scholarly journals Brain Microvascular Endothelial Cell-Derived HMGB1 Facilitates Monocyte Adhesion and Transmigration to Promote JEV Neuroinvasion

2021 ◽  
Vol 11 ◽  
Author(s):  
Song-Song Zou ◽  
Qing-Cui Zou ◽  
Wen-Jing Xiong ◽  
Ning-Yi Cui ◽  
Ke Wang ◽  
...  
Keyword(s):  
Japanese Encephalitis ◽  
Immune Cell ◽  
Microvascular Endothelial Cell ◽  
High Morbidity ◽  
Brain Microvascular Endothelial Cell ◽  
Neurological Sequelae ◽  
The Central Nervous System ◽  
Microvascular Endothelial ◽  
The Brain

Infection with Japanese encephalitis virus (JEV) induces high morbidity and mortality, including potentially permanent neurological sequelae. However, the mechanisms by which viruses cross the blood-brain barrier (BBB) and invade into the central nervous system (CNS) remain unclear. Here, we show that extracellular HMGB1 facilitates immune cell transmigration. Furthermore, the migration of immune cells into the CNS dramatically increases during JEV infection which may enhance viral clearance, but paradoxically expedite the onset of Japanese encephalitis (JE). In this study, brain microvascular endothelial cells (BMECs) were utilized for the detection of HMGB1 release, and leucocyte, adhesion, and the integrity of the BBB in vitro. Genetically modified JEV-expressing EGFP (EGFP-JEV) and the BBB model were established to trace JEV-infected immune cell transmigration, which mimics the process of viral neuroinfection. We find that JEV causes HMGB1 release from BMECs while increasing adhesion molecules. Recombinant HMGB1 enhances leukocyte-endothelium adhesion, facilitating JEV-infected monocyte transmigration across endothelia. Thus, JEV successfully utilizes infected monocytes to spread into the brain, expanding inside of the brain, and leading to the acceleration of JE onset, which was facilitated by HMGB1. HMGB1-promoted monocyte transmigration may represent the mechanism of JEV neuroinvasion, revealing potential therapeutic targets.

scholarly journals Methylglyoxal Impairs Brain Microvascular Endothelial Cell Function In Vivo and In Vitro

2009 ◽  
Vol 96 (3) ◽  
pp. 682a
Author(s):  
Aydin Tay ◽  
William G. Mayhan ◽  
Denise Arrick ◽  
Chun-Hong Shao ◽  
Hong Sun ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Function ◽  
Microvascular Endothelial Cell ◽  
Brain Microvascular Endothelial Cell ◽  
Endothelial Cell Function ◽  
Microvascular Endothelial

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 Shear-Dependent Attenuation of Cellular ROS Levels can Suppress Proinflammatory Cytokine Injury to Human Brain Microvascular Endothelial Barrier Properties

2015 ◽  
Vol 35 (10) ◽  
pp. 1648-1656 ◽  
Author(s):  
Keith D Rochfort ◽  
Laura E Collins ◽  
Alisha McLoughlin ◽  
Philip M Cummins
Keyword(s):  
Human Brain ◽  
Barrier Properties ◽  
Microvascular Endothelial Cell ◽  
Brain Microvascular Endothelial Cell ◽  
Microvascular Endothelium ◽  
Cellular Redox ◽  
Tnf Α ◽  
Microvascular Endothelial ◽  
Laminar Shear ◽  
The Brain

The regulatory interplay between laminar shear stress and proinflammatory cytokines during homeostatic maintenance of the brain microvascular endothelium is largely undefined. We hypothesized that laminar shear could counteract the injurious actions of proinflammatory cytokines on human brain microvascular endothelial cell (HBMvEC) barrier properties, in-part through suppression of cellular redox signaling. For these investigations, HBMvECs were exposed to either shear stress (8 dynes/cm2, 24 hours) or cytokines (tumor necrosis factor-α (TNF-α) or interleukin-6 (IL-6), 0 to 100 ng/mL, 6 or 18 hours). Human brain microvascular endothelial cell ‘preshearing’ ± cytokine exposure was also performed. Either cytokine dose–dependently decreased expression and increased phosphorylation (pTyr/pThr) of interendothelial occludin, claudin-5, and vascular endothelial-cadherin; observations directly correlating to endothelial barrier reduction, and in precise contrast to effects seen with shear. We further observed that, relative to unsheared cells, HBMvECs presheared for 24 hours exhibited significantly reduced reactive oxygen species production and barrier permeabilization in response to either TNF-α or IL-6 treatment. Shear also downregulated NADPH oxidase (nicotinamide adenine dinucleotide phosphate-oxidase) activation in HBMvECs, as manifested in the reduced expression and coassociation of gp91phox and p47phox. These findings lead us to conclude that physiologic shear can protect the brain microvascular endothelium from injurious cytokine effects on interendothelial junctions and barrier function by regulating the cellular redox state in-part through NADPH oxidase inhibition.

scholarly journals Brain Microvascular Endothelial Cells-Derived HMGB1 Facilitates Monocyte Transendothelial Migration Favoring JEV Neuroinvasion

