1
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Kann O, Almouhanna F, Chausse B. Interferon γ: a master cytokine in microglia-mediated neural network dysfunction and neurodegeneration. Trends Neurosci 2022; 45:913-927. [PMID: 36283867 DOI: 10.1016/j.tins.2022.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022]
Abstract
Traditionally, lymphocytic interferon γ (IFN-γ) was considered to be a simple 'booster' of proinflammatory responses by microglia (brain-resident macrophages) during bacterial or viral infection. Recent slice culture (in situ) and in vivo studies suggest, however, that IFN-γ has a unique role in microglial activation. Priming by IFN-γ results in proliferation (microgliosis), enhanced synapse elimination, and moderate nitric oxide release sufficient to impair synaptic transmission, gamma rhythm activity, and cognitive functions. Moreover, IFN-γ is pivotal for driving Toll-like receptor (TLR)-activated microglia into neurotoxic phenotypes that induce energetic and oxidative stress, severe network dysfunction, and neuronal death. Pharmacological targeting of activated microglia could be beneficial during elevated IFN-γ levels, blood-brain barrier leakage, and parenchymal T lymphocyte infiltration associated with, for instance, encephalitis, multiple sclerosis, and Alzheimer's disease.
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Affiliation(s)
- Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, D-69120 Heidelberg, Germany; Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, D-69120 Heidelberg, Germany.
| | - Fadi Almouhanna
- Institute of Physiology and Pathophysiology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Bruno Chausse
- Institute of Physiology and Pathophysiology, University of Heidelberg, D-69120 Heidelberg, Germany
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2
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Mix MR, Harty JT. Keeping T cell memories in mind. Trends Immunol 2022; 43:1018-1031. [PMID: 36369103 PMCID: PMC9691610 DOI: 10.1016/j.it.2022.10.001] [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: 09/01/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/09/2022]
Abstract
The mammalian central nervous system (CNS) contains a vibrant community of resident adaptive immune cells at homeostasis. Among these are memory CD8+ and CD4+ T cells, which reside in the CNS in the settings of health, aging, and neurological disease. These T cells commonly exhibit a tissue-resident memory (TRM) phenotype, suggesting that they are antigen-experienced and remain separate from the circulation. Despite these characterizations, T cell surveillance of the CNS has only recently been studied through the lens of TRM immunology. In this Review, we outline emerging concepts of CNS TRM generation, localization, maintenance, function, and specificity. In this way, we hope to highlight roles of CNS TRM in health and disease to inform future studies of adaptive neuroimmunity.
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Affiliation(s)
- Madison R Mix
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, USA
| | - John T Harty
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Medical Scientist Training Program, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, USA.
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3
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Claes C, England WE, Danhash EP, Kiani Shabestari S, Jairaman A, Chadarevian JP, Hasselmann J, Tsai AP, Coburn MA, Sanchez J, Lim TE, Hidalgo JLS, Tu C, Cahalan MD, Lamb BT, Landreth GE, Spitale RC, Blurton‐Jones M, Davtyan H. The P522R protective variant of PLCG2 promotes the expression of antigen presentation genes by human microglia in an Alzheimer's disease mouse model. Alzheimers Dement 2022; 18:1765-1778. [PMID: 35142046 PMCID: PMC9360195 DOI: 10.1002/alz.12577] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 01/28/2023]
Abstract
The P522R variant of PLCG2, expressed by microglia, is associated with reduced risk of Alzheimer's disease (AD). Yet, the impact of this protective mutation on microglial responses to AD pathology remains unknown. Chimeric AD and wild-type mice were generated by transplanting PLCG2-P522R or isogenic wild-type human induced pluripotent stem cell microglia. At 7 months of age, single-cell and bulk RNA sequencing, and histological analyses were performed. The PLCG2-P522R variant induced a significant increase in microglial human leukocyte antigen (HLA) expression and the induction of antigen presentation, chemokine signaling, and T cell proliferation pathways. Examination of immune-intact AD mice further demonstrated that the PLCG2-P522R variant promotes the recruitment of CD8+ T cells to the brain. These data provide the first evidence that the PLCG2-P522R variant increases the capacity of microglia to recruit T cells and present antigens, promoting a microglial transcriptional state that has recently been shown to be reduced in AD patient brains.
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Affiliation(s)
- Christel Claes
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
| | - Whitney E. England
- Department of Pharmaceutical Sciences University of CaliforniaIrvineCaliforniaUSA
| | - Emma P. Danhash
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
| | - Sepideh Kiani Shabestari
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Amit Jairaman
- Department of Physiology and BiophysicsUniversity of California IrvineIrvineCaliforniaUSA
| | - Jean Paul Chadarevian
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Jonathan Hasselmann
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Andy P. Tsai
- Stark Neurosciences Research InstituteIUSMIndianapolisIndianaUSA
| | - Morgan A. Coburn
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Jessica Sanchez
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Tau En Lim
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
| | - Jorge L. S. Hidalgo
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
| | - Christina Tu
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
| | - Michael D. Cahalan
- Department of Physiology and BiophysicsUniversity of California IrvineIrvineCaliforniaUSA
| | - Bruce T. Lamb
- Stark Neurosciences Research InstituteIUSMIndianapolisIndianaUSA
- Department of Medical and Molecular GeneticsIUSMIndianapolisIndianaUSA
| | - Gary E. Landreth
- Stark Neurosciences Research InstituteIUSMIndianapolisIndianaUSA
- Department of Anatomy and Cell BiologyIUSMIndianapolisIndianaUSA
| | - Robert C. Spitale
- Department of Pharmaceutical Sciences University of CaliforniaIrvineCaliforniaUSA
| | - Mathew Blurton‐Jones
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of California IrvineIrvineCaliforniaUSA
| | - Hayk Davtyan
- Institute for Memory Impairments and Neurological DisordersUniversity of California IrvineIrvineCaliforniaUSA
- Sue and Bill Gross Stem Cell Research CenterUniversity of California IrvineIrvineCaliforniaUSA
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4
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Prasad S, Sheng WS, Hu S, Chauhan P, Lokensgard JR. Dysregulated Microglial Cell Activation and Proliferation Following Repeated Antigen Stimulation. Front Cell Neurosci 2021; 15:686340. [PMID: 34447297 PMCID: PMC8383069 DOI: 10.3389/fncel.2021.686340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/16/2021] [Indexed: 12/16/2022] Open
Abstract
Upon reactivation of quiescent neurotropic viruses antigen (Ag)-specific brain resident-memory CD8+ T-cells (bTRM) may respond to de novo-produced viral Ag through the rapid release of IFN-γ, which drives subsequent interferon-stimulated gene expression in surrounding microglia. Through this mechanism, a small number of adaptive bTRM may amplify responses to viral reactivation leading to an organ-wide innate protective state. Over time, this brain-wide innate immune activation likely has cumulative neurotoxic and neurocognitive consequences. We have previously shown that HIV-1 p24 Ag-specific bTRM persist within the murine brain using a heterologous prime-CNS boost strategy. In response to Ag restimulation, these bTRM display rapid and robust recall responses, which subsequently activate glial cells. In this study, we hypothesized that repeated challenges to viral antigen (Ag) (modeling repeated episodes of viral reactivation) culminate in prolonged reactive gliosis and exacerbated neurotoxicity. To address this question, mice were first immunized with adenovirus vectors expressing the HIV p24 capsid protein, followed by a CNS-boost using Pr55Gag/Env virus-like particles (HIV-VLPs). Following the establishment of the bTRM population [>30 days (d)], prime-CNS boost animals were then subjected to in vivo challenge, as well as re-challenge (at 14 d post-challenge), using the immunodominant HIV-1 AI9 CD8+ T-cell epitope peptide. In these studies, Ag re-challenge resulted in prolonged expression of microglial activation markers and an increased proliferative response, longer than the challenge group. This continued expression of MHCII and PD-L1 (activation markers), as well as Ki67 (proliferative marker), was observed at 7, 14, and 30 days post-AI9 re-challenge. Additionally, in vivo re-challenge resulted in continued production of inducible nitric oxide synthase (iNOS) with elevated levels observed at 7, 14 and 30 days post re-challenge. Interestingly, iNOS expression was significantly lower among challenged animals when compared to re-challenged groups. Furthermore, in vivo specific Ag re-challenge produced lower levels of arginase (Arg)-1 when compared with the challenged group. Taken together, these results indicate that repeated Ag-specific stimulation of adaptive immune responses leads to cumulative dysregulated microglial cell activation.
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Affiliation(s)
- Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
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5
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Chauhan P, Hu S, Prasad S, Sheng WS, Lokensgard JR. Programmed death ligand-1 induction restrains the cytotoxic T lymphocyte response against microglia. Glia 2020; 69:858-871. [PMID: 33128485 DOI: 10.1002/glia.23932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 10/15/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022]
Abstract
Microglial cells are the main reservoir for HIV-1 within the brain and potential exists for negative immune checkpoint blockade therapies to purge this viral reservoir. Here, we investigated cytolytic responses of CD8+ T lymphocytes against microglia loaded with peptide epitopes. Initially, flow cytometric analysis demonstrated efficient killing of HIV-1 p24 AI9 or YI9 peptide-loaded splenocytes in MHC-matched recipients. Cytolytic killing of microglia was first demonstrated using ovalbumin (OVA) as a model antigen for in vitro cytotoxic T lymphocyte (CTL) assays. Peptide-loaded primary microglia obtained from programmed death ligand (PD-L) 1 knockout (KO) animals showed significantly more killing than cells from wild-type (WT) animals when co-cultured with activated CD8+ T-cells isolated from rAd5-OVA primed animals. Moreover, when peptide loaded-microglial cells from WT animals were treated with neutralizing α-PD-L1 Ab, significantly more killing was observed compared to either untreated or IgG isotype-treated cells. Most importantly, significantly increased in vivo killing of HIV-1 p24 YI9 peptide-loaded microglia from PD-L1 KO animals, as well as AI9 peptide-loaded BALB/c microglial cells treated with α-PD-L1, was observed within brains of rAd5-p24 primed-CNS boosted C57BL/6 or BALB/c mice, respectively. Finally, ex vivo responses of brain CD8+ T-cells in response to AI9 stimulation showed significantly increased IFN-γ and IL-2 production when treated with α-PD-1 Abs. Greater proliferation of CD8+ T-cells from the brain was also observed following blockade. Taken together, these studies demonstrate that PD-L1 induction on microglia restrains CTL responses and indicate that immune checkpoint blockade targeting this pathway may be beneficial in clearing viral brain reservoirs.
