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1.
Life Sci ; 305: 120782, 2022 Sep 15.
Article in English | MEDLINE | ID: covidwho-1956258

ABSTRACT

Acute lung injury (ALI) is characterized by diffuse pulmonary infiltrates and causes great mortality. ALI presents with overproduction of proinflammatory cytokines, cell death, destruction of alveoli-endothelial barriers, and neutrophil infiltration in lung tissues. Damage-associated molecular patterns (DAMPs) are molecules released from damaged cells due to infection, trauma, etc. DAMPs activate innate and adaptive immunity, trigger inflammatory responses, and are important in the initiation and development of ALI. We reviewed the literatures on DAMPs in ALI. Alveolar macrophages (AMs), neutrophils, and epithelial cells (AECs) are important in the pathogenesis of ALI. We comprehensively analyzed the interaction between DAMPs and AMs, alveolar neutrophils, and AECs. During the initial stage of ALI, ruptured cell membranes or destroyed mitochondria release DAMPs. DAMPs activate the inflammasome in nearby sentinel immune cells, such as AMs. AMs produce IL-1ß and other cytokines. These mediators upregulate adhesion molecules of the capillary endothelium that facilitate neutrophil recruitment. The recruited neutrophils detect DAMPs using formyl peptide receptors on the membrane, guiding their migration to the injured site. The accumulation of immune cells, cytokines, chemokines, proteases, etc., results in diffuse alveolar damage and pulmonary hyperpermeability with protein-rich fluid retention. Some clinical studies have shown that patients with ALI with higher circulating DAMPs have higher mortality rates. In conclusion, DAMPs are important in the initiation and progression of ALI. The interactions between DAMPs and AMs, neutrophils, and AECs are important in ALI. This review comprehensively addresses the mechanisms of DAMPs and their interactions in ALI.


Subject(s)
Acute Lung Injury , Acute Lung Injury/pathology , Alarmins/metabolism , Animals , Cytokines/metabolism , Humans , Lipopolysaccharides/metabolism , Lung/metabolism , Mice , Mice, Inbred C57BL , Neutrophil Infiltration , Neutrophils/metabolism
2.
Blood ; 139(23): 3402-3417, 2022 06 09.
Article in English | MEDLINE | ID: covidwho-1862095

ABSTRACT

Neutrophils are key players during host defense and sterile inflammation. Neutrophil dysfunction is a characteristic feature of the acquired immunodeficiency during kidney disease. We speculated that the impaired renal clearance of the intrinsic purine metabolite soluble uric acid (sUA) may account for neutrophil dysfunction. Indeed, hyperuricemia (HU, serum UA of 9-12 mg/dL) related or unrelated to kidney dysfunction significantly diminished neutrophil adhesion and extravasation in mice with crystal- and coronavirus-related sterile inflammation using intravital microscopy and an air pouch model. This impaired neutrophil recruitment was partially reversible by depleting UA with rasburicase. We validated these findings in vitro using either neutrophils or serum from patients with kidney dysfunction-related HU with or without UA depletion, which partially normalized the defective migration of neutrophils. Mechanistically, sUA impaired ß2 integrin activity and internalization/recycling by regulating intracellular pH and cytoskeletal dynamics, physiological processes that are known to alter the migratory and phagocytic capability of neutrophils. This effect was fully reversible by blocking intracellular uptake of sUA via urate transporters. In contrast, sUA had no effect on neutrophil extracellular trap formation in neutrophils from healthy subjects or patients with kidney dysfunction. Our results identify an unexpected immunoregulatory role of the intrinsic purine metabolite sUA, which contrasts the well-known immunostimulatory effects of crystalline UA. Specifically targeting UA may help to overcome certain forms of immunodeficiency, for example in kidney dysfunction, but may enhance sterile forms of inflammation.


Subject(s)
CD18 Antigens , Uric Acid , Animals , CD18 Antigens/metabolism , Humans , Immunity, Innate , Inflammation , Mice , Neutrophil Infiltration , Neutrophils , Uric Acid/pharmacology , Uric Acid/urine
3.
Int J Mol Sci ; 22(19)2021 Sep 27.
Article in English | MEDLINE | ID: covidwho-1855649

ABSTRACT

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.


Subject(s)
Cell Degranulation , Cornea/metabolism , Extracellular Traps/metabolism , Eye Diseases/metabolism , Neutrophil Infiltration , Neutrophils/metabolism , Cornea/pathology , Eye Diseases/pathology , Humans , Neutrophils/pathology
4.
Front Immunol ; 13: 866747, 2022.
Article in English | MEDLINE | ID: covidwho-1822363

ABSTRACT

Acute inflammation is a localized and self-limited innate host-defense mechanism against invading pathogens and tissue injury. Neutrophils, the most abundant immune cells in humans, play pivotal roles in host defense by eradicating invading pathogens and debris. Ideally, elimination of the offending insult prompts repair and return to homeostasis. However, the neutrophils` powerful weaponry to combat microbes can also cause tissue damage and neutrophil-driven inflammation is a unifying mechanism for many diseases. For timely resolution of inflammation, in addition to stopping neutrophil recruitment, emigrated neutrophils need to be disarmed and removed from the affected site. Accumulating evidence documents the phenotypic and functional versatility of neutrophils far beyond their antimicrobial functions. Hence, understanding the receptors that integrate opposing cues and checkpoints that determine the fate of neutrophils in inflamed tissues provides insight into the mechanisms that distinguish protective and dysregulated, excessive inflammation and govern resolution. This review aims to provide a brief overview and update with key points from recent advances on neutrophil heterogeneity, functional versatility and signaling, and discusses challenges and emerging therapeutic approaches that target neutrophils to enhance the resolution of inflammation.


