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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.
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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.
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2
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Hwang M, Bergmann CC. Neurotropic murine coronavirus mediated demyelination: Factors dampening pathogenesis. J Neuroimmunol 2024; 393:578382. [PMID: 38850674 DOI: 10.1016/j.jneuroim.2024.578382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/12/2024] [Accepted: 05/31/2024] [Indexed: 06/10/2024]
Abstract
Virus infections and autoimmune responses are implicated as primary triggers of demyelinating diseases. Specifically, the association of Epstein-Barr virus (EBV) infection with development of multiple sclerosis (MS) has re-ignited an interest in virus induced autoimmune responses to CNS antigens. Nevertheless, demyelination may also be caused by immune mediated bystander pathology in an attempt to control direct infection in the CNS. Tissue damage as a result of anti-viral responses or low level viral persistence may lead to immune activation manifesting in demyelinating lesions, axonal damage and clinical symptoms. This review focuses on the neurotropic mouse coronavirus induced demyelination model to highlight how immune responses activated during the acute phase pave the way to dampen pathology and promote repair. We specifically discuss the role of immune dampening factors programmed cell death ligand 1 (PD-L1) and interleukin (IL)-10, as well as microglia and triggering receptor expressed on myeloid cells 2 (Trem2), in limiting demyelination independent of viral persistence.
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Affiliation(s)
- Mihyun Hwang
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA; Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Cornelia C Bergmann
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA; Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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3
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Lee RJ, Adappa ND, Palmer JN. Effects of Akt Activator SC79 on Human M0 Macrophage Phagocytosis and Cytokine Production. Cells 2024; 13:902. [PMID: 38891035 PMCID: PMC11171788 DOI: 10.3390/cells13110902] [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: 04/25/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 06/20/2024] Open
Abstract
Akt is an important kinase in metabolism. Akt also phosphorylates and activates endothelial and neuronal nitric oxide (NO) synthases (eNOS and nNOS, respectively) expressed in M0 (unpolarized) macrophages. We showed that e/nNOS NO production downstream of bitter taste receptors enhances macrophage phagocytosis. In airway epithelial cells, we also showed that the activation of Akt by a small molecule (SC79) enhances NO production and increases levels of nuclear Nrf2, which reduces IL-8 transcription during concomitant stimulation with Toll-like receptor (TLR) 5 agonist flagellin. We hypothesized that SC79's production of NO in macrophages might likewise enhance phagocytosis and reduce the transcription of some pro-inflammatory cytokines. Using live cell imaging of fluorescent biosensors and indicator dyes, we found that SC79 induces Akt activation, NO production, and downstream cGMP production in primary human M0 macrophages. This was accompanied by a reduction in IL-6, IL-8, and IL-12 production during concomitant stimulation with bacterial lipopolysaccharide, an agonist of pattern recognition receptors including TLR4. Pharmacological inhibitors suggested that this effect was dependent on Akt and Nrf2. Together, these data suggest that several macrophage immune pathways are regulated by SC79 via Akt. A small-molecule Akt activator may be useful in some infection settings, warranting future in vivo studies.
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Affiliation(s)
- Robert J. Lee
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (N.D.A.); (J.N.P.)
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nithin D. Adappa
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (N.D.A.); (J.N.P.)
| | - James N. Palmer
- Department of Otorhinolaryngology—Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (N.D.A.); (J.N.P.)
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Huang P, Zhang Z, Zhang P, Feng J, Xie J, Zheng Y, Liang X, Zhu B, Chen Z, Feng S, Wang L, Lu J, Liu Y, Zhang Y. TREM2 Deficiency Aggravates NLRP3 Inflammasome Activation and Pyroptosis in MPTP-Induced Parkinson's Disease Mice and LPS-Induced BV2 Cells. Mol Neurobiol 2024; 61:2590-2605. [PMID: 37917301 PMCID: PMC11043123 DOI: 10.1007/s12035-023-03713-0] [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: 02/03/2023] [Accepted: 09/22/2023] [Indexed: 11/04/2023]
Abstract
Microglia-mediated neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD). Triggering receptor expressed on myeloid cells 2 (TREM2) confers strong neuroprotective effects in PD by regulating the phenotype of microglia. Recent studies suggest that TREM2 regulates high glucose-induced microglial inflammation through the NLRP3 signaling pathway. This study aimed to investigate the effect of TREM2 on NLRP3 inflammasome activation and neuroinflammation in PD. Mice were injected with AAV-TREM2-shRNA into both sides of the substantia nigra using a stereotactic injection method, followed by intraperitoneal injection of MPTP to establish chronic PD mouse model. Behavioral assessments including the pole test and rotarod test were conducted to evaluate the effects of TREM2 deficiency on MPTP-induced motor dysfunction. Immunohistochemistry of TREM2 and tyrosine hydroxylase (TH), immunohistochemistry and immunofluorescence Iba1, Western blot of NLRP3 inflammasome and its downstream inflammatory factors IL-1β and IL-18, and the key pyroptosis factors GSDMD and GSDMD-N were performed to explore the effect of TREM2 on NLRP3 inflammasome and neuroinflammation. In an in vitro experiment, lentivirus was used to interfere with the expression of TREM2 in BV2 microglia, and then lipopolysaccharide (LPS) and adenopterin nucleoside triphosphate (ATP) were used to stimulate inflammation to construct a cellular inflammation model. The expression differences of NLRP3 inflammasome and its components were detected by qPCR and Western blot. In vivo, TREM2 knockdown aggravated the loss of dopaminergic neuron and the decline of motor function. After TREM2 knockdown, the number of activated microglia was significantly increased, and the expression of cleaved caspase-1, NLRP3 inflammasome, IL-1β, GSDMD, and GSDMD-N was increased. In vitro, TREM2 knockdown aggravated the inflammatory response of BV2 cells stimulated by LPS and promoted the activation of NLRP3 inflammasome through the NF-κB pathway. In addition, TREM2 knockdown also promoted the expression of TLR4/MyD88, an upstream factor of the NF-κB pathway. Our vivo and vitro data showed that TREM2 knockdown promoted NLRP3 inflammasome activation and downstream inflammatory response, promoted pyroptosis, and aggravated dopaminergic neuron loss. TREM2 acts as an anti-inflammatory in PD through the TLR4/MyD88/NF-κB pathway, which extends previous findings and supports the notion that TREM2 ameliorates neuroinflammation in PD.
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Affiliation(s)
- Peiting Huang
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Zhanyu Zhang
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Piao Zhang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Jiezhu Feng
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Jianwei Xie
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Yinjuan Zheng
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Xiaomei Liang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Baoyu Zhu
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Zhenzhen Chen
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Shujun Feng
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Lijuan Wang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China
| | - Jiahong Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
| | - Yawei Liu
- Department of Neurosurgery & Medical Research Center, Shunde Hospital, Southern Medical University (The First People's Hospital of Shunde Foshan), Foshan, Guangdong, China.
| | - Yuhu Zhang
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong Province, China.
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong Province, China.
- Guangzhou Key Laboratory of Diagnosis and Treatment for Neurodegenerative Diseases, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Guangzhou, 510080, China.
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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.
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Affiliation(s)
| | | | | | - Marcelle Silva-Sales
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Brazil
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6
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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.
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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
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Qian H, Gao F, Wu X, Lin D, Huang Y, Chen A, Deng J, Gong C, Chen X, Zheng X. Activation of the CD200/CD200R1 axis attenuates neuroinflammation and improves postoperative cognitive dysfunction via the PI3K/Akt/NF-κB signaling pathway in aged mice. Inflamm Res 2023; 72:2127-2144. [PMID: 37902837 DOI: 10.1007/s00011-023-01804-1] [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: 05/18/2023] [Revised: 08/28/2023] [Accepted: 10/02/2023] [Indexed: 11/01/2023] Open
Abstract
BACKGROUND Postoperative cognitive dysfunction (POCD) is a neurological complication occurring after anesthesia and surgery. Neuroinflammation plays a critical role in the pathogenesis of POCD, and the activation of the cluster of differentiation 200 (CD200)/CD200R1 axis improves neurological recovery in various neurological disorders by modulating inflammation. The aim of this study was to investigate the impact and underlying mechanism of CD200/CD200R1 axis on POCD in aged mice. METHODS The model of POCD was established in aged mice. To assess the learning and memory abilities of model mice, the Morris water maze test was implemented. CD200Fc (CD200 fusion protein), CD200R1 Ab (anti-CD200R1 antibody), and 740Y-P (a specific PI3K activator) were used to evaluate the effects of the CD200/CD200R1/PI3K/Akt/NF-κB signaling pathway on hippocampal microglial polarization, neuroinflammation, synaptic activity, and cognition in mice. RESULTS It was observed that anesthesia/surgery induced cognitive decline in aged mice, increased the levels of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1 β and decreased the levels of postsynaptic density protein 95 (PSD-95), synaptophysin (SYN) in the hippocampus. Moreover, CD200Fc and 740Y-P attenuated neuroinflammation and synaptic deficits and reversed cognitive impairment via the phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt)/nuclear factor-kappa B (NF-κB) signaling pathway, whereas CD200R1 Ab administration exerted the opposite effects. Our results further show that the CD200/CD200R1 axis modulates M1/M2 polarization in hippocampal microglia via the PI3K/Akt/NF-κB signaling pathway. CONCLUSIONS Our findings indicate that the activation of the CD200/CD200R1 axis reduces neuroinflammation, synaptic deficits, and cognitive impairment in the hippocampus of aged mice by regulating microglial M1/M2 polarization via the PI3K/Akt/NF-κB signaling pathway.
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Affiliation(s)
- Haitao Qian
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Fei Gao
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Xuyang Wu
- College of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Daoyi Lin
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Yongxin Huang
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Andi Chen
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Jianhui Deng
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Cansheng Gong
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China
| | - Xiaohui Chen
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China.
| | - Xiaochun Zheng
- Shengli Clinical Medical College of Fujian Medical University, Department of Anesthesiology, Fujian Provincial Hospital, Fuzhou, China.
- Fujian Emergency Medical Center, Fujian Provincial Key Laboratory of Critical Care Medicine, Fujian Provincial Co-Constructed Laboratory of "Belt and Road", Fuzhou, China.
