Critical role of TRPP2 and TRPC1 channels in stretch-induced injury of blood–brain barrier endothelial cells

Introduction: Laminin, a major component of the basement membrane, plays an important role in blood brain barrier (BBB) regulation. At the neurovascular unit, astrocytes, brain endothelial cells, and pericytes synthesize and deposit different laminin isoforms into the basement membrane. Previous studies from our laboratory showed that loss of astrocytic laminin induces age-dependent and region-specific BBB breakdown and intracerebral hemorrhage, suggesting a critical role of astrocytic laminin in vascular integrity maintenance. Laminin α4 (predominantly generated by endothelial cells) has been shown to regulate vascular integrity at embryonic/neonatal stage. The role of pericytic laminin in vascular integrity, however, remains elusive. Methods: We investigated the function of pericyte-derived laminin in vascular integrity using laminin conditional knockout mice. Specifically, laminin floxed mice were crossed with PDGFRβ-Cre line to generate mutants (PKO) with laminin deficiency in PDGFRβ + cells, which include both pericytes and vascular smooth muscle cells (vSMCs). To distinguish the contribution of pericyte- and vSMC-derived laminin, we also generated a vSMC-specific condition knockout line (TKO) by crossing the laminin floxed mice with Transgelin-Cre mice. In this study, mice of both genders on a C57Bl6 background were used. At least 5-6 animals were used in biochemical and histological analyses in this study. Results: Pericyte-derived laminin was abrogated in all PKO mice. However, only old but not young PKO mice showed signs of BBB breakdown and reduced vessel density, suggesting age-dependent changes. Consistent with these data, further mechanistic studies revealed reduced tight junction proteins, diminished AQP4 expression, and deceased pericyte coverage in old but not young PKO mice. In addition, neither BBB disruption nor decreased vessel density was observed in TKO mice, suggesting that these vascular defects are due to loss of pericyte- rather than vSMC-derived laminin. Conclusions: These results strongly suggest that pericyte-derived laminin active regulates BBB integrity and vessel density in an age-dependent manner. I would like this abstract to be considered for the Stroke Basic Science Award.

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The Dual Role of Microglia in Blood-Brain Barrier Dysfunction after Stroke

Current Neuropharmacology ◽

10.2174/1570159x18666200529150907 ◽

2020 ◽

Vol 18 (12) ◽

pp. 1237-1249 ◽

Cited By ~ 1

Author(s):

Ruiqing Kang ◽

Marcin Gamdzyk ◽

Cameron Lenahan ◽

Jiping Tang ◽

Sheng Tan ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Vital Role ◽

Dual Role ◽

Brain Barrier ◽

Barrier Dysfunction ◽

Blood Brain ◽

M2 Microglia ◽

The Brain

It is well-known that stroke is one of the leading causes of death and disability all over the world. After a stroke, the blood-brain barrier subsequently breaks down. The BBB consists of endothelial cells surrounded by astrocytes. Microglia, considered the long-living resident immune cells of the brain, play a vital role in BBB function. M1 microglia worsen BBB disruption, while M2 microglia assist in repairing BBB damage. Microglia can also directly interact with endothelial cells and affect BBB permeability. In this review, we are going to discuss the mechanisms responsible for the dual role of microglia in BBB dysfunction after stroke.

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The Mechanism of Reversible Osmotic Opening of the Blood-Brain Barrier: Role of Intracellular Calcium Ion in Capillary Endothelial Cells

Brain Edema X ◽

10.1007/978-3-7091-6837-0_71 ◽

1997 ◽

pp. 231-233 ◽

Cited By ~ 1

Author(s):

Tatsuya Nagashima ◽

K. Ikeda ◽

S. Wu ◽

T. Kondo ◽

M. Yamaguehi ◽

...

Keyword(s):

Endothelial Cells ◽

Intracellular Calcium ◽

Blood Brain Barrier ◽

Calcium Ion ◽

Brain Barrier ◽

Blood Brain ◽

Intracellular Calcium Ion ◽

Capillary Endothelial Cells

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Abstract WMP120: Critical Role of RGS5 in Modulating Blood-Brain Barrier Integrity During Focal Cerebral Ischemia

Stroke ◽

10.1161/str.49.suppl_1.wmp120 ◽

2018 ◽

Vol 49 (Suppl_1) ◽

Author(s):

Nikola Sladojevic ◽

James K Liao

Keyword(s):

Cerebral Ischemia ◽

Blood Brain Barrier ◽

Focal Cerebral Ischemia ◽

Critical Role ◽

Brain Barrier ◽

Barrier Integrity ◽

Blood Brain ◽

Blood Brain Barrier Integrity

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Evaluation of the effect of stress on the blood–brain barrier: critical role of the brain perfusion time

