1
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Ni J, Xie Z, Quan Z, Meng J, Qing H. How brain 'cleaners' fail: Mechanisms and therapeutic value of microglial phagocytosis in Alzheimer's disease. Glia 2024; 72:227-244. [PMID: 37650384 DOI: 10.1002/glia.24465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/10/2023] [Accepted: 08/19/2023] [Indexed: 09/01/2023]
Abstract
Microglia are the resident phagocytes of the brain, where they primarily function in the clearance of dead cells and the removal of un- or misfolded proteins. The impaired activity of receptors or proteins involved in phagocytosis can result in enhanced inflammation and neurodegeneration. RNA-seq and genome-wide association studies have linked multiple phagocytosis-related genes to neurodegenerative diseases, while the knockout of such genes has been demonstrated to exert protective effects against neurodegeneration in animal models. The failure of microglial phagocytosis influences AD-linked pathologies, including amyloid β accumulation, tau propagation, neuroinflammation, and infection. However, a precise understanding of microglia-mediated phagocytosis in Alzheimer's disease (AD) is still lacking. In this review, we summarize current knowledge of the molecular mechanisms involved in microglial phagocytosis in AD across a wide range of pre-clinical, post-mortem, ex vivo, and clinical studies and review the current limitations regarding the detection of microglia phagocytosis in AD. Finally, we discuss the rationale of targeting microglial phagocytosis as a therapeutic strategy for preventing AD or slowing its progression.
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Affiliation(s)
- Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhen Xie
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhenzhen Quan
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jie Meng
- Department of Geriatrics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
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2
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Birkle TJY, Brown GC. Syk inhibitors protect against microglia-mediated neuronal loss in culture. Front Aging Neurosci 2023; 15:1120952. [PMID: 37009452 PMCID: PMC10050448 DOI: 10.3389/fnagi.2023.1120952] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 02/28/2023] [Indexed: 03/17/2023] Open
Abstract
Microglia are brain macrophages and play beneficial and/or detrimental roles in many brain pathologies because of their inflammatory and phagocytic activity. Microglial inflammation and phagocytosis are thought to be regulated by spleen tyrosine kinase (Syk), which is activated by multiple microglial receptors, including TREM2 (Triggering Receptor Expressed on Myeloid Cells 2), implicated in neurodegeneration. Here, we have tested whether Syk inhibitors can prevent microglia-dependent neurodegeneration induced by lipopolysaccharide (LPS) in primary neuron-glia cultures. We found that the Syk inhibitors BAY61-3606 and P505-15 (at 1 and 10 μM, respectively) completely prevented the neuronal loss induced by LPS, which was microglia-dependent. Syk inhibition also prevented the spontaneous loss of neurons from older neuron-glia cultures. In the absence of LPS, Syk inhibition depleted microglia from the cultures and induced some microglial death. However, in the presence of LPS, Syk inhibition had relatively little effect on microglial density (reduced by 0-30%) and opposing effects on the release of two pro-inflammatory cytokines (IL-6 decreased by about 45%, TNFα increased by 80%). Syk inhibition also had no effect on the morphological transition of microglia exposed to LPS. On the other hand, inhibition of Syk reduced microglial phagocytosis of beads, synapses and neurons. Thus, Syk inhibition in this model is most likely neuroprotective by reducing microglial phagocytosis, however, the reduced microglial density and IL-6 release may also contribute. This work adds to increasing evidence that Syk is a key regulator of the microglial contribution to neurodegenerative disease and suggests that Syk inhibitors may be used to prevent excessive microglial phagocytosis of synapses and neurons.
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Affiliation(s)
| | - Guy C. Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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3
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The Pathological Activation of Microglia Is Modulated by Sexually Dimorphic Pathways. Int J Mol Sci 2023; 24:ijms24054739. [PMID: 36902168 PMCID: PMC10003784 DOI: 10.3390/ijms24054739] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/11/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Microglia are the primary immunocompetent cells of the central nervous system (CNS). Their ability to survey, assess and respond to perturbations in their local environment is critical in their role of maintaining CNS homeostasis in health and disease. Microglia also have the capability of functioning in a heterogeneous manner depending on the nature of their local cues, as they can become activated on a spectrum from pro-inflammatory neurotoxic responses to anti-inflammatory protective responses. This review seeks to define the developmental and environmental cues that support microglial polarization towards these phenotypes, as well as discuss sexually dimorphic factors that can influence this process. Further, we describe a variety of CNS disorders including autoimmune disease, infection, and cancer that demonstrate disparities in disease severity or diagnosis rates between males and females, and posit that microglial sexual dimorphism underlies these differences. Understanding the mechanism behind differential CNS disease outcomes between men and women is crucial in the development of more effective targeted therapies.
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4
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Wu C, Jiang ML, Jiang R, Pang T, Zhang CJ. The roles of fungus in CNS autoimmune and neurodegeneration disorders. Front Immunol 2023; 13:1077335. [PMID: 36776399 PMCID: PMC9910218 DOI: 10.3389/fimmu.2022.1077335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/30/2022] [Indexed: 01/28/2023] Open
Abstract
Fungal infection or proliferation in our body is capable of initiation of strong inflammation and immune responses that result in different consequences, including infection-trigged organ injury and inflammation-related remote organ dysfunction. Fungi associated infectious diseases have been well recognized in the clinic. However, whether fungi play an important role in non-infectious central nervous system disease is still to be elucidated. Recently, a growing amount of evidence point to a non-negligible role of peripheral fungus in triggering unique inflammation, immune response, and exacerbation of a range of non-infectious CNS disorders, including Multiple sclerosis, Neuromyelitis optica, Parkinson's disease, Alzheimer's disease, and Amyotrophic lateral sclerosis et al. In this review, we summarized the recent advances in recognizing patterns and inflammatory signaling of fungi in different subsets of immune cells, with a specific focus on its function in CNS autoimmune and neurodegeneration diseases. In conclusion, the fungus is capable of triggering unique inflammation by multiple mechanisms in the progression of a body of CNS non-infectious diseases, suggesting it serves as a key factor and critical novel target for the development of potential therapeutic strategies.
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Affiliation(s)
- Chuyu Wu
- Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China,State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Screening, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, China
| | - Mei-Ling Jiang
- Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China,*Correspondence: Cun-Jin Zhang, ; Mei-Ling Jiang, ; Tao Pang,
| | - Runqui Jiang
- Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Tao Pang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Screening, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, China,*Correspondence: Cun-Jin Zhang, ; Mei-Ling Jiang, ; Tao Pang,
| | - Cun-Jin Zhang
- Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China,Department of Neurology, Nanjing Drum Tower Hospital, Medical School and the State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University of Chinese Medicine, Nanjing University, Nanjing, Jiangsu, China,Institute of Brain Sciences, Institute of Brain Disorder Translational Medicine, Nanjing University, Nanjing, Jiangsu, China,Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, Jiangsu, China,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, Jiangsu, China,*Correspondence: Cun-Jin Zhang, ; Mei-Ling Jiang, ; Tao Pang,
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5
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Portugal CC, Almeida TO, Socodato R, Relvas JB. Src family kinases (SFKs): critical regulators of microglial homeostatic functions and neurodegeneration in Parkinson's and Alzheimer's diseases. FEBS J 2022; 289:7760-7775. [PMID: 34510775 DOI: 10.1111/febs.16197] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 08/03/2021] [Accepted: 09/10/2021] [Indexed: 01/14/2023]
Abstract
c-Src was the first protein kinase to be described as capable of phosphorylating tyrosine residues. Subsequent identification of other tyrosine-phosphorylating protein kinases with a similar structure to c-Src gave rise to the concept of Src family kinases (SFKs). Microglia are the resident innate immune cell population of the CNS. Under physiological conditions, microglia actively participate in brain tissue homeostasis, continuously patrolling the neuronal parenchyma and exerting neuroprotective actions. Activation of pathogen-associated molecular pattern (PAMP) and damage-associated molecular pattern (DAMP) receptors induces microglial proliferation, migration toward pathological foci, phagocytosis, and changes in gene expression, concurrent with the secretion of cytokines, chemokines, and growth factors. A significant body of literature shows that SFK stimulation positively associates with microglial activation and neuropathological conditions, including Alzheimer's and Parkinson's diseases. Here, we review essential microglial homeostatic functions regulated by SFKs, including phagocytosis, environmental sensing, and secretion of inflammatory mediators. In addition, we discuss the potential of SFK modulation for microglial homeostasis in Parkinson's and Alzheimer's diseases.
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Affiliation(s)
- Camila C Portugal
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Portugal
| | - Tiago O Almeida
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Portugal.,Doutoramento em Ciências Biomédicas, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Portugal
| | - Renato Socodato
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Portugal
| | - João B Relvas
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Portugal.,Department of Biomedicine, Faculty of Medicine, University of Porto, Portugal
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6
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Cryptococcus neoformans Infection in the Central Nervous System: The Battle between Host and Pathogen. J Fungi (Basel) 2022; 8:jof8101069. [PMID: 36294634 PMCID: PMC9605252 DOI: 10.3390/jof8101069] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 10/07/2022] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans (C. neoformans) is a pathogenic fungus with a global distribution. Humans become infected by inhaling the fungus from the environment, and the fungus initially colonizes the lungs. If the immune system fails to contain C. neoformans in the lungs, the fungus can disseminate to the blood and invade the central nervous system, resulting in fatal meningoencephalitis particularly in immunocompromised individuals including HIV/AIDS patients. Following brain invasion, C. neoformans will encounter host defenses involving resident as well as recruited immune cells in the brain. To overcome host defenses, C. neoformans possesses multiple virulence factors capable of modulating immune responses. The outcome of the interactions between the host and C. neoformans will determine the disease progression. In this review, we describe the current understanding of how C. neoformans migrates to the brain across the blood–brain barrier, and how the host immune system responds to the invading organism in the brain. We will also discuss the virulence factors that C. neoformans uses to modulate host immune responses.