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Pang XW, Chu YH, Zhou LQ, Chen M, You YF, Tang Y, Yang S, Zhang H, Xiao J, Deng G, Wang W, Shang K, Qin C, Tian DS. Trem2 deficiency attenuates microglial phagocytosis and autophagic-lysosomal activation in white matter hypoperfusion. J Neurochem 2023; 167:489-504. [PMID: 37823326 DOI: 10.1111/jnc.15987] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/23/2023] [Accepted: 09/23/2023] [Indexed: 10/13/2023]
Abstract
Chronic cerebral hypoperfusion leads to sustained demyelination and a unique response of microglia. Triggering receptor expressed on myeloid cells 2 (Trem2), which is expressed exclusively on microglia in the central nervous system (CNS), plays an essential role in microglial response in various CNS disorders. However, the specific role of Trem2 in chronic cerebral hypoperfusion has not been elucidated. In this study, we investigated the specific role of Trem2 in a mouse model of chronic cerebral hypoperfusion induced by bilateral carotid artery stenosis (BCAS). Our results showed that chronic hypoperfusion induced white matter demyelination, microglial phagocytosis, and activation of the microglial autophagic-lysosomal pathway, accompanied by an increase in Trem2 expression. After Trem2 knockout, we observed attenuation of white matter lesions and microglial response. Trem2 deficiency also suppressed microglial phagocytosis and relieved activation of the autophagic-lysosomal pathway, leading to microglial polarization towards anti-inflammatory and homeostatic phenotypes. Furthermore, Trem2 knockout inhibited lipid droplet accumulation in microglia in vitro. Collectively, these findings suggest that Trem2 deficiency ameliorated microglial phagocytosis and autophagic-lysosomal activation in hypoperfusion-induced white matter injury, and could be a promising target for the treatment of chronic cerebral hypoperfusion.
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Affiliation(s)
- Xiao-Wei Pang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Yun-Hui Chu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Luo-Qi Zhou
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Man Chen
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Yun-Fan You
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Yue Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Sheng Yang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Hang Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Xiao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Ke Shang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Chuan Qin
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan, China
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9
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Rosa CP, Belo TCA, Santos NCDM, Silva EN, Gasparotto J, Corsetti PP, de Almeida LA. Reactive oxygen species trigger inflammasome activation after intracellular microbial interaction. Life Sci 2023; 331:122076. [PMID: 37683723 DOI: 10.1016/j.lfs.2023.122076] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/16/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
The intracellular production of reactive oxygen species (ROS), composed of oxygen-reduced molecules, is important not only because of their lethal effects on microorganisms but also due to their potential inflammatory and metabolic regulation properties. The ROS pro-inflammatory properties are associated with the second signal to inflammasome activation, leading to cleaving pro-IL-1β and pro-IL18 before their secretion, as well as gasdermin-D, leading to pyroptosis. Some microorganisms can modulate NLRP3 and AIM-2 inflammasomes through ROS production: whilst Mycobacterium bovis, Mycobacterium kansasii, Francisella novicida, Brucella abortus, Listeria monocytogenes, Influenza virus, Syncytial respiratory virus, Porcine reproductive and respiratory syndrome virus, SARS-CoV, Mayaro virus, Leishmania amazonensis and Plasmodium sp. enhance inflammasome assembly, Hepatitis B virus, Mycobacterium marinum, Mycobacterium tuberculosis, Francisella tularensis and Leishmania sp. disrupt it. This process represents a recent cornerstone in our knowledge of the immunology of intracellular pathogens, which is reviewed in this mini-review.
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Affiliation(s)
- Caio Pupin Rosa
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Thiago Caetano Andrade Belo
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Natália Cristina de Melo Santos
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Evandro Neves Silva
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Juciano Gasparotto
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Patrícia Paiva Corsetti
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil
| | - Leonardo Augusto de Almeida
- Laboratory of Molecular Biology of Microorganisms, Federal University of Alfenas (UNIFAL), Alfenas 37130-001, Minas Gerais, Brazil.
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10
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Peilin W, Ying P, Renyuan W, Zhuoxuan L, Zhenwu Y, Mai Z, Jianguo S, Hao Z, Gang Y, Lin L, Haodong L. Size-dependent gold nanoparticles induce macrophage M2 polarization and promote intracellular clearance of Staphylococcus aureus to alleviate tissue infection. Mater Today Bio 2023; 21:100700. [PMID: 37455821 PMCID: PMC10338365 DOI: 10.1016/j.mtbio.2023.100700] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/19/2023] [Accepted: 05/29/2023] [Indexed: 07/18/2023] Open
Abstract
Tissue infection typically results from blood transmission or the direct inoculation of bacteria following trauma. The pathogen-induced destruction of tissue prevents antibiotics from penetrating the infected site, and severe inflammation further impairs the efficacy of conventional treatment. The current study describes the size-dependent induction of macrophage polarization using gold nanoparticles. Gold nanoparticles with a diameter of 50 nm (Au50) can induce M2 polarization in macrophages by inhibiting the NF-κB signaling pathway and stimulate an inflammatory response in the environment by inhibiting the MAPK signaling pathway LPS. Furthermore, the induced polarization and anti-inflammatory effects of the Au50 nanoparticles promoted the osteogenic differentiation of BMSCs in vitro. In addition, the overexpression of TREM2 in macrophage induced by Au50 nanoparticles was found to promote macrophage phagocytosis of Staphylococcus aureus, enhance the fusion of autophagosomes and lysosomes, accelerate the intracellular degradation of S. aureus, in addition to achieving an effective local treatment of osteomyelitis and infectious skin defects in conjunction with inflammatory regulation and accelerating bone regeneration. The findings, therefore, demonstrate that Au50 nanoparticles can be utilized as a promising nanomaterial for in vivo treatment of infections.
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Affiliation(s)
- Wang Peilin
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Peng Ying
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Wang Renyuan
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Li Zhuoxuan
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Yang Zhenwu
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Zhao Mai
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Song Jianguo
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Zhang Hao
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Yin Gang
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Lin Lin
- School of Chemical and Environmental, Engineering, Shanghai Institute of Technology, Shanghai 201418, China
| | - Lin Haodong
- Trauma Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
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11
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Carabalí-Isajar ML, Rodríguez-Bejarano OH, Amado T, Patarroyo MA, Izquierdo MA, Lutz JR, Ocampo M. Clinical manifestations and immune response to tuberculosis. World J Microbiol Biotechnol 2023; 39:206. [PMID: 37221438 DOI: 10.1007/s11274-023-03636-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/29/2023] [Indexed: 05/25/2023]
Abstract
Tuberculosis is a far-reaching, high-impact disease. It is among the top ten causes of death worldwide caused by a single infectious agent; 1.6 million tuberculosis-related deaths were reported in 2021 and it has been estimated that a third of the world's population are carriers of the tuberculosis bacillus but do not develop active disease. Several authors have attributed this to hosts' differential immune response in which cellular and humoral components are involved, along with cytokines and chemokines. Ascertaining the relationship between TB development's clinical manifestations and an immune response should increase understanding of tuberculosis pathophysiological and immunological mechanisms and correlating such material with protection against Mycobacterium tuberculosis. Tuberculosis continues to be a major public health problem globally. Mortality rates have not decreased significantly; rather, they are increasing. This review has thus been aimed at deepening knowledge regarding tuberculosis by examining published material related to an immune response against Mycobacterium tuberculosis, mycobacterial evasion mechanisms regarding such response and the relationship between pulmonary and extrapulmonary clinical manifestations induced by this bacterium which are related to inflammation associated with tuberculosis dissemination through different routes.
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Grants
- a Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia
- a Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia
- a Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia
- a Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, Bogotá 111321, Colombia
- b PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Carrera 24#63C-69, Bogotá 111221, Colombia
- c Health Sciences Faculty, Universidad de Ciencias Aplicadas y Ambientales (UDCA), Calle 222#55-37, Bogotá 111166, Colombia
- d Faculty of Medicine, Universidad Nacional de Colombia, Carrera 45#26-85, Bogotá 111321, Colombia
- e Medicine Department, Hospital Universitario Mayor Mederi, Calle 24 # 29-45, Bogotá 111411. Colombia
- e Medicine Department, Hospital Universitario Mayor Mederi, Calle 24 # 29-45, Bogotá 111411. Colombia
- f Universidad Distrital Francisco José de Caldas, Carrera 3#26A-40, Bogotá 110311, Colombia
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Affiliation(s)
- Mary Lilián Carabalí-Isajar
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, 111321, Bogotá, Colombia
- Biomedical and Biological Sciences Programme, Universidad del Rosario, Carrera 24#63C-69, 111221, Bogotá, Colombia
| | | | - Tatiana Amado
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, 111321, Bogotá, Colombia
| | - Manuel Alfonso Patarroyo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, 111321, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Carrera 45#26-85, 111321, Bogotá, Colombia
| | - María Alejandra Izquierdo
- Medicine Department, Hospital Universitario Mayor Mederi, Calle 24 # 29-45, 111411, Bogotá, Colombia
| | - Juan Ricardo Lutz
- Medicine Department, Hospital Universitario Mayor Mederi, Calle 24 # 29-45, 111411, Bogotá, Colombia.
| | - Marisol Ocampo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50#26-20, 111321, Bogotá, Colombia.
- Universidad Distrital Francisco José de Caldas, Carrera 3#26A-40, 110311, Bogotá, Colombia.
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12
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Fu A, Qiao F, Feng H, Luo Q. Inhibition of TREM-1 Ameliorates Lipopolysaccharide-induced Depressive-like Behaviors by Alleviating Neuroinflammation in the PFC via PI3K/Akt Signaling Pathway. Behav Brain Res 2023; 449:114464. [PMID: 37142164 DOI: 10.1016/j.bbr.2023.114464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/19/2023] [Accepted: 05/01/2023] [Indexed: 05/06/2023]
Abstract
Neuroinflammation is closely related to depression and is a key pathophysiological process of depression. Triggering receptor expressed on myeloid cells 1 (TREM-1) has been proven to exert proinflammatory effects in various diseases. However, the role of TREM-1 in depression has not been elucidated. Thus, we hypothesized that TREM-1 inhibition might have protective effects in depression. Here, lipopolysaccharide (LPS) was used to induce depressive-like behaviors in mice, LP17 was treated to inhibit TREM-1, and LY294002 was administrated to inhibit phosphatidylinositol 3-kinase (PI3K) which is one of the downstream of TREM-1. Physical and neurobehavioral tests, Western blot analysis, and immunofluorescence staining were performed in this study. We found that LPS caused significant depressive-like behaviors in mice, including body weight decline, anodynia (sucrose preference decrease), lack of locomotor activity, and desperation in tail suspension test (TST) and forced swimming test (FST). Next, we revealed that TREM-1 was expressed on microglia, neurons, and astrocytes in the prefrontal cortex (PFC) after LPS administration. TREM-1 inhibition by LP17 suppressed the expression of TREM-1 in the PFC. In addition, LP17 could alleviate neuroinflammation and microglial activation in the PFC. Meanwhile, LP17 could prevent damage of LPS to neuronal primary cilia and neuronal activity. Finally, we revealed that PI3K/Akt might exert crucial role in the protective effects of TREM-1 inhibition to depressive-like behaviors induced by LPS. Taken together, TREM-1 inhibition by LP17 could alleviate depressive-like behaviors induced by LPS by mitigating neuroinflammation in the PFC via PI3K/Akt signaling pathway. Finally, we demonstrated that TREM-1 might be a promising therapeutic target for treatment of depression.
