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Ji N, Chen Z, Wang Z, Sun W, Yuan Q, Zhang X, Jia X, Wu J, Jiang J, Song M, Xu T, Liu Y, Ma Q, Sun Z, Bao Y, Zhang M, Huang M. LincR-PPP2R5C Promotes Th2 Cell Differentiation Through PPP2R5C/PP2A by Forming an RNA-DNA Triplex in Allergic Asthma. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2024; 16:71-90. [PMID: 38262392 PMCID: PMC10823138 DOI: 10.4168/aair.2024.16.1.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 08/13/2023] [Accepted: 08/22/2023] [Indexed: 01/25/2024]
Abstract
PURPOSE The roles and mechanisms of long noncoding RNAs (lncRNAs) in T helper 2 (Th2) differentiation from allergic asthma are poorly understood. We aimed to explore a novel lncRNA, LincR-protein phosphatase 2 regulatory subunit B' gamma (PPP2R5C), in Th2 differentiation in a mouse model of asthma. METHODS LincR-PPP2R5C from RNA-seq data of CD4+ T cells of asthma-like mice were validated and confirmed by quantitative reverse transcription polymerase chain reaction, northern blotting, nuclear and cytoplasmic separation, and fluorescence in situ hybridization (FISH). Lentiviruses encoding LincR-PPP2R5C or shRNA were used to overexpress or silence LincR-PPP2R5C in CD4+ T cells. The interactions between LincR-PPP2R5C and PPP2R5C were explored with western blotting, chromatin isolation by RNA purification assay, and fluorescence resonance energy transfer. An ovalbumin-induced acute asthma model in knockout (KO) mice (LincR-PPP2R5C KO, CD4 conditional LincR-PPP2R5C KO) was established to explore the roles of LincR-PPP2R5C in Th2 differentiation. RESULTS LncR-PPP2R5C was significantly higher in CD4+ T cells from asthmatic mice ex vivo and Th2 cells in vitro. The lentivirus encoding LincR-PPP2R5C suppressed Th1 differentiation; in contrast, the short hairpin RNA (shRNA) lentivirus decreased LincR-PPP2R5C and Th2 differentiation. Mechanistically, LincR-PPP2R5C deficiency suppressed the phosphatase activity of the protein phosphatase 2A (PP2A) holocomplex, resulting in a decline in Th2 differentiation. The formation of an RNA-DNA triplex between LincR-PPP2R5C and the PPP2R5C promoter enhanced PPP2R5C expression and activated PP2A. LincR-PPP2R5C KO and CD4 conditional KO decreased Th2 differentiation, airway hyperresponsiveness and inflammatory responses. CONCLUSIONS LincR-PPP2R5C regulated PPP2R5C expression and PP2A activity by forming an RNA-DNA triplex with the PPP2R5C promoter, leading to Th2 polarization in a mouse model of acute asthma. Our data presented the first definitive evidence of lncRNAs in the regulation of Th2 cells in asthma.
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Affiliation(s)
- Ningfei Ji
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongqi Chen
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhengxia Wang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Sun
- Department of Respiratory and Critical Care Medicine, Xishan People's Hospital of Wuxi City, Wuxi Branch of Zhongda Hospital Affiliate to Southeast University, Wuxi, China
| | - Qi Yuan
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xijie Zhang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xinyu Jia
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingjing Wu
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingxian Jiang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Meijuan Song
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Tingting Xu
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yanan Liu
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qiyun Ma
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhixiao Sun
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yanmin Bao
- Department of Respiratory Medicine, Shenzhen Children's Hospital, Shenzhen, China
| | - Mingshun Zhang
- Jiangsu Province Engineering Research Center of Antibody Drugs, NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China.
| | - Mao Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
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Wu J, Xu J, Naguib M, Bie B. Blockade of Type 2A Protein Phosphatase Signaling Attenuates Complement C1q-Mediated Microglial Phagocytosis of Glutamatergic Synapses Induced by Amyloid Fibrils. Mol Neurobiol 2023; 60:1527-1536. [PMID: 36515857 PMCID: PMC9910161 DOI: 10.1007/s12035-022-03161-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022]
Abstract
We previously reported the critical involvement of metabotropic GluR1 (mGluR1) signaling in complement C1q-dependent microglial phagocytosis of glutamatergic synapses in a rat model of Alzheimer's disease (AD) injected with amyloid fibrils. Here, we explored the role of type 2A protein phosphatase (type 2A PPase), a key enzyme downstream of mGluR1 signaling, in the pathogenesis of AD in rats. Significant local upregulation of PP2A expression was observed in the hippocampal CA1 after bilateral microinjection of amyloid-beta (Aβ1-40) fibrils. Amyloid fibrils induced remarkable dephosphorylation of pFMRP (fragile X mental retardation protein) and C1q upregulation in hippocampal glutamatergic synapses, which was ameliorated by microinjection of type 2A PPase inhibitor okadaic acid (OA). Microinjection of OA further attenuated the microglial phagocytosis of glutamatergic synapses, recovered the hippocampal glutamatergic transmission, and improved the performance in Morris water maze test. These findings demonstrated that dysfunction of type 2A PPase signaling contributed to complement C1q-dependent microglial phagocytosis of glutamatergic synapses and the cognitive impairments in the rat model of AD.
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Affiliation(s)
- Jiang Wu
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Jijun Xu
- Department of Pain Management, Anesthesiology Institute, 9500 Euclid Ave, Cleveland, OH, 44195, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Mohamed Naguib
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Bihua Bie
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA.
- Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA.