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7
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Tan Y, Xiong M, Liu Q, Yin Y, Yin X, Liao S, Wang Y, Hu L, Zhang XB. Precisely controlling the cellular internalization of DNA-decorated semiconductor polymer nanoparticles for drug delivery. RSC Adv 2022; 12:31173-31179. [DOI: 10.1039/d2ra05172a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022] Open
Abstract
Precisely controlling the cellular internalization of DNA-decorated semiconductor polymer nanoparticles (SPN-DNA) for drug delivery based on the minimized nonspecific adhesivity to cells.
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Affiliation(s)
- Ying Tan
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Mengyi Xiong
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Qin Liu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Yao Yin
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Xia Yin
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Shiyi Liao
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Youjuan Wang
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Ling Hu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
| | - Xiao-Bing Zhang
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha 41008, P. R. China
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8
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Illouz T, Nicola R, Ben-Shushan L, Madar R, Biragyn A, Okun E. Maternal antibodies facilitate Amyloid-β clearance by activating Fc-receptor-Syk-mediated phagocytosis. Commun Biol 2021; 4:329. [PMID: 33712740 PMCID: PMC7955073 DOI: 10.1038/s42003-021-01851-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 02/11/2021] [Indexed: 02/07/2023] Open
Abstract
Maternal antibodies (MAbs) protect against infections in immunologically-immature neonates. Maternally transferred immunity may also be harnessed to target diseases associated with endogenous protein misfolding and aggregation, such as Alzheimer's disease (AD) and AD-pathology in Down syndrome (DS). While familial early-onset AD (fEOAD) is associated with autosomal dominant mutations in the APP, PSEN1,2 genes, promoting cerebral Amyloid-β (Aβ) deposition, DS features a life-long overexpression of the APP and DYRK1A genes, leading to a cognitive decline mediated by Aβ overproduction and tau hyperphosphorylation. Although no prenatal screening for fEOAD-related mutations is in clinical practice, DS can be diagnosed in utero. We hypothesized that anti-Aβ MAbs might promote the removal of early Aβ accumulation in the central nervous system of human APP-expressing mice. To this end, a DNA-vaccine expressing Aβ1-11 was delivered to wild-type female mice, followed by mating with 5xFAD males, which exhibit early Aβ plaque formation. MAbs reduce the offspring's cortical Aβ levels 4 months after antibodies were undetectable, along with alleviating short-term memory deficits. MAbs elicit a long-term shift in microglial phenotype in a mechanism involving activation of the FcγR1/Syk/Cofilin pathway. These data suggest that maternal immunization can alleviate cognitive decline mediated by early Aβ deposition, as occurs in EOAD and DS.
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Affiliation(s)
- Tomer Illouz
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's disease research, Bar-Ilan University, Ramat Gan, Israel
| | - Raneen Nicola
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's disease research, Bar-Ilan University, Ramat Gan, Israel
| | - Linoy Ben-Shushan
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's disease research, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman faculty of Life sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Ravit Madar
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- The Paul Feder Laboratory on Alzheimer's disease research, Bar-Ilan University, Ramat Gan, Israel
- The Mina and Everard Goodman faculty of Life sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Arya Biragyn
- Immunoregulation Section, Laboratory of Immunology and Molecular Biology, National Institute on Aging, Baltimore, MD, USA
| | - Eitan Okun
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
- The Paul Feder Laboratory on Alzheimer's disease research, Bar-Ilan University, Ramat Gan, Israel.
- The Mina and Everard Goodman faculty of Life sciences, Bar-Ilan University, Ramat Gan, Israel.
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9
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Moriuchi Y, Iwagawa T, Tsuhako A, Koso H, Fujita Y, Watanabe S. RasV12 Expression in Microglia Initiates Retinal Inflammation and Induces Photoreceptor Degeneration. Invest Ophthalmol Vis Sci 2020; 61:34. [PMID: 33231622 PMCID: PMC7691791 DOI: 10.1167/iovs.61.13.34] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 11/05/2020] [Indexed: 12/04/2022] Open
Abstract
Purpose The role of activated retinal microglia in driving retinal degeneration has been implicated in a number of in vivo disease models. Here, we investigated the primary consequences of microglial activation by the specific expression of constitutively active Ras in microglia in a transgenic mouse model before the onset of any degenerative changes in the retina. Methods The double transgenic lines CAG-LSL-RasV12-IRES-EGFP; Cx3cr1CreER/+ (Cx3cr1-RasV12 mice) and CAG-LSL-EGFP; Cx3cr1CreER_+ (control mice) were generated. The expression of RasV12 was induced in microglia by tamoxifen administration, and the retinas were examined by immunohistochemistry of frozen sections, RT-qPCR, and live imaging. Results RasV12 expression in retinal microglial cells promoted cell proliferation, cytokine expression, and phagocytosis. RasV12-expressing microglia migrated toward the inner and outer layers of the retina. Examination of glial fibrillary acidic protein (GFAP) expression revealed activation of Müller glia in the retina. We also observed loss of the photoreceptors in the outer nuclear layer in close proximity to microglial cells. However, no significant neurodegeneration was detected in the inner nuclear layer (INL) or ganglion cell layer (GCL). The morphology of RasV12-expressing microglia in the GCL and INL retained more ramified features compared with the predominantly-ameboid morphology found in outer retinal microglia. Conclusions The expression of RasV12 is sufficient to activate microglia and lead to photoreceptor degeneration. Neurons in the inner side of the retina were not damaged by the RasV12-activated microglia, suggesting that microenvironment cues may modulate the microglial phenotypic features and effects of microglial activation.
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Affiliation(s)
- Yuta Moriuchi
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Toshiro Iwagawa
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Asano Tsuhako
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Hideto Koso
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Yasuyuki Fujita
- Department of Molecular Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
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10
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Rahimi-Balaei M, Jiao X, Dalvand A, Shabanipour S, Chung SH, Amiri S, Kong J, Marzban H. Mutations in the Reelin pathway are associated with abnormal expression of microglial IgG FC receptors in the cerebellar cortex. Mol Biol Rep 2020; 47:5323-5331. [PMID: 32594343 DOI: 10.1007/s11033-020-05614-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/20/2020] [Indexed: 11/29/2022]
Abstract
Microglia are the immune cells of the central nervous system involved in a variety of developmental processes, such as regulation of cell death and survival, spatial patterning, and contribute to the development of Purkinje cells (PCs) during migration. Microglia express immunoglobulin G Fc receptors (FcgRs). In this report, we describe microglial FcgR expression and its relation to abnormal PC migration in the cerebellum during development. To detect microglial FcgR, the direct anti-IgG (secondary antisera) and high concentrations of Triton X-100 were applied as a method for labeling microglial cells without the use of any specific primary antiserum. By using Acp2-/- mice, which show an excessive PC migration into the molecular layer (ml), and 3 different types of mice with a null to alter the Reelin pathway (Reeler-, Dab1 (SCM)-, and Apoer mutant mice), we studied the location of PCs and the expression of FcgRs. Wild type littermates were used as controls in all studies. We show that the expression of microglial FcgRs was absent and PCs were ectopically located in the white matter in the cerebella of all mutant mice, except for the Acp2-/- mice (PCs were located in the ml). These results suggest a role for FcgRs in the Reelin signaling pathway, not in regulating PC migration, but rather in the adaptation to an environment with a relatively large number of ectopically located PCs. However, the exact correlation between the ectopic location of PCs and lack of FcgRs in Reeler, SCM, and Apoer-/- mice and the presence of FcgRs and directed PC location in the ml in Acp2-/- mice are yet to be determined.
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Affiliation(s)
- Maryam Rahimi-Balaei
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.,The Children's Hospital Research Institute of Manitoba (CHRIM), Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Xiaodan Jiao
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Azadeh Dalvand
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Shahin Shabanipour
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Seung H Chung
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Shayan Amiri
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Jimig Kong
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Hassan Marzban
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada. .,The Children's Hospital Research Institute of Manitoba (CHRIM), Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.
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11
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Karnam A, Rambabu N, Das M, Bou-Jaoudeh M, Delignat S, Käsermann F, Lacroix-Desmazes S, Kaveri SV, Bayry J. Therapeutic normal IgG intravenous immunoglobulin activates Wnt-β-catenin pathway in dendritic cells. Commun Biol 2020; 3:96. [PMID: 32132640 PMCID: PMC7055225 DOI: 10.1038/s42003-020-0825-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 02/12/2020] [Indexed: 12/24/2022] Open
Abstract
Therapeutic normal IgG intravenous immunoglobulin (IVIG) is a well-established first-line immunotherapy for many autoimmune and inflammatory diseases. Though several mechanisms have been proposed for the anti-inflammatory actions of IVIG, associated signaling pathways are not well studied. As β-catenin, the central component of the canonical Wnt pathway, plays an important role in imparting tolerogenic properties to dendritic cells (DCs) and in reducing inflammation, we explored whether IVIG induces the β-catenin pathway to exert anti-inflammatory effects. We show that IVIG in an IgG-sialylation independent manner activates β-catenin in human DCs along with upregulation of Wnt5a secretion. Mechanistically, β-catenin activation by IVIG requires intact IgG and LRP5/6 co-receptors, but FcγRIIA and Syk are not implicated. Despite induction of β-catenin, this pathway is dispensable for anti-inflammatory actions of IVIG in vitro and for mediating the protection against experimental autoimmune encephalomyelitis in vivo in mice, and reciprocal regulation of effector Th17/Th1 and regulatory T cells.
