1
|
Yin Y, Yang H, Li R, Wu G, Qin Q, Tang Y. A systematic review of the role of TREM2 in Alzheimer's disease. Chin Med J (Engl) 2024; 137:1684-1694. [PMID: 38915213 PMCID: PMC11268819 DOI: 10.1097/cm9.0000000000003000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Indexed: 06/26/2024] Open
Abstract
BACKGROUND Given the established genetic linkage between triggering receptors expressed on myeloid cells 2 (TREM2) and Alzheimer's disease (AD), an expanding research body has delved into the intricate role of TREM2 within the AD context. However, a conflicting landscape of outcomes has emerged from both in vivo and in vitro investigations. This study aimed to elucidate the multifaceted nuances and gain a clearer comprehension of the role of TREM2. METHODS PubMed database was searched spanning from its inception to January 2022. The search criteria took the form of ("Alzheimer's disease" OR "AD") AND ("transgenic mice model" OR "transgenic mouse model") AND ("Triggering receptor expressed on myeloid cells" OR "TREM2"). Inclusion criteria consisted of the following: (1) publication of original studies in English; (2) utilization of transgenic mouse models for AD research; and (3) reports addressing the subject of TREM2. RESULTS A total of 43 eligible articles were identified. Our analysis addresses four pivotal queries concerning the interrelation of TREM2 with microglial function, Aβ accumulation, tau pathology, and inflammatory processes. However, the diverse inquiries posed yielded inconsistent responses. Nevertheless, the inconsistent roles of TREM2 within these AD mouse models potentially hinge upon factors such as age, sex, brain region, model type, and detection methodologies. CONCLUSIONS This review substantiates the evolving understanding of TREM2's disease progression-dependent impacts. Furthermore, it reviews the interplay between TREM2 and its effects across diverse tissues and temporal stages.
Collapse
Affiliation(s)
- Yunsi Yin
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Hanchen Yang
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Ruiyang Li
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Guangshan Wu
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Qi Qin
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| | - Yi Tang
- Department of Neurology & Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing 100053, China
| |
Collapse
|
2
|
Bharadwaj S, Groza Y, Mierzwicka JM, Malý P. Current understanding on TREM-2 molecular biology and physiopathological functions. Int Immunopharmacol 2024; 134:112042. [PMID: 38703564 DOI: 10.1016/j.intimp.2024.112042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 05/06/2024]
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM-2), a glycosylated receptor belonging to the immunoglobin superfamily and especially expressed in the myeloid cell lineage, is frequently explained as a reminiscent receptor for both adaptive and innate immunity regulation. TREM-2 is also acknowledged to influence NK cell differentiation via the PI3K and PLCγ signaling pathways, as well as the partial activation or direct inhibition of T cells. Additionally, TREM-2 overexpression is substantially linked to cell-specific functions, such as enhanced phagocytosis, reduced toll-like receptor (TLR)-mediated inflammatory cytokine production, increased transcription of anti-inflammatory cytokines, and reshaped T cell function. Whereas TREM-2-deficient cells exhibit diminished phagocytic function and enhanced proinflammatory cytokines production, proceeding to inflammatory injuries and an immunosuppressive environment for disease progression. Despite the growing literature supporting TREM-2+ cells in various diseases, such as neurodegenerative disorders and cancer, substantial facets of TREM-2-mediated signaling remain inadequately understood relevant to pathophysiology conditions. In this direction, herein, we have summarized the current knowledge on TREM-2 biology and cell-specific TREM-2 expression, particularly in the modulation of pivotal TREM-2-dependent functions under physiopathological conditions. Furthermore, molecular regulation and generic biological relevance of TREM-2 are also discussed, which might provide an alternative approach for preventing or reducing TREM-2-associated deformities. At last, we discussed the TREM-2 function in supporting an immunosuppressive cancer environment and as a potential drug target for cancer immunotherapy. Hence, summarized knowledge of TREM-2 might provide a window to overcome challenges in clinically effective therapies for TREM-2-induced diseases in humans.
Collapse
Affiliation(s)
- Shiv Bharadwaj
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic.
| | - Yaroslava Groza
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Joanna M Mierzwicka
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Petr Malý
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV Research Center, Průmyslová 595, 252 50 Vestec, Czech Republic.
| |
Collapse
|
3
|
Henningfield CM, Soni N, Lee RW, Sharma R, Cleland JL, Green KN. Selective targeting and modulation of plaque associated microglia via systemic hydroxyl dendrimer administration in an Alzheimer's disease mouse model. Alzheimers Res Ther 2024; 16:101. [PMID: 38711159 PMCID: PMC11071231 DOI: 10.1186/s13195-024-01470-3] [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: 10/26/2023] [Accepted: 04/29/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND In Alzheimer's disease (AD), microglia surround extracellular plaques and mount a sustained inflammatory response, contributing to the pathogenesis of the disease. Identifying approaches to specifically target plaque-associated microglia (PAMs) without interfering in the homeostatic functions of non-plaque associated microglia would afford a powerful tool and potential therapeutic avenue. METHODS Here, we demonstrated that a systemically administered nanomedicine, hydroxyl dendrimers (HDs), can cross the blood brain barrier and are preferentially taken up by PAMs in a mouse model of AD. As proof of principle, to demonstrate biological effects in PAM function, we treated the 5xFAD mouse model of amyloidosis for 4 weeks via systemic administration (ip, 2x weekly) of HDs conjugated to a colony stimulating factor-1 receptor (CSF1R) inhibitor (D-45113). RESULTS Treatment resulted in significant reductions in amyloid-beta (Aβ) and a stark reduction in the number of microglia and microglia-plaque association in the subiculum and somatosensory cortex, as well as a downregulation in microglial, inflammatory, and synaptic gene expression compared to vehicle treated 5xFAD mice. CONCLUSIONS This study demonstrates that systemic administration of a dendranib may be utilized to target and modulate PAMs.
Collapse
Affiliation(s)
- Caden M Henningfield
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Ryan W Lee
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA
| | - Rishi Sharma
- Ashvattha Therapeutics, Inc, Redwood City, CA, 94065, USA
| | | | - Kim N Green
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697, USA.
| |
Collapse
|
4
|
Matos ADO, Dantas PHDS, Queiroz HAGDB, Silva-Sales M, Sales-Campos H. TREM-2: friend or foe in infectious diseases? Crit Rev Microbiol 2024; 50:1-19. [PMID: 36403150 DOI: 10.1080/1040841x.2022.2146481] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/07/2022] [Indexed: 11/21/2022]
Abstract
The triggering receptor expressed on myeloid cells-2 (TREM-2) is an immune receptor expressed on immune and non-immune cells, more frequently investigated in neurodegenerative disorders and considered a marker for microglia activation. In infectious diseases, the receptor was initially believed to be an anti-inflammatory molecule, opposing the inflammation triggered by TREM-1. Currently, TREM-2 is associated with different aspects in response to infectious stimuli, including the induction of bacterial phagocytosis and clearance, containment of exacerbated pro-inflammatory responses, induction of M2 differentiation and activation of Th1 lymphocytes, besides of neurological damage after viral infection. Here, we present and discuss results published in the last two decades regarding the expression, activation and functions of TREM-2 during the course of bacterial, viral, fungal and parasitic infections. A surprisingly plasticity was observed regarding the roles of the receptor in the aforementioned contexts, which largely varied according to the cell/organ and pathogen type, besides influencing disease outcome. Therefore, our review aimed to critically overview the role of TREM-2 in infectious diseases, highlighting its potential to be used as a clinical biomarker or therapeutic target.
Collapse
Affiliation(s)
| | | | | | - Marcelle Silva-Sales
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Brazil
| | | |
Collapse
|
5
|
Wu Z, Yang S, Fang X, Shu Q, Chen Q. Function and mechanism of TREM2 in bacterial infection. PLoS Pathog 2024; 20:e1011895. [PMID: 38236825 PMCID: PMC10796033 DOI: 10.1371/journal.ppat.1011895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2024] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2), which is a lipid sensing and phagocytosis receptor, plays a key role in immunity and inflammation in response to pathogens. Here, we review the function and signaling of TREM2 in microbial binding, engulfment and removal, and describe TREM2-mediated inhibition of inflammation by negatively regulating the Toll-like receptor (TLR) response. We further illustrate the role of TREM2 in restoring organ homeostasis in sepsis and soluble TREM2 (sTREM2) as a diagnostic marker for sepsis-associated encephalopathy (SAE). Finally, we discuss the prospect of TREM2 as an interesting therapeutic target for sepsis.
Collapse
Affiliation(s)
- Zehua Wu
- Department of the Clinical Research Center, Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China
| | - Shiyue Yang
- Department of Anesthesiology, First Affiliated Hospital of Soochow University, Soochow, People’s Republic of China
| | - Xiangming Fang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China
| | - Qiang Shu
- Department of the Clinical Research Center, Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China
- Key Laboratory of Diagnosis and Treatment of Neonatal Diseases of Zhejiang Province, Hangzhou, People’s Republic of China
| | - Qixing Chen
- Department of the Clinical Research Center, Children’s Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China
- Key Laboratory of Diagnosis and Treatment of Neonatal Diseases of Zhejiang Province, Hangzhou, People’s Republic of China
| |
Collapse
|
6
|
La Rosa F, Agostini S, Piancone F, Marventano I, Hernis A, Fenoglio C, Galimberti D, Scarpini E, Saresella M, Clerici M. TREM2 Expression and Amyloid-Beta Phagocytosis in Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24108626. [PMID: 37239970 DOI: 10.3390/ijms24108626] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Alzheimer's Disease is the most common form of dementia; its key pathological findings include the deposition of extracellular-neurotoxic-plaques composed of amyloid-beta (Ab). AD-pathogenesis involves mechanisms that operate outside the brain, and new researches indicate that peripheral inflammation is an early event in the disease. Herein, we focus on a receptor known as triggering-receptor-expressed-on-myeloid-cells2 (TREM2), which promotes the optimal immune cells function required to attenuate AD-progression and is, therefore, a potential target as peripheral diagnostic and prognostic-biomarker for Alzheimer's Disease. The objective of this exploratory study was to analyze: (1) soluble-TREM2 (sTREM2) plasma and cerebrospinal fluid concentration, (2) TREM2-mRNA, (3) the percentage of TREM2-expressing monocytes, and (4) the concentration of miR-146a-5p and miR-34a-5p suspected to influence TREM2 transcription. Experiments were performed on PBMC collected by 15AD patients and 12age-matched healthy controls that were unstimulated or treated in inflammatory (LPS) conditions and Ab42 for 24 h; Aβ42-phagocytosis was also analyzed by AMNIS FlowSight. Results although preliminary, due to limitations by the small sample-size, showed that in AD compared to HC: TREM2 expressing monocytes were reduced, plasma sTREM2 concentration and TREM2-mRNA were significantly upregulated and Ab42-phagocytosis was diminished (for all p < 0.05). miR-34a-5p expression was reduced (p = 0.02) as well in PBMC of AD, and miR-146 was only observed in AD cells (p = 0.0001).
Collapse
Affiliation(s)
| | | | | | | | - Ambra Hernis
- IRCCS Fondazione Don Carlo Gnocchi, 20147 Milan, Italy
| | - Chiara Fenoglio
- Department of Pathophysiology and Transplantation, University of Milan, 20100 Milan, Italy
| | - Daniela Galimberti
- Fondazione Ca' Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20100 Milan, Italy
| | - Elio Scarpini
- Fondazione Ca' Granda, IRCCS Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | | | - Mario Clerici
- IRCCS Fondazione Don Carlo Gnocchi, 20147 Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, 20100 Milan, Italy
| |
Collapse
|
7
|
Luo Q, Deng D, Li Y, Shi H, Zhao J, Qian Q, Wang W, Cai J, Yu W, Liu J. TREM2 Insufficiency Protects against Pulmonary Fibrosis by Inhibiting M2 Macrophage Polarization. Int Immunopharmacol 2023; 118:110070. [PMID: 37003186 DOI: 10.1016/j.intimp.2023.110070] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/24/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023]
Abstract
Rationale Idiopathic pulmonary fibrosis (IPF) is a lung disease with high mortality, limited treatment options and an unknown aetiology. M2 macrophages play a critical role in the pathological process of IPF. Triggering receptor expressed on myeloid cells-2 (TREM2) participates in the regulation of macrophages, although its role in IPF remains elusive. METHODS This study examined the role of TREM2 in macrophage regulation using a well-established bleomycin (BLM)-induced pulmonary fibrosis (PF) mouse model. TREM2 insufficiency was induced by intratracheal treatment with TREM2-specific siRNA. The effects of TREM2 on IPF were evaluated using histological staining and molecular biological methods. RESULTS TREM2 expression levels were significantly elevated in the lungs of IPF patients and mice with BLM-induced pulmonary fibrosis mice. Bioinformatics analysis revealed that IPF patients with higher TREM2 expression had a shorter survival time, and that TREM2 expression was closely associated with fibroblasts and M2 macrophages. Gene Ontology (GO) enrichment analysis showed that found TREM2-related differentially expressed genes (DEGs) were associated with inflammatory responses, extracellular matrix (ECM) and collagen formation. Single-cell RNA sequencing analysis revealed that TREM2 was predominantly expressed in macrophages. TREM2 insufficiency inhibited BLM-induced pulmonary fibrosis and M2 macrophage polarization. Mechanistic studies showed that TREM2 insufficiency suppressed the activation of STAT6 and the expression of fibrotic factors such as Fibronectin (Fib), Collagen I (Col I) and α- smooth muscle actin (α-SMA). CONCLUSION Our study showed that TREM2 insufficiency might alleviate pulmonary fibrosis possibly through macrophage polarization regulation via STAT6 activation, providing a promising macrophage-related approach for the clinical therapy of pulmonary fibrosis.