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Affiliation(s)
- Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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6
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Ní Chasaide C, Lynch MA. The role of the immune system in driving neuroinflammation. Brain Neurosci Adv 2020; 4:2398212819901082. [PMID: 32219178 PMCID: PMC7085916 DOI: 10.1177/2398212819901082] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/23/2019] [Indexed: 12/11/2022] Open
Abstract
Neuroinflammation is now recognised as an important contributory factor in the progression of Alzheimer’s disease and probably also in the early stages of the disease. It is likely that this derives largely from aberrant activation of microglia, the resident mononuclear phagocytes of the brain. These cells are responsible for physiological immune surveillance and clearance of pathogens in the central nervous system, but evidence indicates that in Alzheimer’s disease, microglial function is compromised, and this contributes to the pathology. It is unclear what factors cause the inappropriate activation of the microglia in Alzheimer’s disease, but one contributor may be infiltrating peripheral immune cells and these include macrophages and T cells. It has been suggested that both cell types modulate the phenotype of microglia, highlighting the importance of crosstalk between the innate and adaptive immune system in Alzheimer’s disease. This review outlines our current knowledge of how cells of the peripheral immune system, specifically macrophages and T cells, may modulate microglial phenotype in the context of Alzheimer’s disease and considers the impact on their function, especially phagocytic capacity.
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Affiliation(s)
| | - Marina A Lynch
- Marina A Lynch, Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin 2, Ireland.
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7
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Prasad S, Hu S, Sheng WS, Chauhan P, Lokensgard JR. Recall Responses from Brain-Resident Memory CD8 + T Cells (bT RM) Induce Reactive Gliosis. iScience 2019; 20:512-526. [PMID: 31655062 PMCID: PMC6807101 DOI: 10.1016/j.isci.2019.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/26/2019] [Accepted: 09/30/2019] [Indexed: 01/24/2023] Open
Abstract
HIV-associated neurocognitive disorders (HAND) persist even during effective combination antiretroviral therapy (cART). Although the cause of HAND is unknown, studies link chronic immune activation, neuroinflammation, and cerebrospinal fluid viral escape to disease progression. In this study, we tested the hypothesis that specific, recall immune responses from brain-resident memory T cells (bTRM) could activate glia and induce neurotoxic mediators. To address this question, we developed a heterologous prime-central nervous system (CNS) boost strategy in mice. We observed that the murine brain became populated with long-lived CD8+ bTRM, some being specific for an immunodominant Gag epitope. Recall stimulation using HIV-1 AI9 peptide administered in vivo resulted in microglia displaying elevated levels of major histocompatibility complex class II and programmed death-ligand 1, and demonstrating tissue-wide reactive gliosis. Immunostaining further confirmed this glial activation. Taken together, these results indicate that specific, adaptive recall responses from bTRM can induce reactive gliosis and production of neurotoxic mediators. Heterologous prime-CNS boost induced HIV-1-specific bTRM, which persisted long term Recall responses from HIV-specific bTRM induced tissue-wide reactive gliosis bTRM induced-reactive gliosis likely has cumulative neurotoxic consequences
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Affiliation(s)
- Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-107 Microbiology Research Facility, 689 23(rd) Avenue S.E., Minneapolis, MN 55455, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-107 Microbiology Research Facility, 689 23(rd) Avenue S.E., Minneapolis, MN 55455, USA
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-107 Microbiology Research Facility, 689 23(rd) Avenue S.E., Minneapolis, MN 55455, USA
| | - Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-107 Microbiology Research Facility, 689 23(rd) Avenue S.E., Minneapolis, MN 55455, USA
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-107 Microbiology Research Facility, 689 23(rd) Avenue S.E., Minneapolis, MN 55455, USA.
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8
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Antiallodynic Effects of Cannabinoid Receptor 2 (CB 2R) Agonists on Retrovirus Infection-Induced Neuropathic Pain. Pain Res Manag 2019; 2019:1260353. [PMID: 31354896 PMCID: PMC6637694 DOI: 10.1155/2019/1260353] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
Abstract
The most common neurological complication in patients receiving successful combination antiretroviral therapy (cART) is peripheral neuropathic pain. Data show that distal symmetric polyneuropathy (DSP) also develops along with murine acquired immunodeficiency syndrome (MAIDS) after infection with the LP-BM5 murine retrovirus mixture. Links between cannabinoid receptor 2 (CB2R) and peripheral neuropathy have been established in animal models using nerve transection, chemotherapy-induced pain, and various other stimuli. Diverse types of neuropathic pain respond differently to standard drug intervention, and little is currently known regarding the effects of modulation through CB2Rs. In this study, we evaluated whether treatment with the exogenous synthetic CB2R agonists JWH015, JWH133, Gp1a, and HU308 controls neuropathic pain and neuroinflammation in animals with chronic retroviral infection. Hind-paw mechanical hypersensitivity in CB2R agonist-treated versus untreated animals was assessed using the MouseMet electronic von Frey system. Multicolor flow cytometry was used to determine the effects of CB2R agonists on macrophage activation and T-lymphocyte infiltration into dorsal root ganglia (DRG) and lumbar spinal cord (LSC). Results demonstrated that, following weekly intraperitoneal injections starting at 5 wk p.i., JWH015, JWH133, and Gp1a, but not HU308 (5 mg/kg), significantly ameliorated allodynia when assessed 2 h after ligand injection. However, these same agonists (2x/wk) did not display antiallodynic effects when mechanical sensitivity was assessed 24 h after ligand injection. Infection-induced macrophage activation and T-cell infiltration into the DRG and LSC were observed at 12 wk p.i., but this neuroinflammation was not affected by treatment with any CB2R agonist. Activation of JAK/STAT3 has been shown to contribute to development of neuropathic pain in the LSC and pretreatment of primary murine microglia (2 h) with JWH015-, JWH133-, or Gp1a-blocked IFN-gamma-induced phosphorylation of STAT1 and STAT3. Taken together, these data show that CB2R agonists demonstrate acute, but not long-term, antiallodynic effects on retrovirus infection-induced neuropathic pain.
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9
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Chauhan P, Lokensgard JR. Glial Cell Expression of PD-L1. Int J Mol Sci 2019; 20:ijms20071677. [PMID: 30987269 PMCID: PMC6479336 DOI: 10.3390/ijms20071677] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022] Open
Abstract
The programmed death (PD)-1/PD-L1 pathway is a well-recognized negative immune checkpoint that results in functional inhibition of T-cells. Microglia, the brain-resident immune cells are vital for pathogen detection and initiation of neuroimmune responses. Moreover, microglial cells and astrocytes govern the activity of brain-infiltrating antiviral T-cells through upregulation of PD-L1 expression. While T-cell suppressive responses within brain are undoubtedly beneficial to the host, preventing cytotoxic damage to this vital organ, establishment of a prolonged anti-inflammatory milieu may simultaneously lead to deficiencies in viral clearance. An immune checkpoint blockade targeting the PD-1: PD-L1 (B7-H1; CD274) axis has revolutionized contemporary treatment for a variety of cancers. However, the therapeutic potential of PD1: PD-L1 blockade therapies targeting viral brain reservoirs remains to be determined. For these reasons, it is key to understand both the detrimental and protective functions of this signaling pathway within the brain. This review highlights how glial cells use PD-L1 expression to modulate T-cell effector function and limit detrimental bystander damage, while still retaining an effective defense of the brain.