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Affiliation(s)
- Anupama Karnam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Naresh Rambabu
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Mrinmoy Das
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Melissa Bou-Jaoudeh
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Sandrine Delignat
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Fabian Käsermann
- CSL Behring, Research, CSL Biologics Research Center, 3014, Bern, Switzerland
| | - Sébastien Lacroix-Desmazes
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Srini V Kaveri
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, 15 rue de l'Ecole de Médicine, F-75006, Paris, France.
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12
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Organ-specific mechanisms linking innate and adaptive antifungal immunity. Semin Cell Dev Biol 2018; 89:78-90. [PMID: 29366628 DOI: 10.1016/j.semcdb.2018.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/09/2018] [Accepted: 01/15/2018] [Indexed: 12/24/2022]
Abstract
Fungal infections remain a significant global health problem in humans. Fungi infect millions of people worldwide and cause from acute superficial infections to life-threatening systemic disease to chronic illnesses. Trying to decipher the complex innate and adaptive immune mechanisms that protect humans from pathogenic fungi is therefore a key research goal that may lead to immune-based therapeutic strategies and improved patient outcomes. In this review, we summarize how the cells and molecules of the innate immune system activate the adaptive immune system to elicit long-term immunity to fungi. We present current knowledge and exciting new advances in the context of organ-specific immunity, outlining the tissue-specific tropisms for the major pathogenic fungi of humans, the antifungal functions of tissue-resident myeloid cells, and the adaptive immune responses required to protect specific organs from fungal challenge.
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13
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Neuro-Immune Mechanisms of Anti-Cryptococcal Protection. J Fungi (Basel) 2017; 4:jof4010004. [PMID: 29371497 PMCID: PMC5872307 DOI: 10.3390/jof4010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/10/2017] [Accepted: 12/23/2017] [Indexed: 12/15/2022] Open
Abstract
Cryptococcal meningitis (CM) is a life-threatening fungal disease affecting both immunosuppressed and immunocompetent people. The main causative agent of CM is Cryptococcus neoformans, a basidiomycete fungus prevalent in the environment. Our understanding of the immune mechanisms controlling C. neoformans growth within the central nervous system (CNS) is poor. However, there have been several recent advances in the field of neuroimmunology regarding how cells resident within the CNS, such as microglia and neurons, can participate in immune surveillance and control of infection. In this mini-review, the cells of the CNS are discussed with reference to what is currently known about how they control C. neoformans infection.
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14
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Koutsouras GW, Ramos RL, Martinez LR. Role of microglia in fungal infections of the central nervous system. Virulence 2016; 8:705-718. [PMID: 27858519 DOI: 10.1080/21505594.2016.1261789] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Most fungi are capable of disseminating into the central nervous system (CNS) commonly being observed in immunocompromised hosts. Microglia play a critical role in responding to these infections regulating inflammatory processes proficient at controlling CNS colonization by these eukaryotic microorganisms. Nonetheless, it is this inflammatory state that paradoxically yields cerebral mycotic meningoencephalitis and abscess formation. As peripheral macrophages and fungi have been investigated aiding our understanding of peripheral disease, ascertaining the key interactions between fungi and microglia may uncover greater abilities to treat invasive fungal infections of the brain. Here, we present the current knowledge of microglial physiology. Due to the existing literature, we have described to greater extent the opportunistic mycotic interactions with these surveillance cells of the CNS, highlighting the need for greater efforts to study other cerebral fungal infections such as those caused by geographically restricted dimorphic and rare fungi.
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Affiliation(s)
- George W Koutsouras
- a Department of Biomedical Sciences , NYIT College of Osteopathic Medicine, New York Institute of Technology , Old Westbury , NY , USA
| | - Raddy L Ramos
- a Department of Biomedical Sciences , NYIT College of Osteopathic Medicine, New York Institute of Technology , Old Westbury , NY , USA
| | - Luis R Martinez
- a Department of Biomedical Sciences , NYIT College of Osteopathic Medicine, New York Institute of Technology , Old Westbury , NY , USA
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15
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Yasuda K, Ushio H. Keyhole limpet hemocyanin induces innate immunity via Syk and Erk phosphorylation. EXCLI JOURNAL 2016; 15:474-481. [PMID: 27822175 PMCID: PMC5083961 DOI: 10.17179/excli2016-488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 07/11/2016] [Indexed: 01/01/2023]
Abstract
Hemocyanin is an extracellular respiratory protein containing copper in hemolymph of invertebrates, such as Mollusk and Arthropod. Keyhole limpet hemocyanin (KLH) is one of hemocyanins and has many years of experience for vaccine developments and immunological studies in mammals including human. However, the association between KLH and the immune systems, especially the innate immune systems, remains poorly understood. The aim of this study is to clarify the direct effects of KLH on the innate immune systems. KLH activated an inflammation-related transcription factor NF-κB as much as lipopolysaccharide (LPS) in a human monocytic leukemia THP-1 reporter cell line. We have found that the KLH-induced NF-κB activation is partially involved in a spleen tyrosine kinase (Syk) pathway. We have also successfully revealed that an extracellular signal-regulated kinase (Erk), a member of mitogen-activated protein kinases, is located in an upstream of NF-κB activation induced by KLH. Furthermore, a Syk phosphorylation inhibitor partially suppressed the Erk activation in KLH-stimulated THP-1. These results suggest that both Syk and Erk associate with the KLH-induced NF-κB activation in the human monocyte.
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Affiliation(s)
- Kyoko Yasuda
- Laboratory of Marine Biochemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Hideki Ushio
- Laboratory of Marine Biochemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo
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16
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Abstract
Microglia constitute the powerhouse of the innate immune system in the brain. It is now widely accepted that they are monocytic-derived cells that infiltrate the developing brain at the early embryonic stages, and acquire a resting phenotype characterized by the presence of dense branching processes, called ramifications. Microglia use these dynamic ramifications as sentinels to sense and detect any occurring alteration in brain homeostasis. Once a danger signal is detected, such as molecular factors associated to brain damage or infection, they get activated by acquiring a less ramified phenotype, and mount adequate responses that range from phagocyting cell debris to secreting inflammatory and trophic factors. Here, we review the origin of microglia and we summarize the main molecular signals involved in controlling their function under physiological conditions. In addition, their implication in the pathogenesis of multiple sclerosis and stress is discussed.
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Affiliation(s)
- Ayman ElAli
- Neuroscience Laboratory, CHU de Québec Research Center (CHUL), Department of Psychiatry and Neuroscience, Faculty of Medicine, Laval University Quebec, CA, Canada
| | - Serge Rivest
- Neuroscience Laboratory, CHU de Québec Research Center (CHUL), Department of Molecular Medicine, Faculty of Medicine, Laval University Quebec, CA, Canada
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17
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Manitz MP, Plümper J, Demir S, Ahrens M, Eßlinger M, Wachholz S, Eisenacher M, Juckel G, Friebe A. Flow cytometric characterization of microglia in the offspring of PolyI:C treated mice. Brain Res 2016; 1636:172-182. [PMID: 26872595 DOI: 10.1016/j.brainres.2016.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 11/16/2015] [Accepted: 02/02/2016] [Indexed: 02/07/2023]
Abstract
The neuropathology of schizophrenia has been reported to be closely associated with microglial activation. In a previous study, using the prenatal PolyI:C schizophrenia animal model, we showed an increase in cell numbers and a reduction in microglial branching in 30-day-old PolyI:C descendants, which suggests that there is microglial activation during adolescence. To provide more information about the activation state, we aimed to examine the expression levels of Iba1, which was reported to be up-regulated in activated microglia. We used a flow cytometric approach and investigated CD11b and CD45, two additional markers for the identification of microglial cells. We demonstrated that intracellular staining against Iba1 can be used as a reliable flow cytometric method for identification of microglial cells. Prenatal PolyI:C treatment had long-term effects on CD11b and CD45 expression. It also resulted in a trend towards increased Iba1 expression. Imbalance in CD11b, CD45, and Iba1 expression might contribute to impaired synaptic surveillance and enhanced activation/inflammatory activity of microglia in adult offspring.
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Affiliation(s)
- Marie Pierre Manitz
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Jennifer Plümper
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany
| | - Seray Demir
- Department of Neuroimmunology, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany.
| | - Maike Ahrens
- Medizinisches Proteom-Center, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany.
| | - Manuela Eßlinger
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Simone Wachholz
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Martin Eisenacher
- Medizinisches Proteom-Center, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany.
| | - Georg Juckel
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Astrid Friebe
- Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
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18
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Callaway JB, Smith SA, McKinnon KP, de Silva AM, Crowe JE, Ting JPY. Spleen Tyrosine Kinase (Syk) Mediates IL-1β Induction by Primary Human Monocytes during Antibody-enhanced Dengue Virus Infection. J Biol Chem 2015; 290:17306-20. [PMID: 26032420 DOI: 10.1074/jbc.m115.664136] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Indexed: 11/06/2022] Open
Abstract
Approximately 500,000 people are hospitalized with severe dengue illness annually. Antibody-dependent enhancement (ADE) of dengue virus (DENV) infection is believed to contribute to the pathogenic cytokine storm described in severe dengue patients, but the precise signaling pathways contributing to elevated cytokine production are not elucidated. IL-1β is a potent inflammatory cytokine that is frequently elevated during severe dengue, and the unique dual regulation of IL-1β provides an informative model to study ADE-induced cytokines. This work utilizes patient-derived anti-DENV mAbs and primary human monocytes to study ADE-induced IL-1β and other cytokines. ADE of DENV serotype 2 (DENV-2) elevates mature IL-1β secretion by monocytes independent of DENV replication by 4 h postinoculation (hpi). Prior to this, DENV immune complexes activate spleen tyrosine kinase (Syk) within 1 hpi. Syk induces elevated IL1B, TNF, and IL6 mRNA by 2 hpi. Syk mediates elevated IL-1β secretion by activating ERK1/2, and both Syk and ERK1/2 inhibitors ablated ADE-induced IL-1β secretion. Maturation of pro-IL-1β during ADE requires caspase-1 and NLRP3, but caspase-1 is suboptimally increased by ADE and can be significantly enhanced by a typical inflammasome agonist, ATP. Importantly, this inflammatory Syk-ERK signaling axis requires DENV immune complexes, because DENV-2 in the presence of serotype-matched anti-DENV-2 mAb, but not anti-DENV-1 mAb, activates Syk, ERK, and IL-1β secretion. This study provides evidence that DENV-2 immune complexes activate Syk to mediate elevated expression of inflammatory cytokines. Syk and ERK may serve as new therapeutic targets for interfering with ADE-induced cytokine expression during severe dengue.