Subject(s)
Inflammation , Neutrophils , Homeostasis , Humans , Neutrophil Infiltration , Signal Transduction
5.
Sci Rep ; 12(1): 1856, 2022 02 03.
Article in English | MEDLINE | ID: covidwho-1671631

ABSTRACT

Severe COVID-19 is associated with a systemic hyperinflammatory response leading to acute respiratory distress syndrome (ARDS), multi-organ failure, and death. Galectin-3 is a ß-galactoside binding lectin known to drive neutrophil infiltration and the release of pro-inflammatory cytokines contributing to airway inflammation. Thus, we aimed to investigate the potential of galectin-3 as a biomarker of severe COVID-19 outcomes. We prospectively included 156 patients with RT-PCR confirmed COVID-19. A severe outcome was defined as the requirement of invasive mechanical ventilation (IMV) and/or in-hospital death. A non-severe outcome was defined as discharge without IMV requirement. We used receiver operating characteristic (ROC) and multivariable logistic regression analysis to determine the prognostic ability of serum galectin-3 for a severe outcome. Galectin-3 levels discriminated well between severe and non-severe outcomes and correlated with markers of COVID-19 severity, (CRP, NLR, D-dimer, and neutrophil count). Using a forward-stepwise logistic regression analysis we identified galectin-3 [odds ratio (OR) 3.68 (95% CI 1.47-9.20), p < 0.01] to be an independent predictor of severe outcome. Furthermore, galectin-3 in combination with CRP, albumin and CT pulmonary affection > 50%, had significantly improved ability to predict severe outcomes [AUC 0.85 (95% CI 0.79-0.91, p < 0.0001)]. Based on the evidence presented here, we recommend clinicians measure galectin-3 levels upon admission to facilitate allocation of appropriate resources in a timely manner to COVID-19 patients at highest risk of severe outcome.


Subject(s)
COVID-19/diagnosis , COVID-19/virology , Galectins/blood , SARS-CoV-2 , Adult , Aged , Biomarkers/blood , Blood Proteins , COVID-19/complications , COVID-19/immunology , Cytokines/metabolism , Female , Humans , Inflammation , Inflammation Mediators/metabolism , Male , Middle Aged , Neutrophil Infiltration , Patient Acuity , Predictive Value of Tests , Prognosis , Prospective Studies , Respiratory Distress Syndrome/etiology , Risk
6.
Int Immunopharmacol ; 104: 108516, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1611782

ABSTRACT

Coronavirus disease 2019 (Covid-19) is a worldwide infectious disease caused by severe acute respiratory coronavirus 2 (SARS-CoV-2). In severe SARS-CoV-2 infection, there is severe inflammatory reactions due to neutrophil recruitments and infiltration in the different organs with the formation of neutrophil extracellular traps (NETs), which involved various complications of SARS-CoV-2 infection. Therefore, the objective of the present review was to explore the potential role of NETs in the pathogenesis of SARS-CoV-2 infection and to identify the targeting drugs against NETs in Covid-19 patients. Different enzyme types are involved in the formation of NETs, such as neutrophil elastase (NE), which degrades nuclear protein and release histones, peptidyl arginine deiminase type 4 (PADA4), which releases chromosomal DNA and gasdermin D, which creates pores in the NTs cell membrane that facilitating expulsion of NT contents. Despite of the beneficial effects of NETs in controlling of invading pathogens, sustained formations of NETs during respiratory viral infections are associated with collateral tissue injury. Excessive development of NETs in SARS-CoV-2 infection is linked with the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) due to creation of the NETs-IL-1ß loop. Also, aberrant NTs activation alone or through NETs formation may augment SARS-CoV-2-induced cytokine storm (CS) and macrophage activation syndrome (MAS) in patients with severe Covid-19. Furthermore, NETs formation in SARS-CoV-2 infection is associated with immuno-thrombosis and the development of ALI/ARDS. Therefore, anti-NETs therapy of natural or synthetic sources may mitigate SARS-CoV-2 infection-induced exaggerated immune response, hyperinflammation, immuno-thrombosis, and other complications.


