Institute of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
PLoS One. 2013 Sep 30;8(9):e74412. doi: 10.1371/journal.pone.0074412. eCollection 2013.
Surfactant proteins (SP) have been studied intensively in the respiratory system. Surfactant protein A and surfactant protein D are proteins belonging to the family of collectins each playing a major role in the innate immune system. The ability of surfactant protein A and surfactant protein D to bind various pathogens and facilitate their elimination has been described in a vast number of studies. Surfactant proteins are very important in modulating the host's inflammatory response and participate in the clearance of apoptotic cells. Surfactant protein B and surfactant protein C are proteins responsible for lowering the surface tension in the lungs. The aim of this study was an investigation of expression of surfactant proteins in the central nervous system to assess their specific distribution patterns. The second aim was to quantify surfactant proteins in cerebrospinal fluid of healthy subjects compared to patients suffering from different neuropathologies. The expression of mRNA for the surfactant proteins was analyzed with RT-PCR done with samples from different parts of the human brain. The production of the surfactant proteins in the brain was verified using immunohistochemistry and Western blot. The concentrations of the surfactant proteins in cerebrospinal fluid from healthy subjects and patients suffering from neuropathologic conditions were quantified using ELISA. Our results revealed that surfactant proteins are present in the central nervous system and that the concentrations of one or more surfactant proteins in healthy subjects differed significantly from those of patients affected by central autoimmune processes, CNS infections or cerebral infarction. Based on the localization of the surfactant proteins in the brain, their different levels in normal versus pathologic samples of cerebrospinal fluid and their well-known functions in the lungs, it appears that the surfactant proteins may play roles in host defense of the brain, facilitation of cerebrospinal fluid secretion and maintenance of the latter's rheological properties.
表面活性蛋白（SP）在呼吸系统中得到了深入研究。表面活性蛋白 A 和表面活性蛋白 D 是属于凝集素家族的蛋白，在先天免疫系统中都发挥着重要作用。大量研究描述了表面活性蛋白 A 和表面活性蛋白 D 结合各种病原体并促进其清除的能力。表面活性蛋白在调节宿主炎症反应和参与清除凋亡细胞方面非常重要。表面活性蛋白 B 和表面活性蛋白 C 是负责降低肺部表面张力的蛋白。本研究旨在调查表面活性蛋白在中枢神经系统中的表达，以评估其特定的分布模式。第二个目的是定量比较健康受试者和患有不同神经病理学疾病患者的脑脊液中的表面活性蛋白。使用 RT-PCR 分析来自人脑不同部位的样本中表面活性蛋白的 mRNA 表达。使用免疫组织化学和 Western blot 验证了脑内表面活性蛋白的产生。使用 ELISA 定量分析了健康受试者和患有神经病理学疾病患者脑脊液中表面活性蛋白的浓度。我们的结果表明表面活性蛋白存在于中枢神经系统中，健康受试者的一种或多种表面活性蛋白的浓度与受中枢自身免疫过程、中枢神经系统感染或脑梗死影响的患者的浓度有显著差异。基于表面活性蛋白在大脑中的定位、其在正常和病理脑脊液样本中的不同水平以及其在肺部中的众所周知的功能，似乎表面活性蛋白可能在宿主对大脑的防御、促进脑脊液分泌和维持后者的流变学特性方面发挥作用。
