scholarly journals Neutrophil Metabolic Rewiring in Severe and Mild COVID-19

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3129-3129
Author(s):  
Yafeng Li ◽  
Jessica S Hook ◽  
Qing Ding ◽  
Stephen Chung ◽  
Jessica Moreland ◽  
...  
Keyword(s):  
Immune Cell ◽  
Conflicts Of Interest ◽  
Central Carbon Metabolism ◽  
Nucleotide Metabolism ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Healthy Controls ◽  
Public Health Importance ◽  
Mild Disease ◽  
Plasma Metabolome

Abstract SARS-CoV-2 infection can cause severe respiratory disease resulting in hospitalization and death in some people, but in others it causes a mild disease or is asymptomatic. The causes of severe COVID-19 are of profound public health importance. Severe COVID-19 is marked by an exacerbated innate immune response leading to hyperinflammation which damages host tissues. Broad inhibition of hyperinflammation by dexamethasone is a mainstay of severe COVID-19 treatment. However, more targeted therapeutic approaches to dampen hyperinflammation are lacking. Patients typically exhibit increased neutrophil numbers in the blood and lung, and increased formation of neutrophil extracellular traps. Previous work profiled the metabolome of plasma in severe COVID-19 patients and found several metabolic aberrations as compared to mild COVID-19 patients or healthy controls. However, the metabolome of immune cell populations in COVID-19 has not been characterized to our knowledge. In addition, it is not known if metabolic changes observed in severe COVID-19 mechanistically contribute to hyperinflammation and host tissue damage or if they are simply markers of pathology. To understand how metabolism can regulate the innate immune system in COVID-19 and to explore possible therapeutic targets, we carried out a comprehensive metabolomic study of neutrophils purified from healthy controls, mild/moderate COVID-19 patients, and severe COVID-19 patients. Severe COVID-19 patients were defined as having Acute Respiratory Distress and being treated in the intensive care unit. Plasma from the same patients and healthy controls was also collected and metabolomics was performed to study how COVID-19 impacts the neutrophil and plasma metabolome in tandem. Several metabolic pathways were significantly different between mild COVID-19 patients, severe COVID-19 patients, and healthy controls, consistent with rewired neutrophil and plasma metabolome in severe COVID-19. Differentially abundant metabolites belonged to central carbon metabolism, nucleotide metabolism, amino acid metabolism and other pathways. Variation in the PMN metabolome was largely independent from variation in the plasma metabolome. This suggests that processes internal to neutrophils drive changes in neutrophil metabolism. Metabolomics in 3 mouse models of hyperinflammation showed common or distinct metabolic features that change in inflammation compared to metabolomics of severe COVID-19 patients. Therefore changes in some metabolites comprise a general hyperinflammatory metabolic signature while others are more specific to severe COVID-19. Isotope tracing experiments were carried out to understand how nutrients were utilized in neutrophils in context of inflammation. We will describe mechanistic work testing whether metabolic features we observe in severe COVID-19 patients regulate the inflammatory response of human neutrophils. Disclosures No relevant conflicts of interest to declare.

Innate Immune Cell Expression of Pattern Recognition Receptors From β-Thalassemia Patients During Intensive Combination Chelation Therapy

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1025-1025 ◽  
Author(s):  
Patrick B Walter ◽  
Paul Harmatz ◽  
Annie Higa ◽  
Vivian Ng ◽  
Marcela G Weyhmiller ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Iron Overload ◽  
Immune Function ◽  
Research Funding ◽  
Immune Cell ◽  
Innate Immune ◽  
Expression Level ◽  
Healthy Controls ◽  
Blood Samples ◽  
Cell Expression