Subject(s)
Acute Lung Injury/immunology , Anti-Inflammatory Agents/pharmacology , COVID-19/immunology , Cytokine Release Syndrome/immunology , Extracellular Traps/immunology , Acute Lung Injury/prevention & control , Acute Lung Injury/virology , Anti-Inflammatory Agents/therapeutic use , COVID-19/complications , COVID-19/drug therapy , COVID-19/virology , Cytokine Release Syndrome/prevention & control , Cytokine Release Syndrome/virology , Extracellular Traps/drug effects , Extracellular Traps/metabolism , Humans , Immunity, Innate/drug effects , Leukocyte Elastase/antagonists & inhibitors , Leukocyte Elastase/metabolism , Neutrophil Infiltration/drug effects , Phosphate-Binding Proteins/antagonists & inhibitors , Phosphate-Binding Proteins/metabolism , Pore Forming Cytotoxic Proteins/antagonists & inhibitors , Pore Forming Cytotoxic Proteins/metabolism , Protein-Arginine Deiminase Type 4/antagonists & inhibitors , Protein-Arginine Deiminase Type 4/metabolism , SARS-CoV-2/immunology
7.
J Autoimmun ; 127: 102783, 2022 02.
Article in English | MEDLINE | ID: covidwho-1587360

ABSTRACT

Vaccinations may induce cutaneous adverse events, due to nonspecific inflammation or immuno-mediated reactions. Several types of vasculitis have been observed. We report on a 71-year-old woman who developed cutaneous small-vessel vasculitis after the second dose of Vaxzevria COVID-19 vaccination, showing leukocytoclastic vasculitis on histopathological examination of a skin biopsy. Cutaneous small-vessel vasculitis is a rare condition which can be idiopathic or secondary to underlying infections, connective tissue disorders, malignancy, and medications. The pathogenesis involves immune complex deposition in small blood vessels, leading to activation of the complement system and recruitment of leukocytes. Exacerbation of small-vessel vasculitis has been reported following the administration of various vaccines, particularly influenza vaccine. It is expected that SARS-CoV-2 vaccine results in the activation of B- and T-cells and antibody formation. We hypothesize that leukocytoclastic vasculitis caused by immune complex deposition within cutaneous small vessels could be a rare side effect of Vaxzevria COVID-19 vaccination.


Subject(s)
COVID-19 Vaccines/adverse effects , Vasculitis, Leukocytoclastic, Cutaneous/etiology , Aged , Female , Humans , Neutrophil Infiltration , Prednisone/therapeutic use , Vasculitis, Leukocytoclastic, Cutaneous/blood , Vasculitis, Leukocytoclastic, Cutaneous/drug therapy , Vasculitis, Leukocytoclastic, Cutaneous/pathology
8.
Int J Mol Sci ; 22(23)2021 Nov 29.
Article in English | MEDLINE | ID: covidwho-1561718

ABSTRACT

S100A9, a pro-inflammatory alarmin, is up-regulated in inflamed tissues. However, the role of S100A9 in regulating neutrophil activation, inflammation and lung damage in sepsis is not known. Herein, we hypothesized that blocking S100A9 function may attenuate neutrophil recruitment in septic lung injury. Male C57BL/6 mice were pretreated with the S100A9 inhibitor ABR-238901 (10 mg/kg), prior to cercal ligation and puncture (CLP). Bronchoalveolar lavage fluid (BALF) and lung tissue were harvested for analysis of neutrophil infiltration as well as edema and CXC chemokine production. Blood was collected for analysis of membrane-activated complex-1 (Mac-1) expression on neutrophils as well as CXC chemokines and IL-6 in plasma. Induction of CLP markedly increased plasma levels of S100A9. ABR-238901 decreased CLP-induced neutrophil infiltration and edema formation in the lung. In addition, inhibition of S100A9 decreased the CLP-induced up-regulation of Mac-1 on neutrophils. Administration of ABR-238901 also inhibited the CLP-induced increase of CXCL-1, CXCL-2 and IL-6 in plasma and lungs. Our results suggest that S100A9 promotes neutrophil activation and pulmonary accumulation in sepsis. Targeting S100A9 function decreased formation of CXC chemokines in circulation and lungs and attenuated sepsis-induced lung damage. These novel findings suggest that S100A9 plays an important pro-inflammatory role in sepsis and could be a useful target to protect against the excessive inflammation and lung damage associated with the disease.


Subject(s)
Acute Lung Injury/prevention & control , Calgranulin B/metabolism , Neutrophil Infiltration/drug effects , Sepsis/complications , Sulfonamides/therapeutic use , Acute Lung Injury/etiology , Acute Lung Injury/metabolism , Animals , Chemokines, CXC/metabolism , Drug Evaluation, Preclinical , Interleukin-6/metabolism , Lung/metabolism , Male , Mice, Inbred C57BL , Sepsis/immunology , Sepsis/metabolism , Sulfonamides/pharmacology
9.
Int J Mol Sci ; 22(23)2021 Nov 24.
Article in English | MEDLINE | ID: covidwho-1560167

ABSTRACT

Streptococcus pneumoniae is an important causative organism of respiratory tract infections. Although periodontal bacteria have been shown to influence respiratory infections such as aspiration pneumonia, the synergistic effect of S. pneumoniae and Porphyromonas gingivalis, a periodontopathic bacterium, on pneumococcal infections is unclear. To investigate whether P. gingivalis accelerates pneumococcal infections, we tested the effects of inoculating P. gingivalis culture supernatant (PgSup) into S. pneumoniae-infected mice. Mice were intratracheally injected with S. pneumoniae and PgSup to induce pneumonia, and lung histopathological sections and the absolute number and frequency of neutrophils and macrophages in the lung were analyzed. Proinflammatory cytokine/chemokine expression was examined by qPCR and ELISA. Inflammatory cell infiltration was observed in S. pneumoniae-infected mice and S. pnemoniae and PgSup mixed-infected mice, and mixed-infected mice showed more pronounced inflammation in lung. The ratios of monocytes/macrophages and neutrophils were not significantly different between the lungs of S. pneumoniae-infected mice and those of mixed-infected mice. PgSup synergistically increased TNF-α expression/production and IL-17 production compared with S. pneumoniae infection alone. We demonstrated that PgSup enhanced inflammation in pneumonia caused by S. pneumoniae, suggesting that virulence factors produced by P. gingivalis are involved in the exacerbation of respiratory tract infections such as aspiration pneumonia.


