Simultaneous activation of several second messengers in hypoxia‐induced hyperpermeability of brain derived endothelial cells

Fischer, Silvia; Wiesnet, Marion; Marti, Hugo H.; Renz, D.; Schäper, Wolfgang

doi:10.1002/jcp.10417

Cited by 93 publications

(66 citation statements)

References 68 publications

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“…This idea is supported by a study (20) that showed that PKC mediates BBB function by altering ICAM and fluid phase endocytosis in tumor necrosis factor ␣-treated endothelial cells. It is also supported by a study (24) that demonstrated a minimal role for PKC in H-induced BBB permeability and TJ alterations induced by H and VEGF.…”

Section: Discussionmentioning

confidence: 56%

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Fleegal

Hom

Borg

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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-The blood-brain barrier (BBB) is a metabolic and physiological barrier important for maintaining brain homeostasis. The aim of this study was to determine the role of PKC activation in BBB paracellular permeability changes induced by hypoxia and posthypoxic reoxygenation using in vitro and in vivo BBB models. In rat brain microvessel endothelial cells (RMECs) exposed to hypoxia (1% O 2-99% N2; 24 h), a significant increase in total PKC activity was observed, and this was reduced by posthypoxic reoxygenation (95% room air-5% CO 2) for 2 h. The expression of PKC-␤II, PKC-␥, PKC-, PKC-, and PKC-also increased following hypoxia (1% O 2-99% N2; 24 h), and these protein levels remained elevated following posthypoxic reoxygenation (95% room air-5% CO 2; 2 h). Increases in the expression of PKC-⑀ and PKC-were also observed following posthypoxic reoxygenation (95% room air-5% CO 2; 2 h). Moreover, inhibition of PKC with chelerythrine chloride (10 M) attenuated the hypoxiainduced increases in [ 14 C]sucrose permeability. Similar to what was observed in RMECs, total PKC activity was also stimulated in cerebral microvessels isolated from rats exposed to hypoxia (6% O 2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min). In contrast, hypoxia (6% O2-94% N2; 1 h) and posthypoxic reoxygenation (room air; 10 min) significantly increased the expression levels of only PKC-␥ and PKC-in the in vivo hypoxia model. These data demonstrate that hypoxia-induced BBB paracellular permeability changes occur via a PKC-dependent mechanism, possibly by differentially regulating the protein expression of the 11 PKC isozymes. protein kinase C; paracellular; neurovascular unit; rat THE BLOOD-BRAIN BARRIER (BBB) is a metabolic and physiological barrier important for maintaining cerebral homeostasis. Brain microvessels that form the BBB are lined with specialized endothelial cells surrounded by pericytes, astroglial processes, and the extracellular matrix. Compared with the peripheral microvasculature, cerebral microvessels are highly specialized because they lack vesicular transport and fenestrations while having a high level of metabolic activity. This lack of fenestrations is due to the presence of tight junctions (TJ) and adherens junctions, which restrict paracellular movement of molecules across the BBB (29,31,40).Stroke is a leading cause of death and disability in the United States (3). It has been demonstrated that the BBB is compromised during stroke (29). The effects of stroke on the cerebral vasculature significantly contribute to the brain damage caused by stroke. It has been determined that the lack of oxygen (hypoxia, H) followed by reperfusion (posthypoxic reoxygenation, H/R) during stroke contributes to both neuronal and vascular damage. Both H and H/R cause increases in cerebrovascular permeability with concomitant increases in vasogenic cerebral edema (1,36,47).Previous studies (36, 47) have demonstrated that H and H/R cause changes in paracellular permeability to [ 14 C]sucrose in cerebral vascular endothelial cells....

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Section: Discussionmentioning

confidence: 56%

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Fleegal

Hom

Borg

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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“…Fischer et al believed that the hyperpermeability induced by H 2 O 2 was caused by activation of p44/42 mitogen activated protein (MAP) kinase through changing the localization of tight junction proteins. 18) In another study of colonic epithelium, it was found that protein kinase C, not MAPK, is involved in the regulation of ZO-1. Meanwhile, Sheth et al found that the PI3K signaling pathway is involved in oxidative stress-induced disruption of tight junctions.…”

Section: Discussionmentioning

confidence: 99%

Telmisartan Increases the Permeability of Endothelial Cells through Zonula Occludens-1

