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Chen S, Yang J, Wei Y, Wei X. Epigenetic regulation of macrophages: from homeostasis maintenance to host defense. Cell Mol Immunol 2019; 17:36-49. [PMID: 31664225 PMCID: PMC6952359 DOI: 10.1038/s41423-019-0315-0] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 09/28/2019] [Indexed: 02/05/2023] Open
Abstract
Macrophages are crucial members of the innate immune response and important regulators. The differentiation and activation of macrophages require the timely regulation of gene expression, which depends on the interaction of a variety of factors, including transcription factors and epigenetic modifications. Epigenetic changes also give macrophages the ability to switch rapidly between cellular programs, indicating the ability of epigenetic mechanisms to affect phenotype plasticity. In this review, we focus on key epigenetic events associated with macrophage fate, highlighting events related to the maintenance of tissue homeostasis, responses to different stimuli and the formation of innate immune memory. Further understanding of the epigenetic regulation of macrophages will be helpful for maintaining tissue integrity, preventing chronic inflammatory diseases and developing therapies to enhance host defense.
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Affiliation(s)
- Siyuan Chen
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, 610041, Chengdu, Sichuan, PR China
| | - Jing Yang
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, 610041, Chengdu, Sichuan, PR China
| | - Yuquan Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, 610041, Chengdu, Sichuan, PR China
| | - Xiawei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, 610041, Chengdu, Sichuan, PR China.
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52
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Salani F, Sterbini V, Sacchinelli E, Garramone M, Bossù P. Is Innate Memory a Double-Edge Sword in Alzheimer's Disease? A Reappraisal of New Concepts and Old Data. Front Immunol 2019; 10:1768. [PMID: 31440234 PMCID: PMC6692769 DOI: 10.3389/fimmu.2019.01768] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/12/2019] [Indexed: 12/16/2022] Open
Abstract
An emergent concept in immunology suggests that innate immune system is capable to undergo non-specific long-term responses and to provide resistance by modifying the reactivity to sequential pathogen challenge. This phenomenon, named innate memory, involves epigenetic, and metabolic reprogramming of innate immune cells. Current literature shows that the innate memory process has a mainly beneficial role in host defense, but sometimes can exert detrimental effects, as common in many diseases. Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and dementia. Accumulating findings demonstrate that inflammation is involved in AD pathogenesis and progression and recent genetic and functional data confirm the driving role of the innate immune component in the disease. Furthermore, AD patients show high burden of the most relevant infectious agents and up-regulation of inflammatory features in their innate immune cells, including an activated, or “primed” status of myeloid phagocytic cells in both brain and periphery, resembling trained immunity conditions. Thus, it is conceivable that AD innate cells may be firstly involved in the attempt to resolve recurrent/persistent inflammation but then acquire a trained phenotype mostly unable to maintain the immune regulation, leaving uncontrolled or sometimes supporting the progression of neurodegeneration. The present review aims to summarize evidence evoking innate immune memory mechanisms in AD, and to interpret their potential role, either protective or harmful, in disease progression. A better understanding of such mechanisms will provide a fertile ground for development of novel diagnostic, and therapeutic pathways in AD cure.
