Institute of Marine Research, SLCR-Sea Lice Research Centre, Nordnes, P. box 1870, 5817, Bergen, Norway.
Department of Biological Sciences, SLCR-Sea Lice Research Centre, University of Bergen, P. box 7803, 5020, Bergen, Norway.
Parasit Vectors. 2021 Apr 19;14(1):206. doi: 10.1186/s13071-021-04690-w.
The salmon louse (Lepeophtheirus salmonis) is a parasite of salmonid fish. Atlantic salmon (Salmo salar) exhibit only a limited and ineffective immune response when infested with this parasite. Prostaglandins (PGs) have many biological functions in both invertebrates and vertebrates, one of which is the regulation of immune responses. This has led to the suggestion that prostaglandin E (PGE) is important in the salmon louse host-parasite interaction, although studies of a salmon louse prostaglandin E synthase (PGES) 2 gene have not enabled conformation of this hypothesis. The aim of the present study was, therefore, to characterize two additional PGES-like genes.
Lepeophtheirus salmonis microsomal glutathione S-transferase 1 like (LsMGST1L) and LsPGES3L were investigated by sequencing, phylogenetics, transcript localization and expression studies. Moreover, the function of these putative PGES genes in addition to the previously identified LsPGES2 gene was analyzed in double stranded (ds) RNA-mediated knockdown (KD) salmon louse.
Analysis of the three putative LsPGES genes showed a rather constitutive transcript level throughout development from nauplius to the adult stages, and in a range of tissues, with the highest levels in the ovaries or gut. DsRNA-mediated KD of these transcripts did not produce any characteristic changes in phenotype, and KD animals displayed a normal reproductive output. The ability of the parasite to infect or modulate the immune response of the host fish was also not affected by KD.
Salmon louse prostaglandins may play endogenous roles in the management of reproduction and oxidative stress and may be a product of salmon louse blood digestions.
鲑鱼虱（Lepeophtheirus salmonis）是鲑鱼科鱼类的寄生虫。当这种寄生虫感染大西洋鲑鱼（Salmo salar）时，鱼只表现出有限且无效的免疫反应。前列腺素（PGs）在无脊椎动物和脊椎动物中具有许多生物学功能，其中之一是调节免疫反应。这导致人们提出前列腺素 E（PGE）在鲑鱼虱宿主-寄生虫相互作用中很重要，尽管对鲑鱼虱前列腺素 E 合酶（PGES）2 基因的研究未能证实这一假设。因此，本研究的目的是表征另外两个 PGES 样基因。
通过测序、系统发育、转录定位和表达研究，研究了鲑鱼虱微粒体谷胱甘肽 S-转移酶 1 样（LsMGST1L）和 LsPGES3L。此外，还分析了这些推定的 PGES 基因的功能，以及之前鉴定的 LsPGES2 基因在双链 RNA 介导的鲑鱼虱敲低（KD）中的功能。
对这三个推定的 LsPGES 基因的分析表明，从无节幼体到成虫阶段的整个发育过程中，以及在一系列组织中，转录水平都相当稳定，卵巢或肠道中的转录水平最高。这些转录本的 dsRNA 介导 KD 并未产生任何表型特征变化，KD 动物表现出正常的繁殖能力。寄生虫感染或调节宿主鱼免疫反应的能力也不受 KD 的影响。
鲑鱼虱前列腺素可能在生殖和氧化应激的管理中发挥内源性作用，并且可能是鲑鱼虱血液消化的产物。