Abstract Abstract 1025 Introduction: Thalassemia major patients endure chronic RBC transfusions, high levels of tissue iron, iron chelation and organ injury. Patients with thalassemia also have reduced immune function and are at risk for infection. Infection is in fact the second most common cause of death in thalassemia. The innate immune system provides the first line of defense against infection and it specificity depends on pattern recognition receptors (PRRs) specific to microbial pathogens. One class of PRR called the toll-like receptors (TLRs) interact with CD14 on innate immune cells transducing the signal for bacterial Lipopolysaccharide (LPS), resulting in cytokine production. The role iron plays in thalassemia in determining expression level of PRRs is unknown. Thus, the goal in these studies is to investigate the relationship of iron overload and its chelation to innate immune cell expression of PRRs in thalassemia. Patients and Methods: Eighteen transfusion dependent thalassemia patients (11 – 29 yrs old) participating in the combination trial of deferasirox and deferoxamine (Novartis sponsored CICL670AUS24T) were enrolled in a substudy investigating innate immunology (Novartis sponsored CICL670AUS42T). Fasting blood samples were obtained i) at baseline after a 72 hr. washout of chelator, and ii) at 6 and 12 months on study. Fourteen healthy controls (10 – 35 yrs old) were also enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples and then from these cells monocytes and granulocytes were purified using antibody-linked magnetic microbeads (Miltenyi Biotec Inc). Highly enriched populations of CD14+ monocytes and CD15+ granulocytes were verified by flow cytometry. The expression level of CD14 and CD15 in PBMCs and TLR4 in purified cells were determined and reported as the median fluorescent intensity (MFI). Liver iron concentration (LIC) was determined by biomagnetic susceptibility (“SQUID”, Ferritometer®) in patients with thalassemia; healthy controls were shown to have normal ferritin. Results: In PBMCs from thalassemia patients at baseline, the expression of monocyte CD14 and TLR4 were significantly increased 22% and 6.5% respectively compared to healthy controls (p < 0.05). Granulocytes from patients with thalassemia at baseline were also found to have a 50% higher expression of TLR4 compared to controls. Markers of iron burden, such as LIC and ferritin also significantly correlated with the expression of monocyte TLR4. In longitudinal analysis markers of iron burden, the expression of TLR4 on monocytes and granulocytes all significantly decreased in the follow-up period in thalassemia patients receiving intensive combination chelator therapy (p<0.05). Conclusions: These studies support the hypothesis that iron burden influences the innate immune response in thalassemia as demonstrated by the increased monocyte expression of both CD14 and TLR4 at baseline, both of which likely contribute to the commonly observed susceptibility to infection. After intensive chelation, the levels of CD14 and TLR4 decreased, indicating that decreased iron overload with chelation may improve innate immune responsiveness. These changes in CD14 and TLR4 may be able to restore proper innate immune function in thalassemia patients. Disclosures: Walter: Novartis: Research Funding. Harmatz:Novartis: Research Funding; FerroKin BioSciences: Research Funding. Porter:Novartis: Consultancy, Research Funding. Vichinsky:ARUP Research Lab: Research Funding; ApoPharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.

scholarly journals Cysteinyl Leukotriene Receptor-1 Antagonists as Modulators of Innate Immune Cell Function

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
A. J. Theron ◽  
H. C. Steel ◽  
G. R. Tintinger ◽  
C. M. Gravett ◽  
R. Anderson ◽  
...  
Keyword(s):  
Cell Function ◽  
Immune Cell ◽  
Cell Types ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Cysteinyl Leukotriene ◽  
Anti Inflammatory ◽  
Cysteinyl Leukotriene Receptor ◽  
Underlying Mechanisms

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8+cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophilsin vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

scholarly journals Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms

2021 ◽  
Vol 5 ◽  
pp. 286
Author(s):  
Fiona Sargison ◽  
Mariya I Goncheva ◽  
Joana Alves ◽  
Amy Pickering ◽  
J Ross Fitzgerald
Keyword(s):  
Staphylococcus Aureus ◽  
Whole Blood ◽  
Immune Cell ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Bacterial Killing ◽  
Isogenic Mutant ◽  
Extracellular Milieu ◽  
The Impact