Subject(s)
Bacteroidaceae Infections/complications , Inflammation/pathology , Lung/pathology , Neutrophil Infiltration/immunology , Pneumonia, Pneumococcal/pathology , Porphyromonas gingivalis/physiology , Streptococcus pneumoniae/physiology , Animals , Bacteroidaceae Infections/microbiology , Chemokines/metabolism , Cytokines/metabolism , Inflammation/etiology , Lung/immunology , Lung/metabolism , Lung/microbiology , Mice , Mice, Inbred C57BL , Pneumonia, Pneumococcal/epidemiology , Pneumonia, Pneumococcal/metabolism , Pneumonia, Pneumococcal/microbiology
10.
Blood ; 139(14): 2130-2144, 2022 04 07.
Article in English | MEDLINE | ID: covidwho-1457448

ABSTRACT

Modulation of neutrophil recruitment and function is crucial for targeting inflammatory cells to sites of infection to combat invading pathogens while, at the same time, limiting host tissue injury or autoimmunity. The underlying mechanisms regulating recruitment of neutrophils, 1 of the most abundant inflammatory cells, have gained increasing interest over the years. The previously described classical recruitment cascade of leukocytes has been extended to include capturing, rolling, adhesion, crawling, and transmigration, as well as a reverse-transmigration step that is crucial for balancing immune defense and control of remote organ endothelial leakage. Current developments in the field emphasize the importance of cellular interplay, tissue environmental cues, circadian rhythmicity, detection of neutrophil phenotypes, differential chemokine sensing, and contribution of distinct signaling components to receptor activation and integrin conformations. The use of therapeutics modulating neutrophil activation responses, as well as mutations causing dysfunctional neutrophil receptors and impaired signaling cascades, have been defined in translational animal models. Human correlates of such mutations result in increased susceptibility to infections or organ damage. This review focuses on current advances in the understanding of the regulation of neutrophil recruitment and functionality and translational implications of current discoveries in the field with a focus on acute inflammation and sepsis.


Subject(s)
Neutrophil Activation , Neutrophils , Animals , Humans , Inflammation , Integrins , Neutrophil Infiltration
11.
Molecules ; 26(17)2021 Sep 02.
Article in English | MEDLINE | ID: covidwho-1390702

ABSTRACT

Human neutrophil elastase (HNE) is a uniquely destructive serine protease with the ability to unleash a wave of proteolytic activity by destroying the inhibitors of other proteases. Although this phenomenon forms an important part of the innate immune response to invading pathogens, it is responsible for the collateral host tissue damage observed in chronic conditions such as chronic obstructive pulmonary disease (COPD), and in more acute disorders such as the lung injuries associated with COVID-19 infection. Previously, a combinatorially selected activity-based probe revealed an unexpected substrate preference for oxidised methionine, which suggests a link to oxidative pathogen clearance by neutrophils. Here we use oxidised model substrates and inhibitors to confirm this observation and to show that neutrophil elastase is specifically selective for the di-oxygenated methionine sulfone rather than the mono-oxygenated methionine sulfoxide. We also posit a critical role for ordered solvent in the mechanism of HNE discrimination between the two oxidised forms methionine residue. Preference for the sulfone form of oxidised methionine is especially significant. While both host and pathogens have the ability to reduce methionine sulfoxide back to methionine, a biological pathway to reduce methionine sulfone is not known. Taken together, these data suggest that the oxidative activity of neutrophils may create rapidly cleaved elastase "super substrates" that directly damage tissue, while initiating a cycle of neutrophil oxidation that increases elastase tissue damage and further neutrophil recruitment.


Subject(s)
Immunity, Innate , Leukocyte Elastase/metabolism , Methionine/analogs & derivatives , Neutrophils/immunology , Biocatalysis , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Catalytic Domain/genetics , Enzyme Assays , Host-Pathogen Interactions/immunology , Humans , Leukocyte Elastase/antagonists & inhibitors , Leukocyte Elastase/genetics , Lung/immunology , Lung/pathology , Lung/virology , Methionine/metabolism , Molecular Dynamics Simulation , Neutrophil Infiltration , Neutrophils/enzymology , Oxidation-Reduction/drug effects , Proteolysis/drug effects , Pulmonary Disease, Chronic Obstructive/immunology , Pulmonary Disease, Chronic Obstructive/pathology , SARS-CoV-2/immunology , Substrate Specificity/immunology
12.
Lancet Infect Dis ; 20(10): 1135-1140, 2020 10.
Article in English | MEDLINE | ID: covidwho-1377877