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Hach T, Shakeri-Nejad K, Bigaud M, Dahlke F, de Micco M, Petricoul O, Graham G, Piani-Meier D, Turrini R, Brinkmann V, Nicoletti F. Rationale for Use of Sphingosine-1-Phosphate Receptor Modulators in COVID-19 Patients: Overview of Scientific Evidence. J Interferon Cytokine Res 2022. [DOI: 10.1089/jir.2022.0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Thomas Hach
- Patient Engagement, Novartis Pharma AG, Basel, Switzerland
| | - Kasra Shakeri-Nejad
- Department of Clinical Pharmacology; Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Marc Bigaud
- Department of Autoimmunity, Transplantation & Inflammation; Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Frank Dahlke
- Patient Engagement, Novartis Pharma AG, Basel, Switzerland
| | | | - Olivier Petricoul
- Department of Neuroscience; Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Gordon Graham
- Patient Engagement, Novartis Pharma AG, Basel, Switzerland
| | | | - Renato Turrini
- Department of Autoimmunity, Transplantation & Inflammation; Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University Sapienza of Rome, Rome, Italy
- Department of Molecular Neuropharmacology, IRCCS Neuromed, Pozzilli, Italy
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4
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Ghosh S, Rihan M, Ahmed S, Pande AH, Sharma SS. Immunomodulatory potential of apolipoproteins and their mimetic peptides in asthma: Current perspective. Respir Med 2022; 204:107007. [DOI: 10.1016/j.rmed.2022.107007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/03/2022] [Indexed: 10/31/2022]
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5
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Evaluation of okadaic acid toxicity in human retinal cells and zebrafish retinas. Toxicology 2022; 473:153209. [DOI: 10.1016/j.tox.2022.153209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/04/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022]
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Chen S, Chen L, Ye L, Jiang Y, Li Q, Zhang H, Zhang R, Li H, Yu D, Zhang R, Niu Y, Zhao Q, Liu J, Ouyang G, Aschner M, Zheng Y, Zhang L, Chen W, Li D. PP2A-mTOR-p70S6K/4E-BP1 axis regulates M1 polarization of pulmonary macrophages and promotes ambient particulate matter induced mouse lung injury. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127624. [PMID: 34740159 DOI: 10.1016/j.jhazmat.2021.127624] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/10/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
To identify key signaling pathways involved in ambient particulate matter (PM)-induced pulmonary injury, we generated a mouse model with myeloid-specific deletion of Ppp2r1a gene (encoding protein phosphatase 2 A (PP2A) A subunit), and conducted experiments in a real-ambient PM exposure system. PP2A Aα-/- homozygote (Aα HO) mice and matched wild-type (WT) littermates were exposed to PM over 3-week and 6-week. The effects of PM exposure on pulmonary inflammation, oxidative stress, and apoptosis were significantly enhanced in Aα HO compared to WT mice. The number of pulmonary macrophages increased by 74.8~88.0% and enhanced M1 polarization appeared in Aα HO mice upon PM exposure. Secretion of M1 macrophage-related inflammatory cytokines was significantly increased in Aα HO vs. WT mice following PM exposure. Moreover, we demonstrated that PP2A-B56α holoenzyme regulated M1 polarization and that the mTOR signaling pathway mediated the persistent M1 polarization upon PM2.5 exposure. Importantly, PP2A-B56α holoenzyme was shown to complex with mTOR/p70S6K/4E-BP1, and suppression of B56α led to enhanced phosphorylation of mTOR, p70S6K, and 4E-BP1. These observations demonstrate that the PP2A-mTOR-p70S6K/4E-BP1 signaling is a critical pathway in mediating macrophage M1 polarization, which contributes to PM-induced pulmonary injury.
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Affiliation(s)
- Shen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Liping Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Lizhu Ye
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Yue Jiang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Qiong Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Haiyan Zhang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Rui Zhang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Huiyao Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Dianke Yu
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China
| | - Rong Zhang
- Department of Toxicology, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China
| | - Yujie Niu
- Department of Toxicology, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China
| | - Qun Zhao
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Jianhui Liu
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Gangfeng Ouyang
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Yuxin Zheng
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China
| | - Lihua Zhang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Wen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Daochuan Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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Shao L, Ma Y, Fang Q, Huang Z, Wan S, Wang J, Yang L. Role of protein phosphatase 2A in kidney disease (Review). Exp Ther Med 2021; 22:1236. [PMID: 34539832 PMCID: PMC8438693 DOI: 10.3892/etm.2021.10671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
Kidney disease affects millions of people worldwide and is a financial burden on the healthcare system. Protein phosphatase 2A (PP2A), which is involved in renal development and the function of ion-transport proteins, aquaporin-2 and podocytes, is likely to serve an important role in renal processes. PP2A is associated with the pathogenesis of a variety of different kidney diseases including podocyte injury, inflammation, tumors and chronic kidney disease. The current review aimed to discuss the structure and function of PP2A subunits in the context of kidney diseases. How dysregulation of PP2A in the kidneys causes podocyte death and the inactivation of PP2A in renal carcinoma tissues is discussed. Inhibition of PP2A activity prevents epithelial-mesenchymal transition and attenuates renal fibrosis, creating a favorable inflammatory microenvironment and promoting the initiation and progression of tumor pathogenesis. The current review also indicates that PP2A serves an important role in protection against renal inflammation. Understanding the detailed mechanisms of PP2A provides information that can be utilized in the design and application of novel therapeutics for the treatment and prevention of renal diseases.
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Affiliation(s)
- Lishi Shao
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Yiqun Ma
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Qixiang Fang
- Department of Urology, The First Affiliated Hospital of the Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China
| | - Ziye Huang
- Department of Urology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Shanshan Wan
- Department of Radiology, Yunnan Kun-Gang Hospital, Anning, Yunnan 650300, P.R. China
| | - Jiaping Wang
- Department of Radiology, Kunming Medical University and The Second Affiliated Hospital, Kunming, Yunnan 650500, P.R. China
| | - Li Yang
- Department of Anatomy, Histology and Embryology, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
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8
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Hsieh HH, Chen YA, Chang YJ, Wang HH, Yu YH, Lin SW, Huang YJ, Lin S, Chang CJ. The functional characterization of phosphorylation of tristetraprolin at C-terminal NOT1-binding domain. JOURNAL OF INFLAMMATION-LONDON 2021; 18:22. [PMID: 34090459 PMCID: PMC8180021 DOI: 10.1186/s12950-021-00288-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 05/20/2021] [Indexed: 12/26/2022]
Abstract
Background Tristetraprolin (TTP) family proteins contain conserved tandem CCCH zinc-finger binding to AU-rich elements and C-terminal NOT1-binding domain. TTP is phosphorylated extensively in cells, and its mRNA destabilization activity is regulated by protein phosphorylation. Methods We generated an antibody against phospho-Serine316 located at the C-terminal NOT1-binding site and examined TTP phosphorylation in LPS-stimulated RAW264.7 cells. Knockout of TTP was created in RAW264.7 cells using CRISPR/Cas9 gene editing to explore TTP functions. Results We demonstrated that Ser316 was phosphorylated by p90 ribosomal S6 kinase 1 (RSK1) and p38-activated protein kinase (MK2) and dephosphorylated by Protein Phosphatase 2A (PP2A). A phosphorylation-mimic mutant of S316D resulted in dissociation with the CCR4-NOT deadenylase complex through weakening interaction with CNOT1. Furthermore, Ser316 and serines 52 and 178 were independently contributed to the CCR4-NOT complex recruitment in the immunoprecipitation assay using phosphor-mimic mutants. In RAW264.7 macrophages, TTP was induced, and Ser316 was phosphorylated through RSK1 and MK2 by LPS stimulation. Knockout of TTP resulted in TNFα mRNA increased due to mRNA stabilization. Overexpression of non-phosphorylated S316A TTP mutant can restore TTP activity and lead to TNFα mRNA decreased. GST pull-down and RNA pull-down analyses demonstrated that endogenous TTP with Ser316 phosphorylation decreased the interaction with CNOT1. Conclusions Our results suggest that the TTP-mediated mRNA stability is modulated by Ser316 phosphorylation via regulating the TTP interaction with the CCR4-NOT deadenylase complex. Supplementary Information The online version contains supplementary material available at 10.1186/s12950-021-00288-2.
