Han Honglin, Wang Liqun, Xu Suifeng, Wang Shaowen, Yang Min, Han Chengzong, Qin Qiwei, Wei Shina
Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000, China.
Fish Shellfish Immunol. 2022 Mar;122:446-454. doi: 10.1016/j.fsi.2022.02.042. Epub 2022 Feb 23.
Macrophage receptor with collagenous structure (MARCO) is a scavenger receptor that plays a crucial role in the immune response against microbial infections. To clarify the roles of fish MARCO in Singapore grouper iridovirus (SGIV) infection, we identified and characterized Ec-MARCO in the orange-spotted grouper (Epinephelus coioides). The Ec-MARCO encoded a 370-amino acid protein with transmembrane region, coiled coil region and SR domain, which shared high identities with reported MARCO. The abundant transcriptional level of Ec-MARCO was found in spleen, head kidney and blood. And the Ec-MARCO expression was significantly up-regulated in grouper spleen (GS) cells after infection with SGIV in vitro. Subcellular localization analysis revealed that Ec-MARCO was mainly distributed in the cytoplasm and on the cell membrane. Ec-MARCO knockdown in vitro significantly inhibited SGIV infection in GS cells, as evidenced by reduced decreased SGIV major capsid protein (MCP) transcription and MCP protein expression. Further studies showed that Ec-MARCO knockdown positively regulated proinflammatory cytokines and interferon-stimulated genes, and enhanced IFN and ISRE promoter activities. However, overexpression of Ec-MARCO did not affect SGIV entry into host cells. In summary, our results suggested that Ec-MARCO affected SGIV infection by regulating antiviral innate immune response.
具有胶原结构的巨噬细胞受体（MARCO）是一种清道夫受体，在针对微生物感染的免疫反应中起关键作用。为阐明鱼类MARCO在新加坡石斑鱼虹彩病毒（SGIV）感染中的作用，我们在点带石斑鱼（Epinephelus coioides）中鉴定并表征了Ec-MARCO。Ec-MARCO编码一个含有跨膜区、卷曲螺旋区和SR结构域的370个氨基酸的蛋白质，与已报道的MARCO具有高度同源性。在脾脏、头肾和血液中发现Ec-MARCO具有丰富的转录水平。体外感染SGIV后，石斑鱼脾脏（GS）细胞中Ec-MARCO的表达显著上调。亚细胞定位分析显示，Ec-MARCO主要分布在细胞质和细胞膜上。体外敲低Ec-MARCO显著抑制了GS细胞中的SGIV感染，SGIV主要衣壳蛋白（MCP）转录减少和MCP蛋白表达降低证明了这一点。进一步研究表明，敲低Ec-MARCO可正向调节促炎细胞因子和干扰素刺激基因，并增强IFN和ISRE启动子活性。然而，Ec-MARCO的过表达并不影响SGIV进入宿主细胞。总之，我们的结果表明，Ec-MARCO通过调节抗病毒先天免疫反应影响SGIV感染。
