Microarray profiling and functional analysis reveal the regulatory role of differentially expressed plasma circular RNAs in Hashimoto's thyroiditis.

Circular RNAs (circRNAs) have been revealed as being abundantly expressed in a variety of tissues and have been found to contribute to the regulation of many autoimmune diseases. Although previous studies demonstrated that the pathogenesis of Hashimoto's thyroiditis (HT) is related with epigenetic dysregulation, the exact mechanism remains unclear. The important role of thyroid-specific circRNAs in HT attracted much attention but without any report revealed their expression profile and function in plasma of HT. In this study, the circRNA expression profile in plasma of HT was explored for the first time by using Arraystar CircRNA Microarray technology. We obtained 22 differentially expressed circRNAs (fold change ≥ 2.0 or ≤  - 2.0, p < 0.05) in plasma of HT, including 7 upregulated circRNAs and 15 downregulated circRNAs. By constructing circRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network, we found that upregulated circRNAs may function as ceRNAs and affect the occurrence or development of HT through chemokine signaling pathway (p < 0.0001), HIF-1 signaling pathway (p = 0.02), and FoxO signaling pathway (p = 0.04). Notably, hsa_circ_0008193 verified by RT-qPCR were the major upregulation circRNAs involved in the chemokine signaling pathway. These results provide a comprehensive circRNA resource for further in-depth study of the regulatory mechanisms of circRNA in HT and may provide new insight into HT.