Neutrophil Chemoattractant Research Articles

Serum C-X-C Chemokine Ligand 1 Levels in Patients with Systemic Sclerosis: Relationship of Clinical and Laboratory Observations to Anti-CD20 Monoclonal Antibody Administration.

Objectives: To determine whether C-X-C chemokine ligand 1 (CXCL1), which is a potent neutrophil chemoattractant and activator that plays important role in inflammation, is elevated in patients with systemic sclerosis (SSc) and whether it is associated with the clinical features and disease activity of patients with SSc. In addition, to determine whether the changes in serum CXCL1 levels before and after treatment correlate with changes in disease activity in SSc patients who received an anti-CD20 monoclonal antibody drug. Patients and method: We examined patient serum collected in the DesiReS trial, which was a double-blind, parallel-group, randomized, placebo-controlled, multicenter, phase II clinical trial. In the trial, patients were randomly allocated to the drug or placebo group and received 375 mg/m2 of an anti-CD20 antibody, rituximab, or placebo once a week for four weeks. We obtained serum samples from 47 patients administered at our hospital, including 3 males and 44 females, the median age of 48 years, range 27–71 years, with 42 diffuse cutaneous SSc and 5 with limited cutaneous SSc. Serum CXCL1 levels were measured using multiplex immunoassay in patient serum before and 24 weeks after administration and also in serum from 33 healthy controls. Results: Serum CXCL1 levels were significantly higher in SSc patients (mean 25.70 ng/mL; 95% confidence interval (CI) 18.35–33.05 ng/mL) than in the healthy controls (15.61 ng/mL; 95% CI 9.73–21.51 ng/mL). In addition, SSc patients with elevated CXCL1 levels had a significantly higher percentage of area occupied with interstitial shadows (p < 0.05), increased serum levels of surfactant protein (SP)-A (p < 0.05), SP-D (p < 0.05), Krebs von den Lungen-6 (p < 0.01), and C-reactive protein (p < 0.05) compared to those with normal levels. Furthermore, defining Δ as the value after rituximab administration minus the value before rituximab administration, baseline serum CXCL1 levels correlated with Δ percent predicted diffusing capacity for carbon monoxide (p < 0.01). In addition, ΔCXCL1 correlated with ΔSP-A (p < 0.05). Similarly, serum CXCL1 levels after rituximab administration correlated with percent predicted forced vital capacity (p < 0.05) and serum SP-D levels (p < 0.05) after rituximab. Conclusions: Our results suggest that serum CXCL1 is associated with the disease activity of SSc-ILD, and high serum CXCL1 levels are one of the predictors of improvement in SSc-ILD with rituximab.

The Importance of CXCL1 in Physiology and Noncancerous Diseases of Bone, Bone Marrow, Muscle and the Nervous System.

This review describes the role of CXCL1, a chemokine crucial in inflammation as a chemoattractant for neutrophils, in physiology and in selected major non-cancer diseases. Due to the vast amount of available information, we focus on the role CXCL1 plays in the physiology of bones, bone marrow, muscle and the nervous system. For this reason, we describe its effects on hematopoietic stem cells, myoblasts, oligodendrocyte progenitors and osteoclast precursors. We also present the involvement of CXCL1 in diseases of selected tissues and organs including Alzheimer’s disease, epilepsy, herpes simplex virus type 1 (HSV-1) encephalitis, ischemic stroke, major depression, multiple sclerosis, neuromyelitis optica, neuropathic pain, osteoporosis, prion diseases, rheumatoid arthritis, tick-borne encephalitis (TBE), traumatic spinal cord injury and West Nile fever.

Differential effects of the soluble fiber inulin in reducing adiposity and altering gut microbiome in aging mice

