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Bataclan M, Leoni C, Moro SG, Pecoraro M, Wong EH, Heissmeyer V, Monticelli S. Crosstalk between Regnase-1 and -3 shapes mast cell survival and cytokine expression. Life Sci Alliance 2024; 7:e202402784. [PMID: 38830770 PMCID: PMC11147952 DOI: 10.26508/lsa.202402784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
Post-transcriptional regulation of immune-related transcripts by RNA-binding proteins (RBPs) impacts immune cell responses, including mast cell functionality. Despite their importance in immune regulation, the functional role of most RBPs remains to be understood. By manipulating the expression of specific RBPs in murine mast cells, coupled with mass spectrometry and transcriptomic analyses, we found that the Regnase family of proteins acts as a potent regulator of mast cell physiology. Specifically, Regnase-1 is required to maintain basic cell proliferation and survival, whereas both Regnase-1 and -3 cooperatively regulate the expression of inflammatory transcripts upon activation, with Tnf being a primary target in both human and mouse cells. Furthermore, Regnase-3 directly interacts with Regnase-1 in mast cells and is necessary to restrain Regnase-1 expression through the destabilization of its transcript. Overall, our study identifies protein interactors of endogenously expressed Regnase factors, characterizes the regulatory interplay between Regnase family members in mast cells, and establishes their role in the control of mast cell homeostasis and inflammatory responses.
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Affiliation(s)
- Marian Bataclan
- https://ror.org/05gfswd81 Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Cristina Leoni
- https://ror.org/05gfswd81 Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Simone G Moro
- https://ror.org/05gfswd81 Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Matteo Pecoraro
- https://ror.org/05gfswd81 Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Elaine H Wong
- Institute for Immunology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Planegg-Martinsried, Germany
| | - Vigo Heissmeyer
- Institute for Immunology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Planegg-Martinsried, Germany
- Research Unit Molecular Immune Regulation, Helmholtz Zentrum München, Munich, Germany
| | - Silvia Monticelli
- https://ror.org/05gfswd81 Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
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2
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Scinicariello S, Soderholm A, Schäfer M, Shulkina A, Schwartz I, Hacker K, Gogova R, Kalis R, Froussios K, Budroni V, Bestehorn A, Clausen T, Kovarik P, Zuber J, Versteeg GA. HUWE1 controls tristetraprolin proteasomal degradation by regulating its phosphorylation. eLife 2023; 12:e83159. [PMID: 36961408 PMCID: PMC10038661 DOI: 10.7554/elife.83159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/26/2023] [Indexed: 03/25/2023] Open
Abstract
Tristetraprolin (TTP) is a critical negative immune regulator. It binds AU-rich elements in the untranslated-regions of many mRNAs encoding pro-inflammatory mediators, thereby accelerating their decay. A key but poorly understood mechanism of TTP regulation is its timely proteolytic removal: TTP is degraded by the proteasome through yet unidentified phosphorylation-controlled drivers. In this study, we set out to identify factors controlling TTP stability. Cellular assays showed that TTP is strongly lysine-ubiquitinated, which is required for its turnover. A genetic screen identified the ubiquitin E3 ligase HUWE1 as a strong regulator of TTP proteasomal degradation, which we found to control TTP stability indirectly by regulating its phosphorylation. Pharmacological assessment of multiple kinases revealed that HUWE1-regulated TTP phosphorylation and stability was independent of the previously characterized effects of MAPK-mediated S52/S178 phosphorylation. HUWE1 function was dependent on phosphatase and E3 ligase binding sites identified in the TTP C-terminus. Our findings indicate that while phosphorylation of S52/S178 is critical for TTP stabilization at earlier times after pro-inflammatory stimulation, phosphorylation of the TTP C-terminus controls its stability at later stages.
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Affiliation(s)
- Sara Scinicariello
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Adrian Soderholm
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Markus Schäfer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Alexandra Shulkina
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Irene Schwartz
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Kathrin Hacker
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Rebeca Gogova
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Robert Kalis
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Kimon Froussios
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
| | - Valentina Budroni
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Annika Bestehorn
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Tim Clausen
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Pavel Kovarik
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC)ViennaAustria
- Medical University of Vienna, Vienna BioCenter (VBC)ViennaAustria
| | - Gijs A Versteeg
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC)ViennaAustria
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3
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Shen Q, Zhao L, Pan L, Li D, Chen G, Chen Z, Jiang Z. Soluble SIRP-Alpha Promotes Murine Acute Lung Injury Through Suppressing Macrophage Phagocytosis. Front Immunol 2022; 13:865579. [PMID: 35634325 PMCID: PMC9133620 DOI: 10.3389/fimmu.2022.865579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 04/13/2022] [Indexed: 11/17/2022] Open
Abstract
Soluble signal regulatory protein-alpha (SIRP-alpha) is elevated in bronchoalveolar lavage (BAL) of mice with lipopolysaccharides (LPS)-induced acute lung injury (ALI). To define the role of soluble SIRP-alpha in the pathogenesis of ALI, we established murine ALI in wild-type (WT) and SIRP-alpha knock-out (KO) mice by intratracheal administration of LPS. The results indicated that lack of SIRP-alpha significantly reduced the pathogenesis of ALI, in association with attenuated lung inflammation, infiltration of neutrophils and expression of pro-inflammatory cytokines in mice. In addition, lack of SIRP-alpha reduced the expression of pro-inflammatory cytokines in LPS-treated bone marrow-derived macrophages (BMDMs) from KO mice, accompanied with improved macrophage phagocytosis. Blockade of soluble SIRP-alpha activity in ALI BAL by anti-SIRP-alpha antibody (aSIRP) effectively reduced the expression of TNF-alpha and IL-6 mRNA transcripts and proteins, improved macrophage phagocytosis in vitro. In addition, lack of SIRP-alpha reduced activation of Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1) and improved activation of signal transducer and activator of transcription-3 (STAT3) and STAT6. Suppression of SHP-1 activity by tyrosine phosphatase inhibitor 1 (TPI-1) increased activation of STAT3 and STAT6, and improved macrophage phagocytosis, that was effectively reversed by STAT3 and STAT6 inhibitors. Thereby, SIRP-alpha suppressed macrophage phagocytosis through activation of SHP-1, subsequently inhibiting downstream STAT3 and STAT6 signaling. Lack of SIRP-alpha attenuated murine ALI possibly through increasing phagocytosis, and improving STAT3 and STAT6 signaling in macrophages. SIRP-alpha would be promising biomarker and molecular target in the treatment of murine ALI and patients with acute respiratory distress syndrome (ARDS).
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Affiliation(s)
- Qinjun Shen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Li Zhao
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Linyue Pan
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Dandan Li
- Department of Pulmonary and Critical Care Medicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Gang Chen
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhihong Chen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhilong Jiang
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
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4
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Bataclan M, Leoni C, Monticelli S. RNA-binding proteins and RNA methylation in myeloid cells. Immunol Rev 2021; 304:51-61. [PMID: 34523134 PMCID: PMC7615035 DOI: 10.1111/imr.13025] [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: 06/11/2021] [Revised: 08/26/2021] [Accepted: 09/02/2021] [Indexed: 11/30/2022]
Abstract
RNA-binding proteins (RBPs) regulate all aspects of the life of mRNA transcripts. They are critically important in regulating immune responses, most notably by restraining excessive inflammation that can potentially lead to tissue damage. RBPs are also crucial for pathogen sensing, for instance for the recognition of viral nucleic acids. Concordant with these central regulatory roles, the dysregulated activity of many RBPs can give rise to disease. The expression and function of RBPs are therefore highly controlled by an elaborate network of transcriptional, post-transcriptional and post-translational mechanisms, including the ability of different RBPs to cross-regulate each other's expression. With an emphasis on macrophages and mast cells, we review current knowledge on the role of selected RBPs that have been shown to directly impact the expression of inflammatory transcripts. By focusing specifically on proteins of the Regnase and ZFP36 family, as well as on factors involved in N6 -methyladenosine (m6 A) deposition and recognition, we discuss mechanism of action, regulatory feedback, and impact of these selected proteins on immune responses. Finally, we include examples of the role of m6 A and RBPs in the recognition of viral RNAs. Overall, we provide a general overview of the impact of selected RBPs on the myeloid compartment, followed by a discussion of outstanding questions and challenges for the future.
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Affiliation(s)
- Marian Bataclan
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vincenzo Vela 6, CH-6500 Bellinzona, Switzerland
| | - Cristina Leoni
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vincenzo Vela 6, CH-6500 Bellinzona, Switzerland
| | - Silvia Monticelli
- Institute for Research in Biomedicine, Università della Svizzera italiana, Via Vincenzo Vela 6, CH-6500 Bellinzona, Switzerland
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5
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Kovarik P, Bestehorn A, Fesselet J. Conceptual Advances in Control of Inflammation by the RNA-Binding Protein Tristetraprolin. Front Immunol 2021; 12:751313. [PMID: 34603339 PMCID: PMC8484758 DOI: 10.3389/fimmu.2021.751313] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
Regulated changes in mRNA stability are critical drivers of gene expression adaptations to immunological cues. mRNA stability is controlled mainly by RNA-binding proteins (RBPs) which can directly cleave mRNA but more often act as adaptors for the recruitment of the RNA-degradation machinery. One of the most prominent RBPs with regulatory roles in the immune system is tristetraprolin (TTP). TTP targets mainly inflammation-associated mRNAs for degradation and is indispensable for the resolution of inflammation as well as the maintenance of immune homeostasis. Recent advances in the transcriptome-wide knowledge of mRNA expression and decay rates together with TTP binding sites in the target mRNAs revealed important limitations in our understanding of molecular mechanisms of TTP action. Such orthogonal analyses lead to the discovery that TTP binding destabilizes some bound mRNAs but not others in the same cell. Moreover, comparisons of various immune cells indicated that an mRNA can be destabilized by TTP in one cell type while it remains stable in a different cell linage despite the presence of TTP. The action of TTP extends from mRNA destabilization to inhibition of translation in a subset of targets. This article will discuss these unexpected context-dependent functions and their implications for the regulation of immune responses. Attention will be also payed to new insights into the role of TTP in physiology and tissue homeostasis.
