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Iulini M, Maddalon A, Galbiati V, Corsini E. The Modified THP-1 Activation Assay for the In Vitro Identification of Drug-Inducing Systemic Hypersensitivity. FRONTIERS IN TOXICOLOGY 2022; 4:814050. [PMID: 35295210 PMCID: PMC8915845 DOI: 10.3389/ftox.2022.814050] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/31/2022] [Indexed: 12/23/2022] Open
Abstract
The development of new low molecular weight drugs has many chances of failure and is an expensive process. Currently, there are no screening methods and/or models to assess the hazard of hypersensitivity reactions to drugs (DHRs) in the preclinical phase. DHRs represent 6–15% of adverse drug reactions. Although rare, DHRs represent a serious health problem for predisposed individuals, resulting, in some cases, in life-threatening pathologies. To date, there are no in vitro or in vivo sensitive models able to predict the sensitizing potential of drugs in the preclinical tests, and these reactions are highlighted only after the drug has been placed on the market, affecting both population and public health. This article describes a novel approach methodology for the study of the sensitizing potential of drugs based on the use of the human promyelocytic cell line THP-1 as a surrogate for dendritic cells. The method is based on the upregulation of specific surface markers (CD86 and CD54) and on the production of IL-8. In our experience, the THP-1 activation assay allowed the correct identification of drugs known to induce systemic hypersensitivity in humans, including the one associated with specific HLAs. This method may help to discover possible systemic hypersensitivity reactions early in the preclinical phase of drug development.
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Galbiati V, Maddalon A, Iulini M, Marinovich M, Corsini E. Human keratinocytes and monocytes co-culture cell system: An important contribution for the study of moderate and weak sensitizers. Toxicol In Vitro 2020; 68:104929. [DOI: 10.1016/j.tiv.2020.104929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/10/2020] [Accepted: 06/30/2020] [Indexed: 12/17/2022]
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Galbiati V, Marinovich M, Corsini E. Mechanistic understanding of dendritic cell activation in skin sensitization: additional evidences to support potency classification. Toxicol Lett 2020; 322:50-57. [DOI: 10.1016/j.toxlet.2020.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 01/23/2023]
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Nader CP, Cidem A, Verrills NM, Ammit AJ. Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer. Respir Res 2019; 20:222. [PMID: 31623614 PMCID: PMC6798356 DOI: 10.1186/s12931-019-1192-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023] Open
Abstract
Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.
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Affiliation(s)
- Cassandra P Nader
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Aylin Cidem
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, 2308, Australia
- Priority Research Centre for Cancer Research, Innovation & Translation, Faculty of Health & Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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BAG3 regulates stability of IL-8 mRNA via interplay between HuR and miR-4312 in PDACs. Cell Death Dis 2018; 9:863. [PMID: 30154469 PMCID: PMC6113235 DOI: 10.1038/s41419-018-0874-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 12/13/2022]
Abstract
Bcl-2 associated athanogene 3 (BAG3) is highly expressed in pancreatic ductal adenocarcinoma (PDAC), and its high expression appears to be a poor prognostic factor for patients with PDAC. In this study, we show that BAG3 knockdown significantly decreases migration and invasion of PDACs via reduction of interleukine-8 (IL-8) production. BAG3 knockdown regulates IL-8 expression at the posttranscriptional levels via interplay between recruitment of RNA-binding protein HuR and miR-4312. HuR binds to the cis-elements located in the 3'-untranslational region (UTR) of the IL-8 transcript to stabilize it, whereas miR-4312-containing miRNA-induced silencing complex (miRISC) is recruited to the adjacent seed element to destabilize it. The binding of HuR prevents the recruitment of Argonaute (Ago2), overriding miR-4312-mediated translation inhibition of IL-8. BAG3 knockdown decreases cytoplasmic distribution of HuR via increasing its phosphorylation at Ser202, therefore compromising its recruitment while promoting recruitment of miR-4312 containing miRISC to IL-8 transcript. Furthermore, our data indicate that only phosphorylated Ago2 at Ser387 interacts with IL-8 transcript. BAG3 knockdown increases phosphorylation of Ago2 at Ser387, thereby further promoting loading of miR-4312 containing miRISC to IL-8 transcript. Taken together, we propose that BAG3 promotes invasion by stabilizing IL-8 transcript via HuR recruitment, and subsequently suppressing the loading of miR-4312 containing miRISC in PDACs. Our results reveal a novel pathway linking BAG3 expression to enhanced PDAC metastasis, thus making BAG3 a potential target for intervention in pancreatic cancer.