Bian

Chen

2009

Biological & Pharmaceutical Bulletin

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Angiotensin receptor-1 blockers (ARBs) have been used for the treatment of atherosclerosis. Tight junctions are very important in the regulation of cellular permeability which may have a profound role in atherosclerosis. The relationship between them is unresolved. The expression and distribution of zonula occludens-1 (ZO-1), the permeability of cultured endothelial cells, and the activity of phosphatidylinositol 3-kinase (PI3K) were all detected with various methods after cultured endothelial cells were exposed to valsartan and the special ARB telmisartan or combined with PI3K inhibitor wortmannin or the peroxisome proliferator-activated receptor gamma antagonist GW9662. We found that telmisartan but not valsartan downregulated ZO-1 mRNA and protein levels, disrupted the distribution of ZO-1 in cultured endothelial cells, and increased the permeability of endothelial cells in a dose-dependent manner. When the PI3K inhibitor wortmannin was used, the effect induced by telmisartan was at least partly reversed. The role of the PI3K signaling pathway was further confirmed in the PI3K activity assay. GW9662 significantly blocked telmisartan-induced ZO-1 changes. Our results suggest that telmisartan disrupts the continuous pericellular distribution of ZO-1, downregulates the expression of ZO-1 in endothelial cells, and increases the permeability of endothelial cells at least partly through PI3K and the peroxisome proliferator-activated receptor gamma-dependent pathway.

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“…Our data indicated that VASP levels increased in the membrane and cytoskeletal fractions after 1 h of hypoxia, supporting the idea that there is an early dynamic change in the actin cytoskeleton. This mobilization is likely to be mediated through multiple pathways, including PKG (15,63), MLCK (34), and RhoA/ ROCK (27).…”

Section: Discussionmentioning

confidence: 99%

TRPC-mediated actin-myosin contraction is critical for BBB disruption following hypoxic stress

Hicks

O’Neil

Dubinsky

et al. 2010

American Journal of Physiology-Cell Physiology

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Hicks K, O'Neil RG, Dubinsky WS, Brown RC. TRPC-mediated actin-myosin contraction is critical for BBB disruption following hypoxic stress. Am J Physiol Cell Physiol 298: C1583-C1593, 2010. First published February 17, 2010 doi:10.1152/ajpcell.00458.2009.-Hypoxia-induced disruption of the blood-brain barrier (BBB) is the result of many different mechanisms, including alterations to the cytoskeleton. In this study, we identified actin-binding proteins involved in cytoskeletal dynamics with quantitative proteomics and assessed changes in subcellular localization of two proteins involved in actin polymerization [vasodilator-stimulated phosphoprotein (VASP)] and cytoskeleton-plasma membrane cross-linking (moesin). We found significant redistribution of both VASP and moesin to the cytoskeletal and membrane fractions of BBB endothelial cells after 1-h hypoxic stress. We also investigated activation of actin-myosin contraction through assessment of phosphorylated myosin light chain (pMLC) with confocal microscopy. Hypoxia caused a rapid and transient increase in pMLC. Blocking MLC phosphorylation through inhibition of myosin light chain kinase (MLCK) with ML-7 prevented hypoxiainduced BBB disruption and relocalization of the tight junction protein ZO-1. Finally, we implicate the transient receptor potential (TRP)C family of channels in mediating these events since blockade of TRPC channels and the associated calcium influx with SKF-96365 prevents hypoxia-induced permeability changes and the phosphorylation of MLC needed for actin-myosin contraction. These data suggest that hypoxic stress triggers alterations to cytoskeletal structure that contribute to BBB disruption and that calcium influx through TRPC channels contributes to these events. cation channels; endothelial cell; stroke; blood-brain barrier; calcium; transient receptor potential C channels BREAKDOWN of the blood-brain barrier (BBB) contributes to edema formation, infarct size, and brain damage following ischemic stroke (3,10,36,39). There are many factors contributing to BBB disruption in ischemia, including generation of oxygen radicals (24, 56, 58), nitric oxide (22, 42), production of vascular endothelial growth factor (67, 69), and changes in intracellular calcium (5,26,35). Under normal conditions, the integrity of the BBB is maintained by tight junction complexes between adjacent brain capillary endothelial cells (2). Changes in BBB permeability are correlated with changes in tight junction structure (33,45,51,59). After hypoxia, this increased permeability is associated with disruptions in the subcellular localization of the tight junction proteins zonula occludens-1 (ZO-1) (43) and occludin (5).A major contributing factor to disruption of the BBB after hypoxia is contraction of the actin-myosin cytoskeleton (23). A recent study demonstrated that inhibition of actin-myosin contraction protected the BBB after hypoxic stress (34); hypoxiainduced BBB disruption was prevented by inhibition of myosin light chain kinase (MLCK), by inhibition of NADPH-oxida...

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Simultaneous activation of several second messengers in hypoxia‐induced hyperpermeability of brain derived endothelial cells

Cited by 93 publications

References 68 publications

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Activation of PKC modulates blood-brain barrier endothelial cell permeability changes induced by hypoxia and posthypoxic reoxygenation

Telmisartan Increases the Permeability of Endothelial Cells through Zonula Occludens-1

TRPC-mediated actin-myosin contraction is critical for BBB disruption following hypoxic stress

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