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 trafficking across the blood-brain barrier in the absence and presence of neuroinflammation

2020 ◽  
Vol 2 (1) ◽  
pp. H1-H18 ◽  
Author(s):  
Luca Marchetti ◽  
Britta Engelhardt
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Immune Cells ◽  
Immune Cell ◽  
Brain Barrier ◽  
Proper Function ◽  
Cell Trafficking ◽  
Immune Cell Trafficking ◽  
Blood Brain

To maintain the homeostatic environment required for proper function of CNS neurons the endothelial cells of CNS microvessels tightly regulate the movement of ions and molecules between the blood and the CNS. The unique properties of these blood vascular endothelial cells are termed blood-brain barrier (BBB) and extend to regulating immune cell trafficking into the immune privileged CNS during health and disease. In general, extravasation of circulating immune cells is a multi-step process regulated by the sequential interaction of adhesion and signalling molecules between the endothelial cells and the immune cells. Accounting for the unique barrier properties of CNS microvessels, immune cell migration across the BBB is distinct and characterized by several adaptations. Here we describe the mechanisms that regulate immune cell trafficking across the BBB during immune surveillance and neuroinflammation, with a focus on the current state-of-the-art in vitro and in vivo imaging observations.

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.

Thiamine transport in the central nervous system

1976 ◽  
Vol 230 (4) ◽  
pp. 1101-1107 ◽  
Author(s):  
R Spector
Keyword(s):  
Choroid Plexus ◽  
Intraventricular Injection ◽  
Simple Diffusion ◽  
Thiamine Transport ◽  
Choroid Plexuses ◽  
The Central Nervous System ◽  
The Brain ◽  
Thiamine Phosphates

Total thiamine (free thiamine and thiamine phosphates) transport into the cerebrospinal fluid (CSF), brain, and choroid plexus and out of the CSF was measured in rabbits. In vivo, total thiamine transport into CSF, choroid plexus, and brain was saturable. At the normal plasma total thiamine concentration, less than 5% of total thiamine entry into CSF, choroid plexus, and brain was by simple diffusion. The relative turnovers of total thiamine in choroid plexus, whole brain, and CSF were 5, 2, and 14% per h, respectively, when measured by the penetration of 35S-labeled thiamine injected into blood. From the CSF, clearance of [35S]thiamine relative to mannitol was not saturable after the intraventricular injection of various concentrations of thiamine. However, a portion of the [35S]thiamine cleared from the CSF entered brain by a saturable mechanism. In vitro, choroid plexuses, isolated from rabbits and incubated in artificial CSF, accumulated [35S]thiamine against a concentration gradient by an active saturable process that did not depend on pyrophosphorylation of the [35S]thiamine. The [35S]thiamine accumulated within the choroid plexus in vitro was readily released. These results were interpreted as showing that the entry of total thiamine into the brain and CSF from blood is regulated by a saturable transport system, and that the locus of this system may be, in part, in the choroid plexus.

scholarly journals Vascular Dysfunction Induced by Mercury Exposure

2019 ◽  
Vol 20 (10) ◽  
pp. 2435 ◽  
Author(s):  
Tetsuya Takahashi ◽  
Takayoshi Shimohata
Keyword(s):  
Oxidative Stress ◽  
Vascular Dysfunction ◽  
Brain Parenchyma ◽  
Transport Systems ◽  
Mehg Exposure ◽  
In Vivo Models ◽  
The Central Nervous System ◽  
The Brain

Methylmercury (MeHg) causes severe damage to the central nervous system, and there is increasing evidence of the association between MeHg exposure and vascular dysfunction, hemorrhage, and edema in the brain, but not in other organs of patients with acute MeHg intoxication. These observations suggest that MeHg possibly causes blood–brain barrier (BBB) damage. MeHg penetrates the BBB into the brain parenchyma via active transport systems, mainly the l-type amino acid transporter 1, on endothelial cell membranes. Recently, exposure to mercury has significantly increased. Numerous reports suggest that long-term low-level MeHg exposure can impair endothelial function and increase the risks of cardiovascular disease. The most widely reported mechanism of MeHg toxicity is oxidative stress and related pathways, such as neuroinflammation. BBB dysfunction has been suggested by both in vitro and in vivo models of MeHg intoxication. Therapy targeted at both maintaining the BBB and suppressing oxidative stress may represent a promising therapeutic strategy for MeHg intoxication. This paper reviews studies on the relationship between MeHg exposure and vascular dysfunction, with a special emphasis on the BBB.