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Affiliation(s)
- Francesca Salani
- Experimental Neuropsychobiology Lab, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Valentina Sterbini
- Experimental Neuropsychobiology Lab, IRCCS Santa Lucia Foundation, Rome, Italy
| | | | | | - Paola Bossù
- Experimental Neuropsychobiology Lab, IRCCS Santa Lucia Foundation, Rome, Italy
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53
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Raijmakers RP, Stenos J, Keijmel SP, Ter Horst R, Novakovic B, Nguyen C, Van Der Meer JW, Netea MG, Bleeker-Rovers CP, Joosten LA, Graves SR. Long-Lasting Transcriptional Changes in Circulating Monocytes of Acute Q Fever Patients. Open Forum Infect Dis 2019; 6:5523799. [PMID: 31363773 PMCID: PMC6667718 DOI: 10.1093/ofid/ofz296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/21/2019] [Indexed: 12/17/2022] Open
Abstract
Objective Although most patients recover from acute Q fever, around 20% develop Q fever fatigue syndrome (QFS), a debilitating fatigue syndrome that lasts at least 6 months. This study investigated transcriptional profiles of circulating monocytes and circulating cytokines as a subsequent mirror of myeloid cell function, 1 and 6 months after an acute Q fever infection. Methods Total RNA of circulating monocytes was collected from 11 acute Q fever patients and 15 healthy controls, matched for age (±5 years) and sex. Samples were collected at a median of 27 days (baseline, interquartile range, 15–35 days) after the infection and again 6 months thereafter. Transcriptome analysis was performed using RNA sequencing. Additionally, concentrations of circulating interleukin (IL)-10, IL-1β, IL-1Ra, and IL-6 were measured in serum. Results At baseline, acute Q fever patients clearly show a differential transcriptional program compared with healthy controls. This is still the case at follow-up, albeit to a lesser extent. At baseline, a significant difference in levels of circulating IL-10 (P = .0019), IL-1β (P = .0067), IL-1Ra (P = .0008), and IL-6 (P = .0003) was seen. At follow-up, this difference had decreased for IL-10 (P = .0136) and IL-1Ra (P = .0017) and had become nonsignificant for IL-1β (P = .1139) and IL-6 (P = .2792). Conclusions We show that an acute Q fever infection has a long-term effect on the transcriptional program of circulating monocytes and, therefore, likely their myeloid progenitor cells, as well as concentrations of circulating IL-10, IL-1β, IL-1Ra, and IL-6.
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Affiliation(s)
- Ruud Ph Raijmakers
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - John Stenos
- Australian Rickettsial Reference Laboratory, University Hospital Geelong
| | - Stephan P Keijmel
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rob Ter Horst
- Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Boris Novakovic
- Faculty of Science, Department of Molecular Biology, Radboud University, Nijmegen, the Netherlands
| | - Chelsea Nguyen
- Australian Rickettsial Reference Laboratory, University Hospital Geelong
| | - Jos Wm Van Der Meer
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mihai G Netea
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Chantal P Bleeker-Rovers
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Leo Ab Joosten
- Radboud Expertise Center for Q Fever.,Department of Internal Medicine, Division of Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands.,Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Stephen R Graves
- Australian Rickettsial Reference Laboratory, University Hospital Geelong
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54
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McCoy KD, Burkhard R, Geuking MB. The microbiome and immune memory formation. Immunol Cell Biol 2019; 97:625-635. [PMID: 31127637 DOI: 10.1111/imcb.12273] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 12/17/2022]
Abstract
The microbiota plays an important role in regulating both the innate and adaptive immune systems. Many studies have focused on the ability of microbes to shape the immune system by stimulating B-cell and antibody responses and the differentiation of T helper cell function. However, an important feature of the immune system is its ability to generate memory responses, which provide increased survival for the host. This review will highlight the role of the microbiota in the induction of immune memory with a focus on both adaptive and innate memory as well as vaccine efficacy.
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Affiliation(s)
- Kathy D McCoy
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Regula Burkhard
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Markus B Geuking
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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55
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Rodriguez RM, Suarez-Alvarez B, Lopez-Larrea C. Therapeutic Epigenetic Reprogramming of Trained Immunity in Myeloid Cells. Trends Immunol 2019; 40:66-80. [PMID: 30595189 DOI: 10.1016/j.it.2018.11.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 10/31/2018] [Accepted: 11/08/2018] [Indexed: 12/20/2022]
Abstract
Infiltrating and tissue-resident myeloid cells are essential regulators of innate and adaptive immunity. During inflammation, and in response to microbial products, these cells can adapt to microenvironmental conditions and acquire specialized functions, including phagocytosis and the production of proinflammatory cytokines. Such myeloid plasticity is driven, in part, by epigenetic dynamics that can sustain stable phenotypes after activation, and which may lead to maladaptive cell polarization states associated with inflammation and autoimmunity. Here, we review recent reports describing epigenetic mechanisms linked to such polarization states and innate immune memory (tolerance and training) in monocyte and macrophage lineages. We discuss how these mechanisms might be targeted to develop putative immunomodulatory tools that might be used to treat a variety of immune-mediated diseases.