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Affiliation(s)
- Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
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10
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Liu W, Dai X, Jih J, Chan K, Trang P, Yu X, Balogun R, Mei Y, Liu F, Zhou ZH. Atomic structures and deletion mutant reveal different capsid-binding patterns and functional significance of tegument protein pp150 in murine and human cytomegaloviruses with implications for therapeutic development. PLoS Pathog 2019; 15:e1007615. [PMID: 30779794 PMCID: PMC6396938 DOI: 10.1371/journal.ppat.1007615] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/01/2019] [Accepted: 02/01/2019] [Indexed: 12/12/2022] Open
Abstract
Cytomegalovirus (CMV) infection causes birth defects and life-threatening complications in immunosuppressed patients. Lack of vaccine and need for more effective drugs have driven widespread ongoing therapeutic development efforts against human CMV (HCMV), mostly using murine CMV (MCMV) as the model system for preclinical animal tests. The recent publication (Yu et al., 2017, DOI: 10.1126/science.aam6892) of an atomic model for HCMV capsid with associated tegument protein pp150 has infused impetus for rational design of novel vaccines and drugs, but the absence of high-resolution structural data on MCMV remains a significant knowledge gap in such development efforts. Here, by cryoEM with sub-particle reconstruction method, we have obtained the first atomic structure of MCMV capsid with associated pp150. Surprisingly, the capsid-binding patterns of pp150 differ between HCMV and MCMV despite their highly similar capsid structures. In MCMV, pp150 is absent on triplex Tc and exists as a “Λ”-shaped dimer on other triplexes, leading to only 260 groups of two pp150 subunits per capsid in contrast to 320 groups of three pp150 subunits each in a “Δ”-shaped fortifying configuration. Many more amino acids contribute to pp150-pp150 interactions in MCMV than in HCMV, making MCMV pp150 dimer inflexible thus incompatible to instigate triplex Tc-binding as observed in HCMV. While pp150 is essential in HCMV, our pp150-deletion mutant of MCMV remained viable though with attenuated infectivity and exhibiting defects in retaining viral genome. These results thus invalidate targeting pp150, but lend support to targeting capsid proteins, when using MCMV as a model for HCMV pathogenesis and therapeutic studies. Cytomegalovirus (CMV) infection is a leading viral cause of birth defects and could be deadly to AIDS patients and organ transplant recipients. Absence of effective vaccines and potent drugs against human CMV (HCMV) infections has motivated animal-based studies, mostly based on the mouse model with murine CMV (MCMV), both for understanding pathogenesis of CMV infections and for developing therapeutic strategies. Distinct from other medically important herpesviruses (those responsible for cold sores, genital herpes, shingles and several human cancers), CMV contains an abundant phosphoprotein, pp150, which is a structurally, immunogenically, and regulatorily important tegument protein and a potential drug target. Here, we used cryoEM with localized reconstruction method to obtain the first atomic structure of MCMV. The structure reveals that the organization patterns of the capsid-associated tegument protein pp150 are different in MCMV and HCMV, despite their highly similar capsid structures. We also show that deleting pp150 did not eliminate MCMV infection in contrast to pp150’s essential role in HCMV infections. Our results have significant implication to the current practice of using mouse infected with MCMV for HCMV therapeutic development.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Material Science, East China Normal University, Shanghai, China
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Xinghong Dai
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Jonathan Jih
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Karen Chan
- School of Public Health, University of California at Berkeley, Berkeley, California, United States of America
| | - Phong Trang
- Program in Comparative Biochemistry, University of California at Berkeley, Berkeley, California, United States of America
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, Guangdong, China
| | - Xuekui Yu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Rilwan Balogun
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Ye Mei
- State Key Laboratory of Precision Spectroscopy, School of Physics and Material Science, East China Normal University, Shanghai, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
| | - Fenyong Liu
- School of Public Health, University of California at Berkeley, Berkeley, California, United States of America
- Program in Comparative Biochemistry, University of California at Berkeley, Berkeley, California, United States of America
| | - Z. Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
- * E-mail:
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11
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Clement M, Humphreys IR. Cytokine-Mediated Induction and Regulation of Tissue Damage During Cytomegalovirus Infection. Front Immunol 2019; 10:78. [PMID: 30761144 PMCID: PMC6362858 DOI: 10.3389/fimmu.2019.00078] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/11/2019] [Indexed: 12/25/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a β-herpesvirus with high sero-prevalence within the human population. Primary HCMV infection and life-long carriage are typically asymptomatic. However, HCMV is implicated in exacerbation of chronic conditions and associated damage in individuals with intact immune systems. Furthermore, HCMV is a significant cause of morbidity and mortality in the immunologically immature and immune-compromised where disease is associated with tissue damage. Infection-induced inflammation, including robust cytokine responses, is a key component of pathologies associated with many viruses. Despite encoding a large number of immune-evasion genes, HCMV also triggers the induction of inflammatory cytokine responses during infection. Thus, understanding how cytokines contribute to CMV-induced pathologies and the mechanisms through which they are regulated may inform clinical management of disease. Herein, we discuss our current understanding based on clinical observation and in vivo modeling of disease of the role that cytokines play in CMV pathogenesis. Specifically, in the context of the different tissues and organs in which CMV replicates, we give a broad overview of the beneficial and adverse effects that cytokines have during infection and describe how cytokine-mediated tissue damage is regulated. We discuss the implications of findings derived from mice and humans for therapeutic intervention strategies and our understanding of how host genetics may influence the outcome of CMV infections.
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Affiliation(s)
- Mathew Clement
- Division of Infection and Immunity/Systems Immunity University Research Institute, Cardiff, United Kingdom
| | - Ian R Humphreys
- Division of Infection and Immunity/Systems Immunity University Research Institute, Cardiff, United Kingdom
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12
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Abstract
Activated CD8+ lymphocytes infiltrate the brain in response to many viral infections; where some remain stationed long term as memory T cells. Brain-resident memory T cells (bTRM) are positioned to impart immediate defense against recurrent or reactivated infection. The cytokine and chemokine milieu present within a tissue is critical for TRM generation and retention; and reciprocal interactions exist between brain-resident glia and bTRM. High concentrations of TGF-β are found within brain and this cytokine has been shown to induce CD103 (integrin αeβ7) expression. The majority of T cells persisting within brain express CD103, which aids in retention through interaction with E-cadherin. Likewise, cytokines produced by T cells also modulate microglia. The anti-inflammatory cytokine IL-4 has been shown to preferentially polarize microglial cells toward an M2 phenotype, with a corresponding increase in E-cadherin expression. These findings demonstrate that the brain microenvironment, both during and following inflammation, prominently contributes to the role of CD103 in T cell persistence. Further evidence shows that microglia, and astrocytes, upregulate programmed death (PD) ligand 1 during neuroinflammation, likely to limit neuropathology, and the PD-1: PD-L1 pathway also aids in bTRM generation and retention. Upon reactivation of quiescent neurotropic viruses, bTRM may respond to small amounts of de novo-produced viral antigen by rapidly releasing IFN-γ, resulting in interferon-stimulated gene expression in surrounding glia, thereby amplifying activation of a small number of adaptive immune cells into an organ-wide innate antiviral response. While advantageous from an antiviral perspective; over time, recall response-driven, organ-wide innate immune activation likely has cumulative neurotoxic and neurocognitive consequences.
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Affiliation(s)
- Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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13
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Paul AM, Acharya D, Neupane B, Thompson EA, Gonzalez-Fernandez G, Copeland KM, Garrett M, Liu H, Lopez ME, de Cruz M, Flynt A, Liao J, Guo YL, Gonzalez-Fernandez F, Vig PJS, Bai F. Congenital Zika Virus Infection in Immunocompetent Mice Causes Postnatal Growth Impediment and Neurobehavioral Deficits. Front Microbiol 2018; 9:2028. [PMID: 30210488 PMCID: PMC6124374 DOI: 10.3389/fmicb.2018.02028] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/10/2018] [Indexed: 02/04/2023] Open
Abstract
A small percentage of babies born to Zika virus (ZIKV)-infected mothers manifest severe defects at birth, including microcephaly. Among those who appeared healthy at birth, there are increasing reports of postnatal growth or developmental defects. However, the impact of congenital ZIKV infection in postnatal development is poorly understood. Here, we report that a mild congenital ZIKV-infection in pups born to immunocompetent pregnant mice did not display apparent defects at birth, but manifested postnatal growth impediments and neurobehavioral deficits, which include reduced locomotor and cognitive deficits that persisted into adulthood. We found that the brains of these pups were smaller, had a thinner cortical layer 1, displayed increased astrogliosis, decreased expression of microcephaly- and neuron development- related genes, and increased pathology as compared to mock-infected controls. In summary, our results showed that even a mild congenital ZIKV infection in immunocompetent mice could lead to postnatal deficits, providing definitive experimental evidence for a necessity to closely monitor postnatal growth and development of presumably healthy human infants, whose mothers were exposed to ZIKV infection during pregnancy.
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Affiliation(s)
- Amber M. Paul
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Dhiraj Acharya
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Biswas Neupane
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - E. Ashely Thompson
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | | | | | - Me’Lanae Garrett
- Department of Bioengineering, University of Texas, Arlington, TX, United States
| | - Haibei Liu
- Hattiesburg Clinic, Hattiesburg, MS, United States
| | - Mariper E. Lopez
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Matthew de Cruz
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Alex Flynt
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Jun Liao
- Department of Bioengineering, University of Texas, Arlington, TX, United States
| | - Yan-Lin Guo
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Federico Gonzalez-Fernandez
- Medical Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, MS, United States
- Department of Ophthalmology and Pathology, University of Mississippi Medical Center, Jackson, MS, United States
- Pathrd, Inc.,Jackson, MS, United States
| | - Parminder J. S. Vig
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Fengwei Bai
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
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Ciavarra RP, Machida M, Lundberg PS, Gauronskas P, Wellman LL, Steel C, Aflatooni JO, Sanford LD. Controllable and uncontrollable stress differentially impact pathogenicity and survival in a mouse model of viral encephalitis. J Neuroimmunol 2018; 319:130-141. [PMID: 29580714 DOI: 10.1016/j.jneuroim.2018.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/20/2018] [Accepted: 02/21/2018] [Indexed: 01/08/2023]
Abstract
Intranasal instillation of vesicular stomatitis virus (VSV) into mice given controllable stress (modeled by escapable foot shock, ES) resulted in enhanced pathogenicity and decreased survival relative to infected mice given uncontrollable stress (modeled by inescapable foot shock, IS) and non-shocked control mice. Survival likely reflected differential cytokine gene expression that may have been regulated by miR146a, a predicted stress-responsive upstream regulator. Controllability also enhanced the accumulation of brain T resident memory cells that persisted long after viral clearance. The unexpected facilitatory effect of ES on antiviral neuroimmune responses and pathogenicity may arise from differential immunoactivating and immunosuppressive effects of uncontrollable and controllable stress.
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Affiliation(s)
- Richard P Ciavarra
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, United States; Department of Microbiology and Molecular and Cell Biology, Eastern Virginia Medical School, 700 W Olney Road, Norfolk, VA 23501, United States.
| | - Mayumi Machida
- Sleep Research Laboratory, Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Patric S Lundberg
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Phillip Gauronskas
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Laurie L Wellman
- Sleep Research Laboratory, Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Christina Steel
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Justin O Aflatooni
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501, United States
| | - Larry D Sanford
- Sleep Research Laboratory, Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA 23501, United States
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Voigt V, Andoniou CE, Schuster IS, Oszmiana A, Ong ML, Fleming P, Forrester JV, Degli-Esposti MA. Cytomegalovirus establishes a latent reservoir and triggers long-lasting inflammation in the eye. PLoS Pathog 2018; 14:e1007040. [PMID: 29852019 PMCID: PMC5978784 DOI: 10.1371/journal.ppat.1007040] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/17/2018] [Indexed: 01/15/2023] Open
Abstract
Recent outbreaks of Ebola and Zika have highlighted the possibility that viruses may cause enduring infections in tissues like the eye, including the neural retina, which have been considered immune privileged. Whether this is a peculiarity of exotic viruses remains unclear, since the impact of more common viral infections on neural compartments has not been examined, especially in immunocompetent hosts. Cytomegalovirus is a common, universally distributed pathogen, generally innocuous in healthy individuals. Whether in immunocompetent hosts cytomegalovirus can access the eye, and reside there indefinitely, was unknown. Using the well-established murine cytomegalovirus infection model, we show that systemic infection of immunocompetent hosts results in broad ocular infection, chronic inflammation and establishment of a latent viral pool in the eye. Infection leads to infiltration and accumulation of anti-viral CD8+ T cells in the eye, and to the development of tissue resident memory T cells that localize to the eye, including the retina. These findings identify the eye as an unexpected reservoir for cytomegalovirus, and suggest that common viruses may target this organ more frequently than appreciated. Notably, they also highlight that infection triggers sustained inflammatory responses in the eye, including the neural retina.
