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Spiteri AG, Wishart CL, Pinget GV, Purohit SK, Macia L, King NJ, Niewold P. NK cell profiling in West Nile virus encephalitis reveals potential metabolic basis for functional inhibition. Immunol Cell Biol 2024; 102:280-291. [PMID: 38421112 DOI: 10.1111/imcb.12739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 03/02/2024]
Abstract
Natural killer (NK) cells are cytotoxic lymphocytes important for viral defense. West Nile virus (WNV) infection of the central nervous system (CNS) causes marked recruitment of bone marrow (BM)-derived monocytes, T cells and NK cells, resulting in severe neuroinflammation and brain damage. Despite substantial numbers of NK cells in the CNS, their function and phenotype remain largely unexplored. Here, we demonstrate that NK cells mature from the BM to the brain, upregulate inhibitory receptors and show reduced cytokine production and degranulation, likely due to the increased expression of the inhibitory NK cell molecule, MHC-I. Intriguingly, this correlated with a reduction in metabolism associated with cytotoxicity in brain-infiltrating NK cells. Importantly, the degranulation and killing capability were restored in NK cells isolated from WNV-infected tissue, suggesting that WNV-induced NK cell inhibition occurs in the CNS. Overall, this work identifies a potential link between MHC-I inhibition of NK cells and metabolic reduction of their cytotoxicity during infection.
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Affiliation(s)
- Alanna G Spiteri
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Claire L Wishart
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Gabriela V Pinget
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Shivam K Purohit
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Laurence Macia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia
| | - Nicholas Jc King
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia
- The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
| | - Paula Niewold
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands
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Yim KHW, Krzyzaniak O, Al Hrout A, Peacock B, Chahwan R. Assessing Extracellular Vesicles in Human Biofluids Using Flow-Based Analyzers. Adv Healthc Mater 2023; 12:e2301706. [PMID: 37800440 DOI: 10.1002/adhm.202301706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/02/2023] [Indexed: 10/07/2023]
Abstract
Extracellular vesicles (EVs) are increasingly being analyzed by flow cytometry. Yet their minuscule size and low refractive index cause the scatter intensity of most EVs to fall below the detection limit of most flow cytometers. A new class of devices, known as spectral flow analyzers, are becoming standards in cell phenotyping studies, largely due to their unique capacity to detect a vast panel of markers with higher sensitivity for light scatter detection. Another class of devices, known as nano-analyzers, provides high-resolution detection of sub-micron-sized particles. Here, the EV phenotyping performance between the Aurora (Cytek) spectral cell analyzer and the NanoFCM (nFCM) nanoflow analyzer are compared. These two devices are specifically chosen given their lead in becoming gold standards in their respective fields. Immune cell-derived EVs remain poorly characterized despite their clinical potential. Therefore, B- and T-cell line-derived EVs and donor-matched human biofluid-derived EVs from plasma, urine, and saliva are used in combination with a panel of established immune markers for this comparative study. A comparative evaluation of both cytometry platforms is performed, discussing their potential and suitability for different applications. It is found that nFCM can accurately i) analyze small EVs (40-200 nm) matching the size accuracy of electron microscopy; ii) measure the concentration of a single EV particle per volume; iii) identify underrepresented EV marker subsets; and iv) provide co-localization of EV surface markers. It can also be shown that human sample biofluids have unique EV marker signatures that can have future clinical relevance. Finally, nFCM and Aurora have their unique strength, preferred fashion of data acquisition, and visualization to fit different research interests.
