The liver plays a critical role in metabolic activity and is the body's first immune barrier, and maintaining liver health is particularly important for poultry production. MicroRNAs (miRNAs) are involved in a wide range of biological activities due to their capacity as posttranscriptional regulatory elements. A growing body of research indicates that miR-21-5p plays a vital role as a modulator of liver metabolism in various species. However, the effect of miR-21-5p on the chicken liver is unclear. In the current study, we discovered that the fatty liver had high levels of miR-21-5p. Then the qPCR, western blot, flow cytometry, ELISA, dual-luciferase, and immunofluorescence assays were respectively used to determine the impact of miR-21-5p in the chicken liver, and it turned out that miR-21-5p enhanced lipogenesis, oxidative stress, and inflammatory responses, which ultimately induced hepatocyte apoptosis. Mechanically, we verified that miR-21-5p can directly target NFIB and KLF3. Furthermore, our experiments revealed that the suppression of NFIB promoted apoptosis and inflammation, and the KLF3 inhibitor accelerated lipogenesis and enhanced oxidative stress. Furthermore, the co-transfection results suggest that the PI3K/AKT pathway is also involved in the process of miRNA-21-5p-mediate liver metabolism regulation. In summary, our study demonstrated that miRNA-21-5p plays a role in hepatocyte lipogenesis, oxidative stress, inflammation, and apoptosis, via targeting NFIB and KLF3 to suppress the PI3K/AKT signal pathway in chicken.

中文翻译：

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miRNA-21-5p通过靶向NFIB和KLF3抑制PI3K/AKT信号通路诱导鸡肝脂肪生成

肝脏在代谢活动中起着至关重要的作用，是人体的第一道免疫屏障，保持肝脏健康对于家禽生产尤为重要。 MicroRNA (miRNA) 由于其作为转录后调控元件的能力而参与广泛的生物活动。越来越多的研究表明，miR-21-5p 在不同物种的肝脏代谢调节剂中发挥着至关重要的作用。然而，miR-21-5p对鸡肝的影响尚不清楚。在当前的研究中，我们发现脂肪肝中存在高水平的miR-21-5p。然后分别采用qPCR、western blot、流式细胞术、ELISA、双荧光素酶和免疫荧光测定法测定miR-21-5p对鸡肝脏的影响，结果发现miR-21-5p增强了脂肪生成，氧化应激和炎症反应，最终诱导肝细胞凋亡。从机械角度，我们验证了 miR-21-5p 可以直接靶向 NFIB 和 KLF3。此外，我们的实验表明，抑制 NFIB 会促进细胞凋亡和炎症，而 KLF3 抑制剂会加速脂肪生成并增强氧化应激。此外，共转染结果表明PI3K/AKT通路也参与了miRNA-21-5p介导的肝脏代谢调节过程。总之，我们的研究表明，miRNA-21-5p 通过靶向 NFIB 和 KLF3 抑制鸡的 PI3K/AKT 信号通路，在肝细胞脂肪生成、氧化应激、炎症和细胞凋亡中发挥作用。