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Cross-Linking Mass Spectrometry Uncovers Interactions Between High-Density Lipoproteins and the SARS-CoV-2 Spike
Sean A Burnap1, Ana Maria Ortega-Prieto2, Jose M Jimenez-Guardeño2
1Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK; The Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, UK; King's College London British Heart Foundation Centre, School of Cardiovascular Medicine and Sciences, London, UK.
Insights
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins interact with apolipoproteins on high-density lipoprotein (HDL) in COVID-19 patients. These interactions do not affect viral replication or infectivity.
Area of Science:
- Biochemistry
- Virology
- Immunology
Background:
- High-density lipoprotein (HDL) levels decrease in COVID-19 patients, correlating with poor outcomes.
- The role of lipoproteins in coronavirus (CoV) infections is not well understood.
- Lipoproteins are crucial for the hepatitis C virus lifecycle.
Purpose of the Study:
- To identify circulating protein interactors of the SARS-CoV-2 spike glycoprotein.
- To investigate the interaction between SARS-CoV-2 spike and HDL components in COVID-19 patients.
Main Methods:
- Cross-linking mass spectrometry (XL-MS) was used to analyze plasma from COVID-19 patients and isolated HDL.
- Immunoprecipitation-mass spectrometry (IP-MS) validated interactions in cellular models.
- Data-driven structural modeling elucidated binding mechanisms.
Main Results:
- XL-MS identified HDL protein networks in COVID-19 plasma, including serum amyloid proteins binding to apolipoprotein D (ApoD).
- Direct interactions were found between SARS-CoV-2 spike and ApoD, ApoA1, and ApoC3 on HDL.
- ApoD and SARS-CoV-2 spike were found to interact with membrane-associated progesterone receptor component 1.
- ApoD was determined to interact within the spike's receptor-binding domain, but ApoD overexpression did not impact viral replication or infectivity.
Conclusions:
- SARS-CoV-2 spike protein binds to apolipoproteins on HDL.
- These specific HDL-spike protein interactions do not influence SARS-CoV-2 infectivity or replication.
Abstract:
High-density lipoprotein (HDL) levels are reduced in patients with coronavirus disease 2019 (COVID-19), and the extent of this reduction is associated with poor clinical outcomes. While lipoproteins are known to play a key role during the life cycle of the hepatitis C virus, their influence on coronavirus (CoV) infections is poorly understood. In this study, we utilize cross-linking mass spectrometry (XL-MS) to determine circulating protein interactors of the severe acute respiratory syndrome (SARS)-CoV-2 spike glycoprotein. XL-MS of plasma isolated from patients with COVID-19 uncovered HDL protein interaction networks, dominated by acute-phase serum amyloid proteins, whereby serum amyloid A2 was shown to bind to apolipoprotein (Apo) D. XL-MS on isolated HDL confirmed ApoD to interact with SARS-CoV-2 spike but not SARS-CoV-1 spike. Other direct interactions of SARS-CoV-2 spike upon HDL included ApoA1 and ApoC3. The interaction between ApoD and spike was further validated in cells using immunoprecipitation-MS, which uncovered a novel interaction between both ApoD and spike with membrane-associated progesterone receptor component 1. Mechanistically, XL-MS coupled with data-driven structural modeling determined that ApoD may interact within the receptor-binding domain of the spike. However, ApoD overexpression in multiple cell-based assays had no effect upon viral replication or infectivity. Thus, SARS-CoV-2 spike can bind to apolipoproteins on HDL, but these interactions do not appear to alter infectivity.
