Comprehensive Analysis of Serum microRNAs in Autoimmune Pancreatitis.

Autoimmune pancreatitis (AIP) is a rare disease that has recently emerged as a unique type of pancreatitis with a presumed autoimmune etiology. MicroRNA (miRNA) is a small non-coding RNA that targets multiple mRNAs. miRNAs might exist in serum in a stabilized form, suggesting its potential application as a biomarker. We here examined the miRNA expression profile in the serum of patients with AIP. miRNAs were prepared from serum samples of patients with various pancreatic diseases (AIP (n = 3, each before and after the steroid therapy), chronic pancreatitis (n = 5), pancreatic cancer (n = 5)) or healthy controls (n = 5). A human miRNA Oligo chip containing approximately 2,000 miRNAs was used to identify differentially expressed miRNAs. Ingenuity Pathway Analysis (IPA) was used for the integrated analysis of altered miRNAs. Microarray analysis identified miRNAs highly expressed in the serum of patients with AIP: 13 miRNAs vs. CP, 204 miRNAs vs. pancreatic cancer, and 19 miRNAs vs. healthy controls. miR-150-5p was commonly upregulated in AIP compared to the other samples. IPA revealed the most biological processes affected by the steroid therapy including cellular development, cellular growth, and cell movement. Our results identified that miRNAs were differentially expressed in the serum of AIP patients.