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Affiliation(s)
- Hsin-Hui Hsieh
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1 Sec 4 Roosevelt Rd, Taipei, 106, Taiwan
| | - Yen-An Chen
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1 Sec 4 Roosevelt Rd, Taipei, 106, Taiwan
| | - Yao-Jen Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsin-Hui Wang
- Department of Pediatrics, Division of Pediatric Immunology and Nephrology, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Pediatrics, Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Institute of Emergency and Critical Care Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ya-Han Yu
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1 Sec 4 Roosevelt Rd, Taipei, 106, Taiwan
| | - Sheng-Wei Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yin-Jung Huang
- Department of Pediatrics, Division of Pediatric Immunology and Nephrology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Steven Lin
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1 Sec 4 Roosevelt Rd, Taipei, 106, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Ching-Jin Chang
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1 Sec 4 Roosevelt Rd, Taipei, 106, Taiwan. .,Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
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9
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Nader CP, Cidem A, Verrills NM, Ammit AJ. Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer. Respir Res 2019; 20:222. [PMID: 31623614 PMCID: PMC6798356 DOI: 10.1186/s12931-019-1192-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023] Open
Abstract
Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.
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Affiliation(s)
- Cassandra P Nader
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Aylin Cidem
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, 2308, Australia
- Priority Research Centre for Cancer Research, Innovation & Translation, Faculty of Health & Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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Zhong Y, Lee K, Deng Y, Ma Y, Chen Y, Li X, Wei C, Yang S, Wang T, Wong NJ, Muwonge AN, Azeloglu EU, Zhang W, Das B, He JC, Liu R. Arctigenin attenuates diabetic kidney disease through the activation of PP2A in podocytes. Nat Commun 2019; 10:4523. [PMID: 31586053 PMCID: PMC6778111 DOI: 10.1038/s41467-019-12433-w] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/10/2019] [Indexed: 12/20/2022] Open
Abstract
Arctigenin (ATG) is a major component of Fructus Arctii, a traditional herbal remedy that reduced proteinuria in diabetic patients. However, whether ATG specifically provides renoprotection in DKD is not known. Here we report that ATG administration is sufficient to attenuate proteinuria and podocyte injury in mouse models of diabetes. Transcriptomic analysis of diabetic mouse glomeruli showed that cell adhesion and inflammation are two key pathways affected by ATG treatment, and mass spectrometry analysis identified protein phosphatase 2 A (PP2A) as one of the top ATG-interacting proteins in renal cells. Enhanced PP2A activity by ATG reduces p65 NF-κB-mediated inflammatory response and high glucose-induced migration in cultured podocytes via interaction with Drebrin-1. Importantly, podocyte-specific Pp2a deletion in mice exacerbates DKD injury and abrogates the ATG-mediated renoprotection. Collectively, our results demonstrate a renoprotective mechanism of ATG via PP2A activation and establish PP2A as a potential target for DKD progression.
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Affiliation(s)
- Yifei Zhong
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Kyung Lee
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yueyi Deng
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yueming Ma
- Department of Pharmacology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Yiping Chen
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xueling Li
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chengguo Wei
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Shumin Yang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tianming Wang
- Department of Pharmacology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Nicholas J Wong
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alecia N Muwonge
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Evren U Azeloglu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Bhaskar Das
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Renal Section, James J Peters Veterans Affair Medical Center, Bronx, NY, USA.
| | - Ruijie Liu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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11
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Clark AR, Ohlmeyer M. Protein phosphatase 2A as a therapeutic target in inflammation and neurodegeneration. Pharmacol Ther 2019; 201:181-201. [PMID: 31158394 PMCID: PMC6700395 DOI: 10.1016/j.pharmthera.2019.05.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022]
Abstract
Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric enzyme that catalyzes the selective removal of phosphate groups from protein serine and threonine residues. Emerging evidence suggests that it functions as a tumor suppressor by constraining phosphorylation-dependent signalling pathways that regulate cellular transformation and metastasis. Therefore, PP2A-activating drugs (PADs) are being actively sought and investigated as potential novel anti-cancer treatments. Here we explore the concept that PP2A also constrains inflammatory responses through its inhibitory effects on various signalling pathways, suggesting that PADs may be effective in the treatment of inflammation-mediated pathologies.
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Affiliation(s)
- Andrew R Clark
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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12
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Metformin reduced NLRP3 inflammasome activity in Ox-LDL stimulated macrophages through adenosine monophosphate activated protein kinase and protein phosphatase 2A. Eur J Pharmacol 2019; 852:99-106. [DOI: 10.1016/j.ejphar.2019.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/27/2019] [Accepted: 03/06/2019] [Indexed: 11/20/2022]
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Prostaglandin E 2, but not cAMP nor β 2-agonists, induce tristetraprolin (TTP) in human airway smooth muscle cells. Inflamm Res 2019; 68:369-377. [PMID: 30852628 DOI: 10.1007/s00011-019-01224-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 01/05/2023] Open
Abstract
Tristetraprolin (TTP) is an anti-inflammatory molecule known to post-transcriptionally regulate cytokine production and is, therefore, an attractive drug target for chronic respiratory diseases driven by inflammation, such as asthma and chronic obstructive pulmonary disease. Our recent in vitro studies in primary human airway smooth (ASM) cells have confirmed the essential anti-inflammatory role played by TTP as a critical partner in a cytokine regulatory network. However, several unanswered questions remain. While prior in vitro studies have suggested that TTP is regulated in a cAMP-mediated manner, raising the possibility that this may be one of the ways in which β2-agonists achieve beneficial effects beyond bronchodilation, the impact of β2-agonists on ASM cells is unknown. Furthermore, the effect of prostaglandin E2 (PGE2) on TTP expression in ASM cells has not been reported. We address this herein and reveal, for the first time, that TTP is not regulated by cAMP-activating agents nor following treatment with long-acting β2-agonists. However, PGE2 does induce TTP mRNA expression and protein upregulation in ASM cells. Although the underlying mechanism of action remains undefined, we can confirm that PGE2-induced TTP upregulation is not mediated via cAMP, or EP2/EP4 receptor activation, and occurred in a manner independent of the p38 MAPK-mediated pathway. Taken together, these data confirm that β2-agonists do not upregulate TTP in human ASM cells and indicate that another way in which PGE2 may achieve beneficial effects in asthma and COPD may be via upregulation of the master controller of inflammation-TTP.