Background: Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by S. aureus, many of which remain incompletely characterised. For example, S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown. Methods: We employed the epidemic S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on S. aureus innate immune cell escape. Results: There were no differences in the survival of S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases. Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of S. aureus with the innate immune system.

scholarly journals Olfactomedin 4 marks a subset of neutrophils in mice

2018 ◽  
Vol 25 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Matthew N Alder ◽  
Jaya Mallela ◽  
Amy M Opoka ◽  
Patrick Lahni ◽  
David A Hildeman ◽  
...  
Keyword(s):  
Innate Immune System ◽  
Immune Cell ◽  
Neutrophil Extracellular Traps ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Null Mouse ◽  
Immune Functions ◽  
Single Population ◽  
Extracellular Traps ◽  
Neutrophil Differentiation

Neutrophils are the most abundant immune cell of the innate immune system and participate in essential immune functions. Heterogeneity within neutrophils has been documented, but it is difficult to distinguish if these are altered activation states of a single population or separate subpopulations of neutrophils determined at the time of differentiation. Several groups have identified a subset of human neutrophils that express olfactomedin 4 (OLFM4) and increased OLFM4+ neutrophils during sepsis is correlated with worse outcome, suggesting these neutrophils or the OLFM4 they secrete may be pathogenic. We tested if mice could be used as a model to study OLFM4+ neutrophils. We found the OLFM4 expressing subset of neutrophils is conserved in mice. Depending on the strain, 7–35% of murine neutrophils express OLFM4 and expression is determined early in neutrophil differentiation. OLFM4+ neutrophils phagocytose and transmigrate with similar efficiency as OLFM4− neutrophils. Here we show that within neutrophil extracellular traps (NETs) OLFM4+ and OLFM4− neutrophils undergo NETosis and OLFM4 colocalizes. Finally, we generated an OLFM4 null mouse and show that these mice are protected from death when challenged with sepsis, providing further evidence that the OLFM4 expressing subpopulation of neutrophils, or the OLFM4 they secrete, may be pathogenic during overwhelming infection.

scholarly journals E-cigarette use increases susceptibility to bacterial infection by impairment of human neutrophil chemotaxis, phagocytosis, and NET formation

2020 ◽  
Vol 318 (1) ◽  
pp. C205-C214 ◽  
Author(s):  
Ross Corriden ◽  
Alexander Moshensky ◽  
Christine M. Bojanowski ◽  
Angela Meier ◽  
Jason Chien ◽  
...  
Keyword(s):  
Mouse Model ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Neutrophil Migration ◽  
Innate Immune ◽  
Innate Immune Cell ◽  
Neutrophil Extracellular Trap ◽  
Human Neutrophils ◽  
Cigarette Use ◽  
Net Production

E-cigarettes are portrayed as safer relative to conventional tobacco. However, burgeoning evidence suggests that E-cigarettes may adversely affect host defenses. However, the precise mechanisms by which E-cigarette vapor alters innate immune cell function have not been fully elucidated. We determined the effects of E-cigarette exposure on the function and responses to infectious challenge of the most abundant innate immune cell, the neutrophil, using isolated human neutrophils and a mouse model of gram-negative infection. Our results revealed that human neutrophils exposed to E-cigarette vapor had 4.2-fold reductions in chemotaxis toward the bacterial cell-well component f-Met-Leu-Phe ( P < 0.001). F-actin polarization and membrane fluidity were also adversely affected by E-cigarette vapor exposure. E-cigarette-exposed human neutrophils exhibited a 48% reduction in production of reactive oxygen species (ROS; P < 0.001). Given the central role of ROS in neutrophil extracellular trap (NET) production, NET production was quantified, and E-cigarette vapor exposure was found to reduce NETosis by 3.5-fold ( P < 0.01); formulations with and without nicotine containing propylene glycol exhibiting significant suppressive effects. However, noncanonical NETosis was unaffected. In addition, exposure to E-cigarette vapor lowered the rate of phagocytosis of bacterial bioparticles by 47% ( P < 0.05). In our physiological mouse model of chronic E-cigarette exposure and sepsis, E-cigarette vapor inhalation led to reduced neutrophil migration in infected spaces and a higher burden of Pseudomonas. These findings provide evidence that E-cigarette use adversely impacts the innate immune system and may place E-cigarette users at higher risk for dysregulated inflammatory responses and invasive bacterial infections.

