Modulation of tight junction structure in blood-brain barrier endothelial cells. Effects of tissue culture, second messengers and cocultured astrocytes

1994 ◽  
Vol 107 (5) ◽  
pp. 1347-1357 ◽  
Author(s):  
H. Wolburg ◽  
J. Neuhaus ◽  
U. Kniesel ◽  
B. Krauss ◽  
E.M. Schmid ◽  
...  

Tight junctions between endothelial cells of brain capillaries are the most important structural elements of the blood-brain barrier. Cultured brain endothelial cells are known to loose tight junction-dependent blood-brain barrier characteristics such as macromolecular impermeability and high electrical resistance. We have directly analyzed the structure and function of tight junctions in primary cultures of bovine brain endothelial cells using quantitative freeze-fracture electron microscopy, and ion and inulin permeability. The complexity of tight junctions, defined as the number of branch points per unit length of tight junctional strands, decreased 5 hours after culture but thereafter remained almost constant. In contrast, the association of tight junction particles with the cytoplasmic leaflet of the endothelial membrane bilayer (P-face) decreased continuously with a major drop between 16 hours and 24 hours. The complexity of tight junctions could be increased by elevation of intracellular cAMP levels while phorbol esters had the opposite effect. On the other hand, the P-face association of tight junction particles was enhanced by elevation of cAMP levels and by coculture of endothelial cells with astrocytes or exposure to astrocyte-conditioned medium. The latter effect on P-face association was induced by astrocytes but not fibroblasts. Elevation of cAMP levels together with astrocyte-conditioned medium synergistically increased transendothelial electrical resistance and decreased inulin permeability of primary cultures, thus confirming the effects on tight junction structure and barrier function. P-face association of tight junction particles in brain endothelial cells may therefore be a critical feature of blood-brain barrier function that can be specifically modulated by astrocytes and cAMP levels. Our results suggest an important functional role for the cytoplasmic anchorage of tight junction particles for brain endothelial barrier function in particular and probably paracellular permeability in general.

2018 ◽  
Vol 315 (3) ◽  
pp. C343-C356 ◽  
Author(s):  
Wazir Abdullahi ◽  
Dinesh Tripathi ◽  
Patrick T. Ronaldson

The blood-brain barrier (BBB) is a physical and biochemical barrier that precisely controls cerebral homeostasis. It also plays a central role in the regulation of blood-to-brain flux of endogenous and exogenous xenobiotics and associated metabolites. This is accomplished by molecular characteristics of brain microvessel endothelial cells such as tight junction protein complexes and functional expression of influx and efflux transporters. One of the pathophysiological features of ischemic stroke is disruption of the BBB, which significantly contributes to development of brain injury and subsequent neurological impairment. Biochemical characteristics of BBB damage include decreased expression and altered organization of tight junction constituent proteins as well as modulation of functional expression of endogenous BBB transporters. Therefore, there is a critical need for development of novel therapeutic strategies that can protect against BBB dysfunction (i.e., vascular protection) in the setting of ischemic stroke. Such strategies include targeting tight junctions to ensure that they maintain their correct structure or targeting transporters to control flux of physiological substrates for protection of endothelial homeostasis. In this review, we will describe the pathophysiological mechanisms in cerebral microvascular endothelial cells that lead to BBB dysfunction following onset of stroke. Additionally, we will utilize this state-of-the-art knowledge to provide insights on novel pharmacological strategies that can be developed to confer BBB protection in the setting of ischemic stroke.