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Corsini E, Engin AB, Neagu M, Galbiati V, Nikitovic D, Tzanakakis G, Tsatsakis AM. Chemical-induced contact allergy: from mechanistic understanding to risk prevention. Arch Toxicol 2018; 92:3031-3050. [PMID: 30097700 DOI: 10.1007/s00204-018-2283-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022]
Abstract
Chemical allergens are small molecules able to form a sensitizing complex once they bound to proteins. One of the most frequent manifestations of chemical allergy is contact hypersensitivity, which can have serious impact on quality of life. Allergic contact dermatitis is a predominantly CD8 + T cell-mediated immune disease, resulting in erythema and eczema. Chemical allergy is of considerable importance to the toxicologist, who has the responsibility of identifying and characterizing the allergenic potential of chemicals, and estimating the risk they pose to human health. This review aimed at exploring the phenomena of chemical-induced contact allergy starting from a mechanistic understanding, immunoregulatory mechanisms, passing through the potency of contract allergen until the hazard identification, pointing out the in vitro models for assessing contact allergen-induced cell activation and the risk prevention.
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Affiliation(s)
- Emanuela Corsini
- Laboratory of Toxicology, Department of Environmental and Political Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133, Milan, Italy
| | - Ayşe Başak Engin
- Gazi Üniversitesi, Eczacılık Fakültesi, Toksikoloji, Hipodrom, 06330, Ankara, Turkey
| | - Monica Neagu
- Immunology Department, "Victor Babes" National Institute of Pathology, 99-101 Splaiul Independentei, 050096, Bucharest, Romania
| | - Valentina Galbiati
- Laboratory of Toxicology, Department of Environmental and Political Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133, Milan, Italy.
| | - Dragana Nikitovic
- Department of Histology-Embryology, School of Medicine, University of Crete, Heraklion, Greece
| | - George Tzanakakis
- Department of Histology-Embryology, School of Medicine, University of Crete, Heraklion, Greece
| | - Aristidis M Tsatsakis
- Department of Forensic Sciences and Toxicology, University of Crete, Heraklion, Greece
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Corsini E, Galbiati V, Papale A, Kummer E, Pinto A, Guaita A, Racchi M. The role of HSP27 in RACK1-mediated PKC activation in THP-1 cells. Immunol Res 2017; 64:940-50. [PMID: 27178349 DOI: 10.1007/s12026-016-8802-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Receptor for Activated C Kinase 1 (RACK1) pseudosubstrate is a commercially available peptide that directly activates protein kinase C-β (PKCβ). We have recently shown that RACK1 pseudosubstrate, alone or in combination with classical immune activators, results in increased cytokine production and CD86 upregulation in primary leukocytes. Furthermore, we demonstrated a role of PKCβ and RACK1 in chemical allergen-induced CD86 expression and IL-8 production in both THP-1 cells and primary human dendritic cells. Aim of this study was to shed light on the mechanisms underlying RACK1 pseudosubstrate-induced immune activation and to compare it to lipopolysaccharide (LPS). The human promyelocytic cell line THP-1 was used throughout the study. RACK1 pseudosubstrate induced rapid (5 min) and dose-related PKCβ activation as assessed by its membrane translocation. Among the proteins phosphorylated, we identified Hsp27. Both RACK1 pseudosubstrate and LPS induce its phosphorylation and release in culture medium. The release of Hsp27 induced by RACK1 pseudosubstrate was also confirmed in peripheral blood mononuclear cells. To evaluate the role of Hsp27 in RACK1 pseudosubstrate or LPS-induced cell activation, we conducted Hsp27 silencing and neutralization experiments. Both strategies confirmed the central role of Hsp27 in RACK1 pseudosubstrate or LPS-induced cell activation, as assessed by IL-8 production and upregulation of CD86.