Inulin, a soluble dietary fiber, is thought to exert multiple beneficiary effects through promoting growth of bacteria that metabolize the fiber to short-chain fatty acids (SCFAs); however, the effect and efficacy of inulin in aging subjects is unknown. This study aims to systematically evaluate the capacity of SCFAs production and host response in mice of different ages. Male C57BL/6J mice across young (5 months), middle (11 months) and old (26 months) age were subjected to a control diet for 2 weeks, followed by 6 weeks of inulin-containing diet. Inulin-induced increase in fecal butyric acid levels was most prominent in middle-age group compared to other age groups. In addition, inulin-induced increase in fecal propionic acids showed age-dependent decline. Interestingly, the SCFA-producing Roseburia was most abundantly and persistently increased in the middle-age group. Furthermore, inulin intake significantly reduced Firmicutes to Bacteroidetes ratio, and several dysbiotic bacteria associated with pro-inflammatory state. Concomitantly, circulating levels of CXCL1, a chemoattractant for neutrophils, was reduced by inulin intake. Inulin decreased fat mass in all age groups, with middle-aged mice being most responsive to fat-reducing effects of inulin. Moreover, inulin significantly increased energy expenditure and voluntary wheel running in middle-aged mice, but not in old mice. Overall, our data suggest that the efficacy of inulin in altering the microbiome and SCFA production, and the subsequent metabolic response was diminished in old mice, and highlight the importance of including age as a variable in studies determining host-microbe response to diets.

Chemokine (C-X-C motif) ligand 1 maintains the immune surveillance function of natural killer cells via the PDK2/mTOR signaling pathway.

Chemokine (C-X-C motif) ligand 1 (CXCL1) is mainly expressed on neutrophils and macrophages and has neutrophil chemoattractant activity. However, natural killer (NK) cells also express CXCL1. We were curious about the role played by CXCL1 in NK cells. Knocking out CXCL1 in hematopoietic cells does not affect the occurrence of NK cells; however, it does hinder NK cell maturity. CXCL1 deletion enhances the expression of immature markers and decreases the expression of functional markers in NK cells, which may explain why it hinders the maturation of NK cells. Specific knockout of CXCL1 in NK cells (CXCL1flox/flox Ncr1-cre) leads to impaired IFN-γ production and degranulation of NK cells. The lack of CXCL1 may prevent IFN-γ production and degranulation of NK cells by inhibiting the phosphorylation of AKTS473 and S6. Therefore, we have discovered a new role for CXCL1 in regulating NK cell development and immune surveillance, providing a novel theoretical basis for immunotherapy based on NK cells and potential therapeutic targets for the clinical use of NK cells. 1. Knockout of CXCL1 in hematopoietic cells inhibits the maturation of NK cells. 2. Knockout of CXCL1 in NK cells inhibits the clearance of lymphoma by NK cells and reduces IFN-γ production and CD107 expression in NK cells. 3. CXCL1 activates the PKD2/mTOR signaling pathway, and promotes the production of IFN-γ and the expression of CD107a in NK cells.

RGMa Signal in Macrophages Induces Neutrophil-Related Astrocytopathy in NMO.

Repulsive guidance molecule-a (RGMa) is a glycosylphosphatidylinositol-linked glycoprotein which has multiple functions including axon growth inhibition and immune regulation. However, its role in the pathophysiology of neuromyelitis optica (NMO) is poorly understood. Perivascular astrocytopathy, which is induced by the leakage of aquaporin-4 (AQP4)-specific IgG into the central nervous system parenchyma, is a key feature of NMO pathology. We investigated the RGMa involvement in the pathology of NMO astrocytopathy, and tested a therapeutic potential of humanized anti-RGMa monoclonal antibody (RGMa-mAb). Using a clinically relevant NMO rat model, we evaluated the therapeutic effect of a RGMa-mAb by behavioral testing, immunohistochemistry, and gene expression assay. We further performed in vitro experiments to address the RGMa-signaling in macrophages. In both NMO rats and an NMO-autopsied sample, RGMa was expressed by the spared neurons and astrocytes, whereas its receptor neogenin was expressed by infiltrating macrophages. AQP4-IgG-induced astrocytopathy and clinical exacerbation in NMO rats were ameliorated by RGMa-mAb treatment. RGMa-mAb treatment significantly suppressed neutrophil infiltration, and decreased the expression of neutrophil chemoattractants. Interestingly, neogenin-expressing macrophages accumulated in the lesion expressed CXCL2, a strong neutrophil chemoattractant, and further analysis revealed that RGMa directly regulated CXCL2 expression in macrophages. Finally, we found that our NMO rats developed neuropathic pain, and RGMa-mAb treatment effectively ameliorated the severity of neuropathic pain. RGMa signaling in infiltrated macrophages is a critical driver of neutrophil-related astrocytopathy in NMO lesions, and RGMa-mAb may provide an efficient therapeutic strategy for NMO-associated neuropathic pain and motor deficits in patients with NMO. ANN NEUROL 2022;91:532-547.

