Abstract：
Exposure to excess ammonia-N (NH3/NH4+) in aquaculture can disrupt physiological function in shrimp leading to enhanced oxidative stress and apoptosis, but little is known concerning the post-transcriptional regulation mechanism. In this study, the first miR-200 family member in crustacean was identified and characterized from Litopenaeus vannamei (designed as Lva-miR-8-3p). Lva-miR-8-3p was highly expressed in eyestalks, brainganglion, and gills. The expression of Lva-miR-8-3p in gills significantly decreased after ammonia-N stress, and Lva-miR-8-3p was confirmed to target IKKβ 3\'UTR for negatively regulating IKKβ/NF-κB pathway. Overexpression of miR-8-3p promoted the hemolymph ammonia-N accumulation, total hemocyte count (THC) decrease, and gills tissue damage, thus resulting in a decreased survival rate of ammonia-exposed shrimp. Besides, Lva-miR-8-3p silencing could enhance the antioxidant enzymes activities and reduce the oxidative damage, whereas overexpression of Lva-miR-8-3p exerted the opposite effects. Furthermore, Lva-miR-8-3p overexpression was found to aggravate ammonia-N induced apoptosis in gills. In primarily cultured hemocytes, the cell viability decreased, the ROS content and caspase-3 activity increased after agomiR-8-3p transfection, while antagomiR-8-3p transfection caused the opposite change except the cell viability. These findings indicate that Lva-miR-8-3p acts as a post-transcriptional regulator in ammonia-N induced antioxidant response and apoptosis by negatively regulating IKKβ/NF-κB pathway.
摘要：
在水产养殖中暴露于过量的氨氮(NH3/NH4+)会破坏虾的生理功能，导致氧化应激和细胞凋亡增强。但对转录后调控机制知之甚少。在这项研究中,从凡纳滨对虾(设计为Lva-miR-8-3p)中鉴定并表征了甲壳类动物中的第一个miR-200家族成员.Lva-miR-8-3p在眼柄中高表达，脑神经节,还有ill.氨氮胁迫后,鸭中Lva-miR-8-3p的表达显著降低,证实Lva-miR-8-3p靶向IKKβ3'UTR负调控IKKβ/NF-κB通路。miR-8-3p过表达促进血淋巴氨氮积累,总血细胞计数（THC）减少，和ill组织损伤，从而导致暴露于氨的虾的存活率降低。此外,Lva-miR-8-3p沉默能增强抗氧化酶活性,减轻氧化损伤,而Lva-miR-8-3p的过表达发挥了相反的作用。此外，发现Lva-miR-8-3p过表达会加剧氨-N诱导的g细胞凋亡。在主要培养的血细胞中，细胞活力下降，agomiR-8-3p转染后，ROS含量和Caspase-3活性增加，而antagomiR-8-3p转染引起相反的变化，除了细胞活力。这些发现表明，Lva-miR-8-3p通过负调控IKKβ/NF-κB途径在氨氮诱导的抗氧化反应和细胞凋亡中起转录后调节因子的作用。