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Affiliation(s)
- Pavel Kovarik
- Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
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6
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Bhuiyan P, Chen Y, Karim M, Dong H, Qian Y. Bidirectional communication between mast cells and the gut-brain axis in neurodegenerative diseases: Avenues for therapeutic intervention. Brain Res Bull 2021; 172:61-78. [PMID: 33892083 DOI: 10.1016/j.brainresbull.2021.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 03/02/2021] [Accepted: 04/17/2021] [Indexed: 12/12/2022]
Abstract
Although the global incidence of neurodegenerative diseases has been steadily increasing, especially in adults, there are no effective therapeutic interventions. Neurodegeneration is a heterogeneous group of disorders that is characterized by the activation of immune cells in the central nervous system (CNS) (e.g., mast cells and microglia) and subsequent neuroinflammation. Mast cells are found in the brain and the gastrointestinal tract and play a role in "tuning" neuroimmune responses. The complex bidirectional communication between mast cells and gut microbiota coordinates various dynamic neuro-cellular responses, which propagates neuronal impulses from the gastrointestinal tract into the CNS. Numerous inflammatory mediators from degranulated mast cells alter intestinal gut permeability and disrupt blood-brain barrier, which results in the promotion of neuroinflammatory processes leading to neurological disorders, thereby offsetting the balance in immune-surveillance. Emerging evidence supports the hypothesis that gut-microbiota exert a pivotal role in inflammatory signaling through the activation of immune and inflammatory cells. Communication between inflammatory cytokines and neurocircuits via the gut-brain axis (GBA) affects behavioral responses, activates mast cells and microglia that causes neuroinflammation, which is associated with neurological diseases. In this comprehensive review, we focus on what is currently known about mast cells and the gut-brain axis relationship, and how this relationship is connected to neurodegenerative diseases. We hope that further elucidating the bidirectional communication between mast cells and the GBA will not only stimulate future research on neurodegenerative diseases but will also identify new opportunities for therapeutic interventions.
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Affiliation(s)
- Piplu Bhuiyan
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China
| | - Yinan Chen
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China
| | - Mazharul Karim
- College of Pharmacy, Western University of Health Science, 309 East 2nd Street, Pomona, CA, 91766, USA
| | - Hongquan Dong
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China.
| | - Yanning Qian
- Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, PR China.
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7
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Ahras-Sifi N, Laraba-Djebari F. Immunomodulatory and protective effects of interleukin-4 on the neuropathological alterations induced by a potassium channel blocker. J Neuroimmunol 2021; 355:577549. [PMID: 33839521 DOI: 10.1016/j.jneuroim.2021.577549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/14/2021] [Accepted: 03/14/2021] [Indexed: 11/24/2022]
Abstract
The pathophysiology of neurological diseases related to potassium-channel dysfunction such as epilepsy is increasingly linked to immune system modulation. However, there are limited reports of which interleukin-4 (IL-4) can act on the neuroinflammatory response after seizure. Hence, we evaluated the effect of IL-4 in murine model of neuroexcitotoxcity using kaliotoxin (KTx), a potassium-channel blocker. Results showed that IL-4 treatment can significantly reduce the neuronal death induced by KTx. Probably by decreasing mitochondria swelling, reversing oxidative damage and enhancing Bcl-2 expression. Furthermore, IL-4 treatment significantly reduced TNF-α expression and enhanced GFAP and IL-10 expressions in the brain. IL-4 can be neuroprotective in epileptogenesis.
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Affiliation(s)
- Nesrine Ahras-Sifi
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria
| | - Fatima Laraba-Djebari
- USTHB, Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria.
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8
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Zhang Q, Wu G, Guo S, Liu Y, Liu Z. Effects of tristetraprolin on doxorubicin (adriamycin)-induced experimental kidney injury through inhibiting IL-13/STAT6 signal pathway. Am J Transl Res 2020; 12:1203-1221. [PMID: 32355536 PMCID: PMC7191163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
To study the effects of Tristetraprolin (TTP) on Doxorubicin (DOX)-induced experimental kidney injury (KI). DOX was used to induce kidney injury in Balb/c male mice (in vivo) and in human kidney proximal tubular epithelial cell line (HK-2) and normal rat kidney epithelial cell line (NRK-52E) (in vitro). Body weight of experimental mice were recorded daily. Histological changes were observed using hematoxylin-eosin (HE) staining, and levels of blood urea nitrogen, serum creatinine and serum cystatin C in KI mice, and MDA, LDH and SOD in cells were detected using the corresponding kits. Meanwhile, the 2, 7-dichlorodihydrofluorescein diacetate (DCF-DA) fluorescent staining was used to assess intracellular levels of reactive oxygen species (ROS). TTP and Kim-1 expressions were measured by immunohistochemistry and western blot. The TNF-α, IL-1β and IL-6 levels were evaluated by ELISA. Expressions of IL-13, STAT6, p-STAT6, Bcl-2, Bax, cleaved-caspase3 were detected using western blot, respectively. Cell Counting Kit-8 (CCK-8) was conducted for analyzing cell viability, and cells apoptosis were assessed by DAPI staining and flow cytometry. DOX treatment decreased body weight and aggravated renal injury without changes in water and food intake. DOX significantly reduced TTP expression, stimulated IL-13/STAT6 pathway and elevated the levels of several factors related to renal injury, including inflammatory response, oxidative stress and cell apoptosis, which were significantly restored by the treatment of overexpression TTP in vitro. Overexpression of TTP significantly reduces DOX-induced adverse outcomes so as to prevent renal injury. Inhibition of IL-13/STAT6 pathway may be the functional mechanism under TTP in experimental KI.
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Affiliation(s)
- Qian Zhang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, P. R. China
| | - Ge Wu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, P. R. China
| | - Shiyuan Guo
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, P. R. China
| | - Yong Liu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, P. R. China
| | - Zhangsuo Liu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, P. R. China
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9
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Roles of Tristetraprolin in Tumorigenesis. Int J Mol Sci 2018; 19:ijms19113384. [PMID: 30380668 PMCID: PMC6274954 DOI: 10.3390/ijms19113384] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/13/2022] Open
Abstract
Genetic loss or mutations in tumor suppressor genes promote tumorigenesis. The prospective tumor suppressor tristetraprolin (TTP) has been shown to negatively regulate tumorigenesis through destabilizing the messenger RNAs of critical genes implicated in both tumor onset and tumor progression. Regulation of TTP has therefore emerged as an important issue in tumorigenesis. Similar to other tumor suppressors, TTP expression is frequently downregualted in various human cancers, and its low expression is correlated with poor prognosis. Additionally, disruption in the regulation of TTP by various mechanisms results in the inactivation of TTP protein or altered TTP expression. A recent study showing alleviation of Myc-driven lymphomagenesis by the forced expression of TTP has shed light on new therapeutic avenues for cancer prevention and treatment through the restoration of TTP expression. In this review, we summarize key oncogenes subjected to the TTP-mediated mRNA degradation, and discuss how dysregulation of TTP can contribute to tumorigenesis. In addition, the control mechanism underlying TTP expression at the posttranscriptional and posttranslational levels will be discussed.
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10
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McCarthy PC, Phair IR, Greger C, Pardali K, McGuire VA, Clark AR, Gaestel M, Arthur JSC. IL-33 regulates cytokine production and neutrophil recruitment via the p38 MAPK-activated kinases MK2/3. Immunol Cell Biol 2018; 97:54-71. [PMID: 30171775 PMCID: PMC6378613 DOI: 10.1111/imcb.12200] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/28/2018] [Accepted: 08/28/2018] [Indexed: 12/11/2022]
Abstract
IL-33 is an IL-1-related cytokine that can act as an alarmin when released from necrotic cells. Once released, it can target various immune cells including mast cells, innate lymphoid cells and T cells to elicit a Th2-like immune response. We show here that bone marrow-derived mast cells produce IL-13, IL-6, TNF, GM-CSF, CCL3 and CCL4 in response to IL-33 stimulation. Inhibition of the p38 MAPK, or inhibition or knockout of its downstream kinases MK2 and MK3, blocked the production of these cytokines in response to IL-33. The mechanism downstream of MK2/3 was cytokine specific; however, MK2 and MK3 were able to regulate TNF and GM-CSF mRNA stability. Previous studies in macrophages have shown that MK2 regulates mRNA stability via phosphorylation of the RNA-binding protein TTP (Zfp36). The regulation of cytokine production in mast cells was, however, independent of TTP. MK2/3 were able to phosphorylate the TTP-related protein Brf1 (Zfp36 l1) in IL-33-stimulated mast cells, suggesting a mechanism by which MK2/3 might control mRNA stability in these cells. In line with its ability to regulate in vitro IL-33-stimulated cytokine production, double knockout of MK2 and 3 in mice prevented neutrophil recruitment following intraperitoneal injection of IL-33.
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Affiliation(s)
- Pierre C McCarthy
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK.,MRC Protein Phosphorylation Unit, School of Life Sciences, Sir James Black Centre, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Iain R Phair
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Corinna Greger
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Katerina Pardali
- Respiratory, Inflammation & Autoimmunity IMED Biotech Unit, AstraZeneca, Gothenburg, Mölndal, 43183, Sweden
| | - Victoria A McGuire
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK.,Photobiology Unit, Scottish Cutaneous Porphyria Service, Ninewells Hospital and Medical School, Dundee, DD1 9SY, UK
| | - Andrew R Clark
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Matthias Gaestel
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK.,Institute for Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover, 30623, Germany
| | - J Simon C Arthur
- Division of Cell Signalling and Immunology, School of Life Sciences, Wellcome Trust Building, University of Dundee, Dow St, Dundee, DD1 5EH, UK
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11
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Shi Q, Cai X, Shi G, Lv X, Yu J, Wang F. Interleukin-4 protects from chemotherapy-induced peripheral neuropathy in mice modal via the stimulation of IL-4/STAT6 signaling. Acta Cir Bras 2018; 33:491-498. [PMID: 30020310 DOI: 10.1590/s0102-865020180060000003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/14/2018] [Indexed: 01/13/2023] Open
Affiliation(s)
- Qingbin Shi
- Traditional Chinese Medicine Hospital, China
| | - Xiuying Cai
- Traditional Chinese Medicine Hospital, China
| | | | - Xingle Lv
- Traditional Chinese Medicine Hospital, China
| | - Jinping Yu
- Traditional Chinese Medicine Hospital, China
| | - Feng Wang
- Traditional Chinese Medicine Hospital, China
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12
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Guo J, Qu H, Chen Y, Xia J. The role of RNA-binding protein tristetraprolin in cancer and immunity. Med Oncol 2017; 34:196. [DOI: 10.1007/s12032-017-1055-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 11/06/2017] [Indexed: 12/20/2022]
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13
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Valladao AC, Frevert CW, Koch LK, Campbell DJ, Ziegler SF. STAT6 Regulates the Development of Eosinophilic versus Neutrophilic Asthma in Response to Alternaria alternata. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2016; 197:4541-4551. [PMID: 27815425 PMCID: PMC5136320 DOI: 10.4049/jimmunol.1600007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 10/11/2016] [Indexed: 11/19/2022]
Abstract
Human asthma is a heterogeneous disease characterized by the expression of both Th2 and Th17 cytokines. In vitro and in vivo studies have shown a reciprocal regulation between Th2 and Th17 pathways, suggesting a potential induction of neutrophil-promoting Th17 inflammation in the absence of a Th2 response. Alternaria alternata is a clinically relevant allergen that is associated with severe and fatal asthma exacerbations. Exposure to A. alternata is characterized by a predominant Th2 response, but can also induce the production of factors associated with Th17 responses (e.g., CXCL8) from epithelial cells. Using a mouse model, we found that wild-type mice develop an eosinophilic Th2 airway disease in response to A. alternata exposure, whereas IL-4-, IL-13-, and STAT6-deficient mice exhibit a primarily neutrophilic response. Neutrophilic asthma in STAT6-/- mice was accompanied by elevated lung levels of TNF-α, CXCL1, CXCL2, and CXCL5, and was steroid resistant. Neutralization of Th17 signaling only partially reduced neutrophil numbers and total airway inflammation. Airway neutrophilia developed in RAG-deficient and CD4-depleted BALB/c mice, suggesting that the suppression of neutrophil responses is dependent on Th2 cytokine production by T cells and that airway neutrophilia is primarily an innate response to allergen. These results highlight the importance of combination therapies for treatment of asthma and establish a role for factors other than IL-17 as targets for neutrophilic asthma.