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Affiliation(s)
- Emanuela Corsini
- Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy
| | - Valentina Galbiati
- Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy
| | - Angela Papale
- Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy
| | - Elena Kummer
- Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy
| | - Antonella Pinto
- Department of Drug Sciences - Pharmacology, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy
| | | | - Marco Racchi
- Department of Drug Sciences - Pharmacology, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy.
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Komnenov D, Scipione C, Bazzi Z, Garabon J, Koschinsky M, Boffa M. Pro-inflammatory cytokines reduce human TAFI expression via tristetraprolin-mediated mRNA destabilisation and decreased binding of HuR. Thromb Haemost 2017; 114:337-49. [DOI: 10.1160/th14-08-0653] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 03/12/2015] [Indexed: 01/26/2023]
Abstract
SummaryThrombin activatable fibrinolysis inhibitor (TAFI) is the zymogen form of a basic carboxypeptidase (TAFIa) with both anti-fibrinolytic and anti-inflammatory properties. The role of TAFI in inflammatory disease is multifaceted and involves modulation both of specific inflammatory mediators as well as of the behaviour of inflammatory cells. Moreover, as suggested by in vitro studies, inflammatory mediators are capable of regulating the expression of CPB2, the gene encoding TAFI. In this study we addressed the hypothesis that decreased TAFI levels observed in inflammation are due to post-transcriptional mechanisms. Treatment of human HepG2 cells with pro-inflammatory cytokines TNFα, IL-6 in combination with IL-1β, or with bacterial lipopolysaccharide (LPS) decreased TAFI protein levels by approximately two-fold over 24 to 48 hours of treatment. Conversely, treatment of HepG2 cells with the anti-inflammatory cytokine IL-10 increased TAFI protein levels by two-fold at both time points. We found that the mechanistic basis for this modulation of TAFI levels involves binding of tristetraprolin (TTP) to the CPB2 3′-UTR, which mediates CPB2 mRNA destabilisation. In this report we also identified that HuR, another ARE-binding protein but one that stabilises transcripts, is capable of binding the CBP2 3’UTR. We found that pro-inflammatory mediators reduce the occupancy of HuR on the CPB2 3’-UTR and that the mutation of the TTP binding site in this context abolishes this effect, although TTP and HuR appear to contact discrete binding sites. Interestingly, all of the mediators tested appear to increase TAFI protein expression in THP-1 macrophages, likewise through effects on CPB2 mRNA stability.
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HCV-Negative Mixed Cryoglobulinemic Glomerulonephritis and Solid Malignancy: A Case Report and Review of the Literature. Nephrourol Mon 2017. [DOI: 10.5812/numonthly.58142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Galbiati V, Papale A, Kummer E, Corsini E. In vitro Models to Evaluate Drug-Induced Hypersensitivity: Potential Test Based on Activation of Dendritic Cells. Front Pharmacol 2016; 7:204. [PMID: 27462271 PMCID: PMC4940371 DOI: 10.3389/fphar.2016.00204] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/27/2016] [Indexed: 01/11/2023] Open
Abstract
Hypersensitivity drug reactions (HDRs) are the adverse effect of pharmaceuticals that clinically resemble allergy. HDRs account for approximately 1/6 of drug-induced adverse effects, and include immune-mediated ("allergic") and non-immune-mediated ("pseudo allergic") reactions. In recent years, the severe and unpredicted drug adverse events clearly indicate that the immune system can be a critical target of drugs. Enhanced prediction in preclinical safety evaluation is, therefore, crucial. Nowadays, there are no validated in vitro or in vivo methods to screen the sensitizing potential of drugs in the pre-clinical phase. The problem of non-predictability of immunologically-based hypersensitivity reactions is related to the lack of appropriate experimental models rather than to the lack of -understanding of the adverse phenomenon. We recently established experimental conditions and markers to correctly identify drug associated with in vivo hypersensitivity reactions using THP-1 cells and IL-8 production, CD86 and CD54 expression. The proposed in vitro method benefits from a rationalistic approach with the idea that allergenic drugs share with chemical allergens common mechanisms of cell activation. This assay can be easily incorporated into drug development for hazard identification of drugs, which may have the potential to cause in vivo hypersensitivity reactions. The purpose of this review is to assess the state of the art of in vitro models to assess the allergenic potential of drugs based on the activation of dendritic cells.
