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Wyatt-Johnson SK, Kersey HN, Brutkiewicz RR. Enrichment of liver MAIT cells in a mouse model of Alzheimer's disease. J Neuroimmunol 2024; 390:578332. [PMID: 38537322 DOI: 10.1016/j.jneuroim.2024.578332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/14/2024] [Accepted: 03/20/2024] [Indexed: 05/13/2024]
Abstract
Emerging evidence has supported a role for the immune system and liver in Alzheimer's disease (AD). However, our understanding of how hepatic immune cells are altered in AD is limited. We previously found that brain mucosal-associated invariant T (MAIT) cell numbers are increased in AD. Furthermore, loss of MAIT cells and their antigen-presenting molecule, MR1, reduced amyloid-β accumulation in the brain. MAIT cells are also significantly present in the liver. Therefore, we sought to analyze MAIT and other immune cells in the AD liver. Increased frequency of activated MAIT cells (but not conventional T cells) were found in 8-month-old 5XFAD mouse livers. Therefore, these data raise the possibility that there is a role for peripheral MAIT cells in AD pathology.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America.
| | - Holly N Kersey
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States of America.
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Wyatt-Johnson SK, Afify R, Brutkiewicz RR. The immune system in neurological diseases: What innate-like T cells have to say. J Allergy Clin Immunol 2024; 153:913-923. [PMID: 38365015 PMCID: PMC10999338 DOI: 10.1016/j.jaci.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/26/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024]
Abstract
The immune system classically consists of 2 lines of defense, innate and adaptive, both of which interact with one another effectively to protect us against any pathogenic threats. Importantly, there is a diverse subset of cells known as innate-like T cells that act as a bridge between the innate and adaptive immune systems and are pivotal players in eliciting inflammatory immune responses. A growing body of evidence has demonstrated the regulatory impact of these innate-like T cells in central nervous system (CNS) diseases and that such immune cells can traffic into the brain in multiple pathological conditions, which can be typically attributed to the breakdown of the blood-brain barrier. However, until now, it has been poorly understood whether innate-like T cells have direct protective or causative properties, particularly in CNS diseases. Therefore, in this review, our attention is focused on discussing the critical roles of 3 unique subsets of unconventional T cells, namely, natural killer T cells, γδ T cells, and mucosal-associated invariant T cells, in the context of CNS diseases, disorders, and injuries and how the interplay of these immune cells modulates CNS pathology, in an attempt to gain a better understanding of their complex functions.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Microbiology and Immunology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Ind
| | - Reham Afify
- Department of Microbiology and Immunology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Ind
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Ind.
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Shrinivasan R, Wyatt-Johnson SK, Brutkiewicz RR. The MR1/MAIT cell axis in CNS diseases. Brain Behav Immun 2024; 116:321-328. [PMID: 38157945 PMCID: PMC10842441 DOI: 10.1016/j.bbi.2023.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 12/14/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024] Open
Abstract
Mucosal-associated invariant T (MAIT) cells are a subpopulation of innate-like T cells that can be found throughout the body, predominantly in mucosal sites, the lungs and in the peripheral blood. MAIT cells recognize microbial-derived vitamin B (e.g., riboflavin) metabolite antigens that are presented by the major histocompatibility complex class I-like protein, MR1, found on a variety of cell types in the periphery and the CNS. Since their original discovery, MAIT cells have been studied predominantly in their roles in diseases in the periphery; however, it was not until the early 2000s that these cells were first examined for their contributions to disorders of the CNS, with the bulk of the work being done within the past few years. Currently, the MR1/MAIT cell axis has been investigated in only a few neurological diseases including, multiple sclerosis and experimental autoimmune encephalomyelitis, brain cancer/tumors, ischemia, cerebral palsy, general aging and, most recently, Alzheimer's disease. Each of these diseases demonstrates a role for this under-studied innate immune axis in its neuropathology. Together, they highlight the importance of studying the MR1/MAIT cell axis in CNS disorders. Here, we review the contributions of the MR1/MAIT cell axis in the progression or remission of these neurological diseases. This work has shed some light in terms of potentially exploiting the MR1/MAIT cell axis in novel therapeutic applications.