Macrophage migration inhibitory factor regulates specific innate immune sensor responses in gingival epithelial cells.

The gingival epithelium protects periodontal tissues and the alveolar bone by maintaining a steady state of regulated inflammatory surveillance, also known as healthy homeostasis. Accordingly, the repertoire of receptors present within the gingival epithelium showcases its ability to recognize microbial colonization and contribute to bacterial sensing. Macrophage migration inhibitory factor (MIF) is one of many cytokines that are expressed in this protective state and is involved in neutrophil regulation. However, its role in the maintenance of healthy gingival tissue has not been described. Gingival tissues from wild-type (WT) and Mif knock-out (KO) mice were stained for neutrophils and three key neutrophil chemoattractants: MIF, Gro-α/CXCL1, and Gro-β/CXCL2 in the junctional epithelium (JE). In addition, gene silencing studies were performed using gingival epithelial cells (GECs) to examine the role of MIF on transcription of key bacterial recognition receptors Toll-like receptors (TLR)-1, -2, -4, -6, -9 and interleukin-1 receptors (IL-1R1 and IL-1R2) in response to oral bacterial stimulation. WT murine gingival tissues demonstrated high expression of MIF in the JE. In Mif KO mice, despite the significant reduction of Gro-α/CXCL1 and Gro-β/CXCL2, there was a slight increase in neutrophils. Gene silencing experiments showed that MIF down-regulated the mRNA expression of TLR4, IL-1R1, and IL-1R2 in GEC, in addition to decreasing secreted IL-8/CXCL8 in response to bacteria. MIF regulates the expression of TLR4, IL-1Rs, and IL-8/CXCL8, components that are all involved in maintaining oral health. Our data demonstrate that MIF is a significant contributor to the maintenance of healthy oral homeostasis.

Isoflurane attenuates sepsis-associated lung injury

Acute lung injury is one of major complications associated with sepsis, responsible for morbidity and mortality. Patients who suffer from acute lung injury often require respiratory support under sedations, and it would be important to know the role of sedatives in lung injury. We examined volatile anesthetic isoflurane, which is commonly used in surgical setting, but also used as an alternative sedative in intensive care settings in European countries and Canada. We found that isoflurane exposure attenuated neutrophil recruitment to the lungs in mice suffering from experimental polymicrobial abdominal sepsis. We found that isoflurane attenuated one of major neutrophil chemoattractants LTB4 mediated response via its receptor BLT1 in neutrophils. Furthermore, we have shown that isoflurane directly bound to BLT1 by a competition assay using newly developed labeled BLT1 antagonist, suggesting that isoflurane would be a BLT1 antagonist.

GPR35 promotes neutrophil recruitment in response to serotonin metabolite 5-HIAA

Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils are less recruited from blood vessels into inflamed tissue, and the mice are less efficient in clearing peritoneal bacteria. Using a bioassay, we find that serum and activated platelet supernatant stimulate GPR35, and we identify the platelet-derived serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) as a GPR35 ligand. GPR35 function in neutrophil recruitment is strongly dependent on platelets, with the receptor promoting transmigration across platelet-coated endothelium. Mast cells also attract GPR35+ cells via 5-HIAA. Mice deficient in 5-HIAA show a loss of GPR35-mediated neutrophil recruitment to inflamed tissue. These findings identify 5-HIAA as a GPR35 ligand and neutrophil chemoattractant and establish a role for platelet- and mast cell-produced 5-HIAA in cell recruitment to the sites of inflammation and bacterial clearance.

Pseudomonas aeruginosa adaptation in cystic fibrosis patients increases C5a levels and promotes neutrophil recruitment

ABSTRACT Cystic fibrosis (CF) disease is characterized by an intense airway inflammatory response mediated by neutrophils and chronic respiratory infections caused by P. aeruginosa. High levels of the complement component C5a, the strongest neutrophil chemoattractant molecule, are commonly found in the CF lung and have been associated with a worsening of the disease. In this study, we investigated how the isolates from CF patients modulate the levels of C5a and identified the bacterial factors involved. We demonstrated that most isolates from airway chronic infections induce the production and accumulation of C5a, an effect attributable to the loss of C5a cleavage by the exoproteases alkaline protease (AprA) and elastase B (LasB). Furthermore, we found that lack of the bacterial protease-dependent C5a degradation is due to mutations in the master regulator LasR. Thus, complementation of a non-C5a-cleaving CF isolate with a functional wild-type LasR restored its ability to express both proteases, cleave C5a and reduce neutrophil recruitment in vitro. These findings suggest that the non-cleaving C5a phenotype acquired by the LasR variants frequently isolated in CF patients may account for the strong neutrophilia and general neutrophil dysfunction predisposing toward increased inflammation and reduced bacterial clearance described in CF patients.

