INS and type 1 diabetes mellitus: To investigate the potential involvement of circRNAs in β-cell destruction occurring during the initial stage of type 1 diabetes, the mouse insulin-secreting cell line MIN6 cells were treated with a mix of cytokines, 2.5 ng/mL IL-1β, 2.5 ng/mL TNF-α, and 25 ng/mL IFN-γ for 24 h.