Institute of Reproductive Health/Center of Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Guilin Medical University, Guilin 541000, China.
Acta Biochim Biophys Sin (Shanghai). 2022 Aug 25;54(8):1090-1099. doi: 10.3724/abbs.2022101.
Although circular RNAs (circRNAs) are found to play important roles in many pathophysiological processes, the canonical theory that they act as microRNA sponges is now more and more challenged, given that most circRNAs only have few binding sites in a particular microRNA. Our previous study revealed that some up-regulated circRNAs play protective roles in bisphenol A (BPA)-induced toxicity in GC-2 germ cells. Here by CCK-8 assay, apoptosis assay, qRT-PCR and western blot analysis, we further discover that circRNAs (represented by circDcbld2, circMapk1 and circTbcld20) can cooperatively sponge miR-214-3p and then up-regulate AKT1 in ameliorating BPA-induced reproductive toxicity. They share binding sites with miR-214-3p and collectively reinforce the sponging effects. In addition, the upstream regulation mechanism, proven by bioinformatics analysis and gain- and loss-of-function study, shows that down-regulation of RNA binding protein QKI5 after BPA exposure can increase the expressions of these protective circRNAs, and thus activate the cell protective process. The QKI5-circDcbld2/circMapk1/circTblcd20-miR-214-3p-AKT1 axis ameliorates the toxic effect of BPA on GC-2 cells. Many other circRNAs up-regulated upon BPA treatment and QKI5 down-regulation also show binding sites with miR-214-3p. Thus the above axis may also be extrapolated to other circRNAs. Our results enrich the context of circRNA sponge mode and may provide new ideas in future multiple nucleic acid therapy.
尽管环状 RNA（circRNAs）被发现在许多病理生理过程中发挥重要作用，但鉴于大多数 circRNAs 仅在特定 microRNA 中有几个结合位点，它们作为 microRNA 海绵的经典理论现在越来越受到挑战。我们之前的研究表明，一些上调的 circRNAs 在双酚 A（BPA）诱导的 GC-2 生殖细胞毒性中发挥保护作用。在这里，通过 CCK-8 测定、凋亡测定、qRT-PCR 和 Western blot 分析，我们进一步发现 circRNAs（以 circDcbld2、circMapk1 和 circTbcld20 为代表）可以协同海绵 miR-214-3p，然后上调 AKT1，从而改善 BPA 诱导的生殖毒性。它们与 miR-214-3p 共享结合位点，并共同增强海绵作用。此外，通过生物信息学分析和功能获得和缺失研究证明的上游调控机制表明，BPA 暴露后 RNA 结合蛋白 QKI5 的下调可以增加这些保护性 circRNAs 的表达，从而激活细胞保护过程。QKI5-circDcbld2/circMapk1/circTblcd20-miR-214-3p-AKT1 轴改善了 BPA 对 GC-2 细胞的毒性作用。BPA 处理和 QKI5 下调后上调的许多其他 circRNAs 也与 miR-214-3p 具有结合位点。因此，上述轴也可以推断到其他 circRNAs。我们的研究结果丰富了 circRNA 海绵模式的背景，并可能为未来的多种核酸治疗提供新的思路。