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Affiliation(s)
- Kevin Ho Wai Yim
- Institute of Experimental Immunology, University of Zurich, Zurich, 8057, Switzerland
| | - Olga Krzyzaniak
- Institute of Experimental Immunology, University of Zurich, Zurich, 8057, Switzerland
| | - Ala'a Al Hrout
- Institute of Experimental Immunology, University of Zurich, Zurich, 8057, Switzerland
| | - Ben Peacock
- NanoFCM, ltd., D6 Thane Rd, Nottingham, NG90 6BH, UK
| | - Richard Chahwan
- Institute of Experimental Immunology, University of Zurich, Zurich, 8057, Switzerland
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3
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Sharp RC, Guenther DT, Farrer MJ. Experimental procedures for flow cytometry of wild-type mouse brain: a systematic review. Front Immunol 2023; 14:1281705. [PMID: 38022545 PMCID: PMC10646240 DOI: 10.3389/fimmu.2023.1281705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Objective The aim of this study was to systematically review the neuroimmunology literature to determine the average immune cell counts reported by flow cytometry in wild-type (WT) homogenized mouse brains. Background Mouse models of gene dysfunction are widely used to study age-associated neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. The importance of the neuroimmune system in these multifactorial disorders has become increasingly evident, and methods to quantify resident and infiltrating immune cells in the brain, including flow cytometry, are necessary. However, there appears to be no consensus on the best approach to perform flow cytometry or quantify/report immune cell counts. The development of more standardized methods would accelerate neuroimmune discovery and validation by meta-analysis. Methods There has not yet been a systematic review of 'neuroimmunology' by 'flow cytometry' via examination of the PROSPERO registry. A protocol for a systematic review was subsequently based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using the Studies, Data, Methods, and Outcomes (SDMO) criteria. Literature searches were conducted in the Google Scholar and PubMed databases. From that search, 900 candidate studies were identified, and 437 studies were assessed for eligibility based on formal exclusion criteria. Results Out of the 437 studies reviewed, 58 were eligible for inclusion and comparative analysis. Each study assessed immune cell subsets within homogenized mouse brains and used flow cytometry. Nonetheless, there was considerable variability in the methods, data analysis, reporting, and results. Descriptive statistics have been presented on the study designs and results, including medians with interquartile ranges (IQRs) and overall means with standard deviations (SD) for specific immune cell counts and their relative proportions, within and between studies. A total of 58 studies reported the most abundant immune cells within the brains were TMEM119+ microglia, bulk CD4+ T cells, and bulk CD8+ T cells. Conclusion Experiments to conduct and report flow cytometry data, derived from WT homogenized mouse brains, would benefit from a more standardized approach. While within-study comparisons are valid, the variability in methods of counting of immune cell populations is too broad for meta-analysis. The inclusion of a minimal protocol with more detailed methods, controls, and standards could enable this nascent field to compare results across studies.
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Affiliation(s)
| | | | - Matthew J. Farrer
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
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Uzcategui NL, Güçer S, Richter C, Speidel A, Zirdum E, Duszenko M, Garaschuk O, Figarella K. Live imaging of microglia during sleeping sickness reveals early and heterogeneous inflammatory responses. Front Immunol 2023; 14:1253648. [PMID: 37781403 PMCID: PMC10534015 DOI: 10.3389/fimmu.2023.1253648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction Invasion of the central nervous system (CNS) is the most serious consequence of Trypanosoma brucei infection, which causes sleeping sickness. Recent experimental data have revealed some more insights into the disease during the meningoencephalitic stage. However, detailed cellular processes befalling the CNS during the disease are poorly understood. Methods To further address this issue, we implanted a cranial window on the cortex of B6.129P2(Cg)-Cx3cr1tm1Litt/J mice, infected them with Trypanosoma brucei expressing RFP via intraperitoneal injection, and monitored microglial cells and parasites longitudinally over 30 days using in vivo 2-photon imaging. We correlated the observed changes with histological analyses to evaluate the recruitment of peripheral immune cells. Results and discussion We uncovered an early involvement of microglia that precedes invasion of the CNS by the parasite. We accomplished a detailed characterization of the progressive sequence of events that correlates with microglial morphological changes and microgliosis. Our findings unveiled a heterogeneous microglial response in places of initial homeostatic disruption near brain barriers and pointed out an exceptional capability of microglia to hamper parasite proliferation inside the brain. We also found early signs of inflammation in the meninges, which synchronize with the microglial response. Moreover, we observed a massive infiltration of peripheral immune cells into the parenchyma as a signature in the final disease stage. Overall, our study provides new insights into the host-pathogen immune interactions in the meningeal and parenchymal compartments of the neocortex.
