Discovery of SERPINA3 as a candidate urinary biomarker of lupus nephritis activity
Discovery of SERPINA3 as a candidate urinary biomarker of lupus nephritis activity
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DOI：
10.1093/rheumatology/key301
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发表时间：
2019-02-01
期刊：
影响因子：
5.5
通讯作者：
Aronow, Bruce
中科院分区：
文献类型：
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作者：
Turnier, Jessica L.;Brunner, Hermine I.;Aronow, Bruce
目标。我们使用一种无偏见的蛋白质组学方法来确定预测LN慢性化的候选尿液生物标记物(CUBM)，并在更大的队列中进行验证。在这项横断面的初步研究中，我们选择了20名LN受损程度不同的儿童(发现队列)的肾脏活检收集的尿液，并使用等压标记进行了蛋白质组分析，以进行相对和绝对定量(ITRAQ)。我们根据LN的慢性化程度识别差异排泄的蛋白质，并试图通过生物网络分析，使用具有关联和不同功能的分层聚类的Log10归一化相对丰度数据来区分显示不同相对表达模式的标记。对于每个CUBM，我们对验证队列(n=41)的尿液进行了特定的ELISA，并进行了方差分析，以检测LN慢性化和LN活动性调整之间的差异。我们用免疫组织化学方法检测LN活检组织中CUBM的表达。ITRAQ从发现的队列中检测到112种尿蛋白，其中51种在所有重复中都可以定量。简单的方差分析揭示了四个差异表达的、与慢性性相关的蛋白质(P值和lt；0.05)。进一步的相关性和网络分析导致为LN慢性性选择了7个CUBM。在验证队列中，没有一种CUBM区分LN的慢性程度；然而，尿SERPINA3与LN的组织学活动呈中度正相关。免疫组织化学进一步证实SERPINA3表达于近端肾小管上皮细胞和内皮细胞。我们确定SERPINA3，一种已知的中性粒细胞组织蛋白酶G和血管紧张素II产生的抑制剂，作为一种潜在的尿液生物标记物来帮助量化LN的活动。
Objectives. We used an unbiased proteomics approach to identify candidate urine biomarkers (CUBMs) predictive of LN chronicity and pursued their validation in a larger cohort.Methods. In this cross-sectional pilot study, we selected urine collected at kidney biopsy from 20 children with varying levels of LN damage (discovery cohort) and performed proteomic analysis using isobaric tags for relative and absolute quantification (iTRAQ). We identified differentially excreted proteins based on degree of LN chronicity and sought to distinguish markers exhibiting different relative expression patterns using hierarchically clustered log10-normalized relative abundance data with linked and distinct functions by biological network analyses. For each CUBM, we performed specific ELISAs on urine from a validation cohort (n = 41) and analysis of variance to detect differences between LN chronicity, with LN activity adjustment. We evaluated for CUBM expression in LN biopsies with immunohistochemistry.Results. iTRAQ detected 112 proteins in urine from the discovery cohort, 51 quantifiable in all replicates. Simple analysis of variance revealed four differentially expressed, chronicity-correlated proteins (P-values < 0.05). Further correlation and network analyses led to selection of seven CUBMs for LN chronicity. In the validation cohort, none of the CUBMs distinguished LN chronicity degree; however, urine SERPINA3 demonstrated a moderate positive correlation with LN histological activity. Immunohistochemistry further demonstrated SERPINA3 staining in proximal tubular epithelial and endothelial cells.Conclusion. We identified SERPINA3, a known inhibitor of neutrophil cathepsin G and angiotensin II production, as a potential urine biomarker to help quantify LN activity.