scholarly journals Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms

2020 ◽  
Vol 5 ◽  
pp. 286
Author(s):  
Fiona Sargison ◽  
Joana Alves ◽  
Amy Pickering ◽  
J Ross Fitzgerald
Keyword(s):  
Staphylococcus Aureus ◽  
Whole Blood ◽  
Immune Cell ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Bacterial Killing ◽  
Isogenic Mutant ◽  
Extracellular Milieu ◽  
The Impact

Background: Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by S. aureus, many of which remain incompletely characterised. For example, S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown. Methods: We employed the epidemic S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on S. aureus innate immune cell escape. Results: There were no differences in the survival of S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases. Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of S. aureus with the innate immune system.

scholarly journals OP0286 PROTEOMICS AND RNA SEQUENCING APPROACHES HIGHLIGHT THE ROLE OF ENDOTHELIAL CELL DYSREGULATION IN IL-1 AND IFN MEDIATED AUTOINFLAMMATORY DISEASES, NOMID AND CANDLE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 178-179
Author(s):  
S. Alehashemi ◽  
M. Garg ◽  
B. Sellers ◽  
A. De Jesus ◽  
A. Biancotto ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Whole Blood ◽  
Cell Activation ◽  
Immune Cell ◽  
Differentially Expressed ◽  
Neutrophilic Dermatosis ◽  
Healthy Controls ◽  
Differentially Expressed Proteins ◽  
Rna Seq ◽  
Before And After

Background:Systemic Autoinflammatory diseases present with sterile inflammation. NOMID (Neonatal-Onset Multisystem Inflammatory Disease) is caused by gain-of-function mutations inNLRP3and excess IL-1 production, presents with fever, neutrophilic dermatosis, aseptic meningitis, hearing loss and eye inflammation; CANDLE (Chronic Atypical Neutrophilic Dermatosis, Lipodystrophy and Elevated Temperature) is caused by loss-of-function mutations in proteasome genes that lead to type-1 interferon signaling, characterized by fever, panniculitis, lipodystrophy, cytopenia, systemic and pulmonary hypertension and basal ganglia calcification. IL-1 blockers are approved for NOMID and JAK-inhibitors show efficacy in CANDLE treatment.Objectives:We used proteomic analysis to compare differentially expressed proteins in active NOMID and CANDLE compared to healthy controls before and after treatment, and whole blood bulk RNA seq to identify the immune cell signatures.Methods:Serum samples from active NOMID (n=12) and CANDLE (n=7) before and after treatment (table 1) and age matched healthy controls (HC) (n=7) were profiled using the SomaLogic platform (n=1125 proteins). Differentially expressed proteins in NOMID and CANDLE were ranked after non-parametric tests for unpaired (NOMIDp<0.05, CANDLE,p<0.1) and paired (p<0.05) analysis and assessed by enriched Gene Ontology pathways and network visualization. Whole blood RNA seq was performed (NOMID=7, CANDLE=7, Controls =5) and RPKM values were used to assess immune cells signatures.Table 1.Patient’s characteristicsNOMIDN=12, Male =6CANDLEN=7, Male =6AgeMedian (range)12 (2, 28)16 (3, 20)Ethnicity%White (Hispanic)80 (20)100 (30)GeneticsNLRP3mutation(2 Somatic, 10 Germline)mutations in proteasome component genes(1 digenic, 6 Homozygous/compound Heterozygous)Before treatmentAfter treatmentBefore treatmentAfter treatmentCRPMedian (range) mg/L52 (16-110)5 (0-23)5 (0-101)1 (0-4)IFN scoremedian (range)0NA328 (211-1135)3 (0-548)Results:Compared to control, 205 proteins (127 upregulated, 78 downregulated) were significantly different at baseline in NOMID, compared to 163 proteins (101 upregulated, and 62 downregulated) in CANDLE. 134 dysregulated proteins (85 upregulated, 49 downregulated) overlapped in NOMID and CANDLE (Figure 1). Pathway analysis identified neutrophil and monocyte chemotaxis signature in both NOMID and CANDLE. NOMID patients had neutrophilia and active neutrophils. CANDLE patients exhibited active neutrophils in whole blood RNA. Endothelial cell activation was the most prominent non-hematopoietic signature and suggest distinct endothelial cell dysregulation in NOMID and CANDLE. In NOMID, the signature included neutrophil transmigration (SELE) endothelial cell motility in response to angiogenesis (HGF, VEGF), while in CANDLE the endothelial signatures included extracellular matrix protein deposition (COL8A) suggesting increased vascular stiffness. CANDLE patients had higher expression of Renin, 4 out of 7 had hypertension, NOMID patients did not have hypertension. Treatment with anakinra and baricitinib normalized 143 and 142 of dysregulated proteins in NOMID and CANDLE respectively.Conclusion:Differentially expressed proteins in NOMID and CANDLE are consistent with innate immune cell activation. Distinct endothelial cell signatures in NOMID and CANDLE may provide mechanistic insight into differences in vascular phenotypes. Treatment with anakinra and Baricitinib in NOMID and CANDLE leaves 30% and 13% of the dysregulated proteins unchanged.Acknowledgments:This work was supported by Intramural Research atNational Institute of Allergy Immunology and Infectious Diseases of National Institutes of Health, Bethesda, Maryland, the Center of Human Immunology and was approved by the IRB.Disclosure of Interests:None declared

