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1.
Sci Rep ; 12(1): 696, 2022 01 13.
Article in English | MEDLINE | ID: covidwho-1621270

ABSTRACT

Despite encouraging preclinical data, therapies to reduce ARDS mortality remains a globally unmet need, including during the COVID-19 pandemic. We previously identified extracellular nicotinamide phosphoribosyltransferase (eNAMPT) as a novel damage-associated molecular pattern protein (DAMP) via TLR4 ligation which regulates inflammatory cascade activation. eNAMPT is tightly linked to human ARDS by biomarker and genotyping studies in ARDS subjects. We now hypothesize that an eNAMPT-neutralizing mAb will significantly reduce the severity of ARDS lung inflammatory lung injury in diverse preclinical rat and porcine models. Sprague Dawley rats received eNAMPT mAb intravenously following exposure to intratracheal lipopolysaccharide (LPS) or to a traumatic blast (125 kPa) but prior to initiation of ventilator-induced lung injury (VILI) (4 h). Yucatan minipigs received intravenous eNAMPT mAb 2 h after initiation of septic shock and VILI (12 h). Each rat/porcine ARDS/VILI model was strongly associated with evidence of severe inflammatory lung injury with NFkB pathway activation and marked dysregulation of the Akt/mTORC2 signaling pathway. eNAMPT neutralization dramatically reduced inflammatory indices and the severity of lung injury in each rat/porcine ARDS/VILI model (~ 50% reduction) including reduction in serum lactate, and plasma levels of eNAMPT, IL-6, TNFα and Ang-2. The eNAMPT mAb further rectified NFkB pathway activation and preserved the Akt/mTORC2 signaling pathway. These results strongly support targeting the eNAMPT/TLR4 inflammatory pathway as a potential ARDS strategy to reduce inflammatory lung injury and ARDS mortality.


Subject(s)
Acute Chest Syndrome/metabolism , Mechanistic Target of Rapamycin Complex 2/metabolism , NF-kappa B/metabolism , Nicotinamide Phosphoribosyltransferase/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/physiology , Animals , Antibodies, Neutralizing/metabolism , Biomarkers/metabolism , COVID-19/metabolism , Disease Models, Animal , Inflammation/metabolism , Lipopolysaccharides/metabolism , Lung/metabolism , Male , Rats , Rats, Sprague-Dawley , SARS-CoV-2/pathogenicity , Swine
3.
Mol Cell Biochem ; 476(1): 93-107, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-737128

ABSTRACT

Mesenchymal stem cells (MSCs) can alleviate acute respiratory distress syndrome (ARDS), but the mechanisms involved are unclear, especially about their specific effects on cellular mitochondrial respiratory function. Thirty mice were allocated into the Control, LPS, and LPS + Bone marrow mesenchymal stem cell (BMSC) group (n = 10/group). Mouse alveolar epithelial cells (MLE-12) and macrophage cells (RAW264.7) were divided into the same groups. Pathological variation, inflammation-related factors, reactive oxygen species (ROS), ATP levels, and oxygen consumption rate (OCR) were analyzed. Pathologic features of ARDS were observed in the LPS group and were significantly alleviated by BMSCs. The trend in inflammation-related factors among the three groups was the LPS group > LPS + BMSC group > Control group. In the MLE-12 co-culture system, IL-6 was increased in the LPS group but not significantly reduced in the LPS + BMSC group. In the RAW264.7 co-culture system, IL-1ß, TNF-α, and IL-10 levels were all increased in the LPS group, IL-1ß and TNF-α levels were reduced by BMSCs, while IL-10 level kept increasing. ROS and ATP levels were increased and decreased respectively in both MLE-12 and RAW264.7 cells in the LPS groups but reversed by BMSCs. Basal OCR, ATP-linked OCR, and maximal OCR were lower in the LPS groups. Impaired basal OCR and ATP-linked OCR in MLE-12 cells were partially restored by BMSCs, while impaired basal OCR and maximal OCR in RAW264.7 cells were restored by BMSCs. BMSCs improved the mitochondrial respiration dysfunction of macrophages and alveolar epithelial cells induced by LPS, alleviated lung tissue injury, and inflammatory response in a mouse model of ARDS.