Collapse
Affiliation(s)
- Qiujie Luo
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Dawei Deng
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Yang Li
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Hongjie Shi
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Jinping Zhao
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Qiaofeng Qian
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Wei Wang
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Jie Cai
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China
| | - Wenjun Yu
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China.
| | - Jinping Liu
- Department of Cardiovascular Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Provincial Engineering Research Center of Minimally Invasive Cardiovascular Surgery, Wuhan 430071, China; Wuhan Clinical Research Center for Minimally Invasive Treatment of Structural Heart Disease, Wuhan 430071, China.
| |
Collapse
|
8
|
Consecutive Injection of High-Dose Lipopolysaccharide Modulates Microglia Polarization via TREM2 to Alter Status of Septic Mice. Brain Sci 2023; 13:brainsci13010126. [PMID: 36672106 PMCID: PMC9856382 DOI: 10.3390/brainsci13010126] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/29/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The neuroinflammation of the central nervous system (CNS) is a prevalent syndrome of brain dysfunction secondary to severe sepsis and is regulated by microglia. Triggering the receptor expressed on myeloid cells 2 (TREM2) is known to have protective functions that modulate the microglial polarization of M2 type to reduce inflammatory responses, thereby improving cognition. METHODS We examined the effect of TREM2 on the polarization state of microglia during the progression of neuroinflammation. After consecutive intraperitoneal injections of lipopolysaccharide for 7 days, we evaluated the inflammation of a septic mice model by hematoxylin-eosin (H&E) and electron microscopy, and we used immunofluorescence (IF) assays and Western blotting to visualize hippocampal sections in C57BL/6 mice to assess TREM2 expression. In addition, we analyzed the state of microglia polarization with quantitative RT-PCR. RESULT The consecutive injection of LPS for 4 days elevated systemic inflammation and caused behavioral cognitive dysfunction in the septic model. However, on Day 7, the neuroinflammation was considerably attenuated. Meanwhile, TREM2 decreased on Day 4 and increased on Day 7 in vivo. Consistently, LPS could reduce the expression of TREM2 while IFN-β enhanced TREM2 expression in vitro. TREM2 regulated the microglial M1 phenotype's conversion to the M2 phenotype. CONCLUSION Our aim in this study was to investigate the interconnection between microglia polarization and TREM2 in neuroinflammation. Our results suggested that IFN-β could modulate TREM2 expression to alter the polarization state of microglia, thereby reducing LPS-induced neuroinflammation. Therefore, TREM2 is a novel potential therapeutic target for neuroinflammation.
Collapse
|
9
|
Gawish R, Maier B, Obermayer G, Watzenboeck ML, Gorki AD, Quattrone F, Farhat A, Lakovits K, Hladik A, Korosec A, Alimohammadi A, Mesteri I, Oberndorfer F, Oakley F, Brain J, Boon L, Lang I, Binder CJ, Knapp S. A neutrophil-B-cell axis impacts tissue damage control in a mouse model of intraabdominal bacterial infection via Cxcr4. eLife 2022; 11:e78291. [PMID: 36178806 PMCID: PMC9525059 DOI: 10.7554/elife.78291] [Citation(s) in RCA: 6] [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: 03/01/2022] [Accepted: 09/16/2022] [Indexed: 11/13/2022] Open
Abstract
Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multiorgan failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a mouse model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils include upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted disease tolerance by improving tissue damage control via the suppression of neutrophils' tissue-damaging properties. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue damage control and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis.
Collapse
Affiliation(s)
- Riem Gawish
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Barbara Maier
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Georg Obermayer
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
- Department of Laboratory Medicine, Medical University of ViennaViennaAustria
| | - Martin L Watzenboeck
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Anna-Dorothea Gorki
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Federica Quattrone
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Asma Farhat
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Karin Lakovits
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
| | - Anastasiya Hladik
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
| | - Ana Korosec
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
| | - Arman Alimohammadi
- Department of Medicine II, Division of Cardiology, Medical University of ViennaViennaAustria
| | - Ildiko Mesteri
- Department of Pathology, Medical University ViennaViennaAustria
| | | | - Fiona Oakley
- Newcastle Fibrosis Research Group, Biosciences Institute, Newcastle UniversityNewcastleUnited Kingdom
| | - John Brain
- Newcastle Fibrosis Research Group, Biosciences Institute, Newcastle UniversityNewcastleUnited Kingdom
| | | | - Irene Lang
- Department of Medicine II, Division of Cardiology, Medical University of ViennaViennaAustria
| | - Christoph J Binder
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
- Department of Laboratory Medicine, Medical University of ViennaViennaAustria
| | - Sylvia Knapp
- Department of Medicine I, Laboratory of Infection Biology, Medical University ViennaViennaAustria
- Ce-M-M-, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| |
Collapse
|
10
|
Hoogland ICM, Yik J, Westhoff D, Engelen-Lee JY, Valls Seron M, Man WK, Houben-Weerts JHPM, Tanck MW, van Westerloo DJ, van der Poll T, van Gool WA, van de Beek D. Microglial Response in Triggering Receptor Expressed on Myeloid Cells 2 (Trem2) Knock-Out Mice After Systemic Stimulation with Escherichia Coli. Neurosci Lett 2022; 790:136894. [PMID: 36183964 DOI: 10.1016/j.neulet.2022.136894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/27/2022] [Accepted: 09/27/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Systemic infection is an important risk factor for delirium, associated with neurodegeneration and subsequent cognitive impairment in older people. Microglial cell response is a known key player in this process and we hypothesize that the triggering receptor expressed on myeloid cells 2 (TREM2) plays an important role in the regulation of this response. METHODS 8- to 10-week old male wild-type (WT) and TREM2 knock-out (Trem2-/-) mice were intraperitoneally inoculated with live Escherichia coli (E. coli) or saline. After inoculation, all mice were treated with ceftriaxone (an antimicrobial drug) at 12 and 24 hours and were sacrificed after 2 and 3 days. Microglial response was determined by immunohistochemical staining with an ionized calcium-binding adaptor molecule 1 (Iba-1) antibody and flow cytometry. mRNA expression of pro- and anti-inflammatory mediators was measured to quantify the inflammatory response. RESULTS We observed increased Iba-1 positive cells number in thalamus of Trem2-/- mice at 3d after inoculation compared to WT mice (mean 120 cell/mm2 [SD 8] vs. 105 cell/mm2 [SD 11]; p=0.03). Flow cytometry showed no differences in forward scatter or expression of CD11b, CD45 and CD14 between WT and Trem2-/- mice. The brain mRNA expression levels of tumor necrosis factor alpha (TNF-α) of Trem2-/- mice at 2d were higher compared to WT mice (p=0.003). Higher mRNA expression of interleukin 1 beta (IL-1β), Iba-1, CD11b and mitogen-activated protein kinase 1 (MAPK-1) was found in brain of WT mice at 2d compared to Trem2-/- mice (respectively p=0.02; p=0.001; p=0.03 and p=0.02). In spleen there were no differences in inflammatory mediators, between WT and Trem2-/- mice. INTERPRETATION Although the loss of function of TREM2 during systemic infection led to an increased number of activated microglia in the thalamus, we did not observe a consistent increase in expression of inflammatory genes in the brain. The role of TREM2 in the neuro-inflammatory response following systemic infection therefore appears to be limited.
Collapse
Affiliation(s)
- Inge C M Hoogland
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| | - Jutka Yik
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands
| | - Dunja Westhoff
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| | - Joo-Yeon Engelen-Lee
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| | - Merche Valls Seron
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands
| | - Wing-Kit Man
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands
| | - Judith H P M Houben-Weerts
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| | - Michael W Tanck
- Department of Clinical Epidemiology, Amsterdam University Medical Centres, Location Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | | | - Tom van der Poll
- Centre of Experimental Molecular Medicine, Amsterdam University Medical Centres, Location Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | - Willem A van Gool
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| | - Diederik van de Beek
- Department of Neurology, Amsterdam University Medical Centres, Location Academic Medical Centre, Amsterdam Neuroscience, University of Amsterdam, PO Box 22660, 1100DD Amsterdam, The Netherlands.
| |
Collapse
|
11
|
Long HZ, Zhou ZW, Cheng Y, Luo HY, Li FJ, Xu SG, Gao LC. The Role of Microglia in Alzheimer’s Disease From the Perspective of Immune Inflammation and Iron Metabolism. Front Aging Neurosci 2022; 14:888989. [PMID: 35847685 PMCID: PMC9284275 DOI: 10.3389/fnagi.2022.888989] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/13/2022] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s disease (AD), the most common type of senile dementia, includes the complex pathogenesis of abnormal deposition of amyloid beta-protein (Aβ), phosphorylated tau (p-tau) and neuroimmune inflammatory. The neurodegenerative process of AD triggers microglial activation, and the overactivation of microglia produces a large number of neuroimmune inflammatory factors. Microglia dysfunction can lead to disturbances in iron metabolism and enhance iron-induced neuronal degeneration in AD, while elevated iron levels in brain areas affect microglia phenotype and function. In this manuscript, we firstly discuss the role of microglia in AD and then introduce the role of microglia in the immune-inflammatory pathology of AD. Their role in AD iron homeostasis is emphasized. Recent studies on microglia and ferroptosis in AD are also reviewed. It will help readers better understand the role of microglia in iron metabolism in AD, and provides a basis for better regulation of iron metabolism disorders in AD and the discovery of new potential therapeutic targets for AD.
Collapse
Affiliation(s)
- Hui-Zhi Long
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Zi-Wei Zhou
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Yan Cheng
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Hong-Yu Luo
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Feng-Jiao Li
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Shuo-Guo Xu
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
| | - Li-Chen Gao
- School of Pharmacy, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang, China
- *Correspondence: Li-Chen Gao,
| |
Collapse
|
12
|
Variant TREM2 Signaling in Alzheimer's Disease. J Mol Biol 2022; 434:167470. [PMID: 35120968 DOI: 10.1016/j.jmb.2022.167470] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease is the most common form of dementia, accounting for as much as three-quarters of cases globally with individuals in low- and middle-income countries being worst affected. Numerous risk factors for the disease have been identified and our understanding of gene-environment interactions have shed light on several gene variants that contribute to the most common, sporadic form of Alzheimer's disease. Triggering Receptor Expressed on Myeloid cells 2 (TREM2) is an important receptor that is crucial to the functioning of microglial cells, and variants of this protein have been found to be associated with a significantly increased risk of Alzheimer's disease. Several studies have elucidated the signaling processes involved in the normal functioning of the TREM2 receptor. However, current knowledge of the idiosyncrasies of the signaling processes triggered by stimulation of the variants of this receptor is limited. In this review, we examine the existing literature and highlight the effects that various receptor variants have on downstream signaling processes and discuss how these perturbations may affect physiologic processes in Alzheimer's disease. Despite the fact that this is a territory yet to be fully explored, the studies that currently exist report mostly quantitative effects on signaling. More mechanistic studies with the aim of providing qualitative results in terms of downstream signaling among these receptor variants are warranted. Such studies will provide better opportunities of identifying therapeutic targets that may be exploited in designing new drugs for the management of Alzheimer's disease.