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Zhang J, Meng Y, Wu H, Wu Y, Yang B, Wang L. Association between PPP2CA polymorphisms and clinical features in southwest Chinese systemic lupus erythematosus patients. Medicine (Baltimore) 2018; 97:e11451. [PMID: 29979448 PMCID: PMC6076051 DOI: 10.1097/md.0000000000011451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Increasing evidence supports the involvement of a catalytic subunit (PP2Ac) of protein phosphatase 2A (PP2A) in the mechanisms of systemic lupus erythematosus (SLE). This study was conducted to explore the association single nucleotide polymorphisms (SNPs) of PPP2CA with SLE susceptibility, serum cytokines levels, and clinical features in a Chinese Han population. A case-control association study was carried out in 1509 Chinese Han subjects (730 SLE patients and 779 healthy individuals). Genotyping for genetic variants of PPP2CA (rs10491322 and rs7704116) was performed using a polymerase chain reaction-high resolution melting (PCR-HRM) assay. In the cohort of SLE patients, we observed that rs10491322 and rs7704116 were positively increased SLE susceptibility (OR = 1.61, 95% CI = 1.13-2.31, P = .009; OR = 1.59, 95% CI = 1.17-2.15, P = .003, respectively). Interestingly, the AG genotype of rs10491322 carriers presented higher IL-6 (P < .001) and IL-17 (P < .001) than those with AA genotype carriers. Specifically, carriage of the rs10491322 G* allele led to a higher prevalence of arthritis in SLE patients (P = .01). This study demonstrated an association of PPP2CA (rs10491322 and rs7704116) with SLE susceptibility in a Chinese Han population. Furthermore, the minor allele of PPP2CA rs10491322 as a risk factor was correlated with immunologic disorders for SLE.
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Bott A, Erdem N, Lerrer S, Hotz-Wagenblatt A, Breunig C, Abnaof K, Wörner A, Wilhelm H, Münstermann E, Ben-Baruch A, Wiemann S. miRNA-1246 induces pro-inflammatory responses in mesenchymal stem/stromal cells by regulating PKA and PP2A. Oncotarget 2018; 8:43897-43914. [PMID: 28159925 PMCID: PMC5546423 DOI: 10.18632/oncotarget.14915] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/26/2016] [Indexed: 12/20/2022] Open
Abstract
The tumor microenvironment (TME) has an impact on breast cancer progression by creating a pro-inflammatory milieu within the tumor. However, little is known about the roles of miRNAs in cells of the TME during this process. We identified six putative oncomiRs in a breast cancer dataset, all strongly correlating with poor overall patient survival. Out of the six candidates, miR-1246 was upregulated in aggressive breast cancer subtypes and expressed at highest levels in mesenchymal stem/stroma cells (MSCs). Functionally, miR-1246 led to a p65-dependent increase in transcription and release of pro-inflammatory mediators IL-6, CCL2 and CCL5 in MSCs, and increased NF-κB activity. The pro-inflammatory phenotype of miR-1246 in MSCs was independent of TNFα stimulations and mediated by direct targeting of the tumor-suppressors PRKAR1A and PPP2CB. In vitro recapitulation of the TME revealed increased Stat3 phosphorylation in breast epithelial (MCF10A) and cancer cells (SK-BR-3, MCF7, T47D) upon incubation with conditioned medium (CM) of MSCs overexpressing miR-1246. Additionally, this stimulation enhanced proliferation of MCF10A cells, increased migration of MDA-MB-231 cells and induced attraction of THP-1 monocytic cells. Our data shows that miR-1246 acts as both key-enhancer of pro-inflammatory responses in MSCs and putative oncomiR in breast cancer, suggesting its influence on cancer-related inflammation and breast cancer progression.
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Affiliation(s)
- Alexander Bott
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nese Erdem
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Shalom Lerrer
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
| | - Agnes Hotz-Wagenblatt
- Bioinformatics Group, Genomics & Proteomics Core Facility (GPCF), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christian Breunig
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Khalid Abnaof
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Angelika Wörner
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Heike Wilhelm
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ewald Münstermann
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Adit Ben-Baruch
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
| | - Stefan Wiemann
- Division of Molecular Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Yin J, Li R, Liu W, Chen Y, Zhang X, Li X, He X, Duan C. Neuroprotective Effect of Protein Phosphatase 2A/Tristetraprolin Following Subarachnoid Hemorrhage in Rats. Front Neurosci 2018; 12:96. [PMID: 29535596 PMCID: PMC5835096 DOI: 10.3389/fnins.2018.00096] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/06/2018] [Indexed: 11/25/2022] Open
Abstract
Early brain injury (EBI) following subarachnoid hemorrhage (SAH) can lead to inflammation and neuronal dysfunction. There is a need for effective strategies to mitigate these effects and improve the outcome of patients who experience SAH. The mRNA-destabilizing protein tristetraprolin (TTP) is an anti-inflammatory factor that induces the decay of cytokine transcripts and has been implicated in diseases such as glioma. However, the mechanism of action of TTP in EBI after SAH is unclear. The present study investigated the effects of TTP regulation via phosphorylation in a rat model of SAH by protein phosphatase (PP)2A, which is a pleiotropic enzyme complex with multiple substrate phospho-proteins. We hypothesized that inhibitory phosphorylation of TTP by PP2A would reduce neuroinflammation and apoptosis. To evaluate the function of each factor, the PP2A agonist FTY720, short interfering (si)RNAs targeting TTP and PP2A were administered to rats by intracerebroventricular injection 24 h before SAH. Rats were evaluated with SAH grade, neurological score, brain water content and by western blotting, and terminal deoxynucleotidyltransferase dUTP nick-end labeling. We found that endogenous PP2A and TTP levels were increased after SAH. FTY720 induced PP2A activation would lead to dephosphorylation and activation of TTP and decreased production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8. SiRNA-mediated TTP knockdown abolished anti-inflammatory effects of FTY720 treatment, indicating that PP2A was associated with TTP activation in vivo. Decreased TNF-α, IL-6, and IL-8 levels were associated with improvement of neurological function, reduction of brain edema, suppression of caspase-3, and up-regulation of B cell lymphoma-2. These results demonstrated that PP2A activation could enhance the anti-inflammatory and anti-apoptotic effects of TTP, by which it might shed light on the development of an effective therapeutic strategy against EBI following SAH.
