Enzyme Inhib Med Chem 2008; 22:121-6. [PMID: 17373558 DOI: 10.1080/14756360600990829] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
There is, at present, no definitive pre-mortem diagnostic tool for Alzheimer's disease, (AD) which relates to a poor understanding of its etiology. Brains of AD patients contain large amounts of the toxic plaque-forming beta-amyloid1-42 fragment in addition to elevated concentrations of the amino acid L-arginine. This work proposes that lowering levels of arginine in the astrocytes surrounding amyloid plaques may serve as a therapeutic tool in this neurodegenerative disorder. Arginine deiminase (ADI), from Pseudomonas aeruginosa, and peptidylarginine deiminase [PAD II], from bovine brain, are inhibited by amyloid peptides that contain arginine (amyloid1-42) and those that have no arginine (amyloid12-28/22-35). Enhanced activity of PAD II is noted with free L-arginine.
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Affiliation(s)
- Cassandra Louw
- Department of Biochemistry, Microbiology and Biotechnology Rhodes University, Grahamstown, South Africa
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Musse AA, Polverini E, Raijmakers R, Harauz G. Kinetics of human peptidylarginine deiminase 2 (hPAD2) — Reduction of Ca2+ dependence by phospholipids and assessment of proposed inhibition by paclitaxel side chains. Biochem Cell Biol 2008; 86:437-47. [DOI: 10.1139/o08-124] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Multiple sclerosis is a complex human neurodegenerative disease, characterized by the active destruction of the insulating myelin sheath around the axons in the central nervous system. The physical deterioration of myelin is mediated by hyperdeimination of myelin basic and other proteins, catalysed by the Ca2+-dependent enzyme peptidylarginine deiminase 2 (PAD2). Thus, inhibition of PAD2 may be of value in treatment of this disease. Here, we have first characterized the in vitro kinetic properties of the human peptidylarginine deiminase isoform 2 (hPAD2). Phosphatidylserine and phosphatidylcholine reduced its Ca2+ dependence by almost twofold. Second, we have explored the putative inhibitory action of the methyl ester side chain of paclitaxel (TSME), which shares structural features with a synthetic PAD substrate, viz., the benzoyl-l-arginine ethyl ester (BAEE). Using the known crystallographic structure of the homologous enzyme hPAD4 and in silico molecular docking, we have shown that TSME interacted strongly with the catalytic site, albeit with a 100-fold lower affinity than BAEE. Despite paclitaxel having previously been shown to inhibit hPAD2 in vitro, the side chain of paclitaxel alone did not inhibit this enzyme’s activity.
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Affiliation(s)
- Abdiwahab A. Musse
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - Eugenia Polverini
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - Reinout Raijmakers
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | - George Harauz
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
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Jang B, Kim E, Choi JK, Jin JK, Kim JI, Ishigami A, Maruyama N, Carp RI, Kim YS, Choi EK. Accumulation of citrullinated proteins by up-regulated peptidylarginine deiminase 2 in brains of scrapie-infected mice: a possible role in pathogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1129-42. [PMID: 18787103 DOI: 10.2353/ajpath.2008.080388] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Peptidylarginine deiminases (PADs), which are a group of posttranslational modification enzymes, are involved in protein citrullination (deimination) by the conversion of peptidylarginine to peptidylcitrulline in a calcium concentration-dependent manner. Among the PADs, PAD2 is widely distributed in various tissues and is the only type that is expressed in brain. To elucidate the involvement of protein citrullination by PAD2 in the pathogenesis of brain-specific prion diseases, we examined the profiles of citrullinated proteins using the brains of scrapie-infected mice as a prion disease model. We found that, compared with controls, increased levels of citrullinated proteins of various molecular weights were detected in different brain sections of scrapie-infected mice. In support of this data, expression levels of PAD2 protein as well as its enzyme activity were significantly increased in brain sections of scrapie-infected mice, including hippocampus, brain stem, and striatum. Additionally, the expression levels of PAD2 mRNA were increased during scrapie infection. Moreover, PAD2 immunoreactivity was increased in scrapie-infected brains, with staining detected primarily in reactive astrocytes. Using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry, various citrullinated proteins were identified in the brains of scrapie-infected mice, including glial fibrillary acidic protein, myelin basic protein, enolases, and aldolases. This study suggests that accumulated citrullinated proteins and abnormal activation of PAD2 may function in the pathogenesis of prion diseases and serve as potential therapeutic targets.