Collapse
|
13
|
Cao Y, Wang Y, Peng N, Xiao J, Wang S, Fu C. The ratio of urinary TREM-1/TREM-2 mRNA expression in chronic kidney disease and renal fibrosis. Ann Med 2021; 53:1010-1018. [PMID: 34176389 PMCID: PMC8245072 DOI: 10.1080/07853890.2021.1912384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The non-invasive identification of novel renal fibrosis biomarkers needs to be further studied. METHODS We collected urine samples from 77 biopsy-proven CKD patients and 15 healthy controls. The expression of urinary TREM-1 and TREM-2 was measured and the correlation with renal function parameter and pathological indicators was performed. The receiver operating characteristic (ROC) curve for the diagnosis of renal fibrosis was calculated. The protein expression of TREM-1 and TREM-2 in kidney tissues was measured. RESULTS The TREM-1/TREM-2 ratio was decreased in CKD patients and correlated with serum creatinine, estimated glomerular filtration rate and cystatin c. Further, the TREM-1/TREM-2 ratio was significantly decreased in moderate-severe fibrosis patients compared with none-mild renal fibrosis. TREM-1/TREM-2 ratio was correlated with the score of tubulointerstitial fibrosis (TIF) and the score of glomerular sclerosis. The ROC curve showed that the urinary TREM-1/TREM-2 ratio can diagnosemoderate-severe renal fibrosis at a cut-off value of 1.338 with a sensitivity of 86.4% and specificity of 81.8%. In human moderate-severe fibrosis kidney tissue, the protein expression of TREM-1 was lower and the TREM-2 was higher than none-mild fibrosis kidney tissue. CONCLUSION Urinary TREM-1/TREM-2 ratio was a potential biomarker for the diagnosis of renal fibrosis in CKD patients.
Collapse
Affiliation(s)
- Yuhan Cao
- Department of Nephrology, Yi Ji Shan Hospital Affiliated to Wan Nan Medical College, China.,Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution (Wann Nan Medical College), China
| | - Yuwei Wang
- Department of Nephrology, Yi Ji Shan Hospital Affiliated to Wan Nan Medical College, China
| | - Nana Peng
- School of Clinical Medicine, Wan Nan Medical College, China
| | - Jie Xiao
- School of Anesthesiology, Wan Nan Medical College, China
| | - Sufen Wang
- Department of Pathology, Yi Ji Shan hospital affiliated to Wan Nan Medical College, China
| | - Cong Fu
- Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution (Wann Nan Medical College), China.,Department of Cardiology, Yi Ji Shan hospital affiliated to Wan Nan Medical College, China
| |
Collapse
|
14
|
Wu Y, Wu M, Ming S, Zhan X, Hu S, Li X, Yin H, Cao C, Liu J, Li J, Wu Z, Zhou J, Liu L, Gong S, He D, Huang X. TREM-2 promotes Th1 responses by interacting with the CD3ζ-ZAP70 complex following Mycobacterium tuberculosis infection. J Clin Invest 2021; 131:137407. [PMID: 34623322 DOI: 10.1172/jci137407] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/20/2021] [Indexed: 12/16/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM-2) is a modulator of pattern recognition receptors on innate immune cells that regulates the inflammatory response. However, the role of TREM-2 in in vivo models of infection and inflammation remains controversial. Here, we demonstrated that TREM-2 expression on CD4+ T cells was induced by Mycobacterium tuberculosis infection in both humans and mice and positively associated with T cell activation and an effector memory phenotype. Activation of TREM-2 in CD4+ T cells was dependent on interaction with the putative TREM-2 ligand expressed on DCs. Unlike the observation in myeloid cells that TREM-2 signals through DAP12, in CD4+ T cells, TREM-2 interacted with the CD3ζ-ZAP70 complex as well as with the IFN-γ receptor, leading to STAT1/-4 activation and T-bet transcription. In addition, an infection model using reconstituted Rag2-/- mice (with TREM-2-KO vs. WT cells or TREM-2+ vs. TREM-2-CD4+ T cells) or CD4+ T cell-specific TREM-2 conditional KO mice demonstrated that TREM-2 promoted a Th1-mediated host defense against M. tuberculosis infection. Taken together, these findings reveal a critical role of TREM-2 in evoking proinflammatory Th1 responses that may provide potential therapeutic targets for infectious and inflammatory diseases.
Collapse
Affiliation(s)
- Yongjian Wu
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Minhao Wu
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Siqi Ming
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, The Second Affiliated Hospital of the Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Xiaoxia Zhan
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Shengfeng Hu
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Xingyu Li
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Huan Yin
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Can Cao
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Jiao Liu
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Jinai Li
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Zhilong Wu
- The Fourth People's Hospital of Foshan, Foshan, China
| | - Jie Zhou
- The Fourth People's Hospital of Foshan, Foshan, China
| | - Lei Liu
- National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, The Second Affiliated Hospital of the Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Sitang Gong
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Duanman He
- Shantou No. 3 People's Hospital, Shantou, Guangdong Province, China
| | - Xi Huang
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Guangdong Provincial Engineering Research Center of Molecular Imaging, Guangdong Provincial Key Laboratory of Biomedical Imaging, and Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China.,National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, The Second Affiliated Hospital of the Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| |
Collapse
|
15
|
Xu X, Du L, Jiang J, Yang M, Wang Z, Wang Y, Tang T, Fu X, Hao J. Microglial TREM2 Mitigates Inflammatory Responses and Neuronal Apoptosis in Angiotensin II-Induced Hypertension in Middle-Aged Mice. Front Aging Neurosci 2021; 13:716917. [PMID: 34489683 PMCID: PMC8417947 DOI: 10.3389/fnagi.2021.716917] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/16/2021] [Indexed: 11/15/2022] Open
Abstract
Growing evidence suggests that hypertension and aging are prominent risk factors for the development of late-onset Alzheimer's disease (LOAD) by inducement of neuroinflammation. Recent study showed that neuroinflammation via activated microglia induces reactive astrocytes, termed A1 astrocytes, that highly upregulate numerous classical complement cascade genes that are destructive to neurons in neurodegeneration diseases. Moreover, triggering receptor expressed on myeloid cells 2 (TREM2) is considered as one of the strongest single-allele genetic risk factors and plays important roles in neuroinflammation for LOAD. However, the mechanisms of microglia in the regulation of A1 astrocytic activation are still not clear. We introduced angiotensin II-induced hypertension in middle-aged mice and found that hypertension-upregulated TREM2 expression and A1 astrocytic activation were involved in neuroinflammation in the animal models used in this study. The in vitro results revealed that overexpression of microglial TREM2 not only mitigated microglial inflammatory response but also had salutary effects on reverse A1 astrocytic activation and neuronal toxicity.
Collapse
Affiliation(s)
- Xiaotian Xu
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, United States
| | - Lin Du
- Department of Cardiology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Ming Yang
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Zhaoxia Wang
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Yingge Wang
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Tieyu Tang
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Xuetao Fu
- Department of Neurology, The Affiliated Hospital, Yangzhou University, Yangzhou, China
| | - Jiukuan Hao
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX, United States
| |
Collapse
|
16
|
Arrona Cardoza P, Spillane MB, Morales Marroquin E. Alzheimer's disease and gut microbiota: does trimethylamine N-oxide (TMAO) play a role? Nutr Rev 2021; 80:271-281. [PMID: 33942080 DOI: 10.1093/nutrit/nuab022] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that affects memory and cognitive function. Clinical evidence has put into question our current understanding of AD development, propelling researchers to look into further avenues. Gut microbiota has emerged as a potential player in AD pathophysiology. Lifestyle factors, such as diet, can have negative effects on the gut microbiota and thus host health. A Western-type diet has been highlighted as a risk factor for both gut microbiota alteration as well as AD development. The gut-derived trimethylamine N-oxide (TMAO) has been previously implied in the development of cardiovascular diseases with recent evidence suggesting a plausible role of TMAO in AD development. Therefore, the main goal of the present review is to provide the reader with potential mechanisms of action through which consumption of a Western-type diet could increase AD risk, by acting through microbiota-produced TMAO. Although a link between TMAO and AD is far from definitive, this review will serve as a call for research into this new area of research.
Collapse
Affiliation(s)
- Pablo Arrona Cardoza
- P. Arrona Cardoza is with the Tecnológico de Monterrey, School of Medicine and Health Science, Monterrey, Nuevo Leon, Mexico. M.B Spillane is with the H.C. Drew School of Health and Human Performance, McNeese State University, Lake Charles, Louisiana, USA. E. Morales Marroquin is with the School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA. E. Morales Marroquin is with the Center for Pediatric Population Health, UTHealth School of Public Health and Children's Health System of Texas, Dallas, Texas, USA
| | - Micheil B Spillane
- P. Arrona Cardoza is with the Tecnológico de Monterrey, School of Medicine and Health Science, Monterrey, Nuevo Leon, Mexico. M.B Spillane is with the H.C. Drew School of Health and Human Performance, McNeese State University, Lake Charles, Louisiana, USA. E. Morales Marroquin is with the School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA. E. Morales Marroquin is with the Center for Pediatric Population Health, UTHealth School of Public Health and Children's Health System of Texas, Dallas, Texas, USA
| | - Elisa Morales Marroquin
- P. Arrona Cardoza is with the Tecnológico de Monterrey, School of Medicine and Health Science, Monterrey, Nuevo Leon, Mexico. M.B Spillane is with the H.C. Drew School of Health and Human Performance, McNeese State University, Lake Charles, Louisiana, USA. E. Morales Marroquin is with the School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA. E. Morales Marroquin is with the Center for Pediatric Population Health, UTHealth School of Public Health and Children's Health System of Texas, Dallas, Texas, USA
| |
Collapse
|
17
|
Fu YL, Harrison RE. Microbial Phagocytic Receptors and Their Potential Involvement in Cytokine Induction in Macrophages. Front Immunol 2021; 12:662063. [PMID: 33995386 PMCID: PMC8117099 DOI: 10.3389/fimmu.2021.662063] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
Phagocytosis is an essential process for the uptake of large (>0.5 µm) particulate matter including microbes and dying cells. Specialized cells in the body perform phagocytosis which is enabled by cell surface receptors that recognize and bind target cells. Professional phagocytes play a prominent role in innate immunity and include macrophages, neutrophils and dendritic cells. These cells display a repertoire of phagocytic receptors that engage the target cells directly, or indirectly via opsonins, to mediate binding and internalization of the target into a phagosome. Phagosome maturation then proceeds to cause destruction and recycling of the phagosome contents. Key subsequent events include antigen presentation and cytokine production to alert and recruit cells involved in the adaptive immune response. Bridging the innate and adaptive immunity, macrophages secrete a broad selection of inflammatory mediators to orchestrate the type and magnitude of an inflammatory response. This review will focus on cytokines produced by NF-κB signaling which is activated by extracellular ligands and serves a master regulator of the inflammatory response to microbes. Macrophages secrete pro-inflammatory cytokines including TNFα, IL1β, IL6, IL8 and IL12 which together increases vascular permeability and promotes recruitment of other immune cells. The major anti-inflammatory cytokines produced by macrophages include IL10 and TGFβ which act to suppress inflammatory gene expression in macrophages and other immune cells. Typically, macrophage cytokines are synthesized, trafficked intracellularly and released in response to activation of pattern recognition receptors (PRRs) or inflammasomes. Direct evidence linking the event of phagocytosis to cytokine production in macrophages is lacking. This review will focus on cytokine output after engagement of macrophage phagocytic receptors by particulate microbial targets. Microbial receptors include the PRRs: Toll-like receptors (TLRs), scavenger receptors (SRs), C-type lectin and the opsonic receptors. Our current understanding of how macrophage receptor stimulation impacts cytokine production is largely based on work utilizing soluble ligands that are destined for endocytosis. We will instead focus this review on research examining receptor ligation during uptake of particulate microbes and how this complex internalization process may influence inflammatory cytokine production in macrophages.