Toll-like receptor 2 and 6 agonist fibroblast-stimulating lipopeptide increases expression and secretion of CXCL1 and CXCL2 by uveal melanocytes

Fibroblast-stimulating lipopeptide (FSL-1) can activate Toll-like receptor 2 and 6 (TLR2/6), which recognize relevant molecules from gram-positive pathogens, fungus, and mycoplasma, and elevates the expression of CXCL1 and CXCL2, neutrophil chemoattractants, in certain types of cells. This effect has not previously been reported in the uveal melanocytes (UM). This study was designed to test the hypothesis that FSL-1 can induce the expression and secretion of CXCL1 and CXCL2 via activation of TLR2/6 in cultured human UM and producing an acute non-infectious uveitis reaction in the mouse. Flow cytometry and fluorescent immunostaining were used to measure the effect of FSL-1 on the expression of TLR2/6 in UM. Real time PCR and ELISA analysis were used to assess the ability of FSL-1 to elevate CXCL1/CXCL2 levels in cell lysates and conditioned media of UM, respectively. Flow cytometry measured phosphorylated MAPK and activated NF-κB signals in UM, with and without FSL-1 treatment. ELISA analysis tested the impact of various signal inhibitors (NF-κB, p38 MAPK, JNK1/2 and ERK1/2) and TLR2/6 antagonists on FSL-1-induced CXCL1/CXCL2 levels in cultured UM. The effects of neutralizing antibodies to TLR2 on FSL-1-induced mouse uveitis were tested in an experimental animal model. FSL-1 induced the expression of TLR2/6 proteins in cultured UM. FSL-1 significantly elevated the CXCL1 and CXCL2 proteins and mRNA levels in cultured UM time- and dose-dependently. FSL-1 mainly activated NF-κB, JNK, and expression of TLR2. FSL-1-induced expression of CXCL1 and CXCL2 was blocked by NF-κB, JNK, ERK inhibitors and TLR2 antagonists. Intravitreal injection of FSL-1 induced acute non-infectious mouse uveitis, which was significantly reduced in severity by a TLR2 antagonist. These results suggest that UM may play a role in the immune reaction, which targets invading pathogens, especially gram-positive bacteria. On the other hand, an excessive reaction to molecules from gram-positive bacteria may promote an inflammatory state of non-infectious uveitis.

Inflammogenic effect of polyacrylic acid in rat lung following intratracheal instillation

BackgroundSome organic chemicals are known to cause allergic disorders such as bronchial asthma and hypersensitivity pneumonitis, and it has been considered that they do not cause irreversible pulmonary fibrosis. It has recently been reported, however, that cross-linked acrylic acid-based polymer, an organic chemical, might cause serious interstitial lung diseases, including pulmonary fibrosis. We investigated whether or not intratracheal instillation exposure to cross-linked polyacrylic acid (CL-PAA) can cause lung disorder in rats.MethodsMale F344 rats were intratracheally instilled with dispersed CL-PAA at low (0.2 mg/rat) and high (1.0 mg/rat) doses, and were sacrificed at 3 days, 1 week, 1 month, 3 months and 6 months after exposure to examine inflammatory and fibrotic responses and related gene expressions in the lungs. Rat lungs exposed to crystalline silica, asbestos (chrysotile), and NiO and CeO2 nanoparticles were used as comparators.ResultsPersistent increases in total cell count, neutrophil count and neutrophil percentage, and in the concentration of the cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2 and C-X-C motif chemokine 5 (CXCL5), which correlated with lung tissue gene expression, were observed in bronchoalveolar lavage fluid (BALF) from 3 days until at least 1 month following CL-PAA intratracheal instillation. Persistent increases in heme oxygenase-1 (HO-1) in the lung tissue were also observed from 3 days to 6 months after exposure. Histopathological findings of the lungs demonstrated that extensive inflammation at 3 days was greater than that in exposure to silica, NiO nanoparticles and CeO2 nanoparticles, and equal to or greater than that in asbestos (chrysotile) exposure, and the inflammation continued until 1 month. Fibrotic changes also progressed after 1 month postexposure.ConclusionOur results suggested that CL-PAA potentially causes strong neutrophil inflammation in the rat and human lung.