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Affiliation(s)
- Andrea C Valladao
- Department of Immunology, University of Washington, Seattle, WA 98101
- Immunology Program, Benaroya Research Institute, Seattle, WA 98101; and
| | - Charles W Frevert
- Department of Comparative Medicine, University of Washington, Seattle, WA 98101
| | - Lisa K Koch
- Immunology Program, Benaroya Research Institute, Seattle, WA 98101; and
| | - Daniel J Campbell
- Department of Immunology, University of Washington, Seattle, WA 98101
- Immunology Program, Benaroya Research Institute, Seattle, WA 98101; and
| | - Steven F Ziegler
- Department of Immunology, University of Washington, Seattle, WA 98101;
- Immunology Program, Benaroya Research Institute, Seattle, WA 98101; and
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14
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Zhao XK, Che P, Cheng ML, Zhang Q, Mu M, Li H, Luo Y, Liang YD, Luo XH, Gao CQ, Jackson PL, Wells JM, Zhou Y, Hu M, Cai G, Thannickal VJ, Steele C, Blalock JE, Han X, Chen CY, Ding Q. Tristetraprolin Down-Regulation Contributes to Persistent TNF-Alpha Expression Induced by Cigarette Smoke Extract through a Post-Transcriptional Mechanism. PLoS One 2016; 11:e0167451. [PMID: 27911957 PMCID: PMC5135108 DOI: 10.1371/journal.pone.0167451] [Citation(s) in RCA: 8] [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: 08/21/2016] [Accepted: 11/14/2016] [Indexed: 12/19/2022] Open
Abstract
Rationale Tumor necrosis factor-alpha (TNF-α) is a potent pro-inflammatory mediator and its expression is up-regulated in chronic obstructive pulmonary disease (COPD). Tristetraprolin (TTP) is implicated in regulation of TNF-α expression; however, whether TTP is involved in cigarette smoke-induced TNF-α expression has not been determined. Methods TTP expression was examined by western blot analysis in murine alveolar macrophages and alveolar epithelial cells challenged without or with cigarette smoke extract (CSE). TNF-α mRNA stability, and the decay of TNF-α mRNA, were determined by real-time quantitative RT-PCR. TNF-α protein levels were examined at the same time in these cells. To identify the molecular mechanism involved, a construct expressing the human beta-globin reporter mRNA containing the TNF-α 3’-untranslated region was generated to characterize the TTP targeted site within TNF-α mRNA. Results CSE induced TTP down-regulation in alveolar macrophages and alveolar epithelial cells. Reduced TTP expression resulted in significantly increased TNF-α mRNA stability. Importantly, increased TNF-α mRNA stability due to impaired TTP function resulted in significantly increased TNF-α levels in these cells. Forced TTP expression abrogated the increased TNF-α mRNA stability and expression induced by CSE. By using the globin reporter construct containing TNF-α mRNA 3’-untranslated region, the data indicate that TTP directly targets the adenine- and uridine-rich region (ARE) of TNF-α mRNA and negatively regulates TNF-α expression at the post-transcriptional level. Conclusion The data demonstrate that cigarette smoke exposure reduces TTP expression and impairs TTP function, resulting in significantly increased TNF-α mRNA stability and excessive TNF-α expression in alveolar macrophages and epithelial cells. The data suggest that TTP is a novel post-transcriptional regulator and limits excessive TNF-α expression and inflammatory response induced by cigarette smoke.
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Affiliation(s)
- Xue-Ke Zhao
- Department of Infectious Diseases, The Hospital Affiliated to Guizhou Medical University, Guiyang, Guizhou, China
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Pulin Che
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Ming-Liang Cheng
- Department of Infectious Diseases, The Hospital Affiliated to Guizhou Medical University, Guiyang, Guizhou, China
- * E-mail: (MLC); (QD)
| | - Quan Zhang
- Department of Infectious Diseases, The Hospital Affiliated to Guizhou Medical University, Guiyang, Guizhou, China
| | - Mao Mu
- Department of Infectious Diseases, The Hospital Affiliated to Guizhou Medical University, Guiyang, Guizhou, China
| | - Hong Li
- Department of Infectious Diseases, The Hospital Affiliated to Guizhou Medical University, Guiyang, Guizhou, China
| | - Yuan Luo
- Department of Oral Surgery, Shanghai Stomatology Hospital, Fudan University, Shanghai, China
| | - Yue-Dong Liang
- Department of Infectious Diseases, Public Health Center of Guiyang, Guiyang, Guizhou, China
| | - Xin-Hua Luo
- Department of Infectious Diseases, People's Hospital of Guizhou Province, Guiyang, Guizhou, China
| | - Chang-Qing Gao
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Patricia L. Jackson
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - J. Michael Wells
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yong Zhou
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Meng Hu
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Guoqiang Cai
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Victor J. Thannickal
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Chad Steele
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - J. Edwin Blalock
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Xiaosi Han
- Neurology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Ching-Yi Chen
- Department of Biochemistry, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Qiang Ding
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail: (MLC); (QD)
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15
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Sedlyarov V, Fallmann J, Ebner F, Huemer J, Sneezum L, Ivin M, Kreiner K, Tanzer A, Vogl C, Hofacker I, Kovarik P. Tristetraprolin binding site atlas in the macrophage transcriptome reveals a switch for inflammation resolution. Mol Syst Biol 2016; 12:868. [PMID: 27178967 PMCID: PMC4988506 DOI: 10.15252/msb.20156628] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Precise regulation of mRNA decay is fundamental for robust yet not exaggerated inflammatory responses to pathogens. However, a global model integrating regulation and functional consequences of inflammation‐associated mRNA decay remains to be established. Using time‐resolved high‐resolution RNA binding analysis of the mRNA‐destabilizing protein tristetraprolin (TTP), an inflammation‐limiting factor, we qualitatively and quantitatively characterize TTP binding positions in the transcriptome of immunostimulated macrophages. We identify pervasive destabilizing and non‐destabilizing TTP binding, including a robust intronic binding, showing that TTP binding is not sufficient for mRNA destabilization. A low degree of flanking RNA structuredness distinguishes occupied from silent binding motifs. By functionally relating TTP binding sites to mRNA stability and levels, we identify a TTP‐controlled switch for the transition from inflammatory into the resolution phase of the macrophage immune response. Mapping of binding positions of the mRNA‐stabilizing protein HuR reveals little target and functional overlap with TTP, implying a limited co‐regulation of inflammatory mRNA decay by these proteins. Our study establishes a functionally annotated and navigable transcriptome‐wide atlas (http://ttp-atlas.univie.ac.at) of cis‐acting elements controlling mRNA decay in inflammation.
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Affiliation(s)
- Vitaly Sedlyarov
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Jörg Fallmann
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Florian Ebner
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Jakob Huemer
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Lucy Sneezum
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Masa Ivin
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Kristina Kreiner
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Andrea Tanzer
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Claus Vogl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ivo Hofacker
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria Center for non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg C, Denmark
| | - Pavel Kovarik
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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16
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Ganguly K, Giddaluru J, August A, Khan N. Post-transcriptional Regulation of Immunological Responses through Riboclustering. Front Immunol 2016; 7:161. [PMID: 27199986 PMCID: PMC4850162 DOI: 10.3389/fimmu.2016.00161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 04/15/2016] [Indexed: 12/22/2022] Open
Abstract
Immunological programing of immune cells varies in response to changing environmental signals. This process is facilitated by modifiers that regulate the translational fate of mRNAs encoding various immune mediators, including cytokines and chemokines, which in turn determine the rapid activation, tolerance, and plasticity of the immune system. RNA-binding proteins (RBPs) recruited by the specific sequence elements in mRNA transcripts are one such modifiers. These RBPs form RBP-RNA complexes known as "riboclusters." These riboclusters serve as RNA sorting machinery, where depending upon the composition of the ribocluster, translation, degradation, or storage of mRNA is controlled. Recent findings suggest that this regulation of mRNA homeostasis is critical for controlling the immune response. Here, we present the current knowledge of the ribocluster-mediated post-transcriptional regulation of immune mediators and highlight recent findings regarding their implications for the pathogenesis of acute or chronic inflammatory diseases.