Collapse
Affiliation(s)
- Yan Lin Fu
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Rene E. Harrison
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| |
Collapse
|
18
|
Yang S, Yang Y, Wang F, Luo Q, Zhang Y, Zheng F, Shu Q, Chen Q, Fang X. TREM2 Dictates Antibacterial Defense and Viability of Bone Marrow-derived Macrophages during Bacterial Infection. Am J Respir Cell Mol Biol 2021; 65:176-188. [PMID: 33848212 DOI: 10.1165/rcmb.2020-0521oc] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Macrophages undergo profound metabolic reprogramming to join key immunoregulatory functions, which can be initiated by pattern recognition receptors. TREM2 (triggering receptor expressed on myeloid cells 2), a macrophage phagocytic receptor, plays pivotal roles in sepsis by enhancing bacterial clearance, which is associated with regulation of reactive oxygen species (ROS) production. However, how intracellular ROS participate in TREM2-mediated bactericidal activity remains unclear. This study was designed to investigate the organelle source and biological activity of ROS in the context of TREM2-mediated immune defense during Escherichia coli infection. Bone marrow-derived macrophages (BMDMs) were transfected with TREM2-overexpressing adenoviruses or control viruses and challenged with E. coli. The BMDMs were administered to mouse models with local E. coli infection. In addition, monocytic TREM2 expression, NOX2 concentrations, and pyroptosis were detected in patients with bacterial sepsis. General ROS production was found to be comparable between TREM2-overexpressing and control BMDMs upon E. coli challenge. The deficiency of Nox2 led to impaired phagosome degradation and lack of bactericidal ability and abolished TREM2-mediated protective activity against pulmonary E. coli infection. Overexpression of TREM2 suppressed mitochondrial ROS generation, inhibited NLRP3/caspase-1 inflammasome activation, and finally protected BMDMs from gasdermin D-mediated pyroptosis during pulmonary E. coli infection. The protective role of TREM2 was further confirmed in mice with abdominal E. coli infection. Moreover, monocytic TREM2 expression was positively correlated with NOX2 concentrations and negatively correlated with pyroptosis and disease severity in patients with bacterial sepsis. Collectively, TREM2 controls macrophage immune functions by fine-tuning ROS generation and enhances the host defense against bacterial infection. Our data suggest that TREM2 is a promising candidate target for sepsis therapy.
Collapse
Affiliation(s)
- ShiYue Yang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - Yang Yang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - FeiFei Wang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - QinYu Luo
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yan Zhang
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Fei Zheng
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Qiang Shu
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - QiXing Chen
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - XiangMing Fang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| |
Collapse
|
19
|
Ye H, Zhai Q, Fang P, Yang S, Sun Y, Wu S, Huang R, Chen Q, Fang X. Triggering receptor expressed on myeloid Cells-2 (TREM2) inhibits steroidogenesis in adrenocortical cell by macrophage-derived exosomes in lipopolysaccharide-induced septic shock. Mol Cell Endocrinol 2021; 525:111178. [PMID: 33556472 DOI: 10.1016/j.mce.2021.111178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Endogenously produced glucocorticoids exhibit immunomodulating properties and are of pivotal importance for sepsis outcome. Uncontrolled activation of the immune-adrenal crosstalk increases the risk of sepsis-related death. Triggering receptor expressed on myeloid cells-2 (TREM2) is richly expressed on macrophages and has been demonstrated to improve outcome of sepsis by enhancing elimination of pathogens. However, the role and mode of action of macrophage TREM2 on adrenocortical steroidogenesis remains unclear in septic shock. METHODS The acute septic shock model was established by intraperitoneally challenging wild-type (WT) and TREM2 knock-out (Trem2-/-) mice with lipopolysaccharide (LPS, 30 mg/kg). The mice were assessed for TREM2 expression and local inflammation in adrenal gland and for synthesis of corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) in vivo. Bone marrow-derived macrophages or macrophage-derived exosomes were isolated from WT and Trem2-/- mice and were co-cultured with adrenocortical cells. The expression of steroidogenic enzymes and corticosterone production was assessed. RESULTS Genetic deficiency of TREM2 caused significantly higher corticosterone levels at the early stage of LPS-induced septic shock; whereas TREM2 deficiency neither increased CRH and ACTH nor exacerbated the inflammation in adrenocortical tissue during septic shock. Ex vivo study revealed that Trem2-/- macrophages significantly promoted the expression of steroidogenic enzymes and increased production of corticosterone. Furthermore, Trem2-/- macrophage-derived exosomes were able to mimic Trem2-/- macrophages in enhancing adrenocortical steroidogenesis. CONCLUSIONS At the early stage of LPS-induced septic shock, corticosterone biosynthesis can be inhibited by macrophage TREM2 in adrenocortical cells, which might partially associate with macrophage-derived exosomes.
Collapse
Affiliation(s)
- Hui Ye
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Zhai
- Department of Anesthesiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ping Fang
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Department of Anesthesiology, Lihuili Hospital, Ningbo Medical Center, Ningbo, China
| | - Shiyue Yang
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yaqi Sun
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuijing Wu
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ruoqiong Huang
- Department of Clinical Research Center, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qixing Chen
- Department of Clinical Research Center, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiangming Fang
- Department of Anesthesiology and Intensive Care Unit, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| |
Collapse
|
20
|
Boeri L, Perottoni S, Izzo L, Giordano C, Albani D. Microbiota-Host Immunity Communication in Neurodegenerative Disorders: Bioengineering Challenges for In Vitro Modeling. Adv Healthc Mater 2021; 10:e2002043. [PMID: 33661580 DOI: 10.1002/adhm.202002043] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/01/2021] [Indexed: 12/12/2022]
Abstract
Human microbiota communicates with its host by secreting signaling metabolites, enzymes, or structural components. Its homeostasis strongly influences the modulation of human tissue barriers and immune system. Dysbiosis-induced peripheral immunity response can propagate bacterial and pro-inflammatory signals to the whole body, including the brain. This immune-mediated communication may contribute to several neurodegenerative disorders, as Alzheimer's disease. In fact, neurodegeneration is associated with dysbiosis and neuroinflammation. The interplay between the microbial communities and the brain is complex and bidirectional, and a great deal of interest is emerging to define the exact mechanisms. This review focuses on microbiota-immunity-central nervous system (CNS) communication and shows how gut and oral microbiota populations trigger immune cells, propagating inflammation from the periphery to the cerebral parenchyma, thus contributing to the onset and progression of neurodegeneration. Moreover, an overview of the technological challenges with in vitro modeling of the microbiota-immunity-CNS axis, offering interesting technological hints about the most advanced solutions and current technologies is provided.
Collapse
Affiliation(s)
- Lucia Boeri
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta” Politecnico di Milano Piazza Leonardo da Vinci 32 Milan 20133 Italy
| | - Simone Perottoni
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta” Politecnico di Milano Piazza Leonardo da Vinci 32 Milan 20133 Italy
| | - Luca Izzo
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta” Politecnico di Milano Piazza Leonardo da Vinci 32 Milan 20133 Italy
| | - Carmen Giordano
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta” Politecnico di Milano Piazza Leonardo da Vinci 32 Milan 20133 Italy
| | - Diego Albani
- Department of Neuroscience Istituto di Ricerche Farmacologiche Mario Negri IRCCS via Mario Negri 2 Milan 20156 Italy
| |
Collapse
|
21
|
TREM2, microglia, and Alzheimer's disease. Mech Ageing Dev 2021; 195:111438. [PMID: 33516818 DOI: 10.1016/j.mad.2021.111438] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/02/2021] [Accepted: 01/17/2021] [Indexed: 12/19/2022]
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) has been suggested to play a crucial role in Alzheimer's disease (AD) pathogenesis, as revealed by genome-wide association studies (GWAS). Since then, rapidly increasing literature related to TREM2 has focused on elucidating its role in AD pathology. In this review, we summarize our understanding of TREM2 biology, explore TREM2 functions in microglia, address the multiple mechanisms of TREM2 in AD, and raise key questions for further investigations to elucidate the detailed roles and molecular mechanisms of TREM2 in microglial responses. A major breakthrough in our understanding of TREM2 is based on our hypothesis suggesting that TREM2 may act as a multifaceted player in microglial functions in AD brain homeostasis. We conclude that TREM2 can not only influence microglial functions in amyloid and tau pathologies but also participate in inflammatory responses and metabolism, acting alone or with other molecules, such as apolipoprotein E (APOE). This review provides novel insight into the broad role of TREM2 in microglial function in AD and enables us to develop new strategies aimed at the immune system to treat AD pathogenesis.
Collapse
|
22
|
Cao BQ, Tan F, Zhan J, Lai PH. Mechanism underlying treatment of ischemic stroke using acupuncture: transmission and regulation. Neural Regen Res 2021; 16:944-954. [PMID: 33229734 PMCID: PMC8178780 DOI: 10.4103/1673-5374.297061] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The inflammatory response after cerebral ischemia/reperfusion is an important cause of neurological damage and repair. After cerebral ischemia/reperfusion, microglia are activated, and a large number of circulating inflammatory cells infiltrate the affected area. This leads to the secretion of inflammatory mediators and an inflammatory cascade that eventually causes secondary brain damage, including neuron necrosis, blood-brain barrier destruction, cerebral edema, and an oxidative stress response. Activation of inflammatory signaling pathways plays a key role in the pathological process of ischemic stroke. Increasing evidence suggests that acupuncture can reduce the inflammatory response after cerebral ischemia/reperfusion and promote repair of the injured nervous system. Acupuncture can not only inhibit the activation and infiltration of inflammatory cells, but can also regulate the expression of inflammation-related cytokines, balance the effects of pro-inflammatory and anti-inflammatory factors, and interfere with inflammatory signaling pathways. Therefore, it is important to study the transmission and regulatory mechanism of inflammatory signaling pathways after acupuncture treatment for cerebral ischemia/reperfusion injury to provide a theoretical basis for clinical treatment of this type of injury using acupuncture. Our review summarizes the overall conditions of inflammatory cells, mediators, and pathways after cerebral ischemia/reperfusion, and discusses the possible synergistic intervention of acupuncture in the inflammatory signaling pathway network to provide a foundation to explore the multiple molecular mechanisms by which acupuncture promotes nerve function restoration.
Collapse
Affiliation(s)
- Bing-Qian Cao
- Department of Neurology, Foshan Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Foshan, Guangdong Province, China
| | - Feng Tan
- Department of Neurology, Foshan Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Foshan, Guangdong Province, China
| | - Jie Zhan
- Department of Rehabilitation, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, Guangdong Province, China
| | - Peng-Hui Lai
- Department of Rehabilitation, Nan'ao People's Hospital Dapeng New District, Shenzhen, Guangdong Province, China
| |
Collapse
|
23
|
Sun H, Feng J, Tang L. Function of TREM1 and TREM2 in Liver-Related Diseases. Cells 2020; 9:2626. [PMID: 33297569 PMCID: PMC7762355 DOI: 10.3390/cells9122626] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023] Open
Abstract
TREM1 and TREM2 are members of the triggering receptors expressed on myeloid cells (TREM) family. Both TREM1 and TREM2 are immunoglobulin superfamily receptors. Their main function is to identify foreign antigens and toxic substances, thereby adjusting the inflammatory response. In the liver, TREM1 and TREM2 are expressed on non-parenchymal cells, such as liver sinusoidal endothelial cells, Kupffer cells, and hepatic stellate cells, and cells which infiltrate the liver in response to injury including monocyte-derived macrophages and neutrophils. The function of TREM1 and TREM2 in inflammatory response depends on Toll-like receptor 4. TREM1 mainly augments inflammation during acute inflammation, while TREM2 mainly inhibits chronic inflammation to protect the liver from pathological changes. Chronic inflammation often induces metabolic abnormalities, fibrosis, and tumorigenesis. The above physiological changes lead to liver-related diseases, such as liver injury, nonalcoholic steatohepatitis, hepatic fibrosis, and hepatocellular carcinoma. Here, we review the function of TREM1 and TREM2 in different liver diseases based on inflammation, providing a more comprehensive perspective for the treatment of liver-related diseases.
Collapse
Affiliation(s)
- Huifang Sun
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China;
| | - Jianguo Feng
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China
| | - Liling Tang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China;
| |
Collapse
|
24
|
Lei L, Chai Y, Lin H, Chen C, Zhao M, Xiong W, Zhuang J, Fan X. Dihydroquercetin Activates AMPK/Nrf2/HO-1 Signaling in Macrophages and Attenuates Inflammation in LPS-Induced Endotoxemic Mice. Front Pharmacol 2020; 11:662. [PMID: 32508636 PMCID: PMC7248193 DOI: 10.3389/fphar.2020.00662] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/23/2020] [Indexed: 12/19/2022] Open
Abstract
Dihydroquercetin (DHQ) is a flavonoid compound known for its anti-oxidant effects. Oxidative stress plays a dominant role in regulating the pathways associated with systemic inflammatory immune activation during endotoxemia. Whether and how DHQ regulates inflammatory responses in endotoxemia remains elusive. Here we show DHQ pretreatment effectively reduced the Ten-day mortality in bacterial endotoxin lipopolyssacharide (LPS)-challenged mice, suppressing LPS-induced inflammatory responses reflected by impaired production of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in the serum of mice. In Raw 264.7 cells, DHQ pretreatment significantly inhibited the transcriptional upregulation of TNF-α, interferon-γ (IFN-γ), interleukin-10 (IL-10) and toll-like receptor 4 (TLR-4) after LPS stimulation. Additionally, knockdown of heme oxygenase-1 (HO-1), one of the most important DHQ induced antioxidant genes, cancelled the inhibition of DHQ treatment on LPS induced TNF-α, IFN-γ production. Nuclear factor erythroid 2-related factor 2 (Nrf2) expression and AMP-activated protein kinase (AMPK) phosphorylation were both enhanced by DHQ in Raw 264.7 cells, indicating a DHQ induced AMPK/Nrf2/HO-1 signal axis. In conclusion, DHQ pretreatment could protect mice against the inflammation and mortality associated with endotoxemia.
