不稳定型心绞痛患者血浆蛋白标记物的蛋白质组学筛选

Screening of plasma biomarkers in patients with unstable angina pectoris with proteomics analysis

目的分析冠心病不稳定型心绞痛(UAP)与稳定型心绞痛(SAP)患者血浆中的差异蛋白质,筛选可能与UAP早期诊断密切相关的血浆蛋白标记物。方法分别收集2014年6月-2015年4月南方医科大学第三附属医院UAP及SAP血浆标本各60例,另收集体检科收集的血浆标本作为正常对照组(n=60)。随机取对照组(n=10)、UAP组(n=10)与SAP组(n=10)空腹血浆标本各100μl,分别等量混合成3组样本,去除血浆高丰度蛋白后,利用双向差异凝胶电泳(DIGE)技术进行蛋白分离,经差异软件分析后,采集UAP和SAP之间变化2倍以上的差异蛋白质点,利用基质辅助激光解吸电离-飞行时间/飞行时间质谱(MALDI-TOF/TOF MS)对差异蛋白点进行鉴定。每组随机选取40份血浆样本,选取UAP特异性差异蛋白进行ELISA验证。结果 UAP与SAP组患者血浆相比较,共筛选出10个表达量差异2倍以上的差异蛋白点,包括9个上调蛋白点,1个下调蛋白点。经质谱鉴定后,表达上调的蛋白包括纤维蛋白原γ链(FGG)、补体C4-B(C4B)、免疫球蛋白κ链C结构域(IGKC)和血红蛋白α亚基(HBA1);表达下调的蛋白是结合珠蛋白(HP)。与对照组比较后,在这些差异蛋白中共找到2个UAP特异性相关蛋白,即IGKC和HP。选取IGKC进行ELISA验证,结果表明,与对照组和SAP组相比较,UAP组样本中IGKC特异性表达上调(P<0.05),与DIGE验证结果一致。结论筛选到UAP特异性相关蛋白IGKC和HP,IGKC有可能成为UAP早期筛查及诊断的特异性生物标记物。

Objective To analyze and compare the differentially expressed plasma proteins between patients with stable angina pectoris （SAP） and unstable angina pectoris （UAP）, and search for the biomarkers that maybe used for early diagnosis of UAP. Methods Sixty plasma samples were collected respectively from normal controls group （N group）, SAP group and UAP group during Jun. 2014 to Apr. 2015 from the Third Affiliated Hospital of Southern Medical University. Ten samples （100μl） of each group were selected randomly to pool into 3 groups severally. After removing high-abundance proteins from plasma, two-dimensional difference gel electrophoresis （DIGE） was used to isolate the total proteins, and then the protein spots with more than 2-fold changes between UAP and SAP were picked up after the differential software analysis. Afterward, the varied proteins were identified by matrix assisted laser desorption ionization-time of flight/time of flight （MALDI-TOF/TOF） mass spectrometry （MS）. Finally, 40 plasma samples were collected respectively from N, SAP and UAP group, and the UAP specific differential proteins were selected to be verified by ELISA. Results A total of 10 varied protein spots with more than 2-fold changes in UAP and SAP were found including 9 up-regulated proteins and 1 down-regulated one. MS identification indicated that the up-regulated proteins included fibrinogen gamma chain （FGG）, complement C4-B （C4B）, immunoglobulin （Ig） kappa chain C region （IGKC） and hemoglobin subunit alpha （HBA1）, whereas the down-regulated one was haptoglobin （HP）. After comparing the varied proteins with that in N group, 2 specifically UAP-related proteins, IGKC and HP, were detected totally. IGKC was selected to validate by ELISA, and the corresponding results showed that IGKC was increased specifically in UAP plasma （P〈0.05） when compared with N and SAP group, which was consistent with DIGE. Conclusion IGKC and HP have been detected as specifically related proteins to UAP, and IGKC might serve as a potential specific biomarker for screening and early diagnosis of UAP.