Brain Research ◽

10.1016/s0006-8993(01)02361-7 ◽

2001 ◽

Vol 905 (1-2) ◽

pp. 21-25 ◽

Cited By ~ 28

Author(s):

Haim Ovadia ◽

Oded Abramsky ◽

Shaul Feldman ◽

Joseph Weidenfeld

Keyword(s):

Blood Brain Barrier ◽

Critical Role ◽

Brain Perfusion ◽

Brain Barrier ◽

Blood Brain ◽

Perfusion Time ◽

The Brain

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3D Culture and Characterization of Blood-Brain Barrier Endothelial Cells in a New Microfluidic Platform

10.21203/rs.3.rs-100206/v1 ◽

2020 ◽

Author(s):

Sebastian Trennheuser ◽

Felix Schmitt-Hoffner ◽

Anne Mahringer ◽

Lena Mesch ◽

Peter Jones ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Brain Barrier ◽

Drug Transport ◽

Cell Layer ◽

Critical Role ◽

3D Culture ◽

Brain Barrier ◽

Microfluidic Platform ◽

Blood Brain ◽

Hydrogel Matrix

Abstract Background: The blood-brain barrier (BBB) protects the central nervous system (CNS) from harmful substances in the peripheral blood stream and ensures brain homeostasis by regulating the transport of nutrients and metabolites. It also prevents many pharmaceutical drugs from reaching their target site and dysfunctions of the BBB are often associated with CNS diseases. In order to provide a new in vitro platform that allows the investigation of barrier characteristics of the BBB and drug transport under physiological and pathological conditions, the TransBBB system was developed. The microfluidic chip consists of ten parallel culture chambers, each allowing the cultivation of endothelial cells on a physiological matrix under perfusion.Methods: Porcine brain capillary endothelial cells (PBCECs) were cultivated on the surface of a hydrogel matrix resulting in a barrier which separates the culture chambers into two compartments. A protocol was established in order to obtain a tight cell layer under perfusion and the effect of different perfusion volumes on BBB formation was investigated. The barrier was then characterized in terms of cell viability, barrier integrity and expression of tight junction proteins.Results: PBCECs formed a tight cell layer on the hydrogel surface preventing FITC dextran from permeating the cellular barrier. The presence of ZO-1 at the cell borders was shown indicating a functional BBB. The perfusion experiments suggested a critical role of medium volume for cell layer integrity under perfusion conditions.Conclusions: The TransBBB chip presented here provides a promising, scalable microfluidic platform for the investigation of cellular barriers which can be integrated seamlessly into existing cell culture and drug testing workflows.

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Role of NADPH Oxidase-Induced Hypoxia-Induced Factor-1α Increase in Blood-Brain Barrier Disruption after 2-Hour Focal Ischemic Stroke in Rat

Neural Plasticity ◽

10.1155/2021/9928232 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Yanping Wang ◽

Yufei Shen ◽

Xin Yu ◽

Jingxia Gu ◽

Xiaoling Zhang ◽

...

Keyword(s):

Ischemic Stroke ◽

Nadph Oxidase ◽

Acute Ischemic Stroke ◽

Blood Brain Barrier ◽

Critical Role ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Brain Barrier ◽

Blood Brain ◽

Junction Protein

We recently showed that inhibition of hypoxia-induced factor-1α (HIF-1α) decreased acute ischemic stroke-induced blood-brain barrier (BBB) damage. However, factors that induce the upregulation of HIF-1α expression remain unclear. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase played a critical role in reperfusion-induced BBB damage after stroke. However, the role of NADPH oxidase in BBB injury during the acute ischemia stage remains unclear. This study is aimed at investigating the role of NADPH oxidase in BBB injury and the expression of HIF-1α after acute ischemic stroke. A sutured middle cerebral artery occlusion (MCAO) model was used to mimic ischemic stroke in rats. Our results show that the inhibition of NADPH oxidase by apocynin can significantly reduce the BBB damage caused by 2 h ischemic stroke accompanied by reducing the degradation of tight junction protein occludin. In addition, treatment with apocynin significantly decreased the upregulation of HIF-1α induced by 2 h MCAO. More importantly, apocynin could also inhibit the MMP-2 upregulation. Of note, HIF-1α was not colocalized with a bigger blood vessel. Taken together, our results showed that inhibition of NADPH oxidase-mediated HIF-1α upregulation reduced BBB damage accompanied by downregulating MMP-2 expression and occludin degradation after 2 h ischemia stroke. These results explored the mechanism of BBB damage after acute ischemic stroke and may help reduce the associated cerebral hemorrhage transformation after thrombolysis and endovascular treatment after ischemic stroke.

