PLA2R1相关膜性肾病患者血浆差异表达多肽的鉴定

Identification of plasma differential peptids in PLA2R1-related membranous nephropathy patients

目的探讨M型磷脂酶A2受体(PLA2R1)相关膜性肾病患者血浆多肽谱的变化。方法选取28例确诊为原发性膜性肾病(PMN)且抗PLA2R1抗体阳性的患者(PMN组)和28名健康体检者(正常对照组)。采用纳升级高效液相色谱串联质谱(nano-HPLC-MS/MS)检测所有研究对象血浆多肽,筛选出PMN患者与正常对照者的差异表达多肽。对差异表达多肽进行生物信息学分析。采用液相色谱串联质谱(LC-MS/MS)对差异表达多肽进行验证。采用Spearman相关分析评估PMN患者血浆C4b与抗PLA2R1-IgG抗体的相关性。结果采用nano-HPLC-MS/MS检出903条多肽,有31条在PMN组和正常对照组之间呈差异表达,其中表达下调15条、表达上调16条;有8条来源于C4b。京都基因与基因组数据库(KEGG)通路分析结果显示,差异表达多肽的前体蛋白涉及的通路主要为补体和凝血级联。LC-MS/MS验证结果显示,PMN组血浆C4b水平显著低于正常对照组(P<0.001)。Spearman相关分析结果显示,PMN患者C4b与抗PLA2R1-IgG抗体无相关性(r=0.03,P=0.877)。结论C4b或可作为PLA2R1相关膜性肾病患者潜在的生物标志物。

Objective To investigate the changes of plasma peptide profiles of M-type phospholipase A2 receptor(PLA2R1)-related membranous nephropathy.Methods Totally,28 patients with primary membranous nephropathy(PMN)and positive anti-PLA2R1 antibody(PMN group)and 28 healthy subjects(healthy control group)were enrolled.The plasma peptides were determined by nano-high performance liquid chromatography tandem mass spectrometry(nano-HPLC-MS/MS),and the differentially expressed peptides between PMN and healthy control groups were screened.The differentially expressed peptides were analyzed bioinformatically,and liquid chromatography tandem mass spectrometry(LC-MS/MS)was used to verify them.Spearman correlation analysis was used to evaluate the correlation between plasma C4b and anti-PLA2R1-IgG antibodies in PMN patients.Results A total of 903 peptides were found,and 31 of them were expressed differentially between PMN and healthy control groups,with 15 being down-regulated and 16 being up-regulated.Totally,8 of them were from C4b.Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that the complement and coagulation cascade were primarily involved in the precursor proteins of differentially expressed peptides.According to the verification results,the plasma C4b level in PMN group was lower than that in healthy control group(P<0.001).The results of Spearman correlation analysis showed that plasma C4b in PMN patients had no correlation with anti-PLA2R1-IgG antibodies(r=0.03,P=0.877).Conclusions C4b could be a promising new biomarker in patients with PLA2R1-related membranous nephropathy.