Severe Neutrophilic Asthma: Pathogenesis and Treatment

Asthma is a common chronic airway disease affecting about 358 million people worldwide, and an estimated 7 million children globally. Approximately 10% of patients with asthma have severe refractory disease, which is difficult to control on high doses of inhaled corticosteroids and other modifiers. Among these, are patients with severe neutrophilic asthma. Neutrophilic asthma is a severe phenotype of asthma, characterized by frequent exacerbations, persistent airway obstruction, and poor lung function. Immunopathologically, it is characterized by the presence of high levels of neutrophils in the airways and lungs. Interleukin-17 produced by Th17 cells, plays a key role in the pathogenesis of neutrophilic asthma by expressing the secretion of chemoattractant cytokines and chemokines for the recruitment, and activation of neutrophils. Interleukin-8 is a powerful chemoattractant and activator of neutrophils. Activated neutrophils produce an oxidative burst, releasing multiple reactive oxygen species, proteinases, cytokines, which cause airway epithelial cell injury, inflammation, airway hyperresponsiveness, and remodeling. Furthermore, exasperated neutrophils due to viral, bacterial or fungal infections, and chemical irritants can release extracellular nucleic acids (DNA), designated as NETs (neutrophil extracellular traps), which are more toxic to the airway epithelial cells, and orchestrate airway inflammation, and release alarmin cytokines. Dysregulated NETs formation is associated with severe asthma. Most patients with neutrophilic asthma are unresponsive to the standard of care, including high dose inhaled corticosteroids, and to targeted biologics, such as mepolizumab, and dupilumab, which are very effective in treating eosinophilic asthma. There is unmet need to explore for novel biologics for the treatment of neutrophilic asthma, and in refining therapies, such as bronchial thermoplasty.

Pulmonary disorder induced by cross-linked polyacrylic acid.

Organic polymers are materials widely used in our daily lives, such as daily necessities, foods, and medicines. There have been reports recently that cross-linked polyacrylic acid (CL-PAA) can possibly cause serious lung disease. We investigated whether intratracheal instillation of CL-PAA causes pulmonary disorder in rats. Male F344 rats were administered low (0.2mg/rat) and high (1.0mg/rat) doses of CL-PAA intratracheally and were dissected 3 days, 1week, 1month, 3months, and 6months after exposure to examine inflammatory and fibrotic responses in the lungs. Only the high-dose specimens were subjected to ultrasonic dispersion treatment of the administered material. There was a dose-dependent increase in the total cell count, neutrophil count, neutrophil percentage, lactate dehydrogenase (LDH), surfactant protein D (SP-D), cytokine-induced neutrophil chemoattractant (CINC)-1 and CINC-2 values in bronchoalveolar lavage fluid (BALF) from 3 days to at least 3months after intratracheal administration of CL-PAA. Heme oxygenase-1 (HO-1) in lung tissue was also persistently elevated from 3 days to 6months after exposure. Alkaline phosphatase (ALP) in BALF was elevated at 3 days and 1month after exposure only in the high-dose group. Histopathological findings in lung tissue showed inflammatory and fibrotic changes from 3 days after administration, and we observed obvious inflammatory changes for up to 3months and fibrotic changes for up to 6months. Intratracheal administration of CL-PAA induced persistent neutrophilic inflammation and fibrosis in the rats' lungs, suggesting that CL-PAA may have inflammogenic and fibrogenic effects.

Pulmonary toxicity of tungsten trioxide nanoparticles in an inhalation study and an intratracheal instillation study.