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Affiliation(s)
- Valentina Voigt
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Christopher E. Andoniou
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Iona S. Schuster
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Anna Oszmiana
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Monique L. Ong
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Peter Fleming
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - John V. Forrester
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
- University of Aberdeen, Division of Applied Medicine, Section of Immunology and Infection, Institute of Medical Sciences, Foresterhill, Aberdeen, Scotland, United Kingdom
| | - Mariapia A. Degli-Esposti
- Immunology and Virology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
- Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Western Australia, Australia
- * E-mail:
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16
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Prasad S, Hu S, Sheng WS, Chauhan P, Lokensgard JR. Reactive glia promote development of CD103 + CD69 + CD8 + T-cells through programmed cell death-ligand 1 (PD-L1). IMMUNITY INFLAMMATION AND DISEASE 2018; 6:332-344. [PMID: 29602245 PMCID: PMC5946148 DOI: 10.1002/iid3.221] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/21/2018] [Accepted: 03/05/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Previous work from our laboratory has demonstrated in vivo persistence of CD103+ CD69+ brain resident memory CD8+ T-cells (bTRM ) following viral infection, and that the PD-1: PD-L1 pathway promotes development of these TRM cells within the brain. Although glial cells express low basal levels of PD-L1, its expression is upregulated upon IFN-γ-treatment, and they have been shown to modulate antiviral T-cell effector responses through the PD-1: PD-L1 pathway. METHODS We performed flow cytometric analysis of cells from co-cultures of mixed glia and CD8+ T-cells obtained from wild type mice to investigate the role of glial cells in the development of bTRM . RESULTS In this study, we show that interactions between reactive glia and anti-CD3 Ab-stimulated CD8+ T-cells promote development of CD103+ CD69+ CD8+ T-cells through engagement of the PD-1: PD-L1 pathway. These studies used co-cultures of primary murine glial cells obtained from WT animals along with CD8+ T-cells obtained from either WT or PD-1 KO mice. We found that αCD3 Ab-stimulated CD8+ T-cells from WT animals increased expression of CD103 and CD69 when co-cultured with primary murine glial cells. In contrast, significantly reduced expression of CD103 and CD69 was observed using CD8+ T-cells from PD-1 KO mice. We also observed that reactive glia promoted high levels of CD127, a marker of memory precursor effector cells (MPEC), on CD69+ CD8+ T-cells, which promotes development of TRM cells. Interestingly, results obtained using T-cells from PD-1 KO animals showed significantly reduced expression of CD127 on CD69+ CD8+ cells. Additionally, blocking of glial PD-L1 resulted in decreased expression of CD103, along with reduced CD127 on CD69+ CD8+ T-cells. CONCLUSIONS Taken together, these results demonstrate a role for activated glia in promoting development of bTRM through the PD-1: PD-L1 pathway.
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Affiliation(s)
- Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minnesota, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minnesota, USA
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minnesota, USA
| | - Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minnesota, USA
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, Minnesota, USA
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17
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Brizić I, Šušak B, Arapović M, Huszthy PC, Hiršl L, Kveštak D, Juranić Lisnić V, Golemac M, Pernjak Pugel E, Tomac J, Oxenius A, Britt WJ, Arapović J, Krmpotić A, Jonjić S. Brain-resident memory CD8 + T cells induced by congenital CMV infection prevent brain pathology and virus reactivation. Eur J Immunol 2018; 48:950-964. [PMID: 29500823 DOI: 10.1002/eji.201847526] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 01/29/2018] [Accepted: 02/24/2018] [Indexed: 01/03/2023]
Abstract
Congenital HCMV infection is a leading infectious cause of long-term neurodevelopmental sequelae. Infection of newborn mice with mouse cytomegalovirus (MCMV) intraperitoneally is a well-established model of congenital human cytomegalovirus infection, which best recapitulates the hematogenous route of virus spread to brain and subsequent pathology. Here, we used this model to investigate the role, dynamics, and phenotype of CD8+ T cells in the brain following infection of newborn mice. We show that CD8+ T cells infiltrate the brain and form a pool of tissue-resident memory T cells (TRM cells) that persist for lifetime. Adoptively transferred virus-specific CD8+ T cells provide protection against primary MCMV infection in newborn mice, reduce brain pathology, and remain in the brain as TRM cells. Brain CD8+ TRM cells were long-lived, slowly proliferating cells able to respond to local challenge infection. Importantly, brain CD8+ TRM cells controlled latent MCMV and their depletion resulted in virus reactivation and enhanced inflammation in brain.
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Affiliation(s)
- Ilija Brizić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Božo Šušak
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Faculty of Medicine, University of Mostar, Mostar, Bosnia and Herzegovina
| | - Maja Arapović
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Faculty of Medicine, University of Mostar, Mostar, Bosnia and Herzegovina
| | - Peter C Huszthy
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Centre for Immune Regulation, Department of Immunology, University of Oslo, Norway
| | - Lea Hiršl
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Daria Kveštak
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Vanda Juranić Lisnić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Mijo Golemac
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Ester Pernjak Pugel
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jelena Tomac
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | | | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jurica Arapović
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Faculty of Medicine, University of Mostar, Mostar, Bosnia and Herzegovina
| | - Astrid Krmpotić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Chauhan P, Sheng WS, Hu S, Prasad S, Lokensgard JR. Nitrosative damage during retrovirus infection-induced neuropathic pain. J Neuroinflammation 2018; 15:66. [PMID: 29506535 PMCID: PMC5836380 DOI: 10.1186/s12974-018-1107-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/26/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Peripheral neuropathy is currently the most common neurological complication in HIV-infected individuals, occurring in 35-50% of patients undergoing combination anti-retroviral therapy. Data have shown that distal symmetric polyneuropathy develops in mice by 6 weeks following infection with the LP-BM5 retrovirus mixture. Previous work from our laboratory has demonstrated that glial cells modulate antiviral T-cell effector responses through the programmed death (PD)-1: PD-L1 pathway, thereby limiting the deleterious consequences of unrestrained neuroinflammation. METHODS Using the MouseMet electronic von Frey system, we assessed hind-paw mechanical hypersensitivity in LP-BM5-infected wild-type (WT) and PD-1 KO animals. Using multi-color flow cytometry, we quantitatively assessed cellular infiltration and microglial activation. Using real-time RT-PCR, we assessed viral load, expression of IFN-γ, iNOS, and MHC class II. Using western blotting, we measured protein nitrosylation within the lumbar spinal cord (LSC) and dorsal root ganglion (DRG). Histochemical staining was performed to analyze the presence of CD3, ionized calcium binding adaptor molecule (Iba)-1, MHCII, nitrotyrosine, isolectin B4 (IB4) binding, and neurofilament 200 (NF200). Statistical analyses were carried out using graphpad prism. RESULTS Hind-paw mechanical hypersensitivity observed in LP-BM5-infected animals was associated with significantly increased lymphocyte infiltration into the spinal cord and DRG. We also observed elevated expression of IFN-γ (in LSC and DRG) and MHC II (on resident microglia in LSC). We detected elevated levels of 3-nitrotyrosine within the LSC and DRG of LP-BM5-infected animals, an indicator of nitric oxide (NO)-induced protein damage. Moreover, we observed 3-nitrotyrosine in both small (IB4+) and large (NF200+) DRG sensory neurons. Additionally, infected PD-1 KO animals displayed significantly greater mechanical hypersensitivity than WT or uninfected mice at 4 weeks post-infection (p.i.). Accelerated onset of hind-paw hypersensitivity in PD-1 KO animals was associated with significantly increased infiltration of CD4+ and CD8+ T lymphocytes, macrophages, and microglial activation at early time points. Importantly, we also observed elevated levels of 3-nitrotyrosine and iNOS in infected PD-1 KO animals when compared with WT animals. CONCLUSIONS Results reported here connect peripheral immune cell infiltration and reactive gliosis with nitrosative damage. These data may help elucidate how retroviral infection-induced neuroinflammatory networks contribute to nerve damage and neuropathic pain.
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Affiliation(s)
- Priyanka Chauhan
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, 3-107 Microbiology Research Facility, 689 23rd Ave. S.E, Minneapolis, MN 55455 USA
| | - Wen S. Sheng
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, 3-107 Microbiology Research Facility, 689 23rd Ave. S.E, Minneapolis, MN 55455 USA
| | - Shuxian Hu
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, 3-107 Microbiology Research Facility, 689 23rd Ave. S.E, Minneapolis, MN 55455 USA
| | - Sujata Prasad
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, 3-107 Microbiology Research Facility, 689 23rd Ave. S.E, Minneapolis, MN 55455 USA
| | - James R. Lokensgard
- Department of Medicine, Neurovirology Laboratory, University of Minnesota Medical School, 3-107 Microbiology Research Facility, 689 23rd Ave. S.E, Minneapolis, MN 55455 USA
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Korbecki J, Gutowska I, Kojder I, Jeżewski D, Goschorska M, Łukomska A, Lubkowska A, Chlubek D, Baranowska-Bosiacka I. New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection. Oncotarget 2018; 9:7219-7270. [PMID: 29467963 PMCID: PMC5805549 DOI: 10.18632/oncotarget.24102] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 01/02/2018] [Indexed: 11/25/2022] Open
Abstract
Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the 'hallmarks of cancer' in glioblastoma multiforme. Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (Treg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme.
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland.,Department of Biochemistry and Molecular Biology, Faculty of Health Sciences, University of Bielsko-Biała, 43-309 Bielsko-Biała, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland
| | - Ireneusz Kojder
- Department of Applied Neurocognitivistics, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland.,Department of Neurosurgery, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland
| | - Dariusz Jeżewski
- Department of Applied Neurocognitivistics, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland.,Department of Neurosurgery, Pomeranian Medical University in Szczecin, 71-252 Szczecin, Poland
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Agnieszka Łukomska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University in Szczecin, 71-460 Szczecin, Poland
| | - Anna Lubkowska
- Department of Functional Diagnostics and Physical Medicine, Pomeranian Medical University in Szczecin, 71-210 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
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20
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Brizić I, Hiršl L, Britt WJ, Krmpotić A, Jonjić S. Immune responses to congenital cytomegalovirus infection. Microbes Infect 2017; 20:543-551. [PMID: 29287989 DOI: 10.1016/j.micinf.2017.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/15/2017] [Accepted: 12/19/2017] [Indexed: 12/15/2022]
Abstract
Human cytomegalovirus (HCMV) is the most common cause of viral infection acquired in utero. Even though the infection has been studied for several decades, immune determinants important for virus control and mechanisms of long-term sequelae caused by infection are still insufficiently characterized. Animal models of congenital HCMV infection provide unique opportunity to study various aspects of human disease. In this review, we summarize current knowledge on the role of immune system in congenital CMV infection, with emphasis on lessons learned from mouse model of congenital CMV infection.