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Affiliation(s)
- Anhui Fu
- Department of Neurosurgery, Nanchong Central Hospital, The Second Clinical Medical College of North Sichuan Medical College, Nanchong, China
| | - Fei Qiao
- Department of Neurosurgery, Nanchong Central Hospital, The Second Clinical Medical College of North Sichuan Medical College, Nanchong, China
| | - Hao Feng
- Department of Neurosurgery, Nanchong Central Hospital, The Second Clinical Medical College of North Sichuan Medical College, Nanchong, China
| | - Qing Luo
- Department of Ultrasound, Chonggang general hospital, Chongqing, China.
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13
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Hwang M, Savarin C, Kim J, Powers J, Towne N, Oh H, Bergmann CC. Trem2 deficiency impairs recovery and phagocytosis and dysregulates myeloid gene expression during virus-induced demyelination. J Neuroinflammation 2022; 19:267. [PMID: 36333761 PMCID: PMC9635103 DOI: 10.1186/s12974-022-02629-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
Background Triggering receptor expressed on myeloid cells 2 (Trem2) plays a protective role in neurodegenerative diseases. By contrast, Trem2 functions can exacerbate tissue damage during respiratory viral or liver infections. We, therefore, investigated the role of Trem2 in a viral encephalomyelitis model associated with prominent Th1 mediated antiviral immunity leading to demyelination. Methods Wild-type (WT) and Trem2 deficient (Trem2−/−) mice were infected with a sublethal glia tropic murine coronavirus (MHV–JHM) intracranially. Disease progression and survival were monitored daily. Leukocyte accumulation and pathological features including demyelination and axonal damage in spinal cords (SC) were determined by flow cytometry and tissue section immunofluorescence analysis. Expression of select inflammatory cytokines and chemokines was measured by RT-PCR and global myeloid cell gene expression in SC-derived microglia and infiltrated bone-marrow-derived macrophages (BMDM) were determined using the Nanostring nCounter platform. Results BMDM recruited to SCs in response to infection highly upregulated Trem2 mRNA compared to microglia coincident with viral control. Trem2 deficiency did not alter disease onset or severity, but impaired clinical recovery after onset of demyelination. Disease progression in Trem2−/− mice could not be attributed to altered virus control or an elevated proinflammatory response. A prominent difference was increased degenerated myelin not associated with the myeloid cell markers IBA1 and/or CD68. Gene expression profiles of SC-derived microglia and BMDM further revealed that Trem2 deficiency resulted in impaired upregulation of phagocytosis associated genes Lpl and Cd36 in microglia, but a more complex pattern in BMDM. Conclusions Trem2 deficiency during viral-induced demyelination dysregulates expression of other select genes regulating phagocytic pathways and lipid metabolism, with distinct effects on microglia and BMDM. The ultimate failure to remove damaged myelin is reminiscent of toxin or autoimmune cell-induced demyelination models and supports that Trem2 function is regulated by sensing tissue damage including a dysregulated lipid environment in very distinct inflammatory environments. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02629-1.
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14
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Han X, Cheng X, Xu J, Liu Y, Zhou J, Jiang L, Gu X, Xia T. Activation of TREM2 attenuates neuroinflammation via PI3K/Akt signaling pathway to improve postoperative cognitive dysfunction in mice. Neuropharmacology 2022; 219:109231. [PMID: 36041498 DOI: 10.1016/j.neuropharm.2022.109231] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/14/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022]
Abstract
Postoperative cognitive dysfunction (POCD) is a common postoperative complication involving the central nervous system, but the underlying mechanism is not well understood. Neuroinflammation secondary to surgery and anesthesia is strongly correlated with POCD. A key aspect of neuroinflammation is microglia activation. Triggering receptor expressed on myeloid cells (TREM)2, which is highly expressed in microglia, is an innate immune receptor that modulates microglia function. In this study we investigated the role of TREM2 in cognitive impairment and microglia-mediated neuroinflammation using a mouse model of POCD and in vitro systems. We found that hippocampus-dependent learning and memory were impaired in POCD mice, which was accompanied by activation of microglia and downregulation of TREM2. Pretreatment with the TREM2 agonist heat shock protein (HSP)60 inhibited surgery-induced microglia activation and alleviated postoperative cognitive impairment. In BV2 microglial cells, the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 significantly reversed the attenuation of TREM2 activation on lipopolysaccharide (LPS)-induced neuroinflammation and abrogated the protective effect of activated TREM2 against LPS-induced neuronal injury in a microglia/neuron coculture system. Accordingly, the beneficial effects of TREM2 activation on cognitive function were reversed by preoperative administration of LY294002 in the POCD mouse model. These results demonstrate that TREM2 is involved in the regulation of the inflammatory response mediated by microglia and cognitive impairment following surgery. Activation of TREM2 can attenuate neuroinflammation by modulating PI3K/protein kinase B (Akt) signaling, thereby alleviating postoperative learning and memory deficits.
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Affiliation(s)
- Xue Han
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Xiaolei Cheng
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China
| | - Jiyan Xu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Yujia Liu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Jiawen Zhou
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Linhao Jiang
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Xiaoping Gu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China.
| | - Tianjiao Xia
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China; State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China.
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15
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Abstract
Macrophage surface receptors are critical for pathogen defense, as they are the gatekeepers for pathogen entry and sensing, which trigger robust immune responses. TREM2 (triggering receptor expressed on myeloid cells 2) is a transmembrane surface receptor that mediates anti-inflammatory immune signaling. A recent study showed that TREM2 is a receptor for mycolic acids in the mycobacterial cell wall and inhibits macrophage activation. However, the underlying functional mechanism of how TREM2 regulates the macrophage antimycobacterial response remains unclear. Here, we show that Mycobacterium tuberculosis, the causative agent for tuberculosis, specifically binds to human TREM2 to disable the macrophage antibacterial response. Live but not killed mycobacteria specifically trigger the upregulation of TREM2 during macrophage infection through a mechanism dependent on STING (the stimulator of interferon genes). TREM2 facilitated uptake of M. tuberculosis into macrophages and is responsible for blocking the production of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and reactive oxygen species (ROS), while enhancing the production of interferon-β (IFN-β) and IL-10. TREM2-mediated blockade of ROS production promoted the survival of M. tuberculosis within infected macrophages. Consistent with this, genetic deletion or antibody-mediated neutralization of TREM2 reduced the intracellular survival of M. tuberculosis through enhanced production of ROS. Importantly, inhibition of type I IFN signaling in TREM2-overexpressing macrophages restored the ability of these cells to produce inflammatory cytokines and ROS, resulting in normal levels of intracellular bacteria killing. Collectively, our study identifies TREM2 as an attractive host receptor for host-directed antimycobacterial therapeutics. IMPORTANCE Mycobacterium tuberculosis is one of the most ancient bacterial pathogens and remains the leading cause of death from a single bacterial agent. The success of M. tuberculosis relies greatly on its ability to parasitize and disable its host macrophages. Previous studies have found that M. tuberculosis uses its unique cell wall lipids to manipulate the immune response by binding to specific surface receptors on macrophages. Our study reveals that M. tuberculosis binds to TREM2, an immunomodulatory receptor expressed on macrophages, to facilitate a "silent" mode of entry. Increased levels of TREM2 triggered by intracellular sensing of M. tuberculosis promoted the intracellular survival of M. tuberculosis through type I IFN-driven inhibition of reactive oxygen species (ROS) and proinflammatory cytokine production. Importantly, deletion of TREM2 reversed the effects of "silent" entry and resulted in increased production of inflammatory cytokines, generation of ROS, and cell death. As such, antibody-mediated or pharmacological targeting of TREM2 could be a promising strategy for novel treatments against M. tuberculosis infection.
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Alby-Laurent F, Belaïdouni N, Blanchet B, Rousseau C, Llitjos JF, Sanquer S, Mira JP, Pène F, Toubiana J, Chiche JD. Low-dose mycophenolate mofetil improves survival in a murine model of Staphylococcus aureus sepsis by increasing bacterial clearance and phagocyte function. Front Immunol 2022; 13:939213. [PMID: 35936013 PMCID: PMC9351454 DOI: 10.3389/fimmu.2022.939213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Regulators of TLRs signaling pathways play an important role in the control of the pro-inflammatory response that contributes to sepsis-induced tissue injury. Mycophenolate mofetil, an immunosuppressive drug inhibiting lymphocyte proliferation, has been reported to be a regulator of TLRs signaling pathways. Whether MMF used at infra-immunosuppressive doses has an impact on survival and on innate immune response in sepsis is unknown.C57BL/6J mice were infected intraperitoneally with 108 CFU Staphylococcus aureus, and treated or not with low-dose of MMF (20mg/kg/day during 4 days). Survival rate and bacterial clearance were compared. Cytokine levels, quantitative and qualitative cellular responses were assessed. S. aureus – infected mice treated with MMF exhibited improved survival compared to non-treated ones (48% vs 10%, p<0.001). With the dose used for all experiments, MMF did not show any effect on lymphocyte proliferation. MMF treatment also improved local and systemic bacterial clearance, improved phagocytosis activity of peritoneal macrophages resulting in decreased inflammatory cytokines secretion. MMF-treated mice showed enhanced activation of NF-κB seemed with a suspected TLR4-dependent mechanism. These results suggest that infra-immunosuppressive doses of MMF improve host defense during S. aureus sepsis and protects infected mice from fatal outcome by regulating innate immune responses. The signaling pathways involved could be TLR4-dependent. This work brings new perspectives in pathogenesis and therapeutic approaches of severe infections.