A new in vitro system for studying secondary palate development

Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 485-495
Author(s):  
L. Brinkley ◽  
G. Basehoar ◽  
A. Branch ◽  
J. Avery
Keyword(s):  
Gas Permeation ◽  
Present System ◽  
Embryonic Mouse ◽  
Fluid Medium ◽  
In Vitro System ◽  
Palate Development ◽  
Fixed Orientation ◽  
The Brain

An in vitro system was devised which supports palate development in partially dissected embryonic mouse heads. The heads were suspended in the culture chamber so that they were not held in a fixed orientation and were constantly surrounded with a fluid medium. Under these circumstances the developing palate must effect closure without the aid of gravitational forces. The culture medium was constantly circulated, gassed with 95% O2, 5% CO2 using hollow fiber gas permeation devices, and kept at 34°C. Swiss-Webster mouse embryos of 12 days 12–18 h (ca. 48 h prior to expected in vivo closure) or 13 days 8–14 h (ca. 24 h prior to closure) were used to test the ability of the system to support palatal development. Embryonic heads were dissected in one of two ways before culture: brain and tongue removed, or brain, tongue and mandible removed. After 24 h in culture, preparations of either age with only the brain and tongue removed had made substantially greater progress than their counterparts with the brain, tongue and mandible removed. With only the brain and tongue removed, the palatal shelves were contacting, adhered or fused in 67 % of the older embryos, whereas most of the embryos of the same age cultured with the brain, tongue and mandible removed had shelves that were not fully elevated and still separated by a moderate gap. Thus for maximal progress in the present system, the oral cavity must be intact except for the tongue.

scholarly journals Cellular MR Imaging

2005 ◽  
Vol 4 (3) ◽  
pp. 153535002005051 ◽  
Author(s):  
Michel Modo ◽  
Mathias Hoehn ◽  
Jeff W.M. Bulte
Keyword(s):  
Mr Imaging ◽  
Contrast Agents ◽  
Immune Cell ◽  
Late Phase ◽  
Superparamagnetic Iron Oxide ◽  
Cell Trafficking ◽  
Macrophage Activity ◽  
Active Research

Cellular MR imaging is a young field that aims to visualize targeted cells in living organisms. In order to provide a different signal intensity of the targeted cell, they are either labeled with MR contrast agents in vivo or prelabeled in vitro. Either (ultrasmall) superparamagnetic iron oxide [(U)SPIO] particles or (polymeric) paramagnetic chelates can be used for this purpose. For in vivo cellular labeling, Gd3+- and Mn2+- chelates have mainly been used for targeted hepatobiliary imaging, and (U)SPIO-based cellular imaging has been focused on imaging of macrophage activity. Several of these magneto-pharmaceuticals have been FDA-approved or are in late-phase clinical trials. As for prelabeling of cells in vitro, a challenge has been to induce a sufficient uptake of contrast agents into nonphagocytic cells, without affecting normal cellular function. It appears that this issue has now largely been resolved, leading to an active research on monitoring the cellular biodistribution in vivo following transplantation or transfusion of these cells, including cell migration and trafficking. New applications of cellular MR imaging will be directed, for instance, towards our understanding of hematopoietic (immune) cell trafficking and of novel guided (stem) cell-based therapies aimed to be translated to the clinic in the future.

scholarly journals Migration ofAntigen-Specific T Cells Away from CXCR4-Binding Human ImmunodeficiencyVirus Type 1gp120

2004 ◽  
Vol 78 (10) ◽  
pp. 5184-5193 ◽  
Author(s):  
Diana M. Brainard ◽  
William G. Tharp ◽  
Elva Granado ◽  
Nicholas Miller ◽  
Alicja K. Trocha ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cell ◽  
Active Movement ◽  
Target Cells ◽  
Cell Mediated Immunity ◽  
Cell Trafficking ◽  
Hiv 1

ABSTRACT Cell-mediated immunity depends in part on appropriate migration and localization of cytotoxic T lymphocytes (CTL), a process regulated by chemokines and adhesion molecules. Many viruses, including human immunodeficiency virus type 1 (HIV-1), encode chemotactically active proteins, suggesting that dysregulation of immune cell trafficking may be a strategy for immune evasion. HIV-1 gp120, a retroviral envelope protein, has been shown to act as a T-cell chemoattractant via binding to the chemokine receptor and HIV-1 coreceptor CXCR4. We have previously shown that T cells move away from the chemokine stromal cell-derived factor 1 (SDF-1) in a concentration-dependent and CXCR4 receptor-mediated manner. Here, we demonstrate that CXCR4-binding HIV-1 X4 gp120 causes the movement of T cells, including HIV-specific CTL, away from high concentrations of the viral protein. This migratory response is CD4 independent and inhibited by anti-CXCR4 antibodies and pertussis toxin. Additionally, the expression of X4 gp120 by target cells reduces CTL efficacy in an in vitro system designed to account for the effect of cell migration on the ability of CTL to kill their target cells. Recombinant X4 gp120 also significantly reduced antigen-specific T-cell infiltration at a site of antigen challenge in vivo. The repellant activity of HIV-1 gp120 on immune cells in vitro and in vivo was shown to be dependent on the V2 and V3 loops of HIV-1 gp120. These data suggest that the active movement of T cells away from CXCR4-binding HIV-1 gp120, which we previously termed fugetaxis, may provide a novel mechanism by which HIV-1 evades challenge by immune effector cells in vivo.