2019 ◽  
Vol 10 ◽  
pp. 941-954 ◽  
Author(s):  
Aniela Bittner ◽  
Angélique D Ducray ◽  
Hans Rudolf Widmer ◽  
Michael H Stoffel ◽  
Meike Mevissen

Nanomedicine is a constantly expanding field, facilitating and improving diagnosis and treatment of diseases. As nanomaterials are foreign objects, careful evaluation of their toxicological and functional aspects prior to medical application is imperative. In this study, we aimed to determine the effects of gold and polymer-coated silica nanoparticles used in laser tissue soldering on brain endothelial cells and the blood–brain barrier using rat brain capillary endothelial cells (rBCEC4). All types of nanoparticles were taken up time-dependently by the rBCEC4 cells, albeit to a different extent, causing a time- and concentration-dependent decrease in cell viability. Nanoparticle exposure did not change cell proliferation, differentiation, nor did it induce inflammation. rBCEC4 cells showed blood–brain barrier characteristics including tight junctions. None of the nanoparticles altered the expression of tight junctions or impaired the blood–brain barrier permeability. The findings suggest that effects of these nanoparticles on the metabolic state of cells have to be further characterized before use for medical purposes.


2007 ◽  
Vol 1159 ◽  
pp. 67-76 ◽  
Author(s):  
Joseph C. Lim ◽  
Adam J. Wolpaw ◽  
Maeve A. Caldwell ◽  
Stephen B. Hladky ◽  
Margery A. Barrand

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1484
Author(s):  
Daisuke Watanabe ◽  
Shinsuke Nakagawa ◽  
Yoichi Morofuji ◽  
Andrea E. Tóth ◽  
Monika Vastag ◽  
...  

Culture models of the blood-brain barrier (BBB) are important research tools. Their role in the preclinical phase of drug development to estimate the permeability for potential neuropharmaceuticals is especially relevant. Since species differences in BBB transport systems exist, primate models are considered as predictive for drug transport to brain in humans. Based on our previous expertise we have developed and characterized a non-human primate co-culture BBB model using primary cultures of monkey brain endothelial cells, rat brain pericytes, and rat astrocytes. Monkey brain endothelial cells in the presence of both pericytes and astrocytes (EPA model) expressed enhanced barrier properties and increased levels of tight junction proteins occludin, claudin-5, and ZO-1. Co-culture conditions also elevated the expression of key BBB influx and efflux transporters, including glucose transporter-1, MFSD2A, ABCB1, and ABCG2. The correlation between the endothelial permeability coefficients of 10 well known drugs was higher (R2 = 0.8788) when the monkey and rat BBB culture models were compared than when the monkey culture model was compared to mouse in vivo data (R2 = 0.6619), hinting at transporter differences. The applicability of the new non-human primate model in drug discovery has been proven in several studies.


2020 ◽  
Author(s):  
Xiaoqing Li ◽  
Vamsidhara Vemireddy ◽  
Qi Cai ◽  
Hejian Xiong ◽  
Peiyuan Kang ◽  
...  

AbstractThe blood-brain barrier (BBB) tightly regulates the entry of molecules into the brain by tight junctions that seals the paracellular space and receptor-mediated transcytosis. It remains elusive to selectively modulate these mechanisms and to overcome BBB without significant neurotoxicity. Here we report that light stimulation of tight junction-targeted plasmonic nanoparticles selectively opens up the paracellular route to allow diffusion through the compromised tight junction and into the brain parenchyma. The BBB modulation does not impair vascular dynamics and associated neurovascular coupling, or cause significant neural injury. It further allows antibody and adeno-associated virus delivery into local brain regions. This novel method offers the first evidence of selectively modulating BBB tight junctions and opens new avenues for therapeutic interventions in the central nervous system.One Sentence SummaryGentle stimulation of molecular-targeted nanoparticles selectively opens up the paracellular pathway and allows macromolecules and gene therapy vectors into the brain.


2021 ◽  
Author(s):  
Kei Sato ◽  
Shinsuke Nakagawa ◽  
Yoichi Morofuji ◽  
Yuki Matsunaga ◽  
Takashi Fujimoto ◽  
...  