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Affiliation(s)
- Nestor L. Uzcategui
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
- Institute of Anatomy, Central University of Venezuela, Caracas, Venezuela
| | - Sena Güçer
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Cris Richter
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Annika Speidel
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Elizabeta Zirdum
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Michael Duszenko
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Katherine Figarella
- Department of Neurophysiology, Institute of Physiology, University of Tuebingen, Tuebingen, Germany
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Gao W, Jin X, Zhou P, Zhu H, Xie K, Jin B, Du L. Relationship between Uveitis and the Differential Reactivity of Retinal Microglia. Ophthalmic Res 2023; 66:1206-1212. [PMID: 37666222 PMCID: PMC10614524 DOI: 10.1159/000531156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/09/2023] [Indexed: 09/06/2023]
Abstract
Uveitis, a complicated group of ocular inflammatory diseases, can be affected by massive pathogenic contributors such as infection, autoimmunity, and genetics. Although it is well known that many pathological changes, including disorders of the immune system and disruption of the blood-retinal barrier, count much in the onset and progression of uveitis, there is a paucity of safe and effective treatments, which has exceedingly hindered the appropriate treatment of uveitis. As innate immune cells in the retina, microglia occupy a salient position in retinal homeostasis. Many studies have reported the activation of microglia in uveitis and the mitigation of uveitis by interfering with microglial reactivity, which strongly implicates microglia as a therapeutic target. However, it has been increasingly recognized that microglia are a nonhomogeneous population under different physiological and pathological conditions, which makes it essential to thoroughly have knowledge of their specific characteristics. The paper outlines the various properties of activated microglia in uveitis, summarizes the connections between their polarization patterns and the manifestations of uveitis, and ultimately is intended to enhance the understanding of microglial versatility and expedite the exploration of promising strategies for visual protection.
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Affiliation(s)
- Wenna Gao
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xuemin Jin
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Pengyi Zhou
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Haiyan Zhu
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Kunpeng Xie
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bo Jin
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Liping Du
- Department of Ophthalmology, Henan International Joint Research Laboratory for Ocular Immunology and Retinal Injury Repair, Henan Province Eye Hospital, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Thammahakin P, Maezono K, Maekawa N, Kariwa H, Kobayashi S. Detection of disease-associated microglia among various microglia phenotypes induced by West Nile virus infection in mice. J Neurovirol 2023; 29:367-375. [PMID: 37552415 DOI: 10.1007/s13365-023-01161-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/06/2023] [Accepted: 07/19/2023] [Indexed: 08/09/2023]
Abstract
West Nile virus (WNV) has emerged as a significant cause of viral encephalitis in humans and horses. However, the pathogenesis of the West Nile encephalitis remains unclear. Microglia are activated by WNV infection, and the pathogenic involvement of their phenotypes is controversial. In this study, we examined the diversity of microglia phenotypes caused by WNV infection by assessing various microglia markers and identified disease-associated microglia in WNV-infected mouse brain tissue. Cells positive for general microglia markers such as Iba1, P2RY12, or TMEM119 were detected in the control and WNV-infected brain tissue. The morphology of the positive cells in brain tissue infected by WNV was different from that of control brain tissue, indicating that WNV infection induced activation of microglia. The activated microglia were classified into various phenotypes by investigation of specific marker expression. Among the activated microglia, disease-associated microglia that were positive for CD11c and weakly positive for TMEM119 were detected close to the WNV-infected cells. These results indicate that WNV infection induces activation of diverse microglia phenotypes and that disease-associated microglia may be associated with the pathogenicity of WNV infection in the mouse brain.
