iTRAQ-based quantitative proteomics analysis of immune thrombocytopenia patients before and after Qishunbaolier treatment.

Rationale: Treatment of immune thrombocytopenia (ITP) usually involves long-term use of immunosuppressive corticosteroids and splenectomy. However, these treatments often have side effects in patients. The Mongolian medicine Qishunbaolier (QSBLE) has a high curative effect, reduces the chances of relapse, and has no obvious side effects. This study was designed to identify potential therapeutic targets of QSBLE for treating ITP.

Methods: To reveal differences in protein expression between ITP patients (ITPs) before and after QSBLE treatment, comparative proteomics studies were performed using isobaric tags for relative and absolute quantification (iTRAQ). The analysis used nanospray liquid chromatography/tandem mass spectrometry (nano-LC/MS/MS) in positive ion electrospray ionization mode. Key proteins relevant to ITP were revealed by the Kyoto Encyclopedia of Genes and Genomes (KEGG) and other bioinformatics tools. Real-time polymerase chain reaction (RT-PCR) analysis was carried out for confirmation of differentially expressed proteins.

Results: A total of 982 differentially expressed proteins were identified in ITPs compared with the controls. Compared with the pre-QSBLE treatment group, 61 differentially expressed proteins were identified in the post-QSBLE treatment group, with 48 proteins being significantly upregulated and 13 downregulated. Twenty-nine pathways were significantly enriched. Q6N030 and other proteins were the key players in the protein-pathway network. Twenty proteins that may play important roles in the treatment of ITP were further filtered. RT-PCR and Western blot analyses further confirmed that MIF, PGK1 and IGHM were upregulated in ITPs after QSBLE treatment, in accordance with the proteomics data.

Conclusions: It is believed that the identified proteins and the results of bioinformatics analysis will provide a potential therapeutic target site for QSBLE for ITP therapy and biomarkers.