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Affiliation(s)
- Justin B Callaway
- From the Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center
| | - Scott A Smith
- the Vanderbilt Vaccine Center and the Departments of Medicine
| | | | | | - James E Crowe
- the Vanderbilt Vaccine Center and Pathology, Microbiology, and Immunology, and Pediatrics, Vanderbilt Medical Center, Nashville, Tennessee 37232
| | - Jenny P-Y Ting
- From the Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, Department of Genetics, and Institute of Inflammatory Diseases, University of North Carolina, Chapel Hill, North Carolina 27599 and
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Abstract
ABSTRACT
Antibodies can impact pathogens in the presence or in the absence of effector cells or effector molecules such as complement, and experiments can often sort out with precision the mechanisms by which an antibody inhibits a pathogen
in vitro
. In addition,
in vivo
models, particularly those engineered to knock in or knock out effector cells or effector molecules, are excellent tools for understanding antibody functions. However, it is highly likely that multiple antibody functions occur simultaneously or sequentially in the presence of an infecting organism
in vivo
. The most critical incentive for measuring antibody functions is to provide a basis for vaccine development and for the development of therapeutic antibodies. In this respect, some functions, such as virus neutralization, serve to inhibit the acquisition of a pathogen or limit its pathogenesis. However, antibodies can also enhance replication or contribute to pathogenesis. This review emphasizes those antibody functions that are potentially beneficial to the host. In addition, this review will focus on the effects of antibodies on organisms themselves, rather than on the toxins the organisms may produce.
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20
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Hu X, Liou AKF, Leak RK, Xu M, An C, Suenaga J, Shi Y, Gao Y, Zheng P, Chen J. Neurobiology of microglial action in CNS injuries: receptor-mediated signaling mechanisms and functional roles. Prog Neurobiol 2014; 119-120:60-84. [PMID: 24923657 PMCID: PMC4121732 DOI: 10.1016/j.pneurobio.2014.06.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/31/2014] [Accepted: 06/03/2014] [Indexed: 12/28/2022]
Abstract
Microglia are the first line of immune defense against central nervous system (CNS) injuries and disorders. These highly plastic cells play dualistic roles in neuronal injury and recovery and are known for their ability to assume diverse phenotypes. A broad range of surface receptors are expressed on microglia and mediate microglial 'On' or 'Off' responses to signals from other host cells as well as invading microorganisms. The integrated actions of these receptors result in tightly regulated biological functions, including cell mobility, phagocytosis, the induction of acquired immunity, and trophic factor/inflammatory mediator release. Over the last few years, significant advances have been made toward deciphering the signaling mechanisms related to these receptors and their specific cellular functions. In this review, we describe the current state of knowledge of the surface receptors involved in microglial activation, with an emphasis on their engagement of distinct functional programs and their roles in CNS injuries. It will become evident from this review that microglial homeostasis is carefully maintained by multiple counterbalanced strategies, including, but not limited to, 'On' and 'Off' receptor signaling. Specific regulation of theses microglial receptors may be a promising therapeutic strategy against CNS injuries.
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Affiliation(s)
- Xiaoming Hu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China; Geriatric Research, Educational and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15240, USA.
| | - Anthony K F Liou
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Mingyue Xu
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Chengrui An
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Jun Suenaga
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yejie Shi
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Ping Zheng
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Jun Chen
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China; Geriatric Research, Educational and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15240, USA.
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21
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Yi H, Bai Y, Zhu X, lin L, Zhao L, Wu X, Buch S, Wang L, Chao J, Yao H. IL-17A Induces MIP-1α Expression in Primary Astrocytes via Src/MAPK/PI3K/NF-kB Pathways: Implications for Multiple Sclerosis. J Neuroimmune Pharmacol 2014; 9:629-41. [DOI: 10.1007/s11481-014-9553-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 06/26/2014] [Indexed: 02/01/2023]
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22
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IL-32γ induces chemotaxis of activated T cells via dendritic cell-derived CCL5. Biochem Biophys Res Commun 2014; 450:30-5. [PMID: 24882804 DOI: 10.1016/j.bbrc.2014.05.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 05/14/2014] [Indexed: 11/21/2022]
Abstract
Interleukin (IL)-32 has been associated with a variety of inflammatory diseases including rheumatoid arthritis, vasculitis and Crohn's disease. We have previously reported that IL-32γ, the IL-32 isoform with the highest biological activity, could act as an immune modulator through regulation of dendritic cell (DC) functions in immune responses. Cell locomotion is crucial for induction of an effective immune response. In this study, we investigated the effect and underlying mechanisms of IL-32γ on recruitment of T cells. IL-32γ upregulated the expression of several chemokines including CCL2, CCL4, and CCL5 in the DCs. In particular, IL-32γ significantly increased CCL5 expression in a dose-dependent manner. Treatment with JNK and NF-κB inhibitors suppressed IL-32γ-induced CCL5 expression in DCs, indicating that IL-32γ induced CCL5 production through the JNK and NF-κB pathways. Furthermore, supernatants from IL-32γ-treated DCs showed chemotactic activities controlling migration of activated CD4(+) and CD8(+) T cells, and these activities were suppressed by addition of neutralizing anti-CCL5 antibody. These results show that IL-32γ effectively promotes migration of activated T cells via CCL5 production in DCs. The chemotactic potential of IL-32γ may explain the pro-inflammatory effects of IL-32 and the pathologic role of IL-32 in immune disorders such as rheumatoid arthritis.
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23
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Doens D, Fernández PL. Microglia receptors and their implications in the response to amyloid β for Alzheimer's disease pathogenesis. J Neuroinflammation 2014; 11:48. [PMID: 24625061 PMCID: PMC3975152 DOI: 10.1186/1742-2094-11-48] [Citation(s) in RCA: 237] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 02/24/2014] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is a major public health problem with substantial economic and social impacts around the world. The hallmarks of AD pathogenesis include deposition of amyloid β (Aβ), neurofibrillary tangles, and neuroinflammation. For many years, research has been focused on Aβ accumulation in senile plaques, as these aggregations were perceived as the main cause of the neurodegeneration found in AD. However, increasing evidence suggests that inflammation also plays a critical role in the pathogenesis of AD. Microglia cells are the resident macrophages of the brain and act as the first line of defense in the central nervous system. In AD, microglia play a dual role in disease progression, being essential for clearing Aβ deposits and releasing cytotoxic mediators. Aβ activates microglia through a variety of innate immune receptors expressed on these cells. The mechanisms through which amyloid deposits provoke an inflammatory response are not fully understood, but it is believed that these receptors cooperate in the recognition, internalization, and clearance of Aβ and in cell activation. In this review, we discuss the role of several receptors expressed on microglia in Aβ recognition, uptake, and signaling, and their implications for AD pathogenesis.
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Affiliation(s)
- Deborah Doens
- Centro de Biología Molecular y Celular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT-AIP), Edificio 219, Clayton, Ciudad del Saber, República de Panamá
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, India
| | - Patricia L Fernández
- Centro de Biología Molecular y Celular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT-AIP), Edificio 219, Clayton, Ciudad del Saber, República de Panamá
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24
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Zeng KW, Wang S, Dong X, Jiang Y, Jin HW, Tu PF. Sesquiterpene dimmer (DSF-27) inhibits the release of neuroinflammatory mediators from microglia by targeting spleen tyrosine kinase (Syk) and Janus kinase 2 (Jak2): Two major non-receptor tyrosine signaling proteins involved in inflammatory events. Toxicol Appl Pharmacol 2014; 275:244-56. [DOI: 10.1016/j.taap.2014.01.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 01/17/2014] [Accepted: 01/21/2014] [Indexed: 11/26/2022]
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25
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Wang L, Jiang Q, Chu J, Lin L, Li XG, Chai GS, Wang Q, Wang JZ, Tian Q. Expression of Tau40 induces activation of cultured rat microglial cells. PLoS One 2013; 8:e76057. [PMID: 24146816 PMCID: PMC3795725 DOI: 10.1371/journal.pone.0076057] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 08/20/2013] [Indexed: 12/13/2022] Open
Abstract
Accumulation of microtubule-associated protein tau has been observed in the brain of aging and tauopathies. Tau was observed in microglia, but its role is not illustrated. By immunofluorescence staining and the fractal dimension value assay in the present study, we observed that microglia were activated in the brains of rats and mice during aging, simultaneously, the immunoreactivities of total tau and the phosphorylated tau were significantly enhanced in the activated microglia. Furtherly by transient transfection of tau40 (human 2N/4R tau) into the cultured rat microglia, we demonstrated that expression of tau40 increased the level of Iba1, indicating activation of microglia. Moreover, expression of tau40 significantly enhanced the membranous localization of the phosphorylated tau at Ser396 in microglia possibly by a mechanism involving protein phosphatase 2A, extracellular signal-regulated kinase and glycogen synthase kinase-3β. It was also found that expression of tau40 promoted microglial migration and phagocytosis, but not proliferation. And we observed increased secretion of several cytokines, including interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor-α and nitric oxide after the expression of tau40. These data suggest a novel role of human 2N/4R tau in microglial activation.
