重组 Slit2 通过 Robo1-srGAP1 通路抑制神经炎症和 Cdc42 介导的外周免疫细胞向脑实质出血大鼠模型中的浸润。
Recombinant Slit2 suppresses neuroinflammation and Cdc42-mediated brain infiltration of peripheral immune cells via Robo1-srGAP1 pathway in a rat model of germinal matrix hemorrhage.
机构信息
Department of Pediatrics, Army Medical Center, Army Medical University, 10 Changjiang Access Rd, Yuzhong District, Chongqing, 400042, China.
Women and Children's Hospital of Chongqing Medical University, 120 Longshan Access Rd, Yubei District, Chongqing, 400010, China.
出版信息
J Neuroinflammation. 2023 Oct 29;20(1):249. doi: 10.1186/s12974-023-02935-2.
BACKGROUND
Germinal matrix hemorrhage (GMH) is a devastating neonatal stroke, in which neuroinflammation is a critical pathological contributor. Slit2, a secreted extracellular matrix protein, plays a repulsive role in axon guidance and leukocyte chemotaxis via the roundabout1 (Robo1) receptor. This study aimed to explore effects of recombinant Slit2 on neuroinflammation and the underlying mechanism in a rat model of GMH.
METHODS
GMH was induced by stereotactically infusing 0.3 U of bacterial collagenase into the germinal matrix of 7-day-old Sprague Dawley rats. Recombinant Slit2 or its vehicle was administered intranasally at 1 h after GMH and daily for 3 consecutive days. A decoy receptor recombinant Robo1 was co-administered with recombinant Slit2 after GMH. Slit2 siRNA, srGAP1 siRNA or the scrambled sequences were administered intracerebroventricularly 24 h before GMH. Neurobehavior, brain water content, Western blotting, immunofluorescence staining and Cdc42 activity assays were performed.
RESULTS
The endogenous brain Slit2 and Robo1 expressions were increased after GMH. Robo1 was expressed on neuron, astrocytes and infiltrated peripheral immune cells in the brain. Endogenous Slit2 knockdown by Slit2 siRNA exacerbated brain edema and neurological deficits following GMH. Recombinant Slit2 (rSlit2) reduced neurological deficits, proinflammatory cytokines, intercellular adhesion molecules, peripheral immune cell markers, neuronal apoptosis and Cdc42 activity in the brain tissue after GMH. The anti-neuroinflammation effects were reversed by recombinant Robo1 co-administration or srGAP1 siRNA.
CONCLUSIONS
Recombinant Slit2 reduced neuroinflammation and neuron apoptosis after GMH. Its anti-neuroinflammation effects by suppressing onCdc42-mediated brain peripheral immune cells infiltration was at least in part via Robo1-srGAP1 pathway. These results imply that recombinant Slit2 may have potentials as a therapeutic option for neonatal brain injuries.
背景
脑室内出血（GMH）是一种破坏性的新生儿中风，其中神经炎症是一个关键的病理贡献者。Slit2 是一种分泌型细胞外基质蛋白，通过 Roundabout1（Robo1）受体在轴突导向和白细胞趋化中发挥排斥作用。本研究旨在探讨重组 Slit2 对 GMH 大鼠模型中神经炎症的影响及其潜在机制。
方法
7 日龄 Sprague Dawley 大鼠立体定向脑室内注射 0.3U 细菌胶原酶诱导 GMH。GMH 后 1 小时给予重组 Slit2 或其载体，并连续 3 天每天给药。GMH 后给予重组 Slit2 与诱饵受体重组 Robo1 共给药。GMH 前 24 小时给予 Slit2 siRNA、srGAP1 siRNA 或乱序序列。进行神经行为、脑水含量、Western 印迹、免疫荧光染色和 Cdc42 活性测定。
结果
GMH 后内源性脑 Slit2 和 Robo1 表达增加。Robo1 在神经元、星形胶质细胞和浸润的外周免疫细胞上表达。GMH 后 Slit2 siRNA 下调内源性 Slit2 加重脑水肿和神经功能缺损。GMH 后给予重组 Slit2（rSlit2）可减轻脑组织神经炎症、促炎细胞因子、细胞间黏附分子、外周免疫细胞标志物、神经元凋亡和 Cdc42 活性。用重组 Robo1 共给药或 srGAP1 siRNA 逆转了抗神经炎症作用。
结论
重组 Slit2 可减轻 GMH 后的神经炎症和神经元凋亡。其通过抑制 onCdc42 介导的脑外周免疫细胞浸润来发挥抗炎作用，至少部分是通过 Robo1-srGAP1 途径。这些结果表明，重组 Slit2 可能是新生儿脑损伤的一种治疗选择。
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