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Abstract
Alzheimer's disease (AD) is a debilitating age-related neurodegenerative condition. Unbiased genetic studies have implicated a central role for microglia, the resident innate immune cells of the central nervous system, in AD pathogenesis. On-going efforts are clarifying the biology underlying these associations and the microglial pathways that are dysfunctional in AD. Several genetic risk factors converge to decrease the function of activating microglial receptors and increase the function of inhibitory receptors, resulting in a seemingly dampened microglial phenotype in AD. Moreover, many of these microglial proteins that are genetically associated with AD appear to interact and share pathways or regulatory mechanisms, presenting several points of convergence that may be strategic targets for therapeutic intervention. Here, we review some of these studies and their implications for microglial participation in AD pathogenesis.
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McDonald CR, Leligdowicz A, Conroy AL, Weckman AM, Richard-Greenblatt M, Ngai M, Erice C, Zhong K, Namasopo S, Opoka RO, Hawkes MT, Kain KC. Immune and endothelial activation markers and risk stratification of childhood pneumonia in Uganda: A secondary analysis of a prospective cohort study. PLoS Med 2022; 19:e1004057. [PMID: 35830474 PMCID: PMC9328519 DOI: 10.1371/journal.pmed.1004057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 07/27/2022] [Accepted: 06/23/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite the global burden of pneumonia, reliable triage tools to identify children in low-resource settings at risk of severe and fatal respiratory tract infection are lacking. This study assessed the ability of circulating host markers of immune and endothelial activation quantified at presentation, relative to currently used clinical measures of disease severity, to identify children with pneumonia who are at risk of death. METHODS AND FINDINGS We conducted a secondary analysis of a prospective cohort study of children aged 2 to 59 months presenting to the Jinja Regional Hospital in Jinja, Uganda between February 2012 and August 2013, who met the Integrated Management of Childhood Illness (IMCI) diagnostic criteria for pneumonia. Circulating plasma markers of immune (IL-6, IL-8, CXCL-10/IP-10, CHI3L1, sTNFR1, and sTREM-1) and endothelial (sVCAM-1, sICAM-1, Angpt-1, Angpt-2, and sFlt-1) activation measured at hospital presentation were compared to lactate, respiratory rate, oxygen saturation, procalcitonin (PCT), and C-reactive protein (CRP) with a primary outcome of predicting 48-hour mortality. Of 805 children with IMCI pneumonia, 616 had severe pneumonia. Compared to 10 other immune and endothelial activation markers, sTREM-1 levels at presentation had the best predictive accuracy in identifying 48-hour mortality for children with pneumonia (AUROC 0.885, 95% CI 0.841 to 0.928; p = 0.03 to p < 0.001) and severe pneumonia (AUROC 0.870, 95% CI 0.824 to 0.916; p = 0.04 to p < 0.001). sTREM-1 was more strongly associated with 48-hour mortality than lactate (AUROC 0.745, 95% CI 0.664 to 0.826; p < 0.001), respiratory rate (AUROC 0.615, 95% CI 0.528 to 0.702; p < 0.001), oxygen saturation (AUROC 0.685, 95% CI 0.594 to 0.776; p = 0.002), PCT (AUROC 0.650, 95% CI 0.566 to 0.734; p < 0.001), and CRP (AUROC 0.562, 95% CI 0.472 to 0.653; p < 0.001) in cases of pneumonia and severe pneumonia. The main limitation of this study was the unavailability of radiographic imaging. CONCLUSIONS In this cohort of Ugandan children, sTREM-1 measured at hospital presentation was a significantly better indicator of 48-hour mortality risk than other common approaches to risk stratify children with pneumonia. Measuring sTREM-1 at clinical presentation may improve the early triage, management, and outcome of children with pneumonia at risk of death. TRIAL REGISTRATION The trial was registered at clinicaltrial.gov (NCT04726826).
