Immediate myeloid depot for SARS-CoV-2 in the human lung

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Abstract

In the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, epithelial populations in the distal lung expressing Angiotensin-converting enzyme 2 (ACE2) are infrequent, and therefore, the model of viral expansion and immune cell engagement remains incompletely understood. Using human lungs to investigate early host-viral pathogenesis, we found that SARS-CoV-2 had a rapid and specific tropism for myeloid populations. Human alveolar macrophages (AMs) reliably expressed ACE2 allowing both spike-ACE2–dependent viral entry and infection. In contrast to Influenza A virus, SARS-CoV-2 infection of AMs was productive, amplifying viral titers. While AMs generated new viruses, the interferon responses to SARS-CoV-2 were muted, hiding the viral dissemination from specific antiviral immune responses. The reliable and veiled viral depot in myeloid cells in the very early phases of SARS-CoV-2 infection of human lungs enables viral expansion in the distal lung and potentially licenses subsequent immune pathologies.

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  1. SciScore for 10.1101/2022.04.28.489942: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: , Zuckerberg San Francisco General Hospital) under research protocol 20-30497 approved by the University of California San Francisco Institutional Review Board.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    For selected experiments, BAL cells were treated for 2h before infection with an ACE2 blocking antibody at 10 µg/ml (AF933, R&D systems).
    ACE2
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    SARS-CoV-2 infections: Vero E6 and Vero-TMPRSS2 cells (gift from Dr. Melanie Ott) were cultured in DMEM supplemented with 10% FBS, penicillin/streptomycin, and L-glutamine (Corning) in a humidified incubator at 37°C and 5% CO2.
    Vero E6
    suggested: None
    Vero-TMPRSS2
    suggested: JCRB Cat# JCRB1818, RRID:CVCL_YQ48)
    Briefly, 10-fold dilutions of the virus stock were added to Vero cells in a 12-well plate for 1 hour, after which an overlay of 1.2% Avicel RC-581 in DMEM was added.
    Vero
    suggested: None
    This solution was used as inoculum for Vero E6 cells (SARS-CoV-2) or MDCK cells (IAV-Venus).
    MDCK
    suggested: CLS Cat# 602280/p823_MDCK_(NBL-2, RRID:CVCL_0422)
    Experimental Models: Organisms/Strains
    SentencesResources
    SARS-CoV-2 B.1.617.2 (delta) variant was acquired from the California Department of Public Health, cultured in Vero-TMPRSS2 cells.
    SARS-CoV-2 B.1.617.2
    suggested: None
    Software and Algorithms
    SentencesResources
    Confocal imaging was performed using a Nikon A1R laser scanning confocal microscope with NIS-Elements software and a 16X LWD water dipping objective.
    NIS-Elements
    suggested: None
    50 – 100 µm-thick images with a z-step of 1.5 µm were taken and analyzed using Imaris (Bitplane).
    Imaris
    suggested: None
    Data were collected using the BD LSRII Cytometer and analyzed using FlowJo version 10 (BD Biosciences).
    FlowJo
    suggested: (FlowJo, RRID:SCR_008520)
    Briefly, raw gene-expression fastqs were aligned to the GRCh38 reference genome annotated with Ensembl v85, and Lipid Hashtag fastqs were processed to count the incidences of each expected index per cell.
    Ensembl
    suggested: None
    Data quality control and normalization: The gene expression count matrices were normalized, and variance stabilized using negative binomial regression using the scTransform algorithm21 in the Seurat package.
    Seurat
    suggested: (SEURAT, RRID:SCR_007322)
    Statistical analyses: Statistical analysis was performed using GraphPad Prism v7.0e.
    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: We did not find any issues relating to colormaps.


    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.

    Results from scite Reference Check: We found no unreliable references.


    About SciScore

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