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Affiliation(s)
- Fanny Alby-Laurent
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
| | - Nadia Belaïdouni
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
| | - Benoit Blanchet
- Department of Pharmocology and Toxicology, Cochin Hospital, Assistance Publique des hôpitaux de Paris (APHP), Université de Paris, Paris, France
| | - Christophe Rousseau
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
| | - Jean-François Llitjos
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
- Medical Intensive Care Unit, Cochin Hospital, APHP, Université de Paris, Paris, France
| | - Sylvia Sanquer
- Metabolic and Proteomic Biochemistry Department, Necker-Enfants malades Hospital, Université de Paris, Paris, France
| | - Jean-Paul Mira
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
- Medical Intensive Care Unit, Cochin Hospital, APHP, Université de Paris, Paris, France
| | - Frédéric Pène
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
- Medical Intensive Care Unit, Cochin Hospital, APHP, Université de Paris, Paris, France
| | - Julie Toubiana
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
- Department of General Pediatrics and Infectious Diseases, Necker-Enfants malades Hospital, APHP, Université de Paris, Paris, France
| | - Jean-Daniel Chiche
- Cochin Institute, Department of Infection, Immunity and Inflammation, Inserm U1016, Paris Descartes Sorbonne Paris Cité University UMR-S1016, Centre National de la Recherche Scientifique (CNRS) UMR 8104, Paris, France
- Medical Intensive Care Unit, Cochin Hospital, APHP, Université de Paris, Paris, France
- Department of Intensive Care Medicine, Hospital and University of Lausanne, Lausanne, Switzerland
- *Correspondence: Jean-Daniel Chiche,
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17
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Li RY, Qin Q, Yang HC, Wang YY, Mi YX, Yin YS, Wang M, Yu CJ, Tang Y. TREM2 in the pathogenesis of AD: a lipid metabolism regulator and potential metabolic therapeutic target. Mol Neurodegener 2022; 17:40. [PMID: 35658903 PMCID: PMC9166437 DOI: 10.1186/s13024-022-00542-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane immune receptor that is mainly expressed on microglia in the brain and macrophages in the periphery. Recent studies have identified TREM2 as a risk factor for Alzheimer’s disease (AD). Increasing evidence has shown that TREM2 can affect lipid metabolism both in the central nervous system (CNS) and in the periphery. In the CNS, TREM2 affects the metabolism of cholesterol, myelin, and phospholipids and promotes the transition of microglia into a disease-associated phenotype. In the periphery, TREM2 influences lipid metabolism by regulating the onset and progression of obesity and its complications, such as hypercholesterolemia, atherosclerosis, and nonalcoholic fatty liver disease. All these altered lipid metabolism processes could influence the pathogenesis of AD through several means, including affecting inflammation, insulin resistance, and AD pathologies. Herein, we will discuss a potential pathway that TREM2 mediates lipid metabolism to influence the pathogenesis of AD in both the CNS and periphery. Moreover, we discuss the possibility that TREM2 may be a key factor that links central and peripheral lipid metabolism under disease conditions, including AD. This link may be due to impacts on the integrity of the blood–brain barrier, and we introduce potential pathways by which TREM2 affects the blood–brain barrier. Moreover, we discuss the role of lipids in TREM2-associated treatments for AD. We propose some potential therapies targeting TREM2 and discuss the prospect and limitations of these therapies.
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Affiliation(s)
- Rui-Yang Li
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Qi Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Han-Chen Yang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Ying-Ying Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ying-Xin Mi
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Yun-Si Yin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Meng Wang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Chao-Ji Yu
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China
| | - Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, National Center for Neurological Disorders, Beijing, China.
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18
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Lu L, Liu X, Fu J, Liang J, Hou Y, Dou H. sTREM-1 promotes the phagocytic function of microglia to induce hippocampus damage via the PI3K-AKT signaling pathway. Sci Rep 2022; 12:7047. [PMID: 35487953 PMCID: PMC9054830 DOI: 10.1038/s41598-022-10973-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 04/15/2022] [Indexed: 12/18/2022] Open
Abstract
Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is a soluble form of TREM-1 released during inflammation. Elevated sTREM-1 levels have been found in neuropsychiatric systemic lupus erythematosus (NPSLE) patients; yet, the exact mechanisms remain unclear. This study investigated the role of sTREM-1 in brain damage and its underlying mechanism. The sTREM-1 recombinant protein (2.5 μg/3 μL) was injected into the lateral ventricle of C57BL/6 female mice. After intracerebroventricular (ICV) injection, the damage in hippocampal neurons increased, and the loss of neuronal synapses and activation of microglia increased compared to the control mice (treated with saline). In vitro. after sTREM-1 stimulation, the apoptosis of BV2 cells decreased, the polarization of BV2 cells shifted to the M1 phenotype, the phagocytic function of BV2 cells significantly improved, while the PI3K-AKT signal pathway was activated in vivo and in vitro. PI3K-AKT pathway inhibitor LY294002 reversed the excessive activation and phagocytosis of microglia caused by sTREM-1 in vivo and in vitro, which in turn improved the hippocampus damage. These results indicated that sTREM-1 activated the microglial by the PI3K-AKT signal pathway, and promoted its excessive phagocytosis of the neuronal synapse, thus inducing hippocampal damage. sTREM-1 might be a potential target for inducing brain lesions.
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Affiliation(s)
- Li Lu
- The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210093, People's Republic of China
| | - Xuan Liu
- The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210093, People's Republic of China
| | - Juanhua Fu
- The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210093, People's Republic of China
| | - Jun Liang
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, 210008, People's Republic of China.
| | - Yayi Hou
- The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China. .,Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210093, People's Republic of China.
| | - Huan Dou
- The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China. .,Jiangsu Key Laboratory of Molecular Medicine, Nanjing, 210093, People's Republic of China.
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19
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He C, Liu R, Fan Z, Li Y, Yang M, Wugang H, Lu Z, Fang Z, Su B. Microglia in the Pathophysiology of Hemorrhagic Stroke and the Relationship Between Microglia and Pain After Stroke: A Narrative Review. Pain Ther 2021; 10:927-939. [PMID: 34278548 PMCID: PMC8586130 DOI: 10.1007/s40122-021-00288-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/28/2021] [Indexed: 11/25/2022] Open
Abstract
Stroke is a leading cause of death worldwide, and about a quarter of stroke patients are dead within 1 month. The prognosis is even worse for those with hemorrhagic stroke because the 1-month mortality approaches 50%. Besides, most patients who survive experience complications such as nausea, vomiting, and chronic pain. These adverse experiences, especially the existence of chronic pain, can lead to a decline in the patient's quality of life. In order to improve the treatment and prognosis of hemorrhagic stroke, there is an urgent need to understand its pathophysiological mechanism as well as the chronic pain it induces. This paper reviews studies of the molecular mechanisms of hemorrhagic stroke, especially the activation of microglia and the relationship between microglia and pain after stroke, which could shed new light on hemorrhagic stroke treatment.
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Affiliation(s)
- Chen He
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Renhuai Liu
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Zhongming Fan
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Yi Li
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Manping Yang
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Hou Wugang
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Zhihong Lu
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Zongping Fang
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China.
| | - Binxiao Su
- Department of Critical Care Medicine and Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China.
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20
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Prednisolone induces osteocytes apoptosis by promoting Notum expression and inhibiting PI3K/AKT/GSK3β/β-catenin pathway. J Mol Histol 2021; 52:1081-1095. [PMID: 34297260 DOI: 10.1007/s10735-021-10006-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/16/2021] [Indexed: 12/15/2022]
Abstract
The apoptosis of mature osteocytes is the main factor causing damage to the microstructure of cortical bone in glucocorticoid-induced osteoporosis (GIOP). Our previous research found damaged areas and empty osteocytes lacunae in the tibial cortical bone of GIOP mice. However, the specific mechanism has not been clarified. Recently, a study showed that the quality of the cortical bone significantly increased by knocking out Notum, a gene encoding α/β hydrolase. However, it is not clear whether Notum affects cortical bone remodeling by participating in glucocorticoids (GCs)-induced apoptosis of osteocytes. The present study aimed to explore the correlation between Notum, osteocytes apoptosis, and cortical bone quality in GIOP. Prednisolone acetate was intragastrically administered to mice for two weeks. Histochemical staining was applied to evaluate changes in GIOP and Notum expression. Osteocytes were stimulated with prednisolone, and cell viability was assessed via CCK8. Hoechst 33342/PI staining, flow cytometry, RT-PCR, and western blot were used to detect osteocytes apoptosis, siRNA transfection efficiency, and expressions of pathway related factors. The results showed that the number of empty osteocytes lacunae increased in GIOP mice. TUNEL-stained apoptotic osteocytes and Notum immuno-positive osteocytes were also observed. Furthermore, prednisolone was found to promote Notum expression and osteocytes apoptosis in vitro. Knocking down Notum via siRNA partially restored osteocytes apoptosis and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β)/β-catenin pathway. These findings showed GCs-induced osteocytes apoptosis by promoting Notum expression and inhibiting PI3K/AKT/GSK3β/β-catenin pathway. Thus, Notum might be a potential therapeutic target for the treatment of GIOP.
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21
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Desale SE, Chidambaram H, Chinnathambi S. G-protein coupled receptor, PI3K and Rho signaling pathways regulate the cascades of Tau and amyloid-β in Alzheimer's disease. MOLECULAR BIOMEDICINE 2021; 2:17. [PMID: 35006431 PMCID: PMC8607389 DOI: 10.1186/s43556-021-00036-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/18/2021] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease is a progressive neurodegenerative disease characterized by the presence of amyloid-β plaques in the extracellular environment and aggregates of Tau protein that forms neurofibrillary tangles (NFTs) in neuronal cells. Along with these pathological proteins, the disease shows neuroinflammation, neuronal death, impairment in the immune function of microglia and synaptic loss, which are mediated by several important signaling pathways. The PI3K/Akt-mediated survival-signaling pathway is activated by many receptors such as G-protein coupled receptors (GPCRs), triggering receptor expressed on myeloid cells 2 (TREM2), and lysophosphatidic acid (LPA) receptor. The signaling pathway not only increases the survival of neurons but also regulates inflammation, phagocytosis, cellular protection, Tau phosphorylation and Aβ secretion as well. In this review, we focused on receptors, which activate PI3K/Akt pathway and its potential to treat Alzheimer's disease. Among several membrane receptors, GPCRs are the major drug targets for therapy, and GPCR signaling pathways are altered during Alzheimer's disease. Several GPCRs are involved in the pathogenic progression, phosphorylation of Tau protein by activation of various cellular kinases and are involved in the amyloidogenic pathway of amyloid-β synthesis. Apart from various GPCR signaling pathways, GPCR regulating/ interacting proteins are involved in the pathogenesis of Alzheimer's disease. These include several small GTPases, Ras homolog enriched in brain, GPCR associated sorting proteins, β-arrestins, etc., that play a critical role in disease progression and has been elaborated in this review.
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Affiliation(s)
- Smita Eknath Desale
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002 India
| | - Hariharakrishnan Chidambaram
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002 India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411008 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002 India
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22
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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.