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Affiliation(s)
- Chloe R. McDonald
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Aleksandra Leligdowicz
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
- Department of Medicine, Division of Critical Care Medicine, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Andrea L. Conroy
- Department of Pediatrics, Indiana University, School of Medicine, Indianapolis, Indiana, United States of America
| | - Andrea M. Weckman
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Melissa Richard-Greenblatt
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- Public Health Ontario Laboratory, Toronto, Canada
| | - Michelle Ngai
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Clara Erice
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Kathleen Zhong
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Sophie Namasopo
- Department of Paediatrics, Kabale Regional Referral Hospital, Kabale, Uganda
| | - Robert O. Opoka
- Department of Paediatrics and Child Health, Mulago Hospital and Makerere University, Kawempe, Kampala, Uganda
| | - Michael T. Hawkes
- Division of Pediatric Infectious Diseases, University of Alberta, Edmonton, Canada
| | - Kevin C. Kain
- SAR Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Canada
- * E-mail:
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Richard-Greenblatt M, Boillat-Blanco N, Zhong K, Mbarack Z, Samaka J, Mlaganile T, Kazimoto T, D'acremont V, Kain KC. Prognostic Accuracy of Soluble Triggering Receptor Expressed on Myeloid Cells (sTREM-1)-based Algorithms in Febrile Adults Presenting to Tanzanian Outpatient Clinics. Clin Infect Dis 2021; 70:1304-1312. [PMID: 31102510 DOI: 10.1093/cid/ciz419] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/17/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The inability to identify individuals with acute fever at risk of death is a barrier to effective triage and management of severe infections, especially in low-resource settings. Since endothelial and immune activation contribute to the pathogenesis of various distinct life-threatening infections, we hypothesized that measuring mediators of these pathways at clinical presentation would identify febrile adults at risk of death. METHODS Plasma concentrations of markers of endothelial (angiopoetin-1/2, soluble fms-like tyrosine kinase-1, soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1) and immune (soluble triggering receptor expressed on myeloid cells [sTREM-1], interleukin-6, interleukin-8, chitinase-3-like protein-1, soluble tumor necrosis factor receptor-1, procalcitonin [PCT], C-reactive protein [CRP]) activation pathways were determined in consecutive adults with acute fever (≥38°C) at presentation to outpatient clinics in Dar es Salaam, Tanzania. We evaluated the accuracy of these mediators in predicting all-cause mortality and examined whether markers could improve the prognostic accuracy of clinical scoring systems, including the quick sequential organ failure assessment (qSOFA) and Glasgow coma scale (GCS). RESULTS Of 507 febrile adults, 32 died (6.3%) within 28 days of presentation. We found that sTREM-1 was the best prognostic marker for 28-day mortality (area under the receiver operating characteristic [AUROC] 0.87, 95% confidence interval [CI] 0.81-0.92) and was significantly better than CRP (P < .0001) and PCT (P = .0001). The prognostic accuracy of qSOFA and the GCS were significantly enhanced when sTREM-1 was added (0.80 [95% CI 0.76-0.83] to 0.91 [95% CI 0.88-0.94; P < .05] and 0.72 [95% CI 0.63-0.80] to 0.94 [95% CI 0.91-0.97; P < .05], respectively). CONCLUSIONS Measuring sTREM-1 at clinical presentation can identify febrile individuals at risk of all-cause febrile mortality. Adding severity markers such as sTREM-1 to simple clinical scores could improve the recognition and triage of patients with life-threatening infections in resource-limited settings.
