Circular RNA hsa_circ_0003738 inhibits the suppressive function of Tregs in psoriatic patients by targeting miR-562/IL-17A and miR-490-5p/IFN-γ signaling pathway

Abstract Dysfunction in the suppressive function of Tregs has been related to the pathogenesis of psoriasis. Accumulating evidence has demonstrated the importance of circular RNAs (circRNAs) in regulating various biological process, such as cell proliferation, apoptosis, etc. However, the role of circRNAs in modulating the suppressive functions of psoriatic Tregs and the underlying mechanisms have not been investigated. Here by using circRNA microarray analysis, we discovered 4 upregulated and 4 downregulated circRNAs in psoriatic Tregs. qRT-PCR further confirmed a significant increase of circ_0003738 in psoriatic Tregs. Importantly, knockdown of circ_0003738 by lentivirus in psoriatic Tregs could restore their suppressive functions via inhibiting the secretion of proinflammatory cytokines IL-17A and IFN-γ. Moreover, we found that circ_0003738 could bind to miR-562 to release the inhibition of target gene IL-17RA, thus promoting IL-17A signaling in psoriatic Tregs. Parallelly, circ_0003738 acted also as sponge for miR-490-5p and relieve inhibition for the target gene IFNGR2, which promoted IFN-γ signaling in psoriatic Tregs. Our study demonstrated that upregulated circ_0003738 decreased the suppressive function of psoriatic Tregs via miR-562/IL17RA and miR-490-5p/IFNGR2 axis, which indicated the involvement of circRNAs in the pathogenesis of dysfunctional Tregs. These findings will provide new therapeutic targets for the treatment of psoriasis.