The mechanisms of action of circRNAs in stem cells
(A) In ESCs, circRNAs (e.g., circBIRC6) regulate the generation of stemness-related genes (e.g., OCT4 and NANOG). (B) In ASCs, cia-cGAS binds to cGAS to impede cGAMP, resulting in suppression of type I interferons (IFNs) transcription. circRNAs (e.g., circPan3) affect the stability of mRNA. (C) In MSCs, circRNAs (e.g., circFOXP1) sequester miRNAs through Wnt, EGFR signaling pathways. Abbreviations: cGAMP, cyclic GMP-AMP; cGAS, cGAMP synthase; EGFR, epidermal growth factor receptor.