Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China.
State Key Laboratory of Microbial Technology, Shandong University, Jinan, China.
Front Immunol. 2018 Aug 30;9:1928. doi: 10.3389/fimmu.2018.01928. eCollection 2018.
The Ras GTPase superfamily, including more than 100 members, plays a vital role in a number of cellular processes, such as cytoskeleton recombination, gene expression, and signaling pathway regulation. Some members of the superfamily participate in innate immunity in animals. However, there have been few studies of RhoA on this aspect. In the present study, we identified a RhoA GTPase in the shrimp and named it RhoA. Expression of was significantly upregulated in hemocytes and heart of shrimp challenged with . Overexpression of in shrimp caused the total bacterial number to decrease significantly and knockdown of increased the bacterial number obviously, with a consequent decline in shrimp survival. These results confirmed the antibacterial function of RhoA in shrimp. Further study showed that rate of phagocytosis of hemocytes was decreased in -knockdown shrimp. Interestingly, we observed that RhoA was translocated onto the hemocyte membrane at 1 h post . challenge. The expression levels of the β-integrin-mediated phagocytosis markers and declined significantly after knockdown of . These results suggested that the antibacterial function of RhoA was related to β-integrin-mediated phagocytosis in shrimp. Our previous study identified that a C-type lectin, hFcLec4, initiated β-integrin mediated phagocytosis after bacterial infection. Thus, knockdown of hFcLec4 and β-integrin was performed. The results showed that the translocation of RhoA from the cytoplasm to membrane was inhibited and the expression level of RhoA was decreased, suggesting that RhoA participated in hFcLec4-integrin mediated phagocytosis. Therefore, our study identified a new hFcLec4-integrin-RhoA dependent phagocytosis against bacterial infection in shrimp.
Ras GTPase 超家族包含超过 100 个成员，在许多细胞过程中发挥着重要作用，如细胞骨架重组、基因表达和信号通路调节。该超家族的一些成员参与动物的固有免疫。然而，关于 RhoA 在这方面的研究很少。在本研究中，我们在虾中鉴定了一种 RhoA GTPase，并将其命名为 RhoA。在受到刺激的虾的血细胞和心脏中，的表达显著上调。在虾中过表达 会导致总细菌数量显著减少，而敲低 会明显增加细菌数量，导致虾的存活率下降。这些结果证实了 RhoA 在虾中的抗菌功能。进一步的研究表明，血细胞的吞噬率在 -敲低的虾中降低。有趣的是，我们观察到 RhoA 在刺激后 1 小时转移到血细胞膜上。在敲低 后，β-整合素介导的吞噬作用标记物和的表达水平显著下降。这些结果表明，RhoA 的抗菌功能与虾中β-整合素介导的吞噬作用有关。我们之前的研究表明，一种 C 型凝集素 hFcLec4 在细菌感染后启动β-整合素介导的吞噬作用。因此，进行了 hFcLec4 和β-整合素的敲低。结果表明，RhoA 从细胞质向膜的易位被抑制，RhoA 的表达水平降低，表明 RhoA 参与了 hFcLec4-整合素介导的吞噬作用。因此，我们的研究鉴定了一种新的 hFcLec4-整合素-RhoA 依赖的吞噬作用，以抵抗虾中的细菌感染。