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Affiliation(s)
- Ilija Brizić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Lea Hiršl
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pediatrics Infectious Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Astrid Krmpotić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia; Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
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Prasad S, Hu S, Sheng WS, Chauhan P, Singh A, Lokensgard JR. The PD-1: PD-L1 pathway promotes development of brain-resident memory T cells following acute viral encephalitis. J Neuroinflammation 2017; 14:82. [PMID: 28407741 PMCID: PMC5390367 DOI: 10.1186/s12974-017-0860-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 04/05/2017] [Indexed: 12/30/2022] Open
Abstract
Background Previous work from our laboratory has demonstrated that during acute viral brain infection, glial cells modulate antiviral T cell effector responses through the PD-1: PD-L1 pathway, thereby limiting the deleterious consequences of unrestrained neuroinflammation. Here, we evaluated the PD-1: PD-L1 pathway in development of brain-resident memory T cells (bTRM) following murine cytomegalovirus (MCMV) infection. Methods Flow cytometric analysis of immune cells was performed at 7, 14, and 30 days post-infection (dpi) to assess the shift of brain-infiltrating CD8+ T cell populations from short-lived effector cells (SLEC) to memory precursor effector cells (MPEC), as well as generation of bTRMs. Results In wild-type (WT) animals, we observed a switch in the phenotype of brain-infiltrating CD8+ T cell populations from KLRG1+ CD127− (SLEC) to KLRG1− CD127+ (MPEC) during transition from acute through chronic phases of infection. At 14 and 30 dpi, the majority of CD8+ T cells expressed CD127, a marker of memory cells. In contrast, fewer CD8+ T cells expressed CD127 within brains of infected, PD-L1 knockout (KO) animals. Notably, in WT mice, a large population of CD8+ T cells was phenotyped as CD103+ CD69+, markers of bTRM, and differences were observed in the numbers of these cells when compared to PD-L1 KOs. Immunohistochemical studies revealed that brain-resident CD103+ bTRM cells were localized to the parenchyma. Higher frequencies of CXCR3 were also observed among WT animals in contrast to PD-L1 KOs. Conclusions Taken together, our results indicate that bTRMs are present within the CNS following viral infection and the PD-1: PD-L1 pathway plays a role in the generation of this brain-resident population. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0860-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sujata Prasad
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA
| | - Shuxian Hu
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA
| | - Wen S Sheng
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA
| | - Priyanka Chauhan
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA
| | - Amar Singh
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA
| | - James R Lokensgard
- Department of Medicine, Neurovirology Laboratory, University of Minnesota, 3-107 Microbiology Research Facility, 689 23rd Avenue S.E., Minneapolis, MN, 55455, USA.
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Chauhan P, Hu S, Sheng WS, Prasad S, Lokensgard JR. Modulation of Microglial Cell Fcγ Receptor Expression Following Viral Brain Infection. Sci Rep 2017; 7:41889. [PMID: 28165503 PMCID: PMC5292951 DOI: 10.1038/srep41889] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/03/2017] [Indexed: 12/22/2022] Open
Abstract
Fcγ receptors (FcγRs) for IgG couple innate and adaptive immunity through activation of effector cells by antigen-antibody complexes. We investigated relative levels of activating and inhibitory FcγRs on brain-resident microglia following murine cytomegalovirus (MCMV) infection. Flow cytometric analysis of microglial cells obtained from infected brain tissue demonstrated that activating FcγRs were expressed maximally at 5 d post-infection (dpi), while the inhibitory receptor (FcγRIIB) remained highly elevated during both acute and chronic phases of infection. The highly induced expression of activating FcγRIV during the acute phase of infection was also noteworthy. Furthermore, in vitro analysis using cultured primary microglia demonstrated the role of interferon (IFN)γ and interleukin (IL)-4 in polarizing these cells towards a M1 or M2 phenotype, respectively. Microglial cell-polarization correlated with maximal expression of either FcγRIV or FcγRIIB following stimulation with IFNγ or IL-4, respectively. Finally, we observed a significant delay in polarization of microglia towards an M2 phenotype in the absence of FcγRs in MCMV-infected Fcer1g and FcgR2b knockout mice. These studies demonstrate that neuro-inflammation following viral infection increases expression of activating FcγRs on M1-polarized microglia. In contrast, expression of the inhibitory FcγRIIB receptor promotes M2-polarization in order to shut-down deleterious immune responses and limit bystander brain damage.
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Affiliation(s)
- Priyanka Chauhan
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Wen S Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Kulkarni A, Scully TJ, O'Donnell LA. The antiviral cytokine interferon-gamma restricts neural stem/progenitor cell proliferation through activation of STAT1 and modulation of retinoblastoma protein phosphorylation. J Neurosci Res 2016; 95:1582-1601. [PMID: 27862183 PMCID: PMC5432422 DOI: 10.1002/jnr.23987] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 09/18/2016] [Accepted: 10/14/2016] [Indexed: 12/20/2022]
Abstract
Neural stem/progenitor cells (NPSCs) express receptors for many inflammatory cytokines, with varying effects on differentiation and proliferation depending on the stage of development and the milieu of inflammatory mediators. In primary neurons and astrocytes, we recently showed that interferon gamma (IFNγ), a potent antiviral cytokine that is required for the control and clearance of many central nervous system (CNS) infections, could differentially affect cell survival and cell cycle progression depending upon the cell type and the profile of activated intracellular signaling molecules. Here, we show that IFNγ inhibits proliferation of primary NSPCs through dephosphorylation of the tumor suppressor Retinoblastoma protein (pRb), which is dependent on activation of signal transducers and activators of transcription‐1 (STAT1) signaling pathways. Our results show i) IFNγ inhibits neurosphere growth and proliferation rate in a dose‐dependent manner; ii) IFNγ blocks cell cycle progression through a late‐stage G1/S phase restriction; iii) IFNγ induces phosphorylation and expression of STAT1 and STAT3; iv) IFNγ decreases cyclin E/cdk2 expression and reduces phosphorylation of cyclin D1 and pRb on serine residue 795; and v) the effects of IFNγ on NSPC proliferation, cell cycle protein expression, and pRb phosphorylation are STAT1‐dependent. These data define a mechanism by which IFNγ could contribute to a reduction in NSPC proliferation in inflammatory conditions. Further delineation of the effects of inflammatory cytokines on NSPC growth could improve our understanding of how CNS infections and other inflammatory events disrupt brain development and NSPC function. © 2016 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Apurva Kulkarni
- Duquesne University, Mylan School of Pharmacy, 600 Forbes Avenue, Pittsburgh, PA, 15282
| | - Taylor J Scully
- Duquesne University, Mylan School of Pharmacy, 600 Forbes Avenue, Pittsburgh, PA, 15282
| | - Lauren A O'Donnell
- Duquesne University, Mylan School of Pharmacy, 600 Forbes Avenue, Pittsburgh, PA, 15282
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Lokensgard JR, Mutnal MB, Prasad S, Sheng W, Hu S. Glial cell activation, recruitment, and survival of B-lineage cells following MCMV brain infection. J Neuroinflammation 2016; 13:114. [PMID: 27207308 PMCID: PMC4874004 DOI: 10.1186/s12974-016-0582-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 05/13/2016] [Indexed: 12/23/2022] Open
Abstract
Background Chemokines produced by reactive glia drive migration of immune cells and previous studies from our laboratory have demonstrated that CD19+ B cells infiltrate the brain. In this study, in vivo and in vitro experiments investigated the role of reactive glial cells in recruitment and survival of B-lineage cells in response to (murine cytomegalovirus) MCMV infection. Methods Flow cytometric analysis was used to assess chemokine receptor expression on brain-infiltrating B cells. Real-time RT-PCR and ELISA were used to measure chemokine levels. Dual-immunohistochemical staining was used to co-localize chemokine production by reactive glia. Primary glial cell cultures and migration assays were used to examine chemokine-mediated recruitment. Astrocyte: B cell co-cultures were used to investigate survival and proliferation. Results The chemokine receptors CXCR3, CXCR5, CCR5, and CCR7 were detected on CD19+ cells isolated from the brain during MCMV infection. In particular, CXCR3 was found to be elevated on an increasing number of cells over the time course of infection, and it was the primary chemokine receptor expressed at 60 days post infection Quite different expression kinetics were observed for CXCR5, CCR5, and CCR7, which were elevated on the highest number of cells early during infection and decreased by 14, 30, and 60 days post infection Correspondingly, elevated levels of CXCL9, CXCL10, and CXCL13, as well as CCL5, were found within the brains of infected animals, and only low levels of CCL3 and CCL19 were detected. Differential expression of CXCL9/CXCL10 and CXCL13 between microglia and astrocytes was apparent, and B cells moved towards supernatants from MCMV-infected microglia, but not astrocytes. Pretreatment with neutralizing Abs to CXCL9 and CXCL10 inhibited this migration. In contrast, neutralizing Abs to the ligand of CXCR5 (i.e., CXCL13) did not significantly block chemotaxis. Proliferation of brain-infiltrating B cells was detected at 7 days post infection and persisted through the latest time tested (60 days post infection). Finally, astrocytes produce BAFF (B cell activating factor of the TNF family) and promote proliferation of B cells via cell-to-cell contact. Conclusions CXCR3 is the primary chemokine receptor on CD19+ B cells persisting within the brain, and migration to microglial cell supernatants is mediated through this receptor. Correspondingly, microglial cells produce CXCL9 and CXCL10, but not CXCL13. Reactive astrocytes promote B cell proliferation.