Collapse
Affiliation(s)
- Liming Lei
- Department of Intensive Care Unit of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Laboratory of South China Structural Heart Disease, Guangzhou, China
| | - Yunfei Chai
- Department of Anesthesiology of Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Haoming Lin
- Department of Hepatobiliary Pancreatic Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Chunbo Chen
- Department of Intensive Care Unit of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Laboratory of South China Structural Heart Disease, Guangzhou, China
| | - Mingyi Zhao
- Department of Pediatrics, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Weiping Xiong
- Department of Intensive Care Unit of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Laboratory of South China Structural Heart Disease, Guangzhou, China
| | - Jian Zhuang
- Department of Cardiovascular Surgery of Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Laboratory of South China Structural Heart Disease, Guangzhou, China
| | - Xiaoping Fan
- Department of Cardiovascular Surgery of Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Laboratory of South China Structural Heart Disease, Guangzhou, China
| |
Collapse
|
25
|
The Emerging Role of Curcumin in the Modulation of TLR-4 Signaling Pathway: Focus on Neuroprotective and Anti-Rheumatic Properties. Int J Mol Sci 2020; 21:ijms21072299. [PMID: 32225104 PMCID: PMC7177421 DOI: 10.3390/ijms21072299] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/25/2020] [Accepted: 03/24/2020] [Indexed: 12/20/2022] Open
Abstract
Natural products have been used in medicine for thousands of years. Given their potential health benefits, they have gained significant popularity in recent times. The administration of phytochemicals existed shown to regulate differential gene expression and modulate various cellular pathways implicated in cell protection. Curcumin is a natural dietary polyphenol extracted from Curcuma Longa Linn with different biological and pharmacological effects. One of the important targets of curcumin is Toll-like receptor-4 (TLR-4), the receptor which plays a key role in the modulation of the immune responses and the stimulation of inflammatory chemokines and cytokines production. Different studies have demonstrated that curcumin attenuates inflammatory response via TLR-4 acting directly on receptor, or by its downstream pathway. Curcumin bioavailability is low, so the use of exosomes, as nano drug delivery, could improve the efficacy of curcumin in inflammatory diseases. The focus of this review is to explore the therapeutic effect of curcumin interacting with TLR-4 receptor and how this modulation could improve the prognosis of neuroinflammatory and rheumatic diseases.
Collapse
|
26
|
Bandow K, Hasegawa H, Tomomura M, Tomomura A. Caldecrin inhibits lipopolysaccharide-induced pro-inflammatory cytokines and M1 macrophage polarization through the immunoreceptor triggering receptor expressed in myeloid cells-2. Biochem Biophys Res Commun 2020; 523:1027-1033. [PMID: 31973822 DOI: 10.1016/j.bbrc.2020.01.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/08/2020] [Indexed: 12/14/2022]
Abstract
Caldecrin was previously isolated as a serum calcium-decreasing factor from the pancreas and is known to suppress receptor activator of nuclear factor-κB ligand (RANKL)-induced calcium oscillation pathways in osteoclasts. Here, we explored the effects of caldecrin on lipopolysaccharide (LPS)-Toll-like receptor-4 (TLR-4) signaling pathways in macrophages. Caldecrin inhibited the LPS-induced gene expression of pro-inflammatory cytokines and M1 macrophage polarization in mouse bone marrow macrophages and the RAW264.7 mouse macrophage cell line. Next, we focused on triggering receptor expressed in myeloid cells-2 (TREM-2) as a co-receptor common to RANKL receptor and TLR-4, and established Trem2-KO RAW264.7 cells, in which Trem2 gene was deleted using the CRISPR/Cas9 system. Caldecrin-mediated alterations in pro-inflammatory cytokine expression and M1 macrophage polarization were not observed in Trem2-KO RAW264.7 cells. These results suggest that caldecrin is not only an inhibitor of osteoclast activation but also a negative regulator of LPS-induced inflammatory responses, functioning via TREM-2.
Collapse
Affiliation(s)
- Kenjiro Bandow
- Division of Biochemistry, Department of Oral Biology and Tissue Engineering, 1-1 Keyakidai, Sakado, Saitama, 350-0283, Japan
| | - Hiroya Hasegawa
- Division of Orthodontics, Department of Human Development and Fostering, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama, 350-0283, Japan
| | - Mineko Tomomura
- Division of Biochemistry, Department of Oral Biology and Tissue Engineering, 1-1 Keyakidai, Sakado, Saitama, 350-0283, Japan; Department of Oral Health Sciences, Meikai University School of Health Sciences, 1 Akemi, Urayasu, Chiba, 279-8550, Japan
| | - Akito Tomomura
- Division of Biochemistry, Department of Oral Biology and Tissue Engineering, 1-1 Keyakidai, Sakado, Saitama, 350-0283, Japan.
| |
Collapse
|
27
|
Singh AK, Mishra G, Maurya A, Awasthi R, Kumari K, Thakur A, Rai A, Rai GK, Sharma B, Kulkarni GT, Singh SK. Role of TREM2 in Alzheimer's Disease and its Consequences on β- Amyloid, Tau and Neurofibrillary Tangles. Curr Alzheimer Res 2020; 16:1216-1229. [DOI: 10.2174/1567205016666190903102822] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/21/2019] [Accepted: 08/21/2019] [Indexed: 11/22/2022]
Abstract
:
Alzheimer's Disease (AD) is age-related neurodegenerative disorder recognized by a steadily
gradual cognitive decline that has devastating personal and socioeconomic implications. Recently, some
genetic factors for AD have been identified which attracted wide attention of researchers in different
areas of AD biology and possible new therapeutic targets. Alternative forms of triggering receptor expressed
on myeloid cells 2 (TREM2) genes are examples of such risk factors, which contribute higher
risk for developing AD. Comprehending TREM2 function pledge to provide salient insight into how
neuroinflammation contributes to AD pathology. The dearth of microglial TREM2 shepherd to augmented
tau pathology is couple with frequent enhancement of activated neuronal stress kinases. The involvement
of TREM2 in the regulation of tau-associated innate immune response of the CNS has clearly
demonstrated through these findings. However, whether decrease level of TREM2 assists pathology of
tau through changed clearance and pathological escalation of tau or through direct contact between microglia
and neuron and any alternative possible mechanisms need to examine. This review briefly summarizes
distinct functional roles of TREM2 in AD pathology and highlights the TREM2 gene regulation.
We have also addressed the impact of TREM2 on β-amyloid plaques and tau pathology in Alzheimer’s
disease.
Collapse
Affiliation(s)
- Anurag K. Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Gaurav Mishra
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Anand Maurya
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Rajendra Awasthi
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Komal Kumari
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Abhimanyu Thakur
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Arati Rai
- Hygia Institute of Pharmaceutical Education & Research, Lucknow-226020, Uttar Pradesh, India
| | - Gopal Kumar Rai
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi- 221005, Uttar Pradesh, India
| | - Bhupesh Sharma
- Department of Pharmacology, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Giriraj T Kulkarni
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Santosh Kumar Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| |
Collapse
|
28
|
Zhang J, Zheng Y, Luo Y, Du Y, Zhang X, Fu J. Curcumin inhibits LPS-induced neuroinflammation by promoting microglial M2 polarization via TREM2/ TLR4/ NF-κB pathways in BV2 cells. Mol Immunol 2019; 116:29-37. [PMID: 31590042 DOI: 10.1016/j.molimm.2019.09.020] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/16/2019] [Accepted: 09/26/2019] [Indexed: 12/13/2022]
Abstract
Microglia mediate multiple facets of neuroinflammation, which plays a double-edged role in various brain diseases via distinct microglial phenotypes (deleterious M1 and neuroprotective M2). Therefore, the inhibition of overactivated inflammatory M1 microglia by switching to the protective M2 phenotype appears to be a potential therapeutic strategy in neuroinflammatory disorders. Curcumin has been shown to exhibit anti-inflammatory and neuroprotective activities. The present study investigated the potential effects of curcumin on microglial M1/M2 polarization and elucidated the possible molecular mechanisms of action in vitro. In this study, the BV2 microglial cell line was pretreated with different curcumin concentrations in the presence or absence of lipopolysaccharide (LPS) to assess the anti-inflammatory efficacy of curcumin based on the morphological and inflammatory changes. The cytotoxicity of curcumin for BV2 cells was evaluated using the CCK-8 assay. Further, the effect of curcumin concentrations on LPS-induced BV2 cells was studied. The morphological changes were observed using an optical microscope and immunofluorescent staining. Nitric oxide (NO) expression was determined using the Griess reagent. The expression of cytokines and inflammatory mediators was also measured by ELISA, qRT-PCR, flow cytometry, and immunofluorescence. Western blot analysis was used to determine the levels of triggering receptor expressed on myeloid cells 2 (TREM2), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) p65, p-NF-κB p65, IκB, and p-IκB expression. Results showed that curcumin concentrations less than 10 μM did not induce any detectable cytotoxicity but decreased BV2 cell viability up to 20 μM. Curcumin inhibited LPS-induced microglial activation. Curcumin treatment switched the M1 pro-inflammatory phenotype to the M2 anti-inflammatory phenotype by decreasing the expression of M1 markers (i.e., iNOS, IL-1β, IL-6, and CD16/32) and elevating the expression of M2 markers (i.e., arginase 1, IL-4, IL-10, and CD206). Interestingly, curcumin attenuated the activation of TLR4/NF-κB pathways and the downregulation of TREM2 expression in LPS-activated BV2 cells. Collectively, these results suggest that curcumin significantly alleviates LPS-induced inflammation by regulating microglial (M1/M2) polarization by reducing the imbalance of TREM2 and TLR4 and balancing the downstream NF-κB activation.
Collapse
Affiliation(s)
- Jiawei Zhang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China
| | - Yaling Zheng
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China
| | - Yan Luo
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China
| | - Yu Du
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China
| | - Xiaojie Zhang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China
| | - Jianliang Fu
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China.
| |
Collapse
|
29
|
D'Argenio V, Sarnataro D. Microbiome Influence in the Pathogenesis of Prion and Alzheimer's Diseases. Int J Mol Sci 2019; 20:E4704. [PMID: 31547531 PMCID: PMC6801937 DOI: 10.3390/ijms20194704] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/20/2019] [Accepted: 09/21/2019] [Indexed: 12/14/2022] Open
Abstract
Misfolded and abnormal β-sheets forms of wild-type proteins, such as cellular prion protein (PrPC) and amyloid beta (Aβ), are believed to be the vectors of neurodegenerative diseases, prion and Alzheimer's disease (AD), respectively. Increasing evidence highlights the "prion-like" seeding of protein aggregates as a mechanism for pathological spread in AD, tauopathy, as well as in other neurodegenerative diseases, such as Parkinson's. Mutations in both PrPC and Aβ precursor protein (APP), have been associated with the pathogenesis of these fatal disorders with clear evidence for their pathogenic significance. In addition, a critical role for the gut microbiota is emerging; indeed, as a consequence of gut-brain axis alterations, the gut microbiota has been involved in the regulation of Aβ production in AD and, through the microglial inflammation, in the amyloid fibril formation, in prion diseases. Here, we aim to review the role of microbiome ("the other human genome") alterations in AD and prion disease pathogenesis.
Collapse
Affiliation(s)
- Valeria D'Argenio
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, via Pansini 5, 80131 Naples, Italy.
- CEINGE-Biotecnologie Avanzate, via G. Salvatore 486, 80145 Naples, Italy.
- Task Force on Microbiome Studies, University of Naples Federico II, 80131 Naples, Italy.
| | - Daniela Sarnataro
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, via Pansini 5, 80131 Naples, Italy.
