Non-invasive bioluminescence imaging of HCoV-OC43 infection and therapy in the central nervous system of live mice

Abstract

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.

Human Coronaviruses and Other Respiratory Viruses: Underestimated Opportunistic Pathogens of the Central Nervous System?

“…These results, together with data harvested with the use of microfluidic devices (Xona microfluidic), helped to elaborate a putative model of propagation adapted from Tomishima and Enquist [291], in which infectious HCoV-OC43 could either be assembled in the cell body or at different points along the axon using the anterograde axonal transport to propagate between neurons or from neurons to glial cells surrounding neurons in the CNS (Figure 2). Furthermore, based on previous data using different mutant recombinant viruses harboring mutation in the S protein [266,268,269] and making use of a luciferase expressing recombinant HCoV-OC43 [292][293][294], we are now showing that the rate and success of virus propagation towards the spinal cord, in part through the neuron-to-neuron pathway, correlates with the exacerbation of neurovirulence (Figure 3). [269] and adapted from Tomishima and Enquist [291].…”

COVID-19 virus may have neuroinvasive potential and cause neurological complications: a perspective review

“…Data from clinical and animal studies have shown that CoVs can cross the blood-brain barrier (BBB) and exert neuroinvasive properties (Cabirac et al 1994;Cavanagh 2005;Desforges et al 2013;Li et al 2016b;Niu et al 2020;Talbot et al 2011;). The precise mechanisms of penetration into the CNS have not been fully understood.…”

Neurological Involvement of Coronavirus Disease 2019: A Systematic Review

“…[2] Of these, SARS-CoV-1, MERS-CoV, HCoV-OC43, and HCoV-229E are associated with neurological complications. [3] Large territory stroke, polyneuropathy, myopathy, seizures and status epilepticus were reported in patients with SARS CoV-1 outbreak in 2002/2003. [4,5] In-vivo, intranasal inoculation of the SARS-CoV-1 led to severe neuronal loss at the brainstem and speci cally the respiratory center at the medulla.…”