Structural alterations of tight junctions are associated with loss of polarity in stroke-prone spontaneously hypertensive rat blood–brain barrier endothelial cells

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.

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Defective Function of the Blood–Brain Barrier in a Stroke-Prone Spontaneously Hypertensive Rat: Evaluation in an In Vitro Cell Culture Model

Cellular and Molecular Neurobiology ◽

10.1007/s10571-020-00917-z ◽

2020 ◽

Author(s):

Shinsuke Nakagawa ◽

Hiroki Ohara ◽

Masami Niwa ◽

Kazuo Yamagata ◽

Toru Nabika

Keyword(s):

Cell Culture ◽

Blood Brain Barrier ◽

Spontaneously Hypertensive Rat ◽

Brain Barrier ◽

Cell Culture Model ◽

Spontaneously Hypertensive ◽

In Vitro Cell Culture ◽

Blood Brain ◽

Culture Model

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Abstract 034: Opposite Effects of Hypertension and Training on Blood Brain Barrier Integrity in Autonomic Areas of the Spontaneously Hypertensive Rat

Hypertension ◽

10.1161/hyp.66.suppl_1.034 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Lisete C Michelini ◽

Maria T Jordao ◽

Alexandre Ceroni ◽

Leila Buttler

Keyword(s):

Blood Brain Barrier ◽

Spontaneously Hypertensive Rat ◽

Conscious State ◽

Brain Parenchyma ◽

Brain Barrier ◽

Spontaneously Hypertensive ◽

Area Of Interest ◽

Blood Brain ◽

Spontaneous Baroreflex ◽

Blood Brain Barrier Integrity

It is well known that chronic hypertensive rats exhibit deficient blood brain barrier (BBB). We evaluate age-induced progression of BBB lesion in autonomic areas of the SHR and the possible effect of aerobic training on BBB integrity. SHR aged 1, 3 and 5 month were chronically cannulated for hemodynamic recordings in the conscious state (femoral), followed by anesthesia and dextrans’ infusion (FITC-10kDA + RHO-70kDA, carotid artery). Twenty minutes later rats were sacrificed, brains were removed, post-fixed and cryoprotected. BBB permeability was evaluated in sequential 30 μm slices of the hypothalamic paraventricular nucleus (PVN), nucleus tractus solitarii (NTS) and rostroventrolateral medulla (RVLM) by the capability of FITC10 to leak into the brain parenchyma (in % area/area of interest, fluorescent microscope, ImageJ analysis). Other 3-months old SHR were submitted to treadmill training (T=55% of maximum capacity, 1h/day, 5 d/week) or kept sedentary for 8 weeks. Age-matched WKY served as control. Although SHR aged 1 month were normotensive and exhibited no BBB leakage (0.02±0.01 to 0.15±0.03% in all areas, values similar to WKY), leakage augmented sharply with the establishment of hypertension (average of 8.1±0.7% in SHR-3mo, 9.3±1.2% in SHR-5mo). In the WKY, there was only a small age-induced increase in BBB leakage (average of 0.63±0.05% in PVN, NTS and RVLM). Interestingly T promptly reduced dye leakage in the 3 autonomic areas of the SHR (~1.0±0.2% from 2 up to 8 weeks of training) without changing the leakage in PVN, NTS and RVLM of WKY rats and within the hypoglossus nucleus of the SHR (a non-autonomic area). T-induced improvement of BBB integrity in autonomic areas of the SHR were accompanied by significant reductions of HR (-10%) and MAP (-13%), increased HR variability (+2.1-fold), decreased pressure variability (-49%) and increased spontaneous baroreflex sensitivity (+2.3-fold). Data show that BBB lesion in SHR is caused by the establishment of hypertension and that T improves perfusion of autonomic brain areas in hypertensive individuals by preserving BBB integrity. This adaptive response is crucial for a near normal neuronal activity, thus normalizing autonomic control of the circulation even in the presence of hypertension.

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Resveratrol Protects against Oxidized LDL-Induced Breakage of the Blood-Brain Barrier by Lessening Disruption of Tight Junctions and Apoptotic Insults to Mouse Cerebrovascular Endothelial Cells

Journal of Nutrition ◽

10.3945/jn.110.123505 ◽

2010 ◽

Vol 140 (12) ◽

pp. 2187-2192 ◽

Cited By ~ 58

Author(s):

Yi-Ling Lin ◽

Huai-Chia Chang ◽

Ta-Liang Chen ◽

Jin-Han Chang ◽

Wen-Ta Chiu ◽

...

Keyword(s):

Endothelial Cells ◽

Tight Junctions ◽

Blood Brain Barrier ◽

Oxidized Ldl ◽

Brain Barrier ◽

Blood Brain ◽

Cerebrovascular Endothelial Cells

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Size-selective loosening of the blood-brain barrier in claudin-5–deficient mice

The Journal of Cell Biology ◽

10.1083/jcb.200302070 ◽

2003 ◽

Vol 161 (3) ◽

pp. 653-660 ◽

Cited By ~ 1079

Author(s):

Takehiro Nitta ◽

Masaki Hata ◽

Shimpei Gotoh ◽

Yoshiteru Seo ◽

Hiroyuki Sasaki ◽

...

