scholarly journals Junctional Protein Regulation by Sphingosine Kinase 2 Contributes to Blood–Brain Barrier Protection in Hypoxic Preconditioning-Induced Cerebral Ischemic Tolerance

2012 ◽  
Vol 32 (6) ◽  
pp. 1014-1023 ◽  
Author(s):  
Bradley K Wacker ◽  
Angela B Freie ◽  
Jennifer L Perfater ◽  
Jeffrey M Gidday
Keyword(s):  
Blood Brain Barrier ◽  
Infarct Volume ◽  
Sphingosine Kinase ◽  
Artery Occlusion ◽  
Ischemic Tolerance ◽  
Hypoxic Preconditioning ◽  
Brain Barrier ◽  
Protein Regulation ◽  
Blood Brain ◽  
Junctional Protein

Protection of the blood–brain barrier (BBB) is correlated with improved outcome in stroke. Sphingosine kinase (SphK)-directed production of sphingosine-1-phosphate, which we previously documented as being vital to preconditioning-induced stroke protection, mediates peripheral vascular integrity via junctional protein regulation. We used a hypoxic preconditioning (HPC) model in adult wild-type and SphK2-null mice to examine the isoform-specific role of SphK2 signaling for ischemic tolerance to transient middle cerebral artery occlusion and attendant BBB protection. Reductions in infarct volume and BBB permeability in HPC-treated mice were completely lost in SphK2-null mice. Hypoxic preconditioning-induced attenuation of postischemic BBB disruption in wild types, evidenced by reduced extravascular immunoglobulin G intensity, suggests direct protection of BBB integrity. Measurement of BBB junctional protein status in response to HPC revealed SphK2-dependent increases in triton-insoluble claudin-5 and VE-cadherin, which may serve to strengthen the BBB before stroke. Postischemic loss of VE-cadherin, occludin, and zona occludens-1 in SphK2-null mice with prior HPC suggests that SphK2-dependent protection of these adherens and tight junction proteins is compulsory for HPC to establish a vasculoprotective phenotype. Further elucidation of the mediators of this endogenous, HPC-activated lipid signaling pathway, and their role in protecting the ischemic BBB, may provide new therapeutic targets for cerebrovascular protection in stroke patients.

scholarly journals Detrimental role of pericyte Nox4 in the acute phase of brain ischemia

2015 ◽  
Vol 36 (6) ◽  
pp. 1143-1154 ◽  
Author(s):  
Ataru Nishimura ◽  
Tetsuro Ago ◽  
Junya Kuroda ◽  
Koichi Arimura ◽  
Masaki Tachibana ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Blood Brain Barrier ◽  
Cerebral Artery ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Brain Barrier ◽  
Blood Brain ◽  
Barrier Breakdown ◽  
Cerebral Artery Occlusion

Pericytes are mural cells abundantly present in cerebral microvessels and play important roles, including the formation and maintenance of the blood–brain barrier. Nox4 is a major source of reactive oxygen species in cardiovascular cells and modulate cellular functions, particularly under pathological conditions. In the present study, we found that the expression of Nox4 was markedly induced in microvascular cells, including pericytes, in peri-infarct areas after middle cerebral artery occlusion stroke models in mice. The upregulation of Nox4 was greater in a permanent middle cerebral artery occlusion model compared with an ischemia/reperfusion transient middle cerebral artery occlusion model. We performed permanent middle cerebral artery occlusion on mice with Nox4 overexpression in pericytes (Tg-Nox4). Infarct volume was significantly greater with enhanced reactive oxygen species production and blood–brain barrier breakdown in peri-infarct areas in Tg-Nox4, compared with littermate controls. In cultured brain pericytes, Nox4 was significantly upregulated by hypoxia and was promptly downregulated by reoxygenation. Phosphorylation of NFκB and production of matrix metalloproteinase 9 were significantly increased in both cultured pericytes overexpressing Nox4 and in peri-infarct areas in Tg-Nox4. Collectively, Nox4 is upregulated in pericytes in peri-infarct areas after acute brain ischemia and may enhance blood–brain barrier breakdown through activation of NFκB and matrix metalloproteinase 9, thereby causing enlargement of infarct volume.