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Affiliation(s)
- Jian Yin
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Departments of Neurosurgery, Hanghzou Red Cross Hospital, Hangzhou, China
| | - Ran Li
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Wenchao Liu
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yunchang Chen
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xin Zhang
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xifeng Li
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xuying He
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Chuanzhi Duan
- The National Key Clinic Specialty, The Neurosurgery Institute of Guangdong Province, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
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O'Neil JD, Ammit AJ, Clark AR. MAPK p38 regulates inflammatory gene expression via tristetraprolin: Doing good by stealth. Int J Biochem Cell Biol 2018; 94:6-9. [PMID: 29128684 PMCID: PMC6562201 DOI: 10.1016/j.biocel.2017.11.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/07/2017] [Indexed: 12/14/2022]
Abstract
Tristetraprolin (TTP) is an RNA-destabilizing protein that exerts profound anti-inflammatory effects by inhibiting the expression of tumour necrosis factor and many other inflammatory mediators. The mitogen-activated protein kinase (MAPK) p38 signaling pathway controls the strength and duration of inflammatory responses by regulating both the expression and function of TTP. The kinase MK2 (MAPK activated kinase 2) is activated by MAPK p38, and in turn phosphorylates TTP at two critical serine residues. One consequence of these phosphorylations is the protection of TTP from proteasome-mediated degradation. Another consequence is the loss of mRNA destabilizing activity. The control of TTP expression and function by the MAPK p38 pathway provides an elegant mechanism for coupling the on and off phases of inflammatory responses, and dictating the precise kinetics of expression of individual inflammatory mediators.
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Affiliation(s)
- J D O'Neil
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, United Kingdom
| | - A J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, New South Wales, Australia; School of Life Sciences, Faculty of Science, University of Technology, Sydney, New South Wales, Australia
| | - A R Clark
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2WB, United Kingdom.
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Nair PM, Starkey MR, Haw TJ, Liu G, Horvat JC, Morris JC, Verrills NM, Clark AR, Ammit AJ, Hansbro PM. Targeting PP2A and proteasome activity ameliorates features of allergic airway disease in mice. Allergy 2017; 72:1891-1903. [PMID: 28543283 DOI: 10.1111/all.13212] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2017] [Indexed: 12/22/2022]
Abstract
BACKGROUND Asthma is an allergic airway disease (AAD) caused by aberrant immune responses to allergens. Protein phosphatase-2A (PP2A) is an abundant serine/threonine phosphatase with anti-inflammatory activity. The ubiquitin proteasome system (UPS) controls many cellular processes, including the initiation of inflammatory responses by protein degradation. We assessed whether enhancing PP2A activity with fingolimod (FTY720) or 2-amino-4-(4-(heptyloxy) phenyl)-2-methylbutan-1-ol (AAL(S) ), or inhibiting proteasome activity with bortezomib (BORT), could suppress experimental AAD. METHODS Acute AAD was induced in C57BL/6 mice by intraperitoneal sensitization with ovalbumin (OVA) in combination with intranasal (i.n) exposure to OVA. Chronic AAD was induced in mice with prolonged i.n exposure to crude house dust mite (HDM) extract. Mice were treated with vehicle, FTY720, AAL(S) , BORT or AAL(S) +BORT and hallmark features of AAD assessed. RESULTS AAL(S) reduced the severity of acute AAD by suppressing tissue eosinophils and inflammation, mucus-secreting cell (MSC) numbers, type 2-associated cytokines (interleukin (IL)-33, thymic stromal lymphopoietin, IL-5 and IL-13), serum immunoglobulin (Ig)E and airway hyper-responsiveness (AHR). FTY720 only suppressed tissue inflammation and IgE. BORT reduced bronchoalveolar lavage fluid (BALF) and tissue eosinophils and inflammation, IL-5, IL-13 and AHR. Combined treatment with AAL(S) +BORT had complementary effects and suppressed BALF and tissue eosinophils and inflammation, MSC numbers, reduced the production of type 2 cytokines and AHR. AAL(S) , BORT and AAL(S) +BORT also reduced airway remodelling in chronic AAD. CONCLUSION These findings highlight the potential of combination therapies that enhance PP2A and inhibit proteasome activity as novel therapeutic strategies for asthma.
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Affiliation(s)
- P. M. Nair
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - M. R. Starkey
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - T. J. Haw
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - G. Liu
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - J. C. Horvat
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - J. C. Morris
- School of Chemistry; University of New South Wales; Sydney NSW Australia
| | - N. M. Verrills
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - A. R. Clark
- Institute of Inflammation and Ageing; College of Medical and Dental Sciences; University of Birmingham; Birmingham UK
| | - A. J. Ammit
- Woolcock Emphysema Centre; Woolcock Institute of Medical Research; University of Sydney; Sydney NSW Australia
- Faculty of Science; School of Life Sciences; University of Technology Sydney; Sydney NSW Australia
| | - P. M. Hansbro
- Priority Research Centres for Healthy Lungs; Grow up Well and Cancer Research, Innovation and Translation; University of Newcastle & Hunter Medical Research Institute; New Lambton Heights NSW Australia
- Faculty of Health and Medicine; School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
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The control of inflammation via the phosphorylation and dephosphorylation of tristetraprolin: a tale of two phosphatases. Biochem Soc Trans 2017; 44:1321-1337. [PMID: 27911715 PMCID: PMC5095909 DOI: 10.1042/bst20160166] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/14/2022]
Abstract
Twenty years ago, the first description of a tristetraprolin (TTP) knockout mouse highlighted the fundamental role of TTP in the restraint of inflammation. Since then, work from several groups has generated a detailed picture of the expression and function of TTP. It is a sequence-specific RNA-binding protein that orchestrates the deadenylation and degradation of several mRNAs encoding inflammatory mediators. It is very extensively post-translationally modified, with more than 30 phosphorylations that are supported by at least two independent lines of evidence. The phosphorylation of two particular residues, serines 52 and 178 of mouse TTP (serines 60 and 186 of the human orthologue), has profound effects on the expression, function and localisation of TTP. Here, we discuss the control of TTP biology via its phosphorylation and dephosphorylation, with a particular focus on recent advances and on questions that remain unanswered.