2020 ◽  
Author(s):  
Song-Song Zou ◽  
Qing-Cui Zou ◽  
Wen-Jing Xiong ◽  
Ning-Yi Cui ◽  
Ke Wang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Japanese Encephalitis ◽  
Immune Cells ◽  
Transendothelial Migration ◽  
Trojan Horse ◽  
Microvascular Endothelial Cells ◽  
High Morbidity ◽  
Brain Microvascular Endothelial Cells ◽  
Microvascular Endothelial ◽  
The Brain

Abstract Background: Infection with the Japanese encephalitis virus (JEV) induced high morbidity and mortality, even caused permanent neurological sequelae. However, the pathways and mechanisms of JEV invasion into the central nervous system (CNS) remain elusive. It is confirmed that extracellular HMGB1 facilitates immune cells transendothelial migration. Furthermore, it is observed that the migration of immune cells into the CNS dramatically increased during JEV infection which may benefit to viral clearance, but paradoxically accompanied by the expedite onset of Japanese encephalitis (JE) in advance. Thus, exploration of JEV neuroinvasion pathways is important for pathogenesis and prevention of JE.Methods: Brain microvascular endothelial cells were utilized for the detection of HMGB1 release in vitro. The blood-brain barrier (BBB) monolayer model (brain microvascular endothelial cells) and recombinant HMGB1 were applied for the measurement of endothelial cell activation and cells adhesion, the integrity of the BBB and the interaction with the immune cells. A genetically modified JEV expressing EGFP (EGFP-JEV) was used to trace the transmigration of JEV-infected immune cells crossing the BBB to mimic the process of neuroinfection.Results: JEV has the characteristic of neurotropism, causing HMGB1 released from BMEC and increasing adhesion molecules. BEMC-derived HMGB1 enhances leukocyte-endothelium adhesion, facilitating the transendothelial migration of JEV-infected monocytes across the BBB entry into the CNS. Thus, JEV successfully utilized the monocyte as a “Trojan horse” to spread the virus to the brain, expanding the brain infection, leading the acceleration of JE onset.Conclusion: JEV-infected monocytes, acting as “Trojan horse”, migrate to the brain, which was facilitated by BMEC-derived HMGB1, contributing to JEV neuroinvasion, and leading neuroinflammation and pathological changes of JE.

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.

Abstract 383: Characterization of Inflammatory Cytokine Effects on the Blood-Brain Barrier Using an in Vitro Human Brain Microvascular Endothelial Cell Model

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Keith D Rochfort ◽  
Fiona A Martin ◽  
Ronan P Murphy ◽  
Philip M Cummins
Keyword(s):  
Endothelial Cell ◽  
Tight Junction ◽  
Human Brain ◽  
Tnf Alpha ◽  
Microvascular Endothelial Cell ◽  
Brain Microvascular Endothelial Cell ◽  
Dose Time ◽  
Junctional Proteins ◽  
Microvascular Endothelial

Introduction: The blood-brain barrier (BBB) represents a restrictive interface between the circulation and CNS. Within the multicellular neurovascular unit (NVU), the microvascular endothelium resides at the forefront of this dynamic barrier in direct contact with blood. Following cerebrovascular injury (e.g. ischemic stroke, trauma, infection), inflammatory cytokines are released by NVU cells (neurons, astrocytes, pericytes, endothelial cells) and circulating immune cells, often leading to elevated microvessel permeability and pathology. Much has yet to be uncovered however about how cytokines specifically impact endothelial BBB phenotype at the molecular level. In the present study, we investigated how TNF Alpha and IL-6 affect adherens/tight junction assembly using a human brain microvascular endothelial cell (HBMVEC) model in vitro . Methods: Cultured HBMVECs were exposed to either TNF Alpha or IL-6 over a range of doses (1-100 ng/ml) and times (6 and 18 hours). Cytokine levels were monitored by both standard and multiplex ELISA. Endothelial barrier phenotype was routinely monitored with respect to paracellular permeability (transwell monolayer assay) and junctional protein expression (qRT-PCR & Western blotting). Results: (i) Both TNF Alpha and IL6 treatments increased HBMVEC permeability in a dose- and time-dependent manner. Treatments also increased cell proliferation whilst having minimal impact on cell viability (as monitored by FACS, MTS, LDH and xCelligence assays); (ii) In parallel with permeability increases, cytokine treatments dose-/time-dependently decreased mRNA and protein levels for tight junction-associated occludin, zonnula occludens-1 and claudin-5, as well as for adherens junction-associated VE-cadherin; (iii) TNF Alpha treatment was also seen to dose-/time-dependently induce IL-6 expression and release from HBMVECs. Conclusions: Inflammatory cytokines (TNF Alpha and IL-6) reduce microvascular endothelial BBB integrity in-part through a mechanism involving reduced synthesis of junctional proteins. Cytokine-mediated post-translational modification of junctional proteins (e.g. occludin phosphorylation and ubiquitination) is also suspected in these events. Moreover, the TNF Alpha-stimulated production/release of IL-6 may reflect a putative mechanism through which the former cytokine elicits BBB compromise.

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