Subject(s)
Epithelium/metabolism , Mesenchymal Stem Cells/cytology , Mitochondria/metabolism , Pulmonary Alveoli/metabolism , Respiratory Distress Syndrome/metabolism , Adenosine Triphosphate/metabolism , Animals , Bone Marrow Cells/cytology , Coculture Techniques , Inflammation , Interleukin-10/metabolism , Interleukin-6/metabolism , Lipopolysaccharides/metabolism , Lung Injury/metabolism , Macrophages/metabolism , Male , Mice , Mice, Inbred C57BL , Oxygen Consumption , RAW 264.7 Cells
4.
J Mol Cell Biol ; 12(12): 916-932, 2020 10 12.
Article in English | MEDLINE | ID: covidwho-968717

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.


Subject(s)
COVID-19/complications , Inflammation/etiology , Lipopolysaccharides/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Animals , Binding Sites , COVID-19/immunology , COVID-19/virology , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/immunology , Disease Models, Animal , Gram-Negative Bacterial Infections/complications , Gram-Negative Bacterial Infections/immunology , Humans , In Vitro Techniques , Lipid A/chemistry , Lipid A/immunology , Lipid A/metabolism , Lipopolysaccharides/chemistry , Lipopolysaccharides/immunology , Mice , Mice, Inbred BALB C , Mice, Transgenic , Models, Immunological , Models, Molecular , Molecular Docking Simulation , Protein Binding , Protein Interaction Domains and Motifs , Respiratory Distress Syndrome/etiology , Risk Factors , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology
5.
Dig Liver Dis ; 52(12): 1383-1389, 2020 12.
Article in English | MEDLINE | ID: covidwho-834313

ABSTRACT

The microbiota-gut-liver-lung axis plays a bidirectional role in the pathophysiology of a number of infectious diseases. During the course of severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and 2 (SARS-CoV-2) infection, this pathway is unbalanced due to intestinal involvement and systemic inflammatory response. Moreover, there is convincing preliminary evidence linking microbiota-gut-liver axis perturbations, proinflammatory status, and endothelial damage in noncommunicable preventable diseases with coronavirus disease 2019 (Covid-19) severity. Intestinal damage due to SARS-CoV-2 infection, systemic inflammation-induced dysfunction, and IL-6-mediated diffuse vascular damage may increase intestinal permeability and precipitate bacterial translocation. The systemic release of damage- and pathogen-associated molecular patterns (e.g. lipopolysaccharides) and consequent immune-activation may in turn auto-fuel vicious cycles of systemic inflammation and tissue damage. Thus, intestinal bacterial translocation may play an additive/synergistic role in the cytokine release syndrome in Covid-19. This review provides evidence on gut-liver axis involvement in Covid-19 as well as insights into the hypothesis that intestinal endotheliitis and permeability changes with bacterial translocation are key pathophysiologic events modulating systemic inflammatory response. Moreover, it presents an overview of readily applicable measures for the modulation of the gut-liver axis and microbiota in clinical practice.


Subject(s)
Bacterial Translocation/immunology , COVID-19/immunology , Cytokine Release Syndrome/immunology , Gastrointestinal Microbiome/immunology , Intestinal Mucosa/metabolism , Lipopolysaccharides/metabolism , Liver/metabolism , Permeability , Alarmins/immunology , Alarmins/metabolism , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Cytokine Release Syndrome/metabolism , Disease Progression , Humans , Immunity/immunology , Inflammation , Interleukin-6/immunology , Lipopolysaccharides/immunology , Liver/immunology , Lung/immunology , Lung/metabolism , Microbiota/immunology , Pathogen-Associated Molecular Pattern Molecules/immunology , Pathogen-Associated Molecular Pattern Molecules/metabolism , SARS-CoV-2/metabolism , Serine Endopeptidases/metabolism
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