ACE2-lentiviral transduction enables mouse SARS-CoV-2 infection and mapping of receptor interactions

Abstract

SARS-CoV-2 uses the human ACE2 (hACE2) receptor for cell attachment and entry, with mouse ACE2 (mACE2) unable to support infection. Herein we describe an ACE2-lentivirus system and illustrate its utility for in vitro and in vivo SARS-CoV-2 infection models. Transduction of non-permissive cell lines with hACE2 imparted replication competence, and transduction with mACE2 containing N30D, N31K, F83Y and H353K substitutions, to match hACE2, rescued SARS-CoV-2 replication. Intrapulmonary hACE2-lentivirus transduction of C57BL/6J mice permitted significant virus replication in lung epithelium. RNA-Seq and histological analyses illustrated that this model involved an acute inflammatory disease followed by resolution and tissue repair, with a transcriptomic profile similar to that seen in COVID-19 patients. hACE2-lentivirus transduction of IFNAR-/- and IL-28RA-/- mouse lungs was used to illustrate that loss of type I or III interferon responses have no significant effect on virus replication. However, their importance in driving inflammatory responses was illustrated by RNA-Seq analyses. We also demonstrate the utility of the hACE2-lentivirus transduction system for vaccine evaluation in C57BL/6J mice. The ACE2-lentivirus system thus has broad application in SARS-CoV-2 research, providing a tool for both mutagenesis studies and mouse model development.

Modeling SARS-CoV-2 Infection in Mice Using Lentiviral hACE2 Vectors Infers Two Modes of Immune Responses to SARS-CoV-2 Infection

“…These results show that exposure to SARS-CoV-2 is highly immunogenic even when the lack of hACE2 expression prevents productive SARS-CoV-2 infection and that hACE2 expression via lentiviral transduction does not trigger a significant immune response. These data support previous evidence that that exposure to SARS-CoV-2 is significantly more immunogenic than lentiviral transduction [19]. Thus, this model could be implemented as a simple methodology to generate mice models for SARS-CoV-2 infections.…”

“…In this study, we characterized the effects of SARS-CoV-2 infection on Lenti-hACE2transduced IFNAR1 −/− mice models, to achieve a more efficient SARS-CoV-2 infection and produce higher viral loads compared to wild-type mice. These mice were sensitized to SARS-CoV-2 infection by lentivirus-mediated hACE2 expression [19], as confirmed both in vitro and in vivo by detection of viral RNA, viral proteins, and infectious virion production (Figures 1-4). RNA-seq analysis of SARS-CoV-2-infected IFNAR1 −/− C57BL6 mice lungs showed that lentiviral-mediated hACE2 expression does not measurably activate cellular antiviral mechanisms, which could potentially inhibit subsequent SARS-CoV-2 infection [19].…”

“…As intracellular viral RNA induces an interferon (IFN) antiviral response, we used type 1 interferon receptor knock-out mice (IFNAR −/− ) aimed to increase SARS-CoV-2 viral loads. We implemented a two sequential steps approach, in which mice were first transduced with lentiviral vectors leading to hACE2 expression, and subsequently infected with SARS-CoV-2 [19]. Our results show that mouse lung cells that were transduced with Lenti-hACE2 in vitro or in vivo became susceptible to SARS-CoV-2 infection and enabled productive viral replication.…”

“…Coronavirus disease 2019 (COVID- 19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in China in December 2019 and rapidly spread resulting in a global pandemic. Since the outbreak of the pandemic, more than 229 million cases were reported worldwide, and over 4.7 million people had succumbed to the disease as of September 2021 (WHO).…”

“…However, transduction with AdV/AAV, which is often very immunogenic, could activate potent antiviral innate immune responses and interfere with the subsequent infection with SARS-CoV-2 [17,18]. We, therefore, implemented a lentiviral expression system to express hACE2 (Lenti-hACE2) in mice lungs since these vectors are considered moderately immunogenic [19]. As intracellular viral RNA induces an interferon (IFN) antiviral response, we used type 1 interferon receptor knock-out mice (IFNAR −/− ) aimed to increase SARS-CoV-2 viral loads.…”