- CEINGE-Biotecnologie Avanzate, via G. Salvatore 486, 80145 Naples, Italy.
| |
Collapse
|
30
|
Guo Y, Wei X, Yan H, Qin Y, Yan S, Liu J, Zhao Y, Jiang F, Lou H. TREM2 deficiency aggravates α-synuclein-induced neurodegeneration and neuroinflammation in Parkinson's disease models. FASEB J 2019; 33:12164-12174. [PMID: 31370707 DOI: 10.1096/fj.201900992r] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Variants in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) are known to increase the risk of developing Alzheimer disease and Parkinson's disease (PD). However, the potential role of TREM2 effect on synucleinopathy has not been characterized. In this study, we investigated whether loss of TREM2 function affects α-synucleinopathy both in vitro and in vivo. In vitro, BV2 microglial cells were exposed to α-synuclein (α-syn) in the presence or absence of TREM2 small interference RNA. For in vivo studies, wild-type controls and TREM2 gene knockout mice were intracranially injected in the substantia nigra with adeno-associated viral vectors expressing human α-syn (AAV-SYN) to induce PD. Our results revealed that knockdown of TREM2 aggravated α-syn-induced inflammatory responses in BV2 cells and caused greater apoptosis in SH-SY5Y cells treated with BV2-conditioned medium. In mice, TREM2 knockout exacerbated dopaminergic neuron loss in response to AAV-SYN. Moreover, both in vitro and in vivo TREM2 deficiency induced a shift from an anti-inflammatory toward a proinflammatory activation status of microglia. These data suggest that impairing microglial TREM2 signaling aggravates proinflammatory responses to α-syn and exacerbates α-syn-induced neurodegeneration by modulating microglial activation state.-Guo, Y., Wei, X., Yan, H., Qin, Y., Yan, S., Liu, J., Zhao, Y., Jiang, F., Lou, H. TREM2 deficiency aggravates α-synuclein-induced neurodegeneration and neuroinflammation in Parkinson's disease models.
Collapse
Affiliation(s)
- Ying Guo
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Xinbing Wei
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Hua Yan
- Department of Gastroenterology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yue Qin
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Shaoqi Yan
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Jia Liu
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Yong Zhao
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| | - Fan Jiang
- Department of Pathophysiology, School of Medicine, Shandong University, Jinan, China
| | - Haiyan Lou
- Department of Pharmacology, School of Medicine, Shandong University, Jinan, China
| |
Collapse
|
31
|
Imbalance of Microglial TLR4/TREM2 in LPS-Treated APP/PS1 Transgenic Mice: A Potential Link Between Alzheimer's Disease and Systemic Inflammation. Neurochem Res 2019; 44:1138-1151. [PMID: 30756214 DOI: 10.1007/s11064-019-02748-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023]
Abstract
Clinically, superimposed systemic inflammation generally has significant deleterious effects on the Alzheimer's disease (AD) progression. However, the related molecular mechanisms remain poorly understood. Microglial toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells 2 (TREM2) are two key regulators of inflammation that may play an essential role in this complex pathophysiological process. In this study, intraperitoneal injection of lipopolysaccharide (LPS) into APP/PS1 transgenic AD model was used to mimic systemic inflammation in the development of AD. Initial results from the cortex showed that compared with wild-type mice, APP/PS1 mice exhibited elevated gene and protein expression levels of both TLR4 and TREM2 with different degree. Interestingly, after LPS treatment, TLR4 expression was persistently up-regulated, while TREM2 expression was significantly down-regulated in APP/PS1 mice, suggesting that the negative regulatory effect of TREM2 on inflammation might be suppressed by LPS-induced hyperactive TLR4. This imbalance of TLR4/TREM2 contributed to microglial over-activation, followed by increased neuronal apoptosis in the cortex of APP/PS1 mice; these changes did not alter the expression level of Aβ1-42. Similar alterations were observed in our in vitro experiment with β-amyloid1-42 (Aβ1-42)-treated N9 microglia. Further, Morris water maze (MWM) testing data indicated that LPS administration acutely aggravated cognitive impairment in APP/PS1 mice, suggesting that the addition of systemic inflammation can potentially accelerate the progression of AD. Collectively, we conclude that an imbalance of TLR4/TREM2 may be a potential link between AD and systemic inflammation. TREM2 can serve as a potential therapeutic target for treating systemic inflammation in AD progression.
Collapse
|
32
|
Gratuze M, Leyns CEG, Holtzman DM. New insights into the role of TREM2 in Alzheimer's disease. Mol Neurodegener 2018; 13:66. [PMID: 30572908 PMCID: PMC6302500 DOI: 10.1186/s13024-018-0298-9] [Citation(s) in RCA: 286] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 11/28/2018] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia. The two histopathological markers of AD are amyloid plaques composed of the amyloid-β (Aβ) peptide, and neurofibrillary tangles of aggregated, abnormally hyperphosphorylated tau protein. The majority of AD cases are late-onset, after the age of 65, where a clear cause is still unknown. However, there are likely different multifactorial contributors including age, enviornment, biology and genetics which can increase risk for the disease. Genetic predisposition is considerable, with heritability estimates of 60-80%. Genetic factors such as rare variants of TREM2 (triggering receptor expressed on myeloid cells-2) strongly increase the risk of developing AD, confirming the role of microglia in AD pathogenesis. In the last 5 years, several studies have dissected the mechanisms by which TREM2, as well as its rare variants affect amyloid and tau pathologies and their consequences in both animal models and in human studies. In this review, we summarize increases in our understanding of the involvement of TREM2 and microglia in AD development that may open new therapeutic strategies targeting the immune system to influence AD pathogenesis.
Collapse
Affiliation(s)
- Maud Gratuze
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Cheryl E. G. Leyns
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - David M. Holtzman
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| |
Collapse
|
33
|
Francis IP, Islam EA, Gower AC, Shaik-Dasthagirisaheb YB, Gray-Owen SD, Wetzler LM. Murine host response to Neisseria gonorrhoeae upper genital tract infection reveals a common transcriptional signature, plus distinct inflammatory responses that vary between reproductive cycle phases. BMC Genomics 2018; 19:627. [PMID: 30134832 PMCID: PMC6106831 DOI: 10.1186/s12864-018-5000-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/08/2018] [Indexed: 01/13/2023] Open
Abstract
Background The emergence of fully antimicrobial resistant Neisseria gonorrhoeae has led global public health agencies to identify a critical need for next generation anti-gonococcal pharmaceuticals. The development and success of these compounds will rely upon valid pre-clinical models of gonorrhoeae infection. We recently developed and reported the first model of upper genital tract gonococcal infection. During initial characterization, we observed significant reproductive cycle-based variation in infection outcome. When uterine infection occurred in the diestrus phase, there was significantly greater pathology than during estrus phase. The aim of this study was to evaluate transcriptional profiles of infected uterine tissue from mice in either estrus or diestrus phase in order to elucidate possible mechanisms for these differences. Results Genes and biological pathways with phase-independent induction during infection showed a chemokine dominant cytokine response to Neisseria gonorrhoeae. Despite general induction being phase-independent, this common anti-gonococcal response demonstrated greater induction during diestrus phase infection. Greater activity of granulocyte adhesion and diapedesis regulators during diestrus infection, particularly in chemokines and diapedesis regulators, was also shown. In addition to a greater induction of the common anti-gonococcal response, Gene Set Enrichment Analysis identified a diestrus-specific induction of type-1 interferon signaling pathways. Conclusions This transcriptional analysis of murine uterine gonococcal infection during distinct points in the natural reproductive cycle provided evidence for a common anti-gonococcal response characterized by significant induction of granulocyte chemokine expression and high proinflammatory mediators. The basic biology of this host response to N. gonorrhoeae in estrus and diestrus is similar at the pathway level but varies drastically in magnitude. Overlaying this, we observed type-1 interferon induction specifically in diestrus infection where greater pathology is observed. This supports recent work suggesting this pathway has a significant, possibly host-detrimental, function in gonococcal infection. Together these findings lay the groundwork for further examination of the role of interferons in gonococcal infection. Additionally, this work enables the implementation of the diestrus uterine infection model using the newly characterized host response as a marker of pathology and its prevention as a correlate of candidate vaccine efficacy and ability to protect against the devastating consequences of N. gonorrhoeae-associated sequelae. Electronic supplementary material The online version of this article (10.1186/s12864-018-5000-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ian P Francis
- Department of Microbiology, Boston University School of Medicine, 72 E. Concord St., Room L504, Boston, MA, 02118, USA
| | - Epshita A Islam
- Department of Molecular Genetics, University of Toronto, Room 4383, Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Adam C Gower
- Clinical and Translational Science Institute, Boston University School of Medicine, 715 Albany St. E-727, Boston, MA, 02118, USA
| | | | - Scott D Gray-Owen
- Department of Molecular Genetics, University of Toronto, Room 4383, Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Lee M Wetzler
- Department of Medicine, Boston University School of Medicine, 715 Albany St. E-113, Boston, MA, 02118, USA. .,Department of Microbiology, Boston University School of Medicine, 72 E. Concord St., Room L504, Boston, MA, 02118, USA.
| |
Collapse
|
34
|
Spielman LJ, Gibson DL, Klegeris A. Unhealthy gut, unhealthy brain: The role of the intestinal microbiota in neurodegenerative diseases. Neurochem Int 2018; 120:149-163. [PMID: 30114473 DOI: 10.1016/j.neuint.2018.08.005] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 02/08/2023]
Abstract
The number of bacterial cells living within the human body is approximately equal to, or greater than, the total number of human cells. This dynamic population of microorganisms, termed the human microbiota, resides mainly within the gastrointestinal tract. It is widely accepted that highly diverse and stable microbiota promote overall human health. Colonization of the gut with maladaptive and pathogenic microbiota, a state also known as dysbiosis, is associated with a variety of peripheral diseases ranging from type 2 diabetes mellitus to cardiovascular and inflammatory bowel disease. More recently, microbial dysbiosis has been associated with a number of brain pathologies, including autism spectrum disorder, Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), suggesting a direct or indirect communication between intestinal bacteria and the central nervous system (CNS). In this review, we illustrate two pathways implicated in the crosstalk between gut microbiota and CNS involving 1) the vagus nerve and 2) transmission of signaling molecules through the circulatory system and across the blood-brain barrier (BBB). We summarize the available evidence of the specific changes in the intestinal microbiota, as well as microorganism-induced modifications to intestinal and BBB permeability, which have been linked to several neurodegenerative disorders including ALS, AD, and PD. Even though each of these diseases arises from unique pathogenetic mechanisms, all are characterized, at least in part, by chronic neuroinflammation. We provide an interpretation for the substantial evidence that healthy intestinal microbiota have the ability to positively regulate the neuroimmune responses in the CNS. Even though the evidence is mainly associative, it has been suggested that bacterial dysbiosis could contribute to an adverse neuroinflammatory state leading to increased risk of neurodegenerative diseases. Thus, developing strategies for regulating and maintaining healthy intestinal microbiota could be a valid approach for lowering individual risk and prevalence of neurodegenerative diseases.
Collapse
Affiliation(s)
| | - Deanna Lynn Gibson
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, Canada
| |
Collapse
|
35
|
Li C, Zhao B, Lin C, Gong Z, An X. TREM2 inhibits inflammatory responses in mouse microglia by suppressing the PI3K/NF-κB signaling. Cell Biol Int 2018; 43:360-372. [PMID: 29663649 PMCID: PMC7379930 DOI: 10.1002/cbin.10975] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/21/2018] [Indexed: 12/26/2022]
Abstract
This study aimed to investigate the effects of triggering receptor expressed on myeloid cell‐2 (TREM2) on the production of pro‐inflammatory mediators and cytokines induced by lipopolysaccharide (LPS) in BV2 microglia. TREM2 expression or TREM2‐specific siRNA were used to induce TREM2 overexpression or silencing. The BV2 cells were pre‐treated with the PI3 K inhibitor of LY294002 for 1 h and stimulated with LPS for 24 h. Then, the cell viability, apoptosis, phagocytosis, nitric oxide (NO), lactate dehydrogenase (LDH), and cytokine production, as well as the activation of AKT and NF‐kB were determined, respectively. We found LPS stimulation significantly reduced BV2 cell viability, enhanced BV2 cell phagocytosis and apoptosis compared to the control groups. In addition, LPS stimulation significantly increased the production of NO, LDH, TNF‐α, IL‐1β, and the activation of AKT and NF‐kB, while decreased the levels of IL‐10 and TGF‐β1. However, these pro‐inflammatory effects were significantly attenuated by TREM2 overexpression or pre‐treatment with LY294002, while enhanced by TREM2 silencing. Thus, we concluded that TREM2 inhibited neuroinflammation by down‐regulating PI3 K/AKT and NF‐kB signaling in BV2 microglia. Above all, therapeutic enhanced TREM2 expression may be a new strategy for intervention of neuroinflammatory diseases.