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Affiliation(s)
- Lu Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, China
| | - Qian Jiang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiang Chu
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Li Lin
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Guang Li
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gao-Shang Chai
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qun Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (JZW); (QT)
| | - Qing Tian
- Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (JZW); (QT)
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26
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Insight on signal transduction pathways involved in phagocytosis in the colonial ascidian Botryllus schlosseri. J Invertebr Pathol 2013; 112:260-6. [DOI: 10.1016/j.jip.2012.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/05/2012] [Accepted: 12/08/2012] [Indexed: 11/20/2022]
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27
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Immunoglobulin-Mediated Neuro-Cognitive Impairment: New Data and a Comprehensive Review. Clin Rev Allergy Immunol 2013; 45:248-55. [DOI: 10.1007/s12016-013-8357-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Okamura T, Katayama T, Obinata C, Iso Y, Chiba Y, Kobayashi H, Yamada Y, Harashima H, Minami M. Neuronal injury induces microglial production of macrophage inflammatory protein-1α in rat corticostriatal slice cultures. J Neurosci Res 2012; 90:2127-33. [PMID: 22791363 DOI: 10.1002/jnr.23105] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/26/2012] [Accepted: 05/28/2012] [Indexed: 12/21/2022]
Abstract
Chemokines are potent chemoattractants for immune and hematopoietic cells. In the central nervous system, chemokines play an important role in inflammatory responses through activation of infiltrating leukocytes and/or resident glial cells. We previously demonstrated that N-methyl-D-aspartate (NMDA)-evoked neuronal injury induced astrocytic production of monocyte chemoattractant protein-1 (MCP-1, CCL2) via sustained activation of extracellular signal-regulated kinase (ERK) in rat organotypic slice cultures. In the present study, we examined mRNA expression and protein production of macrophage inflammatory protein-1α (MIP-1α, CCL3) induced by NMDA-evoked neuronal injury in the slice cultures. MIP-1α mRNA expression was transiently increased by NMDA treatment in a concentration-dependent manner. Double-fluorescence immunohistochemistry revealed that MIP-1α was produced predominantly in microglia. Depletion of microglial cells from the slice cultures by pretreatment with liposome-encapsulated clodronate abrogated the increase in MIP-1α mRNA expression after NMDA treatment. NMDA-induced MIP-1α mRNA expression was partially but significantly inhibited by the c-Jun N-terminal kinase inhibitor SP600125; conversely, the p38 mitogen-activated protein (MAP) kinase inhibitor SB203580 enhanced it. U0126, a MAP kinase/ERK kinase inhibitor, did not affect mRNA expression. These results, combined with our previous findings, demonstrate that NMDA-evoked neuronal injury differentially induces MIP-1α and MCP-1 production in microglia and astrocytes, respectively, through activation of different intracellular signaling pathways.
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Affiliation(s)
- Toshiyuki Okamura
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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29
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Parajuli B, Sonobe Y, Kawanokuchi J, Doi Y, Noda M, Takeuchi H, Mizuno T, Suzumura A. Immunoglobulin G(1) immune complex upregulates interferon-γ-induced nitric oxide production via ERK1/2 activation in murine microglia. J Neuroimmunol 2012; 244:57-62. [PMID: 22306300 DOI: 10.1016/j.jneuroim.2012.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/28/2011] [Accepted: 01/09/2012] [Indexed: 01/05/2023]
Abstract
Intrathecal Immunoglobulin G (IgG) is elevated in some central nervous system (CNS) diseases and microglia upregulate Fcγ receptors in various neurological disorders. However, the interaction between IgG or IgG immune complexes and microglial Fcγ receptors is not fully understood. In this study, the effect of IgG(1) immune complexes on microglia was investigated. IgG(1) immune complexes increased nitric oxide production in murine microglia in the presence of interferon (IFN)-γ. These effects were dependent upon IgG(1) immune complex-induced activation of spleen tyrosine kinase with subsequent activation of extracellular signal regulated kinase1/2. Collectively, these results indicate that IgG(1) immune complexes can exert immunomodulatory effects in various central nervous system disorders.
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Affiliation(s)
- Bijay Parajuli
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
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Yan C, Zhu M, Staiger J, Johnson PF, Gao H. C5a-regulated CCAAT/enhancer-binding proteins β and δ are essential in Fcγ receptor-mediated inflammatory cytokine and chemokine production in macrophages. J Biol Chem 2011; 287:3217-30. [PMID: 22147692 DOI: 10.1074/jbc.m111.280834] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
CCAAT/enhancer-binding protein β (C/EBPβ) and C/EBPδ are known to participate in the regulation of many genes associated with inflammation. However, little is known about the activation and function of C/EBPβ and -δ in inflammatory responses elicited by Fcγ receptor (FcγR) activation. Here we show that C/EBPβ and -δ activation are induced in IgG immune complex (IC)-treated macrophages. The increased expression of C/EBPβ and -δ occurred at both mRNA and protein levels. Furthermore, induction of C/EBPβ and -δ was mediated, to a large extent, by activating FcγRs. Using siRNA-mediated knockdown as well as macrophages deficient for C/EBPβ and/or -δ, we demonstrate that C/EBPβ and -δ play a critical role in the production of TNF-α, MIP-2, and MIP-1α in IgG IC-stimulated macrophages. Moreover, both ERK1/2 and p38 MAPK are involved in C/EBP induction and TNF-α, MIP-2, and MIP-1α production induced by IgG IC. We provide the evidence that C5a regulates IgG IC-induced inflammatory responses by enhancing ERK1/2 and p38 MAPK activities as well as C/EBPβ and -δ activities. Collectively, these data suggest that C/EBPβ and -δ are key regulators for FcγR-mediated induction of cytokines and chemokines in macrophages. Furthermore, C/EBPs may play an important regulatory role in IC-associated inflammatory responses.
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Affiliation(s)
- Chunguang Yan
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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31
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Olsnes C, Olofsson J, Aarstad HJ. MAPKs ERK and p38, but not JNK Phosphorylation, Modulate IL-6 and TNF-α Secretion Following OK-432 In Vitro Stimulation of Purified Human Monocytes. Scand J Immunol 2011; 74:114-25. [DOI: 10.1111/j.1365-3083.2011.02555.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Luo Y, Pollard JW, Casadevall A. Fcgamma receptor cross-linking stimulates cell proliferation of macrophages via the ERK pathway. J Biol Chem 2009; 285:4232-4242. [PMID: 19996316 DOI: 10.1074/jbc.m109.037168] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Macrophage proliferation can be stimulated by phagocytosis and by cross-linking of Fcgamma receptors (FcgammaR). In this study, we investigated the role of FcgammaR and the signaling cascades that link FcgammaR activation to cell cycle progression. This effect was mediated by the activating FcgammaR, including FcgammaRI and III, via their Fcgamma subunit. Further investigation revealed that the cell cycle machinery was activated by FcgammaR cross-linking through downstream signaling events. Specifically, we identified the extracellular signal-regulated kinase (ERK) signaling pathway as a mediator of signals from FcgammaR activation to cyclin D1 expression, because cyclin D1 expression associated with FcgammaR cross-linking was attenuated by specific inhibitors of the ERK1/2 signaling pathway, PD98059 and U0126 and the spleen tyrosine kinase (Syk) inhibitor, Piceatannol. Our findings establish a link between the ERK activation and cell cycle signaling pathways, thus providing a causal mechanism by which FcgammaR activation produces a mitogenic effect that stimulates macrophage proliferation. Macrophage mitosis following FcgammaR activation could potentially affect the outcome of macrophage interactions with intracellular pathogens. In addition, our results suggest the possibility of new treatment options for certain infectious diseases, chronic inflammatory diseases, and leukemias based on interference with FcgammaR-stimulated macrophage cell proliferation.
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Affiliation(s)
- Yong Luo
- From the Departments of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Jeffrey W Pollard
- Departments of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461; Departments of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Arturo Casadevall
- From the Departments of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461; Departments of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
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Okun E, Mattson MP, Arumugam TV. Involvement of Fc receptors in disorders of the central nervous system. Neuromolecular Med 2009; 12:164-78. [PMID: 19844812 DOI: 10.1007/s12017-009-8099-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/07/2009] [Indexed: 01/09/2023]
Abstract
Immunoglobulins are proteins with a highly variable antigen-binding domain and a constant region (Fc domain) that binds to a cell surface receptor (FcR). Activation of FcRs in immune cells (lymphocytes, macrophages, and mast cells) triggers effector responses including cytokine production, phagocytosis, and degranulation. In addition to their roles in normal responses to infection or tissue injury, and in immune-related diseases, FcRs are increasingly recognized for their involvement in neurological disorders. One or more FcRs are expressed in microglia, astrocytes, oligodendrocytes, and neurons. Aberrant activation of FcRs in such neural cells may contribute to the pathogenesis of major neurodegenerative conditions including Alzheimer's disease, Parkinson's disease, ischemic stroke, and multiple sclerosis. On the other hand, FcRs may play beneficial roles in counteracting pathological processes; for e.g., FcRs may facilitate removal of amyloid peptides from the brain and so protect against Alzheimer's disease. Knowledge of the functions of FcRs in the nervous system in health and disease is leading to novel preventative and therapeutic strategies for stroke, Alzheimer's disease, and other neurological disorders.