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Affiliation(s)
- Byungki Jang
- Ilsong Institute of Life Science, Hallym University, Anyang, Republic of Korea
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Bhattacharya SK, Sinicrope B, Rayborn ME, Hollyfield JG, Bonilha VL. Age-related reduction in retinal deimination levels in the F344BN rat. Aging Cell 2008; 7:441-4. [PMID: 18248664 DOI: 10.1111/j.1474-9726.2008.00376.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Increased deimination and peptidyl arginine deiminase type 2 (PAD2) expression has been observed in age-related neurodegenerative diseases without discrimination between their aging and disease component. Here, we describe reduced levels of deimination commensurate with reduced protein, mRNA and activity of peptidylarginine deiminase type 2 in the retina, optic nerve and plasma of aged rats when compared to young rats. The decrease was significant in the ganglion cell layer, inner plexiform layer and inner nuclear layer. Because our observations suggest reduced deimination is a consequence of aging, we conclude that increased deimination must be a consequence of disease. Our findings are important to understand late-onset and progressive diseases such as glaucoma, pseudoexfoliation syndrome, age-related macular degeneration and Oguchi's disease.
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Affiliation(s)
- Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, 1638 NW 10th Avenue, 706, University of Miami, Miami, FL 33136, USA.
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Zendman AJW, Raijmakers R, Nijenhuis S, Vossenaar ER, Tillaart MVD, Chirivi RGS, Raats JMH, van Venrooij WJ, Drijfhout JW, Pruijn GJM. ABAP: Antibody-based assay for peptidylarginine deiminase activity. Anal Biochem 2007; 369:232-40. [PMID: 17716614 DOI: 10.1016/j.ab.2007.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 07/04/2007] [Accepted: 07/11/2007] [Indexed: 11/17/2022]
Abstract
Members of the family of peptidylarginine deiminases (PADs, EC 3.5.3.15) catalyze the posttranslational modification of peptidylarginine into peptidylcitrulline. Citrulline-containing epitopes have been shown to be major and specific targets of autoantibodies produced by rheumatoid arthritis patients. Recently, the citrullination of histone proteins by PAD enzyme was reported to influence gene expression levels. These findings greatly increase the interest in the PAD enzymes and their activities. A few procedures to monitor PAD activity in biological samples have been described previously. However, these assays either have low sensitivity or are rather laborious. Here we describe a reliable and reproducible method for the determination of PAD activity in both purified and crude samples. The method is based on the quantification of PAD-dependent citrullination of peptides, immobilized in microtiter plates, using antibodies that are exclusively reactive with the reaction product(s). Our results demonstrate that this antibody-based assay for PAD activity, called ABAP, is very sensitive and can be applied to monitor PAD activity in biological samples.