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Affiliation(s)
- Koelina Ganguly
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad , Hyderabad , India
| | - Jeevan Giddaluru
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad , Hyderabad , India
| | - Avery August
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University , New York, NY , USA
| | - Nooruddin Khan
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad , Hyderabad , India
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17
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Inoue Y, Abe K, Onozaki K, Hayashi H. TGF-β decreases the stability of IL-18-induced IFN-γ mRNA through the expression of TGF-β-induced tristetraprolin in KG-1 cells. Biol Pharm Bull 2016; 38:536-44. [PMID: 25832634 DOI: 10.1248/bpb.b14-00673] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously reported that transforming growth factor-β (TGF-β) down-regulates interferon-γ (IFN-γ) production in an interleukin-18 (IL-18) treated mouse natural killer (NK) cell line, LNK5E6. In LNK5E6 cells, TGF-β exhibited no inhibition of the IL-18-induced transcription of IFN-γ, but did stimulate the degradation of IFN-γ mRNA induced by IL-18. In the present study, we investigated the mechanism of the down-regulatory effects of TGF-β on IFN-γ mRNA expression in a human myelomonocytic cell line, KG-1, which produces IFN-γ in response to IL-18 alone. Interestingly, IL-18 induced the production of the IFN-γ through the stabilization of IFN-γ mRNA, but not the enhanced transcription of IFN-γ gene. The stability of IFN-γ mRNA was regulated by mRNA destabilizing elements in the 3'untranslated region (UTR) of IFN-γ mRNA, especially adenylate-uridylate (AU)-rich elements (AREs) in the 5' half of 3'UTR. Tristetraprolin (TTP), one of the ARE-binding proteins, destabilizes IFN-γ mRNA, and IL-18 repressed the expression of TTP mRNA. Moreover, TGF-β repressed the IL-18-induced expression of IFN-γ mRNA through the induction of TTP mRNA to destabilize IFN-γ mRNA. Our data is the first to reveal that the crosstalk between IL-18 and TGF-β through the expression of TTP regulates the production of IFN-γ.
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Affiliation(s)
- Yasumichi Inoue
- Department of Drug Metabolism and Disposition, Graduate School of Pharmaceutical Sciences, Nagoya City University
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18
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Kovarik P, Ebner F, Sedlyarov V. Posttranscriptional regulation of cytokine expression. Cytokine 2015; 89:21-26. [PMID: 26586165 DOI: 10.1016/j.cyto.2015.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 01/20/2023]
Abstract
Expression of cytokines and chemokines is regulated at multiple steps during the transfer of the genetic information from DNA sequence to the functional protein. The multilayered control of cytokine expression reflects the need of the immune system to precisely and rapidly adjust the magnitude and duration of immune responses to external cues. Common features of the regulation of cytokine expression are temporal and highly dynamic changes in cytokine mRNA stability. Failures in the timing and extent of mRNA decay can result in disease. Recent advances in transcriptome-wide approaches began to shed light into the complex network of cis-acting sequence elements and trans-acting factors controlling mRNA stability. These approaches led to the discovery of novel unexpected paradigms but they also revealed new questions. This review will discuss the control of cytokine mRNA stability both in the context of high content approaches as well as focused mechanistic studies and animal models. The article highlights the need for systems biology approaches as important means to understand how cytokine mRNA decay helps maintain the immune and tissue homeostasis, and to explore options for therapeutical exploitation of mRNA stability regulation.
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Affiliation(s)
- Pavel Kovarik
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
| | - Florian Ebner
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
| | - Vitaly Sedlyarov
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
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19
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Brennan-Laun SE, Ezelle HJ, Li XL, Hassel BA. RNase-L control of cellular mRNAs: roles in biologic functions and mechanisms of substrate targeting. J Interferon Cytokine Res 2015; 34:275-88. [PMID: 24697205 DOI: 10.1089/jir.2013.0147] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
RNase-L is a mediator of type 1 interferon-induced antiviral activity that has diverse and critical cellular roles, including the regulation of cell proliferation, differentiation, senescence and apoptosis, tumorigenesis, and the control of the innate immune response. Although RNase-L was originally shown to mediate the endonucleolytic cleavage of both viral and ribosomal RNAs in response to infection, more recent evidence indicates that RNase-L also functions in the regulation of cellular mRNAs as an important mechanism by which it exerts its diverse biological functions. Despite this growing body of work, many questions remain regarding the roles of mRNAs as RNase-L substrates. This review will survey known and putative mRNA substrates of RNase-L, propose mechanisms by which it may selectively cleave these transcripts, and postulate future clinical applications.
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Affiliation(s)
- Sarah E Brennan-Laun
- 1 Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine , Baltimore, Maryland
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20
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Brennan-Laun SE, Li XL, Ezelle HJ, Venkataraman T, Blackshear PJ, Wilson GM, Hassel BA. RNase L attenuates mitogen-stimulated gene expression via transcriptional and post-transcriptional mechanisms to limit the proliferative response. J Biol Chem 2014; 289:33629-43. [PMID: 25301952 DOI: 10.1074/jbc.m114.589556] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cellular response to mitogens is tightly regulated via transcriptional and post-transcriptional mechanisms to rapidly induce genes that promote proliferation and efficiently attenuate their expression to prevent malignant growth. RNase L is an endoribonuclease that mediates diverse antiproliferative activities, and tristetraprolin (TTP) is a mitogen-induced RNA-binding protein that directs the decay of proliferation-stimulatory mRNAs. In light of their roles as endogenous proliferative constraints, we examined the mechanisms and functional interactions of RNase L and TTP to attenuate a mitogenic response. Mitogen stimulation of RNase L-deficient cells significantly increased TTP transcription and the induction of other mitogen-induced mRNAs. This regulation corresponded with elevated expression of serum-response factor (SRF), a master regulator of mitogen-induced transcription. RNase L destabilized the SRF transcript and formed a complex with SRF mRNA in cells providing a mechanism by which RNase L down-regulates SRF-induced genes. TTP and RNase L proteins interacted in cells suggesting that RNase L is directed to cleave TTP-bound RNAs as a mechanism of substrate specificity. Consistent with their concerted function in RNA turnover, the absence of either RNase L or TTP stabilized SRF mRNA, and a subset of established TTP targets was also regulated by RNase L. RNase L deficiency enhanced mitogen-induced proliferation demonstrating its functional role in limiting the mitogenic response. Our findings support a model of feedback regulation in which RNase L and TTP target SRF mRNA and SRF-induced transcripts. Accordingly, meta-analysis revealed an enrichment of RNase L and TTP targets among SRF-regulated genes suggesting that the RNase L/TTP axis represents a viable target to inhibit SRF-driven proliferation in neoplastic diseases.
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Affiliation(s)
- Sarah E Brennan-Laun
- From the Marlene and Stewart Greenebaum Cancer Center, Departments of Microbiology and Immunology and
| | - Xiao-Ling Li
- the Genetics Branch, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Heather J Ezelle
- From the Marlene and Stewart Greenebaum Cancer Center, Departments of Microbiology and Immunology and the Research Services, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201, and
| | | | - Perry J Blackshear
- the Laboratory of Signal Transduction, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Gerald M Wilson
- From the Marlene and Stewart Greenebaum Cancer Center, Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Bret A Hassel
- From the Marlene and Stewart Greenebaum Cancer Center, Departments of Microbiology and Immunology and the Research Services, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201, and
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21
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Kafasla P, Skliris A, Kontoyiannis DL. Post-transcriptional coordination of immunological responses by RNA-binding proteins. Nat Immunol 2014; 15:492-502. [PMID: 24840980 DOI: 10.1038/ni.2884] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/01/2014] [Indexed: 12/22/2022]
Abstract
Immunological reactions are propelled by ever-changing signals that alter the translational ability of the RNA in the cells involved. Such alterations are considered to be consequential modifications in the transcriptomic decoding of the genetic blueprint. The identification of RNA-binding protein (RBP) assemblies engaged in the coordinative regulation of state-specific RNAs indicates alternative and exclusive means for determining the activation, plasticity and tolerance of cells of the immune system. Here we review current knowledge about RBP-regulated post-transcriptional events involved in the reactivity of cells of the immune system and the importance of their alteration during chronic inflammatory pathology and autoimmunity.
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Affiliation(s)
- Panagiota Kafasla
- Division of Immunology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
| | - Antonis Skliris
- Division of Immunology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
| | - Dimitris L Kontoyiannis
- Division of Immunology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
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22
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Klementiev B, Enevoldsen MN, Li S, Carlsson R, Liu Y, Issazadeh-Navikas S, Bock E, Berezin V. Antiinflammatory properties of a peptide derived from interleukin-4. Cytokine 2013; 64:112-21. [PMID: 23972727 DOI: 10.1016/j.cyto.2013.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/19/2013] [Accepted: 07/20/2013] [Indexed: 12/23/2022]
Abstract
Interleukin-4 (IL-4) is a potent antiinflammatory cytokine. However its use in the clinic is hampered by side effects. We here describe the identification of a novel synthetic peptide, termed Ph8, derived from α-helix C of IL-4, which interacts with IL-4 receptor α (IL-4Rα). Employing various cultured genetically engineered cell lines and primary lymphocytes, surface plasmon resonance, qPCR, ELISA and immunoblotting techniques we found that Ph8 bound IL-4Rα and mimicked the anti-inflammatory effects of IL-4 by inhibiting TNF-α production by macrophages in vitro. It induced phosphorylation of STAT6 65kD but inhibited phosphorylation of STAT6 110 kD induced by IL-4 in a B-cell line that expressed the type I receptor. It also inhibited the IL-4-stimulated expression of a STAT6-inducible reporter gene in cells that expressed the type II receptor. Ph8 inhibited the proliferation of Th1/2 cells and downregulated the production of IFN-γ in stimulated Th1 cells. Moreover, Ph8 did not induce any shift in Th1/Th2 profile. This is a favorable effect and it is indicating that Ph8 could block general T cell activation and inflammatory responses without further inducing the side effects generally associated with IL-4 signaling. These data collectively show that Ph8 is only a partial agonist of IL-4 mimicking its desirable properties. In agreement, Ph8 treatment of rats with collagen-induced arthritis, a Th1- and antibody- mediated disease of joint, delayed the manifestation of chronic inflammation and reduced acute inflammation in carrageenan-induced edema. Our findings indicate that Ph8 is a promising potential drug candidate for the treatment of inflammatory diseases.
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Affiliation(s)
- Boris Klementiev
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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23
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Hochdörfer T, Tiedje C, Stumpo DJ, Blackshear PJ, Gaestel M, Huber M. LPS-induced production of TNF-α and IL-6 in mast cells is dependent on p38 but independent of TTP. Cell Signal 2013; 25:1339-47. [PMID: 23499908 DOI: 10.1016/j.cellsig.2013.02.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 02/26/2013] [Indexed: 02/08/2023]
Abstract
The production of the proinflammatory cytokines TNF-α and IL-6 is regulated by various mRNA-binding proteins, influencing stability and translation of the respective transcripts. Research in macrophages has shown the importance of the p38-MK2-tristetraprolin (TTP) axis for regulation of TNF-α mRNA stability and translation. In the current study we examined a possible involvement of p38 and TTP in LPS-induced cytokine production in bone marrow-derived mast cells (BMMCs). Using pharmacological inhibitors we initially found a strong dependence of LPS-induced TNF-α and IL-6 production on p38 activation, whereas activation of the Erk pathway appeared dispensable. LPS treatment also induced p38-dependent expression of the TTP gene. This prompted us to analyze the proinflammatory cytokine response in BMMCs generated from TTP-deficient mice. Unexpectedly, there were no significant differences in cytokine production between TTP-deficient and WT BMMCs in response to LPS. Gene expression and cytokine production of TNF-α and IL-6 as well as stability of the TNF-α transcript were comparable between TTP-deficient and WT BMMCs. In contrast to TTP mRNA expression, TTP protein expression could not be detected in BMMCs. While we successfully precipitated and detected TTP from lysates of LPS-stimulated RAW 264.7 macrophages, this was not accomplished from BMMC lysates. In contrast, we found mRNA and protein expressions of the other TIS11 family members connected to regulation of mRNA stability, BRF1 and BRF2, and detected their interaction with 14-3-3 proteins. These data suggest that control of cytokine mRNA stability and translation in MCs is exerted by proteins different from TTP.