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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
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23
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Weng Y, Wang H, Li L, Feng Y, Xu S, Wang Z. Trem2 mediated Syk-dependent ROS amplification is essential for osteoclastogenesis in periodontitis microenvironment. Redox Biol 2020; 40:101849. [PMID: 33486152 PMCID: PMC7823053 DOI: 10.1016/j.redox.2020.101849] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/04/2020] [Accepted: 12/24/2020] [Indexed: 12/20/2022] Open
Abstract
Periodontitis is the sixth most prevalent diseases around the globe, which is closely related to many systemic diseases and affects general health. As the leading cause of tooth loss, periodontitis is characterized by irreversible alveolar bone loss and activated osteoclastogenic process, which might be closely related to the activated intracellular reactive oxygen species (ROS) in osteoclasts. Here, we demonstrated triggering receptor expressed on myeloid cells 2 (Trem2) as a key regulator of osteoclastogenesis with the regulation of intracellular ROS signals in periodontitis. In the present study, the expression of Trem2 was significantly upregulated in human alveolar bones diagnosed with chronic periodontitis, as assessed by RNA-seq. In the mice model of periodontitis, the alveolar bone resorption was impeded in the presence of the conditional knockout of Trem2 in osteoclasts. Furthermore, we identified Trem2/DAP12/Syk-dependent cascade as a vital intracellular signaling for the amplification of reactive oxygen species (ROS) signals in osteoclastogenesis, while the accumulation of soluble Aβ42 oligomers (Aβo) in periodontitis microenvironment further strengthened the signals and enhanced osteoclastogenesis through direct interactions with Trem2. Collectively, Trem2 mediated ROS signal amplification cascade was crucial in the process of osteoclastogenesis in periodontitis, suggesting the potential of Trem2 as a target for the prevention and treatment of bone destruction in periodontitis.
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Affiliation(s)
- Yuteng Weng
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Haicheng Wang
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Lin Li
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Yanhuizhi Feng
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Shuyu Xu
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Zuolin Wang
- Department of Implantology, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China.
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24
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Liu LL, Cao ZH, He CL, Zhong YC, Liu WY, Zhang P, Yang F, Xu YJ. Ferric Ion Induction of Triggering Receptor Expressed in Myeloid Cells-2 Expression and PI3K/Akt Signaling Pathway in Preosteoclast Cells to Promote Osteoclast Differentiation. Orthop Surg 2020; 12:1304-1312. [PMID: 32729185 PMCID: PMC7454152 DOI: 10.1111/os.12750] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/24/2020] [Accepted: 06/18/2020] [Indexed: 12/16/2022] Open
Abstract
Objective Iron plays a significant role in multiple biological processes. The purpose of this study was to measure whether iron mediated osteoclast differentiation through regulation of triggering receptor expressed in myeloid cells‐2 (Trem‐2) expression and the PI3K/Akt signaling pathway. Methods The effects of six different concentrations of ferric ammonium citrate (FAC) (100, 80, 40, 20, 10 and 0 μmol/L) on RAW 264.7 cells proliferation were assessed by Cell Counting Kit‐8 (CCK‐8) gassay. Tartrate resistant acid phosphatase (TRAP) assay was performed to detect the effects of FAC on osteoclast formation. The expression of osteoclast differentiation‐related (TRAP, NFATc‐1, and c‐Fos) and Trem‐2 mRNA and proteins was analyzed by reverse transcription‐polymerase chain reaction and western blot, respectively. Si‐Trem‐2 was constructed and transfected to RAW264.7 to measure the effects of Trem‐2 on FAC‐mediated osteoclast formation. TRAP assay and osteoclast differentiation‐related gene analyses were further performed to identify the role of Trem‐2 in osteoclastogenesis. The Search Tool for the Retrieval of Interacting Genes (STRING) was used to explore the target genes of Trem‐2. Trem‐2‐related gene ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were used for further in‐depth analysis. PI3K/Akt pathway‐related proteins were detected by immunofluorescence and western blot. Results In groups with FAC concentration of 10 (102.5 ± 3.1), 20 (100.5 ± 1.5), and 40 μmol/L (98.7 ± 3.1), compared with the control group (100.1 ± 2.2), cell viability was not significantly different from the control (P > 0.05). When the concentration of FAC exceeded 80 μmol/L, cell viability was significantly decreased (87.5 ± 2.8 vs 100.1 ± 2.2, P < 0.05). FAC promotes Trem‐2 expression and osteoclast differentiation in a dose‐response manner (P < 0.05). The number of osteoclast‐like cells was found to be reduced following transfection with the siRNA of Trem‐2 (42 ± 3 vs 30 ± 5, P < 0.05). We observed that most of Trem‐2 target genes are primarily involved in response to organic substance, regulation of reactive oxygen species metabolic process, and regulation of protein phosphorylation. The STRING database revealed that Trem‐2 directly target two gene nodes (Pik3ca and Pik3r1), which are key transcriptional cofactors of the PI3K/Akt signaling pathway. KEGG pathways include the “PI3K‐Akt signaling pathway,” the “thyroid hormone signaling pathway”, “prostate cancer,” the “longevity regulating pathway,” and “insulin resistance.” Expression of p‐PI3K and p‐Akt protein, measured by immunofluorescence and western blotting, was markedly increased in the FAC groups. Trem‐2 siRNA caused partial reduction of these two proteins (p‐PI3K and p‐Akt) compared to the FAC alone group. Conclusion The FAC promoted osteoclast differentiation through the Trem‐2‐mediated PI3K/Akt signaling pathway. However, its regulation osteoclastogenesis should be verified through further in vivo studies.
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Affiliation(s)
- Lu-Lin Liu
- Department of Orthopaedics, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Department of Orthopaedics, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Zi-Hou Cao
- Department of Orthopaedics, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Chun-Lei He
- Department of Orthopaedics, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Yan-Chun Zhong
- Department of Orthopaedics, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Wu-Yang Liu
- Department of Orthopaedics, The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Peng Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Fan Yang
- Osteoporosis Institute of Soochow University, Suzhou, China
| | - You-Jia Xu
- Department of Orthopaedics, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Osteoporosis Institute of Soochow University, Suzhou, China
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25
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Schwabe T, Srinivasan K, Rhinn H. Shifting paradigms: The central role of microglia in Alzheimer's disease. Neurobiol Dis 2020; 143:104962. [PMID: 32535152 DOI: 10.1016/j.nbd.2020.104962] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 05/01/2020] [Accepted: 06/10/2020] [Indexed: 12/31/2022] Open
Abstract
Recent human genetic studies have challenged long standing hypotheses about the chain of events in Alzheimer's disease (AD), as the identification of genetic risk factors in microglial genes supports a causative role for microglia in the disease. Parallel transcriptome and histology studies at the single-cell level revealed a rich palette of microglial states affected by disease status and genetic risk factors. Taken together, those findings support microglia dysfunction as a central mechanism in AD etiology and thus the therapeutic potential of modulating microglial activity for AD treatment. Here we review how human genetic studies discovered microglial AD risk genes, such as TREM2, CD33, MS4A and APOE, and how experimental studies are beginning to decipher the cellular functions of some of these genes. Our review also focuses on recent transcriptomic studies of human microglia from postmortem tissue to critically assess areas of similarity and dissimilarity between human and mouse models currently in use in order to better understand the biology of innate immunity in AD.
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Chen S, Peng J, Sherchan P, Ma Y, Xiang S, Yan F, Zhao H, Jiang Y, Wang N, Zhang JH, Zhang H. TREM2 activation attenuates neuroinflammation and neuronal apoptosis via PI3K/Akt pathway after intracerebral hemorrhage in mice. J Neuroinflammation 2020; 17:168. [PMID: 32466767 PMCID: PMC7257134 DOI: 10.1186/s12974-020-01853-x] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 05/21/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Neuroinflammation is an important host defense response to secondary brain injury after intracerebral hemorrhage (ICH). Triggering receptor expressed on myeloid cells 2 (TREM2) confers strong neuroprotective effects by attenuating neuroinflammation in experimental ischemic stroke. Recent studies suggest that apolipoprotein E (apoE) is a novel, high-affinity ligand of TREM2. This study aimed to investigate the effects of TREM2 activation on neuroinflammation and neuronal apoptosis in a mouse model of ICH. METHODS Adult male CD1 mice (n = 216) were subjected to intrastriatal injection of bacterial collagenase. The TREM2 ligand, apoE-mimetic peptide COG1410 was administered intranasally at 1 h after ICH induction. To elucidate the underlying mechanism, TREM2 small interfering RNA (siRNA) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 were administered intracerebroventricularly prior to COG1410 treatment. Neurobehavioral tests, brain water content, immunofluorescence, western blotting, and Fluoro-Jade C- and terminal deoxynucleotidyl transferase dUTP nick end labeling staining were performed. RESULTS Endogenous TREM2 expression was increased and peaked at 24 h after ICH. TREM2 was expressed on microglia, astrocytes, and neurons. COG1410 improved both short-term and long-term neurological functions, reduced brain edema, inhibited microglia/macrophage activation and neutrophil infiltration, and suppressed neuronal apoptotic cell death in perihematomal areas after ICH. Knockdown of endogenous TREM2 by TREM2 siRNA aggravated neurological deficits and decreased the expression of TREM2 in naïve and ICH mice. COG1410 was associated with upregulation of TREM2, PI3K, phosphorylated-Akt, and Bcl-2 and downregulation of TNF-α, IL-1β, and Bax after ICH. The neuroprotective effects of COG1410 were abolished by both TREM2 siRNA and PI3K inhibitor LY294002. CONCLUSIONS Our finding demonstrated that TREM2 activation improved neurological functions and attenuated neuroinflammation and neuronal apoptosis after ICH, which was, at least in part, mediated by activation of PI3K/Akt signaling pathway. Therefore, activation of TREM2 may be a potential therapeutic strategy for the management of ICH patients.
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Affiliation(s)
- Shengpan Chen
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
- Department of Physiology and Pharmacology, Department of Neurosurgery and Anesthesiology, School of Medicine, Loma Linda University, Risley Hall, Room 219, 11041 Campus Street, Loma Linda, CA, 92354, USA
| | - Jianhua Peng
- Department of Physiology and Pharmacology, Department of Neurosurgery and Anesthesiology, School of Medicine, Loma Linda University, Risley Hall, Room 219, 11041 Campus Street, Loma Linda, CA, 92354, USA
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Prativa Sherchan
- Department of Physiology and Pharmacology, Department of Neurosurgery and Anesthesiology, School of Medicine, Loma Linda University, Risley Hall, Room 219, 11041 Campus Street, Loma Linda, CA, 92354, USA
| | - Yongjie Ma
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
| | - Sishi Xiang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
| | - Feng Yan
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
| | - Hao Zhao
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
| | - Yong Jiang
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
- Laboratory of Neurological Diseases and Brain Functions, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, Sichuan, China
| | - Ning Wang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China
| | - John H Zhang
- Department of Physiology and Pharmacology, Department of Neurosurgery and Anesthesiology, School of Medicine, Loma Linda University, Risley Hall, Room 219, 11041 Campus Street, Loma Linda, CA, 92354, USA.
