The interaction of hsa_circ_0002594 and eIF4A3 promotes T-helper 2 cell differentiation by the regulation of PTEN

T helper (Th) 2 cell-medicated immune response participates in various immune diseases, especially in asthma. Circ_0002594 has been reported to be up-regulated in asthmatic patients, and was higher in Th2-high subgroups, but the specific mechanisms by which circ_0002594 regulating Th2 cells were still unclear. Here, we found that circ_0002594 was significantly up-regulated in CD4⁺ T cells of asthmatic patients. Circ_0002594 overexpression elevated Th2-related cytokine IL-4 production and reduced Th1-related cytokine INF-γ production, promoting Th2 cell differentiation, while circ_0002594 loss resulted in the opposite results. Additionally, eIF4A3 overexpression reversed the effects of circ_0002594 on the production of INF-γ, IL-4 and Th1/Th2 ratio by interacting with circ_0002594. Moreover, circ_0002594 interacted with eIF4A3 to reduce PTEN mRNA stability, thus down-regulating PTEN mRNA expression. Furthermore, eIF4A3 overexpression markedly reversed the significant down-regulation of PTEN protein level and the activation of PI3K/AKT/mTOR pathway in CD4⁺ T cells transfected with Lv-circ_0002594, suggesting the involvement of circ_0002594/eIF4A3/PTEN axis in the activation of PI3K/AKT/mTOR pathway. Also, rapamycin (the mTOR inhibitor) dramatically reversed the promotion effects of circ_0002594 overexpression on Th2 cells. In conclusion, our study demonstrated that circ_0002594 interacted with eIF4A3 to reduce PTEN mRNA stability, down-regulating PTEN expression, thereby activating the PI3K/AKT/mTOR pathway to promote Th2 cell differentiation. Our work may highlight novel insights into the molecular mechanism of circ_0002594 in regulating Th2 cell differentiation in asthma.