Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This stud...Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[（2R）-2-（hydroxamidocarbonylmethyl）-4-methylpenthanoyl]-L- tryptophan methylamide （GM6001） showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier （tight junction proteins） is of importance.展开更多
Background:The increased permeability of the blood-brain barrier (BBB) induced by ischemia/hypoxia is generally correlated with alteration of tight junctions (TJs). DL-3-n-butylphthalide (NBP) has been shown to exert ...Background:The increased permeability of the blood-brain barrier (BBB) induced by ischemia/hypoxia is generally correlated with alteration of tight junctions (TJs). DL-3-n-butylphthalide (NBP) has been shown to exert neuroprotective effects after ischemic injury. However, few studies have assessed the correlation between NBP and TJs. This study aimed to investigate the potential effect of NBP on the TJ proteins claudin-5, zonula occludens-1 (ZO-1), and occludin during brain ischemia. Methods: A chronic cerebral hypoperfusion (CCH) Sprague-Dawley rat model was established, and NBP (20, 40, or 80 mg/kg, gavage, once a day) treatment was performed for 14 days. NBP (0.1 or 1.0μmol/L) pre-treatment was applied to an in vitro hypoxia microvascular endothelial cell model (1%〇2, 24 h). BBB permeability was assessed by performing the Evans blue assay. The expressions and localization of claudin-5, ZO-1, occludin, phosphorylated/total protein kinase B (p-Akt/Akt), phosphorylated/total glycogen synthase kinase 3p (GSK-3(3)/GSK-3p, and (3-catenin/p-actin were evaluated by Western blotting or immunofluorescence. Reactive oxygen species (ROS) generation was measured by flow cytometry analysis. TJ ultrastructure was observed by transmission electron microscopy. Results: In CCH rats, treatment with 40 and 80 mg/kg NBP decreased the Evans blue content in brain tissue (9.0 ± 0.9 (μg/g vs. 12.3 ± 1.9 (μg/g, P = 0.005;6.7 ± 0.6 μg/g vs. 12.3 ± 1.9μg/g, P < 0.01), increased the expression of claudin-5 (0.79 ± 0.08 mvs. 0.41 ± 0.06, P < 0.01;0.07 ± 0 .0 7 vs. 0.41 ± 0 .0 6 , P < 0 .61 ), and elevated the ZO-1 protein level (P < 0.05) in brain microvascular segments in a dose-dependent manner in comparison with the corresponding values in the model group. There was no significant difference in occludin expression (P > 0.05). In the hypoxia cell model, NBP pre-treatment improved TJ ultrastructure, decreased intracellular ROS level, and increased the expression of claudin-5 (P < 0.01) and ZO-1 (P < 0.01) in comparison with the corresponding values in the hypoxia group. NBP treatment also elevated the relative expression levels of p-Akt/Akt, p-GSK-3p/GSK-3β, and β-catenin/β-actin in comparison with the corresponding values in the hypoxia group (all P < 0 .0 5 ). Conclusion: NBP improves the barrier function of BBB against ischemic injury by upregulating the expression of TJ proteins, possibly by reducing oxidative stress and activating the Akt/GSK-3β/β-catenin signaling pathway.展开更多
Aberrant tumor blood vessels are prone to propel the malignant progression of tumors,and targeting abnormal metabolism of tumor endothelial cells emerges as a promising option to achieve vascular normalization and ant...Aberrant tumor blood vessels are prone to propel the malignant progression of tumors,and targeting abnormal metabolism of tumor endothelial cells emerges as a promising option to achieve vascular normalization and antagonize tumor progression.Herein,we demonstrated that salvianic acid A(SAA)played a pivotal role in contributing to vascular normalization in the tumor-bearing mice,thereby improving delivery and effectiveness of the chemotherapeutic agent.SAA was capable of inhibiting glycolysis and strengthening endothelial junctions in the human umbilical vein endothelial cells(HUVECs)exposed to hypoxia.Mechanistically,SAA was inclined to directly bind to the glycolytic enzyme PKM2,leading to a dramatic decrease in endothelial glycolysis.More importantly,SAA improved the endothelial integrity via activating theβ-Catenin/Claudin-5 signaling axis in a PKM2-dependent manner.Our findings suggest that SAA may serve as a potent agent for inducing tumor vascular normalization.展开更多
文摘Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[（2R）-2-（hydroxamidocarbonylmethyl）-4-methylpenthanoyl]-L- tryptophan methylamide （GM6001） showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier （tight junction proteins） is of importance.