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Affiliation(s)
- R M Rodriguez
- Translational Immunology Laboratory, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
| | - B Suarez-Alvarez
- Translational Immunology Laboratory, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.
| | - C Lopez-Larrea
- Translational Immunology Laboratory, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Hospital Universitario Central de Asturias, 33011 Oviedo, Spain; Immunology Department, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.
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56
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Trained Innate Immunity Not Always Amicable. Int J Mol Sci 2019; 20:ijms20102565. [PMID: 31137759 PMCID: PMC6567865 DOI: 10.3390/ijms20102565] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/16/2019] [Accepted: 05/22/2019] [Indexed: 12/14/2022] Open
Abstract
The concept of „trained innate immunity" is understood as the ability of innate immune cells to remember invading agents and to respond nonspecifically to reinfection with increased strength. Trained immunity is orchestrated by epigenetic modifications leading to changes in gene expression and cell physiology. Although this phenomenon was originally seen mainly as a beneficial effect, since it confers broad immunological protection, enhanced immune response of reprogrammed innate immune cells might result in the development or persistence of chronic metabolic, autoimmune or neuroinfalmmatory disorders. This paper overviews several examples where the induction of trained immunity may be essential in the development of diseases characterized by flawed innate immune response.
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57
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Neher JJ, Cunningham C. Priming Microglia for Innate Immune Memory in the Brain. Trends Immunol 2019; 40:358-374. [DOI: 10.1016/j.it.2019.02.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 01/30/2019] [Accepted: 02/01/2019] [Indexed: 01/16/2023]
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58
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Sierra A, Denes A. Editorial for the Special Issue: Microglia-Neuron interactions in health and disease - novel perspectives for translational research. Neuroscience 2019; 405:1-2. [PMID: 30731154 DOI: 10.1016/j.neuroscience.2019.01.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Amanda Sierra
- Achucarro Basque Center for Neuroscience, UPV/EHU Science Park, Barrio Sarriena s/n, Leioa, 48940, Bizkaia, Spain; University of the Basque Country UPV/EHU, Barrio Sarriena s/n, Leioa, 48940, Spain; Ikerbasque Foundation, Maria Diaz de Haro 3, Bilbao, 48013, Bizkaia, Spain.
| | - Adam Denes
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony U. 43, Budapest 1083, Hungary.
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59
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Hamada A, Torre C, Drancourt M, Ghigo E. Trained Immunity Carried by Non-immune Cells. Front Microbiol 2019; 9:3225. [PMID: 30692968 PMCID: PMC6340064 DOI: 10.3389/fmicb.2018.03225] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/11/2018] [Indexed: 12/21/2022] Open
Abstract
“Trained immunity” is a term proposed by Netea to describe the ability of an organism to develop an exacerbated immunological response to protect against a second infection independent of the adaptative immunity. This immunological memory can last from 1 week to several months and is only described in innate immune cells such as monocytes, macrophages, and natural killer cells. Paradoxically, the lifespan of these cells in the blood is shorter than the duration of trained immunity. This observation suggested that trained immunity could be carried by long lifespan cells such as stem cells and non-immune cells like fibroblasts. It is now evident that in addition to performing their putative function in the development and maintenance of tissue homeostasis, non-immune cells also play an important role in the response to pathogens by producing anti-microbial factors, with long-term inflammation suggesting that non-immune cells can be trained to confer long-lasting immunological memory. This review provides a summary of the current relevant knowledge about the cells which possess immunological memory and discusses the possibility that non-immune cells may carry immunological memory and mechanisms that might be involved.
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Affiliation(s)
- Attoumani Hamada
- IRD, MEPHI, Institut Hospitalier Universitaire Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Cédric Torre
- IRD, MEPHI, Institut Hospitalier Universitaire Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Michel Drancourt
- IRD, MEPHI, Institut Hospitalier Universitaire Méditerranée Infection, Aix-Marseille University, Marseille, France
| | - Eric Ghigo
- IRD, MEPHI, Institut Hospitalier Universitaire Méditerranée Infection, Aix-Marseille University, Marseille, France
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60
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McCarthy MM. Sex differences in neuroimmunity as an inherent risk factor. Neuropsychopharmacology 2019; 44:38-44. [PMID: 29977075 PMCID: PMC6235925 DOI: 10.1038/s41386-018-0138-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/01/2018] [Accepted: 06/07/2018] [Indexed: 12/12/2022]
Abstract
Identifying and understanding the sources of inherent risk to neurodevelopmental disorders is a fundamental goal of neuroscience. Being male or being exposed to inflammation early in life are two known risk factors, but they are only infrequently associated with each other. Cellular and molecular mechanisms mediating the masculinization of the brain in animal models reveal a consistent role for inflammatory signaling molecules and immune cells in the healthy male brain. Why this is so remains in the realm of speculation but may have its origins in the maternal immune system. Masculinization of the brain occurs during a restricted critical period that begins in utero and overlaps with the sensitive period during which maternal immune activation negatively impacts the developing brain. The convergence of maleness and early life inflammation as risk factors for neuropsychiatric disorders compels us to consider whether sexual differentiation of the brain in males creates an inherent and greater risk than that experienced by females.