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Affiliation(s)
- Passawat Thammahakin
- Laboratory of Public Health, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Keisuke Maezono
- Laboratory of Public Health, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Naoya Maekawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroaki Kariwa
- Laboratory of Public Health, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shintaro Kobayashi
- Laboratory of Public Health, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
- Institute for Vaccine Research and Development (HU-IVReD), Hokkaido University, Sapporo, Japan.
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Spiteri AG, van Vreden C, Ashhurst TM, Niewold P, King NJC. Clodronate is not protective in lethal viral encephalitis despite substantially reducing inflammatory monocyte infiltration in the CNS. Front Immunol 2023; 14:1203561. [PMID: 37545511 PMCID: PMC10403146 DOI: 10.3389/fimmu.2023.1203561] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/30/2023] [Indexed: 08/08/2023] Open
Abstract
Bone marrow (BM)-derived monocytes induce inflammation and tissue damage in a range of pathologies. In particular, in a mouse model of West Nile virus (WNV) encephalitis (WNE), nitric oxide-producing, Ly6Chi inflammatory monocytes from the BM are recruited to the central nervous system (CNS) and contribute to lethal immune pathology. Reducing the migration of these cells into the CNS using monoclonal antibody blockade, immune-modifying particles or CSF-1R inhibitors reduces neuroinflammation, improving survival and/or clinical outcomes. Macrophages can also be targeted more broadly by administration of clodronate-encapsulated liposomes, which induce apoptosis in phagocytes. In this study, clodronate reduced the inflammatory infiltrate by 70% in WNE, however, surprisingly, this had no effect on disease outcome. More detailed analysis demonstrated a compensatory increase in neutrophils and enhanced activation status of microglia in the brain. In addition, we observed increased numbers of Ly6Chi BM monocytes with an increased proliferative capacity and expression of SCA-1 and CD16/32, potentially indicating output of immature cells from the BM. Once in the brain, these cells were more phagocytic and had a reduced expression of antigen-presenting molecules. Lastly, we show that clodronate also reduces non-myeloid cells in the spleen and BM, as well as ablating red blood cells and their proliferation. These factors likely impeded the therapeutic potential of clodronate in WNE. Thus, while clodronate provides an excellent system to deplete macrophages in the body, it has larger and broader effects on the phagocytic and non-phagocytic system, which must be considered in the interpretation of data.
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Affiliation(s)
- Alanna G. Spiteri
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Caryn van Vreden
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Thomas M. Ashhurst
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia
| | - Paula Niewold
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden, Netherlands
| | - Nicholas J. C. King
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia
- The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
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Sunna S, Bowen CA, Ramelow CC, Santiago JV, Kumar P, Rangaraju S. Advances in proteomic phenotyping of microglia in neurodegeneration. Proteomics 2023; 23:e2200183. [PMID: 37060300 PMCID: PMC10528430 DOI: 10.1002/pmic.202200183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/16/2023]
Abstract
Microglia are dynamic resident immune cells of the central nervous system (CNS) that sense, survey, and respond to changes in their environment. In disease states, microglia transform from homeostatic to diverse molecular phenotypic states that play complex and causal roles in neurologic disease pathogenesis, as evidenced by the identification of microglial genes as genetic risk factors for neurodegenerative disease. While advances in transcriptomic profiling of microglia from the CNS of humans and animal models have provided transformative insights, the transcriptome is only modestly reflective of the proteome. Proteomic profiling of microglia is therefore more likely to provide functionally and therapeutically relevant targets. In this review, we discuss molecular insights gained from transcriptomic studies of microglia in the context of Alzheimer's disease as a prototypic neurodegenerative disease, and highlight existing and emerging approaches for proteomic profiling of microglia derived from in vivo model systems and human brain.