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Affiliation(s)
- James R Lokensgard
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA.
| | - Manohar B Mutnal
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Sujata Prasad
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Wen Sheng
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
| | - Shuxian Hu
- Neurovirology Laboratory, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN, 55455, USA
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Fantetti KN, Gray EL, Ganesan P, Kulkarni A, O'Donnell LA. Interferon gamma protects neonatal neural stem/progenitor cells during measles virus infection of the brain. J Neuroinflammation 2016; 13:107. [PMID: 27178303 PMCID: PMC4867982 DOI: 10.1186/s12974-016-0571-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 05/06/2016] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND In the developing brain, self-renewing neural stem/progenitor cells (NSPC) give rise to neuronal and glial lineages. NSPC survival and differentiation can be altered by neurotropic viruses and by the anti-viral immune response. Several neurotropic viruses specifically target and infect NSPCs, in addition to inducing neuronal loss, which makes it difficult to distinguish between effects on NSPCs that are due to direct viral infection or due to the anti-viral immune response. METHODS We have investigated the impact of anti-viral immunity on NSPCs in measles virus (MV)-infected neonates. A neuron-restricted viral infection model was used, where NSPCs remain uninfected. Thus, an anti-viral immune response was induced without the confounding issue of NSPC infection. Two-transgenic mouse lines were used: CD46+ mice express the human isoform of CD46, the MV entry receptor, under the control of the neuron-specific enolase promoter; CD46+/IFNγ-KO mice lack the key anti-viral cytokine IFNγ. Multi-color flow cytometry and Western Blot analysis were used to quantify effects on NSPC, neuronal, and glial cell number, and quantify effects on IFNγ-mediated signaling and cell markers, respectively. RESULTS Flow cytometric analysis revealed that NSPCs were reduced in CD46+/IFNγ-KO mice at 3, 7, and 10 days post-infection (dpi), but were unaffected in CD46+ mice. Early neurons showed the greatest cell loss at 7 dpi in both genotypes, with no effect on mature neurons and glial cells. Thus, IFNγ protected against NSPC loss, but did not protect young neurons. Western Blot analyses on hippocampal explants showed reduced nestin expression in the absence of IFNγ, and reduced doublecortin and βIII-tubulin in both genotypes. Phosphorylation of STAT1 and STAT2 occurred independently of IFNγ in the hippocampus, albeit with distinct regulation of activation. CONCLUSIONS This is the first study to demonstrate bystander effects of anti-viral immunity on NSPC function. Our results show IFNγ protects the NSPC population during a neonatal viral CNS infection. Significant loss of NSPCs in CD46+/IFNγ-KO neonates suggests that the adaptive immune response is detrimental to NSPCs in the absence of IFNγ. These results reveal the importance and contribution of the anti-viral immune response to neuropathology and may be relevant to other neuroinflammatory conditions.
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Affiliation(s)
- Kristen N Fantetti
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA, 15282, USA
| | - Erica L Gray
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA, 15282, USA
| | - Priya Ganesan
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA, 15282, USA
| | - Apurva Kulkarni
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA, 15282, USA
| | - Lauren A O'Donnell
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA, 15282, USA.
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Ellwardt E, Walsh JT, Kipnis J, Zipp F. Understanding the Role of T Cells in CNS Homeostasis. Trends Immunol 2016; 37:154-165. [DOI: 10.1016/j.it.2015.12.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 01/16/2023]
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Prasad S, Hu S, Sheng WS, Singh A, Lokensgard JR. Tregs Modulate Lymphocyte Proliferation, Activation, and Resident-Memory T-Cell Accumulation within the Brain during MCMV Infection. PLoS One 2015; 10:e0145457. [PMID: 26720146 PMCID: PMC4697843 DOI: 10.1371/journal.pone.0145457] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/03/2015] [Indexed: 11/25/2022] Open
Abstract
Accumulation and retention of regulatory T-cells (Tregs) has been reported within post viral-encephalitic brains, however, the full extent to which these cells modulate neuroinflammation is yet to be elucidated. Here, we used Foxp3-DTR (diphtheria toxin receptor) knock-in transgenic mice, which upon administration of low dose diphtheria toxin (DTx) results in specific deletion of Tregs. We investigated the proliferation status of various immune cell subtypes within inflamed central nervous system (CNS) tissue. Depletion of Tregs resulted in increased proliferation of both CD8+ and CD4+ T-cell subsets within the brain at 14 d post infection (dpi) when compared to Treg-sufficient animals. At 30 dpi, while proliferation of CD8+ T-cells was controlled within brains of both Treg-depleted and undepleted mice, proliferation of CD4+ T-cells remained significantly enhanced with DTx-treatment. Previous studies have demonstrated that Treg numbers within the brain rebound following DTx treatment to even higher numbers than in untreated animals. Despite this rebound, CD8+ and CD4+ T-cells proliferated at a higher rate when compared to that of Treg-sufficient mice, thus maintaining sustained neuroinflammation. Furthermore, at 30 dpi we found the majority of CD8+ T-cells were CD127hi KLRG1- indicating that the cells were long lived memory precursor cells. These cells showed marked elevation of CD103 expression, a marker of tissue resident-memory T-cells (TRM) in the CNS, in untreated animals when compared to DTx-treated animals suggesting that generation of TRM is impaired upon Treg depletion. Moreover, the effector function of TRM as indicated by granzyme B production in response to peptide re-stimulation was found to be more potent in Treg-sufficient animals. Taken together, our findings demonstrate that Tregs limit neuroinflammatory responses to viral infection by controlling cell proliferation and may direct a larger proportion of lymphocytes within the brain to be maintained as TRM cells.
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Affiliation(s)
- Sujata Prasad
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Shuxian Hu
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Wen S. Sheng
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - Amar Singh
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
| | - James R. Lokensgard
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, 55455, United States of America
- * E-mail:
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Perivascular Arrest of CD8+ T Cells Is a Signature of Experimental Cerebral Malaria. PLoS Pathog 2015; 11:e1005210. [PMID: 26562533 PMCID: PMC4643016 DOI: 10.1371/journal.ppat.1005210] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 09/16/2015] [Indexed: 12/18/2022] Open
Abstract
There is significant evidence that brain-infiltrating CD8+ T cells play a central role in the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the mechanisms through which they mediate their pathogenic activity during malaria infection remain poorly understood. Utilizing intravital two-photon microscopy combined with detailed ex vivo flow cytometric analysis, we show that brain-infiltrating T cells accumulate within the perivascular spaces of brains of mice infected with both ECM-inducing (P. berghei ANKA) and non-inducing (P. berghei NK65) infections. However, perivascular T cells displayed an arrested behavior specifically during P. berghei ANKA infection, despite the brain-accumulating CD8+ T cells exhibiting comparable activation phenotypes during both infections. We observed T cells forming long-term cognate interactions with CX3CR1-bearing antigen presenting cells within the brains during P. berghei ANKA infection, but abrogation of this interaction by targeted depletion of the APC cells failed to prevent ECM development. Pathogenic CD8+ T cells were found to colocalize with rare apoptotic cells expressing CD31, a marker of endothelial cells, within the brain during ECM. However, cellular apoptosis was a rare event and did not result in loss of cerebral vasculature or correspond with the extensive disruption to its integrity observed during ECM. In summary, our data show that the arrest of T cells in the perivascular compartments of the brain is a unique signature of ECM-inducing malaria infection and implies an important role for this event in the development of the ECM-syndrome. Cerebral malaria is the most severe complication of Plasmodium falciparum infection. Utilizing the murine experimental model of cerebral malaria (ECM), it has been found that CD8+ T cells are a key immune cell type responsible for development of cerebral pathology during malaria infection. To identify how CD8+ T cells cause cerebral pathology during malaria infection, in this study we have performed detailed in vivo analysis (two photon imaging) of CD8+ T cells within the brains of mice infected with strains of malaria parasites that cause or do not cause ECM. We found that CD8+ T cells appear to accumulate in similar numbers and in comparable locations within the brains of mice infected with parasites that do or do not cause ECM. Importantly, however, brain accumulating CD8+ T cells displayed significantly different movement characteristics during the different infections. CD8+ T cells interacted with myeloid cells within the brain during infection with parasites causing ECM, but this association was not required for development of cerebral complications. Furthermore, our results suggest that CD8+ T cells do not cause ECM through the widespread killing of brain microvessel cells. The results in this study significantly improve our understanding of the ways through which CD8+ T cells can mediate cerebral pathology during malaria infection.
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Luz A, Fainstein N, Einstein O, Ben-Hur T. The role of CNS TLR2 activation in mediating innate versus adaptive neuroinflammation. Exp Neurol 2015; 273:234-42. [DOI: 10.1016/j.expneurol.2015.08.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 11/24/2022]
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Lokensgard JR, Schachtele SJ, Mutnal MB, Sheng WS, Prasad S, Hu S. Chronic reactive gliosis following regulatory T cell depletion during acute MCMV encephalitis. Glia 2015; 63:1982-1996. [PMID: 26041050 DOI: 10.1002/glia.22868] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/12/2015] [Indexed: 12/21/2022]
Abstract
Long-term, persistent central nervous system inflammation is commonly seen following brain infection. Using a murine model of viral encephalitis (murine cytomegalovirus, MCMV) we have previously shown that post-encephalitic brains are maintained in an inflammatory state consisting of glial cell reactivity, retention of brain-infiltrating tissue-resident memory CD8+ T-cells, and long-term persistence of antibody-producing cells of the B-lineage. Here, we report that this neuroinflammation occurs concomitantly with accumulation and retention of immunosuppressive regulatory T-cells (Tregs), and is exacerbated following their ablation. However, the extent to which these Tregs function to control neuroimmune activation following MCMV encephalitis is unknown. In this study, we used Foxp3-diphtheria toxin receptor-GFP (Foxp3-DTR-GFP) transgenic mice, which upon administration of low-dose diphtheria toxin (DTx) results in the specific depletion of Tregs, to investigate their function. We found treatment with DTx during the acute phase of viral brain infection (0-4 dpi) resulted in depletion of Tregs from the brain, exacerbation of encephalitis (i.e., increased presence of CD4+ and CD8+ T-cells), and chronic reactive phenotypes of resident glial cells (i.e., elevated MHC Class II as well as PD-L1 levels, sustained microgliosis, and increased glial fibrillary acidic protein (GFAP) expression on astrocytes) versus untreated, infected animals. This chronic proinflammatory environment was associated with reduced cognitive performance in spatial learning and memory tasks (Barnes Maze) by convalescent animals. These data demonstrate that chronic glial cell activation, unremitting post-encephalitic neuroinflammation, and its associated long-term neurological sequelae in response to viral brain infection are modulated by the immunoregulatory properties of Tregs. GLIA 2015;63:1982-1996.