Abstract Background Cerebral infarction accounts for 85% of all stroke cases. Even in an era of rapid and effective recanalization using an intravascular approach, the majority of patients have poor functional outcomes. Thus, there is an urgent need for the development of therapeutic agents to treat acute ischemic stroke. We evaluated the effect of fasudil, a Rho kinase inhibitor, on blood brain barrier (BBB) functions under normoxia or oxygen-glucose deprivation (OGD) conditions using a primary cell-based in vitro BBB model. Medhods: BBB models from rat primary cultures (brain capillary endothelial cells, astrocytes, and pericytes) were subjected to either normoxia or 6-hour OGD/24-hour reoxygenation. To assess the effects of fasudil on BBB functions, we evaluated real time impedance, transendothelial electrical resistance (TEER), sodium fluorescein permeability, and tight junction protein expression using immunohistochemistry and western blotting. Lastly, to understand the observed protective mechanism on BBB functions by fasudil we examined the role of cyclooxygenase-2 and thromboxane A2 receptor agonist U-46619 in BBB-forming cells. Results We found that treatment with 0.3–30 µM of fasudil increased cellular impedance. Fasudil enhanced barrier properties in a concentration-dependent manner, as measured by an increased (TEER) and decreased permeability. Fasudil also increased the expression of tight junction protein claudin-5. Reductions in TEER and increased permeability were observed after OGD/reoxygenation exposure in mono- and co-culture models. The improvement in BBB integrity by fasudil was confirmed in both of the models, but was significantly higher in the co-culture than in the monoculture model. Treatment with U-46619 did not show significant changes in TEER in the monoculture model, whereas it showed a significant reduction in TEER in the co-culture model. Fasudil significantly improved the U-46619-induced TEER reduction in the co-culture models. Pericytes and astrocytes have opposite effects on endothelial cells and may contribute to endothelial injury in hyperacute ischemic stroke. Overall, fasudil protects the integrity of BBB both by a direct protective effect on endothelial cells and by a pathway mediated via pericytes and astrocytes. Conclusions Our findings suggest that fasudil is a BBB-protective agent against acute ischemic stroke.


PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e115981 ◽  
Author(s):  
Shijie Jin ◽  
Yoshifumi Sonobe ◽  
Jun Kawanokuchi ◽  
Hiroshi Horiuchi ◽  
Yi Cheng ◽  
...  

2003 ◽  
pp. 565-568 ◽  
Author(s):  
Bela Kis ◽  
J. A. Snipes ◽  
M. A. Deli ◽  
C. S. Ábrahám ◽  
H. Yamashita ◽  
...  

2019 ◽  
Vol 20 (3) ◽  
pp. 602 ◽  
Author(s):  
Axel Haarmann ◽  
Michael Schuhmann ◽  
Christine Silwedel ◽  
Camelia-Maria Monoranu ◽  
Guido Stoll ◽  
...  

Chemokines (C-X-C) motif ligand (CXCL) 5 and 8 are overexpressed in patients with multiple sclerosis, where CXCL5 serum levels were shown to correlate with blood–brain barrier dysfunction as evidenced by gadolinium-enhanced magnetic resonance imaging. Here, we studied the potential role of CXCL5/CXCL8 receptor 2 (CXCR2) as a regulator of paraendothelial brain barrier function, using the well-characterized human cerebral microvascular endothelial cell line hCMEC/D3. Low basal CXCR2 mRNA and protein expression levels in hCMEC/D3 were found to strongly increase under inflammatory conditions. Correspondingly, immunohistochemistry of brain biopsies from two patients with active multiple sclerosis revealed upregulation of endothelial CXCR2 compared to healthy control tissue. Recombinant CXCL5 or CXCL8 rapidly and transiently activated Akt/protein kinase B in hCMEC/D3. This was followed by a redistribution of tight junction-associated protein zonula occludens-1 (ZO-1) and by the formation of actin stress fibers. Functionally, these morphological changes corresponded to a decrease of paracellular barrier function, as measured by a real-time electrical impedance-sensing system. Importantly, preincubation with the selective CXCR2 antagonist SB332235 partially prevented chemokine-induced disturbance of both tight junction morphology and function. We conclude that human brain endothelial CXCR2 may contribute to blood–brain barrier disturbance under inflammatory conditions with increased CXCL5 and CXCL8 expression, where CXCR2 may also represent a novel pharmacological target for blood–brain barrier stabilization.


Sign in / Sign up

Export Citation Format

Share Document