Astakine is a crucial factor in the proliferation and differentiation of hematopoietic stem cells and is directly involved in hematopoiesis in crustaceans. To assess the role of Astakine in the innate immune system of Scylla paramamosain, the immune responses in healthy and Astakine-inhibited S. paramamosain were investigated in the present study. The RNA transcripts of Astakine were widely distributed in all examined tissues, with significantly higher levels of expression in hemocytes of both healthy and challenged S. paramamosain with Vibrio alginolyticus and WSSV. When Astakine was knocked down by RNA interference technology, immune-related genes, including Janus kinase, prophenoloxidase, hemocyanin, β-actin, myosin II essential light chain-like protein, signal transducer and activator of transcription, Relish, and C-type-lectin, were significantly down-regulated in hemocytes. The levels of phenoloxidaseactivity (PO), total hemocyte counts (THC) and hemocyte proliferation decreased significantly in hemocytes of Astakine-dsRNA treated S. paramamosain. After being challenged with V. alginolyticus and WSSV, the THC decreased significantly and the levels of hemocyte apoptosis increased significantly in Astakine-dsRNA treated S. paramamosain in comparison with those in infected groups without Astakine-dsRNA treatment. After being challenged with WSSV, the WSSV copies were significantly lower in Astakine-dsRNA treated groups than those in the WSSV infection group, which suggested that knockdown of Astakine was not conductive to WSSV replication and this might be associated with the decreasing THC. The results of survival analysis showed that the survival rate of V. alginolyticus or WSSV infected S. paramamosain decreased significantly following Astakine knockdown. These results suggested that RNA interference of Astakine might weaken the resistance of S. paramamosain to V. alginolyticus or WSSV infection. The weaken resistivity after knockdown Astakine might be related to the changes of important immune-related gene expression, THC, PO activity, proliferation and apoptosis of hemocytes.

中文翻译：

---

Astakine在Scylla paramamosain中对溶藻弧菌和白斑综合症病毒感染的作用。

Astakine是造血干细胞增殖和分化的关键因素，直接参与甲壳类动物的造血作用。为了评估Astakine在Sylla paramamosain的先天免疫系统中的作用，本研究对健康和Astakine抑制的S. paramamosain的免疫反应进行了研究。Astakine的RNA转录本广泛分布在所有检查过的组织中，健康的和挑战的副溶菌链球菌溶藻弧菌和WSSV的血细胞中的表达水平明显较高。当被RNA干扰技术击倒Astakine时，与免疫相关的基因，包括Janus激酶，原酚氧化酶，血蓝蛋白，β-肌动蛋白，肌球蛋白II必需的轻链样蛋白，信号转导和转录激活因子，Relish和C型凝集素 在血细胞中明显下调。Astakine-dsRNA处理的副嗜乳链球菌的血细胞中的酚氧化酶活性（PO），总血细胞计数（THC）和血细胞增殖水平显着降低。与未使用Astakine-dsRNA处理的感染组相比，经溶藻弧菌和WSSV攻击后，Astakine-dsRNA处理的S. paramamosain中的THC显着下降，血细胞凋亡水平显着增加。在受到WSSV攻击后，Astakine-dsRNA治疗组的WSSV拷贝数显着低于WSSV感染组的WSSV拷贝数，这表明Astakine的敲低与WSSV复制无关，这可能与THC降低有关。生存分析结果表明，V的生存率高。Astakine敲低后，溶有藻或WSSV的S. paramamosain感染明显减少。这些结果表明，Astakine的RNA干扰可能会削弱副嗜杀沙门氏菌对溶藻弧菌或WSSV感染的抵抗力。敲低Astakine后的抵抗力减弱可能与重要的免疫相关基因表达，THC，PO活性，血细胞增殖和凋亡的变化有关。