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Affiliation(s)
| | | | - Kathleen Zhong
- Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Canada
| | - Zainab Mbarack
- Mwananyamala Hospita, Dar es Salaam, United Republic of Tanzanial
| | - Josephine Samaka
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Tarsis Mlaganile
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Thekla Kazimoto
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Valerie D'acremont
- Swiss Tropical and Public Health Institute, Basel.,University Centre of General Medicine and Public Health, Lausanne, Switzerland
| | - Kevin C Kain
- Tropical Disease Unit, Department of Medicine, University of Toronto, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Canada
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Pan P, Liu X, Wu L, Li X, Wang K, Wang X, Zhou X, Long Y, Liu D, Xie L, Su L. TREM-1 promoted apoptosis and inhibited autophagy in LPS-treated HK-2 cells through the NF-κB pathway. Int J Med Sci 2021; 18:8-17. [PMID: 33390769 PMCID: PMC7738954 DOI: 10.7150/ijms.50893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/22/2020] [Indexed: 11/16/2022] Open
Abstract
Triggering receptor expressed by myeloid cells (TREM-1) is an amplifier of inflammatory responses triggered by bacterial or fungal infection. Soluble TREM-1 (sTREM-1) expression was found to be upregulated in sepsis-associated acute kidney injury (SA-AKI) and predicted to be a potential biomarker. However, the mechanism remains unclear. The human kidney-2 (HK-2) cell line was treated with lipopolysaccharide (LPS) and used to examine the potential roles of TREM-1 in apoptosis and autophagy. A cell viability assay was employed to assess the number of viable cells and as a measure of the proliferative index. The concentrations of sTREM-1, interleukin (IL)-1β, tumor necrosis factor-α (TNFα) and IL-6 in cell-free culture supernatants were measured by enzyme-linked immunosorbent assay (ELISA). Western blot analysis was performed to analyze apoptosis, autophagy and the relevant signaling pathways. The results suggested that TREM-1 overexpression after LPS treatment decreased proliferation and increased apoptosis. The concentrations of sTREM-1, IL-1β, TNFα and IL-6 in cell-free culture supernatants were increased in the TREM-1 overexpression group after LPS treatment. Expression of the antiapoptotic gene Bcl-2 was downregulated in the TREM-1 overexpression group, while that of the proapoptotic genes Bax, cleaved caspase-3 and cleaved caspase-9 was upregulated. Overexpression of TREM-1 downregulated expression of the autophagy genes Beclin-1, Atg-5 and LC3b and increased the gene expression of p62, which inhibits autophagy. Conversely, treatment with TREM-1-specific shRNA had the opposite effects. The nuclear factor-κB (NF-κB) signaling pathway (P-p65/p65 and P-IκBα/IκBα) in LPS-induced HK-2 cells was regulated by TREM-1. In summary, TREM-1 promoted apoptosis and inhibited autophagy in HK-2 cells in the context of LPS exposure potentially through the NF-κB pathway.
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Affiliation(s)
- Pan Pan
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, 17th Heishanhujia, Haidian District, Beijing 100091, China
| | - Xudong Liu
- Medical Science Research Center, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - LingLing Wu
- Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing 100853, China
| | - Xiaogang Li
- Medical Science Research Center, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Kaifei Wang
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, 17th Heishanhujia, Haidian District, Beijing 100091, China
| | - Xiaoting Wang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiang Zhou
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yun Long
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Dawei Liu
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Lixin Xie
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, 17th Heishanhujia, Haidian District, Beijing 100091, China
| | - Longxiang Su
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100730, China
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Jafarlou M, Shanehbandi D, Dehghan P, Mansoori B, Othman F, Baradaran B. Enhancement of chemosensitivity by simultaneously silencing of Mcl-1 and Survivin genes using small interfering RNA in human myelomonocytic leukaemia. Artif Cells Nanomed Biotechnol 2017; 46:1792-1798. [PMID: 29113504 DOI: 10.1080/21691401.2017.1392969] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Acute myeloid leukaemia (AML) is a genetically heterogeneous, severe and rapidly progressing disease triggered by blocking granulocyte or monocyte differentiation and maturation. Overexpression of myeloid cell leukaemia-1 (Mcl-1) and Survivin is associated with drug resistance, tumour progression and inhibition of apoptotic mechanisms in leukaemia and several cancers. In the present study, we examined the combined effect of etoposide and dual siRNA-mediated silencing of Mcl-1 and Survivin on U-937 AML cells. The AML cells were co-transfected with Mcl-1 and Survivin-specific siRNAs and genes silencing were confirmed by quantitative real-time PCR and Western blotting. Subsequently, MTT assay was used for the evaluation of cytotoxic effects by dual siRNA and etoposide on their own and in combination. For the studying of apoptosis, DNA-histone ELISA and annexin-V/FITC assays were performed. Co-transfection of Mcl-1 and Survivin siRNA significantly blocked their expression at the mRNA and protein levels, leading to the induction of apoptosis and strong inhibition of growth (p < .05). Besides, combined treatment of etoposide with Mcl-1 and Survivin siRNAs co-transfection leads to synergistically enhance etoposide-induced cytotoxic and apoptotic effects (p < .05). The results showed that Mcl-1 and Survivin play a major role in the U937 cells survival and their resistance relative to etoposide. Thus, Mcl-1 and Survivin can be considered as promising molecular targets for the treatment of AML. The combination treatment with etoposide, and siRNA-mediated silencing of corresponding genes may be a novel strategy in chemoresistance AML treatment.
