SARS-CoV-2 uses metabotropic glutamate receptor subtype 2 as an internalization factor to infect cells

Jinliang Wang,Chong Wang,Xijun He,Xiao Yang,Ziruo Sun,Jinying Ge,Ronghong Hua,Zhigao Bu,Gongxun Zhong,Xinxin Wang,Zhiyuan Wen,Xijun Wang,Guan Yang,Lei Shuai,Weiye Chen,Jie Luo,Renqiang Liu

doi:10.1038/s41421-021-00357-z

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses angiotensin-converting enzyme 2 (ACE2) as a binding receptor to enter cells via clathrin-mediated endocytosis (CME). However, receptors involved in other steps of SARS-CoV-2 infection remain largely unknown. Here, we found that metabotropic glutamate receptor subtype 2 (mGluR2) is an internalization factor for SARS-CoV-2. Our results show that mGluR2 directly interacts with the SARS-CoV-2 spike protein and that knockdown of mGluR2 decreases internalization of SARS-CoV-2 but not cell binding. Further, mGluR2 is uncovered to cooperate with ACE2 to facilitate SARS-CoV-2 internalization through CME and mGluR2 knockout in mice abolished SARS-CoV-2 infection in the nasal turbinates and significantly reduced viral infection in the lungs. Notably, mGluR2 is also important for SARS-CoV spike protein- and Middle East respiratory syndrome coronavirus spike protein-mediated internalization. Thus, our study identifies a novel internalization factor used by SARS-CoV-2 and opens a new door for antiviral development against coronavirus infection.

Highlights

A novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the causative pathogen of coronavirus disease 2019 (COVID-19)[1]
Results metabotropic glutamate receptor subtype 2 (mGluR2) is required for SARS-CoV-2 infection and directly interacts with the S protein To test whether mGluR2 is needed for SARS-CoV-2 infection, we first tested mGluR2 expression in Vero-E6 cells and Caco-2 cells, which are susceptible to SARSCoV-2 infection. mGluR2 was labeled on the membrane of the two cell lines and examined by using flow cytometry
The findings that mGluR2 directly interacts with Angiotensin-converting enzyme 2 (ACE2), that mGluR2, ACE2, and SARS-CoV-2 colocalize in cells, and that knockdown of mGluR2 affects SARS-CoV-2 internalization but not binding indicate that mGluR2 cooperates with ACE2 to mediate SARS-CoV-2 internalization. mGluR2 is important for SARS-CoV and MERS-CoV S protein-mediated internalization, suggesting that mGluR2 likely plays a conserved role in the internalization of coronaviruses, at least betacoronaviruses

Summary

Introduction

A novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the causative pathogen of coronavirus disease 2019 (COVID-19)[1]. Angiotensin-converting enzyme 2 (ACE2) has been well documented as a receptor for SARS-CoV-2, which directly interacts with the SARS-CoV-2 spike (S) protein and renders cells and mice susceptible to SARS-CoV-2 infection[1,10,11,12]. It remains largely unclear whether SARS-CoV-2 uses other receptors. Recent studies have identified several proteins or nonprotein molecules that facilitate SARS-CoV-2 entry into cells. Dendritic cell (DC)-specific intercellular adhesion molecule-3-grabbing non-integrin, and liver/lymph node-specific intracellular adhesion

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Conclusion