BACKGROUND Multiple sclerosis (MS) is an autoimmune disease which results from the invasion of the brain by activated immune cells across the endothelial cells (ECs) of the blood-brain barrier (BBB), due to loss of immune self-tolerance. Many reports define the metabolic profile of immune cells in MS, however little is known about the metabolism of the BBB ECs during the disease. We aim to determine whether circulating factors in MS induce metabolic alterations of the BBB ECs compared to a healthy state, which can be linked with disruption of BBB integrity and subsequent immune cell extravasation. METHODS AND RESULTS In this report, we used an in vitro model to study the effect of sera from naïve-to-treatment, relapsing-remitting MS (RRMS) patients on the human brain microvascular endothelium, comparing effects to age/sex-matched healthy donor (HD) sera. Our data show that RRMS serum components affect brain endothelial cells by impairing intercellular tightness through the down-modulation of occludin and VE-cadherin, and facilitating immune cell extravasation through upregulation of intercellular adhesion molecules (ICAM-1) and P-glycoprotein (P-gp). At a metabolic level, the treatment of the endothelial cells with RRMS sera reduced their glycolytic activity (measured through the extracellular acidification rate-ECAR) and oxygen consumption rate (oxidative phosphorylation rate-OCR). Such changes were associated with the down-modulation of endothelial glucose transporter 1 (GLUT-1) expression and by altered mitochondrial membrane potential. Higher level of reactive oxygen species released from the endothelial cells treated with RRMS sera indicate a pro-inflammatory status of the cells together with the higher expression of ICAM-1, endothelial cell cytoskeleton perturbation (stress fibres) as well as disruption of the cytoskeleton signal transduction MSK1/2 and β-catenin phosphorylation. CONCLUSIONS Our data suggest that circulating factors present in RRMS patient serum induce physiological and biochemical alterations to the BBB, namely reducing expression of essential tightness regulators, as well as reduced engagement of glycolysis and alteration of mitochondrial potential. As these last changes have been linked with alterations in nutrient usage and metabolic function in immune cells; we propose that the BBB endothelium of MS patients may similarly undergo metabolic dysregulation, leading to enhanced permeability and increased disease susceptibility.

中文翻译：

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多发性硬化症患者血清对血脑屏障内皮细胞的免疫代谢影响。

背景技术多发性硬化症（MS）是一种自身免疫性疾病，由于免疫自我耐受性丧失，激活的免疫细胞穿过血脑屏障（BBB）的内皮细胞（EC）侵入大脑而引起。许多报告定义了多发性硬化症中免疫细胞的代谢特征，但对于疾病期间 BBB EC 的代谢知之甚少。我们的目的是确定与健康状态相比，MS 中的循环因子是否会引起 BBB EC 的代谢改变，这可能与 BBB 完整性破坏和随后的免疫细胞外渗有关。方法和结果在本报告中，我们使用体外模型来研究初治复发缓解型多发性硬化症 (RRMS) 患者的血清对人脑微血管内皮的影响，并将其与年龄/性别匹配的健康患者的影响进行比较供体 (HD) 血清。我们的数据表明，RRMS 血清成分通过下调 occludin 和 VE-cadherin 损害细胞间的紧密度，并通过上调细胞间粘附分子 (ICAM-1) 和 P-糖蛋白 (P-) 促进免疫细胞外渗来影响脑内皮细胞。全科医生）。在代谢水平上，用RRMS血清处理内皮细胞降低了其糖酵解活性（通过细胞外酸化率-ECAR测量）和耗氧率（氧化磷酸化率-OCR）。这种变化与内皮葡萄糖转运蛋白 1 (GLUT-1) 表达的下调和线粒体膜电位的改变有关。用 RRMS 血清处理的内皮细胞释放的活性氧水平较高，表明细胞处于促炎状态，同时 ICAM-1 表达较高，内皮细胞细胞骨架扰动（应激纤维）以及细胞骨架信号破坏转导 MSK1/2 和 β-连环蛋白磷酸化。结论 我们的数据表明，RRMS 患者血清中存在的循环因子会引起 BBB 的生理和生化改变，即减少必需紧张性调节因子的表达，以及减少糖酵解的参与和线粒体电位的改变。由于这些最后的变化与免疫细胞的营养利用和代谢功能的改变有关；我们认为 MS 患者的 BBB 内皮可能同样经历代谢失调，导致通透性增强和疾病易感性增加。