scholarly journals Involvement of Microglia in the Pathophysiology of Intracranial Aneurysms and Vascular Malformations—A Short Overview

2021 ◽  
Vol 22 (11) ◽  
pp. 6141
Author(s):  
Teodora Larisa Timis ◽  
Ioan Alexandru Florian ◽  
Sergiu Susman ◽  
Ioan Stefan Florian
Keyword(s):  
Immune Cells ◽  
Arteriovenous Malformations ◽  
Intracranial Aneurysms ◽  
Immune Cell ◽  
Vascular Malformations ◽  
Cerebral Injury ◽  
Future Research ◽  
Mortality And Morbidity ◽  
The Central Nervous System ◽  
The Brain

Aneurysms and vascular malformations of the brain represent an important source of intracranial hemorrhage and subsequent mortality and morbidity. We are only beginning to discern the involvement of microglia, the resident immune cell of the central nervous system, in these pathologies and their outcomes. Recent evidence suggests that activated proinflammatory microglia are implicated in the expansion of brain injury following subarachnoid hemorrhage (SAH) in both the acute and chronic phases, being also a main actor in vasospasm, considerably the most severe complication of SAH. On the other hand, anti-inflammatory microglia may be involved in the resolution of cerebral injury and hemorrhage. These immune cells have also been observed in high numbers in brain arteriovenous malformations (bAVM) and cerebral cavernomas (CCM), although their roles in these lesions are currently incompletely ascertained. The following review aims to shed a light on the most significant findings related to microglia and their roles in intracranial aneurysms and vascular malformations, as well as possibly establish the course for future research.

scholarly journals A Dynamic in vitro BBB Model for the Study of Immune Cell Trafficking into the Central Nervous System

2010 ◽  
Vol 31 (2) ◽  
pp. 767-777 ◽  
Author(s):  
Luca Cucullo ◽  
Nicola Marchi ◽  
Mohammed Hossain ◽  
Damir Janigro
Keyword(s):  
Immune Cells ◽  
Immune Cell ◽  
Cell Trafficking ◽  
In Vitro System ◽  
Immune Cell Trafficking ◽  
The Central Nervous System ◽  
In Vitro Bbb Model ◽  
The Brain

Although there is significant evidence correlating overreacting or perhaps misguided immune cells and the blood–brain barrier (BBB) with the pathogenesis of neuroinflammatory diseases, the mechanisms by which they enter the brain are largely unknown. For this purpose, we revised our humanized dynamic in vitro BBB model (DIV-BBBr) to incorporate modified hollow fibers that now feature transmural microholes (2 to 4 μm Ø) allowing for the transendothelial trafficking of immune cells. As with the original model, this new DIV-BBBr reproduces most of the physiological characteristics of the BBB in vivo. Measurements of transendothelial electrical resistance (TEER), sucrose permeability, and BBB integrity during reversible osmotic disruption with mannitol (1.6 mol/L) showed that the microholes do not hamper the formation of a tight functional barrier. The in vivo rank permeability order of sucrose, phenytoin, and diazepam was successfully reproduced in vitro. Flow cessation followed by reperfusion (Fc/Rp) in the presence of circulating monocytes caused a biphasic BBB opening paralleled by a significant increase of proinflammatory cytokines and activated matrix metalloproteinases. We also observed abluminal extravasation of monocytes but only when the BBB was breached. In conclusion, the DIV-BBBr represents the most realistic in vitro system to study the immune cell trafficking across the BBB.

scholarly journals Immune cell-specific Cre reporter mouse labels a subset of CNS neurons

2019 ◽  
Author(s):  
Aurélie Bouteau ◽  
Botond Z. Igyártó
Keyword(s):  
Immune Cells ◽  
Langerhans Cells ◽  
Immune Cell ◽  
Neuronal Marker ◽  
Reporter Mouse ◽  
Cns Neurons ◽  
The Central Nervous System ◽  
Antigen Presenting

AbstractHuLangerin-Cre-YFPf/f mice were generated to specifically mark a subset of antigen presenting immune cells, called Langerhans cells (LCs). During histological characterization of these mice, we found that, in addition to LCs an uncharacterized cell population in the central nervous system (CNS) also expressed YFP. In this study, we found that the CNS YFP+ cells were negative for microglia and astrocyte markers, but they expressed mature neuronal marker NeuN and showed neuronal localization/morphology. Thus, these mice might be used to study the ontogeny, migration and the role of a subset of CNS neurons.

