SARS-CoV-2 spike protein binds to bacterial lipopolysaccharide and boosts proinflammatory activity

  1. Ganna Petruk
  2. Manoj Puthia
  3. Jitka Petrlova
  4. Firdaus Samsudin
  5. Ann-Charlotte Strömdahl
  6. Samuel Cerps
  7. Lena Uller
  8. Sven Kjellström
  9. Peter J Bond
  10. and Artur Schmidtchen

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Abstract

There is a link between high lipopolysaccharide (LPS) levels in the blood and the metabolic syndrome, and metabolic syndrome predisposes patients to severe COVID-19. Here, we define an interaction between SARS-CoV-2 spike (S) protein and LPS, leading to aggravated inflammation in vitro and in vivo. Native gel electrophoresis demonstrated that SARS-CoV-2 S protein binds to LPS. Microscale thermophoresis yielded a KD of ∼47 nM for the interaction. Computational modeling and all-atom molecular dynamics simulations further substantiated the experimental results, identifying a main LPS-binding site in SARS-CoV-2 S protein. S protein, when combined with low levels of LPS, boosted nuclear factor-kappa B (NF-κB) activation in monocytic THP-1 cells and cytokine responses in human blood and peripheral blood mononuclear cells, respectively. The in vitro inflammatory response was further validated by employing NF-κB reporter mice and in vivo bioimaging. Dynamic light scattering, transmission electron microscopy, and LPS-FITC analyses demonstrated that S protein modulated the aggregation state of LPS, providing a molecular explanation for the observed boosting effect. Taken together, our results provide an interesting molecular link between excessive inflammation during infection with SARS-CoV-2 and comorbidities involving increased levels of bacterial endotoxins.

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  1. Version published to 10.1093/jmcb/mjaa067
  2. ScreenIT

    SciScore for 10.1101/2020.06.29.175844: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIACUC: Ethics statement: All animal experiments are performed according to Swedish Animal Welfare Act SFS 1988:534 and were approved by the Animal Ethics Committee of Malmö/Lund, Sweden.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Primary antibodies against the His-tag (1:2000, Invitrogen) were followed by secondary HRP conjugated antibody (1:2000, Dako, Denmark), for detection of S protein.
    His-tag
    suggested: None
    Experimental Models: Organisms/Strains
    SentencesResources
    In another set of experiments, 2 μg of SARS-Cov-2 S protein were incubated with 0.25 mg/ml of LPS and Lipid A from E. coli, LPS from P. aeruginosa, LTA and PGN from S. aureus, and zymosan from S. cerevisiae.
    P . aeruginosa
    suggested: None
    Software and Algorithms
    SentencesResources
    The image was obtained using a Gel Doc Imager (Bio-Rad Laboratories,
    Bio-Rad Laboratories
    suggested: (Bio-Rad Laboratories, RRID:SCR_008426)
    Evaluation of the spectra was performed with Xcalibur v 2.0.7. software (from Thermo Fisher Scientific, San José, CA).
    Xcalibur
    suggested: (Thermo Xcalibur, RRID:SCR_014593)
    Statistical analysis, as indicated in each figure legend, were performed using GraphPad Prism software v8.
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: Please consider improving the rainbow (“jet”) colormap(s) used on page 23. At least one figure is not accessible to readers with colorblindness and/or is not true to the data, i.e. not perceptually uniform.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.06.29.175844v1 on bioRxiv