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Disruption in the Blood-Brain Barrier: The Missing Link between Brain and Body Inflammation in Bipolar Disorder?

Neural Plasticity ◽

10.1155/2015/708306 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 78

Author(s):

Jay P. Patel ◽

Benicio N. Frey

Keyword(s):

Bipolar Disorder ◽

Blood Brain Barrier ◽

Peripheral Blood ◽

Critical Role ◽

Brain Barrier ◽

Inflammatory Conditions ◽

Blood Brain ◽

The Central Nervous System ◽

The Brain

The blood-brain barrier (BBB) regulates the transport of micro- and macromolecules between the peripheral blood and the central nervous system (CNS) in order to maintain optimal levels of essential nutrients and neurotransmitters in the brain. In addition, the BBB plays a critical role protecting the CNS against neurotoxins. There has been growing evidence that BBB disruption is associated with brain inflammatory conditions such as Alzheimer’s disease and multiple sclerosis. Considering the increasing role of inflammation and oxidative stress in the pathophysiology of bipolar disorder (BD), here we propose a novel model wherein transient or persistent disruption of BBB integrity is associated with decreased CNS protection and increased permeability of proinflammatory (e.g., cytokines, reactive oxygen species) substances from the peripheral blood into the brain. These events would trigger the activation of microglial cells and promote localized damage to oligodendrocytes and the myelin sheath, ultimately compromising myelination and the integrity of neural circuits. The potential implications for research in this area and directions for future studies are discussed.

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Caspase-1 has a critical role in blood-brain barrier injury and its inhibition contributes to multifaceted repair

Journal of Neuroinflammation ◽

10.1186/s12974-020-01927-w ◽

2020 ◽

Vol 17 (1) ◽

Cited By ~ 2

Author(s):

Hila Israelov ◽

Orly Ravid ◽

Dana Atrakchi ◽

Daniel Rand ◽

Shirin Elhaik ◽

...

Keyword(s):

Blood Brain Barrier ◽

Critical Role ◽

Brain Inflammation ◽

Brain Barrier ◽

Cns Disorders ◽

Caspase 1 ◽

Blood Brain

Abstract Background Excessive inflammation might activate and injure the blood-brain barrier (BBB), a common feature of many central nervous system (CNS) disorders. We previously developed an in vitro BBB injury model in which the organophosphate paraoxon (PX) affects the BBB endothelium by attenuating junctional protein expression leading to weakened barrier integrity. The objective of this study was to investigate the inflammatory cellular response at the BBB to elucidate critical pathways that might lead to effective treatment in CNS pathologies in which the BBB is compromised. We hypothesized that caspase-1, a core component of the inflammasome complex, might have important role in BBB function since accumulating evidence indicates its involvement in brain inflammation and pathophysiology. Methods An in vitro human BBB model was employed to investigate BBB functions related to inflammation, primarily adhesion and transmigration of peripheral blood mononuclear cells (PBMCs). Caspase-1 pathway was studied by measurements of its activation state and its role in PBMCs adhesion, transmigration, and BBB permeability were investigated using the specific caspase-1 inhibitor, VX-765. Expression level of adhesion and junctional molecules and the secretion of pro-inflammatory cytokines were measured in vitro and in vivo at the BBB endothelium after exposure to PX. The potential repair effect of blocking caspase-1 and downstream molecules was evaluated by immunocytochemistry, ELISA, and Nanostring technology. Results PX affected the BBB in vitro by elevating the expression of the adhesion molecules E-selectin and ICAM-1 leading to increased adhesion of PBMCs to endothelial monolayer, followed by elevated transendothelial-migration which was ICAM-1 and LFA-1 dependent. Blocking caspase-8 and 9 rescued the viability of the endothelial cells but not the elevated transmigration of PBMCs. Inhibition of caspase-1, on the other hand, robustly restored all of barrier insults tested including PBMCs adhesion and transmigration, permeability, and VE-cadherin protein levels. The in vitro inflammatory response induced by PX and the role of caspase-1 in BBB injury were corroborated in vivo in isolated blood vessels from hippocampi of mice exposed to PX and treated with VX-765. Conclusions These results shed light on the important role of caspase-1 in BBB insult in general and specifically in the inflamed endothelium, and suggest therapeutic potential for various CNS disorders, by targeting caspase-1 in the injured BBB.

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