State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China.
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, School of Marine Sciences, Ningbo University, Ningbo, 315211, PR China.
Fish Shellfish Immunol. 2024 Jun;149:109592. doi: 10.1016/j.fsi.2024.109592. Epub 2024 Apr 27.
Akirin2 is pivotal for regulating host immunological responses in vertebrates, including antibacterial immunity and inflammation. However, the functional significance of Akirin2 in invertebrates remains largely unexplored. In this study, we cloned the complete cDNA sequence of Akirin2 from A. japonicus (AjAkirin2) and elucidated its immunological mechanism upon pathogen infection. The whole AjAkirin2 cDNA sequence spanned 1014 bp, which comprised a 630 bp open reading frame encoding 209 amino acids, a 230 bp 5'-untranslated region (UTR), and a 154 bp 3'-UTR. Spatial expression analysis displayed constitutive expression of AjAkirin2 in all examined tissues. Both mRNA and protein expression abundance of the AjAkirin2 showed considerably high in coelomocytes of sea cucumbers challenged with Vibrio splendidus or stimulated with lipopolysaccharide. In addition, we found that sea cucumbers with 10 CFU/mL V. splendidus infection had a lower survival rate upon AjAkirin2 knockdown. Mechanistically, the result of GST-pull down and co-IP assays indicated that AjAkirin2 directly interacted with Aj14-3-3ζ. Moreover, we also detected that AjAkirin2 positively regulated Aj14-3-3ζ expression in sea cucumber coelomocytes. Furthermore, the knockdown of AjAkirin2 or Aj14-3-3ζ resulted in increasing intracellular bacteria load and suppressed the expression of key genes of the NF-κB signaling pathway (p65 and p105) and inflammatory cytokines including IL-17, VEGF, and MMP-1. In summary, these results confirmed the critical role of AjAkirin2 in mediating innate immune responses against V. splendidus infection via interaction with Aj14-3-3ζ and thereby exerting antibacterial function.
Akirin2 对于调节脊椎动物的宿主免疫反应至关重要，包括抗菌免疫和炎症。然而，Akirin2 在无脊椎动物中的功能意义在很大程度上仍未得到探索。在这项研究中，我们从日本刺参（AjAkirin2）中克隆了完整的 Akirin2 cDNA 序列，并阐明了其在病原体感染时的免疫学机制。整个 AjAkirin2 cDNA 序列长 1014bp，包含一个 630bp 的开放阅读框，编码 209 个氨基酸，一个 230bp 的 5'-非翻译区（UTR）和一个 154bp 的 3'-UTR。空间表达分析显示 AjAkirin2 在所有检测到的组织中均有组成型表达。在受到灿烂弧菌或脂多糖刺激的海参腔肠细胞中，AjAkirin2 的 mRNA 和蛋白表达丰度均相当高。此外，我们发现 AjAkirin2 敲低的海参在受到 10 CFU/mL 灿烂弧菌感染时的存活率较低。在机制上，GST-pull down 和 co-IP 实验的结果表明 AjAkirin2 与 Aj14-3-3ζ 直接相互作用。此外，我们还检测到 AjAkirin2 可正向调节海参腔肠细胞中 Aj14-3-3ζ 的表达。此外，AjAkirin2 或 Aj14-3-3ζ 的敲低会导致细胞内细菌负荷增加，并抑制 NF-κB 信号通路的关键基因（p65 和 p105）和炎症细胞因子（包括 IL-17、VEGF 和 MMP-1）的表达。综上所述，这些结果证实了 AjAkirin2 通过与 Aj14-3-3ζ 相互作用在介导对灿烂弧菌感染的固有免疫反应中的关键作用，并发挥抗菌功能。