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Affiliation(s)
- Sydney Sunna
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
| | - Christine A. Bowen
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
- Department of Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Christina C. Ramelow
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
| | - Juliet V. Santiago
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
| | - Prateek Kumar
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
| | - Srikant Rangaraju
- Department of Neurology, Emory University,201 Dowman Drive Atlanta Georgia, 30322, United States of America
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA
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Spiteri AG, Wishart CL, Ni D, Viengkhou B, Macia L, Hofer MJ, King NJC. Temporal tracking of microglial and monocyte single-cell transcriptomics in lethal flavivirus infection. Acta Neuropathol Commun 2023; 11:60. [PMID: 37016414 PMCID: PMC10074823 DOI: 10.1186/s40478-023-01547-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/08/2023] [Indexed: 04/06/2023] Open
Abstract
As the resident parenchymal myeloid population in the central nervous system (CNS), microglia are strategically positioned to respond to neurotropic virus invasion and have been implicated in promoting both disease resolution and progression in the acute and post-infectious phase of virus encephalitis. In a mouse model of West Nile virus encephalitis (WNE), infection of the CNS results in recruitment of large numbers of peripheral immune cells into the brain, the majority being nitric oxide (NO)-producing Ly6Chi inflammatory monocyte-derived cells (MCs). In this model, these cells enhance immunopathology and mortality. However, the contribution of microglia to this response is currently undefined. Here we used a combination of experimental tools, including single-cell RNA sequencing (scRNA-seq), microglia and MC depletion reagents, high-dimensional spectral cytometry and computational algorithms to dissect the differential contribution of microglia and MCs to the anti-viral immune response in severe neuroinflammation seen in WNE. Intriguingly, analysis of scRNA-seq data revealed 6 unique microglia and 3 unique MC clusters that were predominantly timepoint-specific, demonstrating substantial transcriptional adaptation with disease progression over the course of WNE. While microglia and MC adopted unique gene expression profiles, gene ontology enrichment analysis, coupled with microglia and MC depletion studies, demonstrated a role for both of these cells in the trafficking of peripheral immune cells into the CNS, T cell responses and viral clearance. Over the course of infection, microglia transitioned from a homeostatic to an anti-viral and then into an immune cell-recruiting phenotype. Conversely, MC adopted antigen-presenting, immune cell-recruiting and NO-producing phenotypes, which all had anti-viral function. Overall, this study defines for the first time the single-cell transcriptomic responses of microglia and MCs over the course of WNE, demonstrating both protective and pathological roles of these cells that could potentially be targeted for differential therapeutic intervention to dampen immune-mediated pathology, while maintaining viral clearance functions.
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Affiliation(s)
- Alanna G Spiteri
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia
- Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Claire L Wishart
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia
- Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Duan Ni
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
- Chronic Diseases Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Barney Viengkhou
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Laurence Macia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
- Chronic Diseases Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Markus J Hofer
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
- The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Nicholas J C King
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia.
- Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, 2006, Australia.
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia.
- The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, 2006, Australia.
- Sydney Nano, The University of Sydney, Sydney, NSW, 2006, Australia.
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10
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Wishart CL, Spiteri AG, Locatelli G, King NJC. Integrating transcriptomic datasets across neurological disease identifies unique myeloid subpopulations driving disease-specific signatures. Glia 2023; 71:904-925. [PMID: 36527260 PMCID: PMC10952672 DOI: 10.1002/glia.24314] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/06/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
Microglia and bone marrow-derived monocytes are key elements of central nervous system (CNS) inflammation, both capable of enhancing and dampening immune-mediated pathology. However, the study-specific focus on individual cell types, disease models or experimental approaches has limited our ability to infer common and disease-specific responses. This meta-analysis integrates bulk and single-cell transcriptomic datasets of microglia and monocytes from disease models of autoimmunity, neurodegeneration, sterile injury, and infection to build a comprehensive resource connecting myeloid responses across CNS disease. We demonstrate that the bulk microglial and monocyte program is highly contingent on the disease environment, challenging the notion of a universal microglial disease signature. Integration of six single-cell RNA-sequencing datasets revealed that these disease-specific signatures are likely driven by differing proportions of unique myeloid subpopulations that were individually expanded in different disease settings. These subsets were functionally-defined as neurodegeneration-associated, inflammatory, interferon-responsive, phagocytic, antigen-presenting, and lipopolysaccharide-responsive cellular states, revealing a core set of myeloid responses at the single-cell level that are conserved across CNS pathology. Showcasing the predictive and practical value of this resource, we performed differential expression analysis on microglia and monocytes across disease and identified Cd81 as a new neuroinflammatory-stable gene that accurately identified microglia and distinguished them from monocyte-derived cells across all experimental models at both the bulk and single-cell level. Together, this resource dissects the influence of disease environment on shared immune response programmes to build a unified perspective of myeloid behavior across CNS pathology.
