Using phytoglycogen to deliver long dsRNA molecules as an antiviral drug in shrimp

虾是世界上价值最大的单一海鲜商品，2017年估计为400亿美元。养殖对虾产量主要由两种虾种组成，即黑虎对虾（Penaeus monodon）和太平洋白对虾（Penaeus vanamei）。这两个物种都非常容易受到病毒性疾病爆发的影响，通常会造成80-100%的灾难性大规模死亡率。对虾的抗病毒免疫反应尚不完全清楚；然而，我们确实知道，无论是否编码特定于感染的病毒序列，双链RNA （ds）都可以提供防止病毒复制的保护。本研究将使用由我们的工业合作伙伴（Glysantis Inc; Guelph， ON）开发的一种新型植物糖原（PhG）纳米颗粒作为dsRNA的载体，用于虾饲料添加剂。PhG作为纳米颗粒在该应用中具有吸引力，因为它无毒，食品级，可生物降解，非免疫原性，并且高度适合化学修饰。在初步研究中，我们已经证明，与单独使用dsRNA相比，用dsRNA- phg处理的水生动物细胞对先天抗病毒基因的诱导更强（bb10倍）。因此，使用dsRNA- phg可以减少保护虾所需的dsRNA数量，从而降低成本。除了这些发现的市场价值外，本研究还将拓宽我们对虾中dsrna介导的抗病毒途径的理解，并为虾免疫诊断工具的开发和基础研究提供连续的虾细胞系。结合这些知识将大大提高我们对虾的先天抗病毒免疫的理解，改善这种经济上重要的动物，并对加拿大公司产生积极影响，产生新的收入来源和就业机会。

Shrimp is the largest single seafood commodity by value in the world, estimated at $40 billion in 2017. Aquaculture shrimp production is dominated by two species, the black tiger shrimp (Penaeus monodon) and the pacific white shrimp (Penaeus vannamei). Both of these species are exquisitely susceptible to outbreaks of viral disease, generally with catastrophic mass mortalities ranging from 80-100%. The antiviral immune response in shrimp is not fully understood; however, we do know that double-stranded (ds)RNA, whether coding for virus sequences specific to the infection or not can lend protection against virus replication. The present study will use a novel phytoglycogen (PhG) nanoparticle, developed by our industrial partner (Glysantis Inc; Guelph, ON) as a carrier for dsRNA to be used as a shrimp feed additive. PhG is attractive as a nanoparticle in this application because it is non-toxic, food-grade, biodegradable, non-immunogenic, and highly amenable to chemical modifications. In preliminary studies we have demonstrated that aquatic animal cells treated with dsRNA-PhG mounted a more robust (>10 fold) induction of innate antiviral genes when compared to dsRNA alone. Thus using dsRNA-PhG would reduce the amount of dsRNA needed to protect shrimp, thus reducing cost. In addition to the marketability of these findings, this research will also broaden our understanding of dsRNA-mediated antiviral pathways in shrimp and generate a continuous shrimp cell line for the development of diagnostic tools, and basic research on shrimp immunity. Combined this knowledge will significantly progress our understanding of shrimp innate antiviral immunity, for the betterment of this economically important animal, as well as positively impact a Canadian company, producing novel revenue streams and employment opportunities.