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Affiliation(s)
- Rashmi Shrinivasan
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Season K Wyatt-Johnson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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Wyatt-Johnson SK, Kersey HN, Codocedo JF, Newell KL, Landreth GE, Lamb BT, Oblak AL, Brutkiewicz RR. Control of the temporal development of Alzheimer's disease pathology by the MR1/MAIT cell axis. J Neuroinflammation 2023; 20:78. [PMID: 36944969 PMCID: PMC10029194 DOI: 10.1186/s12974-023-02761-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/10/2023] [Indexed: 03/23/2023] Open
Abstract
BACKGROUND Neuroinflammation is an important feature of Alzheimer's disease (AD). Understanding which aspects of the immune system are important in AD may lead to new therapeutic approaches. We study the major histocompatibility complex class I-related immune molecule, MR1, which is recognized by an innate-like T cell population called mucosal-associated invariant T (MAIT) cells. METHODS Having found that MR1 gene expression is elevated in the brain tissue of AD patients by mining the Agora database, we sought to examine the role of the MR1/MAIT cell axis in AD pathology. Brain tissue from AD patients and the 5XFAD mouse model of AD were used to analyze MR1 expression through qPCR, immunofluorescence, and flow cytometry. Furthermore, mice deficient in MR1 and MAIT cells were crossed with the 5XFAD mice to produce a model to study how the loss of this innate immune axis alters AD progression. Moreover, 5XFAD mice were also used to study brain-resident MAIT cells over time. RESULTS In tissue samples from AD patients and 5XFAD mice, MR1 expression was substantially elevated in the microglia surrounding plaques vs. those that are further away (human AD: P < 0.05; 5XFAD: P < 0.001). In 5XFAD mice lacking the MR1/MAIT cell axis, the development of amyloid-beta plaque pathology occurred at a significantly slower rate than in those mice with MR1 and MAIT cells. Furthermore, in brain tissue from 5XFAD mice, there was a temporal increase in MAIT cell numbers (P < 0.01) and their activation state, the latter determined by detecting an upregulation of both CD69 (P < 0.05) and the interleukin-2 receptor alpha chain (P < 0.05) via flow cytometry. CONCLUSIONS Together, these data reveal a previously unknown role for the MR1/MAIT cell innate immune axis in AD pathology and its potential utility as a novel therapeutic target.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Holly N Kersey
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Juan F Codocedo
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Kathy L Newell
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gary E Landreth
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Adrian L Oblak
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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Wyatt-Johnson SK, Sommer AL, Shim KY, Brewster AL. Suppression of Microgliosis With the Colony-Stimulating Factor 1 Receptor Inhibitor PLX3397 Does Not Attenuate Memory Defects During Epileptogenesis in the Rat. Front Neurol 2021; 12:651096. [PMID: 34149593 PMCID: PMC8209304 DOI: 10.3389/fneur.2021.651096] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/11/2021] [Indexed: 12/03/2022] Open
Abstract
Events of status epilepticus (SE) trigger the development of temporal lobe epilepsy (TLE), a type of focal epilepsy that is commonly drug-resistant and is highly comorbid with cognitive deficits. While SE-induced hippocampal injury, accompanied by gliosis and neuronal loss, typically disrupts cognitive functions resulting in memory defects, it is not definitively known how. Our previous studies revealed extensive hippocampal microgliosis that peaked between 2 and 3 weeks after SE and paralleled the development of cognitive impairments, suggesting a role for reactive microglia in this pathophysiology. Microglial survival and proliferation are regulated by the colony-stimulating factor 1 receptor (CSF1R). The CSF1R inhibitor PLX3397 has been shown to reduce/deplete microglial populations and improve cognitive performance in models of neurodegenerative disorders. Therefore, we hypothesized that suppression of microgliosis with PLX3397 during epileptogenesis may attenuate the hippocampal-dependent spatial learning and memory deficits in the rat pilocarpine model of SE and acquired TLE. Different groups of control and SE rats were fed standard chow (SC) or chow with PLX3397 starting immediately after SE and for 3 weeks. Novel object recognition (NOR) and Barnes maze (BM) were performed to determine memory function between 2 and 3 weeks after SE. Then microglial populations were assessed using immunohistochemistry. Control rats fed with either SC or PLX3397 performed similarly in both NOR and BM tests, differentiating novel vs. familiar objects in NOR, and rapidly learning the location of the hidden platform in BM. In contrast, both SE groups (SC and PLX3397) showed significant deficits in both NOR and BM tests compared to controls. Both PLX3397-treated control and SE groups had significantly decreased numbers of microglia in the hippocampus (60%) compared to those in SC. In parallel, we found that PLX3397 treatment also reduced SE-induced hippocampal astrogliosis. Thus, despite drastic reductions in microglial cells, memory was unaffected in the PLX3397-treated groups compared to those in SC, suggesting that remaining microglia may be sufficient to help maintain hippocampal functions. In sum, PLX3397 did not improve or worsen the memory deficits in rats that sustained pilocarpine-induced SE. Further research is required to determine whether microglia play a role in cognitive decline during epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Alexandra L Sommer
