Background: Exposure of pancreatic β-cell to proinflammatory cytokines released by islet-infiltrating immune cells will lead to impaired insulin production and secretion as well as β-cell apoptosis during the initial phase of type 1 diabetes (T1D). Circular RNAs (circRNAs) were newly discovered as a novel class of non-coding RNAs that are involved in many diseases. As little is known about their role in insulin-secreting cells, this study aimed to evaluate their contribution to inflammation-induced β-cell dysfunction.
Methods: CircRNA expression proﬁle in MIN6 cells stimulated with a mix of cytokines, including IL-1β, IFN-γ, and TNF-α, was detected by circRNA microarrays. The diﬀerentially expressed circRNAs were validated by qRT-PCR. The involvement of selected circRNAs was tested after their inhibition in MIN6 cells. MicroRNA target prediction software and multiple bioinformatic approaches were used to construct a map of circRNA-microRNA-mRNA interactions and predict possible functions and pathways of the circRNAs.
Results: 1020 upregulated and 902 downregulated circRNAs were detected in cytokines-treated β-cells with a set filter fold-change ≧1.5. By qRT-PCR, circRNA 006029 and 013053 were furtherly proved to be increased by 2.1 fold and 3.7 fold, while circRNA 000286 and 017277 were downregulated by 3.4 fold and 1.9 fold. Inhibition of circRNA 000286 and 017277 in β-cells, with or without stimulation of cytokines, could promote β-cell apoptosis and affect glucose-induced insulin secretion. GO analysis enriched terms such as anatomical structure development and intracellular, and the top pathways included Pathways in cancer and MAPK signaling pathway. It was also speculated that the two circRNAs may regulate the key genes involved in β-cell apoptosis and function, such as Bcl2 and Vamp2.
Conclusion: Our data showed circRNAs as novel regulators in proinflammatory cytokines-mediated β-cell dysfunction, and suggested the involvement of circRNAs in the development of T1D.
Z. Wang: None. Y. Zheng: None. Z. Zhou: None.
National Natural Science Foundation of China (81502359)