scholarly journals Pharmacologic Depletion of Microglia Increases Viral Load in the Brain and Enhances Mortality in Murine Models of Flavivirus-Induced Encephalitis

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Scott Seitz ◽  
Penny Clarke ◽  
Kenneth L. Tyler
Keyword(s):  
Immune Cells ◽  
Mrna Level ◽  
Cns Injury ◽  
Cytokines And Chemokines ◽  
Life Threatening ◽  
The Central Nervous System ◽  
The Brain ◽  
Stimulating Factor ◽  
Life Threatening Event

ABSTRACT Flaviviruses account for most arthropod-borne cases of human encephalitis in the world. However, the exact mechanisms of injury to the central nervous system (CNS) during flavivirus infections remain poorly understood. Microglia are the resident immune cells of the CNS and are important for multiple functions, including control of viral pathogenesis. Utilizing a pharmacologic method of microglia depletion (PLX5622 [Plexxikon Inc.], an inhibitor of colony-stimulating factor 1 receptor), we sought to determine the role of microglia in flaviviral pathogenesis. Depletion of microglia resulted in increased mortality and viral titer in the brain following infection with either West Nile virus (WNV) or Japanese encephalitis virus (JEV). Interestingly, microglial depletion did not prevent virus-induced increases in the expression of relevant cytokines and chemokines at the mRNA level. In fact, the expression of several proinflammatory genes was increased in virus-infected, microglia-depleted mice compared to virus-infected, untreated controls. In contrast, and as expected, expression of the macrophage marker triggering receptor expressed on myeloid cells 2 (TREM2) was decreased in virus-infected, PLX5622-treated mice compared to virus-infected controls. IMPORTANCE As CNS invasion by flaviviruses is a rare but life-threatening event, it is critical to understand how brain-resident immune cells elicit protection or injury during disease progression. Microglia have been shown to be important in viral clearance but may also contribute to CNS injury as part of the neuroinflammatory process. By utilizing a microglial depletion model, we can begin to parse out the exact roles of microglia during flaviviral pathogenesis with hopes of understanding specific mechanisms as potential targets for therapeutics.

scholarly journals Immune cells and CNS physiology: Microglia and beyond

2018 ◽  
Vol 216 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Geoffrey T. Norris ◽  
Jonathan Kipnis
Keyword(s):  
Central Nervous System ◽  
Immune Cells ◽  
Brain Function ◽  
Brain Parenchyma ◽  
The Body ◽  
Immune Repertoire ◽  
Perivascular Macrophages ◽  
The Central Nervous System ◽  
Cns Immunity ◽  
The Brain

Recent advances have directed our knowledge of the immune system from a narrative of “self” versus “nonself” to one in which immune function is critical for homeostasis of organs throughout the body. This is also the case with respect to the central nervous system (CNS). CNS immunity exists in a segregated state, with a marked partition occurring between the brain parenchyma and meningeal spaces. While the brain parenchyma is patrolled by perivascular macrophages and microglia, the meningeal spaces are supplied with a diverse immune repertoire. In this review, we posit that such partition allows for neuro–immune crosstalk to be properly tuned. Convention may imply that meningeal immunity is an ominous threat to brain function; however, recent studies have shown that its presence may instead be a steady hand directing the CNS to optimal performance.

Intracranial Aneurysms and Vascular Malformations: Diagnosis for Therapy

2011 ◽  
Vol 24 (6) ◽  
pp. 889-894 ◽  
Author(s):  
M. Grobovschek ◽  
M. Himmer ◽  
P. Wolfsgruber ◽  
F. Weymayr
Keyword(s):  
Arteriovenous Malformations ◽  
Intracranial Aneurysms ◽  
Vascular Malformations ◽  
Future Trends ◽  
Interventional Techniques ◽  
The Future

In the second part of our overviewstudy the diagnosis for the treatment of our patients with intracranial vascular malformations (aneurysms / AVMF– arteriovenous malformations) is again shown in a region of about 500.000 inhabitants and just an overview of the outcome. This second part will be an overall comparison between the former diagnostic for the treatment and the here described diagnostic for the treatment (CTA, MRA, DSA rot / microsurgery, endovascular interventional techniques etc.), concerning also the topography and the demography. The future trends are also outlined.