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20
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Patel BS, Rahman MM, Rumzhum NN, Oliver BG, Verrills NM, Ammit AJ. Theophylline Represses IL-8 Secretion from Airway Smooth Muscle Cells Independently of Phosphodiesterase Inhibition. Novel Role as a Protein Phosphatase 2A Activator. Am J Respir Cell Mol Biol 2017; 54:792-801. [PMID: 26574643 DOI: 10.1165/rcmb.2015-0308oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Theophylline is an old drug experiencing a renaissance owing to its beneficial antiinflammatory effects in chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease. Multiple modes of antiinflammatory action have been reported, including inhibition of the enzymes that degrade cAMP-phosphodiesterase (PDE). Using primary cultures of airway smooth muscle (ASM) cells, we recently revealed that PDE4 inhibitors can potentiate the antiinflammatory action of β2-agonists by augmenting cAMP-dependent expression of the phosphatase that deactivates mitogen-activated protein kinase (MAPK)-MAPK phosphatase (MKP)-1. Therefore, the aim of this study was to address whether theophylline repressed cytokine production in a similar, PDE-dependent, MKP-1-mediated manner. Notably, theophylline did not potentiate cAMP release from ASM cells treated with the long-acting β2-agonist formoterol. Moreover, theophylline (0.1-10 μM) did not increase formoterol-induced MKP-1 messenger RNA expression nor protein up-regulation, consistent with the lack of cAMP generation. However, theophylline (at 10 μM) was antiinflammatory and repressed secretion of the neutrophil chemoattractant cytokine IL-8, which is produced in response to TNF-α. Because theophylline's effects were independent of PDE4 inhibition or antiinflammatory MKP-1, we then wished to elucidate the novel mechanisms responsible. We investigated the impact of theophylline on protein phosphatase (PP) 2A, a master controller of multiple inflammatory signaling pathways, and show that theophylline increases TNF-α-induced PP2A activity in ASM cells. Confirmatory results were obtained in A549 lung epithelial cells. PP2A activators have beneficial effects in ex vivo and in vivo models of respiratory disease. Thus, our study is the first to link theophylline with PP2A activation as a novel mechanism to control respiratory inflammation.
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Affiliation(s)
| | | | - Nowshin N Rumzhum
- 1 Faculty of Pharmacy, University of Sydney, New South Wales, Australia
| | - Brian G Oliver
- 2 Woolcock Institute of Medical Research, University of Sydney, New South Wales, Australia.,3 School of Life Sciences, University of Technology, Sydney, New South Wales, Australia; and
| | - Nicole M Verrills
- 4 School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, New South Wales
| | - Alaina J Ammit
- 1 Faculty of Pharmacy, University of Sydney, New South Wales, Australia
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Newton R, Shah S, Altonsy MO, Gerber AN. Glucocorticoid and cytokine crosstalk: Feedback, feedforward, and co-regulatory interactions determine repression or resistance. J Biol Chem 2017; 292:7163-7172. [PMID: 28283576 DOI: 10.1074/jbc.r117.777318] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Inflammatory signals induce feedback and feedforward systems that provide temporal control. Although glucocorticoids can repress inflammatory gene expression, glucocorticoid receptor recruitment increases expression of negative feedback and feedforward regulators, including the phosphatase, DUSP1, the ubiquitin-modifying enzyme, TNFAIP3, or the mRNA-destabilizing protein, ZFP36. Moreover, glucocorticoid receptor cooperativity with factors, including nuclear factor-κB (NF-κB), may enhance regulator expression to promote repression. Conversely, MAPKs, which are inhibited by glucocorticoids, provide feedforward control to limit expression of the transcription factor IRF1, and the chemokine, CXCL10. We propose that modulation of feedback and feedforward control can determine repression or resistance of inflammatory gene expression toglucocorticoid.
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Affiliation(s)
- Robert Newton
- From the Airways Inflammation Research Group, Snyder Institute for Chronic Diseases, University of Calgary, Alberta T2N 4Z6, Canada,
| | - Suharsh Shah
- the Arnie Charbonneau Cancer Institute, Department of Oncology, University of Calgary, Alberta T2N 4Z6, Canada
| | - Mohammed O Altonsy
- From the Airways Inflammation Research Group, Snyder Institute for Chronic Diseases, University of Calgary, Alberta T2N 4Z6, Canada.,the Faculty of Science, Sohag University, Sohag 82524, Egypt, and
| | - Antony N Gerber
- the Department of Medicine, National Jewish Health, Denver, Colorado 80206
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22
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Klemm C, Bruchhagen C, van Krüchten A, Niemann S, Löffler B, Peters G, Ludwig S, Ehrhardt C. Mitogen-activated protein kinases (MAPKs) regulate IL-6 over-production during concomitant influenza virus and Staphylococcus aureus infection. Sci Rep 2017; 7:42473. [PMID: 28195157 PMCID: PMC5307969 DOI: 10.1038/srep42473] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 01/11/2017] [Indexed: 12/20/2022] Open
Abstract
Bacterial super-infections are a major complication of influenza virus (IV) infections and often lead to severe pneumonia. One hallmark of IV-associated Staphylococcus aureus (S. aureus) infection is rapid progression to a serious disease outcome. Changes in immune and inflammatory host responses increase morbidity and complicate efficient therapy. A key player during inflammation is the multifunctional cytokine IL-6. Although increased IL-6 levels have been observed after severe disease upon IV and/or bacterial super-infection, the underlying molecular mechanisms still remain to be elucidated. In the present study, we focused on cellular signalling pathways regulating IL-6 production upon IV/S. aureus super-infection. Additionally, infection with viable bacteria was mimicked by lipoteichoic acid stimulation in this model. Analyses of cellular signalling mechanisms revealed synergistically increased activation of the MAPK p38 as well as enhanced phosphorylation of the MAPKs ERK1/2 and JNK in the presence of super-infecting bacteria. Interestingly, inhibition of MAPK activity indicated a strong dependence of IL-6 expression on p38 and ERK1/2, while the MAPK JNK seems not to be involved. Thus, our results provide new molecular insights into the regulation of IL-6, a marker of severe disease, which might contribute to the lethal synergism of IV and S. aureus.
