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

  1. Ganna Petruk
  2. Manoj Puthia
  3. Jitka Petrlova
  4. Ann-Charlotte Strömdahl
  5. Sven Kjellström
  6. Artur Schmidtchen

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Abstract

There is a well-known and established link between high lipopolysaccharide (LPS) levels in blood and the metabolic syndrome (MS). MS is a risk factor for developing severe COVID-19 and acute respiratory distress syndrome (ARDS). Here we define an interaction between SARS-CoV-2 Spike (S) protein and LPS and its link to aggravated inflammation in vitro and in vivo. Electrophoresis under native conditions demonstrated that SARS-CoV-2 S protein binds to Escherichia coli LPS, forming high molecular weight aggregates. Microscale thermophoresis analysis further defined the interaction, having a K D of ~47 nM, similar to the observed affinity between LPS and the human receptor CD14. Moreover, S protein, when combined with low levels of LPS, boosted nuclear factor-kappa B (NF-κB) and cytokine responses in monocytic THP-1 cells and human blood, respectively. In an experimental model of localized inflammation, employing NF-κB reporter mice and in vivo bioimaging, S protein in conjunction with LPS significantly increased the inflammatory response when compared with S protein and LPS alone. Apart from providing information on LPS as a ligand for S protein, our results are of relevance for studies on comorbidities involving bacterial endotoxins, such as the MS, or co-existing acute and chronic infections in COVID-19 patients.

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  1. 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.

  2. Version published to 10.1101/2020.06.29.175844 on bioRxiv