Screening and functional analysis of differential proteins in peripheral plasma of spinal tuberculosis patients based on proteomics

English Keywords:Spinal tuberculosis  Proteomics  Differential protein  Signaling pathway

English Abstract:

  【Abstract】 Objectives: To screen the differentially expressed proteins in peripheral plasma of patients with spinal tuberculosis with proteomics technology to provide reference for the study of the pathogenic mechanism and metabolic pathway of spinal tuberculosis. Methods: Peripheral blood was collected from 30 patients with spinal tuberculosis and 30 healthy volunteers, and the peripheral plasma from three patients with spinal tuberculosis(observation group) and three healthy volunteers(control group) was identified by isobaric tags for relative and absolute quantification(iTRAQ) based proteomics technique and liquid chromatography-mass spectrometry analysis for differential proteins to screen the proteins with significant expression differences(FC>1.2, P<0.05), and enrichment analysis was performed through Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG). Then, plasma from spinal tuberculosis patients and healthy volunteers was tested by real-time fluorescent quantitative reverse transcription polymerase chain reaction(RT-PCR) and enzyme-linked immunosorbent assay(ELISA) to verify the differential genes and proteins. Results: A total of 16 proteins were screened in the peripheral plasma of patients with spinal tuberculosis that were significantly different from those of the control group. Among them, 11 were up-regulated[lipopolysaccharide-binding protein(LBP), S100-A8, S100-A9, serum amyloid A-2 protein(SAA2), leucine-rich alpha-2 glycoprotein(LRG2), proteoglycan 4 (PRG4), complement factor I(CFI), alpha-1-antitrypsin(SERPINA1), cathepsin D(CTSD), ceruloplasmin(CP), and lambda-immunoglobulin variable 4-60(IGLV4-60)] and 5 proteins were down-regulated[vinculin(VCL), immunoglobulin heavy variable 3-64D(IGHV3-64D), immunoglobulin kappa variable 2D-29(IGKV2D-29), non-functional immunoglobulin kappa variable 6D-41(IGKV6D-41), and immunoglobulin heavy variable 1-45(IGHV1-45)]. The gene and protein expressions of LBP, S100-A8, and S100-A9 proteins were significantly elevated in the peripheral plasma of patients with spinal tuberculosis compared with those of control group(P<0.05). They mainly involved in the interleukin-17 signaling pathway and autophagy signaling pathway, where they were associated with inflammation, autophagy, chemokines and other biological functions. The gene and protein expressions of SAA2, LRG2, PRG4, CF1, SERPINA1, CTSD, CP, and VCL were not statistically different from those of the control group; the gene expression of IGLV4-60, IGHV3-64D, IGKV2D-29, IGKV6D-41, and IGHV1-45 were not significantly different from those of the control group(P>0.05), and the protein expression was not validated. Conclusions: Proteomics can be used to screen differential proteins in peripheral blood of patients with spinal tuberculosis and study the pathogenesis of spinal tuberculosis. LBP, S100-A8 and S100-A9 proteins may be important expression proteins related to the pathogenesis of spinal tuberculosis, which proteins mainly participate in IL-17 signaling pathway and autophagy-related signal pathway, and focus on biological functions such as inflammation, autophagy and chemokines.