MicroRNAs (miRNAs) are critical post-transcriptional regulators, which play a crucial role in resistance to adverse environmental stress by regulating autophagy. However, the mechanism of miRNA involved in the autophagy regulation of shrimp under ammonia nitrogen stress is still limited. In the present study, ammonia nitrogen could induce hepatopancreas injury and oxidative stress of P. vannamei, and significantly increase the content of ROS in hemocytes by flow cytometry. Simultaneously, it is accompanied by autophagy occurred in the hemocytes and hepatopancreas. Furthermore, the qRT-PCR analysis revealed that the expression of pva-miR-252 in P. vannamei decreased significantly after ammonia nitrogen stress, and pva-miR-252 negatively regulated PvPI3K by binding to 3′UTR of PvPI3K by double-luciferase assay. Pva-miR-252 overexpression could significantly increase the level of autophagy, and restore the autophagy inhibition caused by Chloroquine in vitro , whereas silencing of pva-miR-252 resulted in the opposite effect. More importantly, overexpression of pva-miR-252 could enhance the activity of antioxidant enzymes and reduced the production of ROS of shrimp under ammonia nitrogen stress. In conclusion, pva-miR-252 could positively regulate autophagy through PvPI3K and improve the antioxidant enzyme activity of P. vannamei under ammonia nitrogen stress, and our study provides a novel theoretical molecular mechanism for further understanding the shrimp cope with a high ammonia nitrogen environment.

MicroRNAs (miRNAs) 是关键的转录后调节因子，通过调节自噬在抵抗不利环境压力方面发挥着至关重要的作用。然而，miRNA参与氨氮胁迫下虾自噬调控的机制尚有限。本研究中氨氮可诱导南美白对虾肝胰腺损伤和氧化应激，并通过流式细胞术显着增加血细胞中ROS的含量。同时伴随着血细胞和肝胰腺发生自噬。此外，qRT-PCR 分析表明，氨氮胁迫后南美白对虾pva-miR-252 的表达显着降低，pva-miR-252 对Pv负调控。PI3K 通过双荧光素酶测定与Pv PI3K 的3'UTR 结合。Pva-miR-252的过表达可以显着增加自噬水平，并恢复氯喹在体外引起的自噬抑制，而pva-miR-252的沉默导致相反的效果。更重要的是，pva-miR-252的过表达可以增强抗氧化酶的活性，减少氨氮胁迫下虾的ROS产生。综上所述，pva-miR-252可通过Pv PI3K正向调节自噬，提高南美白对虾的抗氧化酶活性 在氨氮胁迫下，我们的研究为进一步了解虾如何应对高氨氮环境提供了一种新的理论分子机制。