The Genetic Diversity Mice Models in SARS-CoV-2 Infection (preprint)

The SARS-CoV-2 has led to a worldwide health crisis. The ACE2 has been identified as the entry receptor in a species-specific manner. Classic laboratory mice were insusceptible since the virus cannot use murine ACE2 orthologue. Animal models rely on gene modification on the virus or the host. However, these mice were restricted in limited genetic backgrounds and did not support natural infection. Here we showed two wild-type inbred lines (CAST and FEW) from Genetic Diversity mice supported authentic SARS-CoV-2 infection, and developed mild to moderate interstitial pneumonia, along with infiltrating inflammatory cells. Particularly, FEW featured age-dependent damages, while CAST charactered by pulmonary fibrosis. Genome and transcriptome comparative analysis suggested the mutated ACE2 was not responsible for SARS-CoV-2 infection in CAST and FEW, and the differential gene expressions in immune response and immune cell may be risk factors for the infection. In summary, the GD mice, derived from the multi-parental panel, provided promising murine models for exploring sophisticated pathogenesis in SARS-CoV-2.

Differential transcriptomic landscapes of multiple organs from SARS-CoV-2 early infected rhesus macaques (preprint)

SARS-CoV-2 infection causes complicated clinic manifestations with variable multi-organ injuries, however, the underlying mechanism, in particular immune responses in different organs, remains elusive. In this study, comprehensive transcriptomic alterations of 14 tissues from rhesus macaque infected with SARS-CoV-2 were analyzed. Compared to normal controls, SARS-CoV-2 infection resulted in dysregulation of genes involving diverse functions in various tissues/organs examined, with drastic transcriptomic changes in cerebral cortex and right ventricle. Intriguingly, cerebral cortex exhibited a hyperinflammatory state evidenced by significant upregulation of inflammation response-related genes. Meanwhile, expressions of coagulation, angiogenesis and fibrosis factors were also up-regulated in cerebral cortex. Neuronal receptor NRP1 expression showed a significant induction by SARS-CoV-2 in cerebral cortex, which might be responsible for a higher infectivity and consequent inflammatory response. Overall, our study depicts a multi-tissue/organ transcriptomic landscapes of rhesus macaque with early infection of SARS-CoV-2, and provides important insights into the mechanistic basis for COVID-19-associated clinical complications.

Reinfection could not occur in SARS-CoV-2 infected rhesus macaques (preprint)

A global pandemic of Corona Virus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is ongoing spread. It remains unclear whether the convalescing patients have a risk of reinfection. Rhesus macaques were rechallenged with SARS-CoV-2 during an early recovery phase from initial infection characterized by weight loss, interstitial pneumonia and systemic viral dissemination mainly in respiratory and gastrointestinal tracts. The monkeys rechallenged with the identical SARS-CoV-2 strain have failed to produce detectable viral dissemination, clinical manifestations and histopathological changes. A notably enhanced neutralizing antibody response might contribute the protection of rhesus macaques from the reinfection by SARS-CoV-2. Our results indicated that primary SARS-CoV-2 infection protects from subsequent reinfection. One Sentence SummaryNeutralizing antibodies against SARS-CoV-2 might protect rhesus macaques which have undergone an initial infection from reinfection during early recovery days.

Rhesus macaques can be effectively infected with SARS-CoV-2 via ocular conjunctival route (preprint)

The outbreak of Corona Virus Disease 2019 caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) is highly transmitted. The potential extra-respiratory transmission routes remain uncertain. Five rhesus macaques were inoculated with 1x106 TCID50 of SARS-CoV-2 via conjunctival (CJ), intratracheal (IT), and intragastric (IG) routes, respectively. Remarkably, the CJ inoculated-macaques developed mild interstitial pneumonia and viral load was detectable in the conjunctival swabs at 1 days post-inoculation (dpi). Only via IT inoculation, viral load was detected in the anal swab at 1-7 dpi and macaque showed weight loss. However, viral load was undetectable after IG inoculation. Comparatively, viral load was higher in the nasolacrimal system but lesions of lung were relatively mild and local via CJ inoculation compared with that via IT inoculation, demonstrating distinct characteristics of virus dispersion. Both the two routes affected the alimentary tract. Therefore the clinicians need to protect eye while working with patients.

The Pathogenicity of 2019 Novel Coronavirus in hACE2 Transgenic Mice (preprint)

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) caused the Corona Virus Disease 2019 (COVID-19) cases in China has become a public health emergency of international concern (PHEIC). Based on angiotensin converting enzyme 2 (ACE2) as cell entry receptor of SARS-CoV, we used the hACE2 transgenic mice infected with SARS-CoV-2 to study the pathogenicity of the virus. Weight loss and virus replication in lung were observed in hACE2 mice infected with SARS-CoV-2. The typical histopathology was interstitial pneumonia with infiltration of significant lymphocytes and monocytes in alveolar interstitium, and accumulation of macrophages in alveolar cavities. Viral antigens were observed in the bronchial epithelial cells, alveolar macrophages and alveolar epithelia. The phenomenon was not found in wild type mice with SARS-CoV-2 infection. The pathogenicity of SARS-CoV-2 in hACE2 mice was clarified and the Kochs postulates were fulfilled as well, and the mouse model may facilitate the development of therapeutics and vaccines against SARS-CoV-2.