Human coronaviruses (HCoVs) are important pathogens that cause upper respiratory tract infections and have neuroinvasive abilities; however, little is known about the dynamic infection process of CoVs in vivo, and there are currently no specific antiviral drugs to prevent or treat HCoV infection. Here, we verified the replication ability and pathogenicity of a reporter HCoV-OC43 strain expressing Renilla luciferase (Rluc; rOC43-ns2DelRluc) in mice with different genetic backgrounds (C57BL/6 and BALB/c). Additionally, we monitored the spatial and temporal progression of HCoV-OC43 through the central nervous system (CNS) of live BALB/c mice after intranasal or intracerebral inoculation with rOC43-ns2DelRluc. We found that rOC43-ns2DelRluc was fatal to suckling mice after intranasal inoculation, and that viral titers and Rluc expression were detected in the brains and spinal cords of mice infected with rOC43-ns2DelRluc. Moreover, viral replication was initially observed in the brain by non-invasive bioluminescence imaging before the infection spread to the spinal cord of BALB/c mice, consistent with its tropism in the CNS. Furthermore, the Rluc readout correlated with the HCoV replication ability and protein expression, which allowed quantification of antiviral activity in live mice. Additionally, we validated that chloroquine strongly inhibited rOC43-ns2DelRluc replication in vivo. These results provide new insights into the temporal and spatial dissemination of HCoV-OC43 in the CNS, and our methods provide an extremely sensitive platform for evaluating the efficacy of antiviral therapies to treat neuroinvasive HCoVs in live mice.

中文翻译：

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HCoV-OC43感染和活小鼠中枢神经系统治疗的非侵入性生物发光成像。

人冠状病毒（HCoV）是引起上呼吸道感染并具有神经侵袭能力的重要病原体。然而，关于冠状病毒在体内的动态感染过程知之甚少，目前还没有用于预防或治疗HCoV感染的特异性抗病毒药物。在这里，我们验证了具有不同遗传背景（C57BL / 6和BALB / c）的小鼠中表达海肾荧光素酶（Rluc； rOC43-ns2DelRluc）的报道型HCoV-OC43菌株的复制能力和致病性。此外，我们在鼻内或脑内接种了rOC43-ns2DelRluc后，通过活BALB / c小鼠的中枢神经系统（CNS）监测了HCoV-OC43的时空进程。我们发现鼻内接种rOC43-ns2DelRluc对乳鼠具有致命性，并且在感染了rOC43-ns2DelRluc的小鼠的大脑和脊髓中检测到病毒滴度和Rluc表达。而且，在感染传播到BALB / c小鼠的脊髓之前，最初是通过无创生物发光成像在大脑中观察到病毒复制，这与其在CNS中的向性相一致。此外，Rluc读数与HCoV复制能力和蛋白质表达相关，从而可以定量活小鼠的抗病毒活性。此外，我们验证了氯喹在体内强烈抑制rOC43-ns2DelRluc复制。这些结果为HCoV-OC43在中枢神经系统中的时空分布提供了新的见识，我们的方法为评估抗病毒疗法在活小鼠中治疗神经侵袭性HCoV的有效性提供了极为敏感的平台。