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Affiliation(s)
- Thomas Hochdörfer
- RWTH Aachen University, Medical Faculty, Institute of Biochemistry and Molecular Immunology, Aachen, Germany
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24
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Chen YL, Jiang YW, Su YL, Lee SC, Chang MS, Chang CJ. Transcriptional regulation of tristetraprolin by NF-κB signaling in LPS-stimulated macrophages. Mol Biol Rep 2012; 40:2867-77. [PMID: 23212617 DOI: 10.1007/s11033-012-2302-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 11/19/2012] [Indexed: 01/11/2023]
Affiliation(s)
- Yu-Ling Chen
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
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25
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Abe K, Ishigami T, Shyu AB, Ohno S, Umemura S, Yamashita A. Analysis of interferon-beta mRNA stability control after poly(I:C) stimulation using RNA metabolic labeling by ethynyluridine. Biochem Biophys Res Commun 2012; 428:44-9. [PMID: 23063848 DOI: 10.1016/j.bbrc.2012.09.144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 09/30/2012] [Indexed: 12/18/2022]
Abstract
Interferon-beta (IFN-β) is a critical antiviral cytokine and is essential for innate and acquired immune responses to pathogens. Treatment with polyinosinic:polycytidylic acid (poly(I:C)) induces transient accumulation of IFN-β mRNA, which involves an increase and a decrease of IFN-β mRNA. This phenomenon has been extensively analyzed as a model for understanding the mechanisms of transient gene induction in response to external stimuli. Using a new RNA metabolic labeling method with ethynyluridine to directly measure de novo RNA synthesis and RNA stability, we reassessed both de novo synthesis and degradation of IFN-β mRNA. We found that transcriptional activity is maintained after the maximum accumulation of IFN-β mRNA following poly(I:C) treatment on immortalized human bronchial epithelial cells. We also observed an unexpected change in the stability of IFN-β mRNA before and after the maximum accumulation. The results indicate that this method of RNA metabolic labeling provides a general approach for the simultaneous analysis of transcriptional activity and mRNA stability coupled with transcriptional timing.
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Affiliation(s)
- Kaito Abe
- Department of Cardiology, Yokohama City University School of Medicine, 3-9, Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan.
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Goddio MV, Gattelli A, Slomiansky V, Lacunza E, Gingerich T, Tocci JM, Facchinetti MM, Curino AC, LaMarre J, Abba MC, Kordon EC. Mammary differentiation induces expression of Tristetraprolin, a tumor suppressor AU-rich mRNA-binding protein. Breast Cancer Res Treat 2012; 135:749-58. [PMID: 22968621 DOI: 10.1007/s10549-012-2216-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 08/13/2012] [Indexed: 12/31/2022]
Abstract
Tristetraprolin (TTP) is a RNA-binding protein that inhibits the expression of pro-inflammatory cytokines and invasiveness-associated genes. TTP levels are decreased in many different cancer types and it has been proposed that this protein could be used as a prognostic factor in breast cancer. Here, using publicly available DNA microarray datasets, "serial analysis of gene expression" libraries and qRT-PCR analysis, we determined that TTP mRNA is present in normal breast cells and its levels are significantly decreased in all breast cancer subtypes. In addition, by immunostaining, we found that TTP expression is higher in normal breast tissue and benign lesions than in infiltrating carcinomas. Among these, lower grade tumors showed increased TTP expression compared to higher grade cancers. Therefore, these data indicate that TTP protein levels would provide a better negative correlation with breast cancer invasiveness than TTP transcript levels. In mice, we found that TTP mRNA and protein expression is also diminished in mammary tumors. Interestingly, a strong positive association of TTP expression and mammary differentiation was identified in normal and tumor cells. In fact, TTP expression is highly increased during lactation, showing good correlation with various mammary differentiation factors. TTP expression was also induced in mammary HC11 cells treated with lactogenic hormones, mainly by prolactin, through Stat5A activation. The effect of this hormone was highly dependent on mammary differentiation status, as prolactin was unable to elicit a similar response in proliferating or neoplastic mammary cells. In summary, these studies show that TTP expression is strongly linked to the mammary differentiation program in human and mice, suggesting that this protein might play specific and relevant roles in the normal physiology of the gland.
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Affiliation(s)
- M Victoria Goddio
- LEGMA, IFIBYNE-CONICET, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Gaba A, Grivennikov SI, Do MV, Stumpo DJ, Blackshear PJ, Karin M. Cutting edge: IL-10-mediated tristetraprolin induction is part of a feedback loop that controls macrophage STAT3 activation and cytokine production. THE JOURNAL OF IMMUNOLOGY 2012; 189:2089-93. [PMID: 22865915 DOI: 10.4049/jimmunol.1201126] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In activated macrophages, the anti-inflammatory cytokine IL-10 inhibits expression of molecules that propagate inflammation in a manner that depends on transcription factor STAT3. Expression of IL-10 is regulated posttranscriptionally by the RNA-binding protein tristetraprolin (TTP), which destabilizes IL-10 mRNA in activated macrophages. Using LPS-activated bone marrow-derived murine macrophages, we demonstrate that TTP is a negative regulator of the IL-10/STAT3 anti-inflammatory response. LPS-stimulated TTP-deficient macrophages overproduced IL-10, contained increased amounts of activated STAT3, and showed reduced expression of inflammatory cytokines, including cytokines encoded by TTP target mRNAs. Thus, in LPS-stimulated TTP-deficient macrophages, increased IL-10/STAT3 anti-inflammatory control was dominant over the mRNA stabilization of specific TTP targets. The TTP gene promoter contains a conserved STAT3 binding site, and IL-10 induces STAT3 recruitment to this site. Correspondingly, STAT3 was required for efficient IL-10-induced TTP expression. Hence, by inducing TTP expression, STAT3 activates a negative regulatory loop that controls the IL-10/STAT3 anti-inflammatory response.
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Affiliation(s)
- Anthony Gaba
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
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Florkowska M, Tymoszuk P, Balwierz A, Skucha A, Kochan J, Wawro M, Stalinska K, Kasza A. EGF activates TTP expression by activation of ELK-1 and EGR-1 transcription factors. BMC Mol Biol 2012; 13:8. [PMID: 22433566 PMCID: PMC3342124 DOI: 10.1186/1471-2199-13-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 03/20/2012] [Indexed: 01/04/2023] Open
Abstract
Background Tristetraprolin (TTP) is a key mediator of processes such as inflammation resolution, the inhibition of autoimmunity and in cancer. It carries out this role by the binding and degradation of mRNA transcripts, thereby decreasing their half-life. Transcripts modulated by TTP encode proteins such as cytokines, pro-inflammatory agents and immediate-early response proteins. TTP can also modulate neoplastic phenotypes in many cancers. TTP is induced and functionally regulated by a spectrum of both pro- and anti-inflammatory cytokines, mitogens and drugs in a MAPK-dependent manner. So far the contribution of p38 MAPK to the regulation of TTP expression and function has been best described. Results Our results demonstrate the induction of the gene coding TTP (ZFP36) by EGF through the ERK1/2-dependent pathway and implicates the transcription factor ELK-1 in this process. We show that ELK-1 regulates ZFP36 expression by two mechanisms: by binding the ZFP36 promoter directly through ETS-binding site (+ 883 to +905 bp) and by inducing expression of EGR-1, which in turn increases ZFP36 expression through sequences located between -111 and -103 bp. Conclusions EGF activates TTP expression via ELK-1 and EGR-1 transcription factors.
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Suzuki K, Murphy SH, Xia Y, Yokota M, Nakagomi D, Liu F, Verma IM, Nakajima H. Tumor suppressor p53 functions as a negative regulator in IgE-mediated mast cell activation. PLoS One 2011; 6:e25412. [PMID: 21966524 PMCID: PMC3179515 DOI: 10.1371/journal.pone.0025412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/02/2011] [Indexed: 01/22/2023] Open
Abstract
Mast cells are known to play a pivotal role in allergic diseases such as allergic rhinitis, asthma, and atopic dermatitis by releasing granules containing histamine, LTC4, and other preformed chemical mediators. Previous reports have demonstrated that IKK2 (also called IKKβ), a central intracellular component of NF-κB activation pathways, plays a critical role in IgE-mediated degranulation of mast cells and anaphylaxis in mice. In this study, we show that protein levels of tumor suppressor p53 are up-regulated upon IgE-mediated activation in mast cells and lack of p53 results in enhanced responses in both early and late phase anaphylaxis. p53 inhibits not only the catalytic activity of IKK2 presumably through the modulation of glycosylation but also p65 (RelA)-mediated transactivation. Our findings are the first to demonstrate that p53 functions as a negative regulator in mast cells.
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Affiliation(s)
- Kotaro Suzuki
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California, United States of America.
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Yin K, Deng X, Mo ZC, Zhao GJ, Jiang J, Cui LB, Tan CZ, Wen GB, Fu Y, Tang CK. Tristetraprolin-dependent post-transcriptional regulation of inflammatory cytokine mRNA expression by apolipoprotein A-I: role of ATP-binding membrane cassette transporter A1 and signal transducer and activator of transcription 3. J Biol Chem 2011; 286:13834-45. [PMID: 21339300 DOI: 10.1074/jbc.m110.202275] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Atherosclerosis is an inflammatory disease characterized by the accumulation of macrophages in the arterial intima. The activated macrophages secreted more pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, which promote the development of the disease. Apolipoprotein A-I (apoA-I), the major component of high density lipoprotein, is involved in reverse cholesterol transport of lipid metabolism. Recently, it has been found that apoA-I suppresses inflammation via repression of inflammatory cytokine expression; the mechanisms of the apoA-I-suppressive action, however, are not yet well characterized. In this study, we have for the first time found that apoA-I suppresses the expression of some inflammatory cytokines induced by lipopolysaccharide via a specific post-transcriptional regulation process, namely mRNA destabilization, in macrophages. Our further studies have also shown that AU-rich elements in the 3'-untranslated region of TNF-α mRNA are responsive to the apoA-I-mediated mRNA destabilization. The apoA-I-induced inflammatory cytokine mRNA destabilization was associated with increased expression of mRNA-destabilizing protein tristetraprolin through a JAK2/STAT3 signaling pathway-dependent manner. When blocking interaction of apoA-I with ATP-binding membrane cassette transporter A1 (ABCA1), a major receptor for apoA-I in macrophages, it would almost totally abolish the effect of apoA-I on tristetraprolin expression. These results present not only a novel mechanism for the apoA-I-mediated inflammation suppression in macrophages but also provide new insights for developing strategies for modulating vascular inflammation and atherosclerosis.