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Affiliation(s)
- Mahdi Jafarlou
- a Immunology Research Center , Tabriz University of Medical Sciences , Tabriz , Iran.,b Department of Human Anatomy, Faculty of Medicine and Health Sciences, UPM , Selangor , Malaysia
| | - Dariush Shanehbandi
- a Immunology Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Parvin Dehghan
- c Nutrition Research Center, Tabriz University of Medical Sciences , Tabriz , Iran
| | - Behzad Mansoori
- a Immunology Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
| | - F Othman
- b Department of Human Anatomy, Faculty of Medicine and Health Sciences, UPM , Selangor , Malaysia
| | - Behzad Baradaran
- a Immunology Research Center , Tabriz University of Medical Sciences , Tabriz , Iran
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Joffre J, Potteaux S, Zeboudj L, Loyer X, Boufenzer A, Laurans L, Esposito B, Vandestienne M, de Jager SCA, Hénique C, Zlatanova I, Taleb S, Bruneval P, Tedgui A, Mallat Z, Gibot S, Ait-Oufella H. Genetic and Pharmacological Inhibition of TREM-1 Limits the Development of Experimental Atherosclerosis. J Am Coll Cardiol 2017; 68:2776-2793. [PMID: 28007141 DOI: 10.1016/j.jacc.2016.10.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 09/12/2016] [Accepted: 10/04/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Innate immune responses activated through myeloid cells contribute to the initiation, progression, and complications of atherosclerosis in experimental models. However, the critical upstream pathways that link innate immune activation to foam cell formation are still poorly identified. OBJECTIVES This study sought to investigate the hypothesis that activation of the triggering receptor expressed on myeloid cells (TREM-1) plays a determinant role in macrophage atherogenic responses. METHODS After genetically invalidating Trem-1 in chimeric Ldlr-/-Trem-1-/- mice and double knockout ApoE-/-Trem-1-/- mice, we pharmacologically inhibited Trem-1 using LR12 peptide. RESULTS Ldlr-/- mice reconstituted with bone marrow deficient for Trem-1 (Trem-1-/-) showed a strong reduction of atherosclerotic plaque size in both the aortic sinus and the thoracoabdominal aorta, and were less inflammatory compared to plaques of Trem-1+/+ chimeric mice. Genetic invalidation of Trem-1 led to alteration of monocyte recruitment into atherosclerotic lesions and inhibited toll-like receptor 4 (TLR 4)-initiated proinflammatory macrophage responses. We identified a critical role for Trem-1 in the upregulation of cluster of differentiation 36 (CD36), thereby promoting the formation of inflammatory foam cells. Genetic invalidation of Trem-1 in ApoE-/-/Trem-1-/- mice or pharmacological blockade of Trem-1 in ApoE-/- mice using LR-12 peptide also significantly reduced the development of atherosclerosis throughout the vascular tree, and lessened plaque inflammation. TREM-1 was expressed in human atherosclerotic lesions, mainly in lipid-rich areas with significantly higher levels of expression in atheromatous than in fibrous plaques. CONCLUSIONS We identified TREM-1 as a major upstream proatherogenic receptor. We propose that TREM-1 activation orchestrates monocyte/macrophage proinflammatory responses and foam cell formation through coordinated and combined activation of CD36 and TLR4. Blockade of TREM-1 signaling may constitute an attractive novel and double-hit approach for the treatment of atherosclerosis.
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Affiliation(s)
- Jeremie Joffre
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Stephane Potteaux
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Lynda Zeboudj
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Xavier Loyer
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | | | - Ludivine Laurans
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Bruno Esposito
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marie Vandestienne
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Saskia C A de Jager
- Laboratory for Experimental Cardiology, University Medical Center, Utrecht, the Netherlands
| | - Carole Hénique
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ivana Zlatanova
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Soraya Taleb
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Patrick Bruneval
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Department of Anatomopathology, Hôpital Européen Georges Pompidou, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Alain Tedgui
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ziad Mallat
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Department of Medicine, Division of Cardiovascular Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Sebastien Gibot
- INSERM Unité mixte de Recherche-S1116, Faculté de Médecine, Université de Lorraine, Medical Intensive Care Unit, Hôpital Central, Nancy, France
| | - Hafid Ait-Oufella
- INSERM U970, Paris Cardiovascular Research Center, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Medical Intensive Care Unit, Hôpital Saint-Antoine, Assistance Publique-Hopitaux de Paris, Université Pierre-et-Marie Curie, Paris, France.