ABSTRACT

BACKGROUND: COVID-19 is characterised by respiratory symptoms, which deteriorate into respiratory failure in a substantial proportion of cases, requiring intensive care in up to a third of patients admitted to hospital. Analysis of the pathological features in the lung tissues of patients who have died with COVID-19 could help us to understand the disease pathogenesis and clinical outcomes. METHODS: We systematically analysed lung tissue samples from 38 patients who died from COVID-19 in two hospitals in northern Italy between Feb 29 and March 24, 2020. The most representative areas identified at macroscopic examination were selected, and tissue blocks (median seven, range five to nine) were taken from each lung and fixed in 10% buffered formalin for at least 48 h. Tissues were assessed with use of haematoxylin and eosin staining, immunohistochemical staining for inflammatory infiltrate and cellular components (including staining with antibodies against CD68, CD3, CD45, CD61, TTF1, p40, and Ki-67), and electron microscopy to identify virion localisation. FINDINGS: All cases showed features of the exudative and proliferative phases of diffuse alveolar damage, which included capillary congestion (in all cases), necrosis of pneumocytes (in all cases), hyaline membranes (in 33 cases), interstitial and intra-alveolar oedema (in 37 cases), type 2 pneumocyte hyperplasia (in all cases), squamous metaplasia with atypia (in 21 cases), and platelet-fibrin thrombi (in 33 cases). The inflammatory infiltrate, observed in all cases, was largely composed of macrophages in the alveolar lumina (in 24 cases) and lymphocytes in the interstitium (in 31 cases). Electron microscopy revealed that viral particles were predominantly located in the pneumocytes. INTERPRETATION: The predominant pattern of lung lesions in patients with COVID-19 patients is diffuse alveolar damage, as described in patients infected with severe acute respiratory syndrome and Middle East respiratory syndrome coronaviruses. Hyaline membrane formation and pneumocyte atypical hyperplasia are frequent. Importantly, the presence of platelet-fibrin thrombi in small arterial vessels is consistent with coagulopathy, which appears to be common in patients with COVID-19 and should be one of the main targets of therapy. FUNDING: None.


Subject(s)
Coronavirus Infections/pathology , Lung/pathology , Pneumonia, Viral/pathology , Adult , Aged , Aged, 80 and over , Autopsy , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Female , Humans , Hyaline Membrane Disease , Inflammation , Italy/epidemiology , Lung/blood supply , Lung/ultrastructure , Lung/virology , Male , Middle Aged , Neutrophil Infiltration , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Pulmonary Alveoli/blood supply , Pulmonary Alveoli/pathology , Pulmonary Alveoli/ultrastructure , Pulmonary Alveoli/virology , Pulmonary Artery/pathology , SARS-CoV-2 , Thrombosis
13.
J Neuroimmune Pharmacol ; 16(1): 59-70, 2021 03.
Article in English | MEDLINE | ID: covidwho-1018438

ABSTRACT

COVID-19 is an infectious respiratory illness caused by the virus strain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and until now, there is no effective therapy against COVID-19. Since SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) for entering into host cells, to target COVID-19 from therapeutic angle, we engineered a hexapeptide corresponding to the ACE2-interacting domain of SARS-CoV-2 (AIDS) that inhibits the association between receptor-binding domain-containing spike S1 and ACE-2. Accordingly, wild type (wt), but not mutated (m), AIDS peptide inhibited SARS-CoV-2 spike S1-induced activation of NF-κB and expression of IL-6 in human lungs cells. Interestingly, intranasal intoxication of C57/BL6 mice with recombinant SARS-CoV-2 spike S1 led to fever, increase in IL-6 in lungs, infiltration of neutrophils into the lungs, arrhythmias, and impairment in locomotor activities, mimicking some of the important symptoms of COVID-19. However, intranasal treatment with wtAIDS, but not mAIDS, peptide reduced fever, protected lungs, improved heart function, and enhanced locomotor activities in SARS-CoV-2 spike S1-intoxicated mice. Therefore, selective targeting of ACE2-to-SARS-CoV-2 interaction by wtAIDS may be beneficial for COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/therapeutic use , COVID-19/complications , COVID-19/drug therapy , Fever/drug therapy , Fever/etiology , Heart Diseases/etiology , Heart Diseases/prevention & control , Inflammation/drug therapy , Inflammation/etiology , Lung Diseases/etiology , Lung Diseases/prevention & control , Peptide Fragments/therapeutic use , Administration, Intranasal , Animals , Arrhythmias, Cardiac/etiology , Arrhythmias, Cardiac/prevention & control , COVID-19/pathology , Female , Heart Diseases/pathology , Interleukin-6/metabolism , Lung Diseases/pathology , Male , Mice , Mice, Inbred C57BL , Motor Activity/drug effects , Neutrophil Infiltration/drug effects , Spike Glycoprotein, Coronavirus/toxicity
14.
PLoS One ; 15(12): e0242318, 2020.
Article in English | MEDLINE | ID: covidwho-955356

