Inflammatory bowel disease (IBD) is a kind of intestinal immune dysfunction disease, and its occurrence and prevalence are on the rise worldwide. As a chronic gastrointestinal disease, its pathogenesis is still unknown. Exosomes are vesicles in various body fluids that carry a variety of substances. They can mediate intercellular communication and long-distance transport of multiple media. In this study, we investigated the protein profile of serum exosomes from healthy people and IBD patients to explore a new serological biomarker for IBD. Initially, exosomes were extracted from serum samples, and the proteins within the exosomes were identified by label-free liquid chromatography/mass spectrometry (LC-MS/MS). Western blot and ELISA were used to assess the identified protein. To further analyze the target protein, an acute colitis mouse model was established, and exosomes in colonic tissue and serum were extracted to investigate the protein in them. Firstly, serum exosomes were extracted from samples, and proteins in exosomes were identified by LC-MS/MS. Through statistical analysis, we identified 633 proteins. Among these proteins, pregnancy zone protein (PZP) showed a marked difference between patients with IBD and healthy people, in that its expression level was much higher in the IBD patients This exosomal protein was associated with immunosuppressive effects. Also, the level of PZP in colon tissue exosomes and serum exosomes of acute colitis mice was significantly higher than that of the control group. Our findings indicated that serum exosome PZP was present at a high level in the IBD patients. Hence it might be a promising biomarker and enhance auxiliary diagnosis of IBD.

中文翻译：

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血清外泌体妊娠区蛋白作为炎症性肠病的有前途的生物标志物

炎症性肠病（IBD）是一种肠道免疫功能障碍性疾病，其发病率和患病率在世界范围内呈上升趋势。作为一种慢性胃肠道疾病，其发病机制尚不清楚。外泌体是各种体液中携带多种物质的囊泡。它们可以介导细胞间通讯和多种媒体的长距离传输。在这项研究中，我们调查了来自健康人和 IBD 患者的血清外泌体的蛋白质谱，以探索 IBD 的新血清学生物标志物。最初，从血清样品中提取外泌体，并通过无标记液相色谱/质谱（LC-MS/MS）鉴定外泌体中的蛋白质。Western印迹和ELISA用于评估鉴定的蛋白质。为了进一步分析目标蛋白，建立急性结肠炎小鼠模型，提取结肠组织和血清中的外泌体，研究其中的蛋白质。首先，从样品中提取血清外泌体，并通过 LC-MS/MS 鉴定外泌体中的蛋白质。通过统计分析，我们确定了 633 种蛋白质。在这些蛋白质中，妊娠区蛋白（PZP）在 IBD 患者和健康人之间表现出显着差异，因为它在 IBD 患者中的表达水平要高得多。这种外泌体蛋白与免疫抑制作用有关。此外，急性结肠炎小鼠结肠组织外泌体和血清外泌体中PZP的水平显着高于对照组。我们的研究结果表明，IBD 患者的血清外泌体 PZP 含量较高。