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Affiliation(s)
- Albert J W Zendman
- Department of Biomolecular Chemistry, Nijmegen Center for Molecular Life Sciences, Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen NL-6500 HB, The Netherlands
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Asaga H, Ishigami A. Microglial expression of peptidylarginine deiminase 2 in the prenatal rat brain. Cell Mol Biol Lett 2007; 12:536-44. [PMID: 17579814 PMCID: PMC6275991 DOI: 10.2478/s11658-007-0025-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 04/18/2007] [Indexed: 11/20/2022] Open
Abstract
Peptidylarginine deiminases (PADs) are Ca2t+-dependant post-translational modification enzymes that catalyze the citrullination of protein arginyl residues. PAD type 2 (PAD2) is thought to be involved in some processes of neurodegeneration and myelination in the central nervous system. In this study, we found PAD2-positive cells in rat cerebra in 19-to 21-day old embryos, i.e. at a developmental stage well before myelination begins. Most of the cells were microglial marker-positive cells found mainly in the prospective medulla, and others were microglial marker-negative cells found mainly in the prospective dentate gyrus of the hippocampus. The former seemed to be in an activated state as judged by morphological criteria. The specificity of the enzyme activity, immunoblotting and reverse transcriptase-polymerase chain reaction analyses revealed that these cells expressed PAD2 and not PAD1, PAD3 or PAD4. Our data is indicative of microglial expression of PAD2 in the prenatal developing cerebrum.
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Affiliation(s)
- Hiroaki Asaga
- Biological Science Laboratory, Meiji University, Suginami-ku, Tokyo, 168-8555, Japan.
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Harauz G, Musse AA. A Tale of Two Citrullines—Structural and Functional Aspects of Myelin Basic Protein Deimination in Health and Disease. Neurochem Res 2006; 32:137-58. [PMID: 16900293 DOI: 10.1007/s11064-006-9108-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2006] [Indexed: 02/03/2023]
Abstract
Myelin basic protein (MBP) binds to negatively charged lipids on the cytosolic surface of oligodendrocyte membranes and is responsible for adhesion of these surfaces in the multilayered myelin sheath. The pattern of extensive post-translational modifications of MBP is dynamic during normal central nervous system (CNS) development and during myelin degeneration in multiple sclerosis (MS), affecting its interactions with the myelin membranes and with other molecules. In particular, the degree of deimination (or citrullination) of MBP is correlated with the severity of MS, and may represent a primary defect that precedes neurodegeneration due to autoimmune attack. That the degree of MBP deimination is also high in early CNS development indicates that this modification plays major physiological roles in myelin assembly. In this review, we describe the structural and functional consequences of MBP deimination in healthy and diseased myelin.
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Affiliation(s)
- George Harauz
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, Canada, N1G 2W1.
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Kuhn KA, Kulik L, Tomooka B, Braschler KJ, Arend WP, Robinson WH, Holers VM. Antibodies against citrullinated proteins enhance tissue injury in experimental autoimmune arthritis. J Clin Invest 2006; 116:961-73. [PMID: 16585962 PMCID: PMC1421345 DOI: 10.1172/jci25422] [Citation(s) in RCA: 384] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 01/03/2006] [Indexed: 11/17/2022] Open
Abstract
Antibodies against citrullinated proteins are specific and predictive markers for rheumatoid arthritis although the pathologic relevance of these antibodies remains unclear. To investigate the significance of these autoantibodies, collagen-induced arthritis (CIA) in mice was used to establish an animal model of antibody reactivity to citrullinated proteins. DBA/1J mice were immunized with bovine type II collagen (CII) at days 0 and 21, and serum was collected every 7 days for analysis. Antibodies against both CII and cyclic citrullinated peptide, one such citrullinated antigen, appeared early after immunization, before joint swelling was observed. Further, these antibodies demonstrated specific binding to citrullinated filaggrin in rat esophagus by indirect immunofluorescence and citrullinated fibrinogen by Western blot. To evaluate the role of immune responses to citrullinated proteins in CIA, mice were tolerized with a citrulline-containing peptide, followed by antigen challenge with CII. Tolerized mice demonstrated significantly reduced disease severity and incidence compared with controls. We also identified novel murine monoclonal antibodies specific to citrullinated fibrinogen that enhanced arthritis when coadministered with a submaximal dose of anti-CII antibodies and bound targets within the inflamed synovium of mice with CIA. These results demonstrate that antibodies against citrullinated proteins are centrally involved in the pathogenesis of autoimmune arthritis.