ABSTRACT

The acute respiratory distress syndrome (ARDS) is characterized by intense dysregulated inflammation leading to acute lung injury (ALI) and respiratory failure. There are no effective pharmacologic therapies for ARDS. Colchicine is a low-cost, widely available drug, effective in the treatment of inflammatory conditions. We studied the effects of colchicine pre-treatment on oleic acid-induced ARDS in rats. Rats were treated with colchicine (1 mg/kg) or placebo for three days prior to intravenous oleic acid-induced ALI (150 mg/kg). Four hours later they were studied and compared to a sham group. Colchicine reduced the area of histological lung injury by 61%, reduced lung edema, and markedly improved oxygenation by increasing PaO2/FiO2 from 66 ± 13 mmHg (mean ± SEM) to 246 ± 45 mmHg compared to 380 ± 18 mmHg in sham animals. Colchicine also reduced PaCO2 and respiratory acidosis. Lung neutrophil recruitment, assessed by myeloperoxidase immunostaining, was greatly increased after injury from 1.16 ± 0.19% to 8.86 ± 0.66% and significantly reduced by colchicine to 5.95 ± 1.13%. Increased lung NETosis was also reduced by therapy. Circulating leukocytosis after ALI was not reduced by colchicine therapy, but neutrophils reactivity and CD4 and CD8 cell surface expression on lymphocyte populations were restored. Colchicine reduces ALI and respiratory failure in experimental ARDS in relation with reduced lung neutrophil recruitment and reduced circulating leukocyte activation. This study supports the clinical development of colchicine for the prevention of ARDS in conditions causing ALI.


Subject(s)
Acute Lung Injury/drug therapy , Colchicine/pharmacology , Lung/drug effects , Respiratory Distress Syndrome/drug therapy , Acute Lung Injury/blood , Acute Lung Injury/chemically induced , Acute Lung Injury/pathology , Animals , Disease Models, Animal , Humans , Lung/pathology , Neutrophil Infiltration/drug effects , Neutrophils/drug effects , Oleic Acid/toxicity , Rats , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/chemically induced , Respiratory Distress Syndrome/pathology
15.
Cell ; 184(2): 460-475.e21, 2021 01 21.
Article in English | MEDLINE | ID: covidwho-917237

ABSTRACT

SARS-CoV-2-induced hypercytokinemia and inflammation are critically associated with COVID-19 severity. Baricitinib, a clinically approved JAK1/JAK2 inhibitor, is currently being investigated in COVID-19 clinical trials. Here, we investigated the immunologic and virologic efficacy of baricitinib in a rhesus macaque model of SARS-CoV-2 infection. Viral shedding measured from nasal and throat swabs, bronchoalveolar lavages, and tissues was not reduced with baricitinib. Type I interferon (IFN) antiviral responses and SARS-CoV-2-specific T cell responses remained similar between the two groups. Animals treated with baricitinib showed reduced inflammation, decreased lung infiltration of inflammatory cells, reduced NETosis activity, and more limited lung pathology. Importantly, baricitinib-treated animals had a rapid and remarkably potent suppression of lung macrophage production of cytokines and chemokines responsible for inflammation and neutrophil recruitment. These data support a beneficial role for, and elucidate the immunological mechanisms underlying, the use of baricitinib as a frontline treatment for inflammation induced by SARS-CoV-2 infection.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Azetidines/administration & dosage , COVID-19/drug therapy , COVID-19/immunology , Macaca mulatta , Neutrophil Infiltration/drug effects , Purines/administration & dosage , Pyrazoles/administration & dosage , Sulfonamides/administration & dosage , Animals , COVID-19/physiopathology , Cell Death/drug effects , Cell Degranulation/drug effects , Disease Models, Animal , Inflammation/drug therapy , Inflammation/genetics , Inflammation/immunology , Janus Kinases/antagonists & inhibitors , Lung/drug effects , Lung/immunology , Lung/pathology , Lymphocyte Activation/drug effects , Macrophages, Alveolar/immunology , SARS-CoV-2/physiology , Severity of Illness Index , T-Lymphocytes/immunology , Virus Replication/drug effects
16.
Front Immunol ; 11: 2063, 2020.
Article in English | MEDLINE | ID: covidwho-868947

ABSTRACT

Background: Cases of excessive neutrophil counts in the blood in severe coronavirus disease (COVID-19) patients have drawn significant attention. Neutrophil infiltration was also noted on the pathological findings from autopsies. It is urgent to clarify the pathogenesis of neutrophils leading to severe pneumonia in COVID-19. Methods: A retrospective analysis was performed on 55 COVID-19 patients classified as mild (n = 22), moderate (n = 25), and severe (n = 8) according to the Guidelines released by the National Health Commission of China. Trends relating leukocyte counts and lungs examined by chest CT scan were quantified by Bayesian inference. Transcriptional signatures of host immune cells of four COVID19 patients were analyzed by RNA sequencing of lung specimens and BALF. Results: Neutrophilia occurred in 6 of 8 severe patients at 7-19 days after symptom onset, coinciding with lesion progression. Increasing neutrophil counts paralleled lesion CT values (slope: 0.8 and 0.3-1.2), reflecting neutrophilia-induced lung injury in severe patients. Transcriptome analysis revealed that neutrophil activation was correlated with 17 neutrophil extracellular trap (NET)-associated genes in COVID-19 patients, which was related to innate immunity and interacted with T/NK/B cells, as supported by a protein-protein interaction network analysis. Conclusion: Excessive neutrophils and associated NETs could explain the pathogenesis of lung injury in COVID-19 pneumonia.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/immunology , Extracellular Traps/genetics , Neutrophil Activation/genetics , Neutrophils/immunology , Pneumonia, Viral/immunology , Adult , Aged , Bayes Theorem , COVID-19 , Coronavirus Infections/virology , Female , Humans , Leukocyte Count , Lung Injury/immunology , Lung Injury/pathology , Male , Middle Aged , Neutrophil Infiltration/immunology , Pandemics , Pneumonia, Viral/virology , Protein Interaction Maps/immunology , RNA, Viral/genetics , Retrospective Studies , SARS-CoV-2 , Transcriptome
17.
J Virol ; 94(20)2020 09 29.
Article in English | MEDLINE | ID: covidwho-840609