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Affiliation(s)
- Margaret M. McCarthy
- 0000 0001 2175 4264grid.411024.2Department of Pharmacology and Program in Neuroscience, University of Maryland School of Medicine, 655W. Baltimore St., Baltimore, MD 21201 USA
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61
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Trained Innate Immunity and Its Implications for Mucosal Immunity and Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1197:11-26. [PMID: 31732931 DOI: 10.1007/978-3-030-28524-1_2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The long-standing dogma that immunological memory is the exclusive prerogative of the adaptive immune system has been challenged by emerging evidence that innate immunity can also maintain memory of past events. Such immunological imprinting takes two forms, trained innate immunity and tolerance. Trained immunity involves metabolic and epigenetic adaptations in innate immune cells and their progenitors in the bone marrow upon exposure to certain microbial and/or inflammatory stimuli so that the "trained" cells would be poised to respond much faster and stronger to a subsequent challenge (e.g., a new infection that is not necessarily the same as the earlier one). Conversely, tolerance leads to attenuated immune responses to secondary stimuli. This review focuses on trained immunity and discusses evidence for its existence from lower organisms to humans, its mechanistic underpinnings, and its translational ramifications. Although trained immunity can be considered as an evolutionarily conserved beneficial response against reinfections, in the setting of modern societies with high prevalence of chronic mucosal and systemic inflammatory diseases, trained immunity could also promote maladaptive immune responses that aggravate pathology. Thus, depending on context, innate immune memory could be therapeutically manipulated using defined agonists to either promote innate immune responses (particularly useful for the treatment of infections or chemotherapy-induced myelosuppression) or suppress excessive inflammation in inflammatory and autoimmune diseases.
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62
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Abstract
The causes of essential hypertension remain an enigma. Interactions between genetic and external factors are generally recognized to act as aetiological mechanisms that trigger the pathogenesis of high blood pressure. However, the questions of which genes and factors are involved, and when and where such interactions occur, remain unresolved. Emerging evidence indicates that the hypertensive response to pressor stimuli, like many other physiological and behavioural adaptations, can become sensitized to particular stimuli. Studies in animal models show that, similarly to other response systems controlled by the brain, hypertensive response sensitization (HTRS) is mediated by neuroplasticity. The brain circuitry involved in HTRS controls the sympathetic nervous system. This Review outlines evidence supporting the phenomenon of HTRS and describes the range of physiological and psychosocial stressors that can produce a sensitized hypertensive state. Also discussed are the cellular and molecular changes in the brain neural network controlling sympathetic tone involved in long-term storage of information relating to stressors, which could serve to maintain a sensitized state. Finally, this Review concludes with a discussion of why a sensitized hypertensive response might previously have been beneficial and increased biological fitness under some environmental conditions and why today it has become a health-related liability.
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Affiliation(s)
- Alan Kim Johnson
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA.
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA.
- Department of Pharmacology, University of Iowa, Iowa City, IA, USA.