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Affiliation(s)
- Kristine A. Kuhn
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - Liudmila Kulik
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - Beren Tomooka
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - Kristin J. Braschler
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - William P. Arend
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - William H. Robinson
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
| | - V. Michael Holers
- Department of Immunology and
Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Geriatric Research, Education and Clinical Center, Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA
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Holm A, Rise F, Sessler N, Sollid LM, Undheim K, Fleckenstein B. Specific modification of peptide-bound citrulline residues. Anal Biochem 2006; 352:68-76. [PMID: 16540076 DOI: 10.1016/j.ab.2006.02.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 01/27/2006] [Accepted: 02/04/2006] [Indexed: 11/23/2022]
Abstract
Immune reactions to citrulline-containing proteins appear to be central in the immunopathogenesis of rheumatoid arthritis. Citrulline residues are introduced into proteins by deimination of arginine residues, likely by an enzymatic process. There is a need to characterize which proteins in the inflamed joints of rheumatoid patients contain citrulline in situ. The characterization of deiminated proteins will be greatly facilitated by specific modification of peptide-bound citrulline residues that will enable specific enrichment and detection of citrulline-containing peptides. This study presents the details of such a modification method. The chemistry behind the reaction of the ureido group of citrulline with 2,3-butanedione in the presence of antipyrine is unraveled. Parameters for optimization of the reaction with respect to specificity and completeness, including the testing of different acids, reactant concentrations, and reaction time, are presented. This modification reaction is specific for citrulline residues. The modified product shows a characteristic mass shift of +238Da, as demonstrated by mass spectrometry. The product absorbs UV-Vis radiation at 464nm, and it is demonstrated that this can be used to selectively monitor citrulline-containing peptides during the separation of protein digests. Finally, the structure of the product of modified citrulline is solved by nuclear magnetic resonance spectroscopy using N-butylurea as a model substance. The results presented should facilitate the development of tags that can be used for the enrichment and subsequent detection of citrulline-containing protein fragments by mass spectrometry.
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Affiliation(s)
- Anders Holm
- Institute of Immunology, University of Oslo, NO-0027 Oslo, Norway.
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44
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György B, Tóth E, Tarcsa E, Falus A, Buzás EI. Citrullination: a posttranslational modification in health and disease. Int J Biochem Cell Biol 2006; 38:1662-77. [PMID: 16730216 DOI: 10.1016/j.biocel.2006.03.008] [Citation(s) in RCA: 338] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 03/13/2006] [Accepted: 03/14/2006] [Indexed: 11/29/2022]
Abstract
Posttranslational modifications are chemical changes to proteins that take place after synthesis. One such modification, peptidylarginine to peptidylcitrulline conversion, catalysed by peptidylarginine deiminases, has recently received significant interest in biomedicine. Introduction of citrulline dramatically changes the structure and function of proteins. It has been implicated in several physiological and pathological processes. Physiological processes include epithelial terminal differentiation, gene expression regulation, and apoptosis. Rheumatoid arthritis, multiple sclerosis, and Alzheimer's disease are examples of human diseases where protein citrullination involvement has been demonstrated. In this review, we discuss our current understanding on the importance of protein deimination in these processes. We describe the enzymes catalyzing the reaction, as well as their known protein substrates. We review the citrullinated peptide epitopes that are proposed as disease markers, specifically recognized in certain human autoimmune disorders. The potential autopathogenic role of citrullinated epitopes is also discussed.