ABSTRACT

Alpha/beta interferon (IFN-α/ß) signaling through the IFN-α/ß receptor (IFNAR) is essential to limit virus dissemination throughout the central nervous system (CNS) following many neurotropic virus infections. However, the distinct expression patterns of factors associated with the IFN-α/ß pathway in different CNS resident cell populations implicate complex cooperative pathways in IFN-α/ß induction and responsiveness. Here we show that mice devoid of IFNAR1 signaling in calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) expressing neurons (CaMKIIcre:IFNARfl/fl mice) infected with a mildly pathogenic neurotropic coronavirus (mouse hepatitis virus A59 strain [MHV-A59]) developed severe encephalomyelitis with hind-limb paralysis and succumbed within 7 days. Increased virus spread in CaMKIIcre:IFNARfl/fl mice compared to IFNARfl/fl mice affected neurons not only in the forebrain but also in the mid-hind brain and spinal cords but excluded the cerebellum. Infection was also increased in glia. The lack of viral control in CaMKIIcre:IFNARfl/fl relative to control mice coincided with sustained Cxcl1 and Ccl2 mRNAs but a decrease in mRNA levels of IFNα/ß pathway genes as well as Il6, Tnf, and Il1ß between days 4 and 6 postinfection (p.i.). T cell accumulation and IFN-γ production, an essential component of virus control, were not altered. However, IFN-γ responsiveness was impaired in microglia/macrophages irrespective of similar pSTAT1 nuclear translocation as in infected controls. The results reveal how perturbation of IFN-α/ß signaling in neurons can worsen disease course and disrupt complex interactions between the IFN-α/ß and IFN-γ pathways in achieving optimal antiviral responses.IMPORTANCE IFN-α/ß induction limits CNS viral spread by establishing an antiviral state, but also promotes blood brain barrier integrity, adaptive immunity, and activation of microglia/macrophages. However, the extent to which glial or neuronal signaling contributes to these diverse IFN-α/ß functions is poorly understood. Using a neurotropic mouse hepatitis virus encephalomyelitis model, this study demonstrated an essential role of IFN-α/ß receptor 1 (IFNAR1) specifically in neurons to control virus spread, regulate IFN-γ signaling, and prevent acute mortality. The results support the notion that effective neuronal IFNAR1 signaling compensates for their low basal expression of genes in the IFN-α/ß pathway compared to glia. The data further highlight the importance of tightly regulated communication between the IFN-α/ß and IFN-γ signaling pathways to optimize antiviral IFN-γ activity.


Subject(s)
Central Nervous System/virology , Interferon Type I/metabolism , Interferon-gamma/metabolism , Macrophages/metabolism , Microglia/metabolism , Neurons/metabolism , Signal Transduction , Animals , Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Central Nervous System/immunology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Encephalomyelitis/immunology , Encephalomyelitis/virology , Macrophages/virology , Mice , Mice, Mutant Strains , Microglia/virology , Murine hepatitis virus/physiology , Neurons/virology , Neutrophil Infiltration , Receptor, Interferon alpha-beta/deficiency , Receptor, Interferon alpha-beta/genetics , Receptor, Interferon alpha-beta/metabolism , Virus Replication
18.
Front Immunol ; 11: 2145, 2020.
Article in English | MEDLINE | ID: covidwho-776206

ABSTRACT

SARS-CoV-2 infection has recently been declared a pandemic. Some patients showing severe symptoms exhibit drastic inflammation and airway damage. In this study, we re-analyzed published scRNA-seq data of COVID-19 patient bronchoalveolar lavage fluid to further classify and compare immunological features according to the patient's disease severity. Patients with severe symptoms showed DNA damage and apoptotic features of epithelial cells. Our results suggested that epithelial damage was associated with neutrophil infiltration. Myeloid cells of severe patients showed higher expression of proinflammatory cytokines and chemokines such as CXCL8. As a result, neutrophils were abundant in lungs of patients from the severe group. Furthermore, recruited neutrophils highly expressed genes related to neutrophil extracellular traps. Neutrophil-mediated inflammation was regulated by glucocorticoid receptor expression and activity. Based on these results, we suggest that severe COVID-19 symptoms may be determined by differential expression of glucocorticoid receptors and neutrophils.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Interleukin-8/genetics , Neutrophils/immunology , Pneumonia, Viral/immunology , Receptors, Glucocorticoid/genetics , Severity of Illness Index , Transcriptome , Adult , Aged , Bronchoalveolar Lavage Fluid/immunology , COVID-19 , Coronavirus Infections/virology , Epithelial Cells/pathology , Extracellular Traps/immunology , Female , Gene Expression Profiling/methods , Humans , Inflammation/immunology , Interleukin-8/metabolism , Male , Middle Aged , Myeloid Cells/immunology , Neutrophil Infiltration/immunology , Pandemics , Pneumonia, Viral/virology , RNA-Seq , Receptors, Glucocorticoid/metabolism , SARS-CoV-2 , Single-Cell Analysis/methods
19.
Arthritis Rheumatol ; 73(1): 23-35, 2021 01.
Article in English | MEDLINE | ID: covidwho-757767