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Affiliation(s)
- Claire L. Wishart
- Infection, Immunity, Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- Sydney Cytometry FacilityThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Ramaciotti Facility for Human Systems BiologyThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Charles Perkins CentreThe University of SydneySydneyNew South WalesAustralia
| | - Alanna G. Spiteri
- Infection, Immunity, Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- Sydney Cytometry FacilityThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Ramaciotti Facility for Human Systems BiologyThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Charles Perkins CentreThe University of SydneySydneyNew South WalesAustralia
| | - Giuseppe Locatelli
- Theodor Kocher InstituteUniversity of BernBernSwitzerland
- Novartis Institutes for BioMedical ResearchNovartisBaselSwitzerland
| | - Nicholas J. C. King
- Infection, Immunity, Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- Sydney Cytometry FacilityThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Ramaciotti Facility for Human Systems BiologyThe University of Sydney and Centenary InstituteSydneyNew South WalesAustralia
- Charles Perkins CentreThe University of SydneySydneyNew South WalesAustralia
- Sydney Institute for Infectious Diseases, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
- The University of Sydney Nano Institute, Faculty of ScienceThe University of SydneySydneyNew South WalesAustralia
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11
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Teo JD, Marian OC, Spiteri AG, Nicholson M, Song H, Khor JXY, McEwen HP, Ge A, Sen MK, Piccio L, Fletcher JL, King NJC, Murray SS, Brüning JC, Don AS. Early microglial response, myelin deterioration and lethality in mice deficient for very long chain ceramide synthesis in oligodendrocytes. Glia 2023; 71:1120-1141. [PMID: 36583573 PMCID: PMC10952316 DOI: 10.1002/glia.24329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 11/05/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022]
Abstract
The sphingolipids galactosylceramide (GalCer), sulfatide (ST) and sphingomyelin (SM) are essential for myelin stability and function. GalCer and ST are synthesized mostly from C22-C24 ceramides, generated by Ceramide Synthase 2 (CerS2). To clarify the requirement for C22-C24 sphingolipid synthesis in myelin biosynthesis and stability, we generated mice lacking CerS2 specifically in myelinating cells (CerS2ΔO/ΔO ). At 6 weeks of age, normal-appearing myelin had formed in CerS2ΔO/ΔO mice, however there was a reduction in myelin thickness and the percentage of myelinated axons. Pronounced loss of C22-C24 sphingolipids in myelin of CerS2ΔO/ΔO mice was compensated by greatly increased levels of C18 sphingolipids. A distinct microglial population expressing high levels of activation and phagocytic markers such as CD64, CD11c, MHC class II, and CD68 was apparent at 6 weeks of age in CerS2ΔO/ΔO mice, and had increased by 10 weeks. Increased staining for denatured myelin basic protein was also apparent in 6-week-old CerS2ΔO/ΔO mice. By 16 weeks, CerS2ΔO/ΔO mice showed pronounced myelin atrophy, motor deficits, and axon beading, a hallmark of axon stress. 90% of CerS2ΔO/ΔO mice died between 16 and 26 weeks of age. This study highlights the importance of sphingolipid acyl chain length for the structural integrity of myelin, demonstrating how a modest reduction in lipid chain length causes exposure of a denatured myelin protein epitope and expansion of phagocytic microglia, followed by axon pathology, myelin degeneration, and motor deficits. Understanding the molecular trigger for microglial activation should aid the development of therapeutics for demyelinating and neurodegenerative diseases.