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Affiliation(s)
- Eitan Okun
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
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Kawashita E, Tsuji D, Kawashima N, Nakayama KI, Matsuno H, Itoh K. Abnormal production of macrophage inflammatory protein-1alpha by microglial cell lines derived from neonatal brains of Sandhoff disease model mice. J Neurochem 2009; 109:1215-24. [PMID: 19302485 DOI: 10.1111/j.1471-4159.2009.06041.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sandhoff disease (SD) is a lysosomal beta-hexosaminidase deficiency involving excessive accumulation of undegraded substrates, including terminal N-acetylglucosamine-oligosaccharides and GM2 ganglioside, and progressive neurodegeneration. Our previous study demonstrated remarkable induction of macrophage inflammatory factor-1alpha (MIP-1alpha) in microglia in the brains of SD model mice as a putative pathogenic factor for SD via microglia-mediated neuroinflammation. In this study, we established microglial cell lines (WT- and SD-Mg) from wild-type and SD mice, and first demonstrated the enhanced production of MIP-1alpha in SD-Mg. Inhibitors of protein kinase C (PKC) and Akt reduced the production of MIP-1alpha by SD-Mg. Elevated activation of Akt and partial translocation of PKC isozymes (alpha, betaI, betaII, and delta) from the cytoplasm to the membrane in SD-Mg were also revealed by means of immunoblotting. Furthermore, it was demonstrated that intracellular extracellular signal-regulated kinase, c-Jun N-terminal kinase, and phospholipase C (PLC), but not phosphoinositide 3-kinase, should contribute to the induction of MIP-1alpha in SD-Mg, and that PLC could independently regulate the activation of both PKC and Akt. We proposed here that the deregulated activation of PLC should cause the enhanced MIP-1alpha production via plural signaling pathways mediated by PKC and Akt, followed by extracellular signal-regulated kinase and c-Jun N-terminal kinase, in SD-Mg.
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Affiliation(s)
- Eri Kawashita
- Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, Tokushima, Tokushima, Japan
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Enhanced innate immune responsiveness to pulmonary Cryptococcus neoformans infection is associated with resistance to progressive infection. Infect Immun 2008; 76:4745-56. [PMID: 18678664 DOI: 10.1128/iai.00341-08] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Genetically regulated mechanisms of host defense against Cryptococcus neoformans infection are not well understood. In this study, pulmonary infection with the moderately virulent C. neoformans strain 24067 was used to compare the host resistance phenotype of C57BL/6J with that of inbred mouse strain SJL/J. At 7 days or later after infection, C57BL/6J mice exhibited a significantly greater fungal burden in the lungs than SJL/J mice. Characterization of the pulmonary innate immune response at 3 h after cryptococcal infection revealed that resistant SJL/J mice exhibited significantly higher neutrophilia, with elevated levels of inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) and keratinocyte-derived chemokine (KC)/CXCL1 in the airways, as well as increased whole-lung mRNA expression of chemokines KC/CXCL1, MIP-1alpha/CCL3, MIP-1beta/CCL4, MIP-2/CXCL2, and MCP-1/CCL2 and cytokines interleukin 1beta (IL-1beta) and IL-1Ra. At 7 and 14 days after infection, SJL/J mice maintained significantly higher levels of TNF-alpha and KC/CXCL1 in the airways and exhibited a Th1 response characterized by elevated levels of lung gamma interferon (IFN-gamma) and IL-12/IL-23p40, while C57BL/6J mice exhibited Th2 immunity as defined by eosinophilia and IL-4 production. Alveolar and resident peritoneal macrophages from SJL/J mice also secreted significantly greater amounts of TNF-alpha and KC/CXCL1 following in vitro stimulation with C. neoformans. Intracellular signaling analysis demonstrated that TNF-alpha and KC/CXCL1 production was regulated by NF-kappaB and phosphatidylinositol 3 kinase in both strains; however, SJL/J macrophages exhibited heightened and prolonged activation in response to C. neoformans infection compared to that of C57BL/6J. Taken together, these data demonstrate that an enhanced innate immune response against pulmonary C. neoformans infection in SJL/J mice is associated with natural resistance to progressive infection.
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Widespread Unilateral Pain Associated With Herpes Simplex Virus Infections. THE JOURNAL OF PAIN 2008; 9:658-65. [DOI: 10.1016/j.jpain.2008.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/01/2008] [Accepted: 02/02/2008] [Indexed: 11/21/2022]
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37
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Tsuda M, Ueno H, Kataoka A, Tozaki-Saitoh H, Inoue K. Activation of dorsal horn microglia contributes to diabetes-induced tactile allodynia via extracellular signal-regulated protein kinase signaling. Glia 2008; 56:378-86. [PMID: 18186080 DOI: 10.1002/glia.20623] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Painful neuropathy is one of the most common complications of diabetes, one hallmark of which is tactile allodynia (pain hypersensitivity to innocuous stimulation). The underlying mechanisms of tactile allodynia are, however, poorly understood. Emerging evidence indicates that, following nerve injury, activated microglia in the spinal cord play a crucial role in tactile allodynia. However, it remains unknown whether spinal microglia are activated under diabetic conditions and whether they contribute to diabetes-induced tactile allodynia. In the present study, using streptozotocin (STZ)-induced diabetic rats that displayed tactile allodynia, we found several morphological changes of activated microglia in the dorsal horn. These included increases in Iba1 and OX-42 labeling (markers of microglia), hypertrophic morphology, the thickness and the retraction of processes, and in the number of activated microglia cells. Furthermore, in the dorsal horn of STZ diabetic rats, extracellular signal-regulated protein kinase (ERK) and an upstream kinase, Src-family kinase (SFK), both of which are implicated in microglial functions, were activated exclusively in microglia. Moreover, inhibition of ERK phosphorylation in the dorsal horn by intrathecal administration of U0126, an inhibitor of ERK activation, produced a striking alleviation of existing, long-term tactile allodynia of diabetic rats. We also found that a single administration of U0126 reduced the expression of allodynia. Together, these results suggest that activated dorsal horn microglia may be a crucial component of diabetes-induced tactile allodynia, mediated, in part, by the ERK signaling pathway. Thus, inhibiting microglia activation in the dorsal horn may represent a therapeutic strategy for treating diabetic tactile allodynia.
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Affiliation(s)
- Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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38
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Shiratsuchi H, Basson MD. Akt2, but not Akt1 or Akt3 mediates pressure-stimulated serum-opsonized latex bead phagocytosis through activating mTOR and p70 S6 kinase. J Cell Biochem 2008; 102:353-67. [PMID: 17372934 DOI: 10.1002/jcb.21295] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Monocytes and macrophages play critical roles in innate host defense and are sensitive to mechanical stimuli. Tissue pressure is often altered in association with inflammation or infection. Low pressure (20 mmHg), equivalent to normal tissue pressure, increases phagocytosis by primary monocytes and PMA-differentiated THP-1 macrophages, in part by FAK and ERK inhibition and p38 activation. PI-3K is required for macrophage phagocytosis, but whether PI-3K mediates pressure-stimulated phagocytosis is not known. Furthermore, little is known about the role played by the PI-3K downstream Kinases, Akt, and p70 S6 kinase (p70S6K) in modulating macrophage phagocytosis. Thus, we studied the contribution of PI-3K, Akt, and p70S6K to pressure-increased serum-opsonized bead phagocytosis. Pressure-induced p85 PI-3K translocation from cytosolic to membrane fractions and increased Akt activation by 36.1 +/- 12.0% in THP-1 macrophages. LY294002 or Akt inhibitor IV abrogated pressure-stimulated but not basal phagocytosis. Basal Akt activation was inhibited 90% by LY294002 and 70% by Akt inhibitor IV. Each inhibitor prevented Akt activation by pressure. SiRNA targeted to Akt1, Akt2, or Akt3 reduced Akt1, Akt2, and Akt3 expression by 50%, 45%, and 40%, respectively. However, only Akt2SiRNA abrogated the pressure-stimulated phagocytosis without affecting basal. Pressure also activated mTOR and p70S6K. mTORSiRNA and p70S6K inhibition by rapamycin or p70S6KSiRNA blocked pressure-induced, but not basal, phagocytosis. Changes in tissue pressure during inflammation may regulate macrophage phagocytosis by activation of PI-3K, which activates Akt2, mTOR, and p70S6K.
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Affiliation(s)
- Hiroe Shiratsuchi
- Department of Surgery, Wayne State University, School of Medicine, and John D. Dingell VA Medical Center, Detroit, Michigan 48201, USA.
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39
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Parsa KVL, Butchar JP, Rajaram MVS, Cremer TJ, Tridandapani S. The tyrosine kinase Syk promotes phagocytosis of Francisella through the activation of Erk. Mol Immunol 2008; 45:3012-21. [PMID: 18295889 DOI: 10.1016/j.molimm.2008.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 01/15/2008] [Indexed: 11/29/2022]
Abstract
Francisella tularensis is a highly infectious, Gram-negative intra-cellular pathogen that can cause the zoonotic disease tularemia. Although the receptors critical for internalization of Francisella by macrophages are beginning to be defined, the identity of the downstream signaling pathways essential for the engulfment are not yet identified. In this study we have tested the role of Syk in the phagocytosis of Francisella. We report that Syk is activated during Francisella infection and is critical for the uptake of the organisms. Pharmacologic inhibition of Syk almost completely abrogated uptake, whereas the overexpression of Syk significantly enhanced uptake. However, Syk appears to be dispensable during initial host-pathogen contact. Further analyses of the molecular mechanism of Syk influence on Francisella uptake revealed that the MAPK Erk but not the phosphatidylinositol 3 kinase (PI3K)/Akt pathway is the downstream effector of Syk. Thus, the inhibition of Erk in Syk-overexpressing cells or the inhibition of Syk in Erk-overexpressing cells led to a significant attenuation of uptake. Collectively, these data identify Syk and Erk as key players in the phagocytosis of Francisella.
