BSL2-compliant lethal mouse model of SARS-CoV-2 and variants of concern to evaluate therapeutics targeting the Spike protein

Since first reported in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly acquiring mutations, particularly in the spike protein, that can modulate pathogenicity, transmission and antibody evasion leading to successive waves of COVID19 infections despite an unprecedented mass vaccination necessitating continuous adaptation of therapeutics. Small animal models can facilitate understanding host-pathogen interactions, target selection for therapeutic drugs, and vaccine development, but availability and cost of studies in BSL3 facilities hinder progress. To generate a BSL2-compatibl

BSL2-compliant lethal mouse model of SARS-CoV-2 and variants of concern to evaluate therapeutics targeting the Spike protein

Since first reported in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly acquiring mutations, particularly in the spike protein, that can modulate pathogenicity, transmission and antibody evasion leading to successive waves of COVID19 infections despite an unprecedented mass vaccination necessitating continuous adaptation of therapeutics. Small animal models can facilitate understanding host-pathogen interactions, target selection for therapeutic drugs, and vaccine development, but availability and cost of studies in BSL3 facilities hinder progress. To generate a BSL2-compatible in vivo system that specifically recapitulates spike protein mediated disease we used replication competent, GFP tagged, recombinant Vesicular Stomatitis Virus where the VSV glycoprotein was replaced by the SARS-CoV-2 spike protein (rVSV-SARS2-S). We show that infection requires hACE2 and challenge of neonatal but not adult, K18-hACE2 transgenic mice (hACE2tg) leads to productive infection of the lungs and brains. Although disease progression was faster in SARS-CoV-2 infected mice, infection with both viruses resulted in neuronal infection and encephalitis with increased expression of Interferon-stimulated Irf7, Bst2, Ifi294, as well as CxCL10, CCL5, CLC2, and LILRB4, and both models were uniformly lethal. Further, prophylactic treatment targeting the Spike protein (Receptor Binding Domain) with antibodies resulted in similar levels of protection from lethal infection against rVSV-SARS2-S and SARS-CoV-2 viruses. Strikingly, challenge of neonatal hACE2tg mice with SARS-CoV-2 Variants of Concern (SARS-CoV-2-α, -β, ϒ, or Δ) or the corresponding rVSV-SARS2-S viruses (rVSV-SARS2-Spike-α, rVSV-SARS2-Spike-β, rVSV-SARS2-Spike-ϒ or rVSV-SARS2-Spike-Δ) resulted in increased lethality, suggesting that the Spike protein plays a key role in determining the virulence of each variant. Thus, we propose that rVSV-SARS2-S virus can be used to understand the effect of changes to SARS-CoV-2 spike protein on infection and to evaluate existing or experimental therapeutics targeting spike protein of current or future VOC of SARS-CoV-2 under BSL-2 conditions

Pain neuroimaging in humans: a primer for beginners and non-imagers

The field of human pain neuroimaging has exploded in the last two decades. During this time, the broader neuroimaging community has continued to investigate and refine methods. Another key to progress is exchange with clinicians and pain scientists working with other model systems and approaches. These collaborative efforts require that non-imagers be able to evaluate and assess the evidence provided in these papers. Likewise, new trainees must design rigorous and reliable pain imaging experiments. Here, we provide a guideline for designing, reading, evaluating, analyzing, and reporting results of a pain neuroimaging experiment, with a focus on functional and structural MRI. We focus in particular on considerations that are unique to neuroimaging studies of pain in humans, including study design and analysis, inferences that can be drawn from these studies, and the strengths and limitations of the approach. This article provides an overview of the concepts and considerations of structural and functional MRI neuroimaging studies. The primer is written for those who are not familiar with brain imaging. We review key concepts related to recruitment and study sample, experimental design, data analysis and data interpretation. [Abstract copyright: Copyright © 2018. Published by Elsevier Inc.

Therapeutic proteins don’t modify the LLOD in RAW—BLUE cells.

<p>RAW-BLUE cells were stimulated with indicated concentration of (<b>A</b>) Pam3CSK4 (<b>B</b>) Zymosan in the presence or absence of erythropoietin (1000IU/mL) and IFNβ (1000IU/mL) for 24h. NF-κB activation was assessed in the culture supernatant as described in materials and methods. Each point represents mean ± SD of triplicate cell culture.</p

HEK-BLUE-hTLR transfectants detect trace levels of impurities in therapeutic products.

<p>(<b>A-B</b>) A total of 5x10⁴ HEK-BLUE-hTLR2 (<b>C-D)</b> 2.5x10⁴ HEK-BLUE-hTLR4 were cultured for 24h with increasing concentrations of Pam3CSK4 and Endotoxin in the presence of 0-1000IU/mL of EPO and IFNβ to assess the sensitivity of the cell lines and the product interference. NF-κB activation was measured from the supernatant after the addition of QUANTI-Blue. Each point represents mean ± SD of triplicate cell culture.</p

Multiple impurities do not modify the LLOD for each individual impurity.

<p>MM6 cells were cultured in the presence of increasing concentration of (<b>A</b>) Endotoxin and FSL-1 (<b>B</b>) Endotoxin and zymosan alone or in combination. mRNA level of IL-6 was quantified at 24h by q-RT-PCR. Each point represents mean ± SD of triplicate cell culture.</p

Limit of detection to PRR ligands in PBMC and monocyte/macrophage cell lines.

<p>PBMC, RAW-BLUE, THP-1 and MM6 cells were stimulated with the indicated concentration of (<b>A-D</b>) Endotoxin, Pam3CSK4 and FSL-1, (<b>E-H</b>) Poly I:C and Flagellin, (<b>I-K</b>) Imiquimod, CLO75 and CpG (<b>L-O</b>) zymosan and MDP. Levels of IL-8 mRNA (relative expression vs media), NF-κB activation (OD 620) and luciferase activity (RLU) were measured as described in materials and methods. All samples were tested in triplicate. Data points represent mean ± SD. (*p<0.05 vs media control). Red points show the limit of detection for each individual IIRMIs.</p

Limit of detection for PPR ligands by monocyte/macrophage cell lines and PBMC.

<p>Limit of detection for PPR ligands by monocyte/macrophage cell lines and PBMC.</p

Impact of immunomodulatory proteins on the LLOD for PRR ligands in MM6 cells.

<p>MM6 cells were placed in culture with EPO (1000IU/mL) together with increasing concentration of (<b>A-B</b>) Endotoxin and (<b>C-D</b>) FSL for 24h. Messenger RNA expression of IL-6 and IL-8 was determined by q-RT-PCR. MM6 cells were placed in culture with IFNβ (1000IU/mL) together with increasing concentration of (<b>E-F</b>) Endotoxin and (<b>G-H</b>) FSL for 24h. Messenger RNA expression of IL-6 and IL-8 was determined by q-RT-PCR. A representative of 2 independent experiments with similar results is shown. (*p<0.05 vs EPO alone or IFNβ alone).</p