scholarly journals Evaluation of genetic risk loci for intracranial aneurysms in sporadic arteriovenous malformations of the brain

2014 ◽  
Vol 86 (5) ◽  
pp. 524-529 ◽  
Author(s):  
P H C Kremer ◽  
B P C Koeleman ◽  
L Pawlikowska ◽  
S Weinsheimer ◽  
N Bendjilali ◽  
...  
Keyword(s):  
Genetic Risk ◽  
Arteriovenous Malformations ◽  
Intracranial Aneurysms ◽  
The Brain

scholarly journals Regulated Release of Cryptococcal Polysaccharide Drives Virulence and Suppresses Immune Cell Infiltration into the Central Nervous System

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Steven T. Denham ◽  
Surbhi Verma ◽  
Raymond C. Reynolds ◽  
Colleen L. Worne ◽  
Joshua M. Daugherty ◽  
...  
Keyword(s):  
Cell Size ◽  
Immune Cell ◽  
Opportunistic Pathogen ◽  
Cell Infiltration ◽  
Immune Cell Infiltration ◽  
Content Type ◽  
The Central Nervous System ◽  
Capsule Thickness ◽  
The Brain

ABSTRACTCryptococcus neoformansis a common environmental yeast and opportunistic pathogen responsible for 15% of AIDS-related deaths worldwide. Mortality primarily results from meningoencephalitis, which occurs when fungal cells disseminate to the brain from the initial pulmonary infection site. A keyC. neoformansvirulence trait is the polysaccharide capsule. Capsule shieldsC. neoformansfrom immune-mediated recognition and destruction. The main capsule component, glucuronoxylomannan (GXM), is found both attached to the cell surface and free in the extracellular space (as exo-GXM). Exo-GXM accumulates in patient serum and cerebrospinal fluid at microgram/milliliter concentrations, has well-documented immunosuppressive properties, and correlates with poor patient outcomes. However, it is poorly understood whether exo-GXM release is regulated or the result of shedding during normal capsule turnover. We demonstrate that exo-GXM release is regulated by environmental cues and inversely correlates with surface capsule levels. We identified genes specifically involved in exo-GXM release that do not alter surface capsule thickness. The first mutant, theliv7Δ strain, released less GXM than wild-type cells when capsule was not induced. The second mutant, thecnag_00658Δ strain, released more exo-GXM under capsule-inducing conditions. Exo-GXM release observedin vitrocorrelated with polystyrene adherence, virulence, and fungal burden during murine infection. Additionally, we found that exo-GXM reduced cell size and capsule thickness under capsule-inducing conditions, potentially influencing dissemination. Finally, we demonstrated that exo-GXM prevents immune cell infiltration into the brain during disseminated infection and highly inflammatory intracranial infection. Our data suggest that exo-GXM performs a distinct role from capsule GXM during infection, altering cell size and suppressing inflammation.

scholarly journals Multi-modal single cell analysis reveals brain immune landscape plasticity during aging and gut microbiota dysbiosis

2020 ◽  
Author(s):  
Samantha M. Golomb ◽  
Ian H. Guldner ◽  
Anqi Zhao ◽  
Qingfei Wang ◽  
Bhavana Palakurthi ◽  
...  
Keyword(s):  
Single Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Cell Types ◽  
Cell Plasticity ◽  
Tissue Microenvironment ◽  
Gut Dysbiosis ◽  
Resolution Single ◽  
The Brain ◽  
Gut Microbiota Dysbiosis

