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Live Imaging and Quantification of Viral Infection in K18 hACE2 Transgenic Mice Using Reporter-Expressing Recombinant SARS-CoV-2
Published on: November 5, 2021
Isolation and characterization of a pangolin-borne HKU4-related coronavirus that potentially infects
Luo-Yuan Xia1, Zhen-Fei Wang1,2, Xiao-Ming Cui3,4
1Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, P. R. China.
Abstract:
We recently detected a HKU4-related coronavirus in subgenus Merbecovirus (named pangolin-CoV-HKU4-P251T) from a Malayan pangolin1. Here we report isolation and characterization of pangolin-CoV-HKU4-P251T, the genome sequence of which is closest to that of a coronavirus from the greater bamboo bat (Tylonycteris robustula) in Yunnan Province, China, with a 94.3% nucleotide identity. Pangolin-CoV-HKU4-P251T is able to infect human cell lines, and replicates more efficiently in cells that express human-dipeptidyl-peptidase-4 (hDPP4)-expressing and pangolin-DPP4-expressing cells than in bat-DPP4-expressing cells. After intranasal inoculation with pangolin-CoV-HKU4-P251, hDPP4-transgenic female mice are likely infected, showing persistent viral RNA copy numbers in the lungs. Progressive interstitial pneumonia developed in the infected mice, characterized by the accumulation of macrophages, and increase of antiviral cytokines, proinflammatory cytokines, and chemokines in lung tissues. These findings suggest that the pangolin-borne HKU4-related coronavirus has a potential for emerging as a human pathogen by using hDPP4.
Insights
A novel HKU4-related coronavirus from Malayan pangolins can infect human cells and cause pneumonia in mice. This pangolin coronavirus may pose a future risk to human health, utilizing human dipeptidyl-peptidase-4 (hDPP4) for infection.
Area of Science:
- Virology
- Zoonotic Diseases
- Coronaviruses
Background:
- Coronaviruses are a significant public health concern, with spillover events from animal reservoirs to humans posing pandemic risks.
- The HKU4-related coronavirus subgenus Merbecovirus has been detected in bats, but its potential in other wildlife reservoirs like pangolins is less understood.
Purpose of the Study:
- To isolate and characterize a novel HKU4-related coronavirus detected in Malayan pangolins.
- To investigate the infectivity and replication of this pangolin coronavirus in human and animal cell lines.
- To assess the pathogenicity of the pangolin coronavirus in a mouse model expressing human receptors.
Main Methods:
- Isolation and genomic sequencing of pangolin-CoV-HKU4-P251T.
- In vitro infection and replication assays using human, pangolin, and bat cell lines expressing specific DPP4 receptors.
- Intranasal inoculation of hDPP4-transgenic mice followed by analysis of viral load, lung pathology, and cytokine expression.
Main Results:
- The isolated virus, pangolin-CoV-HKU4-P251T, shares 94.3% nucleotide identity with a bat coronavirus.
- Pangolin-CoV-HKU4-P251T efficiently infects and replicates in human and pangolin cells expressing hDPP4 and pangolin-DPP4, respectively.
- Infection in hDPP4-transgenic mice led to persistent viral RNA in lungs, interstitial pneumonia, and elevated inflammatory markers.
Conclusions:
- Pangolin-CoV-HKU4-P251T is an HKU4-related coronavirus with the potential to infect human cells via hDPP4.
- The virus can cause lung pathology in a susceptible animal model, highlighting its potential as a zoonotic pathogen.
- Further research is warranted to understand the broader implications of pangolin coronaviruses for public health.
