Scavenger receptor C regulates antimicrobial peptide expression by activating toll signaling in silkworm, Bombyx mori
Scavenger receptor C regulates antimicrobial peptide expression by activating toll signaling in silkworm, Bombyx mori
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清道夫受体 C 通过激活家蚕中的 Toll 信号调节抗菌肽表达
DOI：
10.1016/j.ijbiomac.2021.09.084
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发表时间：
2021
影响因子：
8.2
通讯作者：
Hongjuan Cui
中科院分区：
文献类型：
--
作者：
Kui Zhang;Li Shen;Xue Wang;He Yang;Xiaolin Zhang;Guangzhao Pan;Chongyang Li;Haoyan Ji;Muhammad NadeemAbbas;Cong Li;Hongjuan Cui
清道夫受体（Scavenger receptor，PRR）是一种模式识别受体，在机体防御病原体的过程中发挥重要作用。清道夫受体C（SR-C）仅存在于无脊椎动物中，其功能尚未详细研究。本研究对家蚕SR-C同源基因进行了鉴定和分析。SR-C主要表达于血细胞和马氏管，在血细胞中持续表达。在蜕皮期和游走期血细胞中，mRNA和蛋白质水平均出现表达高峰。免疫荧光结果表明，它主要分布在血细胞的细胞膜上，包括类卵细胞和粒细胞。重组SR-C蛋白（rSR-C）可与不同类型的细菌和病原体相关分子模式（PAMPs）结合，与革兰氏阳性菌和赖氨酸型肽聚糖结合较强。SR-C的过表达诱导了Toll通路相关基因和抗菌肽的表达。SR-C基因的敲低降低了AMP的表达，抑制了Toll通路，但同时也削弱了家蚕幼虫的细菌清除能力，从而降低了家蚕幼虫的存活率。总之，SR-C是一种PRR，其通过增强血细胞中经由Toll途径的AMP表达来保护蚕免受细菌病原体的侵害。
Scavenger receptor is pattern-recognition receptor (PRR) that plays a crucial function in host defense against pathogens. Scavenger receptor C (SR-C) is present only in invertebrates and its function has not been studied in detail. In this study, an SR-C homologous gene from the silkworm, Bombyx mori, was identified and characterized. SR-C was largely expressed in hemocytes and Malpighian tubules, with continuous expression in hemocytes. The peak expression was observed in hemocytes during molting and wandering stages both at mRNA and protein levels. Furthermore, immunofluorescence demonstrated it to be mainly distributed in the cell membranes of hemocytes, including oenocytoids and granulocytes. The recombinant SR-C protein (rSR-C) could bind to different types of bacteria and pathogen-associated molecular patterns (PAMPs), with strong binding to gram-positive bacteria and Lys-type peptidoglycans. The overexpression of SR-C induced the expression of genes related to the Toll pathway and antibacterial peptides. While the knockdown of SR-C reduced the expression of AMPs and inhibited the Toll pathway, it impaired the bacterial clearance ability of silkworm larvae, thus decreasing silkworm larvae's survival rate. Altogether, SR-C is a PRR that protect silkworms against bacterial pathogens by enhancing the expression of AMPs expression via the Toll pathway in hemocytes.