scholarly journals DL-3n-Butylphthalide Improves Blood–Brain Barrier Integrity in Rat After Middle Cerebral Artery Occlusion

2021 ◽  
Vol 14 ◽  
Author(s):  
Muyassar Mamtilahun ◽  
Zhenyu Wei ◽  
Chuan Qin ◽  
Yongting Wang ◽  
Yaohui Tang ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Ischemic Stroke ◽  
Blood Brain Barrier ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Brain Barrier ◽  
Barrier Integrity ◽  
Aqp4 Expression ◽  
Blood Brain ◽  
Blood Brain Barrier Integrity

Objective: DL-3n-butylphthalide (NBP) has beneficial effects in different stages of ischemic stroke. Our previous studies have demonstrated that NBP promoted angiogenesis in the perifocal region of the ischemic brain. However, the molecular mechanism of NBP for blood–brain barrier protection in acute ischemic stroke was unclear. Here, we explored the neuroprotective effects of NBP on blood–brain barrier integrity in the acute phase of ischemic stroke in a rat model.Methods: Adult male Sprague–Dawley rats (n = 82) underwent 2 h of transient middle cerebral artery occlusion and received 90 mg/kg of NBP for 3 days. Brain edema, infarct volume, surface blood flow, and neurological severity score were evaluated. Blood–brain barrier integrity was evaluated by Evans blue leakage and changes in tight junction proteins. We further examined AQP4 and eNOS expression, MMP-9 enzyme activity, and possible signaling pathways for the role of NBP after ischemic stroke.Results: NBP treatment significantly increased eNOS expression and surface blood flow in the brain, reduced brain edema and infarct volume, and improved neurological severity score compared to the control group (p < 0.05). Furthermore, NBP attenuated Evans blue and IgG leakage and increased tight junction protein expression compared to the control after 1 and 3 days of ischemic stroke (p < 0.05). Finally, NBP decreased AQP4 expression, MMP-9 enzyme activity, and increased MAPK expression during acute ischemic stroke.Conclusion: NBP protected blood–brain barrier integrity and attenuated brain injury in the acute phase of ischemic stroke by decreasing AQP4 expression and MMP-9 enzyme activity. The MAPK signaling pathway may be associated in this process.

scholarly journals Systemically Administered Brain-Targeted Nanoparticles Transport Peptides across the Blood—Brain Barrier and Provide Neuroprotection

2015 ◽  
Vol 35 (3) ◽  
pp. 469-475 ◽  
Author(s):  
Muge Yemisci ◽  
Secil Caban ◽  
Yasemin Gursoy-Ozdemir ◽  
Sevda Lule ◽  
Ramon Novoa-Carballal ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Infarct Volume ◽  
Drug Carriers ◽  
Artery Occlusion ◽  
Systemic Administration ◽  
Brain Barrier ◽  
Therapeutic Window ◽  
Targeted Nanoparticles ◽  
Blood Brain ◽  
The Brain