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Affiliation(s)
- James R Lokensgard
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Scott J Schachtele
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Manohar B Mutnal
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Wen S Sheng
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Sujata Prasad
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Shuxian Hu
- Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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Mutnal MB, Hu S, Schachtele SJ, Lokensgard JR. Infiltrating regulatory B cells control neuroinflammation following viral brain infection. THE JOURNAL OF IMMUNOLOGY 2014; 193:6070-80. [PMID: 25385825 DOI: 10.4049/jimmunol.1400654] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Previous studies have demonstrated the existence of a subset of B lymphocytes, regulatory B cells (Bregs), which modulate immune function. In this study, in vivo and in vitro experiments were undertaken to elucidate the role of these Bregs in controlling neuroinflammation following viral brain infection. We used multicolor flow cytometry to phenotype lymphocyte subpopulations infiltrating the brain, along with in vitro cocultures to assess their anti-inflammatory and immunoregulatory roles. This distinctive subset of CD19(+)CD1d(hi)CD5(+) B cells was found to infiltrate the brains of chronically infected animals, reaching highest levels at the latest time point tested (30 d postinfection). B cell-deficient Jh(-/-) mice were found to develop exacerbated neuroimmune responses as measured by enhanced accumulation and/or retention of CD8(+) T cells within the brain, as well as increased levels of microglial activation (MHC class II). Conversely, levels of Foxp3(+) regulatory T cells were found to be significantly lower in Jh(-/-) mice when compared with wild-type (Wt) animals. Further experiments showed that in vitro-generated IL-10-secreting Bregs (B10) were able to inhibit cytokine responses from microglia following stimulation with viral Ags. These in vitro-generated B10 cells were also found to promote proliferation of regulatory T cells in coculture studies. Finally, gain-of-function experiments demonstrated that reconstitution of Wt B cells into Jh(-/-) mice restored neuroimmune responses to levels exhibited by infected Wt mice. Taken together, these results demonstrate that Bregs modulate T lymphocyte as well as microglial cell responses within the infected brain and promote CD4(+)Foxp3(+) T cell proliferation in vitro.
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Affiliation(s)
- Manohar B Mutnal
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Shuxian Hu
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Scott J Schachtele
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - James R Lokensgard
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
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Activated CD8+ T lymphocytes inhibit neural stem/progenitor cell proliferation: role of interferon-gamma. PLoS One 2014; 9:e105219. [PMID: 25133679 PMCID: PMC4136865 DOI: 10.1371/journal.pone.0105219] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 07/21/2014] [Indexed: 12/03/2022] Open
Abstract
The ability of neural stem/progenitor cells (NSCs) to self-renew, migrate to damaged sites, and differentiate into neurons has renewed interest in using them in therapies for neurodegenerative disorders. Neurological diseases, including viral infections of the brain, are often accompanied by chronic inflammation, whose impact on NSC function remains unexplored. We have previously shown that chronic neuroinflammation, a hallmark of experimental herpes simplex encephalitis (HSE) in mice, is dominated by brain-infiltrating activated CD8 T-cells. In the present study, activated CD8 lymphocytes were found to suppress NSC proliferation profoundly. Luciferase positive (luc+) NSCs co-cultured with activated, MHC-matched, CD8+ lymphocytes (luc−) showed two- to five-fold lower luminescence than co-cultures with un-stimulated lymphocytes. On the other hand, similarly activated CD4+ lymphocytes did not suppress NSC growth. This differential lymphocyte effect on proliferation was confirmed by decreased BrdU uptake by NSC cultured with activated CD8 T-cells. Interestingly, neutralizing antibodies to interferon-gamma (IFN-γ) reversed the impact of CD8 lymphocytes on NSCs. Antibodies specific to the IFN-γ receptor-1 subunit complex abrogated the inhibitory effects of both CD8 lymphocytes and IFN-γ, indicating that the inhibitory effect of these cells was mediated by IFN-γ in a receptor-specific manner. In addition, activated CD8 lymphocytes decreased levels of nestin and Sox2 expression in NSCs while increasing GFAP expression, suggesting possible induction of an altered differentiation state. Furthermore, NSCs obtained from IFN-γ receptor-1 knock-out embryos were refractory to the inhibitory effects of activated CD8+ T lymphocytes on cell proliferation and Sox2 expression. Taken together, the studies presented here demonstrate a role for activated CD8 T-cells in regulating NSC function mediated through the production of IFN-γ. This cytokine may influence neuro-restorative processes and ultimately contribute to the long-term sequelae commonly seen following herpes encephalitis.
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Slavuljica I, Kveštak D, Huszthy PC, Kosmac K, Britt WJ, Jonjić S. Immunobiology of congenital cytomegalovirus infection of the central nervous system—the murine cytomegalovirus model. Cell Mol Immunol 2014; 12:180-91. [PMID: 25042632 DOI: 10.1038/cmi.2014.51] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 06/02/2014] [Indexed: 02/05/2023] Open
Abstract
Congenital human cytomegalovirus infection is a leading infectious cause of long-term neurodevelopmental sequelae, including mental retardation and hearing defects. Strict species specificity of cytomegaloviruses has restricted the scope of studies of cytomegalovirus infection in animal models. To investigate the pathogenesis of congenital human cytomegalovirus infection, we developed a mouse cytomegalovirus model that recapitulates the major characteristics of central nervous system infection in human infants, including the route of neuroinvasion and neuropathological findings. Following intraperitoneal inoculation of newborn animals with mouse cytomegalovirus, the virus disseminates to the central nervous system during high-level viremia and replicates in the brain parenchyma, resulting in a focal but widespread, non-necrotizing encephalitis. Central nervous system infection is coupled with the recruitment of resident and peripheral immune cells as well as the expression of a large number of pro-inflammatory cytokines. Although infiltration of cellular constituents of the innate immune response characterizes the early immune response in the central nervous system, resolution of productive infection requires virus-specific CD8(+) T cells. Perinatal mouse cytomegalovirus infection results in profoundly altered postnatal development of the mouse central nervous system and long-term motor and sensory disabilities. Based on an enhanced understanding of the pathogenesis of this infection, prospects for novel intervention strategies aimed to improve the outcome of congenital human cytomegalovirus infection are proposed.
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Affiliation(s)
- Irena Slavuljica
- 1] Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia [2] Department of Infectious Diseases, School of Medicine, University of Rijeka, Rijeka, Croatia
| | - Daria Kveštak
- Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia
| | - Peter Csaba Huszthy
- 1] Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia [2] Department of Immunology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kate Kosmac
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stipan Jonjić
- Department of Histology and Embryology, School of Medicine, University of Rijeka, Rijeka, Croatia
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Schachtele SJ, Hu S, Sheng WS, Mutnal MB, Lokensgard JR. Glial cells suppress postencephalitic CD8+ T lymphocytes through PD-L1. Glia 2014; 62:1582-94. [PMID: 24890099 PMCID: PMC4141010 DOI: 10.1002/glia.22701] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 04/30/2014] [Accepted: 05/15/2014] [Indexed: 01/06/2023]
Abstract
Engagement of the programmed death (PD)−1 receptor on activated cells by its ligand (PD‐L1) is a mechanism for suppression of activated T‐lymphocytes. Microglia, the resident inflammatory cells of the brain, are important for pathogen detection and initiation of innate immunity, however, a novel role for these cells as immune regulators has also emerged. PD‐L1 on microglia has been shown to negatively regulate T‐cell activation in models of multiple sclerosis and acute viral encephalitis. In this study, we investigated the role of glial cell PD‐L1 in controlling encephalitogenic CD8+ T‐lymphocytes, which infiltrate the brain to manage viral infection, but remain to produce chronic neuroinflammation. Using a model of chronic neuroinflammation following murine cytomegalovirus (MCMV)‐induced encephalitis, we found that CD8+ T‐cells persisting within the brain expressed PD‐1. Conversely, activated microglia expressed PD‐L1. In vitro, primary murine microglia, which express low basal levels of PD‐L1, upregulated the co‐inhibitory ligand on IFN‐γ‐treatment. Blockade of the PD‐1: PD‐L1 pathway in microglial: CD8+ T‐cell co‐cultures increased T‐cell IFN‐γ and interleukin (IL)−2 production. We observed a similar phenomenon following blockade of this co‐inhibitory pathway in astrocyte: CD8+ T‐cell co‐cultures. Using ex vivo cultures of brain leukocytes, including microglia and CD8+ T‐cells, obtained from mice with MCMV‐induced chronic neuroinflammation, we found that neutralization of either PD‐1 or PD‐L1 increased IFN‐γ production from virus‐specific CD8+ T‐cells stimulated with MCMV IE1168–176 peptide. These data demonstrate that microglia and astrocytes control antiviral T‐cell responses and suggest a therapeutic potential of PD1: PD‐L1 modulation to manage the deleterious consequences of uncontrolled neuroinflammation. GLIA 2014;62:1582–1594 Microglia and astrocytes exert regulatory control over T‐cells during chronic neuroinflammation following viral brain infection. Post-encephalitic glial cells express PD‐L1 and suppress persistent CD8 T‐cells via the PD‐1: PD‐L1 inhibitory pathway.
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Affiliation(s)
- Scott J Schachtele
- Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, McGuire Translational Research Facility, Minneapolis, Minnesota
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Wu T, Hu Y, Lee YT, Bouchard KR, Benechet A, Khanna K, Cauley LS. Lung-resident memory CD8 T cells (TRM) are indispensable for optimal cross-protection against pulmonary virus infection. J Leukoc Biol 2013; 95:215-24. [PMID: 24006506 DOI: 10.1189/jlb.0313180] [Citation(s) in RCA: 398] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Previous studies have shown that some respiratory virus infections leave local populations of tissue TRM cells in the lungs which disappear as heterosubtypic immunity declines. The location of these TRM cells and their contribution to the protective CTL response have not been clearly defined. Here, fluorescence microscopy is used to show that some CD103(+) TRM cells remain embedded in the walls of the large airways long after pulmonary immunization but are absent from systemically primed mice. Viral clearance from the lungs of the locally immunized mice precedes the development of a robust Teff response in the lungs. Whereas large numbers of virus-specific CTLs collect around the bronchial tree during viral clearance, there is little involvement of the remaining lung tissue. Much larger numbers of TEM cells enter the lungs of the systemically immunized animals but do not prevent extensive viral replication or damage to the alveoli. Together, these experiments show that virus-specific antibodies and TRM cells are both required for optimal heterosubtypic immunity, whereas circulating memory CD8 T cells do not substantially alter the course of disease.