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Affiliation(s)
- Carolin Klemm
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Christin Bruchhagen
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Andre van Krüchten
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Silke Niemann
- Institute of Medical Microbiology, University Hospital of Muenster, Domagkstr, 10, D-48149 Muenster, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, University Hospital Jena, Erlanger Allee 101, D-07747 Jena, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital of Muenster, Domagkstr, 10, D-48149 Muenster, Germany.,Cluster of Excellence Cells in Motion (CIM), University of Muenster, Muenster, Germany
| | - Stephan Ludwig
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von Esmarch-Str. 56, D-48149 Muenster, Germany.,Cluster of Excellence Cells in Motion (CIM), University of Muenster, Muenster, Germany
| | - Christina Ehrhardt
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, Von Esmarch-Str. 56, D-48149 Muenster, Germany.,Cluster of Excellence Cells in Motion (CIM), University of Muenster, Muenster, Germany
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Rahman MM, Prünte L, Lebender LF, Patel BS, Gelissen I, Hansbro PM, Morris JC, Clark AR, Verrills NM, Ammit AJ. The phosphorylated form of FTY720 activates PP2A, represses inflammation and is devoid of S1P agonism in A549 lung epithelial cells. Sci Rep 2016; 6:37297. [PMID: 27849062 PMCID: PMC5110966 DOI: 10.1038/srep37297] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 10/27/2016] [Indexed: 12/21/2022] Open
Abstract
Protein phosphatase 2A (PP2A) activity can be enhanced pharmacologically by PP2A-activating drugs (PADs). The sphingosine analog FTY720 is the best known PAD and we have shown that FTY720 represses production of pro-inflammatory cytokines responsible for respiratory disease pathogenesis. Whether its phosphorylated form, FTY720-P, also enhances PP2A activity independently of the sphingosine 1-phosphate (S1P) pathway was unknown. Herein, we show that FTY720-P enhances TNF-induced PP2A phosphatase activity and significantly represses TNF-induced interleukin 6 (IL-6) and IL-8 mRNA expression and protein secretion from A549 lung epithelial cells. Comparing FTY720 and FTY720-P with S1P, we show that unlike S1P, the sphingosine analogs do not induce cytokine production on their own. In fact, FTY720 and FTY720-P significantly repress S1P-induced IL-6 and IL-8 production. We then examined their impact on expression of cyclooxygenase 2 (COX-2) and resultant prostaglandin E2 (PGE2) production. S1P did not increase production of this pro-inflammatory enzyme because COX-2 mRNA gene expression is NF-κB-dependent, and unlike TNF, S1P did not activate NF-κB. However, TNF-induced COX-2 mRNA expression and PGE2 secretion is repressed by FTY720 and FTY720-P. Hence, FTY720-P enhances PP2A activity and that PADs can repress production of pro-inflammatory cytokines and enzymes in A549 lung epithelial cells in a manner devoid of S1P agonism.
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Affiliation(s)
| | - Laura Prünte
- Faculty of Pharmacy, University of Sydney, NSW, 2006, Australia
| | | | | | - Ingrid Gelissen
- Faculty of Pharmacy, University of Sydney, NSW, 2006, Australia
| | - Philip M. Hansbro
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute and the University of Newcastle, NSW, 2308, Australia
| | | | - Andrew R. Clark
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Nicole M. Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, NSW, 2308, Australia
| | - Alaina J. Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, NSW, Australia
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW, Australia
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24
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Terna E, Luukkainen A, Seppälä M, Renkonen R, Huhtala H, Tommola S, Paavonen T, Kauppi P, Tynninen O, Jeskanen L, Toppila-Salmi S. The expression of cancerous inhibitor protein phosphatase 2A in chronic rhinosinusitis with nasal polyps. Acta Otolaryngol 2016; 136:1173-1179. [PMID: 27348236 DOI: 10.1080/00016489.2016.1195918] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
CONCLUSION The study suggests that cancerous inhibitor of protein phosphatase 2A (CIP2A) expression and eosinophilia associate with chronic rhinosinusitis with nasal polyps with aspirin exacerbated respiratory disease (CRSwNP + AERD). Further studies with a larger sample size are needed to evaluate further the role of CIP2A and related pathways in CRSwNP + AERD. OBJECTIVES Low prostaglandin E2 levels putatively associate with CRSwNP + AERD and decreased c-Myc levels. The aim of this study was to evaluate the expression and revision-predictive role of oncoprotein CIP2A, another c-Myc modulator, in CRSwNP with/without AERD, and in antrochoanal polyps. METHOD Ninety retrospective archival objective glasses of nasal polyp tissue from CRSwNP or ACP patients were used for assessing mucosal eosinophilia. Of this population, 90 archival nasal polyp specimens were available for immunohistochemical staining with a polyclonal anti-CIP2A antibody, together with 19 control nasal mucosa specimens. CIP2A staining intensity and tissue eosinophilia were assessed by two blinded observers with a light microscope. Subject characteristics from 90 patients and 19 controls were obtained from patient records and additionally by a questionnaire from controls. The follow-up data was available from patient records of 84 patients and 16 controls. RESULTS The expression of epithelial CIP2A was detected both in control inferior turbinate mucosa and nasal polyps. The expression was significantly lower in the CRSwNP + AERD group compared to controls and CRSwNP without AERD (p < 0.01). High mucosal eosinophilia associated with CRSwNP (p < 0.01). Neither CIP2A nor eosinophilia predicted the need for revision surgery (p > 0.05), whereas previous surgery, allergic rhinitis, and use of corticosteroids did predict the need for revision surgery (p < 0.05).