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Affiliation(s)
- Kai Yin
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Life Science Research Center, University of South China, Hengyang, 421001, China
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Iida K, Suzuki K, Yokota M, Nakagomi D, Wakashin H, Iwata A, Kawashima H, Takatori H, Nakajima H. STAT4 Is Required for IFN-β-Induced MCP-1 mRNA Expression in Murine Mast Cells. Int Arch Allergy Immunol 2011; 155 Suppl 1:71-6. [DOI: 10.1159/000327300] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Khera TK, Dick AD, Nicholson LB. Mechanisms of TNFα regulation in uveitis: Focus on RNA-binding proteins. Prog Retin Eye Res 2010; 29:610-21. [DOI: 10.1016/j.preteyeres.2010.08.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Effects of mitochondrial dysfunction on the immunological properties of microglia. J Neuroinflammation 2010; 7:45. [PMID: 20701773 PMCID: PMC2925359 DOI: 10.1186/1742-2094-7-45] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 08/11/2010] [Indexed: 02/03/2023] Open
Abstract
Background Neurodegenerative diseases are characterized by both mitochondrial dysfunction and activation of microglia, the macrophages of the brain. Here, we investigate the effects of mitochondrial dysfunction on the activation profile of microglial cells. Methods We incubated primary mouse microglia with the mitochondrial toxins 3-nitropropionic acid (3-NP) or rotenone. These mitochondrial toxins are known to induce neurodegeneration in humans and in experimental animals. We characterized lipopolysaccharide- (LPS-) induced microglial activation and the alternative, interleukin-4- (IL-4-) induced microglial activation in these mitochondrial toxin-treated microglial cells. Results We found that, while mitochondrial toxins did not affect LPS-induced activation, as measured by release of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β), they did inhibit part of the IL-4-induced alternative activation, as measured by arginase activity and expression, induction of insulin-like growth factor 1 (IGF-1) and the counteraction of the LPS induced cytokine release. Conclusions Mitochondrial dysfunction in microglial cells inhibits part of the IL-4-induced alternative response. Because this alternative activation is considered to be associated with wound healing and an attenuation of inflammation, mitochondrial dysfunction in microglial cells might contribute to the detrimental effects of neuroinflammation seen in neurodegenerative diseases.
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Hacker C, Valchanova R, Adams S, Munz B. ZFP36L1 is regulated by growth factors and cytokines in keratinocytes and influences their VEGF production. Growth Factors 2010; 28:178-90. [PMID: 20166898 DOI: 10.3109/08977190903578660] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Keratinocyte-derived growth factors and cytokines play an important role in epidermal homeostasis and particularly in cutaneous wound repair. Thus, we analyzed a potential role of the ZFP36/tristetraprolin family of zinc finger proteins, which are targets of these factors, but also regulate their production, in keratinocytes. We show that expression of ZFP36, ZFP36L1, and ZFP36L2 is induced by a broad variety of growth factors and cytokines, and by scratch wounding. Since ZFP36L1 is a modulator of vascular endothelium growth factor (VEGF) mRNA stability, we subsequently used siRNA technology to inhibit ZFP36L1 gene expression. Notably, this treatment resulted in prolonged maintenance of elevated VEGF levels in HaCaT keratinocytes upon epidermal growth factor stimulation of these cells. Taken together, our results suggest an important role of ZFP36L1 in wound healing.
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Affiliation(s)
- Christine Hacker
- Institute of Physiology, Charité - University Medicine Berlin, Arnimallee 22, D-14195, Berlin, Germany
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The RNA binding protein tristetraprolin influences the activation state of murine dendritic cells. Mol Immunol 2009; 47:1161-70. [PMID: 19945750 DOI: 10.1016/j.molimm.2009.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 09/15/2009] [Accepted: 11/03/2009] [Indexed: 01/07/2023]
Abstract
Dendritic cells (DCs) serve to maintain peripheral tolerance under steady state conditions. Upon triggering by activation signals they initiate strong immune responses. The activation of DCs is accompanied by a rapid upregulation of proinflammatory cytokines, which were shown in other cell types to be regulated by mechanisms at the transcriptional and posttranscriptional level. Tristetraprolin (TTP), an important RNA binding protein, is involved in the regulation of mRNA stability of such cytokines. In this study we analyzed the significance of TTP for mouse DCs, which were derived from TTP(-/-) and WT bone marrow progenitor cells (BM-DCs). Unstimulated BM-DCs of TTP(-/-) mice expressed lower levels of mRNAs encoding the costimulatory molecules CD40 and CD86 and surprisingly also the canonical TTP targets TNF-alpha and IL-10 as compared with WT DCs. On the protein level, both DC populations expressed comparable amounts of CD80 and CD86 and of either cytokine, but TTP(-/-) DCs expressed less MHCII than WT DCs. On the other hand, TTP(-/-) DCs displayed elevated expression of other TTP target mRNAs like IL-1beta, c-fos and Mkp-1. Stimulation of BM-DCs of either genotype with lipopolysaccharide resulted in a rapid upregulation to a comparable extent of all molecules monitored so far, except for c-fos mRNA. Subsequent mRNA decay analysis revealed gene-specific differences in mRNA stability, which was influenced by the presence of TTP and the activation state of the DCs. Unstimulated TTP(-/-) DCs exerted a markedly lower allogeneic T cell stimulatory potential than WT DCs. Moreover, TTP(-/-) DCs induced an altered cytokine pattern in cocultures of DCs and T cells. However, allogeneic T cells primed by unstimulated DCs of either genotype were equally refractory to restimulation and suppressed the proliferation of naive T cells to the same extent. Thus, the findings of this study lend support to the interpretation that without external stimulation antigen presenting activity in DCs in the presence of TTP is more pronounced than in its absence and that posttranscriptional regulation contributes to the control of gene expression in DCs.
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Yu M, Moreno JL, Stains JP, Keegan AD. Complex regulation of tartrate-resistant acid phosphatase (TRAP) expression by interleukin 4 (IL-4): IL-4 indirectly suppresses receptor activator of NF-kappaB ligand (RANKL)-mediated TRAP expression but modestly induces its expression directly. J Biol Chem 2009; 284:32968-79. [PMID: 19801646 DOI: 10.1074/jbc.m109.001016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interleukin 4 (IL-4) inhibits receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast formation and functional activity in a STAT6-dependent manner. IL-4 down-regulates expression of tartrate-resistant acid phosphatase (TRAP) in mature osteoclasts. To determine whether IL-4 regulates TRAP promoter activity, RAW264.7 cells were transfected with a TRAP promoter-luciferase reporter. Treatment with IL-4 alone modestly enhanced TRAP luciferase activity. However, IL-4 suppressed the ability of RANKL to up-regulate TRAP-luciferase activity, suggesting that IL-4 has multiple effects on TRAP transcription. IL-4 also reduced the RANKL-induced association of RNA polymerase II with the TRAP gene in osteoclasts. The TRAP promoter contains a STAT6-binding motif, and STAT6 bound to the endogenous TRAP promoter after IL-4 treatment. To determine the impact of STAT6 binding, we transfected cells with STAT6VT, a constitutively active STAT6 mutant. STAT6VT alone up-regulated TRAP-luciferase activity; this effect was abrogated by mutating the STAT6 binding site in the minimal TRAP promoter. STAT6VT did not inhibit the potent up-regulation of TRAP promoter activity caused by overexpression of NFATc1, PU.1, and microphthalmia transcription factor, downstream targets of macrophage colony-stimulating factor and RANKL. IL-4 down-regulated the expression of c-Fos and NFATc1 in mature osteoclasts. Knockdown of NFATc1 by short interfering RNA caused TRAP expression to be down-regulated, and ectopic expression of NFATc1 abrogated the IL-4-induced down-regulation of TRAP. These results suggest that STAT6 plays two distinct roles in TRAP expression. The IL-4-induced activation of STAT6 mediates suppression of the RANKL-induced TRAP promoter activity indirectly by inhibiting NFATc1 expression. However, in the absence of RANKL and osteoclast differentiation, STAT6 binds the TRAP promoter after IL-4 treatment and directly enhances TRAP expression.
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Affiliation(s)
- Minjun Yu
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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TIS11 family proteins and their roles in posttranscriptional gene regulation. J Biomed Biotechnol 2009; 2009:634520. [PMID: 19672455 PMCID: PMC2722025 DOI: 10.1155/2009/634520] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 05/18/2009] [Indexed: 12/20/2022] Open
Abstract
Posttranscriptional regulation of gene expression of mRNAs containing adenine-uridine rich elements (AREs) in their 3′ untranslated regions is mediated by a number of different proteins that interact with these elements to either stabilise or destabilise them. The present review concerns the TPA-inducible sequence 11 (TIS11) protein family, a small family of proteins, that appears to interact with ARE-containing mRNAs and promote their degradation. This family of proteins has been extensively studied in the past decade. Studies have focussed on determining their biochemical functions, identifying their target mRNAs, and determining their roles in cell functions and diseases.