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Chen C, Zhao D, Fang S, Chen Q, Cheng B, Fang X, Shu Q. TRIM22-Mediated Apoptosis is Associated with Bak Oligomerization in Monocytes. Sci Rep 2017; 7:39961. [PMID: 28079123 PMCID: PMC5228056 DOI: 10.1038/srep39961] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/28/2016] [Indexed: 11/09/2022] Open
Abstract
Monocyte apoptosis is a key mechanism that orchestrates host immune responses during sepsis. TRIM22 is constitutively expressed at high levels in monocytes and plays important roles in the antiviral response and inflammation. Overexpression of TRIM22 interferes with the clonogenic growth of monocytic cells, suggesting that TRIM22 may regulate monocyte survival. However, the effect of TRIM22 on monocyte apoptosis remains unknown. In the present report, lipopolysaccharides (LPS)-primed human peripheral blood monocytes expressing higher levels of TRIM22 were more sensitive to apoptosis. This phenomenon was also observed in TRIM22-overexpressing THP-1 monocytes and was associated with the activation of caspase-9 and caspase-3, as well as the increased expression and oligomerization of the pro-apoptotic protein Bak. Similar expression patterns of TRIM22 and Bak were also observed in LPS-primed, apoptotic human peripheral blood monocytes. In addition, the deletion of either the RING domain or the SPRY domain of TRIM22 significantly attenuated TRIM22-mediated monocyte apoptosis and decreased Bak expression and oligomerization. Furthermore, in monocytes from septic patients, TRIM22 levels were down-regulated and positively correlated with Bak levels. Taken together, these results indicate that TRIM22 plays a critical role in monocyte apoptosis by regulating Bak oligomerization and may have a potential function in the pathogenesis of sepsis.
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Affiliation(s)
- Chi Chen
- Department of Thoracic and Cardiovascular Surgery, Children's Hospital, School of Medicine, Zhejiang University, and Zhejiang Key Laboratory for Diagnosis and Therapy of Neonatal Diseases, Hangzhou 310052, China
| | - DongYan Zhao
- Department of Thoracic and Cardiovascular Surgery, Children's Hospital, School of Medicine, Zhejiang University, and Zhejiang Key Laboratory for Diagnosis and Therapy of Neonatal Diseases, Hangzhou 310052, China
| | - Shu Fang
- Department of Thoracic and Cardiovascular Surgery, Children's Hospital, School of Medicine, Zhejiang University, and Zhejiang Key Laboratory for Diagnosis and Therapy of Neonatal Diseases, Hangzhou 310052, China
| | - QiXing Chen
- Clinical Research Center, Children's Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - BaoLi Cheng
- Department of Anesthesiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - XiangMing Fang
- Department of Anesthesiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Qiang Shu
- Department of Thoracic and Cardiovascular Surgery, Children's Hospital, School of Medicine, Zhejiang University, and Zhejiang Key Laboratory for Diagnosis and Therapy of Neonatal Diseases, Hangzhou 310052, China
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Hu LT, Du ZD, Zhao GQ, Jiang N, Lin J, Wang Q, Xu Q, Cong L, Qiu S. Role of TREM-1 in response to Aspergillus fumigatus infection in corneal epithelial cells. Int Immunopharmacol 2014; 23:288-93. [DOI: 10.1016/j.intimp.2014.09.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/06/2014] [Accepted: 09/09/2014] [Indexed: 01/22/2023]
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Qian X, Numata T, Zhang K, Li C, Hou J, Mori Y, Fang X. Transient receptor potential melastatin 2 protects mice against polymicrobial sepsis by enhancing bacterial clearance. Anesthesiology 2014; 121:336-51. [PMID: 24781495 DOI: 10.1097/ALN.0000000000000275] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Recent studies suggest that the transient receptor potential melastatin 2 (TRPM2) channel plays an important role in inflammation and immune response. However, the role and mechanism of TRPM2 in polymicrobial sepsis remain unclear. METHODS The authors explored the effects of genetic disruption of TRPM2 on mortality (n = 15), bacterial clearance (n = 6), organ injury, and systemic inflammation during cecal ligation and puncture-induced sepsis. Electrophysiology, immunoblot, bacterial clearance experiment, and quantitative real-time polymerase chain reaction were used to explore the role and mechanism of TRPM2 in sepsis. RESULTS After cecal ligation and puncture, Trpm2-knockout mice had increased mortality compared with wild-type mice (73.3 vs. 40%, P = 0.0289). The increased mortality was associated with increased bacterial burden, organ injury, and systemic inflammation. TRPM2-mediated Ca influx plays an important role in lipopolysaccharide or cecal ligation and puncture-induced heme oxygenase-1 (HO-1) expression in macrophage. HO-1 up-regulation decreased bacterial burden both in wild-type bone marrow-derived