Keyword(s):

Central Nervous System ◽

Endothelial Cells ◽

Nervous System ◽

Blood Vessels ◽

Tight Junctions ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Blood Brain ◽

The Central Nervous System ◽

Deficient Mice

Tight junctions are well-developed between adjacent endothelial cells of blood vessels in the central nervous system, and play a central role in establishing the blood-brain barrier (BBB). Claudin-5 is a major cell adhesion molecule of tight junctions in brain endothelial cells. To examine its possible involvement in the BBB, claudin-5–deficient mice were generated. In the brains of these mice, the development and morphology of blood vessels were not altered, showing no bleeding or edema. However, tracer experiments and magnetic resonance imaging revealed that in these mice, the BBB against small molecules (<800 D), but not larger molecules, was selectively affected. This unexpected finding (i.e., the size-selective loosening of the BBB) not only provides new insight into the basic molecular physiology of BBB but also opens a new way to deliver potential drugs across the BBB into the central nervous system.

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Hormones and the blood-brain barrier

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci-2014-0042 ◽

2015 ◽

Vol 21 (3) ◽

Cited By ~ 6

Author(s):

Richard Hampl ◽

Marie Bičíková ◽

Lucie Sosvorová

Keyword(s):

Endothelial Cells ◽

Tight Junctions ◽

Blood Brain Barrier ◽

Energy Homeostasis ◽

Brain Structures ◽

Brain Barrier ◽

Selection Function ◽

Membrane Structures ◽

Blood Brain ◽

The Brain

AbstractHormones exert many actions in the brain, and brain cells are also hormonally active. To reach their targets in brain structures, hormones must overcome the blood-brain barrier (BBB). The BBB is a unique device selecting desired/undesired molecules to reach or leave the brain, and it is composed of endothelial cells forming the brain vasculature. These cells differ from other endothelial cells in their almost impermeable tight junctions and in possessing several membrane structures such as receptors, transporters, and metabolically active molecules, ensuring their selection function. The main ways how compounds pass through the BBB are briefly outlined in this review. The main part concerns the transport of major classes of hormones: steroids, including neurosteroids, thyroid hormones, insulin, and other peptide hormones regulating energy homeostasis, growth hormone, and also various cytokines. Peptide transporters mediating the saturable transport of individual classes of hormones are reviewed. The last paragraph provides examples of how hormones affect the permeability and function of the BBB either at the level of tight junctions or by various transporters.

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Rho-mediated regulation of tight junctions during monocyte migration across the blood-brain barrier in HIV-1 encephalitis (HIVE)

Blood ◽

10.1182/blood-2005-11-4721 ◽

2006 ◽

Vol 107 (12) ◽

pp. 4770-4780 ◽

Cited By ~ 141

Author(s):

Yuri Persidsky ◽

David Heilman ◽

James Haorah ◽

Marina Zelivyanskaya ◽

Raisa Persidsky ◽

...

Keyword(s):

Endothelial Cells ◽

Tight Junctions ◽

Blood Brain Barrier ◽

Rho Kinase ◽

Dominant Negative ◽

Brain Barrier ◽

Monocyte Migration ◽

Blood Brain ◽

Hiv 1

AbstractThe blood-brain barrier (BBB) is compromised during progressive HIV-1 infection, but how this occurs is incompletely understood. We studied the integrity of tight junctions (TJs) of brain microvascular endothelial cells (BMVECs) in an in vitro BBB system and in human brain tissues with HIV-1 encephalitis (HIVE). A downregulation of TJ proteins, claudin-5 and occludin, paralleled monocyte migration into the brain during HIVE. Because small G proteins (such as Rho) can play a role in BMVEC TJ assembly, an artificial BBB system explored the relationship among TJs, Rho/Rho kinase (RhoK) activation, and transendothelial monocyte migration. Coculture of monocytes with endothelial cells led to Rho activation and phosphorylation of TJ proteins. Rho and RhoK inhibitors blocked migration of infected and uninfected monocytes. The RhoK inhibitor protected BBB integrity and reversed occludin/claudin-5 phosphorylation associated with monocyte migration. BMVEC transfection with a constitutively active mutant of RhoK led to dislocation of occludin from the membrane and loss of BMVEC cell contacts. When dominant-negative RhoK-transfected BMVECs were used in BBB constructs, monocyte migration was reduced by 84%. Thus, loss of TJ integrity was associated with Rho activation caused by monocyte brain migration, suggesting that Rho/RhoK activation in BMVECs could be an underlying cause of BBB impairment during HIVE.

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