Although growth factors and anti-apoptotic peptides have been shown to be neuroprotective in stroke models, translation of these experimental findings to clinic is hampered by limited penetration of peptides to the brain. Here, we show that a large peptide like the basic fibroblast growth factor (bFGF) and a small peptide inhibitor of caspase-3 (z-DEVD-FMK) can effectively be transported to the brain after systemic administration by incorporating these peptides to brain-targeted nanoparticles (NPs). Chitosan NPs were loaded with peptides and then functionalized by conjugating with antibodies directed against the transferrin receptor-1 on brain endothelia to induce receptor-mediated transcytosis across the blood—brain barrier (BBB). Pre-ischemic systemic administration of bFGF- or z-DEVD-FMK-loaded NPs significantly decreased the infarct volume after 2-hour middle cerebral artery occlusion and 22-hour reperfusion in mice. Co-administration of bFGF- or z-DEVD-FMK-loaded NPs reduced the infarct volume further and provided a 3-hour therapeutic window. bFGF-loaded NPs were histologically detected in the brain parenchyma and also restored ischemia-induced Akt dephosphorylation. The neuroprotection was not observed when receptor-mediated transcytosis was inhibited with imatinib or when bFGF-loaded NPs were not conjugated with the targeting antibody, which enables them to cross the BBB. Nanoparticles targeted to brain are promising drug carriers to transport large as well as small BBB-impermeable therapeutics for neuroprotection against stroke.

Combined Ischemic Preconditioning and Resveratrol Improved Bloodbrain Barrier Breakdown via Hippo/YAP/TAZ Signaling Pathway

2020 ◽  
Vol 18 (9) ◽  
pp. 713-722 ◽  
Author(s):  
Ganji Hong ◽  
Ying Yan ◽  
Yali Zhong ◽  
Jianer Chen ◽  
Fei Tong ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Blood Brain Barrier ◽  
Ischemic Preconditioning ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Cerebral Infarct ◽  
Brain Barrier ◽  
Binding Motif ◽  
Blood Brain ◽  
Barrier Breakdown

Background: Transient Ischemia/Reperfusion (I/R) is the main reason for brain injury and results in disruption of the Blood-Brain Barrier (BBB). It had been reported that BBB injury is one of the main risk factors for early death in patients with cerebral ischemia. Numerous investigations focus on the study of BBB injury which have been carried out. Objective: The objective of this study was to investigate the treatment function of the activation of the Hippo/Yes-Associated Protein (YAP) signaling pathway by combined Ischemic Preconditioning (IPC) and resveratrol (RES) before brain Ischemia/Reperfusion (BI/R) improves Blood-Brain Barrier (BBB) disruption in rats. Methods: Sprague-Dawley (SD) rats were pretreated with 20 mg/kg RES and IPC and then subjected to 2 h of ischemia and 22 h of reperfusion. The cerebral tissues were collected; the cerebral infarct volume was determined; the Evans Blue (EB) level, the brain Water Content (BWC), and apoptosis were assessed; and the expressions of YAP and TAZ were investigated in cerebral tissues. Results: Both IPC and RES preconditioning reduced the cerebral infarct size, improved BBB permeability, lessened apoptosis, and upregulated expressions of YAP and transcriptional co-activator with PDZ-binding motif (TAZ) compared to the Ischemia/Reperfusion (I/R) group, while combined IPC and RES significantly enhanced this action. Conclusion: combined ischemic preconditioning and resveratrol improved blood-brain barrier breakdown via Hippo/YAP/TAZ signaling pathway.

Comparative changes in the blood-brain barrier and cerebral infarction of SHR and WKY rats

2007 ◽  
Vol 292 (5) ◽  
pp. R1881-R1892 ◽  
Author(s):  
Sharon Hom ◽  
Melissa A. Fleegal ◽  
Richard D. Egleton ◽  
Christopher R. Campos ◽  
Brian T. Hawkins ◽  
...  
Keyword(s):  
Cerebral Infarction ◽  
Blood Brain Barrier ◽  
Infarct Volume ◽  
Brain Barrier ◽  
Ion Transporter ◽  
Transporter Proteins ◽  
Wky Rats ◽  
Blood Brain ◽  
Hypertension Development ◽  
The Brain

