Department of Pharmacy, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, Zhejiang, China.
Department of Physiology and Pharmacology, Center for Neuroscience Research, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA.
Fluids Barriers CNS. 2021 Sep 26;18(1):44. doi: 10.1186/s12987-021-00278-9.
Destruction of blood-brain barrier (BBB) is one of the main mechanisms of secondary brain injury following intracerebral hemorrhage (ICH). Frizzled-7 is a key protein expressed on the surface of endothelial cells that controls vascular permeability through the Wnt-canonical pathway involving WNT1-inducible signaling pathway protein 1 (WISPI). This study aimed to investigate the role of Frizzled-7 signaling in BBB preservation after ICH in mice.
Adult CD1 mice were subjected to sham surgery or collagenase-induced ICH. Frizzled-7 activation or knockdown was performed by administration of Clustered Regularly Interspaced Palindromic Repeats (CRISPR) by intracerebroventricular injection at 48 h before ICH induction. WISP1 activation or WISP1 knockdown was performed to evaluate the underlying signaling pathway. Post-ICH assessments included neurobehavior, brain edema, BBB permeability, hemoglobin level, western blot and immunofluorescence.
The brain expressions of Frizzled-7 and WISP1 significantly increased post-ICH. Frizzled-7 was expressed in endothelial cells, astrocytes, and neurons after ICH. Activation of Frizzled-7 significantly improved neurological function, reduced brain water content and attenuated BBB permeability to large molecular weight substances after ICH. Whereas, knockdown of Frizzled-7 worsened neurological function and brain edema after ICH. Activation of Frizzled-7 significantly increased the expressions of Dvl, β-Catenin, WISP1, VE-Cadherin, Claudin-5, ZO-1 and reduced the expression of phospho-β-Catenin. WISP1 knockdown abolished the effects of Frizzled-7 activation on the expressions of VE-Cadherin, Claudin-5 and ZO-1 at 24 h after ICH.
Frizzled-7 activation potentially attenuated BBB permeability and improved neurological deficits after ICH through Dvl/β-Catenin/WISP1 pathway. Frizzled-7 may be a potential target for the development of ICH therapeutic drugs.
血脑屏障（BBB）的破坏是脑出血（ICH）后继发性脑损伤的主要机制之一。卷曲蛋白-7 是一种在血管内皮细胞表面表达的关键蛋白，通过涉及 WNT1 诱导信号通路蛋白 1（WISPI）的 Wnt-经典途径控制血管通透性。本研究旨在探讨卷曲蛋白-7 信号在小鼠 ICH 后 BBB 保护中的作用。
成年 CD1 小鼠接受假手术或胶原酶诱导的 ICH。在 ICH 诱导前 48 小时通过脑室内注射 Clustered Regularly Interspaced Palindromic Repeats（CRISPR）激活或敲低卷曲蛋白-7。激活或敲低 WISP1 以评估潜在的信号通路。ICH 后评估包括神经行为、脑水肿、BBB 通透性、血红蛋白水平、western blot 和免疫荧光。
ICH 后大脑中卷曲蛋白-7 和 WISP1 的表达显著增加。ICH 后卷曲蛋白-7 在内皮细胞、星形胶质细胞和神经元中表达。激活卷曲蛋白-7 可显著改善神经功能，降低 ICH 后脑水含量和 BBB 对大分子量物质的通透性。相反，敲低卷曲蛋白-7 会加重 ICH 后的神经功能障碍和脑水肿。激活卷曲蛋白-7 可显著增加 Dvl、β-连环蛋白、WISP1、VE-钙黏蛋白、Claudin-5、ZO-1 的表达，降低磷酸化β-连环蛋白的表达。ICH 后 24 小时，WISP1 敲低消除了卷曲蛋白-7 激活对 VE-钙黏蛋白、Claudin-5 和 ZO-1 表达的影响。
激活卷曲蛋白-7 通过 Dvl/β-连环蛋白/WISP1 通路减轻 ICH 后 BBB 通透性和改善神经功能缺损。卷曲蛋白-7 可能是开发 ICH 治疗药物的潜在靶点。