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Affiliation(s)
- Kishore V L Parsa
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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40
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Rice T, Larsen J, Rivest S, Yong VW. Characterization of the early neuroinflammation after spinal cord injury in mice. J Neuropathol Exp Neurol 2007; 66:184-95. [PMID: 17356380 DOI: 10.1097/01.jnen.0000248552.07338.7f] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The occurrence of neuroinflammation after spinal cord injury (SCI) is well established, but its function is debated, with both beneficial and detrimental consequences ascribed. A discriminate of the role of neuroinflammation may be the time period after SCI, and there is evidence to favor early neuroinflammation being undesirable, whereas the later evolving phase may have useful roles. Here, we have focused on the inflammatory response in the first 24 hours of SCI in mice. We found elevation of interleukin (IL)-1beta and other cytokines and chemokines within 15 minutes to 3 hours of injury. The early neuroinflammation in SCI is likely to be CNS-derived and involves microglia, as demonstrated by in situ hybridization for IL-1beta in microglia, by an in vitro model of SCI in which elevation of inflammatory cytokines occurs in the absence of a dynamic source of infiltrating leukocytes, and by the correlation of decreased levels of inflammatory molecules and microglia activity in IL-1beta-null mice. Nonetheless, as there are no specific immunohistochemical markers that clearly differentiate microglia from their peripheral counterparts, macrophages, the latter cannot be definitively excluded as participants in early neuroinflammation in mouse SCI. These results of an instantaneous inflammatory response validate approaches to modulate microglia/macrophage activity to improve recovery from SCI.
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Affiliation(s)
- Tiffany Rice
- Hotchkiss Brain Institute and Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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41
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Yang Z, Mosser DM, Zhang X. Activation of the MAPK, ERK, following Leishmania amazonensis infection of macrophages. THE JOURNAL OF IMMUNOLOGY 2007; 178:1077-85. [PMID: 17202371 PMCID: PMC2643020 DOI: 10.4049/jimmunol.178.2.1077] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IL-10 is a critical cytokine in determining host susceptibility to Leishmania spp. We previously demonstrated that macrophage-derived IL-10 could contribute to disease exacerbation, but the mechanisms whereby Leishmania infections led to IL-10 induction were not fully understood. In this study, we demonstrated that infection of macrophages with Leishmania amazonensis amastigotes led to the activation of the MAPK, ERK1/2. This activation was required, but not sufficient for IL-10 induction. In addition to ERK activation, an inflammatory stimulus, such as low m.w. hyaluronic acid from the extracellular matrix, must also be present. The combination of these two signals resulted in the superinduction of IL-10. We also demonstrated that IgG on the surface of Leishmania amastigotes was required to achieve maximal IL-10 production from infected macrophages. Surface IgG engages macrophage FcgammaR to induce ERK activation. Macrophages lacking FcgammaR, or macrophages treated with an inhibitor of spleen tyrosine kinase, the tyrosine kinase that signals via FcgammaR, failed to activate ERK and consequently failed to produce IL-10 following infection with Leishmania amastigotes. We confirmed that ERK1/2 activation led to the phosphorylation of histone H3 at the IL-10 promoter, and this phosphorylation allowed for the binding of the transcription factor, Sp1, to the IL-10 promoter. Finally, the administration of U0126, an inhibitor of ERK activation, to infected mice resulted in decreased lesion progression with reduced numbers of parasites in them. Thus, our findings reveal an important role of MAPK, ERK signaling in the pathogenesis of Leishmania infection.
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Affiliation(s)
| | - David M. Mosser
- Address correspondence and reprint requests to Dr. David M. Mosser, 1103 Microbiology Building, University of Maryland, College Park, MD 20742. E-mail address:
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Nishimura M, Takanashi M, Okazaki H, Satake M, Nakajima K. Role of CD7 expressed in lung microvascular endothelial cells as Fc receptor for immunoglobulin M. ACTA ACUST UNITED AC 2007; 13:287-92. [PMID: 16990185 DOI: 10.1080/10623320600904138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Immunoglobulins (Igs) against anti-human white blood cells are putative contributors to the development of transfusion-related adverse effects, particularly transfusion-related acute lung injury (TRALI). Studies of Igs that are considered to be implicated in transfusion-related adverse effects have mainly focused on immunoglobulin G (IgG) class antibodies (Abs). In the authors' previous in vitro study, the association of polymorphonuclear neutrophils (PMNs) and lung microvascular endothelial (LME) cells was up-regulated in the presence of normal human serum-derived IgMs, when F(ab')2 fragments of IgMs were specific to low-affinity Fc receptors (FcR) for IgG, namely, Fcgamma R III (CD16) and Fcgamma RII (CD32). In this study, the authors found that CD7 antigen notably expresses in LME cells and that it acts as an Fc receptor for IgM in LME cells.
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Affiliation(s)
- Motoko Nishimura
- Research Section, Tokyo Metropolitan Red Cross Blood Center, Tokyo, Japan.
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Logan MA, Freeman MR. The scoop on the fly brain: glial engulfment functions in Drosophila. NEURON GLIA BIOLOGY 2007; 3:63-74. [PMID: 18172512 PMCID: PMC2171361 DOI: 10.1017/s1740925x07000646] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Glial cells provide support and protection for neurons in the embryonic and adult brain, mediated in part through the phagocytic activity of glia. Glial cells engulf apoptotic cells and pruned neurites from the developing nervous system, and also clear degenerating neuronal debris from the adult brain after neural trauma. Studies indicate that Drosophila melanogaster is an ideal model system to elucidate the mechanisms of engulfment by glia. The recent studies reviewed here show that many features of glial engulfment are conserved across species and argue that work in Drosophila will provide valuable cellular and molecular insight into glial engulfment activity in mammals.
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Affiliation(s)
- Mary A Logan
- University of Massachusetts Medical School, Department of Neurobiology 770P, 364 Plantation Street, Worcester, MA 01605, USA.
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Kim MO, Suh HS, Si Q, Terman BI, Lee SC. Anti-CD45RO suppresses human immunodeficiency virus type 1 replication in microglia: role of Hck tyrosine kinase and implications for AIDS dementia. J Virol 2007; 80:62-72. [PMID: 16352531 PMCID: PMC1317521 DOI: 10.1128/jvi.80.1.62-72.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages and microglia are productively infected by HIV-1 and play a pivotal role in the pathogenesis of AIDS dementia. Although macrophages and microglia express CD45, a transmembrane protein tyrosine phosphatase, whether modulation of its activity affects human immunodeficiency virus type 1 (HIV-1) replication is unknown. Here, we report that of the five human CD45 isoforms, microglia express CD45RB and CD45RO (RB > RO) and treatment of microglia with a CD45 agonist antibody alphaCD45RO (UCHL-1) inhibits HIV-1 replication. alphaCD45RO prevented HIV-1 negative factor (Nef)-induced autophosphorylation of hematopoietic cell kinase (Hck), a myeloid lineage-specific Src kinase. Recombinant CD45 protein also inhibited HIV-1-induced Hck phosphorylation in microglia. Antennapedia-mediated delivery of Hck Src homology domain 3 (SH3), a domain that binds to the Nef PxxP motif with high affinity, reduced HIV-1-induced Hck phosphorylation and HIV-1 production in microglia. HIV-1-induced LTR transactivation was observed in U38 cells stably overexpressing wild-type Hck but not kinase-inactive Hck. In microglia, alphaCD45RO reduced activation of transcription factors (NF-kappaB and CCAAT enhancer binding protein) necessary for LTR transactivation in macrophages. These results establish that in myeloid lineage cells, Nef interacts with the Hck SH3 domain, resulting in autophosphorylation of Hck and an increase in HIV-1 transcription. alphaCD45RO-mediated inhibition of HIV-1 replication in microglia identifies the CD45 protein tyrosine phosphatase as a potential therapeutic target for HIV-1 infection/AIDS dementia.