文摘Background:The increased permeability of the blood-brain barrier (BBB) induced by ischemia/hypoxia is generally correlated with alteration of tight junctions (TJs). DL-3-n-butylphthalide (NBP) has been shown to exert neuroprotective effects after ischemic injury. However, few studies have assessed the correlation between NBP and TJs. This study aimed to investigate the potential effect of NBP on the TJ proteins claudin-5, zonula occludens-1 (ZO-1), and occludin during brain ischemia. Methods: A chronic cerebral hypoperfusion (CCH) Sprague-Dawley rat model was established, and NBP (20, 40, or 80 mg/kg, gavage, once a day) treatment was performed for 14 days. NBP (0.1 or 1.0μmol/L) pre-treatment was applied to an in vitro hypoxia microvascular endothelial cell model (1%〇2, 24 h). BBB permeability was assessed by performing the Evans blue assay. The expressions and localization of claudin-5, ZO-1, occludin, phosphorylated/total protein kinase B (p-Akt/Akt), phosphorylated/total glycogen synthase kinase 3p (GSK-3(3)/GSK-3p, and (3-catenin/p-actin were evaluated by Western blotting or immunofluorescence. Reactive oxygen species (ROS) generation was measured by flow cytometry analysis. TJ ultrastructure was observed by transmission electron microscopy. Results: In CCH rats, treatment with 40 and 80 mg/kg NBP decreased the Evans blue content in brain tissue (9.0 ± 0.9 (μg/g vs. 12.3 ± 1.9 (μg/g, P = 0.005;6.7 ± 0.6 μg/g vs. 12.3 ± 1.9μg/g, P < 0.01), increased the expression of claudin-5 (0.79 ± 0.08 mvs. 0.41 ± 0.06, P < 0.01;0.07 ± 0 .0 7 vs. 0.41 ± 0 .0 6 , P < 0 .61 ), and elevated the ZO-1 protein level (P < 0.05) in brain microvascular segments in a dose-dependent manner in comparison with the corresponding values in the model group. There was no significant difference in occludin expression (P > 0.05). In the hypoxia cell model, NBP pre-treatment improved TJ ultrastructure, decreased intracellular ROS level, and increased the expression of claudin-5 (P < 0.01) and ZO-1 (P < 0.01) in comparison with the corresponding values in the hypoxia group. NBP treatment also elevated the relative expression levels of p-Akt/Akt, p-GSK-3p/GSK-3β, and β-catenin/β-actin in comparison with the corresponding values in the hypoxia group (all P < 0 .0 5 ). Conclusion: NBP improves the barrier function of BBB against ischemic injury by upregulating the expression of TJ proteins, possibly by reducing oxidative stress and activating the Akt/GSK-3β/β-catenin signaling pathway.
基金This work was financially supported by the projects of National Natural Science Foundation of China(82003991,82101844,and 82304953)Natural Science Foundation of Jiangsu Province(BK20230744,China)+1 种基金Jiangsu Specially Appointed Professorship Foundation(013038021001,China)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22-2045 and KYCX23-2038,China).
文摘Aberrant tumor blood vessels are prone to propel the malignant progression of tumors,and targeting abnormal metabolism of tumor endothelial cells emerges as a promising option to achieve vascular normalization and antagonize tumor progression.Herein,we demonstrated that salvianic acid A(SAA)played a pivotal role in contributing to vascular normalization in the tumor-bearing mice,thereby improving delivery and effectiveness of the chemotherapeutic agent.SAA was capable of inhibiting glycolysis and strengthening endothelial junctions in the human umbilical vein endothelial cells(HUVECs)exposed to hypoxia.Mechanistically,SAA was inclined to directly bind to the glycolytic enzyme PKM2,leading to a dramatic decrease in endothelial glycolysis.More importantly,SAA improved the endothelial integrity via activating theβ-Catenin/Claudin-5 signaling axis in a PKM2-dependent manner.Our findings suggest that SAA may serve as a potent agent for inducing tumor vascular normalization.