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Schaljo B, Kratochvill F, Gratz N, Sadzak I, Sauer I, Hammer M, Vogl C, Strobl B, Müller M, Blackshear PJ, Poli V, Lang R, Murray PJ, Kovarik P. Tristetraprolin is required for full anti-inflammatory response of murine macrophages to IL-10. THE JOURNAL OF IMMUNOLOGY 2009; 183:1197-206. [PMID: 19542371 DOI: 10.4049/jimmunol.0803883] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
IL-10 is essential for inhibiting chronic and acute inflammation by decreasing the amounts of proinflammatory cytokines made by activated macrophages. IL-10 controls proinflammatory cytokine and chemokine production indirectly via the transcription factor Stat3. One of the most physiologically significant IL-10 targets is TNF-alpha, a potent proinflammatory mediator that is the target for multiple anti-TNF-alpha clinical strategies in Crohn's disease and rheumatoid arthritis. The anti-inflammatory effects of IL-10 seem to be mediated by several incompletely understood transcriptional and posttranscriptional mechanisms. In this study, we show that in LPS-activated bone marrow-derived murine macrophages, IL-10 reduces the mRNA and protein levels of TNF-alpha and IL-1alpha in part through the RNA destabilizing factor tristetraprolin (TTP). TTP is known for its central role in destabilizing mRNA molecules containing class II AU-rich elements in 3' untranslated regions. We found that IL-10 initiates a Stat3-dependent increase of TTP expression accompanied by a delayed decrease of p38 MAPK activity. The reduction of p38 MAPK activity releases TTP from the p38 MAPK-mediated inhibition, thereby resulting in diminished mRNA and protein levels of proinflammatory cytokines. These findings establish that TTP is required for full responses of bone marrow-derived murine macrophages to IL-10.
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Affiliation(s)
- Barbara Schaljo
- Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, Vienna, Austria
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Parthasarathy G, Mansfield LS. Recombinant interleukin-4 enhances Campylobacter jejuni invasion of intestinal pig epithelial cells (IPEC-1). Microb Pathog 2009; 47:38-46. [PMID: 19409975 DOI: 10.1016/j.micpath.2009.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 03/10/2009] [Accepted: 04/21/2009] [Indexed: 12/19/2022]
Abstract
Campylobacter jejuni, a leading cause of bacterial gastroenteritis, has a diverse spectrum of disease expression. Polymicrobial infections may contribute to this, such as Trichuris, which elicits type 2 cytokines (including IL-4) and downregulates type 1 immunity. In previous studies, gnotobiotic piglets infected with C. jejuni and Trichuris suis had bloody diarrhea and marked gastrointestinal pathology, including bacterial invasion into epithelial cells and macrophages. Neonatal swine given these dual infections had elevated IL-4 and IL-10 responses in feces. In the studies reported here, we hypothesized that IL-4 or IL-10 enhances invasion of intestinal pig epithelial cells (IPEC-1) by C. jejuni. 10-14-day-old IPEC-1 cells were pretreated with recombinant IL-4 (rIL-4) or rIL-10 for 5h and then challenged with C. jejuni. Cells pretreated with rIL-4 were viable and showed approximately 6-fold increases in C. jejuni (but not Escherichia coli DH5alpha) internalization compared to cells with no pretreatment. Enhanced C. jejuni invasion was rIL-4 dose-dependent and reversed by addition of anti-IL-4 antibody. Preincubation with rIL-10 did not significantly alter C. jejuni internalization. Transepithelial electrical resistance (TEER) was significantly reduced following rIL-4 treatment, but not rIL-10 treatment. After rIL-4 pretreatment and C. jejuni challenge, light microscopy showed vacuolated cells with damaged paracellular junctions. Transmission electron microscopy (TEM) showed multiple internalized bacteria. Most were in the cytoplasm, but some were within or adjacent to vacuoles. We conclude that rIL-4 damages paracellular junctions and alters the physiology of these epithelial cells allowing increased invasion of C. jejuni.
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Affiliation(s)
- G Parthasarathy
- Department of Microbiology and Molecular Genetics, Comparative Enteric Diseases Laboratory, National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI 48824, USA
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Kagami SI, Owada T, Kanari H, Saito Y, Suto A, Ikeda K, Hirose K, Watanabe N, Iwamoto I, Nakajima H. Protein geranylgeranylation regulates the balance between Th17 cells and Foxp3+ regulatory T cells. Int Immunol 2009; 21:679-89. [DOI: 10.1093/intimm/dxp037] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Wang L, van Panhuys N, Hu-Li J, Kim S, Le Gros G, Min B. Blimp-1 induced by IL-4 plays a critical role in suppressing IL-2 production in activated CD4 T cells. THE JOURNAL OF IMMUNOLOGY 2008; 181:5249-56. [PMID: 18832679 DOI: 10.4049/jimmunol.181.8.5249] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although an inhibitory function of IL-4 in CD4 T cell IL-2 production has long been recognized, a mechanism mediating the inhibition remains unclear. In this study we demonstrate that IL-4 displays a potent suppressive function in IL-2 production of activated CD4 T cells through STAT6. IL-4-induced IL-2 suppression required IL-2 because IL-2 neutralization restored the production of IL-2 even in the presence of IL-4. In vivo, enhanced IL-2 production was found in nematode-infected IL-4- or STAT6-deficient animals, whereas immunization in the presence of IL-4 substantially diminished IL-2 production by Ag-specific CD4 T cells. IL-2 mRNA expression was reduced when T cells were stimulated in the presence of IL-4, whereas IL-2 mRNA decay was unaltered, suggesting that IL-4 mediates the suppression at a transcriptional level. Blimp-1 induced by IL-4 stimulation in activated CD4 T cells was found to be necessary to mediate the IL-2 inhibition as IL-4-mediated IL-2 suppression was less pronounced in activated CD4 T cells deficient in Blimp-1. Taken together, our results demonstrate a potential link with IL-4, Blimp-1, and IL-2 production, suggesting that Blimp-1 may play an important role in controlling IL-2 production in activated T cells and in adaptive T cell immunity.
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Affiliation(s)
- Lu Wang
- Department of Immunology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Abstract
Mast cells are the progeny of hematopoietic stem cells, and murine mast cells are usually divided into two distinct populations, mucosal mast cells (MMCs) and connective tissue-type mast cells (CTMCs). We previously reported that CTMCs expressed signal transducer and activator of transcription (Stat) 4, but MMCs did not. Stat4 is also expressed in T cells and plays important roles in their homeostasis. In the present study, we show that Stat4 is involved in the homeostasis of CTMCs. The number of skin CTMCs increased in Stat4-deficient Balb/c mice, but that of gastric MMCs did not, when compared to those in control Balb/c(+/+) mice. The comparison between cultured Stat4-deficient CTMCs and cultured Balb/c(+/+) CTMCs revealed that cell cycle progression and cyclin D3 expression in the cultured Stat4-deficient CTMCs were enhanced in a Stat3 activation-dependent manner. This phenotype was explained by upregulation of KitL-induced interleukin (IL)-6 acting in an autocrine manner in cultured Stat4-deficient CTMCs. These results show that Stat4 suppresses the proliferation of CTMCs by controlling IL-6 via an autocrine mechanism.
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Kagami SI, Kanari H, Suto A, Fujiwara M, Ikeda K, Hirose K, Watanabe N, Iwamoto I, Nakajima H. HMG-CoA reductase inhibitor simvastatin inhibits proinflammatory cytokine production from murine mast cells. Int Arch Allergy Immunol 2008; 146 Suppl 1:61-6. [PMID: 18504409 DOI: 10.1159/000126063] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a key rate-limiting enzyme in the mevalonate pathway. Accumulating data suggest that statins exhibit anti-inflammatory effects on a number of experimental models including experimental autoimmune encephalomyelitis and antigen-induced allergic airway inflammation. However, the mechanism underlying the anti-inflammatory effect of statins is still largely unknown. In this study, we examined the effect of a representative statin, simvastatin, on proinflammatory cytokine production from murine mast cells. METHODS Bone marrow-derived mast cells (BMMCs) were stimulated with lipopolysaccharide (LPS) in the presence or absence of simvastatin, and TNF-alpha and IL-6 production from BMMCs was evaluated at mRNA and protein levels. The effect of simvastatin on the expression of tristetraprolin, an RNA-binding protein that promotes decay of TNF-alpha mRNA, was evaluated. RESULTS Incubation of BMMCs with simvastatin resulted in the inhibition of LPS-induced TNF-alpha production at both mRNA and protein levels. Simvastatin also inhibited IL-6 production from LPS-stimulated BMMCs. However, simvastatin did not enhance the expression of tristetraprolin. CONCLUSIONS Simvastatin inhibits the production of TNF-alpha and IL-6 from activated mast cells in part by inhibiting de novo synthesis of their transcripts and the inhibition may account for the anti-inflammatory effect of simvastatin.
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Affiliation(s)
- Shin-ichiro Kagami
- Department of Molecular Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
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Frasca D, Landin AM, Alvarez JP, Blackshear PJ, Riley RL, Blomberg BB. Tristetraprolin, a negative regulator of mRNA stability, is increased in old B cells and is involved in the degradation of E47 mRNA. THE JOURNAL OF IMMUNOLOGY 2007; 179:918-27. [PMID: 17617583 DOI: 10.4049/jimmunol.179.2.918] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that the E2A-encoded transcription factor E47, which regulates class switch in splenic B cells, is down-regulated in old B cells, due to increased E47 mRNA decay. At least part of the decreased stability of E47 mRNA seen in aged B cells is mediated by proteins. We have herein looked at the specific proteins responsible for the degradation of the E47 mRNA and found that tristetraprolin (TTP), a physiological regulator of mRNA expression and stability, is involved in the degradation of the E47 mRNA. Although many studies have characterized TTP expression and function in macrophages, monocytes, mast cells, and T cells, little is known about the expression and function of TTP in primary B cells. We show herein that TTP mRNA and protein expression are induced by LPS in B cells from young and old mice, the levels of TTP in old B cells always being higher than those in young B cells. Although TTP mRNA is degraded at a significantly higher rate in old B cells, TTP mRNA expression is higher in old than in young, likely due to its increased transcription. Like in macrophages, TTP protein expression and function in B cells are dependent upon p38 MAPK. We found that there is less phospho-TTP (inactive form), as well as phospho-p38, in old than in young splenic-activated B cells. This is the first report showing that TTP is involved in the degradation of the E47 mRNA and is up-regulated in old B cells.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33101, USA
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45
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Yarovinsky TO, Butler NS, Monick MM, Hunninghake GW. Early exposure to IL-4 stabilizes IL-4 mRNA in CD4+ T cells via RNA-binding protein HuR. THE JOURNAL OF IMMUNOLOGY 2006; 177:4426-35. [PMID: 16982877 DOI: 10.4049/jimmunol.177.7.4426] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The mechanisms regulating IL-4 mRNA stability in differentiated T cells are not known. We found that early exposure of CD4+ T cells to endogenous IL-4 increased IL-4 mRNA stability. This effect of IL-4 was mediated by the RNA-binding protein HuR. IL-4 mRNA interacted with HuR and the dominant binding site was shown within the coding region of IL-4 mRNA. Exposure of CD4+ T cells to IL-4 had no effects on HuR expression or subcellular localization, but triggered HuR binding to IL-4 mRNA. Thus, IL-4 plays a positive role in maintaining IL-4 mRNA stability in CD4+ T cells via a HuR-mediated mechanism.