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 GFAP hyperpalmitoylation exacerbates astrogliosis and neurodegenerative pathology in PPT1-deficient mice

2021 ◽  
Vol 118 (13) ◽  
pp. e2022261118
Author(s):  
Wei Yuan ◽  
Liaoxun Lu ◽  
Muding Rao ◽  
Yang Huang ◽  
Chun-e Liu ◽  
...  
Keyword(s):  
Neuronal Ceroid Lipofuscinosis ◽  
Astrocyte Proliferation ◽  
Infantile Neuronal Ceroid Lipofuscinosis ◽  
Protein Palmitoylation ◽  
Neurodegenerative Pathology ◽  
The Central Nervous System ◽  
Proliferation In Vitro ◽  
The Brain

The homeostasis of protein palmitoylation and depalmitoylation is essential for proper physiological functions in various tissues, in particular the central nervous system (CNS). The dysfunction of PPT1 (PPT1-KI, infantile neuronal ceroid lipofuscinosis [INCL] mouse model), which catalyze the depalmitoylation process, results in serious neurodegeneration accompanied by severe astrogliosis in the brain. Endeavoring to determine critical factors that might account for the pathogenesis in CNS by palm-proteomics, glial fibrillary acidic protein (GFAP) was spotted, indicating that GFAP is probably palmitoylated. Questions concerning if GFAP is indeed palmitoylated in vivo and how palmitoylation of GFAP might participate in neural pathology remain unexplored and are waiting to be investigated. Here we show that GFAP is readily palmitoylated in vitro and in vivo; specifically, cysteine-291 is the unique palmitoylated residue in GFAP. Interestingly, it was found that palmitoylated GFAP promotes astrocyte proliferation in vitro. Furthermore, we showed that PPT1 depalmitoylates GFAP, and the level of palmitoylated GFAP is overwhelmingly up-regulated in PPT1-knockin mice, which lead us to speculate that the elevated level of palmitoylated GFAP might accelerate astrocyte proliferation in vivo and ultimately led to astrogliosis in INCL. Indeed, blocking palmitoylation by mutating cysteine-291 into alanine in GFAP attenuate astrogliosis, and remarkably, the concurrent neurodegenerative pathology in PPT1-knockin mice. Together, these findings demonstrate that hyperpalmitoylated GFAP plays critical roles in regulating the pathogenesis of astrogliosis and neurodegeneration in the CNS, and most importantly, pinpointing that cysteine-291 in GFAP might be a valuable pharmaceutical target for treating INCL and other potential neurodegenerative diseases.

scholarly journals Drug Penetration into the Central Nervous System: Pharmacokinetic Concepts and In Vitro Model Systems

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1542
Author(s):  
Felix Neumaier ◽  
Boris D. Zlatopolskiy ◽  
Bernd Neumaier
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Model Systems ◽  
Pharmacokinetic Parameters ◽  
Special Focus ◽  
Drug Penetration ◽  
The Central Nervous System ◽  
The Brain

Delivery of most drugs into the central nervous system (CNS) is restricted by the blood–brain barrier (BBB), which remains a significant bottleneck for development of novel CNS-targeted therapeutics or molecular tracers for neuroimaging. Consistent failure to reliably predict drug efficiency based on single measures for the rate or extent of brain penetration has led to the emergence of a more holistic framework that integrates data from various in vivo, in situ and in vitro assays to obtain a comprehensive description of drug delivery to and distribution within the brain. Coupled with ongoing development of suitable in vitro BBB models, this integrated approach promises to reduce the incidence of costly late-stage failures in CNS drug development, and could help to overcome some of the technical, economic and ethical issues associated with in vivo studies in animal models. Here, we provide an overview of BBB structure and function in vivo, and a summary of the pharmacokinetic parameters that can be used to determine and predict the rate and extent of drug penetration into the brain. We also review different in vitro models with regard to their inherent shortcomings and potential usefulness for development of fast-acting drugs or neurotracers labeled with short-lived radionuclides. In this regard, a special focus has been set on those systems that are sufficiently well established to be used in laboratories without significant bioengineering expertise.

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