Screening on serum biomarkers in idiopathic pulmonary fibrosis patients by proteomics technology

Objective Applying the proteomics technology to identify proteins differentially in serums of idiopathic pulmonary fibrosis patients and normal population. Methods The study included serum samples from idiopathic pulmonary fibrosis group and normal controlled group with 30 cases of each, from the Second Hospital of Shandong University, between October 2014 and October 2015. Proteins differentially expressed in serums were quantified by the isobaric tags for relative and absolute quantization coupled with two-dimensional liquid chromatography/tandem mass spectrometry technology. The proteins were analyzed in terms of molecular function, cell location and biological processes for showing the key protein molecules which were related to the development of idiopathic pulmonary fibrosis. Results A total of 490 kinds of proteins (with confidence coefficient above 95%) were identified by mass spectrometry and 25 kinds of differentially expressed proteins were found. Compared with the control group, we found 4 types of up-regulated proteins and 21 down-regulated ones in the serum of idiopathic pulmonary fibrosis patients. Data from the Gene ontology analysis showed that most differentially expressed proteins were in the extracellular region (92%) while pathway enrichment analysis showed that most proteins were involved in the complement and coagulation cascade pathway. Conclusion Proteins related to the complement system coagulation cascade pathway, and the proteins function need to be further studied. Key words: Idiopathic pulmonary fibrosis; Proteomics; Serum biomarkers