Serum Concentration and Skin Expression of S100A7 (Psoriasin) in Patients Suffering from Hidradenitis Suppurativa

Dermatology ◽  
2020 ◽  
pp. 1-7
Author(s):  
Aleksandra Batycka-Baran ◽  
Wojciech Baran ◽  
Danuta Nowicka-Suszko ◽  
Maria Koziol-Gałczyńska ◽  
Andrzej Bieniek ◽  
...  
Keyword(s):  
Serum Concentration ◽  
Hidradenitis Suppurativa ◽  
Protein Concentration ◽  
Normal Skin ◽  
Innate Immune ◽  
Antimicrobial Protein ◽  
Healthy Controls ◽  
Serum Concentrations ◽  
Reactive Protein

<b><i>Background:</i></b> Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. An important role of innate immune dysregulation in the pathogenesis of HS has been highlighted. S100A7 (psoriasin) is an innate, antimicrobial protein that exerts proinflammatory and chemotactic action. <b><i>Objectives:</i></b> The objective of the study was to investigate serum concentrations of S100A7 in individuals with HS as compared to healthy controls. Further, we evaluated the expression of S100A7 in lesional HS skin as compared to perilesional (clinically uninvolved) HS skin and normal skin. <b><i>Methods:</i></b> Serum concentrations of S100A7 were evaluated with a commercially available ELISA kit. The expression of S100A7 in the skin was assessed using qRT-PCR and immunofluorescence staining. <b><i>Results:</i></b> We found increased expression of S100A7 in lesional HS skin as compared to perilesional HS skin (<i>p</i> = 0.0017). The expression of S100A7 in lesional HS skin was positively associated with serum C-reactive protein concentration and the severity of disease according to Hurley staging. The serum concentration of S100A7 in individuals with HS was decreased as compared to healthy controls and patients with psoriasis. <b><i>Conclusions:</i></b> Upregulated in lesional HS skin, S100A7 may enhance the inflammatory process and contribute to the HS pathogenesis.

Sign in / Sign up

Export Citation Format

Share Document