Identification of Potential Biomarkers for Abdominal Pain in IBS Patients by Bioinformatics Approach

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Background: Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disease characterized by chronic abdominal discomfort and pain. The mechanisms of abdominal pain, as a relevant symptom, in IBS are still unclear. We aimed to explore the key genes and neurobiological changes specially involved in abdominal pain in IBS.Methods: Gene expression data (GSE36701) was downloaded from Gene Expression Omnibus (GEO) database. Fifty-three rectal mucosa samples from Irritable Bowel Syndrome with diarrhea (IBS-D) patients and 40 samples from healthy volunteers (HV) as controls were included. Differentially expressed genes (DEGs) between two groups were identified using the GEO2R online tool. Functional enrichment analysis of DEGs was performed on the DAVID database. Then a protein-protein interaction (PPI) network was constructed and visualized using STRING database and Cytoscape. Results: The microarray analysis demonstrated a subset of genes (CCKBR, CCL13ACPP, BDKRB2, GRPR, SLC1A2, NPFF, P2RX4, TRPA1, CCKBR, TLX2, MRGPRX3, PAX2, CXCR1) specially involved in pain transmission. Among these genes, we identified GRPR, NPFF and TRPA1 genes as potential biomarkers for irritating abdominal pain of IBS patients.Conclusions: Overexpression of certain pain-related genes (GRPR, NPFF and TRPA1) may contribute to chronic visceral hypersensitivity, therefore be partly responsible for recurrent abdominal pain or discomfort in IBS patients. Several synapses modification and biological process of psychological distress may be risk factors of IBS.