Combined signatures of serum proteome and transcriptome in patients with recurrent aphthous ulcer

Objectives Recurrent aphthous ulcer (RAU) is a common oral disease with unclear mechanism. This study aimed to explore the serum signatures of RAU patients via proteomic and transcriptomic analysis. Methods This study was based on clinical observation. Part of serum was used for clinical tests, while the rest was processed for isobaric tags for relative and absolute quantitation (ITRAQ) labeling coupled with two‐dimensional liquid chromatography–tandem mass spectrometry (2D LC‐MS/MS) combined with microRNA (miRNA) microarrays. Bioinformatic analysis was then used to obtain significant signatures, which was verified by ELISA, qRT‐PCR, and dual‐luciferase reporter gene assays. Results Clinical data showed that triglyceride level, white blood cell count, and neutrophils percentage were increased in RAU group, while lymphocytes percentage was decreased. ITRAQ‐2D LC‐MS/MS identified 22 upregulated and 33 downregulated proteins in RAU group. Simultaneously, miRNA microarrays identified 64 upregulated and 31 downregulated miRNAs. After integrative bioinformatic analysis and verification, three miRNA‐protein pairs, mainly involved in oxidative stress and inflammation responses, were obtained. Additionally, the interaction network indicated the crucial role of complement and coagulation cascade pathway in RAU. Conclusions Our study revealed that complement and coagulation cascade pathway, oxidative stress, and inflammation responses may act as vital factors in pathogenesis of RAU.