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Affiliation(s)
- Bence György
- Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary
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45
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Okazaki Y, Suzuki A, Sawada T, Ohtake-Yamanaka M, Inoue T, Hasebe T, Yamada R, Yamamoto K. Identification of citrullinated eukaryotic translation initiation factor 4G1 as novel autoantigen in rheumatoid arthritis. Biochem Biophys Res Commun 2006; 341:94-100. [PMID: 16412378 DOI: 10.1016/j.bbrc.2005.12.160] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 12/26/2005] [Indexed: 10/25/2022]
Abstract
Antibodies against citrullinated proteins are highly specific for rheumatoid arthritis. We previously reported that functional variants of the gene encoding peptidylarginine deiminase type 4 were closely associated with RA. The purpose of this study was to investigate the citrullinated autoantigens recognized by serum samples from patients with RA. The human chondrocyte cDNA expression library was citrullinated by PADI4 and was immunoscreened with anti-modified citrulline antibodies and sera from patients with rheumatoid arthritis. One immunoreactive cDNA clone containing a 2480-base pair insert was isolated and sequence analysis revealed that the cDNA included a part of the eukaryotic translation initiation factor 4G1. Immunoreactivity against a recombinant citrullinated eIF4G1 fragment was observed with high specificity in 50.0% of RA patients. The levels of antibodies against citrullinated eIF4G1 were correlated with those of anti-CCP antibodies. Citrullinated eIF4G1 was identified as a candidate citrullinated autoantigen in RA patients. Citrullination of eIF4G1 may thus be involved in the pathogenesis of RA.
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Affiliation(s)
- Yuko Okazaki
- Department of Allergy and Rheumatology, Graduate School of Medicine, The University of Tokyo, Japan
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46
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Feng D, Imasawa T, Nagano T, Kikkawa M, Takayanagi K, Ohsawa T, Akiyama K, Ishigami A, Toda T, Mitarai T, Machida T, Maruyama N. Citrullination preferentially proceeds in glomerular Bowman's capsule and increases in obstructive nephropathy. Kidney Int 2005; 68:84-95. [PMID: 15954898 DOI: 10.1111/j.1523-1755.2005.00383.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Peptidylarginine deiminases (PADs) are a group of posttranslational modification enzymes that citrullinate (deiminate) protein arginine residues, yielding citrulline residues. Citrullination of arginine residues abolishes their positive charge, markedly altering their structure. We undertook this study to investigate the actions of PADs in the kidney. METHODS In male rats, we ligated the unilateral ureter, then analyzed the obstructed and contralateral kidneys 1 week later. Controls were rats simultaneously given sham operations. In another experiment, we ligated unilateral ureters of eight rats, four of which received a ureter-bladder anastomosis 1 week later. These rats were subjected to histologic examinations 5 weeks after unilateral ureteral obstruction (UUO). RESULTS Reverse transcription-polymerase chain reaction (RT-PCR) revealed that, of PADs (type I, II, III, and IV), only PAD type II was expressed in kidneys. Western blot study showed that PAD type II expression and citrullinated protein content increased greatly in kidneys that underwent unilateral ureteral ligation compared to that in contralateral or sham-operated kidneys. Immunohistochemical analyses revealed that PAD type II was preferentially expressed by parietal epithelial cells and that only in Bowman's capsule were proteins citrullinated. Additionally, these PAD type II and citrullinated proteins in obstructed nephropathy were significantly attenuated by the release of the obstruction. Proteome analysis revealed that one of citrullinated proteins in the kidney should be actin. CONCLUSION This result indicates that PAD type II and citrullinated proteins are suitable markers of Bowman's capsule. Not only are these markers preferentially expressed in Bowman's capsules but their expression is also increased in damaged kidneys by UUO, features that promise the further clarification of kidney diseases.