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Affiliation(s)
- Mee-Ohk Kim
- Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
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45
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Shideman CR, Hu S, Peterson PK, Thayer SA. CCL5 evokes calcium signals in microglia through a kinase-, phosphoinositide-, and nucleotide-dependent mechanism. J Neurosci Res 2006; 83:1471-84. [PMID: 16547971 DOI: 10.1002/jnr.20839] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microglia, the resident macrophages of the CNS, are responsible for the innate immune response in the brain and participate in the pathogenesis of certain neurodegenerative disorders. Chemokines initiate activation and migration of microglia. The beta-chemokine CCL5 induces an elevation in intracellular calcium concentration ([Ca(2+)](i)) in human microglia. Here, we examined the signal transduction pathway linking activation of chemokine receptor CCR5 to an elevation in [Ca(2+)](i) in cultured microglia by using pharmacological approaches in combination with Fura-2-based digital imaging. The CCL5-induced response required Janus kinase (Jak) activity and the stimulation of an inhibitory G protein. Multiple downstream signaling pathways were involved, including phosphatidylinositol 3-kinase (PI3K), Bruton's tyrosine kinase (Btk), and phospholipase C (PLC)-mediated release of Ca(2+) from inositol 1,4,5-trisphosphate (IP(3))-sensitive stores. Activation of both the kinase and the lipase pathways was required for eliciting the Ca(2+) response. However, the majority of the [Ca(2+)](i) increase was derived from sources activated by NAD metabolites. Cyclic ADP-ribose (cADPR) evoked Ca(2+) release from intracellular stores, and ADPR evoked Ca(2+) influx via a nimodipine-sensitive channel. Thus, a multistep cascade couples CCR5 activation to Ca(2+) increases in human microglia. Because changes in [Ca(2+)](i) affect chemotaxis, secretion, and gene expression, pharmacologic modulation of this pathway may alter inflammatory and degenerative processes in the CNS.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/immunology
- Cells, Cultured
- Chemokine CCL5
- Chemokines, CC/immunology
- Chemokines, CC/metabolism
- Chemokines, CC/pharmacology
- Cyclic ADP-Ribose/metabolism
- Encephalitis/immunology
- Encephalitis/metabolism
- Encephalitis/physiopathology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Immunity, Innate/immunology
- Immunologic Surveillance/immunology
- Inositol 1,4,5-Trisphosphate/metabolism
- Janus Kinase 1
- Microglia/drug effects
- Microglia/immunology
- Microglia/metabolism
- NAD/metabolism
- Nerve Degeneration/immunology
- Nerve Degeneration/metabolism
- Nerve Degeneration/physiopathology
- Phosphatidylinositol 3-Kinases/metabolism
- Protein-Tyrosine Kinases/metabolism
- Receptors, CCR5/agonists
- Receptors, CCR5/immunology
- Receptors, CCR5/metabolism
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Signal Transduction/physiology
- Type C Phospholipases/metabolism
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Affiliation(s)
- C R Shideman
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
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46
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Yang CS, Lee JS, Song CH, Hur GM, Lee SJ, Tanaka S, Akira S, Paik TH, Jo EK. Protein kinase C zeta plays an essential role for Mycobacterium tuberculosis-induced extracellular signal-regulated kinase 1/2 activation in monocytes/macrophages via Toll-like receptor 2. Cell Microbiol 2006; 9:382-96. [PMID: 16925784 DOI: 10.1111/j.1462-5822.2006.00797.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study characterized the upstream signalling molecules involved in extracellular signal-regulated kinase (ERK) 1/2 activation and determined their effects on differential tumour necrosis factor (TNF)-alpha expression by monocytes/macrophages infected with virulent or avirulent mycobacteria. The avirulent Mycobacterium tuberculosis (MTB) strain H37Ra (MTBRa) induced higher levels of activation of ERK 1/2 and the upstream MAPK kinase (MEK)1 and, subsequently, higher levels of TNF-alpha expression in human primary monocytes and monocyte-derived macrophages, as compared with MTB strain H37Rv (MTBRv). The MTB-induced activation of ERK 1/2 was not dependent on Ras or Raf. However, inhibition of the activity of atypical protein kinase C (PKC) zeta decreased the in vitro phosphorylation of MEK, ERK 1/2 activation and subsequent TNF-alpha induction caused by MTBRv or MTBRa. Toll-like receptor (TLR) 2 was found to play a major role in MTB-induced TNF-alpha expression and PKCzeta phosphorylation. Co-immunoprecipitation experiments showed that PKCzeta interacts physically with TLR2 after MTB stimulation. Moreover, PKCzeta phosphorylation was increased more in macrophages following MTBRa, versus MTBRv, infection. This is the first demonstration that PKCzeta interacts with TLR2 to play an essential role in MTB-induced ERK 1/2 activation and subsequent TNF-alpha expression in monocytes/macrophages.
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Affiliation(s)
- Chul-Su Yang
- Department of Microbiology, College of Medicine, Chungnam National University, Daejeon 301-747, Seoul, Korea
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47
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Lister KJ, Hickey MJ. Immune complexes alter cerebral microvessel permeability: roles of complement and leukocyte adhesion. Am J Physiol Heart Circ Physiol 2006; 291:H694-704. [PMID: 16565304 DOI: 10.1152/ajpheart.01271.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Immune complexes (ICs) are potent inflammatory mediators in peripheral tissues. However, very few studies have examined the ability of ICs to induce inflammatory responses in the brain. Therefore, using preformed ICs or the reverse passive Arthus (RPA) model to localize ICs to the pial microvasculature of mice, we aimed to investigate the ability of ICs to induce an inflammatory response in the cerebral (pial) microvasculature. Application of preformed ICs immediately increased pial microvascular permeability, with a minimal change in leukocyte adhesion in pial postcapillary venules. In contrast, initiation of the RPA response in the pial microvasculature induced changes in cerebral microvascular permeability and increased leukocyte adhesion in pial postcapillary venules. The RPA response induced deposition of C3 in perivascular regions adjacent to sites of IC formation. Depletion of C3 abrogated RPA-induced microvascular permeability and leukocyte adhesion, indicating that the complement pathway was critical for this response. Inhibition of leukocyte adhesion via CD18 blockade also reduced IC-induced microvascular permeability. However, this did not require intercellular adhesion molecule-1, inasmuch as blockade of intercellular adhesion molecule-1 did not alter RPA-induced microvascular permeability and adhesion. These findings demonstrate that ICs are capable of rapidly inducing inflammatory responses in the cerebral microvasculature, with the complement pathway and leukocyte recruitment playing critical roles in microvascular dysfunction.
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Affiliation(s)
- Karyn J Lister
- Department of Medicine and Monash Institute of Medical Research, Monash University, Victoria, Australia
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48
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Corbett-Nelson EF, Mason D, Marshall JG, Collette Y, Grinstein S. Signaling-dependent immobilization of acylated proteins in the inner monolayer of the plasma membrane. ACTA ACUST UNITED AC 2006; 174:255-65. [PMID: 16831891 PMCID: PMC2064185 DOI: 10.1083/jcb.200605044] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phospholipids play a critical role in the recruitment and activation of several adaptors and effectors during phagocytosis. Changes in lipid metabolism during phagocytosis are restricted to the phagocytic cup, the area of the plasmalemma lining the target particle. It is unclear how specific lipids and lipid-associated molecules are prevented from diffusing away from the cup during the course of phagocytosis, a process that often requires several minutes. We studied the mobility of lipid-associated proteins at the phagocytic cup by measuring fluorescence recovery after photobleaching. Lipid-anchored (diacylated) fluorescent proteins were freely mobile in the unstimulated membrane, but their mobility was severely restricted at sites of phagocytosis. Only probes anchored to the inner monolayer displayed reduced mobility, whereas those attached to the outer monolayer were unaffected. The immobilization persisted after depletion of plasmalemmal cholesterol, ruling out a role of conventional “rafts.” Corralling of the probes by the actin cytoskeleton was similarly discounted. Instead, the change in mobility required activation of tyrosine kinases. We suggest that signaling-dependent recruitment of adaptors and effectors with lipid binding domains generates an annulus of lipids with restricted mobility.
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Affiliation(s)
- Elaine F Corbett-Nelson
- Division of Cell Biology, The Hospital for Sick Children, Department of Biochemistry, University of Toronto, M5G 1X8, Canada
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49
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Trinidad AG, de la Puerta ML, Fernández N, Bayón Y, Crespo MS, Alonso A. Coupling of C3bi to IgG inhibits the tyrosine phosphorylation signaling cascade downstream Syk and reduces cytokine induction in monocytes. J Leukoc Biol 2006; 79:1073-82. [PMID: 16501050 DOI: 10.1189/jlb.1205701] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The effect of coupling C3bi to immunoglobulin G (IgG) immune complexes (IC) on their ability to produce protein tyrosine phosphorylation and activation of the mitogen-activated protein kinase (MAPK) and the Akt/protein kinase B (PKB) routes was assessed in human monocytes. Cross-linking Fc receptors for IgG activated the protein tyrosine kinase Syk, phospholipases Cgamma1 and Cgamma2, the MAPK cascade, and the Akt/PKB route. Linkage of C3bi to the gamma-chain of IgG produced a decrease of the protein bands displaying tyrosine phosphorylation, whereas the MAPK cascades and the Akt/PKB route remained almost unaffected. Zymosan particles, which because of their beta-glucan content mimic the effect of fungi, produced a limited increase of tyrosine-phosphorylated protein bands, whereas treatment of zymosan under conditions adequate for C3bi coating increased its ability to induce protein tyrosine phosphorylation. Noteworthy, this was also observed under conditions where other components of serum might be bound by zymosan particles, for instance, serum IgG, thereby suggesting their potential involvement in Syk activation. The induction of cytokines showed a changing pattern consistent with the changes observed in the signaling pathways. IC induced monocyte chemoattractant protein-1 (MCP-1)/CC chemokine ligand 2 (CCL2), interleukin (IL)-1beta, and eotaxin-2/CCL24, which were not observed with C3bi-coated IC. Zymosan induced the expression of tumor necrosis factor alpha (TNF-alpha), TNF-beta, IL-10, IL-6, and MCP-2/CCL8, whereas the cytokine signature of C3bi-coated zymosan also included interferon-inducible protein 10/CXC chemokine ligand 10, platelet-derived growth factor-BB, and I-309/CCL1. Taken together, these findings indicate that C3bi targets the phagocytic cargo, and engagement or diversion of the Syk route determines the phagocyte response.
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Affiliation(s)
- Antonio García Trinidad
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas and Universidad de Valladolid, Spain
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50
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Ahn JY, Choi IS, Shim JY, Yun EK, Yun YS, Jeong G, Song JY. The immunomodulator ginsan induces resistance to experimental sepsis by inhibiting Toll-like receptor-mediated inflammatory signals. Eur J Immunol 2006; 36:37-45. [PMID: 16342327 DOI: 10.1002/eji.200535138] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ginsan, a polysaccharide extracted from Panax ginseng, has multiple immunomodulatory effects. In this study, we show that pretreatment of ginsan (25 mug/kg) protected mice from lethality induced by Staphylococcus aureus challenge. This survival benefit was associated with enhanced bacterial clearance from circulation, spleen and kidney. The phagocytic activity of macrophages treated with ginsan was significantly enhanced against S. aureus. However, the production of proinflammatory cytokines, such as TNF-alpha, IL-1beta, IL-6, IFN-gamma, IL-12, and IL-18, was markedly down-regulated in ginsan-treated mice compared with those of control-infected mice. The expression of Toll-like receptor (TLR) 2 and the adaptor molecule MyD88, which was greatly increased in septic macrophages, was significantly reduced by ginsan treatment in vitro. Similarly, the expression of phospho-JNK1/2, phospho-p38 MAPK, and NF-kappaB was decreased in the same culture system. These results illustrate that the antiseptic activity of ginsan can be attributed to enhanced bacterial clearance, and reduced proinflammatory cytokines via the TLR signaling pathway.
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Affiliation(s)
- Ji-Yeon Ahn
- Laboratory of Radiation Immunology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea
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