RAPID: Aerosol and Direct Transmission of SARS-CoV-2 in Bats and other Animals

这项研究将增加我们对SARS-CoV-2在物种之间传播的理解，重点是蝙蝠，仓鼠和鹿鼠。这方面的知识是迫切需要的，因为SARS-CoV-2冠状病毒正在引起COVID-19大流行，并正在通过人类在全球范围内迅速传播。因此，它正在接触许多潜在的新宿主。这是有问题的，原因如下：（1）新宿主可作为中间宿主或扩增宿主，其中发生影响人畜共患病传播或发病效率的病毒突变，（2）新宿主可成为病毒的新宿主，（3）宿主可能会造成严重疾病损失，如果是牲畜，则会产生重大经济后果，如果是野生动物，则会产生生态后果，以及（4）感染更多的宿主，包括潜在的蝙蝠回溢，增加了更多新型冠状病毒产生的机会。众所周知，SARS-CoV在2002-2004年的流行中发生了突变，变得更具毒性。随着SARS-CoV-2在全球的传播，可能会出现毒力改变的反复出现。因此，增加我们对SARS-CoV-2在物种之间传播的了解至关重要。了解感染途径将有助于预防传播，并可影响疾病的临床结果。这项研究还将为博士后研究员提供一个特殊的跨学科培训机会。这项研究将研究为什么SARS-CoV-2在某些动物（如蝙蝠）中通过粪口途径传播，但在其他动物（如仓鼠、鹿鼠和人类）中可以通过空气传播。该项目将导致更好地理解为什么蝙蝠的肺部在呼吸系统通过吸入暴露于病毒时仍然未受感染。吹入的颗粒可能在上呼吸道中被过滤，肺细胞可能缺乏病毒进入所需的细胞机制[血管紧张素转换酶-2（ACE 2）受体和丝氨酸蛋白酶TMPRSS 2]，或者病毒可能进入细胞但不在细胞内复制。将在通过直接接触或吹入病毒载气溶胶接种的蝙蝠、仓鼠和鹿小鼠中进行以下实验：（1）将使用计算流体动力学对呼吸系统内吹入的雾化颗粒最有可能在呼吸期间沉积的区域进行建模。(2)将使用RNAscope生成呼吸系统和小肠内表达ACE 2、TMPRSS 2和病毒RNA的细胞图谱。(3)将这些图谱与免疫组织化学测定的病毒蛋白测量值进行比较。除了有关SARS-CoV-2传播的新知识外，该项目还将提供有关三种哺乳动物肺部生理学和细胞生物学的基本信息，并将为一名博士后研究员提供跨学科培训。该RAPID奖项由BIO综合有机系统部门的生理和结构系统集群颁发，使用冠状病毒援助，救济和经济安全（CARES）法案的资金。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research will increase our understanding of the transmission of SARS-CoV-2 between species, focusing on bats, hamsters, and deer mice. This knowledge is urgently needed because the SARS-CoV-2 coronavirus is causing the COVID-19 pandemic and is being spread rapidly and globally by humans. It is therefore coming into contact with many potential novel hosts. This is problematic for a number of reasons: (1) novel hosts could serve as intermediate or amplifying hosts in which viral mutations occur that impact efficiency for zoonotic transmission or pathogenesis, (2) novel hosts could become new reservoirs for the virus, (3) there could be a heavy disease toll on the hosts with major economic ramifications if they are livestock, or with ecological ramifications if they are wildlife, and (4) infection of more hosts, including potential spillback to bats, increases the chances of genesis of yet more novel coronaviruses. It is known that SARS-CoV mutated over the 2002-2004 epidemic to become more virulent. It is likely there will be recurrent waves of SARS-CoV-2 with altered virulence as it spreads globally. It is therefore critically important to increase our knowledge about the transmission of SARS-CoV-2 between species. Knowledge of routes of infection will help prevent transmission and can influence the clinical outcome of diseases. This research also will provide an exceptional interdisciplinary training opportunity for a postdoctoral fellow.This research will examine why transmission of SARS-CoV-2 occurs by a fecal-oral route in some animals, such as bats, but can be airborne in others, such as hamsters, deer mice and humans. The project will lead to a better understanding of why the lungs of bats remain uninfected when the respiratory system is exposed to the virus by inhalation. Insufflated particles may be filtered in the upper airways, lung cells may lack the cellular machinery required for viral entry [angiotensin-converting enzyme-2 (ACE2) receptors and the serine protease TMPRSS2], or the virus may enter cells but not replicate within them. The following experiments will be conducted in bat, hamster, and deer mice that are inoculated by direct contact or by insufflation of viral laden aerosol: (1) Regions within the respiratory system where insufflated aerosolized particles are most likely to be deposited during breathing will be modeled using computational fluid dynamics. (2) Maps of cells that express ACE2, TMPRSS2, and viral RNA within the respiratory system and the small intestine will be generated using RNAscope. (3) These maps will be compared to measurements of viral protein assayed with immunohistochemistry. In addition to new knowledge about SARS-CoV-2 transmission, this project will provide basic information about lung physiology and cell biology in three mammal species, and will provide interdisciplinary training for a post-doctoral fellow. This RAPID award is made by the Physiological and Structural Systems Cluster in the BIO Division of Integrative Organismal Systems, using funds from the Coronavirus Aid, Relief, and Economic Security (CARES) Act.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.