Background: Peritoneal dialysis-associated peritonitis (PDAP) is the most common complication in peritoneal dialysis patients. We propose screening for characteristic expressed proteins in the dialysate of PDAP patients to provide clues for the diagnosis of PDAP and its therapeutic targets.
Methods: Dialysate samples were collected from patients with a first diagnosis of PDAP (n = 15) and from patients who had not experienced peritonitis (Control, n = 15). Data-independent acquisition (DIA) proteomic analysis was used to screen for differentially expressed proteins (DEPs). Co-expression networks were constructed via weighted gene co-expression network analysis (WGCNA) for detection of gene modules. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used for functional annotation of DEPs and gene modules. Hub proteins were validated using the parallel reaction monitoring (PRM) method.
Results: A total of 142 DEPs in the dialysate of PDAP patients were identified. 70 proteins were upregulated and 72 proteins were downregulated. GO and KEGG analysis showed that DEPs were mainly enriched in cell metabolism, glycolysis/glycogenesis and hypoxia-inducible factor-1 signaling pathway. Subsequently, a co-expression network was constructed and four gene modules were detected. Myeloperoxidase (MPO) and myeloperoxidase (HP) were the key proteins of the blue and turquoise modules, respectively. Additionally, PRM analysis showed that the expression of MPO and HP was significantly upregulated in the PDAP group compared to the non-peritonitis group, which was consistent with our proteomics data.
Conclusion: MPO and HP were differentially expressed in the dialysate of PDAP patients and may be potential diagnostic and therapeutic targets for PDAP.
Keywords: Differentially expressed proteins; Haptoglobin; Myeloperoxidase; Peritoneal dialysis-associated peritonitis; Proteomics.
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