- The François M. Abboud Cardiovascular Center, Iowa City, IA, USA.
| | - Baojian Xue
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
- The François M. Abboud Cardiovascular Center, Iowa City, IA, USA
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63
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64
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Tchessalova D, Posillico CK, Tronson NC. Neuroimmune Activation Drives Multiple Brain States. Front Syst Neurosci 2018; 12:39. [PMID: 30210310 PMCID: PMC6123349 DOI: 10.3389/fnsys.2018.00039] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/07/2018] [Indexed: 12/11/2022] Open
Abstract
Neuroimmune signaling is increasingly identified as a critical component of neuronal processes underlying memory, emotion and cognition. The interactions of microglia and astrocytes with neurons and synapses, and the individual cytokines and immune signaling molecules that mediate these interactions are a current focus of much research. Here, we discuss neuroimmune activation as a mechanism triggering different states that modulate cognitive and affective processes to allow for appropriate behavior during and after illness or injury. We propose that these states lie on a continuum from a naïve homeostatic baseline state in the absence of stimulation, to acute neuroimmune activity and chronic activation. Importantly, consequences of illness or injury including cognitive deficits and mood impairments can persist long after resolution of immune signaling. This suggests that neuroimmune activation also results in an enduring shift in the homeostatic baseline state with long lasting consequences for neural function and behavior. Such different states can be identified in a multidimensional way, using patterns of cytokine and glial activation, behavioral and cognitive changes, and epigenetic signatures. Identifying distinct neuroimmune states and their consequences for neural function will provide a framework for predicting vulnerability to disorders of memory, cognition and emotion both during and long after recovery from illness.
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Affiliation(s)
- Daria Tchessalova
- Neuroscience Graduate Program, School of Medicine, University of Michigan, Ann Arbor, MI, United States
| | | | - Natalie Celia Tronson
- Neuroscience Graduate Program, School of Medicine, University of Michigan, Ann Arbor, MI, United States.,Department of Psychology, University of Michigan, Ann Arbor, MI, United States
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65
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Abstract
Trained immunity was originally proposed as a program of innate immunity memory by innate immunity cells of hematopoietic origin such as the monocytes/macrophages and the NK cells. Here I discuss some old and new data justifying this program and some specific, still unanswered, questions it raises regarding the model fungus Candida albicans and the chronic, inflammatory vulvovaginal disease it causes. Building upon this well-established program, the recent reports that epithelial cells of mammals can also acquire memory from previous stimulations, and the apparent intrinsic ability of many living cells from bacteria to mammals to learn from experience, I suggest an expansion of the concept of trained immunity to include all cells of different lineages with the potential of memorizing previous microbial encounters. This expansion would better fit the complexity of innate immunity and the role it plays in infectious and inflammatory diseases.
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66
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Skaper SD, Facci L, Zusso M, Giusti P. An Inflammation-Centric View of Neurological Disease: Beyond the Neuron. Front Cell Neurosci 2018; 12:72. [PMID: 29618972 PMCID: PMC5871676 DOI: 10.3389/fncel.2018.00072] [Citation(s) in RCA: 321] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
Inflammation is a complex biological response fundamental to how the body deals with injury and infection to eliminate the initial cause of cell injury and effect repair. Unlike a normally beneficial acute inflammatory response, chronic inflammation can lead to tissue damage and ultimately its destruction, and often results from an inappropriate immune response. Inflammation in the nervous system (“neuroinflammation”), especially when prolonged, can be particularly injurious. While inflammation per se may not cause disease, it contributes importantly to disease pathogenesis across both the peripheral (neuropathic pain, fibromyalgia) and central [e.g., Alzheimer disease, Parkinson disease, multiple sclerosis, motor neuron disease, ischemia and traumatic brain injury, depression, and autism spectrum disorder] nervous systems. The existence of extensive lines of communication between the nervous system and immune system represents a fundamental principle underlying neuroinflammation. Immune cell-derived inflammatory molecules are critical for regulation of host responses to inflammation. Although these mediators can originate from various non-neuronal cells, important sources in the above neuropathologies appear to be microglia and mast cells, together with astrocytes and possibly also oligodendrocytes. Understanding neuroinflammation also requires an appreciation that non-neuronal cell—cell interactions, between both glia and mast cells and glia themselves, are an integral part of the inflammation process. Within this context the mast cell occupies a key niche in orchestrating the inflammatory process, from initiation to prolongation. This review will describe the current state of knowledge concerning the biology of neuroinflammation, emphasizing mast cell-glia and glia-glia interactions, then conclude with a consideration of how a cell's endogenous mechanisms might be leveraged to provide a therapeutic strategy to target neuroinflammation.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Laura Facci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
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