Induction of Blood Brain Barrier Tight Junction Protein Alterations by CD8 T Cells

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.

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Cocaine-mediated Alteration in Tight Junction Protein Expression and Modulation of CCL2/CCR2 Axis Across the Blood-Brain Barrier: Implications for HIV-Dementia

Journal of Neuroimmune Pharmacology ◽

10.1007/s11481-007-9091-1 ◽

2007 ◽

Vol 3 (1) ◽

pp. 52-56 ◽

Cited By ~ 47

Author(s):

Navneet K. Dhillon ◽

Fuwang Peng ◽

Sirosh Bokhari ◽

Shannon Callen ◽

Sun-Hye Shin ◽

...

Keyword(s):

Protein Expression ◽

Tight Junction ◽

Blood Brain Barrier ◽

Tight Junction Protein ◽

Brain Barrier ◽

Hiv Dementia ◽

Tight Junction Protein Expression ◽

Blood Brain ◽

Junction Protein

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Isoflurane anesthesia results in reversible ultrastructure and occludin tight junction protein expression changes in hippocampal blood–brain barrier in aged rats

Neuroscience Letters ◽

10.1016/j.neulet.2014.12.018 ◽

2015 ◽

Vol 587 ◽

pp. 51-56 ◽

Cited By ~ 26

Author(s):

Yiyun Cao ◽

Cheng Ni ◽

Zhengqian Li ◽

Lunxu Li ◽

Yajie Liu ◽

...

Keyword(s):

Protein Expression ◽

Tight Junction ◽

Blood Brain Barrier ◽

Tight Junction Protein ◽

Brain Barrier ◽

Aged Rats ◽

Isoflurane Anesthesia ◽

Tight Junction Protein Expression ◽

Blood Brain ◽

Junction Protein

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EMP-induced alterations of tight junction protein expression and disruption of the blood–brain barrier

Toxicology Letters ◽

10.1016/j.toxlet.2010.04.011 ◽

2010 ◽

Vol 196 (3) ◽

pp. 154-160 ◽

Cited By ~ 31

Author(s):

Gui-Rong Ding ◽

Lian-Bo Qiu ◽

Xiao-Wu Wang ◽

Kang-Chu Li ◽

Yong-Chun Zhou ◽

...

Keyword(s):

Protein Expression ◽

Tight Junction ◽

Blood Brain Barrier ◽

Tight Junction Protein ◽

Brain Barrier ◽

Tight Junction Protein Expression ◽

Blood Brain ◽

Junction Protein

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RhoA/ROCK-2 Pathway Inhibition and Tight Junction Protein Upregulation by Catalpol Suppresses Lipopolysaccaride-Induced Disruption of Blood-Brain Barrier Permeability

Molecules ◽

10.3390/molecules23092371 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2371 ◽

Cited By ~ 14

Author(s):

Shan Feng ◽

Li Zou ◽

Hongjin Wang ◽

Ran He ◽

Ke Liu ◽

...

Keyword(s):