Collapse
Affiliation(s)
- Caixia Li
- Department of Anesthesiology, The First Affiliated Hospital, School of MedicineZhejiang UniversityHangzhouP. R. China
- Department of Anesthesiology, The Fourth Affiliated Hospital, School of MedicineZhejiang UniversityYiwuP. R. China
| | - Bing Zhao
- Department of Anesthesiology, The First Affiliated Hospital, School of MedicineZhejiang UniversityHangzhouP. R. China
| | - Caizhao Lin
- Department of Anesthesiology, The First Affiliated Hospital, School of MedicineZhejiang UniversityHangzhouP. R. China
| | - Zhiping Gong
- Department of Anesthesiology, The Fourth Affiliated Hospital, School of MedicineZhejiang UniversityYiwuP. R. China
| | - Xiaoxia An
- Department of Anesthesiology, The First Affiliated Hospital, School of MedicineZhejiang UniversityHangzhouP. R. China
| |
Collapse
|
36
|
Kang SS, Kurti A, Baker KE, Liu CC, Colonna M, Ulrich JD, Holtzman DM, Bu G, Fryer JD. Behavioral and transcriptomic analysis of Trem2-null mice: not all knockout mice are created equal. Hum Mol Genet 2018; 27:211-223. [PMID: 29040522 PMCID: PMC5886290 DOI: 10.1093/hmg/ddx366] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/31/2017] [Accepted: 09/21/2017] [Indexed: 01/08/2023] Open
Abstract
It is clear that innate immune system status is altered in numerous neurodegenerative diseases. Human genetic studies have demonstrated that triggering receptor expressed in myeloid cells 2 (TREM2) coding variants have a strong association with Alzheimer's disease (AD) and other neurodegenerative diseases. To more thoroughly understand the impact of TREM2 in vivo, we studied the behavioral and cognitive functions of wild-type (WT) and Trem2-/- (KO) mice during basal conditions and brain function in the context of innate immune stimulation with peripherally administered lipopolysaccharide (LPS). Early markers of neuroinflammation preceded Aif1 and Trem2 upregulation that occurred at later stages (24-48 h post-LPS). We performed a transcriptomic study of these cohorts and found numerous transcripts and pathways that were altered in Trem2-/- mice both at baseline and 48 h after LPS challenge. Importantly, our transcriptome analysis revealed that our Trem2-/- mouse line (Velocigene allele) results in exaggerated Treml1 upregulation. In contrast, aberrantly high Treml1 expression was absent in the Trem2 knockout line generated by the Colonna lab and the Jackson Labs CRISPR/Cas9 Trem2 knockout line. Notably, removal of the floxed neomycin selection cassette ameliorated aberrant Treml1 expression, validating the artifactual nature of Treml1 expression in the original Trem2-/- Velocigene line. Clearly further studies are needed to decipher whether the Treml1 transcriptional artifact is functionally meaningful, but our data indicate that caution is warranted when interpreting functional studies with this particular line. Additionally, our results indicate that other Velocigene alleles or targeting strategies with strong heterologous promoters need to carefully consider downstream genes.
Collapse
Affiliation(s)
- Silvia S Kang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Aishe Kurti
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Kelsey E Baker
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Jason D Ulrich
- Department of Neurology, Washington University, St. Louis, MO 63110, USA
| | - David M Holtzman
- Department of Neurology, Washington University, St. Louis, MO 63110, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| |
Collapse
|
37
|
Increased TREM-2 expression on the subsets of CD11c + cells in the lungs and lymph nodes during allergic airway inflammation. Sci Rep 2017; 7:11853. [PMID: 28928485 PMCID: PMC5605689 DOI: 10.1038/s41598-017-12330-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/07/2017] [Indexed: 11/29/2022] Open
Abstract
Dendritic cells (DCs) are professional APCs that traffic to the draining lymph nodes where they present processed antigens to naïve T-cells. The recently discovered triggering receptor expressed on myeloid cells (TREM)-2 has been shown to be expressed on DCs in several disease models, however, its role in asthma is yet to be elucidated. In the present study, we examined the effect of allergen exposure on TREM-2 expression in the airways and on DC subsets in the lung and lymph nodes in murine model of allergic airway inflammation. Sensitization and challenge with ovalbumin reproduced hallmark features of asthma. TREM-2 mRNA expression in the whole lung was significantly higher in the OVA-sensitized and -challenged mice which was associated with increased protein expression in the lungs. Analysis of CD11c+MHC-IIhi DCs in the lung and draining lymph nodes revealed that allergen exposure increased TREM-2 expression on all DC subsets with significantly higher expression in the lymph nodes. This was associated with increased mRNA expression of Th2 and Th17 cytokines. Further analyses showed that these TREM-2+ cells expressed high levels of CCR-7 and CD86 suggesting a potential role of TREM-2 in mediating maturation and migration of DC subsets in allergic airway inflammation.
Collapse
|
38
|
The lipid-sensor TREM2 aggravates disease in a model of LCMV-induced hepatitis. Sci Rep 2017; 7:11289. [PMID: 28900132 PMCID: PMC5595927 DOI: 10.1038/s41598-017-10637-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 08/14/2017] [Indexed: 12/20/2022] Open
Abstract
Lipid metabolism is increasingly being appreciated to affect immunoregulation, inflammation and pathology. In this study we found that mice infected with lymphocytic choriomeningitis virus (LCMV) exhibit global perturbations of circulating serum lipids. Mice lacking the lipid-sensing surface receptor triggering receptor expressed on myeloid cells 2 (Trem2 -/-) were protected from LCMV-induced hepatitis and showed improved virus control despite comparable virus-specific T cell responses. Non-hematopoietic expression of TREM2 was found to be responsible for aggravated hepatitis, indicating a novel role for TREM2 in the non-myeloid compartment. These results suggest a link between virus-perturbed lipids and TREM2 that modulates liver pathogenesis upon viral infection. Targeted interventions of this immunoregulatory axis may ameliorate tissue pathology in hepatitis.
Collapse
|
39
|
Jay TR, von Saucken VE, Landreth GE. TREM2 in Neurodegenerative Diseases. Mol Neurodegener 2017; 12:56. [PMID: 28768545 PMCID: PMC5541421 DOI: 10.1186/s13024-017-0197-5] [Citation(s) in RCA: 256] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
TREM2 variants have been identified as risk factors for Alzheimer's disease (AD) and other neurodegenerative diseases (NDDs). Because TREM2 encodes a receptor exclusively expressed on immune cells, identification of these variants conclusively demonstrates that the immune response can play an active role in the pathogenesis of NDDs. These TREM2 variants also confer the highest risk for developing Alzheimer's disease of any risk factor identified in nearly two decades, suggesting that understanding more about TREM2 function could provide key insights into NDD pathology and provide avenues for novel immune-related NDD biomarkers and therapeutics. The expression, signaling and function of TREM2 in NDDs have been extensively investigated in an effort to understand the role of immune function in disease pathogenesis and progression. We provide a comprehensive review of our current understanding of TREM2 biology, including new insights into the regulation of TREM2 expression, and TREM2 signaling and function across NDDs. While many open questions remain, the current body of literature provides clarity on several issues. While it is still often cited that TREM2 expression is decreased by pro-inflammatory stimuli, it is now clear that this is true in vitro, but inflammatory stimuli in vivo almost universally increase TREM2 expression. Likewise, while TREM2 function is classically described as promoting an anti-inflammatory phenotype, more than half of published studies demonstrate a pro-inflammatory role for TREM2, suggesting that its role in inflammation is much more complex. Finally, these components of TREM2 biology are applied to a discussion of how TREM2 impacts NDD pathologies and the latest assessment of how these findings might be applied to immune-directed clinical biomarkers and therapeutics.
Collapse
Affiliation(s)
- Taylor R. Jay
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
| | - Victoria E. von Saucken
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
| | - Gary E. Landreth
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
| |
Collapse
|
40
|
Yeh FL, Hansen DV, Sheng M. TREM2, Microglia, and Neurodegenerative Diseases. Trends Mol Med 2017; 23:512-533. [DOI: 10.1016/j.molmed.2017.03.008] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 02/15/2017] [Accepted: 03/26/2017] [Indexed: 01/17/2023]
|
41
|
Kober DL, Brett TJ. TREM2-Ligand Interactions in Health and Disease. J Mol Biol 2017; 429:1607-1629. [PMID: 28432014 DOI: 10.1016/j.jmb.2017.04.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 01/04/2023]
Abstract
The protein triggering receptor expressed on myeloid cells-2 (TREM2) is an immunomodulatory receptor with a central role in myeloid cell activation and survival. In recent years, the importance of TREM2 has been highlighted by the identification of coding variants that increase risk for Alzheimer's disease and other neurodegenerative diseases. Animal studies have further shown the importance of TREM2 in neurodegenerative and other inflammatory disease models including chronic obstructive pulmonary disease, multiple sclerosis, and stroke. A mechanistic understanding of TREM2 function remains elusive, however, due in part to the absence of conclusive information regarding the identity of endogenous TREM2 ligands. While many TREM2 ligands have been proposed, their physiological role and mechanism of engagement remain to be determined. In this review, we highlight the suggested roles of TREM2 in these diseases and the recent advances in our understanding of TREM2 and discuss putative TREM2-ligand interactions and their potential roles in signaling during health and disease. We develop a model based on the TREM2 structure to explain how different TREM2 ligands might interact with the receptor and how disease risk variants may alter ligand interactions. Finally, we propose future experimental directions to establish the role and importance of these different interactions on TREM2 function.
Collapse
Affiliation(s)
- Daniel L Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tom J Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
42
|
Heme drives hemolysis-induced susceptibility to infection via disruption of phagocyte functions. Nat Immunol 2016; 17:1361-1372. [PMID: 27798618 DOI: 10.1038/ni.3590] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/28/2016] [Indexed: 12/15/2022]
Abstract
Hemolysis drives susceptibility to bacterial infections and predicts poor outcome from sepsis. These detrimental effects are commonly considered to be a consequence of heme-iron serving as a nutrient for bacteria. We employed a Gram-negative sepsis model and found that elevated heme levels impaired the control of bacterial proliferation independently of heme-iron acquisition by pathogens. Heme strongly inhibited phagocytosis and the migration of human and mouse phagocytes by disrupting actin cytoskeletal dynamics via activation of the GTP-binding Rho family protein Cdc42 by the guanine nucleotide exchange factor DOCK8. A chemical screening approach revealed that quinine effectively prevented heme effects on the cytoskeleton, restored phagocytosis and improved survival in sepsis. These mechanistic insights provide potential therapeutic targets for patients with sepsis or hemolytic disorders.
Collapse
|
43
|
Morioka S, Nigorikawa K, Sasaki J, Hazeki K, Kasuu Y, Sasaki T, Hazeki O. Myeloid cell-specific inositol polyphosphate-4-phosphatase type I knockout mice impair bacteria clearance in a murine peritonitis model. Innate Immun 2016; 22:444-51. [DOI: 10.1177/1753425916652714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/10/2016] [Indexed: 11/17/2022] Open
Abstract
Phosphatidylinositol 3-kinase (PI3K)/Akt signaling has been implicated in the anti-inflammatory response in a mouse model of endotoxemia and sepsis. The present study focused on the role of inositol polyphosphate-4-phosphatase type I (Inpp4a), which dephosphorylates PtdIns(3,4)P2 to PtdIns(3)P, in bacterial infections. We prepared myeloid cell-specific Inpp4a-conditional knockout mice. Macrophages from these mice showed increased Akt phosphorylation and reduced production of inflammatory cytokines in response to LPS or Escherichia coli in vitro. The Inpp4a knockout mice survived for a shorter time than wild type mice after i.p. infection with E. coli, with less production of inflammatory cytokines. Additionally, E. coli clearance from blood and lung was significantly impaired in the knockout mice. A likely mechanism is that the Inpp4a-catalyzed dephosphorylation of PtdIns(3,4)P2 down-regulates Akt pathways, which, in turn, increases the production of inflammatory mediators. This mechanism at least fits the decreased E. coli clearance and short survival in the Inpp4a knockout mice.