macrophages and in cecal ligation and puncture-induced septic wild-type mice. Disruption of TRPM2 decreased HO-1 expression and increased bacterial burden in bone marrow-derived macrophages. Pretreatment of Trpm2-knockout bone marrow-derived macrophages with HO-1 inducer markedly increased HO-1 expression and decreased bacterial burden. Pretreatment of Trpm2-knockout mice with HO-1 inducer reversed the susceptibility of Trpm2-knockout mice to sepsis by enhancing the bacterial clearance. In addition, septic patients with lower monocytic TRPM2 and HO-1 messenger RNA levels had a worse outcome compared with septic patients with normal monocytic TRPM2 and HO-1 messenger RNA levels. TRPM2 levels correlated with HO-1 levels in septic patients (r = 0.675, P = 0.001). CONCLUSION The study data demonstrate a protective role of TRPM2 in controlling bacterial clearance during polymicrobial sepsis possibly by regulating HO-1 expression.
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Weber B, Schuster S, Zysset D, Rihs S, Dickgreber N, Schürch C, Riether C, Siegrist M, Schneider C, Pawelski H, Gurzeler U, Ziltener P, Genitsch V, Tacchini-Cottier F, Ochsenbein A, Hofstetter W, Kopf M, Kaufmann T, Oxenius A, Reith W, Saurer L, Mueller C. TREM-1 deficiency can attenuate disease severity without affecting pathogen clearance. PLoS Pathog 2014; 10:e1003900. [PMID: 24453980 PMCID: PMC3894224 DOI: 10.1371/journal.ppat.1003900] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 12/10/2013] [Indexed: 12/02/2022] Open
Abstract
Triggering receptor expressed on myeloid cells-1 (TREM-1) is a potent amplifier of pro-inflammatory innate immune reactions. While TREM-1-amplified responses likely aid an improved detection and elimination of pathogens, excessive production of cytokines and oxygen radicals can also severely harm the host. Studies addressing the pathogenic role of TREM-1 during endotoxin-induced shock or microbial sepsis have so far mostly relied on the administration of TREM-1 fusion proteins or peptides representing part of the extracellular domain of TREM-1. However, binding of these agents to the yet unidentified TREM-1 ligand could also impact signaling through alternative receptors. More importantly, controversial results have been obtained regarding the requirement of TREM-1 for microbial control. To unambiguously investigate the role of TREM-1 in homeostasis and disease, we have generated mice deficient in Trem1. Trem1−/− mice are viable, fertile and show no altered hematopoietic compartment. In CD4+ T cell- and dextran sodium sulfate-induced models of colitis, Trem1−/− mice displayed significantly attenuated disease that was associated with reduced inflammatory infiltrates and diminished expression of pro-inflammatory cytokines. Trem1−/− mice also exhibited reduced neutrophilic infiltration and decreased lesion size upon infection with Leishmania major. Furthermore, reduced morbidity was observed for influenza virus-infected Trem1−/− mice. Importantly, while immune-associated pathologies were significantly reduced, Trem1−/− mice were equally capable of controlling infections with L. major, influenza virus, but also Legionella pneumophila as Trem1+/+ controls. Our results not only demonstrate an unanticipated pathogenic impact of TREM-1 during a viral and parasitic infection, but also indicate that therapeutic blocking of TREM-1 in distinct inflammatory disorders holds considerable promise by blunting excessive inflammation while preserving the capacity for microbial control. Triggering receptor expressed on myeloid cells-1 (TREM-1) is an immune receptor expressed by myeloid cells that has the capacity to augment pro-inflammatory responses in the context of a microbial infection. While a TREM-1-amplified response likely serves the efficient clearance of pathogens, it also bears the potential to cause substantial tissue damage or even death. Hence, TREM-1 appears a possible therapeutic target for tempering deleterious host-pathogen interactions. However, in models of bacterial sepsis controversial findings have been obtained regarding the requirement of TREM-1 for bacterial control - depending on the overall degree of the TREM-1 blockade that was achieved. In order to conclusively investigate harmful versus essential functions of TREM-1 in vivo, we have generated mice deficient in Trem1. Trem1−/− mice were subjected to experimentally-induced intestinal inflammation (as a model of a non-infectious, yet microbial-driven disease) and also analysed following infections with Leishmania major, influenza virus and Legionella pneumophila. Across all models analysed, Trem1−/− mice showed substantially reduced immune-associated disease. We thus describe a previously unanticipated pathogenic role for TREM-1 also during a parasitic and viral infection. Importantly, our data suggest that in certain diseases microbial control can be achieved in the context of blunted inflammation in the absence of TREM-1.