- Department of Neurosurgery, Loma Linda University Medical Center, Loma Linda, CA, 92354, USA.
| | - Hongqi Zhang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China International Neuroscience Institute (China-INI), No. 45 Changchun Street, Xicheng District, Beijing, 10053, China.
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He GL, Luo Z, Shen TT, Wang ZZ, Li P, Luo X, Yang J, Tan YL, Wang Y, Gao P, Yang XS. TREM2 Regulates Heat Acclimation-Induced Microglial M2 Polarization Involving the PI3K-Akt Pathway Following EMF Exposure. Front Cell Neurosci 2020; 13:591. [PMID: 32009907 PMCID: PMC6974802 DOI: 10.3389/fncel.2019.00591] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/30/2019] [Indexed: 12/15/2022] Open
Abstract
The function of triggering receptor expressed on myeloid cells-2 (TREM2) has been described within microglia with a beneficial activated phenotype. However, the role of TREM2 underlying microglial phenotypic alterations in the cross-tolerance protection of heat acclimation (HA) against the inflammatory stimuli electromagnetic field (EMF) exposure is less well known. Here, we investigated the TREM2-related signaling mechanism induced by HA in EMF-stimulated N9 microglial cells (N9 cells). We found that EMF exposure significantly increased the production of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α, IL-1β, and IL-6), and the expression of M1 markers (CD11b and CD86); meanwhile, decreased the levels of anti-inflammatory cytokines (IL-4 and IL-10) and the expression of M2 markers (CD206 and Arg1) in N9 cells. Clearly, HA treatment decreased the secretion of TNF-α, IL-1β and IL-6 and the expression of CD11b and CD86, and enhanced the production of IL-4 and IL-10 and the expression of CD206 and Arg1. Moreover, TREM2 esiRNA and selective inhibitor of PI3K clearly decreased anti-inflammatory cytokines production, M2 markers expression, and phosphorylation of PI3K and Akt following HA plus EMF stimulation. These results indicate that TREM2 and PI3K-Akt pathway are involved in the cross-tolerance protective effect of HA in microglial polarization towards the EMF exposure. This finding inspires future studies that aim to explore the non-drug approaches underlying EMF stimulation and other central nervous system (CNS) inflammatory diseases.
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Affiliation(s)
- Gen-Lin He
- Department of Tropical Medicine, Army Medical University, Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
| | - Zhen Luo
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Ting-Ting Shen
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Ze-Ze Wang
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Ping Li
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Xue Luo
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Ju Yang
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Yu-Long Tan
- Department of Tropical Medicine, Army Medical University, Chongqing, China
| | - Yuan Wang
- Department of Nuclear Medicine, Xi'nan Hospital, Army Medical University, Chongqing, China
| | - Peng Gao
- Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education, Army Medical University, Chongqing, China
| | - Xue-Sen Yang
- Department of Tropical Medicine, Army Medical University, Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Army Medical University, Chongqing, China
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TREM2 acts as a tumor suppressor in hepatocellular carcinoma by targeting the PI3K/Akt/β-catenin pathway. Oncogenesis 2019; 8:9. [PMID: 30683932 PMCID: PMC6350080 DOI: 10.1038/s41389-018-0115-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 12/03/2018] [Accepted: 12/20/2018] [Indexed: 12/13/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is involved in nonmalignant pathological processes. However, TREM2’s function in malignant diseases, especially in hepatocellular carcinoma (HCC) remains unknown. In the present study, we report that TREM2 is a novel tumor suppressor in HCC. TREM2 expression was obviously decreased in hepatoma cells (especially metastatic HCC cells), and in most human HCC tissues (especially extrahepatic metastatic tumors). Reduced tumor TREM2 expression was correlated with poor prognosis of HCC patients, and with aggressive pathological features (BCLC stage, tumor size, tumor encapsulation, vascular invasion, and tumor differentiation). TREM2 knockdown substantially promoted cell growth, migration, and invasion in vitro and in vivo, while TREM2 overexpression produced the opposite effect. TREM2 suppressed HCC metastasis by inhibiting epithelial-mesenchymal transition, accompanied by abnormal expression of epithelial and mesenchymal markers. Further study revealed that downregulation of TREM2 in HCC was regulated by miR-31-5p. Moreover, by directly interacting with β-catenin, TREM2 attenuated oncogenic and metastatic behaviors by inhibiting Akt and GSK3β phosphorylation, and activating β-catenin. TREM2 suppressed carcinogenesis and metastasis in HCC by targeting the PI3K/Akt/β-catenin pathway. Thus, we propose that TREM2 may be a candidate prognostic biomarker in malignant diseases and TREM2 restoration might be a prospective strategy for HCC therapy.
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Up-Regulation of Trem2 Inhibits Hippocampal Neuronal Apoptosis and Alleviates Oxidative Stress in Epilepsy via the PI3K/Akt Pathway in Mice. Neurosci Bull 2019; 35:471-485. [PMID: 30684126 DOI: 10.1007/s12264-018-0324-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/01/2018] [Indexed: 01/03/2023] Open
Abstract
Epilepsy is a chronic and severe neurological disorder that has negative effects on the autonomous activities of patients. Functionally, Trem2 (triggering receptor expressed on myeloid cells-2) is an immunoglobulin receptor that affects neurological and psychiatric genetic diseases. Based on this rationale, we aimed to assess the potential role of Trem2 integration with the PI3K/Akt pathway in epilepsy. We used microarray-based gene expression profiling to identify epilepsy-related differentially-expressed genes. In a mouse hippocampal neuron model of epilepsy, neurons were treated with low-Mg2+ extracellular fluid, and the protein and mRNA expression of Trem2 were determined. Using a gain-of-function approach with Trem2, neuronal apoptosis and its related factors were assessed by flow cytometry, RT-qPCR, and Western blot analysis. In a pilocarpine-induced epileptic mouse model, the malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) content and superoxide dismutase (SOD) and glutathione-peroxidase (GSH-Px) activity in the hippocampus were determined, and the protein expression of Trem2 was measured. In addition, the regulatory effect of Trem2 on the PI3K/Akt pathway was analyzed by inhibiting this pathway in both the cell and mouse models of epilepsy. Trem2 was found to occupy a core position and was correlated with epilepsy. Trem2 was decreased in the hippocampus of epileptic mice and epileptic hippocampal neurons. Of crucial importance, overexpression of Trem2 activated the PI3K/Akt pathway to inhibit neuronal apoptosis. Moreover, activation of the PI3K/Akt pathway through over-expression of Trem2 alleviated oxidative stress, as shown by the increased expression of SOD and GSH-Px and the decreased expression of MDA and 8-OHdG. The current study defines the potential role of Trem2 in inhibiting the development of epilepsy, indicating that Trem2 up-regulation alleviates hippocampal neuronal injury and oxidative stress, and inhibits neuronal apoptosis in epilepsy by activating the PI3K/Akt pathway.
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Linnartz-Gerlach B, Bodea LG, Klaus C, Ginolhac A, Halder R, Sinkkonen L, Walter J, Colonna M, Neumann H. TREM2 triggers microglial density and age-related neuronal loss. Glia 2018; 67:539-550. [PMID: 30548312 PMCID: PMC6590266 DOI: 10.1002/glia.23563] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 12/22/2022]
Abstract
The microglial triggering receptor expressed on myeloid cells 2 (TREM2) signals via the activatory membrane adaptor molecule TYROBP. Genetic variants or mutations of TREM2 or TYROBP have been linked to inflammatory neurodegenerative diseases associated with aging. The typical aging process goes along with microglial changes and mild neuronal loss, but the exact contribution of TREM2 is still unclear. Aged TREM2 knock‐out mice showed decreased age‐related neuronal loss in the substantia nigra and the hippocampus. Transcriptomic analysis of the brains of 24 months old TREM2 knock‐out mice revealed 211 differentially expressed genes mostly downregulated and associated with complement activation and oxidative stress response pathways. Consistently, 24 months old TREM2 knock‐out mice showed lower transcription of microglial (Aif1 and Tmem119), oxidative stress markers (Inos, Cyba, and Cybb) and complement components (C1qa, C1qb, C1qc, C3, C4b, Itgam, and Itgb2), decreased microglial numbers and expression of the microglial activation marker Cd68, as well as accumulation of oxidized lipids. Cultured microglia of TREM2 knock‐out mice showed reduced phagocytosis and oxidative burst. Thus, microglial TREM2 contributes to age‐related microglial changes, phagocytic oxidative burst, and loss of neurons with possible detrimental effects during physiological aging.
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Affiliation(s)
- Bettina Linnartz-Gerlach
- Neural Regeneration, Institute of Reconstructive Neurobiology, University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Liviu-Gabriel Bodea
- Neural Regeneration, Institute of Reconstructive Neurobiology, University Hospital of Bonn, University of Bonn, Bonn, Germany.,Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, Queensland, Australia
| | - Christine Klaus
- Neural Regeneration, Institute of Reconstructive Neurobiology, University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Aurélien Ginolhac
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Rashi Halder
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Lasse Sinkkonen
- Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Jochen Walter
- Department of Neurology, University Bonn, Bonn, Germany
| | - Marco Colonna
- Washington University School of Medicine, Department of Pathology & Immunology, St. Louis, Missouri
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, University Hospital of Bonn, University of Bonn, Bonn, Germany
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31
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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.
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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
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32
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Wu Y, Li D, Wang Y, Liu X, Zhang Y, Qu W, Chen K, Francisco NM, Feng L, Huang X, Wu M. Beta-Defensin 2 and 3 Promote Bacterial Clearance of Pseudomonas aeruginosa by Inhibiting Macrophage Autophagy through Downregulation of Early Growth Response Gene-1 and c-FOS. Front Immunol 2018; 9:211. [PMID: 29487594 PMCID: PMC5816924 DOI: 10.3389/fimmu.2018.00211] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 01/24/2018] [Indexed: 01/08/2023] Open
Abstract
Beta-defensins 2 and 3 (BD2 and BD3) are inducible peptides present at the sites of infection, and they are well characterized for their antimicrobial activities and immune-regulatory functions. However, no study has thoroughly investigated their immunomodulatory effects on macrophage-mediated immune responses against Pseudomonas aeruginosa (PA). Here, we use THP-1 and RAW264.7 cell lines and demonstrate that BD2 and BD3 suppressed macrophage autophagy but enhanced the engulfment of PA and Zymosan bioparticles as well as the formation of phagolysosomes, using immunofluorescence staining and confocal microscopy. Plate count assay showed that macrophage-mediated phagocytosis and intracellular killing of PA were promoted by BD2 and BD3. Furthermore, microarray and real-time PCR showed that the expression of two genes, early growth response gene-1 (EGR1) and c-FOS, was attenuated by BD2 and BD3. Western blot revealed that BD2 and BD3 inhibited the expression and nuclear translocation of EGR1 and c-FOS. Knockdown of EGR1 and c-FOS by siRNA transfection suppressed macrophage autophagy before and after PA infection; while overexpression of these two transcription factors enhanced autophagy but reversed the role of BD2 and BD3 on macrophage-mediated PA eradication. Together, these results demonstrate a novel immune defense activity of BD2 and BD3, which promotes clearance of PA by inhibiting macrophage autophagy through downregulation of EGR1 and c-FOS.