Collapse
Affiliation(s)
- Shin Morioka
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Kiyomi Nigorikawa
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Junko Sasaki
- Department of Pathology and Immunology, Akita University School of Medicine, Akita 010-8543, Japan
| | - Kaoru Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yoshihiro Kasuu
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Takehiko Sasaki
- Department of Pathology and Immunology, Akita University School of Medicine, Akita 010-8543, Japan
| | - Osamu Hazeki
- Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| |
Collapse
|
44
|
Weehuizen TAF, Hommes TJ, Lankelma JM, de Jong HK, Roelofs JJ, de Vos AF, Colonna M, van der Poll T, Wiersinga WJ. Triggering Receptor Expressed on Myeloid Cells (TREM)-2 Impairs Host Defense in Experimental Melioidosis. PLoS Negl Trop Dis 2016; 10:e0004747. [PMID: 27253382 PMCID: PMC4890812 DOI: 10.1371/journal.pntd.0004747] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/07/2016] [Indexed: 12/22/2022] Open
Abstract
Background Triggering receptor expressed on myeloid cells (TREM) -1 and TREM-2 are key regulators of the inflammatory response that are involved in the clearance of invading pathogens. Melioidosis, caused by the "Tier 1" biothreat agent Burkholderia pseudomallei, is a common form of community-acquired sepsis in Southeast-Asia. TREM-1 has been suggested as a biomarker for sepsis and melioidosis. We aimed to characterize the expression and function of TREM-1 and TREM-2 in melioidosis. Methodology/Principal Findings Wild-type, TREM-1/3 (Trem-1/3-/-) and TREM-2 (Trem-2-/-) deficient mice were intranasally infected with live B. pseudomallei and killed after 24, and/or 72 h for the harvesting of lungs, liver, spleen, and blood. Additionally, survival studies were performed. Cellular functions were further analyzed by stimulation and/or infection of isolated cells. TREM-1 and TREM-2 expression was increased both in the lung and liver of B. pseudomallei-infected mice. Strikingly, Trem-2-/-, but not Trem-1/3-/-, mice displayed a markedly improved host defense as reflected by a strong survival advantage together with decreased bacterial loads, less inflammation and reduced organ injury. Cellular responsiveness of TREM-2, but not TREM-1, deficient blood and bone-marrow derived macrophages (BMDM) was diminished upon exposure to B. pseudomallei. Phagocytosis and intracellular killing of B. pseudomallei by BMDM and alveolar macrophages were TREM-1 and TREM-2-independent. Conclusions/Significance We found that TREM-2, and to a lesser extent TREM-1, plays a remarkable detrimental role in the host defense against a clinically relevant Gram-negative pathogen in mice: TREM-2 deficiency restricts the inflammatory response, thereby decreasing organ damage and mortality. Triggering receptor expressed on myeloid cells (TREM)-1 and -2 are receptors on immune cells that act as mediators of the innate immune response. It is thought that TREM-1 amplifies the immune response, while TREM-2 acts as a negative regulator. Previously, we found that TREM-1 is upregulated in melioidosis patients. In contrast, nothing is known on TREM-2 expression and its role in melioidosis. In this study we examined the expression and functional role of both TREM-1 and -2 in a murine melioidosis model. We found that TREM-1 and-2 expression was upregulated during melioidosis. Using our experimental melioidosis model, we observed that Trem-2-/- mice were protected against B.pseudomallei-induced lethality. Trem-2-/- mice demonstrated reduced bacterial loads, inflammation and organ damage compared to wild-type mice in experimental melioidosis. Despite reduced bacterial dissemination of B.pseudomallei to distant organs in Trem-1/3-/ mice-, no differences in survival were found between Trem-1/3-/- and wild-type mice during melioidosis. Lastly, we investigated cellular functions of TREM-1 and TREM-2 and found that TREM-2 deficiency led to decreased cellular responsiveness to B. pseudomallei infection. In conclusion, we found that TREM-2 plays an important role during experimental murine melioidosis. TREM-2-deficiency reduces inflammation and organ damage, thereby improving survival.
Collapse
Affiliation(s)
- Tassili A. F. Weehuizen
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
- * E-mail: ;
| | - Tijmen J. Hommes
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
| | - Jacqueline M. Lankelma
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
| | - Hanna K. de Jong
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
| | | | - Alex F. de Vos
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
| | - Marco Colonna
- Department of Pathology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Tom van der Poll
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
- Department of Medicine, Division of Infectious Diseases, Academic Medical Center, Amsterdam, the Netherlands
| | - W. Joost Wiersinga
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, the Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, the Netherlands
- Department of Medicine, Division of Infectious Diseases, Academic Medical Center, Amsterdam, the Netherlands
| |
Collapse
|
45
|
Kasamatsu J, Deng M, Azuma M, Funami K, Shime H, Oshiumi H, Matsumoto M, Kasahara M, Seya T. Double-stranded RNA analog and type I interferon regulate expression of Trem paired receptors in murine myeloid cells. BMC Immunol 2016; 17:9. [PMID: 27141827 PMCID: PMC4855714 DOI: 10.1186/s12865-016-0147-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 04/22/2016] [Indexed: 12/02/2022] Open
Abstract
Background Triggering receptors expressed on myeloid cells (Trem) proteins are a family of cell surface receptors used to control innate immune responses such as proinflammatory cytokine production in mice. Trem genes belong to a rapidly expanding family of receptors that include activating and inhibitory paired-isoforms. Results By comparative genomic analysis, we found that Trem4, Trem5 and Trem-like transcript-6 (Treml6) genes typically paired receptors. These paired Trem genes were murine-specific and originated from an immunoreceptor tyrosine-based inhibition motif (ITIM)-containing gene. Treml6 encoded ITIM, whereas Trem4 and Trem5 lacked the ITIM but possessed positively-charged residues to associate with DNAX activating protein of 12 kDa (DAP12). DAP12 was directly associated with Trem4 and Trem5, and DAP12 coupling was mandatory for their expression on the cell surface. In bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs), and splenic DC subsets, polyinosinic-polycytidylic acid (polyI:C) followed by type I interferon (IFN) production induced Trem4 and Treml6 whereas polyI:C or other TLR agonists failed to induce the expression of Trem5. PolyI:C induced Treml6 and Trem4 more efficiently in BMDMs than BMDCs. Treml6 was more potentially up-regulated in conventional DC (cDCs) and plasmacytoid DC (pDCs) than Trem4 in mice upon in vivo stimulation with polyI:C. Discussion Treml6-dependent inhibitory signal would be dominant in viral infection compared to resting state. Though no direct ligands of these Trem receptors have been determined, the results infer that a set of Trem receptors are up-regulated in response to viral RNA to regulate myeloid cell activation through modulation of DAP12-associated Trem4 and ITIM-containing Treml6. Electronic supplementary material The online version of this article (doi:10.1186/s12865-016-0147-y) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jun Kasamatsu
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Department of Pathology I, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Present address: Department of Microbiology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Mengyao Deng
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Masahiro Azuma
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Kenji Funami
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Hiroaki Shime
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Hiroyuki Oshiumi
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.,Present address: Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto, Japan
| | - Misako Matsumoto
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Masanori Kasahara
- Department of Pathology I, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
| | - Tsukasa Seya
- Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan. .,Department of Vaccine Immunology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8638, Japan.
| |
Collapse
|
46
|
Hommes TJ, Dessing MC, Veer CV', Florquin S, Colonna M, de Vos AF, van der Poll T. Role of triggering receptor expressed on myeloid cells-1/3 in Klebsiella-derived pneumosepsis. Am J Respir Cell Mol Biol 2016; 53:647-55. [PMID: 25860078 DOI: 10.1165/rcmb.2014-0485oc] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Triggering receptor expressed on myeloid cells (TREM)-1 and -2 can affect Toll-like receptor-mediated activation of immune cells. Klebsiella pneumoniae is a common cause of pneumonia-derived sepsis. Here we studied the role of TREM-1/3 and TREM-2 in the host response during Klebsiella pneumonia. Macrophages lacking either TREM-1/3 or TREM-2 were tested for their responsiveness toward K. pneumoniae and for their capacity to internalize this pathogen in vitro. TREM-1/3- and TREM-2-deficient mice were infected with K. pneumoniae via the airways, and their responses were compared with those in wild-type mice. TREM-1/3-deficient macrophages produced lower cytokine levels upon exposure to K. pneumoniae, whereas TREM-2-deficient macrophages released higher cytokine concentrations. TREM-2-deficient, but not TREM-1/3-deficient, macrophages showed a reduced capacity to phagocytose K. pneumoniae. TREM-1/3-deficient mice showed an impaired host defense during Klebsiella pneumonia, as reflected by worsened survival and increased bacterial growth and dissemination. In contrast, TREM-2 deficiency did not affect disease outcome. Although TREM-1/3 and TREM-2 influence macrophage responsiveness to K. pneumoniae in vitro, only TREM-1/3 contribute to the host response during Klebsiella pneumonia in vivo, serving a protective role.
Collapse
Affiliation(s)
- Tijmen J Hommes
- 1 Center for Experimental and Molecular Medicine.,2 Center for Infection and Immunity
| | | | - Cornelis van 't Veer
- 1 Center for Experimental and Molecular Medicine.,2 Center for Infection and Immunity
| | | | - Marco Colonna
- 4 Department of Pathology, Washington University in St. Louis, St. Louis, Missouri
| | - Alex F de Vos
- 1 Center for Experimental and Molecular Medicine.,2 Center for Infection and Immunity
| | - Tom van der Poll
- 1 Center for Experimental and Molecular Medicine.,2 Center for Infection and Immunity.,5 Division of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands; and
| |
Collapse
|
47
|
Painter MM, Atagi Y, Liu CC, Rademakers R, Xu H, Fryer JD, Bu G. TREM2 in CNS homeostasis and neurodegenerative disease. Mol Neurodegener 2015; 10:43. [PMID: 26337043 PMCID: PMC4560063 DOI: 10.1186/s13024-015-0040-9] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/19/2015] [Indexed: 02/07/2023] Open
Abstract
Myeloid-lineage cells accomplish a myriad of homeostatic tasks including the recognition of pathogens, regulation of the inflammatory milieu, and mediation of tissue repair and regeneration. The innate immune receptor and its adaptor protein—triggering receptor expressed on myeloid cells 2 (TREM2) and DNAX-activating protein of 12 kDa (DAP12)—possess the ability to modulate critical cellular functions via crosstalk with diverse signaling pathways. As such, mutations in TREM2 and DAP12 have been found to be associated with a range of disease phenotypes. In particular, mutations in TREM2 increase the risk for Alzheimer's disease and other neurodegenerative disorders. The leading hypothesis is that microglia, the resident immune cells of the central nervous system, are the major myeloid cells affected by dysregulated TREM2-DAP12 function. Here, we review how impaired signaling by the TREM2-DAP12 pathway leads to altered immune responses in phagocytosis, cytokine production, and microglial proliferation and survival, thus contributing to disease pathogenesis.
Collapse
Affiliation(s)
- Meghan M Painter
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China.
| | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China.
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA. .,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, 361102, China. .,Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
| |
Collapse
|
48
|
TREM-2 Receptor Expression Increases with 25(OH)D Vitamin Serum Levels in Patients with Pulmonary Sarcoidosis. Mediators Inflamm 2015; 2015:181986. [PMID: 26166951 PMCID: PMC4488005 DOI: 10.1155/2015/181986] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 05/08/2015] [Accepted: 05/18/2015] [Indexed: 11/17/2022] Open
Abstract
TREM-1 and TREM-2 molecules are members of the TREM transmembrane glycoproteins. In our previous study we identified increased expressions of TREM-1 and TREM-2 receptors in pulmonary sarcoidosis (PS). Only a few studies concerning the association between vitamin D and TREM receptor expression can be found. The aim of our current study was to determine the association between the levels of an inactive form of 25(OH)D vitamin and TREM-1 and TREM-2 receptor expressions. We have detected low levels of 25(OH)D vitamin in 79% of PS patients. Only 21% of patients had normal serum level of 25(OH)D vitamin with values clustered within the low-normal range. The most striking findings were the increased TREM-2 expressions on myeloid cells surfaces in BALF of PS patients with normal 25(OH)D vitamin serum levels compared with those with its decreased levels. The total number of TREM-2 positive cells was 5.7 times higher and the percentage of TREM-2 positive cells was also significantly increased in BALF of PS patients with normal compared to PS patients with low 25(OH)D vitamin serum levels. A significant correlation between total TREM-2 expression and vitamin D levels has been detected too. However, we have not detected similar differences in TREM-1expression and 25(OH)D vitamin serum levels.
Collapse
|