Study Of Quantitative Proteomics In Screening Serum Biomarkers Of Rheumatoid Arthritis

Objective:Screen and verify differential proteins,further explore the pathogenesis of rheumatoid arthritis through bioinformatics analysis,and provide new ideas and theoretical basis for the research of rheumatoid arthritis diagnostic markers.Methods:A total of 21 patients with primary RA,21 patients with active RA and 21 healthy controls were recruited in this study.We used the Tandem Mass Tag(TMT)technique combined with liquid chromatography-tandem mass spectrometry to screen differentially expressed proteins between RA patients and controls.We also identified potential biomarkers involved in RA by analysing biological processes,cellular components,molecular functions,Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways and protein-protein interactions;We further verified the serum samples of rheumatoid arthritis patients and healthy controls by enzyme-linked immunosorbent assay(ELISA).Statistical analyses were carried out using SPSS v.20.0 and ROC(receiver operating characteristic)curve analyses were carried out using Medcalc software.Twosided p-values <0.05 were deemed to be statistically significant for all analyses.Results:1.Through TMT and LC-MS,we found 228 differential proteins in the primary RA group compared with the healthy control group,including 116 up-regulated proteins and 112 downregulated proteins,which were mainly extracellular-related and participated in immune effector response,response to wounding,vesicle-mediated transport and involved in protein binding;Compared with the healthy control group,there were 251 differential proteins in the active RA group,including 124 up-regulated proteins and 127 down-regulated proteins,which were mainly extracellular-related to participate in leukocyte mediated immunity,immune effector process,protein activation cascade and involve antigen binding.2.According to the bioinformatics analysis combined with the existing relevant literature,manual positioning of 12 proteins is closely related to RA: serum amyloid A1(SAA1),S100 calcium binding protein A8(S100A8),S100 calcium binding protein A9(S100A9),Leucine-rich alpha-2-glycoprotein(LRG1),coronin-1A(CORO1A),protein tyrosine phosphatase nonreceptor type 6(PTPN6),Ras-related protein Rap-1b(RAP1B),14-3-3η(YWHAH),α-actinin-1(ACTN1),interleukin-6 receptor subunit β(IL6ST),heat shock protein β1(HSPB1),Profilin-1(PFN1)3.We used ELISA technology to verify the differential proteins that were screened,and found that the expression levels of SAA1,RAP1 B,IL6ST,and LRG1 proteins in RA patients were significantly higher than those in healthy control group and were statistically significant.Conclusion:TMT technique plays an important role in the screening of RA related biomarkers and the pathogenesis of RA,SAA1,RAP1,IL6 ST and LRG1 proteins were considered to be differential proteins expressed in RA,which may be used as potential serum biomarkers to supplement the diagnosis of RA.