Mechanism of Hepatitis E Virus Replication and Pathogenesis

描述（由申请人提供）：戊型肝炎病毒（HEV）是人类戊型肝炎的病原体，是发展中国家的一个重要公共卫生问题，在美国和其他工业化国家也流行。孕妇与戊型肝炎病毒感染相关的死亡率高达28%。由于缺乏细胞培养和实用的动物模型系统，人们对戊型肝炎病毒的复制机制和发病机制知之甚少，目前还没有戊型肝炎疫苗。我们最近从猪和鸡身上发现的猪和禽戊型肝炎病毒，以及动物戊型肝炎病毒株跨物种感染的能力，为戊型肝炎病毒的研究开辟了新的途径。戊型肝炎现在是一种公认的人畜共患疾病，猪（可能还有其他动物物种）是已知的宿主。该提案基于我们最近对猪和禽HEV的发现，猪和鸡HEV模型的建立，人类，猪和禽HEV的感染性cDNA克隆的构建，以及先前NIH对HEV （AI01653, AI46505）的两个奖项（现已过期）支持HEV复制的细胞系的鉴定。PI决定不提交竞争性的续期，这样他就可以通过提交一个新的提案来结合过期的奖项的方向，扩大他的HEV研究范围。长期目标是通过使用猪、鸡和非人灵长类动物作为模型，以及使用禽-猪、禽-人和猪-人HEV嵌合体来确定对这些过程具有重要功能的基因组区域，从而了解HEV复制、发病机制和跨物种感染的机制。在这个建议中，我们的目标是：(1)。确定高变区（HVR）在HEV复制和发病机制中的作用；(2)。了解HEV跨种感染和宿主易感性的分子基础；和(3)。精细绘制HEV衣壳蛋白上对HEV衰减很重要的氨基酸残基。这将通过使用包括细胞培养、分子生物学和动物研究在内的标准技术来完成。这些研究将极大地促进我们对HEV的复制、发病机制和跨种感染机制的理解，并将为未来的疫苗开发提供有用的信息。公共卫生相关性：对戊型肝炎基本生物学和发病机制的缺乏极大地阻碍了戊型肝炎疫苗的开发。从该项目获得的信息将有助于了解HEV复制和发病机制，并有助于制定有效的预防和控制策略（如减毒活疫苗），以对抗这一重要但研究极为不足的人类病原体。

DESCRIPTION (provided by applicant): Hepatitis E virus (HEV), the causative agent of human hepatitis E, is an important public health problem in developing countries, and is also endemic in the United States and other industrialized countries. The mortality rate associated with HEV infection is up to 28% in pregnant women. Due to the lack of a cell culture and a practical animal model system, the mechanisms of HEV replication and pathogenesis are poorly understood and a vaccine against hepatitis E is still not available. Our recent discoveries of swine and avian hepatitis E viruses from pigs and chickens and the demonstrated abilities of cross-species infections by the animal HEV strains have opened up new avenues for HEV research. Hepatitis E now is a recognized zoonotic disease, and pigs (and maybe other animal species) are known reservoirs. This proposal is based on our recent discoveries of swine and avian HEVs, establishment of pig and chicken models for HEV, construction of infectious cDNA clones of human, swine and avian HEVs, and identification of cell lines supporting HEV replication resulting from two prior NIH awards on HEV (AI01653, AI46505) which have now expired. The PI decided not to submit competing renewals so that he can combine the directions of the expired awards and expand the scope of his HEV research by submitting a single new proposal. The long-term objectives are to understand the mechanisms of HEV replication, pathogenesis and cross-species infection by using pigs, chickens and non-human primates as models, and by using avian-swine, avian-human and swine-human HEV chimeras to identify genomic regions that are functionally important for these processes. In this proposal, we aim to: (1). Determining the role(s) of the hypervariable region (HVR) in HEV replication and pathogenesis; (2). Understand the molecular basis of HEV cross-species infection and host susceptibility; and (3). Fine-map the amino acid residue(s) on HEV capsid protein that are important for HEV attenuation. This will be accomplished by using standard techniques including cell cultures, molecular biology, and animal studies. The proposed studies will significantly advance our understanding of the mechanisms of HEV replication, pathogenesis and cross- species infection, and will provide useful information for future vaccine development. PUBLIC HEALTH RELEVANCE: The lack of knowledge on HEV basic biology and pathogenesis has greatly hindered the development of a vaccine against HEV. The information gained from this project will help understand the mechanisms of HEV replication and pathogenesis, and help devise effective preventive and control strategies (such as a live-attenuated vaccine) against this important but extremely understudied human pathogen.