Department of Medicine, Division of Gastroenterology and Hepatology, Stanford School of Medicine, Stanford, California, USA.
Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA.
J Virol. 2022 Aug 10;96(15):e0055022. doi: 10.1128/jvi.00550-22. Epub 2022 Jul 12.
The basis for rotavirus (RV) host range restriction (HRR) is not fully understood but is likely multigenic. RV genes encoding VP3, VP4, NSP1, NSP2, NSP3, and NSP4 have been associated with HRR in various studies. With the exception of NSP1, little is known about the relative contribution of the other RV genes to HRR. VP4 has been linked to HRR because it functions as the RV cell attachment protein, but its actual role in HRR has not been fully assessed. We generated a collection of recombinant RVs (rRVs) in an isogenic murine-like RV genetic background, harboring either heterologous or homologous VP4 genes from simian, bovine, porcine, human, and murine RV strains, and characterized these rRVs and . We found that a murine-like rRV encoding a simian VP4 was shed, spread to uninoculated littermates, and induced diarrhea comparably to rRV harboring a murine VP4. However, rRVs carrying VP4s from both bovine and porcine RVs had reduced diarrhea, but no change in fecal shedding was observed. Both diarrhea and shedding were reduced when VP4 originated from a human RV strain. rRVs harboring VP4s from human or bovine RVs did not transmit to uninoculated littermates. We also generated two rRVs harboring reciprocal chimeric murine or bovine VP4. Both chimeras replicated and caused disease as efficiently as the parental strain with a fully murine VP4. These data suggest that the genetic origin of VP4 partially modulates HRR in the suckling mouse and that both the VP8* and VP5* domains independently contribute to pathogenesis and transmission. Human group A rotaviruses (RVs) remain the most important cause of severe acute gastroenteritis among infants and young children worldwide despite the introduction of several safe and effective live attenuated vaccines. The lack of knowledge regarding fundamental aspects of RV biology, such as the genetic basis of host range restriction (HRR), has made it difficult to predictively and efficiently design improved, next-generation live attenuated rotavirus vaccines. Here, we engineered a collection of VP4 monoreassortant RVs to systematically explore the role of VP4 in replication, pathogenicity, and spread, as measures of HRR, in a suckling mouse model. The genetic and mechanistic bases of HRR have substantial clinical relevance given that this restriction forms the basis of attenuation for several replication-competent human RV vaccines. In addition, a better understanding of RV pathogenesis and the determinants of RV spread is likely to enhance our ability to improve antiviral drug and therapy development.
轮状病毒（RV）宿主范围限制（HRR）的基础尚不完全清楚，但可能是多基因的。在各种研究中，编码 VP3、VP4、NSP1、NSP2、NSP3 和 NSP4 的 RV 基因与 HRR 相关。除了 NSP1 之外，关于其他 RV 基因对 HRR 的相对贡献知之甚少。VP4 与 HRR 相关，因为它是 RV 细胞附着蛋白，但它在 HRR 中的实际作用尚未完全评估。我们在类似于鼠的 RV 遗传背景中生成了一组重组 RV（rRV），其中包含来自灵长类动物、牛、猪、人、和鼠 RV 株的异源或同源 VP4 基因，并对这些 rRV 进行了特征描述。我们发现，一种编码灵长类 VP4 的类似于鼠的 rRV 被排出，传播到未接种的同窝幼鼠中，并引起腹泻，与携带鼠 VP4 的 rRV 相当。然而，携带来自牛和猪 RV 的 VP4 的 rRV 腹泻减轻，但粪便排出量没有变化。当 VP4 来自人 RV 株时，两者的腹泻和排出都减少了。携带来自人或牛 RV 的 VP4 的 rRV 不会传播给未接种的同窝幼鼠。我们还生成了两种携带反向嵌合鼠或牛 VP4 的 rRV。两种嵌合体都能有效地复制并引起疾病，与完全具有鼠 VP4 的亲本株一样有效。这些数据表明，VP4 的遗传起源部分调节了幼鼠中的 HRR，并且 VP8和 VP5 结构域都独立地有助于发病机制和传播。 尽管已经引入了几种安全有效的减毒活疫苗，但人类 A 组轮状病毒（RV）仍然是全球婴幼儿严重急性胃肠炎的最重要原因。由于缺乏对 RV 生物学基本方面的了解，例如宿主范围限制（HRR）的遗传基础，因此难以预测性和有效地设计改进的、下一代减毒轮状病毒疫苗。在这里，我们设计了一组 VP4 单重组 RV，以在乳鼠模型中系统地研究 VP4 在复制、致病性和传播（作为 HRR 的衡量标准）中的作用。HRR 的遗传和机制基础具有重要的临床意义，因为这种限制是几种具有复制能力的人 RV 疫苗减毒的基础。此外，对 RV 发病机制和 RV 传播决定因素的更好理解可能会提高我们改进抗病毒药物和治疗开发的能力。