Hypertension is involved in the exacerbation of stroke. It is unclear how blood-brain barrier (BBB) tight-junction (TJ) and ion transporter proteins critical for maintaining brain homeostasis contribute to cerebral infarction during hypertension development. In the present study, we investigated cerebral infarct volume following permanent 4-h middle cerebral artery occlusion (MCAO) and characterized the expression of BBB TJ and ion transporter proteins in brain microvessels of spontaneously hypertensive rats (SHR) compared with age-matched Wistar-Kyoto (WKY) rats at 5 wk (prehypertension), 10 wk (early-stage hypertension), and 15 wk (later-stage hypertension) of age. Hypertensive SHR show increased infarct volume following MCAO compared with WKY control rats. BBB TJ and ion transporter proteins, known to contribute to edema and fluid volume changes in the brain, show differential protein expression patterns during hypertension development. Western blot analysis of TJ protein zonula occludens-2 (ZO-2) showed decreased expression, while ion transporter, Na+/H+ exchanger 1 (NHE-1), was markedly increased in hypertensive SHR. Expression of TJ proteins ZO-1, occludin, actin, claudin-5, and Na+-K+-2Cl− cotransporter remain unaffected in SHR compared with control. Selective inhibition of NHE-1 using dimethylamiloride significantly attenuated ischemia-induced infarct volume in hypertensive SHR following MCAO, suggesting a novel role for NHE-1 in the brain in the regulation of ischemia-induced infarct volume in SHR.

Abstract TP80: Panaxatriol Saponins Attenuates Blood-brain Barrier Disruption and Promotes Angiogenesis After Ischemic Stroke in Rats

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Hui Yang ◽  
Zhen Hui ◽  
Du Juan Sha ◽  
Yun Xu
Keyword(s):  
Ischemic Stroke ◽  
Blood Brain Barrier ◽  
Cerebral Perfusion ◽  
Infarct Volume ◽  
Immunofluorescence Staining ◽  
Brain Barrier ◽  
Shh Pathway ◽  
Blood Brain Barrier Disruption ◽  
Blood Brain ◽  
Brain Barrier Disruption

Background: The induction of angiogenesis and maintain the integrity of the blood brain barrier (BBB) after stroke may enhance neurorestorative processes. Panaxatriol Saponins (PTS), extracted from traditional Chinese herb Panaxnotoginseng, could noticeably prevent BBB disruption and promote angiogenesis in rodent stroke model. Methods: Middle cerebral artery occlusion (MCAO) model were applied to mimic acute stroke in vivo. Ischemic infarct volume and neurological functions were evaluated through 2,3,5-triphenyltetrazolium chloride (TTC) staining and Longa Scores (LS) respectively. The micro-PET scan was adopted to assess cerebral perfusion; evans blue extravasation assay was used to test BBB permeability; real time PCR and Western blot were used to evaluate the level of vascular growth factors, pro-inflammation factors, the components of Sonic hedgehog (Shh) pathway and NF-κB pathway. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the levels of pro-inflammation factors in the brain. The capillaries density in ischemic penumbra and tight junction in BBB were measured by immunofluorescence staining. Results: PTS treatment improved neurological function and reduced infarct volume in MCAO-rats. The result of micro-PET scan indicated that PTS could significantly enhance cerebral perfusion after MCAO operation. Treatment of PTS significantly attenuated BBB destruction. PTS could significantly increase the VEGF, Ang-1, VEGFR-2, Tie-2, CD31 and α-SMA mRNA expression at 3 d and 7 d after MCAO compared to vehicle group. Moreover, the expression levels of inflammation factors were decreased after PTS treatment. The co-immunofluorescence staining of α-SMA and Brdu with CD31 respectively showed that PTS promotes angiogenesis and endothelial cell proliferation after MCAO. Meanwhile, co-immunofluorescence staining of Claudin-5, Occludin and ZO-1 with CD31 respectively showed that PTS could protect tight junction from ischemia/reperfusion injury. PTS could also activate Shh pathway and inhibited NF-κB pathway. Conclusions: PTS alleviated ischemic stroke injury through attenuates blood-brain barrier disruption and promotes angiogenesis. PTS could be a potential medication for combating ischemic brain injury.

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