Tight Junction ◽

Signaling Pathway ◽

Tight Junctions ◽

Blood Brain Barrier ◽

Tight Junction Protein ◽

Brain Barrier ◽

Endothelin 1 ◽

Blood Brain ◽

Junction Protein ◽

Bbb Permeability

Lipopolysaccaride (LPS) directly or indirectly injures brain microvascular endothelial cells (BMECs) and damages the intercellular tight junction that gives rise to altered blood-brain barrier (BBB) permeability. Catalpol plays a protective role in LPS-induced injury, but whether catalpol protects against LPS-caused damage of BBB permeability and the underlying mechanism remain to be delineated. Prophylactic protection with catalpol (5 mg/kg, i.v.) consecutively for three days reversed the LPS-induced damage of BBB by decreased Evans Blue (EB) leakage and restored tight junctions in C57 mice. Besides, catalpol co-administrated with LPS increased BMECs survival, decreased their endothelin-1, TNF-Α and IL-6 secretion, improved transmembrane electrical resistance in a time-dependent manner, and in addition increased the fluorescein sodium permeability coefficient of BMECs. Also, transmission electron microscopy showed catalpol protective effects on tight junctions. Fluorescence staining displayed that catalpol reversed the rearrangement of the cytoskeleton protein F-actin and upregulated the tight junction protein of claudin-5 and ZO-1, which have been further demonstrated by the mRNA and protein expression levels of ZO-1, ZO-2, ZO-3, claudin-5, and occludin. Moreover, catalpol concurrently downregulated the mRNA and protein levels of RhoA, and ROCK2, the critical proteins in the RhoA/ROCK2 signaling pathway. This study thus indicated that catalpol, via inhibition of the RhoA/ROCK2 signaling pathway, reverses the disaggregation of cytoskeleton actin in BMECs and prevents down-regulation of junctional proteins, such as claudin-5, occludin, and ZO-1, and decreases endothelin-1 and inflammatory cytokine secretion, eventually alleviating the increase in LPS-induced BBB permeability.

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Abstract TP256: Mouse Model of Uremic Cerebral Microbleeds

Stroke ◽

10.1161/str.47.suppl_1.tp256 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Wei Ling Lau ◽

Mary Tarbiat-Boldaji ◽

Hayley Smalls ◽

Ane Nunes ◽

Javad Savoj ◽

...

Keyword(s):

Mouse Model ◽

Tight Junction ◽

Blood Brain Barrier ◽

Cerebral Microbleeds ◽

Brain Barrier ◽

Barrier Integrity ◽

Blood Brain ◽

Increased Risk ◽

Junction Protein ◽

Blood Brain Barrier Integrity

Introduction: Cerebral microbleeds are more common in chronic kidney disease (CKD) and dialysis patients compared to the general population. Diminished kidney function alone appears to be a risk factor for microbleeds, independent of age and hypertension. Microbleed burden in CKD patients is associated with increased risk of future hemorrhagic stroke and with cognitive dysfunction. The mechanisms that drive uremic microbleed formation are unclear. Hypothesis: We hypothesized that CKD mice are predisposed to develop cerebral microhemorrhages (the pathologic substrate of microbleeds), and that a standardized inflammatory stimulus (lipopolysaccharide, LPS) will amplify microhemorrhage burden in CKD mice compared to non-CKD controls (CTL). We also hypothesized that uremia induces depletion of tight junction proteins, altering blood-brain barrier integrity and representing a potential mechanism of microbleed formation. Methods: Animal groups included CTL (n=3), CKD (n=3), CTL+LPS (n=5) and CKD+LPS (n=5). CKD induction in male C57BL/6 mice was achieved via nephrotoxic adenine diet x18 days. Two weeks following CKD induction, CKD and control mice were treated with LPS 1 mg/kg i.p. dosed at 0, 6 and 24 hours. Brains were harvested one week after LPS injections and 40-micron sections were stained using Prussian blue to identify microhemorrhages. Immunohistochemistry was performed for the blood-brain barrier tight junction protein claudin-5. Results: CKD mice had significantly elevated blood urea nitrogen, and tubulointerstitial fibrosis was present on kidney histology. Total number of microhemorrhages per brain was 2.3±1.5 (mean ± standard error of the mean) for CTL mice, 8.3±1.5 for CKD mice, 23.2±4.2 for CTL+LPS mice, and 27.6±6.2 for CKD+LPS mice (p<0.05 for CKD+LPS vs. CTL). Immunostaining showed decreased claudin-5 expression in CKD mice compared to CTL. Conclusions: We have generated a mouse model that will facilitate future mechanistic studies in the field of uremic microbleeds. Our initial findings suggest that CKD alters blood-brain barrier integrity and that inflammation amplifies development of microbleeds in CKD.

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