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Affiliation(s)
- Dongyun Feng
- Department of Molecular Pathology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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47
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Ishigami A, Ohsawa T, Hiratsuka M, Taguchi H, Kobayashi S, Saito Y, Murayama S, Asaga H, Toda T, Kimura N, Maruyama N. Abnormal accumulation of citrullinated proteins catalyzed by peptidylarginine deiminase in hippocampal extracts from patients with Alzheimer's disease. J Neurosci Res 2005; 80:120-8. [PMID: 15704193 DOI: 10.1002/jnr.20431] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Citrullinated proteins are the products of a posttranslational process in which arginine residues undergo modification into citrulline residues when catalyzed by peptidylarginine deiminases (PADs) in a calcium ion-dependent manner. In our previous report, PAD2 expressed mainly in the rat cerebrum became activated early in the neurodegenerative process. To elucidate the involvement of protein citrullination in human neuronal degeneration, we examined whether citrullinated proteins are produced during Alzheimer's disease (AD). By Western blot analysis with antimodified citrulline antibody, citrullinated proteins of varied molecular weights were detected in hippocampal tissues from patients with AD but not normal humans. Two of the citrullinated proteins were identified as vimentin and glial fibrillary acidic protein (GFAP) by using two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Interestingly, PAD2 was detected in hippocampal extracts from AD and normal brains, but the amount of PAD2 in the AD tissue was markedly greater. Histochemical analysis revealed citrullinated proteins throughout the hippocampus, especially in the dentate gyrus and stratum radiatum of CA1 and CA2 areas. However, no citrullinated proteins were detected in the normal hippocampus. PAD2 immunoreactivity was also ubiquitous throughout both the AD and the normal hippocampal areas. PAD2 enrichment coincided well with citrullinated protein positivity. Double immunofluorescence staining revealed that citrullinated protein- and PAD2-positive cells also coincided with GFAP-positive cells, but not all GFAP-positive cells were positive for PAD2. As with GFAP, which is an astrocyte-specific marker protein, PAD2 is distributed mainly in astrocytes. These collective results, the abnormal accumulation of citrullinated proteins and abnormal activation of PAD2 in hippocampi of patients with AD, strongly suggest that PAD has an important role in the onset and progression of AD and that citrullinated proteins may become a useful marker for human neurodegenerative diseases.
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Affiliation(s)
- Akihito Ishigami
- Department of Molecular Pathology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
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Nijenhuis S, Zendman AJW, Vossenaar ER, Pruijn GJM, vanVenrooij WJ. Autoantibodies to citrullinated proteins in rheumatoid arthritis: clinical performance and biochemical aspects of an RA-specific marker. Clin Chim Acta 2005; 350:17-34. [PMID: 15530456 DOI: 10.1016/j.cccn.2004.07.016] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Revised: 06/30/2004] [Accepted: 07/15/2004] [Indexed: 12/01/2022]
Abstract
Rheumatoid arthritis (RA) is a common, systemic autoimmune disease of which the exact etiology is not known. In the past 10 years, substantial progress has been made in the identification of the antigens specifically recognized by the autoantibodies of RA patients. A central factor in this respect is citrullination, a form of post-translational modification that is strongly associated with autoimmunity in RA. Here, we summarize and discuss our current knowledge on (i) autoantibody systems in RA, (ii) the occurrence of peptidylarginine deiminases and (iii) citrullinated proteins in natural and diseased environments, and (iv) genetic factors involved in RA that may influence the generation and presentation of citrullinated proteins and the resulting antibody production against these modified proteins. Citrullination of proteins may play a key role in the initiation and/or the progression of RA. The onset of citrulline-specific autoimmunity in RA is probably mediated by both environmental and genetic factors, and future studies will learn whether therapeutic intervention at the level of citrullination may provide new possibilities to treat RA.