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Affiliation(s)
- Timur O Yarovinsky
- Roy J. and Lucille A. Carver College of Medicine, University of Iowa and Veterans Administration Medical Center, Iowa City, IA 52242, USA.
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46
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Barnstein BO, Li G, Wang Z, Kennedy S, Chalfant C, Nakajima H, Bunting KD, Ryan JJ. Stat5 expression is required for IgE-mediated mast cell function. THE JOURNAL OF IMMUNOLOGY 2006; 177:3421-6. [PMID: 16920984 DOI: 10.4049/jimmunol.177.5.3421] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The mast cell (MC) inflammatory response is now linked not only to atopy, but also to arthritis, multiple sclerosis, heart disease, and resistance to bacterial infection. In the current study, we demonstrate that the signal transducer and activator of transcription 5 (Stat5) is rapidly activated by IgE cross-linkage, and that its expression is critical to the MC response. Stat5-deficient (Stat5KO) MC demonstrated a significant decrease in IgE-mediated degranulation, leukotriene B4 production, cytokine secretion, and survival signals. The defect in cytokine production may be caused by decreased cytokine mRNA stability. Stat5KO MC-induced cytokine mRNAs normally following IgE cross-linkage, but these mRNAs were not sustained over time and were degraded at twice the rate observed in WT cells. Interestingly, the RNA destabilizing protein tristetraprolin was induced following IgE cross-linkage in Stat5KO but not wild-type cells. Moreover, reducing tristetraprolin expression via short hairpin RNA transfection significantly increased IL-13 production in Stat5KO MC. Our work demonstrates that Stat5 is a critical factor in IgE-induced MC activation, acting in part via posttranscriptional control of cytokine mRNA stability. These data have a direct impact on MC-associated inflammatory and autoimmune diseases.
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Affiliation(s)
- Brian O Barnstein
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
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Smoak K, Cidlowski JA. Glucocorticoids regulate tristetraprolin synthesis and posttranscriptionally regulate tumor necrosis factor alpha inflammatory signaling. Mol Cell Biol 2006; 26:9126-35. [PMID: 16982682 PMCID: PMC1636823 DOI: 10.1128/mcb.00679-06] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Glucocorticoids are used to treat various inflammatory disorders, but the mechanisms underlying these actions are incompletely understood. The zinc finger protein tristetraprolin (TTP) destabilizes several proinflammatory cytokine mRNAs by binding to AU-rich elements within their 3' untranslated regions, targeting them for degradation. Here we report that glucocorticoids induce the synthesis of TTP mRNA and protein in A549 lung epithelial cells and in rat tissues. Dexamethasone treatment leads to a sustained induction of TTP mRNA expression that is abrogated by RU486. Glucocorticoid induction of TTP mRNA is also blocked by actinomycin D but not by cycloheximide, suggesting a transcriptional mechanism which has been confirmed by transcription run-on experiments. The most widely characterized TTP-regulated gene is the AU-rich tumor necrosis factor alpha (TNF-alpha) gene. Dexamethasone represses TNF-alpha mRNA in A549 cells and decreases luciferase expression of a TNF-alpha 3' untranslated region reporter plasmid in an orientation-dependent manner. Small interfering RNAs to TTP significantly prevent this effect, and a cell line stably expressing a short-hairpin RNA to TTP conclusively establishes that TTP is critical for dexamethasone inhibition of TNF-alpha mRNA expression. These studies provide the molecular evidence for glucocorticoid regulation of human TTP and reflect a novel inductive anti-inflammatory signaling pathway for glucocorticoids that acts via posttranscriptional mechanisms.
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Affiliation(s)
- Kathleen Smoak
- Department of Health and Human Services, Laboratory of Signal Transduction, National Institute of Environmental Health Services, National Institutes of Health, Building 101, Research Triangle Park, NC 27709, USA
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Sauer I, Schaljo B, Vogl C, Gattermeier I, Kolbe T, Müller M, Blackshear PJ, Kovarik P. Interferons limit inflammatory responses by induction of tristetraprolin. Blood 2006; 107:4790-7. [PMID: 16514065 PMCID: PMC3963709 DOI: 10.1182/blood-2005-07-3058] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Interferons (IFNs) are cytokines with pronounced proinflammatory properties. Here we provide evidence that IFNs also play a key role in decline of inflammation by inducing expression of tristetraprolin (Ttp). TTP is an RNA-binding protein that destabilizes several AU-rich element-containing mRNAs including TNFalpha. By promoting mRNA decay, TTP significantly contributes to cytokine homeostasis. Now we report that IFNs strongly stimulate expression of TTP if a costimulatory stress signal is provided. IFN-induced expression of Ttp depends on the IFN-activated transcription factor STAT1, and the costimulatory stress signal requires p38 MAPK. Within the Ttp promoter we have identified a functional gamma interferon-activated sequence that recruits STAT1. Consistently, STAT1 is required for full expression of Ttp in response to LPS that stimulates both p38 MAPK and, indirectly, interferon signaling. We demonstrate that in macrophages IFN-induced TTP protein limits LPS-stimulated expression of several proinflammatory genes, such as TNFalpha, IL-6, Ccl2, and Ccl3. Thus, our findings establish a link between interferon responses and TTP-mediated mRNA decay during inflammation, and propose a novel immunomodulatory role of IFNs.
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Affiliation(s)
- Ines Sauer
- Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A-1030 Vienna, Austria
| | - Barbara Schaljo
- Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A-1030 Vienna, Austria
| | - Claus Vogl
- Institute of Animal Breeding and Genetics, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria
| | - Irene Gattermeier
- Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A-1030 Vienna, Austria
| | - Thomas Kolbe
- Austrian Center of Biomodelling and Transgenetics, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria
- Department of Agrobiotechnology, IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna
| | - Mathias Müller
- Austrian Center of Biomodelling and Transgenetics, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria
- Institute of Animal Breeding and Genetics, Vienna University of Veterinary Medicine, A-1210 Vienna, Austria
- Department of Agrobiotechnology, IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna
| | - Perry J. Blackshear
- Laboratory of Neurobiology, National Institute of Environmental Health Science, Research Triangle Park, North Carolina 27709, USA
| | - Pavel Kovarik
- Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, A-1030 Vienna, Austria
- Corresponding author: Pavel Kovarik, Max F. Perutz Laboratories, Department of Microbiology and Immunobiology, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria. Tel.: +43 1 4277 54608; Fax: +43 1 4277 9546;
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Matsui S, Sonoda Y, Sekiya T, Aizu-Yokota E, Kasahara T. Glycyrrhizin derivative inhibits eotaxin 1 production via STAT6 in human lung fibroblasts. Int Immunopharmacol 2006; 6:369-75. [PMID: 16428072 DOI: 10.1016/j.intimp.2005.08.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 08/24/2005] [Accepted: 08/31/2005] [Indexed: 11/16/2022]
Abstract
We recently demonstrated that glycyrrhizin (GL) and its derivatives down-regulate TNFalpha- and IL-4-induced eotaxin 1 production by the human fetal lung fibroblast line HFL-1 at protein or mRNA levels. In particular, the GL derivative hetero-30-OH-GL (3beta-[(2-O-beta-D-glucopyranuronosyl-beta-D-glucopyranuronosyl)oxy]-olean-11,13(18)-dien-30-ol) showed marked inhibition of eotaxin 1 production with less cytotoxicity than 18beta-GL. To identify the molecular mechanism of this effect, we focused on the inhibition of the transcriptional factors NF-kappaB and signal transducer and activator of transcription 6 (STAT6), which regulate eotaxin 1 gene activation. STAT6 phosphorylation and translocation of phospho-STAT6 from cytosol to nuclei were slightly inhibited by 18beta-GL and significantly inhibited by hetero-30-OH-GL. While IkappaBalpha degradation and translocation of NF-kappaB p65 to nuclei were not significantly affected by either compound, the stability of eotaxin-1 mRNA was decreased with hetero-30-OH-GL. In addition, eotaxin 1 promoter activity was markedly inhibited by hetero-30-OH-GL. Electrophoretic mobility shift assay (EMSA) confirmed these results. Thus, hetero-30-OH-GL significantly inhibited eotaxin 1 expression by the selective inhibition of IL-4 signal transduction as well as by enhanced mRNA degradation.
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Affiliation(s)
- Sachiko Matsui
- International Department, Minophagen Pharmaceutical Co., Ltd., Japan
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50
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Takatori H, Nakajima H, Kagami SI, Hirose K, Suto A, Suzuki K, Kubo M, Yoshimura A, Saito Y, Iwamoto I. Stat5a Inhibits IL-12-Induced Th1 Cell Differentiation through the Induction of Suppressor of Cytokine Signaling 3 Expression. THE JOURNAL OF IMMUNOLOGY 2005; 174:4105-12. [PMID: 15778369 DOI: 10.4049/jimmunol.174.7.4105] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In previous studies, we have shown that Th2 cell differentiation is diminished but Th1 cell differentiation is increased in Stat5a-deficient (Stat5a(-/-)) CD4(+) T cells. In the present study, we clarified the molecular mechanisms of Stat5a-mediated Th cell differentiation. We found that enhanced Th1 cell differentiation and the resultant IFN-gamma production played a dominant inhibitory role in the down-regulation of IL-4-induced Th2 cell differentiation of Stat5a(-/-) CD4(+) T cells. We also found that IL-12-induced Stat4 phosphorylation and Th1 cell differentiation were augmented in Stat5a(-/-) CD4(+) T cells. Importantly, the expression of suppressor of cytokine signaling (SOCS)3, a potent inhibitor of IL-12-induced Stat4 activation, was decreased in Stat5a(-/-) CD4(+) T cells. Moreover, a reporter assay showed that a constitutively active form of Stat5a but not Stat6 activated the SOCS3 promoter. Furthermore, chromatin immunoprecipitation assays revealed that Stat5a binds to the SOCS3 promoter in CD4(+) T cells. Finally, the retrovirus-mediated expression of SOCS3 restored the impaired Th cell differentiation of Stat5a(-/-) CD4(+) T cells. These results suggest that Stat5a forces the Th1/Th2 balance toward a Th2-type by preventing IL-12-induced Th1 cell differentiation through the induction of SOCS3.
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Affiliation(s)
- Hiroaki Takatori
- Department of Allergy and Clinical Immunology, Chiba University School of Medicine, Chiba City, Japan
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