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25
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Rahman MM, Prabhala P, Rumzhum NN, Patel BS, Wickop T, Hansbro PM, Verrills NM, Ammit AJ. TLR2 ligation induces corticosteroid insensitivity in A549 lung epithelial cells: Anti-inflammatory impact of PP2A activators. Int J Biochem Cell Biol 2016; 78:279-287. [PMID: 27477309 DOI: 10.1016/j.biocel.2016.07.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 07/21/2016] [Accepted: 07/27/2016] [Indexed: 01/18/2023]
Abstract
Corticosteroids are effective anti-inflammatory therapies widely utilized in chronic respiratory diseases. But these medicines can lose their efficacy during respiratory infection resulting in disease exacerbation. Further in vitro research is required to understand how infection worsens lung function control in order to advance therapeutic options to treat infectious exacerbation in the future. In this study, we utilize a cellular model of bacterial exacerbation where we pretreat A549 lung epithelial cells with the synthetic bacterial lipoprotein Pam3CSK4 (a TLR2 ligand) to mimic bacterial infection and tumor necrosis factor α (TNFα) to simulate inflammation. Under these conditions, Pam3CSK4 induces corticosteroid insensitivity; demonstrated by substantially reduced ability of the corticosteroid dexamethasone to repress TNFα-induced interleukin 6 secretion. We then explored the molecular mechanism responsible and found that corticosteroid insensitivity induced by bacterial mimics was not due to altered translocation of the glucocorticoid receptor into the nucleus, nor an impact on the NF-κB pathway. Moreover, Pam3CSK4 did not affect corticosteroid-induced upregulation of anti-inflammatory MAPK deactivating phosphatase-MKP-1. However, Pam3CSK4 can induce oxidative stress and we show that a proportion of the MKP-1 produced in response to corticosteroid in the context of TLR2 ligation was rendered inactive by oxidation. Thus to combat inflammation in the context of bacterial exacerbation we sought to discover effective strategies that bypassed this road-block. We show for the first time that known (FTY720) and novel (theophylline) activators of the phosphatase PP2A can serve as non-steroidal anti-inflammatory alternatives and/or corticosteroid-sparing approaches in respiratory inflammation where corticosteroid insensitivity exists.
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Affiliation(s)
| | - Pavan Prabhala
- Faculty of Pharmacy, University of Sydney, NSW, Australia
| | | | | | - Thomas Wickop
- Faculty of Pharmacy, University of Sydney, NSW, Australia
| | - Philip M Hansbro
- Priority Research Centre for Respiratory Diseases, Hunter Medical Research Institute and The University of Newcastle, Newcastle, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, NSW, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, NSW, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW, Australia.
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26
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Prabhala P, Bunge K, Ge Q, Ammit AJ. Corticosteroid-Induced MKP-1 Represses Pro-Inflammatory Cytokine Secretion by Enhancing Activity of Tristetraprolin (TTP) in ASM Cells. J Cell Physiol 2016; 231:2153-8. [PMID: 26825339 DOI: 10.1002/jcp.25327] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/29/2016] [Indexed: 11/06/2022]
Abstract
Exaggerated cytokine secretion drives pathogenesis of a number of chronic inflammatory diseases, including asthma. Anti-inflammatory pharmacotherapies, including corticosteroids, are front-line therapies and although they have proven clinical utility, the molecular mechanisms responsible for their actions are not fully understood. The corticosteroid-inducible gene, mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1, DUSP1) has emerged as a key molecule responsible for the repressive effects of steroids. MKP-1 is known to deactivate p38 MAPK phosphorylation and can control the expression and activity of the mRNA destabilizing protein-tristetraprolin (TTP). But whether corticosteroid-induced MKP-1 acts via p38 MAPK-mediated modulation of TTP function in a pivotal airway cell type, airway smooth muscle (ASM), was unknown. While pretreatment of ASM cells with the corticosteroid dexamethasone (preventative protocol) is known to reduce ASM synthetic function in vitro, the impact of adding dexamethasone after stimulation (therapeutic protocol) had not been explored. Whether dexamethasone modulates TTP in a p38 MAPK-dependent manner in this cell type was also unknown. We address this herein and utilize an in vitro model of asthmatic inflammation where ASM cells were stimulated with the pro-asthmatic cytokine tumor necrosis factor (TNF) and the impact of adding dexamethasone 1 h after stimulation assessed. IL-6 mRNA expression and protein secretion was significantly repressed by dexamethasone acting in a temporally distinct manner to increase MKP-1, deactivate p38 MAPK, and modulate TTP phosphorylation status. In this way, dexamethasone-induced MKP-1 acts via p38 MAPK to switch on the mRNA destabilizing function of TTP to repress pro-inflammatory cytokine secretion from ASM cells. J. Cell. Physiol. 231: 2153-2158, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Pavan Prabhala
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
| | - Kristin Bunge
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
| | - Qi Ge
- Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Alaina J Ammit
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
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27
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Rahman MM, Rumzhum NN, Hansbro PM, Morris JC, Clark AR, Verrills NM, Ammit AJ. Activating protein phosphatase 2A (PP2A) enhances tristetraprolin (TTP) anti-inflammatory function in A549 lung epithelial cells. Cell Signal 2016; 28:325-34. [PMID: 26820662 DOI: 10.1016/j.cellsig.2016.01.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/21/2016] [Accepted: 01/23/2016] [Indexed: 12/13/2022]
Abstract
Chronic respiratory diseases are driven by inflammation, but some clinical conditions (severe asthma, COPD) are refractory to conventional anti-inflammatory therapies. Thus, novel anti-inflammatory strategies are necessary. The mRNA destabilizing protein, tristetraprolin (TTP), is an anti-inflammatory molecule that functions to induce mRNA decay of cytokines that drive pathogenesis of respiratory disorders. TTP is regulated by phosphorylation and protein phosphatase 2A (PP2A) is responsible for dephosphorylating (and hence activating) TTP, amongst other targets. PP2A is activated by small molecules, FTY720 and AAL(S), and in this study we examine whether these compounds repress cytokine production in a cellular model of airway inflammation using A549 lung epithelial cells stimulated with tumor necrosis factor α (TNFα) in vitro. PP2A activators significantly increase TNFα-induced PP2A activity and inhibit mRNA expression and protein secretion of interleukin 8 (IL-8) and IL-6; two key pro-inflammatory cytokines implicated in respiratory disease and TTP targets. The effect of PP2A activators is not via an increase in TNFα-induced TTP mRNA expression; instead we demonstrate a link between PP2A activation and TTP anti-inflammatory function by showing that specific knockdown of TTP with siRNA reversed the repression of TNFα-induced IL-8 and IL-6 mRNA expression and protein secretion by FTY720. Therefore we propose that PP2A activators affect the dynamic equilibrium regulating TTP; shifting the equilibrium from phosphorylated (inactive) towards unphosphorylated (active) but unstable TTP. PP2A activators boost the anti-inflammatory function of TTP and have implications for future pharmacotherapeutic strategies to combat inflammation in respiratory disease.
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Affiliation(s)
| | | | - Philip M Hansbro
- Priority Research Centre for Respiratory Diseases, Hunter Medical Research Institute, University of Newcastle, NSW 2308, Australia
| | | | - Andrew R Clark
- Centre for Translational Inflammation Research, School of Immunity and Infection, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, NSW 2308, Australia
| | - Alaina J Ammit
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
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