ABSTRACTThe brain contains a diverse array of immune cell types. The phenotypic and functional plasticity of brain immune cells collectively contribute to brain tissue homeostasis and disease progression. Immune cell plasticity is profoundly influenced by local tissue microenvironment cues and systemic factors. Yet, the transcriptional mechanism by which systemic stimuli, such as aging and gut microbiota dysbiosis, reshape brain immune cell plasticity and homeostasis has not been fully delineated. Using Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq), we analyzed compositional and transcriptional changes of the brain immune landscape in response to aging and gut dysbiosis. We first examined the discordance between canonical surface marker-defined immune cell types (Cell-ID) and their transcriptome signatures, which suggested transcriptional plasticity among immune cells despite sharing the same cell surface markers. Specifically, inflammatory and patrolling Ly6C+ monocytes were shifted predominantly to a pro-inflammatory transcriptional program in the aged brain, while brain ILCs shifted toward an ILC2 transcriptional profile. Finally, aging led to an increase of ILC-like cells expressing a T memory stemness (Tscm) signature in the brain. Antibiotics (ABX)-induced gut dysbiosis reduced the frequency of ILCs exhibiting Tscm-like properties in the aged mice, but not in the young mice. Enabled by high-resolution single-cell molecular phenotyping, our study revealed that systemic changes due to aging and gut dysbiosis prime the brain environment for an increased propensity for neuroinflammation, which provided insights into gut dysbiosis in age-related neurological diseases.Manuscript SummaryGolomb et al. performed Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) on immune cells from the brains of young and aged mice with and without antibiotics-induced gut dysbiosis. High resolution, single cell immunophenotyping enabled the dissection of extensive transcriptional plasticity of canonically identified monocytes and innate lymphoid cells (ILCs) in the aged brain. Through differential gene expression and trajectory inference analyses, the authors revealed tissue microenvironment-dependent cellular responses influenced by aging and gut dysbiosis that may potentiate neuroinflammatory diseases.Graphical Abstract

scholarly journals Dysregulation of Systemic Immunity in Aging and Dementia

2021 ◽  
Vol 15 ◽  
Author(s):  
Jenny Lutshumba ◽  
Barbara S. Nikolajczyk ◽  
Adam D. Bachstetter
Keyword(s):  
Immune System ◽  
Immune Cells ◽  
Cell Function ◽  
Immune Cell ◽  
Human Subjects ◽  
Brain Inflammation ◽  
Adaptive Immune Cells ◽  
Age Related ◽  
The Brain ◽  
Age Related Changes

Neuroinflammation and the tissue-resident innate immune cells, the microglia, respond and contribute to neurodegenerative pathology. Although microglia have been the focus of work linking neuroinflammation and associated dementias like Alzheimer’s Disease, the inflammatory milieu of brain is a conglomerate of cross-talk amongst microglia, systemic immune cells and soluble mediators like cytokines. Age-related changes in the inflammatory profile at the levels of both the brain and periphery are largely orchestrated by immune system cells. Strong evidence indicates that both innate and adaptive immune cells, the latter including T cells and B cells, contribute to chronic neuroinflammation and thus dementia. Neurodegenerative hallmarks coupled with more traditional immune system stimuli like infection or injury likely combine to trigger and maintain persistent microglial and thus brain inflammation. This review summarizes age-related changes in immune cell function, with special emphasis on lymphocytes as a source of inflammation, and discusses how such changes may potentiate both systemic and central nervous system inflammation to culminate in dementia. We recap the understudied area of AD-associated changes in systemic lymphocytes in greater detail to provide a unifying perspective of inflammation-fueled dementia, with an eye toward evidence of two-way communication between the brain parenchyma and blood immune cells. We focused our review on human subjects studies, adding key data from animal models as relevant.

scholarly journals Neuroinvasion of SARS-CoV-2 in human and mouse brain

2021 ◽  
Vol 218 (3) ◽  
Author(s):  
Eric Song ◽  
Ce Zhang ◽  
Benjamin Israelow ◽  
Alice Lu-Culligan ◽  
Alba Vieites Prado ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Immune Cell ◽  
Multiple Organ ◽  
Type I ◽  
Organ Systems ◽  
The Central Nervous System ◽  
Interferon Responses ◽  
The Brain ◽  
Immune Cell Infiltrates

Although COVID-19 is considered to be primarily a respiratory disease, SARS-CoV-2 affects multiple organ systems including the central nervous system (CNS). Yet, there is no consensus on the consequences of CNS infections. Here, we used three independent approaches to probe the capacity of SARS-CoV-2 to infect the brain. First, using human brain organoids, we observed clear evidence of infection with accompanying metabolic changes in infected and neighboring neurons. However, no evidence for type I interferon responses was detected. We demonstrate that neuronal infection can be prevented by blocking ACE2 with antibodies or by administering cerebrospinal fluid from a COVID-19 patient. Second, using mice overexpressing human ACE2, we demonstrate SARS-CoV-2 neuroinvasion in vivo. Finally, in autopsies from patients who died of COVID-19, we detect SARS-CoV-2 in cortical neurons and note pathological features associated with infection with minimal immune cell infiltrates. These results provide evidence for the neuroinvasive capacity of SARS-CoV-2 and an unexpected consequence of direct infection of neurons by SARS-CoV-2.

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