Targeted proteomics has advantages over earlier conventional technologies for protein detection. We developed and validated an LC/MRM-MS-based targeted proteomic method combined with immunoaffinity precipitation for the enrichment and detection of low abundance chemerin isoforms in human biofluids. After tryptic digestion, each chemerin isoform was characterized by isoform-specific peptides, and the absolute quantification was achieved by using stable isotope-labeled peptides as internal standards. In serum, follicular fluid and synovial fluid, a total of 6 chemerin isoforms were identified and quantified, among which a novel natural isoform 153Q was discovered for the first time. The relative content of the six chemerin isoforms in human serum was 157S ≫ 156F ≫ 158K > 154F ≥ 155A > 153Q in the ratio of 25:17:5:2.5:2.2:1, respectively. The absolute contents were in the range of 88-3.5 ng/mL. This distribution remained consistent among the 3 biofluids analyzed. Total chemerin were found to be increased in both polycystic ovary syndrome (serum and follicular fluid) and rheumatoid arthritis (serum) patients. However, chemerin isoform analysis revealed that only 156F & 157S were increased in the former, while 155A, 156F & 157S were increased in the latter. This demonstrates the potential of this method in detailed characterization of changes in chemerin isoforms that may be of clinical relevance.

中文翻译：

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使用基于 LC/MRM-MS 的靶向蛋白质组学方法和稳定同位素标记的标准品对人体生物体液中的 Chemerin 异构体进行分析

靶向蛋白质组学相对于早期的蛋白质检测常规技术具有优势。我们开发并验证了一种基于 LC/MRM-MS 的靶向蛋白质组学方法，结合免疫亲和沉淀，用于富集和检测人类生物体液中的低丰度凯莫瑞亚型。胰蛋白酶消化后，每个 chemerin 异构体都通过异构体特异性肽进行表征，并通过使用稳定同位素标记的肽作为内标来实现绝对定量。在血清、卵泡液和滑液中，共鉴定和定量了 6 种凯莫瑞亚型，其中首次发现了一种新型天然亚型 153Q。人血清中6种chemerin亚型的相对含量为157S≫156F≫158K>154F≥155A>153Q，比例分别为25:17:5:2.5:2.2:1。绝对含量在 88-3.5 ng/mL 的范围内。这种分布在分析的 3 种生物流体中保持一致。发现多囊卵巢综合征（血清和卵泡液）和类风湿性关节炎（血清）患者的总凯莫瑞增加。然而，chemerin亚型分析显示，前者仅增加了156F和157S，而后者增加了155A、156F和157S。这证明了该方法在详细表征可能具有临床相关性的凯莫瑞亚型变化方面的潜力。chemerin亚型分析显示，前者仅增加了156F和157S，而后者增加了155A、156F和157S。这证明了该方法在详细表征可能具有临床相关性的凯莫瑞亚型变化方面的潜力。chemerin亚型分析显示，前者仅增加了156F和157S，而后者增加了155A、156F和157S。这证明了该方法在详细表征可能具有临床相关性的凯莫瑞亚型变化方面的潜力。