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。 养殖虾主要有两种，即黑虎虾（斑节对虾）和太平洋白色虾（南美白对虾）。 这两个物种都对病毒性疾病的爆发非常敏感，通常具有80- 100%的灾难性大规模死亡率。虾的抗病毒免疫反应尚未完全了解;然而，我们确实知道双链（ds）RNA，无论是否编码感染特异性的病毒序列，都可以提供针对病毒复制的保护。本研究将使用由我们的工业合作伙伴（Glysantis Inc;圭尔夫，ON）开发的新型植物糖原（PhG）纳米颗粒作为dsRNA的载体，用作虾饲料添加剂。 PhG在本申请中作为纳米颗粒是有吸引力的，因为它是无毒的、食品级的、可生物降解的、非免疫原性的，并且高度适合于化学修饰。 在初步研究中，我们已经证明，与单独的dsRNA相比，用dsRNA-PhG处理的水生动物细胞对先天性抗病毒基因的诱导更稳健（>10倍）。因此，使用dsRNA-PhG将减少保护虾所需的dsRNA的量，从而降低成本。除了这些发现的可销售性之外，这项研究还将拓宽我们对虾中dsRNA介导的抗病毒途径的理解，并为诊断工具的开发和虾免疫的基础研究产生连续的虾细胞系。结合这些知识将大大提高我们对虾先天抗病毒免疫的理解，改善这种经济上重要的动物，并积极影响加拿大公司，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.