Dong Chaoling, Greathouse Kelsey M, Beacham Rebecca L, Palladino Steven P, Helton E Scott, Ubogu Eroboghene E
Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.
Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States.
Exp Neurol. 2017 Jun;292:35-45. doi: 10.1016/j.expneurol.2017.02.012. Epub 2017 Feb 16.
The molecular determinants of pathogenic leukocyte migration across the blood-nerve barrier (BNB) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are unknown. Specific disease modifying therapies for CIDP are also lacking. Fibronectin connecting segment-1 (FNCS1), an alternatively spliced fibronectin variant expressed by microvascular endothelial cells at sites of inflammation in vitro and in situ, is a counterligand for leukocyte α integrin (also known as CD49d) implicated in pathogenic leukocyte trafficking in multiple sclerosis and inflammatory bowel disease. We sought to determine the role of FNCS1 in CIDP patient leukocyte trafficking across the BNB in vitro and in severe chronic demyelinating neuritis in vivo using a representative spontaneous murine CIDP model. Peripheral blood mononuclear leukocytes from 7 untreated CIDP patients were independently infused into a cytokine-treated, flow-dependent in vitro BNB model system. Time-lapse digital video microscopy was performed to visualize and quantify leukocyte trafficking, comparing FNCS1 peptide blockade to relevant controls. Fifty 24-week old female B7-2 deficient non-obese diabetic mice with spontaneous autoimmune peripheral polyneuropathy (SAPP) were treated daily with 2mg/kg FNCS1 peptide for 5days via intraperitoneal injection with appropriate controls. Neurobehavioral measures of disease severity, motor nerve electrophysiology assessments and histopathological quantification of inflammation and morphometric assessment of demyelination were performed to determine in vivo efficacy. The biological relevance of FNCS1 and CD49d in CIDP was evaluated by immunohistochemical detection in affected patient sural nerve biopsies. 25μM FNCS1 peptide maximally inhibited CIDP leukocyte trafficking at the human BNB in vitro. FNCS1 peptide treatment resulted in significant improvements in disease severity, motor electrophysiological parameters of demyelination and histological measures of inflammatory demyelination. Microvessels demonstrating FNCS1 expression and CD49d+ leukocytes were seen within the endoneurium of patient nerve biopsies. Taken together, these results imply a role for FNCS1 in pathogenic leukocyte trafficking in CIDP, providing a potential target for therapeutic modulation.
慢性炎性脱髓鞘性多发性神经根神经病（CIDP）中致病性白细胞穿越血神经屏障（BNB）的分子决定因素尚不清楚。CIDP也缺乏特异性疾病修正疗法。纤连蛋白连接段1（FNCS1）是一种选择性剪接的纤连蛋白变体，在体外和原位炎症部位由微血管内皮细胞表达，是白细胞α整合素（也称为CD49d）的反配体，与多发性硬化症和炎症性肠病中的致病性白细胞运输有关。我们试图使用具有代表性的自发性小鼠CIDP模型，在体外和体内严重慢性脱髓鞘性神经炎中，确定FNCS1在CIDP患者白细胞穿越BNB中的作用。将7例未经治疗的CIDP患者的外周血单个核白细胞独立注入细胞因子处理的、流量依赖性的体外BNB模型系统。进行延时数字视频显微镜检查以可视化和量化白细胞运输，将FNCS1肽阻断与相关对照进行比较。50只24周龄的雌性B7-2缺陷型非肥胖糖尿病小鼠，患有自发性自身免疫性周围神经病（SAPP），通过腹腔注射2mg/kg FNCS1肽，每天治疗5天，并设置适当对照。进行疾病严重程度的神经行为测量、运动神经电生理评估以及炎症的组织病理学量化和脱髓鞘的形态学评估，以确定体内疗效。通过对受影响患者腓肠神经活检进行免疫组织化学检测，评估FNCS1和CD49d在CIDP中的生物学相关性。25μM FNCS1肽在体外最大程度地抑制了人BNB处的CIDP白细胞运输。FNCS1肽治疗导致疾病严重程度、脱髓鞘的运动电生理参数以及炎性脱髓鞘的组织学测量有显著改善。在患者神经活检的神经内膜内可见显示FNCS1表达的微血管和CD49d +白细胞。综上所述，这些结果表明FNCS1在CIDP致病性白细胞运输中起作用，为治疗调节提供了潜在靶点。