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Affiliation(s)
- Jonathan D. Teo
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Oana C. Marian
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Alanna G. Spiteri
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Madeline Nicholson
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Huitong Song
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Jasmine X. Y. Khor
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Holly P. McEwen
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Anjie Ge
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Monokesh K. Sen
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Laura Piccio
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
- Department of NeurologyWashington University School of MedicineSt LouisMissouriUSA
| | - Jessica L. Fletcher
- Menzies Institute for Medical ResearchThe University of TasmaniaHobartTasmaniaAustralia
| | - Nicholas J. C. King
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
| | - Simon S. Murray
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | | | - Anthony S. Don
- Charles Perkins Centre and School of Medical SciencesThe University of SydneyCamperdownNew South WalesAustralia
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12
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Spiteri AG, King NJ. Putting PLX5622 into perspective: microglia in central nervous system viral infection. Neural Regen Res 2022; 18:1269-1270. [PMID: 36453408 PMCID: PMC9838161 DOI: 10.4103/1673-5374.360170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Alanna G. Spiteri
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia,Charles Perkins Centre, The University of Sydney, Australia
| | - Nicholas J.C. King
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia,Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia,Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, Australia,Charles Perkins Centre, The University of Sydney, Australia,The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia,The University of Sydney Nano Institute, the University of Sydney, Sydney, NSW, Australia,Correspondence to: Nicholas J.C. King, .
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13
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Spiteri AG, Ni D, Ling ZL, Macia L, Campbell IL, Hofer MJ, King NJC. PLX5622 Reduces Disease Severity in Lethal CNS Infection by Off-Target Inhibition of Peripheral Inflammatory Monocyte Production. Front Immunol 2022; 13:851556. [PMID: 35401512 PMCID: PMC8990748 DOI: 10.3389/fimmu.2022.851556] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/03/2022] [Indexed: 11/18/2022] Open
Abstract
PLX5622 is a CSF-1R inhibitor and microglia-depleting reagent, widely used to investigate the biology of this central nervous system (CNS)-resident myeloid population, but the indirect or off-target effects of this agent remain largely unexplored. In a murine model of severe neuroinflammation induced by West Nile virus encephalitis (WNE), we showed PLX5622 efficiently depleted both microglia and a sub-population of border-associated macrophages in the CNS. However, PLX5622 also significantly depleted mature Ly6Chi monocytes in the bone marrow (BM), inhibiting their proliferation and lethal recruitment into the infected brain, reducing neuroinflammation and clinical disease scores. Notably, in addition, BM dendritic cell subsets, plasmacytoid DC and classical DC, were depleted differentially in infected and uninfected mice. Confirming its protective effect in WNE, cessation of PLX5622 treatment exacerbated disease scores and was associated with robust repopulation of microglia, rebound BM monopoiesis and markedly increased inflammatory monocyte infiltration into the CNS. Monoclonal anti-CSF-1R antibody blockade late in WNE also impeded BM monocyte proliferation and recruitment to the brain, suggesting that the protective effect of PLX5622 is via the inhibition of CSF-1R, rather than other kinase targets. Importantly, BrdU incorporation in PLX5622-treated mice, suggest remaining microglia proliferate independently of CSF-1 in WNE. Our study uncovers significantly broader effects of PLX5622 on the myeloid lineage beyond microglia depletion, advising caution in the interpretation of PLX5622 data as microglia-specific. However, this work also strikingly demonstrates the unexpected therapeutic potential of this molecule in CNS viral infection, as well as other monocyte-mediated diseases.
