Chiasserini Davide, van Weering Jan R T, Piersma Sander R, Pham Thang V, Malekzadeh Arjan, Teunissen Charlotte E, de Wit Heidi, Jiménez Connie R
OncoProteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands.
Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, VU University Medical Center, The Netherlands.
J Proteomics. 2014 Jun 25;106:191-204. doi: 10.1016/j.jprot.2014.04.028. Epub 2014 Apr 24.
Extracellular vesicles (EVs) are present in human cerebrospinal fluid (CSF), yet little is known about their protein composition. The aim of this study is to provide a comprehensive analysis of the proteome of CSF EVs by electron microscopy and high resolution tandem mass spectrometry (MS/MS) in conjunction with bioinformatics. We report an extensive catalog of 1315 proteins identified in EVs isolated from two different CSF pools by ultracentrifugation, including 230 novel EV proteins. Out of 1315 proteins, 760 were identified in both CSF pools and about 30% of those were also quantitatively enriched in the EV fraction versus the soluble CSF fraction. The proteome of CSF EVs was enriched in exosomal markers such as alix and syntenin-1, heat shock proteins and tetraspanins and contained a high proportion of brain-derived proteins (n=373). Interestingly, several known biomarkers for neurodegenerative diseases such as the amyloid precursor protein, the prion protein and DJ-1 were identified in the EV fractions. Our dataset represents the first comprehensive inventory of the EV proteome in CSF, underscoring the biomarker potential of this organelle. Further comparative studies on CSF EVs isolated from patients diagnosed with neurological disorders are warranted. Data are available via ProteomeXchange with identifier PXD000608. Biological significance In this study we analyzed the protein composition of extracellular vesicles isolated from pooled samples of human cerebrospinal fluid (CSF). CSF is a colorless fluid surrounding the brain and the spinal cord, important for the physiology of the central nervous system, ensuing mechanical protection, regulation of brain blood flow and elimination of byproducts of the brain. Since brain (patho)physiology is reflected in CSF, this biological fluid represents an ideal source of soluble and vesicle-based biomarkers for neurological diseases. Here we confirm the presence of exosome-like extracellular vesicles in CSF, underscoring a potential role in the physiology of the brain. These extracellular vesicles provide a rich source of candidate biomarkers, representing a brain "fluid biopsy". Most interestingly, the involvement of extracellular vesicles in transferring toxic proteins such as α-synuclein and β-amyloid has been postulated as one of the mechanisms involved in the spreading of neurodegeneration to different brain areas. In line with this, we show that human CSF extracellular vesicles contain prionogenic proteins such as the amyloid precursor protein and the prion protein. Delineating the protein composition of extracellular vesicles in CSF is a first and crucial step to comprehend their origin and their function in the central nervous system and to establish their biomarker potential.
细胞外囊泡（EVs）存在于人类脑脊液（CSF）中，但其蛋白质组成却鲜为人知。本研究旨在通过电子显微镜、高分辨率串联质谱（MS/MS）结合生物信息学对脑脊液EVs的蛋白质组进行全面分析。我们报告了通过超速离心从两个不同脑脊液样本中分离出的EVs中鉴定出的1315种蛋白质的详细目录，其中包括230种新型EV蛋白。在这1315种蛋白质中，有760种在两个脑脊液样本中均被鉴定出来，其中约30%在EV组分中相对于可溶性脑脊液组分也有定量富集。脑脊液EVs的蛋白质组富含外泌体标志物，如Alix和syntenin-1、热休克蛋白和四跨膜蛋白，并且含有高比例的脑源性蛋白质（n = 373）。有趣的是，在EV组分中鉴定出了几种神经退行性疾病的已知生物标志物，如淀粉样前体蛋白、朊病毒蛋白和DJ-1。我们的数据集代表了脑脊液中EV蛋白质组的首个全面清单，突显了这种细胞器的生物标志物潜力。有必要对从诊断为神经系统疾病的患者中分离出的脑脊液EVs进行进一步的比较研究。数据可通过ProteomeXchange获得，标识符为PXD000608。生物学意义 在本研究中，我们分析了从人类脑脊液（CSF）混合样本中分离出的细胞外囊泡的蛋白质组成。脑脊液是包围大脑和脊髓的无色液体，对中枢神经系统的生理功能很重要，可提供机械保护、调节脑血流量并清除大脑的副产品。由于大脑（病理）生理学反映在脑脊液中，这种生物液体代表了神经系统疾病可溶性和基于囊泡的生物标志物的理想来源。在这里，我们证实了脑脊液中存在类似外泌体的细胞外囊泡，突显了其在大脑生理学中的潜在作用。这些细胞外囊泡提供了丰富的候选生物标志物来源，代表了一种脑部“液体活检”。最有趣的是，细胞外囊泡参与转运有毒蛋白质（如α-突触核蛋白和β-淀粉样蛋白）被假定为神经退行性变扩散到不同脑区的机制之一。与此一致，我们表明人类脑脊液细胞外囊泡含有朊病毒生成蛋白，如淀粉样前体蛋白和朊病毒蛋白。描绘脑脊液中细胞外囊泡的蛋白质组成是理解其起源及其在中枢神经系统中的功能并确定其生物标志物潜力的首要关键步骤。