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Affiliation(s)
- Tao Wu
- 1.University of Connecticut Health Center, L3062, 263 Farmington Ave., Farmington, CT 06032, USA.
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Establishment of a novel mouse model of ulcerative colitis with concomitant cytomegalovirus infection: in vivo identification of cytomegalovirus persistent infected cells. Inflamm Bowel Dis 2013; 19:1951-63. [PMID: 23839229 DOI: 10.1097/mib.0b013e318293c5bf] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Human cytomegalovirus (HCMV) infection is considered to be an exacerbating factor in patients with ulcerative colitis (UC). However, the pathogenicity of HCMV in the exacerbation of UC remains unclear. The lack of a model mimicking UC with HCMV infection has posed a challenge for research into the pathogenic mechanism of HCMV in flare of UC. Therefore, the aim of our study was to establish a new mouse model of UC with HCMV infection. METHODS We established latent murine CMV (MCMV) infection in T-cell receptor α knockout (TCR-α KO) mice at an early age by adjustment of viral dose. Next, we performed immunohistochemical analysis in various organs of infected adult TCR-α KO mice to prove the correlation between MCMV infection and development of colitis. We then assessed colitis histologically and cytokine expression in the colon of infected and uninfected TCR-α KO mice. Finally, the types of MCMV-infected cells in the inflamed colon were examined by immunohistochemical analysis. RESULTS MCMV antigen-positive cells reappeared predominantly in the inflamed colon of TCR-α KO mice. Severe colitis developed in the infected TCR-α KO mice compared with uninfected mice, and Th1/Th17 and Th2 responses were strongly induced. MCMV-infected cells were mainly perivascular stromal cells including pericytes, expressing platelet-derived growth factor receptor-beta (PDGFR-β) and CXC chemokine ligand 12 (CXCL12). CONCLUSIONS In this study, we established, to our knowledge, the first mouse model of UC with HCMV infection. This model is an excellent tool for clarifying the detailed pathogenicity of HCMV in the exacerbation of UC and developing new treatment strategy for active UC with HCMV infection.
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Mutnal MB, Schachtele SJ, Hu S, Lokensgard JR. T-cell reconstitution during murine acquired immunodeficiency syndrome (MAIDS) produces neuroinflammation and mortality in animals harboring opportunistic viral brain infection. J Neuroinflammation 2013; 10:98. [PMID: 23902750 PMCID: PMC3735417 DOI: 10.1186/1742-2094-10-98] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 07/16/2013] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Highly active antiretroviral therapy (HAART) restores inflammatory immune responses in AIDS patients which may unmask previous subclinical infections or paradoxically exacerbate symptoms of opportunistic infections. In resource-poor settings, 25% of patients receiving HAART may develop CNS-related immune reconstitution inflammatory syndrome (IRIS). Here we describe a reliable mouse model to study underlying immunopathological mechanisms of CNS-IRIS. METHODS Utilizing our HSV brain infection model and mice with MAIDS, we investigated the effect of immune reconstitution on MAIDS mice harboring opportunistic viral brain infection. Using multi-color flow cytometry, we quantitatively measured the cellular infiltrate and microglial activation. RESULTS Infection with the LP-BM5 retroviral mixture was found to confer susceptibility to herpes simplex virus (HSV)-1 brain infection to normally-resistant C57BL/6 mice. Increased susceptibility to brain infection was due to severe immunodeficiency at 8 wks p.i. and a marked increase in programmed death-1 (PD-1) expression on CD4+ and CD8+ T-cells. Both T-cell loss and opportunistic brain infection were associated with high level PD-1 expression because PD-1-knockout mice infected with LP-BM5 did not exhibit lymphopenia and retained resistance to HSV-1. In addition, HSV-infection of MAIDS mice stimulated peripheral immune cell infiltration into the brain and its ensuing microglial activation. Interestingly, while opportunistic herpes virus brain infection of C57BL/6 MAIDS mice was not itself lethal, when T-cell immunity was reconstituted through adoptive transfer of virus-specific CD3+ T-cells, it resulted in significant mortality among recipients. This immune reconstitution-induced mortality was associated with exacerbated neuroinflammation, as determined by MHC class II expression on resident microglia and elevated levels of Th1 cytokines in the brain. CONCLUSIONS Taken together, these results indicate development of an immune reconstitution disease within the central nervous system (CNS-IRD). Experimental immune reconstitution disease of the CNS using T-cell repopulation of lymphopenic murine hosts harboring opportunistic brain infections may help elucidate neuroimmunoregulatory networks that produce CNS-IRIS in patients initiating HAART.
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Affiliation(s)
- Manohar B Mutnal
- Neuroimmunology Laboratory, Center for Infectious Diseases and Microbiology Translational Research, Department of Medicine, University of Minnesota, 3-220 LRB/MTRF, 2001 6th Street S.E., Minneapolis, MN 55455, USA
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Updating the mild encephalitis hypothesis of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2013; 42:71-91. [PMID: 22765923 DOI: 10.1016/j.pnpbp.2012.06.019] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 06/11/2012] [Accepted: 06/25/2012] [Indexed: 12/13/2022]
Abstract
Schizophrenia seems to be a heterogeneous disorder. Emerging evidence indicates that low level neuroinflammation (LLNI) may not occur infrequently. Many infectious agents with low overall pathogenicity are risk factors for psychoses including schizophrenia and for autoimmune disorders. According to the mild encephalitis (ME) hypothesis, LLNI represents the core pathogenetic mechanism in a schizophrenia subgroup that has syndromal overlap with other psychiatric disorders. ME may be triggered by infections, autoimmunity, toxicity, or trauma. A 'late hit' and gene-environment interaction are required to explain major findings about schizophrenia, and both aspects would be consistent with the ME hypothesis. Schizophrenia risk genes stay rather constant within populations despite a resulting low number of progeny; this may result from advantages associated with risk genes, e.g., an improved immune response, which may act protectively within changing environments, although they are associated with the disadvantage of increased susceptibility to psychotic disorders. Specific schizophrenic symptoms may arise with instances of LLNI when certain brain functional systems are involved, in addition to being shaped by pre-existing liability factors. Prodrome phase and the transition to a diseased status may be related to LLNI processes emerging and varying over time. The variability in the course of schizophrenia resembles the varying courses of autoimmune disorders, which result from three required factors: genes, the environment, and the immune system. Preliminary criteria for subgrouping neurodevelopmental, genetic, ME, and other types of schizophrenias are provided. A rare example of ME schizophrenia may be observed in Borna disease virus infection. Neurodevelopmental schizophrenia due to early infections has been estimated by others to explain approximately 30% of cases, but the underlying pathomechanisms of transition to disease remain in question. LLNI (e.g. from reactivation related to persistent infection) may be involved and other pathomechanisms including dysfunction of the blood-brain barrier or the blood-CSF barrier, CNS-endogenous immunity and the volume transmission mode balancing wiring transmission (the latter represented mainly by synaptic transmission, which is often described as being disturbed in schizophrenia). Volume transmission is linked to CSF signaling; and together could represent a common pathogenetic link for the distributed brain dysfunction, dysconnectivity, and brain structural abnormalities observed in schizophrenia. In addition, CSF signaling may extend into peripheral tissues via the CSF outflow pathway along brain nerves and peripheral nerves, and it may explain the peripheral topology of neuronal dysfunctions found, like in olfactory dysfunction, dysautonomia, and even in peripheral tissues, i.e., the muscle lesions that were found in 50% of cases. Modulating factors in schizophrenia, such as stress, hormones, and diet, are also modulating factors in the immune response. Considering recent investigations of CSF, the ME schizophrenia subgroup may constitute approximately 40% of cases.
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Mutnal MB, Hu S, Lokensgard JR. Persistent humoral immune responses in the CNS limit recovery of reactivated murine cytomegalovirus. PLoS One 2012; 7:e33143. [PMID: 22412996 PMCID: PMC3295797 DOI: 10.1371/journal.pone.0033143] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/10/2012] [Indexed: 12/17/2022] Open
Abstract
Background Experimental infection of the mouse brain with murine CMV (MCMV) elicits neuroimmune responses that terminate acute infection while simultaneously preventing extensive bystander damage. Previous studies have determined that CD8+ T lymphocytes are required to restrict acute, productive MCMV infection within the central nervous system (CNS). In this study, we investigated the contribution of humoral immune responses in control of MCMV brain infection. Methodology/Principal Findings Utilizing our MCMV brain infection model, we investigated B-lymphocyte-lineage cells and assessed their role in controlling the recovery of reactivated virus from latently infected brain tissue. Brain infiltrating leukocytes were first phenotyped using markers indicative of B-lymphocytes and plasma cells. Results obtained during these studies showed a steady increase in the recruitment of B-lymphocyte-lineage cells into the brain throughout the time-course of viral infection. Further, MCMV-specific antibody secreting cells (ASC) were detected within the infiltrating leukocyte population using an ELISPOT assay. Immunohistochemical studies of brain sections revealed co-localization of CD138+ cells with either IgG or IgM. Additional immunohistochemical staining for MCMV early antigen 1 (E1, m112–113), a reported marker of viral latency in neurons, confirmed its expression in the brain during latent infection. Finally, using B-cell deficient (Jh−/−) mice we demonstrated that B-lymphocytes control recovery of reactivated virus from latently-infected brain tissue. A significantly higher rate of reactivated virus was recovered from the brains of Jh−/− mice when compared to Wt animals. Conclusion Taken together, these results demonstrate that MCMV infection triggers accumulation and persistence of B-lymphocyte-lineage cells within the brain, which produce antibodies and play a significant role in controlling reactivated virus.
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Affiliation(s)
- Manohar B Mutnal
- Neuroimmunology Laboratory, Department of Medicine, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minnesota, United States of America
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