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Affiliation(s)
- Benjamin Weber
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Steffen Schuster
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Daniel Zysset
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Silvia Rihs
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Nina Dickgreber
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | - Christian Schürch
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Carsten Riether
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Mark Siegrist
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | | | - Helga Pawelski
- Institute of Molecular Health Sciences, ETH Zurich, Zurich, Switzerland
| | - Ursina Gurzeler
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | | | - Vera Genitsch
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
| | | | - Adrian Ochsenbein
- Department of Clinical Research, University of Bern, Bern, Switzerland
- Department of Medical Oncology, University of Bern, Bern, Switzerland
| | - Willy Hofstetter
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Manfred Kopf
- Institute of Molecular Health Sciences, ETH Zurich, Zurich, Switzerland
| | - Thomas Kaufmann
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | | | - Walter Reith
- Department of Pathology and Immunology, Centre Medical Universitaire, Geneva, Switzerland
| | - Leslie Saurer
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
- * E-mail: (LS); (CM)
| | - Christoph Mueller
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
- * E-mail: (LS); (CM)
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Bostanci N, Thurnheer T, Aduse-Opoku J, Curtis MA, Zinkernagel AS, Belibasakis GN. Porphyromonas gingivalis regulates TREM-1 in human polymorphonuclear neutrophils via its gingipains. PLoS One 2013; 8:e75784. [PMID: 24124513 DOI: 10.1371/journal.pone.0075784] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/21/2013] [Indexed: 12/03/2022] Open
Abstract
The Triggering Receptor Expressed on Myeloid cells 1 (TREM-1) is a cell surface receptor of the immunoglobulin superfamily, with the capacity to amplify pro-inflammatory cytokine production and regulate apoptosis. Polymorphonuclear neutrophils (PMNs) are the first line of defence against infection, and a major source of TREM-1. Porphyromonas gingivalis is a Gram-negative anaerobe highly implicated in the inflammatory processes governing periodontal disease, which is characterized by the destruction of the tooth-supporting tissues. It expresses a number of virulence factors, including the cysteine proteinases (or gingipains). The aim of this in vitro study was to investigate the effect of P. gingivalis on TREM-1 expression and production by primary human PMNs, and to evaluate the role of its gingipains in this process. After 4 h of challenge, P. gingivalis enhanced TREM-1 expression as identified by quantitative real-time PCR. This was followed by an increase in soluble (s)TREM-1 secretion over a period of 18 h, as determined by ELISA. At this time-point, the P. gingivalis-challenged PMNs exhibited diminished TREM-1 cell-membrane staining, as identified by flow cytometry and confocal laser scanning microscopy. Furthermore engagement of TREM-1, by means of anti-TREM-1 antibodies, enhanced the capacity of P. gingivalis to stimulate interleukin (IL)-8 production. Conversely, antagonism of TREM-1 using a synthetic peptide resulted in reduction of IL-8 secretion. Using isogenic P. gingivalis mutant strains, we identified the Arg-gingipain to be responsible for shedding of sTREM-1 from the PMN surface, whereas the Lys-gingipain had the capacity to degrade TREM-1. In conclusion, the differential regulation of TREM-1 by the P. gingivalis gingipains may present a novel mechanism by which P. gingivalis manipulates the host innate immune response helping to establish chronic periodontal inflammation.
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