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Affiliation(s)
- Valentina Galbiati
- Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano Milan, Italy
| | - Angela Papale
- Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano Milan, Italy
| | - Elena Kummer
- Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano Milan, Italy
| | - Emanuela Corsini
- Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano Milan, Italy
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Lourenço A, Galbiati V, Corti D, Papale A, Martino-Andrade A, Corsini E. The plasticizer dibutyl phthalate (DBP) potentiates chemical allergen-induced THP-1 activation. Toxicol In Vitro 2015; 29:2001-8. [DOI: 10.1016/j.tiv.2015.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
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Optimization of the THP-1 activation assay to detect pharmaceuticals with potential to cause immune mediated drug reactions. Toxicol In Vitro 2015; 29:1339-49. [DOI: 10.1016/j.tiv.2015.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/19/2015] [Accepted: 04/20/2015] [Indexed: 11/17/2022]
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Griseri P, Pagès G. Control of pro-angiogenic cytokine mRNA half-life in cancer: the role of AU-rich elements and associated proteins. J Interferon Cytokine Res 2015; 34:242-54. [PMID: 24697202 DOI: 10.1089/jir.2013.0140] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Control of mRNA half-life plays a central role in normal development and disease. Several pathological conditions, such as inflammation and cancer, tightly correlate with deregulation in mRNA stability of pro-inflammatory genes. Among these, pro-angiogenesis cytokines, which play a crucial role in the formation of new blood vessels, normally show rapid mRNA decay patterns. The mRNA half-life of these genes appears to be regulated by mRNA-binding proteins that interact with AU-rich elements (AREs) in the 3'-untranslated region of mRNAs. Some of these RNA-binding proteins, such as tristetraprolin (TTP), ARE RNA-binding protein 1, and KH-type splicing regulatory protein, normally promote mRNA degradation. Conversely, other proteins, such as embryonic lethal abnormal vision-like protein 1 (HuR) and polyadenylate-binding protein-interacting protein 2, act as antagonists, stabilizing the mRNA. The steady state levels of mRNA-binding proteins and their relative ratio is often perturbed in human cancers and associated with invasion and aggressiveness. Compelling evidence also suggests that underexpression of TTP and overexpression of HuR may be a useful prognostic and predictive marker in breast, colon, prostate, and brain cancers, indicating a potential therapeutic approach for these tumors. In this review, we summarize the main mechanisms involved in the regulation of mRNA decay of pro-angiogenesis cytokines in different cancers and discuss the interactions between the AU-rich-binding proteins and their mRNA targets.
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Affiliation(s)
- Paola Griseri
- 1 U.O.C Medical Genetics, Institute Giannina Gaslini , Genoa, Italy
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Prabhala P, Ammit AJ. Tristetraprolin and its role in regulation of airway inflammation. Mol Pharmacol 2014; 87:629-38. [PMID: 25429052 DOI: 10.1124/mol.114.095984] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Chronic inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), are clinically and socioeconomically important diseases globally. Currently the mainstay of anti-inflammatory therapy in respiratory diseases is corticosteroids. Although corticosteroids have proven clinical efficacy in asthma, many asthmatic inflammatory conditions (e.g., infection, exacerbation, and severe asthma) are not responsive to corticosteroids. Moreover, despite an understanding that COPD progression is driven by inflammation, we currently do not have effective anti-inflammatory strategies to combat this disease. Hence, alternative anti-inflammatory strategies are required. p38 mitogen-activated protein kinase (MAPK) has emerged as an important signaling molecule driving airway inflammation, and pharmacological inhibitors against p38 MAPK may provide potential therapies for chronic respiratory disease. In this review, we discuss some of the recent in vitro and in vivo studies targeting p38 MAPK, but suggest that p38 MAPK inhibitors may prove less effective than originally considered because they may block anti-inflammatory molecules along with proinflammatory responses. We propose that an alternative strategy may be to target an anti-inflammatory molecule farther downstream of p38 MAPK, i.e., tristetraprolin (TTP). TTP is an mRNA-destabilizing, RNA-binding protein that enhances the decay of mRNAs, including those encoding proteins implicated in chronic respiratory diseases. We suggest that understanding the molecular mechanism of TTP expression and its temporal regulation will guide future development of novel anti-inflammatory pharmacotherapeutic approaches to combat respiratory disease.