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Affiliation(s)
- Yongjian Wu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Dandan Li
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Yi Wang
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Xi Liu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yuanqing Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wenting Qu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Kang Chen
- Division of Clinical Laboratory, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Ngiambudulu M Francisco
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Lianqiang Feng
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Xi Huang
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
| | - Minhao Wu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
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Ye P, Xu D, Xu J, Liu G, Huang S, Zhang W, Zheng P, Li J, Huang J. TREM-2 negatively regulates LPS-mediated inflammatory response in rat bone marrow-derived MSCs. Mol Med Rep 2017; 16:4777-4783. [PMID: 28849042 PMCID: PMC5647029 DOI: 10.3892/mmr.2017.7212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 07/27/2017] [Indexed: 12/19/2022] Open
Abstract
To the best of our knowledge, our previous study demonstrated the expression of triggering receptor expressed on myeloid cells 2 (TREM-2) in human bone marrow mesenchymal stem cells (MSCs) for the first time. However, the inflammation regulatory role of TREM-2 in MSCs remain elusive. The aim of the present study was to investigate the immune regulation and the underlying mechanism of TREM-2 in rat bone marrow MSCs. MSCs were divided into three groups: NullMSCs, TREM-2MSCs, and NormMSCs. TREM-2 was expressed in MSCs at the mRNA and protein level. Following stimulation by lipopolysaccharide (LPS), the gene transcription levels of TREM-2 and inflammatory cytokines were increased. The expression levels of inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in the TREM-2MSCs lentiviral vector group were significantly downregulated, and the expression of IL-10 was significantly upregulated compared with the controls. Western blot analysis revealed that TREM-2 downregulated the LPS-induced inflammatory response in MSCs, which was probably associated with regulating AKT serine/threonine kinase and p38 mitogen-activated protein kinase downstream signaling proteins. The results of the current study demonstrated that TREM-2 negatively regulates the LPS-mediated inflammatory response in MSCs suggesting that TREM-2 is a potential target of immune regulation in rat MSCs.
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Affiliation(s)
- Pei Ye
- Department of Orthopedics, Sun Yat‑sen Memorial Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Dawei Xu
- Department of Orthopedics, Sun Yat‑sen Memorial Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Jinhuang Xu
- Department of Orthopedics, Zengcheng People's Hospital of Guangzhou, Guangzhou, Guangdong 511300, P.R. China
| | - Guiwang Liu
- Department of Orthopedics, Sun Yat‑sen Memorial Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Shenghui Huang
- Department of Orthopedics, Sun Yat‑sen Memorial Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Weiqiong Zhang
- Department of Orthopedics, Zengcheng People's Hospital of Guangzhou, Guangzhou, Guangdong 511300, P.R. China
| | - Peizhong Zheng
- Department of Orthopedics, Zengcheng People's Hospital of Guangzhou, Guangzhou, Guangdong 511300, P.R. China
| | - Jianhua Li
- Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong 510182, P.R. China
| | - Jianrong Huang
- Department of Orthopedics, Sun Yat‑sen Memorial Hospital of Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
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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: 252] [Impact Index Per Article: 36.0] [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.
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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
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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: 145] [Impact Index Per Article: 20.7] [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.
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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.
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TREM2 Promotes Microglial Survival by Activating Wnt/β-Catenin Pathway. J Neurosci 2017; 37:1772-1784. [PMID: 28077724 DOI: 10.1523/jneurosci.2459-16.2017] [Citation(s) in RCA: 199] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/26/2016] [Accepted: 01/05/2017] [Indexed: 11/21/2022] Open
Abstract
Triggering Receptor Expressed on Myeloid cells 2 (TREM2), which is expressed on myeloid cells including microglia in the CNS, has recently been identified as a risk factor for Alzheimer's disease (AD). TREM2 transmits intracellular signals through its transmembrane binding partner DNAX-activating protein 12 (DAP12). Homozygous mutations inactivating TREM2 or DAP12 lead to Nasu-Hakola disease; however, how AD risk-conferring variants increase AD risk is not clear. To elucidate the signaling pathways underlying reduced TREM2 expression or loss of function in microglia, we respectively knocked down and knocked out the expression of TREM2 in in vitro and in vivo models. We found that TREM2 deficiency reduced the viability and proliferation of primary microglia, reduced microgliosis in Trem2-/- mouse brains, induced cell cycle arrest at the G1/S checkpoint, and decreased the stability of β-catenin, a key component of the canonical Wnt signaling pathway responsible for maintaining many biological processes, including cell survival. TREM2 stabilized β-catenin by inhibiting its degradation via the Akt/GSK3β signaling pathway. More importantly, treatment with Wnt3a, LiCl, or TDZD-8, which activates the β-catenin-mediated Wnt signaling pathway, rescued microglia survival and microgliosis in Trem2-/- microglia and/or in Trem2-/- mouse brain. Together, our studies demonstrate a critical role of TREM2-mediated Wnt/β-catenin pathway in microglial viability and suggest that modulating this pathway therapeutically may help to combat the impaired microglial survival and microgliosis associated with AD.SIGNIFICANCE STATEMENT Mutations in the TREM2 (Triggering Receptor Expressed on Myeloid cells 2) gene are associated with increased risk for Alzheimer's disease (AD) with effective sizes comparable to that of the apolipoprotein E (APOE) ε4 allele, making it imperative to understand the molecular pathway(s) underlying TREM2 function in microglia. Our findings shed new light on the relationship between TREM2/DNAX-activating protein 12 (DAP12) signaling and Wnt/β-catenin signaling and provide clues as to how reduced TREM2 function might impair microglial survival in AD pathogenesis. We demonstrate that TREM2 promotes microglial survival by activating the Wnt/β-catenin signaling pathway and that it is possible to restore Wnt/β-catenin signaling when TREM2 activity is disrupted or reduced. Therefore, we demonstrate the potential for manipulating the TREM2/β-catenin signaling pathway for the treatment of AD.
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Jiang H, Si Y, Li Z, Huang X, Chen S, Zheng Y, Xu G, Chen X, Chen Y, Liu Y, Xiong H, Huang Q, Liang M, Zhang Z. TREM-2 promotes acquired cholesteatoma-induced bone destruction by modulating TLR4 signaling pathway and osteoclasts activation. Sci Rep 2016; 6:38761. [PMID: 27934908 PMCID: PMC5146948 DOI: 10.1038/srep38761] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 11/07/2016] [Indexed: 02/08/2023] Open
Abstract
Triggering receptor expressed on myeloid cells (TREM) has been broadly studied in inflammatory disease. However, the expression and function of TREM-2 remain undiscovered in acquired cholesteatoma. The expression of TREM-2 was significantly higher in human acquired cholesteatoma than in normal skin from the external auditory canal, and its expression level was positively correlated with the severity of bone destruction. Furthermore, TREM-2 was mainly expressed on dendritic cells (DCs). In human acquired cholesteatoma, the expression of proinflammatory cytokines (IL-1β, TNF-α and IL-6) and matrix metalloproteinases (MMP-2, MMP-8 and MMP-9) were up-regulated, and their expression levels were positively correlated with TREM-2 expression. Osteoclasts were activated in human acquired cholesteatoma. In an animal model, TREM-2 was up-regulated in mice with experimentally acquired cholesteatoma. TREM-2 deficiency impaired the maturation of experimentally acquired cholesteatoma and protected against bone destruction induced by experimentally acquired cholesteatoma. Additional data showed that TREM-2 up-regulated IL-1β and IL-6 expression via TLR4 instead of the TLR2 signaling pathway and promoted MMP-2 and MMP-8 secretion and osteoclast activation in experimentally acquired cholesteatoma. Therefore, TREM-2 might enhance acquired cholesteatoma-induced bone destruction by amplifying the inflammatory response via TLR4 signaling pathways and promoting MMP secretion and osteoclast activation.
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Affiliation(s)
- Huaili Jiang
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Yu Si
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Zhuohao Li
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Xi Huang
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine and Key Laboratory of Tropical Diseases Control, Ministry of Education Sun Yat-sen University, Guangzhou, China
| | - Suijun Chen
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Yiqing Zheng
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Guo Xu
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Ximing Chen
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Yubin Chen
- Department of Otolaryngology Head and Neck Surgery, The third affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yi Liu
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Hao Xiong
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Qiuhong Huang
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Maojin Liang
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
| | - Zhigang Zhang
- Department of Otolaryngology Head and Neck Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, China
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Zhang H, Sheng L, Tao J, Chen R, Li Y, Sun Z, Qian W. Depletion of the triggering receptor expressed on myeloid cells 2 inhibits progression of renal cell carcinoma via regulating related protein expression and PTEN-PI3K/Akt pathway. Int J Oncol 2016; 49:2498-2506. [PMID: 27779645 DOI: 10.3892/ijo.2016.3740] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/03/2016] [Indexed: 11/05/2022] Open
Abstract
The triggering receptor expressed on myeloid cells 2 (TREM-2) is suggested to be involved in the development of certain human malignancies. However, the functions of TREM-2 in renal cell carcinoma (RCC) are still less known. To reveal the effects of TREM-2 on the RCC progression, we examined the TREM-2 expression in RCC tumor tissues. Then, we analyzed the cell proliferation, cell apoptosis, cell cycle and expression of the relative factors in two selected RCC cell lines post RNA interference. We also analyzed the functions of TREM-2 in an in vivo nude mouse model. We found that, the expression of TREM-2 was abnormally elevated in RCC tumor tissues. Silencing TREM-2 inhibited cell growth, induced G1 phase arrest of cell cycle and cell apoptosis in RCC cells. In vivo, the results showed that depletion of TREM-2 significantly inhibited the ACHN tumor growth in the nude mouse model. The analysis of relative protein factors suggested that silencing TREM-2 downregulated the expression levels of Bcl2 and PCNA, and upregulated the expression levels of Bax and caspase-3 in RCC cell lines. Depletion of TREM-2 inactivated PI3K/Akt pathway through increasing the expression of PTEN. Taken together, TREM-2 acts as an oncogene in the development of RCC and can be considered as a novel therapeutic factor in the treatment of RCC.