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Affiliation(s)
- Alanna G Spiteri
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Duan Ni
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.,Chronic Diseases Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Zheng Lung Ling
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
| | - Laurence Macia
- Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.,Chronic Diseases Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Iain L Campbell
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Markus J Hofer
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia.,The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia
| | - Nicholas J C King
- Viral Immunopathology Laboratory, Infection, Immunity and Inflammation Research Theme, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Sydney Cytometry, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Ramaciotti Facility for Human Systems Biology, The University of Sydney and Centenary Institute, Sydney, NSW, Australia.,Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.,The University of Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia.,The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, Australia
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14
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Ni D, Tan J, Niewold P, Spiteri AG, Pinget GV, Stanley D, King NJC, Macia L. Impact of Dietary Fiber on West Nile Virus Infection. Front Immunol 2022; 13:784486. [PMID: 35296081 PMCID: PMC8919037 DOI: 10.3389/fimmu.2022.784486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/04/2022] [Indexed: 12/11/2022] Open
Abstract
Dietary fiber supports healthy gut bacteria and their production of short-chain fatty acids (SCFA), which promote anti-inflammatory cell development, in particular, regulatory T cells. It is thus beneficial in many diseases, including influenza infection. While disruption of the gut microbiota by antibiotic treatment aggravates West Nile Virus (WNV) disease, whether dietary fiber is beneficial is unknown. WNV is a widely-distributed neurotropic flavivirus that recruits inflammatory monocytes into the brain, causing life-threatening encephalitis. To investigate the impact of dietary fiber on WNV encephalitis, mice were fed on diets deficient or enriched with dietary fiber for two weeks prior to inoculation with WNV. To induce encephalitis, mice were inoculated intranasally with WNV and maintained on these diets. Despite increased fecal SCFA acetate and changes in gut microbiota composition, dietary fiber did not affect clinical scores, leukocyte infiltration into the brain, or survival. After the brain, highest virus loads were measured in the colon in neurons of the submucosal and myenteric plexuses. Associated with this, there was disrupted gut homeostasis, with shorter colon length and higher local inflammatory cytokine levels, which were not affected by dietary fiber. Thus, fiber supplementation is not effective in WNV encephalitis.
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Affiliation(s)
- Duan Ni
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Jian Tan
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Paula Niewold
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden, Netherlands
| | - Alanna Gabrielle Spiteri
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Gabriela Veronica Pinget
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Dragana Stanley
- School of Health, Medical and Applied Science, Central Queensland University, Rockhampton, QLD, Australia
| | - Nicholas Jonathan Cole King
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW, Australia
- *Correspondence: Nicholas Jonathan Cole King, ; Laurence Macia,
| | - Laurence Macia
- Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Sydney Cytometry, The University of Sydney and The Centenary Institute, Sydney, NSW, Australia
- *Correspondence: Nicholas Jonathan Cole King, ; Laurence Macia,
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15
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Spiteri AG, Wishart CL, Pamphlett R, Locatelli G, King NJC. Microglia and monocytes in inflammatory CNS disease: integrating phenotype and function. Acta Neuropathol 2022; 143:179-224. [PMID: 34853891 PMCID: PMC8742818 DOI: 10.1007/s00401-021-02384-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 02/08/2023]
Abstract
In neurological diseases, the actions of microglia, the resident myeloid cells of the CNS parenchyma, may diverge from, or intersect with, those of recruited monocytes to drive immune-mediated pathology. However, defining the precise roles of each cell type has historically been impeded by the lack of discriminating markers and experimental systems capable of accurately identifying them. Our ability to distinguish microglia from monocytes in neuroinflammation has advanced with single-cell technologies, new markers and drugs that identify and deplete them, respectively. Nevertheless, the focus of individual studies on particular cell types, diseases or experimental approaches has limited our ability to connect phenotype and function more widely and across diverse CNS pathologies. Here, we critically review, tabulate and integrate the disease-specific functions and immune profiles of microglia and monocytes to provide a comprehensive atlas of myeloid responses in viral encephalitis, demyelination, neurodegeneration and ischemic injury. In emphasizing the differential roles of microglia and monocytes in the severe neuroinflammatory disease of viral encephalitis, we connect inflammatory pathways common to equally incapacitating diseases with less severe inflammation. We examine these findings in the context of human studies and highlight the benefits and inherent limitations of animal models that may impede or facilitate clinical translation. This enables us to highlight common and contrasting, non-redundant and often opposing roles of microglia and monocytes in disease that could be targeted therapeutically.
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