蝙蝠SARS样冠状病毒WIV1利用小鼠ACE2受体研究

Interspecies Utilization of Mouse ACE2 as a Receptor for Bat SARS-like Coronavirus WIV1

严重急性呼吸综合征冠状病毒(SARS-CoV)是一种感染人类的高致病性病毒,由蝙蝠SARS样冠状病毒(SL-CoV)演化而来。血管紧张素转换酶2(ACE2)是SARS-CoV受体,影响病毒宿主范围、致病性和种间传播。先前研究表明,SARS-CoV和一些SL-CoV株(如WIV1)可以有效利用人、果子狸、蝙蝠ACE2入侵细胞,而SARS-CoV可以低效利用小鼠ACE2。啮齿动物种类多,分布广,包括多种重要的试验动物模型,不过SL-CoV利用啮齿动物ACE2的研究较少。本研究通过假病毒感染试验,比较了SARS-CoV BJ01株和SL-CoV WIV1株利用人类、果子狸、蝙蝠、小鼠ACE2及其突变体进入细胞的效率,并利用蛋白结合试验比较了BJ01和WIV1受体结合结构域(RBD)结合不同ACE2及其突变体的能力。结果显示,SL-CoV WIV1可以有效利用小鼠ACE2进入细胞,且WIV1 RBD与小鼠ACE2结合效率与人和果子狸ACE2相同,强于蝙蝠ACE2;而不同物种ACE2的L440P突变能显著降低其与BJ01及WIV1的RBD结合的能力,抑制假病毒入侵。研究结果表明,小鼠ACE2是SL-CoV WIV1的功能受体,且ACE2的L440是影响病毒入侵的关键氨基酸位点。本研究有助于进一步了解SL-CoV的受体识别、跨种传播机制,对今后类似冠状病毒的防控具有重要意义。

Severe acute respiratory syndrome coronavirus(SARS-CoV)is a highly pathogenic virus which originated from bat SARS-like coronavirus(SL-CoV)and infects humans.Angiotensin-converting enzyme 2(ACE2),the functional receptor of SARS-CoV,is a key molecular affecting SARS-CoV pathogenesis,host range,and cross-species transmission.Previous studies demonstrated that SARS-CoV and some SL-CoV strains(such as WIV1)can use human,civet,and bat ACE2 to enter cells,while SARS-CoV utilizes mouse ACE2 less effectively.Though rodents are the most diverse mammals and the most popular experimental model,the utilization of mouse ACE2 by SL-CoV has not been revealed.In the present study,pseudoviral infection experiments were conducted to compare SARS-CoV BJ01 and SL-CoV WIV1 on their ability of using human,civet,bat,mouse ACE2 and ACE2 mutants to enter cells.Meanwhile,the binding between receptor-binding domain(RBD)of the two viruses and different ACE2 was verified by protein binding experiments.The results showed that SL-CoV WIV1 can use mouse ACE2 to enter cells,and WIV1 RBD binds to mouse ACE2 as efficiently as human and civet ACE2 whereas more strongly than bat ACE2.The L440P mutation of ACE2 in different species can significantly reduce the ability of RBD binding and the efficiency of pseudovirus invasion.The studies indicate that mouse ACE2 is a functional receptor for SL-CoV WIV1 and L440 of ACE2 is a key amino acid site affecting interspecies infection.The study is helpful to further understand the receptor recognition and cross-species transmission mechanism of SL-CoV,and will be beneficial to the prevention and control of similar CoV in the future.