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Affiliation(s)
- Haojie Zhang
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
| | - Lu Sheng
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
| | - Jing Tao
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
| | - Ran Chen
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
| | - Yang Li
- Department of Biology, School of Life Science, Anhui Medical University, Hefei, Anhui, P.R. China
| | - Zhongquan Sun
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
| | - Weiqing Qian
- Department of Urology, Huadong Hospital, Fudan University, Shanghai, P.R. China
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Wu Y, Li D, Wang Y, Chen K, Yang K, Huang X, Zhang Y, Wu M. Pseudomonas aeruginosa promotes autophagy to suppress macrophage-mediated bacterial eradication. Int Immunopharmacol 2016; 38:214-22. [PMID: 27295610 DOI: 10.1016/j.intimp.2016.04.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/12/2016] [Accepted: 04/29/2016] [Indexed: 12/15/2022]
Abstract
OBJECTIVES To explore the role of autophagy on macrophage-mediated phagocytosis and intracellular killing of Pseudomonas aeruginosa (PA), a common extracellular bacterium which often causes various opportunistic infections. METHODS Macrophages were infected with PA or stimulated with zymosan bioparticles. Autophagy was tested by fluorescent microscopy and Western blot for LC3. Phagocytosis and killing efficiency were assessed by plate count assay, flow cytometry or immunofluorescent staining. Phagocytic receptor expression, ROS generation and NO production were examined by PCR, flow cytometry and Griess reaction, respectively. RESULTS PA infection induced autophagy activation in both mouse and human macrophages. Induction of autophagy by rapamycin or starvation significantly inhibited PA internalization by downregulating phagocytosis receptor expression, and suppressed intracellular killing of PA via reducing ROS and NO production in macrophages. While knockdown of autophagy molecules ATG7 or Beclin1 enhanced macrophage-mediated phagocytosis and intracellular killing of PA. Additionally, confocal microscopy data showed that induction of autophagy reduced the number of phagosomes and phagolysosomes in macrophages after stimulation with zymosan bioparticles. CONCLUSIONS Our study suggested that PA promotes autophagy to suppress macrophage-mediated bacterial phagocytosis and intracellular killing. These insights demonstrated a novel immune evasion mechanism employed by PA, which may provide potential therapeutic strategies of PA infectious diseases.
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Affiliation(s)
- Yongjian Wu
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Dandan Li
- Department of Clinical Laboratory, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 243000, China
| | - Yi Wang
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Kang Chen
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China; Division of Clinical Laboratory, Zhongshan Hospital of Sun Yat-sen University, Zhongshan 528403, China
| | - Kun Yang
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Xi Huang
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Yuanqing Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
| | - Minhao Wu
- Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China.
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Yang K, Wu Y, Xie H, Li M, Ming S, Li L, Li M, Wu M, Gong S, Huang X. Macrophage-mediated inflammatory response decreases mycobacterial survival in mouse MSCs by augmenting NO production. Sci Rep 2016; 6:27326. [PMID: 27251437 PMCID: PMC4890015 DOI: 10.1038/srep27326] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 05/12/2016] [Indexed: 12/28/2022] Open
Abstract
Mycobacterium tuberculosis (MTB) is a hard-to-eradicate intracellular microbe, which escapes host immune attack during latent infection. Recent studies reveal that mesenchymal stem cells (MSCs) provide a protective niche for MTB to maintain latency. However, the regulation of mycobacterial residency in MSCs in the infectious microenvironment remains largely unknown. Here, we found that macrophage-mediated inflammatory response during MTB infection facilitated the clearance of bacilli residing in mouse MSCs. Higher inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production were observed in mouse MSCs under macrophage-mediated inflammatory circumstance. Blocking NO production in MSCs increased the survival of intracellular mycobacteria, indicating NO-mediated antimycobacterial activity. Moreover, both nuclear factor κB (NF-κB) and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways were involved in iNOS expression and NO production in inflammatory microenvironment. Furthermore, pro-inflammatory cytokine interleukin-1β could trigger NO production in MSCs and exert anti-mycobacterial activity via NF-κB signaling pathway. Neutralization of interleukin-1β in macrophage-mediated inflammatory microenvironment dampened the ability of mouse MSCs to produce NO. Together, our findings demonstrated that macrophage-mediated inflammatory response during mycobacterial infection promotes the clearance of bacilli in mouse MSCs by increasing NO production, which may provide a better understanding of latent MTB infection.
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Affiliation(s)
- Kun Yang
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Yongjian Wu
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Heping Xie
- Department of Traditional Chinese Medicine, Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China
| | - Miao Li
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Siqi Ming
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Liyan Li
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Meiyu Li
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Minhao Wu
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Sitang Gong
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Xi Huang
- Program of Immunology, Affiliated Guangzhou Women and Children's Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.,Institute of Tuberculosis Control, Key laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
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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.
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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
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Deng Q, Wang Y, Zhang Y, Li M, Li D, Huang X, Wu Y, Pu J, Wu M. Pseudomonas aeruginosa Triggers Macrophage Autophagy To Escape Intracellular Killing by Activation of the NLRP3 Inflammasome. Infect Immun 2016; 84:56-66. [PMID: 26467446 PMCID: PMC4694000 DOI: 10.1128/iai.00945-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/12/2015] [Indexed: 02/07/2023] Open
Abstract
Assembly of the inflammasome has recently been identified to be a critical event in the initiation of inflammation. However, its role in bacterial killing remains unclear. Our study demonstrates that Pseudomonas aeruginosa infection induces the assembly of the NLRP3 inflammasome and the sequential secretion of caspase1 and interleukin-1β (IL-1β) in human macrophages. More importantly, activation of the NLRP3 inflammasome reduces the killing of P. aeruginosa in human macrophages, without affecting the generation of antimicrobial peptides, reactive oxygen species, and nitric oxide. In addition, our results demonstrate that P. aeruginosa infection increases the amount of the LC3-II protein and triggers the formation of autophagosomes in human macrophages. The P. aeruginosa-induced autophagy was enhanced by overexpression of NLRP3, ASC, or caspase1 but was reduced by knockdown of these core molecules of the NLRP3 inflammasome. Treatment with IL-1β enhanced autophagy in human macrophages. More importantly, IL-1β decreased the macrophage-mediated killing of P. aeruginosa, whereas knockdown of ATG7 or Beclin1 restored the IL-1β-mediated suppression of bacterial killing. Collectively, our study explores a novel mechanism employed by P. aeruginosa to escape from phagocyte killing and may provide a better understanding of the interaction between P. aeruginosa and host immune cells, including macrophages.
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Affiliation(s)
- Qiuchan Deng
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yi Wang
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yuanqing Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Meiyu Li
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Dandan Li
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Xi Huang
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yongjian Wu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jieying Pu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Minhao Wu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
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Li Y, Wu S, Pu J, Huang X, Zhang P. Dengue virus up-regulates expression of notch ligands Dll1 and Dll4 through interferon-β signalling pathway. Immunology 2015; 144:127-38. [PMID: 25041739 DOI: 10.1111/imm.12357] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/05/2014] [Accepted: 07/08/2014] [Indexed: 12/13/2022] Open
Abstract
The Notch signalling pathway is involved in multiple cellular processes and has been recently indicated to modulate the host immune response. However, the role of the Notch pathway in dengue virus (DENV) infection remains unknown. Our study has screened the expression profile of Notch receptors, ligands and target genes in human monocytes, macrophages and dendritic cells in response to DENV infection. The real-time PCR data showed that Notch ligand Dll1 was significantly induced in DENV-infected monocytes; and receptor Notch4, ligands Dll1 and Dll4, and target Hes1 were dramatically enhanced in DENV-infected macrophages and dendritic cells. In macrophages, induction of Dll1 and Dll4 mediated by DENV2 was increased by treatment with interferon-β (IFN-β), and was impaired by neutralization of IFN-β. The DENV-induced Dll1 and Dll4 expression level was decreased by silencing key innate immune molecules, including Toll-like receptor 3 (TLR3), MyD88, RIG-I and IPS-I. In IFN-receptor-depleted macrophages, the Dll1 and Dll4 induction was significantly alleviated. Functionally, activation of Notch signalling by Dll1 in CD4(+) T cells enhanced the expression of a T helper type 1 (Th1) cytokine IFN-γ, while Notch activation in macrophages had no direct effect on replication of DENV. Our data revealed that the expressions of Notch ligands in antigen-presenting cells were differentially induced by DENV via innate immune signalling, which is important for Th1/Th2 differentiation during adaptive immune response.
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Affiliation(s)
- Yuye Li
- Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China; Key Laboratory of Tropical Diseases Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China
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Wei P, Lu Q, Cui G, Guan Z, Yang L, Sun C, Sun W, Peng Q. The role of TREM-2 in internalization and intracellular survival of Brucella abortus in murine macrophages. Vet Immunol Immunopathol 2014; 163:194-201. [PMID: 25563793 DOI: 10.1016/j.vetimm.2014.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 12/11/2022]
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM-2) is a cell surface receptor primarily expressed on macrophages and dendritic cells. TREM-2 functions as a phagocytic receptor for bacteria as well as an inhibitor of Toll like receptors (TLR) induced inflammatory cytokines. However, the role of TREM-2 in Brucella intracellular growth remains unknown. To investigate whether TREM-2 is involved in Brucella intracellular survival, we chose bone marrow derived macrophages (BMDMs), in which TREM-2 is stably expressed, as cell model. Colony formation Units (CFUs) assay suggests that TREM-2 is involved in the internalization of Brucella abortus (B. abortus) by macrophages, while silencing of TREM-2 decreases intracellular survival of B. abortus. To further study the underlying mechanisms of TREM-2-mediated bacterial intracellular survival, we examined the activation of B. abortus-infected macrophages through determining the kinetics of activation of the three MAPKs, including ERK, JNK and p38, and measuring TNFα production in response to lipopolysaccharide (LPS) of Brucella (BrLPS) or B. abortus stimulation. Our data show that TREM-2 deficiency promotes activation of Brucella-infected macrophages. Moreover, our data also demonstrate that macrophage activation promotes killing of Brucella by enhancing nitric oxygen (NO), but not reactive oxygen species (ROS) production, macrophage apoptosis or cellular death. Taken together, these findings provide a novel interpretation of Brucella intracellular growth through inhibition of NO production produced by TREM-2-mediated activated macrophages.
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Affiliation(s)
- Pan Wei
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Qiang Lu
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Guimei Cui
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Zhenhong Guan
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Li Yang
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Changjiang Sun
- College of Veterinary Medicine, Jilin University, Changchun, People's Republic of China
| | - Wanchun Sun
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China
| | - Qisheng Peng
- Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, People's Republic of China.
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