Study on serum proteomic characteristics of workers with rare earth samarium oxide pneumoconiosis

Abstract

Objective: To screen differential proteins in the serum of workers with rare earth samarium oxide pneumoconiosis, in order to provide new ideas for finding its early diagnostic biomarkers. Methods: In April 2019, three male workers diagnosed with samarium oxide pneumoconiosis at a rare earth factory in Baotou City, Inner Mongolia Autonomous Region were selected as the observation group, and three male workers who were not exposed to dust were selected as the control group. The serum was sequenced using the Label-free proteomic method to screen for differentially expressed proteins, followed by cluster of orthologous groups of proteins (COG) annotation, gene ontology (GO) enrichment analysis, and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis. The interaction gene library retrieval tool database and Cytoscape 3.9.1 software were used to draw protein-protein interaction networks. CytoHubba plugin was used to screen for differentially expressed proteins with high scores, and real-time fluorescence quantitative polymerase chain reaction (RT/q-PCR) was used to validate the proteomic sequencing results. Results: A total of 45 up-regulated differentially expressed proteins and 5 down-regulated differentially expressed proteins were screened out in the serum of workers with rare earth samarium oxide pneumoconiosis. In the COG functional classification, post-translational modifications, protein turnover, and chaperones were the most numerous. GO enrichment included 25 entries for biological processes such as complement activation (classical pathways), 15 entries for cellular components such as extracellular recombinants, and 10 entries for molecular functions such as protein binding. The pathways identified by KEGG enrichment analysis mainly included infectious diseases, immune system, signal transduction, and immune related diseases. The top 10 scoring proteins were haptoglobin, complement C1r subcomponent, complement C1s subcomponent, apolipoprotein C-Ⅲ, apolipoprotein A-Ⅱ, prothrombin, afamin, complement component C8 gamma chain, complement component C6, complement component C7. The RT/q-PCR validation results showed that the mRNA expression levels of haptoglobin, prothrombin and complement C1s subcomponent in the observation group were significantly higher than those in the control group, and the differences were statistically significant (P<0.05) . Conclusion: Ten differentially expressed proteins in the serum of workers with rare earth samarium oxide pneumoconiosis are screened, which provides a good idea for the screening of biomarkers for early diagnosis of samarium oxide pneumoconiosis.