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Kevin Y Shim
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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Wyatt-Johnson SK, Brutkiewicz RR. The Complexity of Microglial Interactions With Innate and Adaptive Immune Cells in Alzheimer's Disease. Front Aging Neurosci 2020; 12:592359. [PMID: 33328972 PMCID: PMC7718034 DOI: 10.3389/fnagi.2020.592359] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/20/2020] [Indexed: 12/19/2022] Open
Abstract
In the naïve mouse brain, microglia and astrocytes are the most abundant immune cells; however, there is a complexity of other immune cells present including monocytes, neutrophils, and lymphocytic cells, such as natural killer (NK) cells, T cells, and B cells. In Alzheimer’s disease (AD), there is high inflammation, reactive microglia, and astrocytes, leaky blood–brain barrier, the buildup of amyloid-beta (Aβ) plaques, and neurofibrillary tangles which attract infiltrating peripheral immune cells that are interacting with the resident microglia. Limited studies have analyzed how these infiltrating immune cells contribute to the neuropathology of AD and even fewer have analyzed their interactions with the resident microglia. Understanding the complexity and dynamics of how these immune cells interact in AD will be important for identifying new and novel therapeutic targets. Thus, this review will focus on discussing our current understanding of how macrophages, neutrophils, NK cells, T cells, and B cells, alongside astrocytes, are altered in AD and what this means for the disorder, as well as how these cells are affected relative to the resident microglia.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Microbiology and Immunology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Randy R Brutkiewicz
- Department of Microbiology and Immunology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
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Abstract
Microglia are the resident immune cells and professional phagocytes of the central nervous system. However, little is known about the contribution of their phagocytic signaling to the neuropathology and pathophysiology of epilepsy. Here, we summarize and discuss the implications of recent evidence supporting that aberrant microglia phagocytic activity and alterations in phagocytosis signaling molecules occur in association with microglia-neuronal contacts, neuronal/synaptic loss, and spontaneous recurrent seizures in human and preclinical models of epilepsy. This body of evidence provides strong support that the microglial contribution to epileptogenic networks goes beyond inflammation, and suggests that phagocytic signaling molecules may be novel therapeutic targets for epilepsy.
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Affiliation(s)
| | - Amy L. Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
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Wyatt-Johnson SK, Herr SA, Brewster AL. Status Epilepticus Triggers Time-Dependent Alterations in Microglia Abundance and Morphological Phenotypes in the Hippocampus. Front Neurol 2017; 8:700. [PMID: 29326654 PMCID: PMC5741821 DOI: 10.3389/fneur.2017.00700] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/06/2017] [Indexed: 12/30/2022] Open
Abstract
Status epilepticus (SE) is defined by the occurrence of prolonged “non-stop” seizures that last for at least 5 min. SE provokes inflammatory responses including the activation of microglial cells, the brain’s resident immune cells, which are thought to contribute to the neuropathology and pathophysiology of epilepsy. Microglia are professional phagocytes that resemble peripheral macrophages. Upon sensing immune disturbances, including SE, microglia become reactive, produce inflammatory cytokines, and alter their actin cytoskeleton to transform from ramified to amoeboid shapes. It is widely known that SE triggers time-dependent microglial expression of pro-inflammatory cytokines that include TNFα and IL-1β. However, less is known in regards to the spatiotemporal progression of the morphological changes, which may help define the extent of microglia reactivity after SE and potential function (surveillance, inflammatory, phagocytic). Therefore, in this study, we used the microglia/macrophage IBA1 marker to identify and count these cells in hippocampi from control rats and at 4 h, 3 days, and 2 weeks after a single episode of pilocarpine-induced SE. We identified, categorized, and counted the IBA1-positive cells with the different morphologies observed after SE in the hippocampal areas CA1, CA3, and dentate gyrus. These included ramified, hypertrophic, bushy, amoeboid, and rod. We found that the ramified phenotype was the most abundant in control hippocampi. In contrast, SE provoked time-dependent changes in the microglial morphology that was characterized by significant increases in the abundance of bushy-shaped cells at 4 h and amoeboid-shaped cells at 3 days and 2 weeks. Interestingly, a significant increase in the number of rod-shaped cells was only evident in the CA1 region at 2 weeks after SE. Taken together, these data suggest that SE triggers time-dependent alterations in the morphology of microglial cells. This detailed description of the spatiotemporal profile of SE-induced microglial morphological changes may help provide insight into their contribution to epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States
| | - Seth A Herr
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, West Lafayette, IN, United States
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