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Affiliation(s)
- Suzanne Nijenhuis
- Department of Biochemistry 161, Radboud University Nijmegen, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands
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49
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Lundberg K, Nijenhuis S, Vossenaar ER, Palmblad K, van Venrooij WJ, Klareskog L, Zendman AJW, Harris HE. Citrullinated proteins have increased immunogenicity and arthritogenicity and their presence in arthritic joints correlates with disease severity. Arthritis Res Ther 2005; 7:R458-67. [PMID: 15899032 PMCID: PMC1174941 DOI: 10.1186/ar1697] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 12/16/2004] [Accepted: 01/20/2005] [Indexed: 01/14/2023] Open
Abstract
Autoantibodies directed against citrulline-containing proteins have an impressive specificity of nearly 100% in patients with rheumatoid arthritis and have been suggested to be involved in the disease pathogenesis. The targeted epitopes are generated by a post-translational modification catalysed by the calcium-dependent enzyme peptidyl arginine deiminase (PAD), which converts positively charged arginine to polar but uncharged citrulline. The aim of this study was to explore the effects of citrullination on the immunogenicity of autoantigens as well as on potential arthritogenicity. Thus, immune responses to citrullinated rat serum albumin (Cit-RSA) and to unmodified rat serum albumin (RSA) were examined as well as arthritis development induced by immunisation with citrullinated rat collagen type II (Cit-CII) or unmodified CII. In addition, to correlate the presence of citrullinated proteins and the enzyme PAD4 with different stages of arthritis, synovial tissues obtained at different time points from rats with collagen-induced arthritis were examined immunohistochemically. Our results demonstrate that citrullination of the endogenous antigen RSA broke immunological tolerance, as was evident by the generation of antibodies directed against the modified protein and cross-reacting with the native protein. Furthermore we could demonstrate that Cit-CII induced arthritis with higher incidence and earlier onset than did the native counterpart. Finally, this study reveals that clinical signs of arthritis precede the presence of citrullinated proteins and the enzyme PAD4. As disease progressed into a more severe and chronic state, products of citrullination appeared specifically in the joints. Citrullinated proteins were detected mainly in extracellular deposits but could also be found in infiltrating cells and on the cartilage surface. PAD4 was detected in the cytoplasm of infiltrating mononuclear cells, from day 21 after immunisation and onwards. In conclusion, our data reveal the potency of citrullination to break tolerance against the self antigen RSA and to increase the arthritogenic properties of the cartilage antigen CII. We also show that citrullinated proteins and the enzyme PAD4 are not detectable in healthy joints, and that the appearance and amounts in arthritic joints of experimental animals are correlated with the severity of inflammation.
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Affiliation(s)
- Karin Lundberg
- Rheumatology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Suzanne Nijenhuis
- Department of Biochemistry, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Erik R Vossenaar
- Department of Biochemistry, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Karin Palmblad
- Rheumatology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Lars Klareskog
- Rheumatology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - AJW Zendman
- Department of Biochemistry, Radboud University Nijmegen, Nijmegen, The Netherlands
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50
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Sambandam T, Belousova M, Accaviti-Loper MA, Blanquicett C, Guercello V, Raijmakers R, Nicholas AP. Increased peptidylarginine deiminase type II in hypoxic astrocytes. Biochem Biophys Res Commun 2004; 325:1324-9. [PMID: 15555572 DOI: 10.1016/j.bbrc.2004.10.173] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Indexed: 10/26/2022]
Abstract
Peptidylarginine deiminase type II (PAD 2) is the primary enzyme responsible for conversion of protein bound arginine to citrulline in the central nervous system. Evidence suggests that glial fibrillary acidic protein (GFAP), the main intermediate filament in astrocytes, is deiminated, but not much is known regarding factors that control this enzymatic reaction. The present study demonstrated that PAD 2 activity (as determined by Western blot analysis of citrullinated GFAP isoforms) was increased in human cultured astrocytes by hypoxic conditions. PAD 2 mRNA increased markedly during the first 2h of hypoxia, but using a single chain antibody against human PAD 2 produced from the ETH-2 phage library, it took approximately 8h of hypoxia to see marked increases in PAD 2 protein. Thus, this is the first report to demonstrate a measurable response in the amounts of PAD 2 mRNA, protein and activity in human astrocytes by prolonged hypoxic exposure.
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Affiliation(s)
- Thiagarajan Sambandam
- Department of Neurology, University of Alabama at Birmingham, School of Medicine, Birmingham, AL 35294, USA
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