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Affiliation(s)
- Pavan Prabhala
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
| | - Alaina J Ammit
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
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Corsini E, Galbiati V, Esser PR, Pinto A, Racchi M, Marinovich M, Martin SF, Galli CL. Role of PKC-β in chemical allergen-induced CD86 expression and IL-8 release in THP-1 cells. Arch Toxicol 2013; 88:415-24. [PMID: 24136171 DOI: 10.1007/s00204-013-1144-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022]
Abstract
We previously demonstrated an age-related decrease in receptor for activated C-kinase (RACK-1) expression and functional deficit in Langerhans cells' responsiveness. This defect specifically involves the translocation of protein kinase C (PKC)-β. The purpose of this study was to investigate the role of RACK-1 and PKC-β in chemical allergen-induced CD86 expression and IL-8 release in the human promyelocytic cell line THP-1 and primary human dendritic cells (DC). Dinitrochlorobenzene, p-phenylenediamine and diethyl maleate were used as contact allergens. The selective cell-permeable inhibitor of PKC-β and the broad PKC inhibitor GF109203X completely prevented chemical allergen- or lipopolysaccharide (LPS)-induced CD86 expression and significantly modulated IL-8 release (50 % reduction). The selective cell-permeable inhibitor of PKC-ε (also known to bind to RACK-1) failed to modulate allergen- or LPS-induced CD86 expression or allergen-induced IL-8 release, while modulating LPS-induced IL-8 release. The use of a RACK-1 pseudosubstrate, which directly activates PKC-β, resulted in dose-related increase in CD86 expression and IL-8 release. Similar results were obtained with human DC, confirming the relevance of results obtained in THP-1 cells. Overall, our findings demonstrate the role of PKC-β and RACK-1 in allergen-induced CD86 expression and IL-8 production, supporting a central role of PKC-β in the initiation of chemical allergen-induced DC activation.
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Affiliation(s)
- Emanuela Corsini
- Laboratory of Toxicology, Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Via G. Balzaretti 9, 20133, Milan, Italy,
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Brooks SA, Blackshear PJ. Tristetraprolin (TTP): interactions with mRNA and proteins, and current thoughts on mechanisms of action. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1829:666-79. [PMID: 23428348 PMCID: PMC3752887 DOI: 10.1016/j.bbagrm.2013.02.003] [Citation(s) in RCA: 296] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 01/25/2013] [Accepted: 02/04/2013] [Indexed: 12/14/2022]
Abstract
Changes in mRNA stability and translation are critical control points in the regulation of gene expression, particularly genes encoding growth factors, inflammatory mediators, and proto-oncogenes. Adenosine and uridine (AU)-rich elements (ARE), often located in the 3' untranslated regions (3'UTR) of mRNAs, are known to target transcripts for rapid decay. They are also involved in the regulation of mRNA stability and translation in response to extracellular cues. This review focuses on one of the best characterized ARE binding proteins, tristetraprolin (TTP), the founding member of a small family of CCCH tandem zinc finger proteins. In this survey, we have reviewed the current status of TTP interactions with mRNA and proteins, and discussed current thinking about TTP's mechanism of action to promote mRNA decay. We also review the proposed regulation of TTP's functions by phosphorylation. Finally, we have discussed emerging evidence for TTP operating as a translational regulator. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Affiliation(s)
- Seth A. Brooks
- Veterans Affairs Medical Center, White River Junction, Vermont, USA
- Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Perry J. Blackshear
- The Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
- Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina USA
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