ABSTRACT

The clinical progression of the severe acute respiratory syndrome coronavirus 2 infection, coronavirus 2019 (COVID-19), to critical illness is associated with an exaggerated immune response, leading to magnified inflammation termed the "cytokine storm." This response is thought to contribute to the pathogenicity of severe COVID-19. There is an initial weak interferon response and macrophage activation that results in delayed neutrophil recruitment leading to impeded viral clearance. This causes prolonged immune stimulation and the release of proinflammatory cytokines. Elevated inflammatory markers in COVID-19 (e.g., d-dimer, C-reactive protein, lactate dehydrogenase, ferritin, and interleukin-6) are reminiscent of the cytokine storm seen in severe hyperinflammatory macrophage disorders. The dysfunctional immune response in COVID-19 also includes lymphopenia, reduced T cells, reduced natural killer cell maturation, and unmitigated plasmablast proliferation causing aberrant IgG levels. The progression to severe disease is accompanied by endotheliopathy, immunothrombosis, and hypercoagulability. Thus, both parts of the immune system-innate and adaptive-play a significant role in the cytokine storm, multiorgan dysfunction, and coagulopathy. This review highlights the importance of understanding the immunologic mechanisms of COVID-19 as they inform the clinical presentation and advise potential therapeutic targets.


Subject(s)
Adaptive Immunity/immunology , COVID-19/immunology , Cytokine Release Syndrome/immunology , Immunity, Innate/immunology , Respiratory Distress Syndrome/immunology , Antibody Formation , Antiviral Agents/therapeutic use , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/blood , COVID-19/drug therapy , COVID-19/physiopathology , Complement Inactivating Agents/therapeutic use , Cytokines/antagonists & inhibitors , Cytokines/immunology , Endothelium, Vascular/immunology , Endothelium, Vascular/physiopathology , Humans , Immunity, Humoral/immunology , Immunoglobulin G/immunology , Immunologic Factors/therapeutic use , Immunologic Memory , Immunosuppressive Agents/therapeutic use , Interferons/immunology , Killer Cells, Natural/immunology , Lymphopenia/immunology , Macrophage Activation/immunology , Neutrophil Infiltration/immunology , SARS-CoV-2 , Systemic Inflammatory Response Syndrome/immunology , Thrombophilia/blood , Thrombophilia/immunology , Thrombosis/blood , Thrombosis/immunology
20.
Blood ; 136(10): 1169-1179, 2020 09 03.
Article in English | MEDLINE | ID: covidwho-748867

ABSTRACT

COVID-19 affects millions of patients worldwide, with clinical presentation ranging from isolated thrombosis to acute respiratory distress syndrome (ARDS) requiring ventilator support. Neutrophil extracellular traps (NETs) originate from decondensed chromatin released to immobilize pathogens, and they can trigger immunothrombosis. We studied the connection between NETs and COVID-19 severity and progression. We conducted a prospective cohort study of COVID-19 patients (n = 33) and age- and sex-matched controls (n = 17). We measured plasma myeloperoxidase (MPO)-DNA complexes (NETs), platelet factor 4, RANTES, and selected cytokines. Three COVID-19 lung autopsies were examined for NETs and platelet involvement. We assessed NET formation ex vivo in COVID-19 neutrophils and in healthy neutrophils incubated with COVID-19 plasma. We also tested the ability of neonatal NET-inhibitory factor (nNIF) to block NET formation induced by COVID-19 plasma. Plasma MPO-DNA complexes increased in COVID-19, with intubation (P < .0001) and death (P < .0005) as outcome. Illness severity correlated directly with plasma MPO-DNA complexes (P = .0360), whereas Pao2/fraction of inspired oxygen correlated inversely (P = .0340). Soluble and cellular factors triggering NETs were significantly increased in COVID-19, and pulmonary autopsies confirmed NET-containing microthrombi with neutrophil-platelet infiltration. Finally, COVID-19 neutrophils ex vivo displayed excessive NETs at baseline, and COVID-19 plasma triggered NET formation, which was blocked by nNIF. Thus, NETs triggering immunothrombosis may, in part, explain the prothrombotic clinical presentations in COVID-19, and NETs may represent targets for therapeutic intervention.


Subject(s)
Coronavirus Infections/complications , Extracellular Traps/immunology , Neutrophils/immunology , Pneumonia, Viral/complications , Thrombosis/complications , Adult , Aged , Betacoronavirus/immunology , Blood Platelets/immunology , Blood Platelets/pathology , Blood Proteins/immunology , COVID-19 , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Female , Humans , Male , Middle Aged , Neutrophil Infiltration , Neutrophils/pathology , Pandemics , Peroxidase/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Prospective Studies , SARS-CoV-2 , Thrombosis/immunology , Thrombosis/pathology
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