We conducted inhalation and intratracheal instillation studies in order to examine the effects of tungsten trioxide (WO3 ) nanoparticles on the lung, and evaluated whether or not the nanoparticles would cause persistent lung inflammation. In the inhalation study, male 10-week-old Fischer 334 rats were classified into 3 groups. The control, low-dose, and high-dose groups inhaled clean air, 2,and 10mg/m3 WO3 nanoparticles, respectively, for 6h each day for 4 weeks. The rats were dissected at 3 days, 1month, and 3months after the inhalation, and the bronchoalveolar lavage fluid (BALF) and lung tissue were examined. In the intratracheal instillation study, male 12-week-old Fischer 334 rats were divided into 3 subgroups. The control, low-dose, and high-dose groups were intratracheally instilled 0.4ml distilled water, 0.2, and 1.0mg WO3 nanoparticles, respectively, dissolved in 0.4mldistilled water. The rats were sacrificed at 3 days, 1week, and 1month after the intratracheal instillation, and the BALF and lung tissue were analyzed as in the inhalation study. The inhalation and instillation of WO3 nanoparticles caused transient increases in the number and rate of neutrophils, cytokine-induced neutrophil chemoattractant (CINC)-1, and CINC-2 in BALF, but no histopathological changes or upregulation of heme oxygenase (HO)-1 in the lung tissue. Our results suggest that WO3 nanoparticles have low toxicity to the lung. According to the results of the inhalation study, we also propose that the no observed adverse effect level (NOAEL) of WO3 nanoparticles is 2mg/m3 .

Gram-Negative Bacteria Salmonella typhimurium Boost Leukotriene Synthesis Induced by Chemoattractant fMLP to Stimulate Neutrophil Swarming.

Leukotriene synthesis in neutrophils is critical for host survival during infection. In particular, leukotriene B4 (LTB4) is a powerful neutrophil chemoattractant that plays a crucial role in neutrophil swarming. In this work, we demonstrated that preincubation of human neutrophils with Salmonella typhimurium strongly stimulated LTB4 production induced by the bacterial chemoattractant, peptide N-formyl-L-methionyl-L-leucyl-l-phenylalanine (fMLP), while the reverse sequence of additions was ineffective. Preincubation with bacterial lipopolysaccharide or yeast polysaccharide zymosan particles gives weaker effect on fMLP-induced LTB4 production. Activation of 5-lipoxygenase (5-LOX), a key enzyme in leukotrienes biosynthesis, depends on rise of cytosolic concentration of Ca2+ and on translocation of the enzyme to the nuclear membrane. Both processes were stimulated by S. typhimurium. With an increase in the bacteria:neutrophil ratio, the transformation of LTB4 to ω-OH-LTB4 was suppressed, which further supported increased concentration of LTB4. These data indicate that in neutrophils gathered around bacterial clusters, LTB4 production is stimulated and at the same time its transformation is suppressed, which promotes neutrophil swarming and elimination of pathogens simultaneously.

Are interleukin 6 and LTB4 measurements in exhaled breath of COVID-19 and post-COVID-19 lung fibrosis patients easy, sensitive and useful indicators of the intensity of airway inflammation and fibrosis?

Many studies pointed to il-6 as hall marker for severity and prognosis of covid-19 patients and represent the most important cornerstone at the discovery of many drugs for inhibition of it for switch-off of cytokine storm which is the concern of all scientists and patients together and a new disease at future medicine as covid-19 begin at last of December 2019. The sources of il-6 after viral stimulation are from macrophages and monocytes at many inflammatory sites or from stimulation of the HPA axis (endocrine il-6 ACTH stimulated) or respiratory il-6 stimulated by strenuous resistive breathing because contracting of respiratory muscles is considered like exercise and produce cytokines due to glycogen depletion The Discovery of a non-invasive and easy method to examine il-6 which is the most important marker for severity and cytokine storm represent a new horizon for future viruses and modern medicine and that accelerates the intervention and depression of cytokine storm as early as possible and open the door for the discovery of many drugs work on this exhaled il-6 so our method for examination of il-6 at exhaled of covid and postcovid-19 patients help doctors for rapid categorization of patients and suspicion of severity. So, our study is a novel method for examination of il-6 Herein we intend to investigate the level of IL-6 in a breath of COVID-19 patients for the diagnosis of the early stages of lung inflammation and fibrosis. LTB4 is a potent chemoattractant and stimulator of neutrophils, without any significant effect on airway muscle. And increased in exhaled of children with mild and moderate to severe persistent asthma.

Cigarette smoke exposed airway epithelial cell-derived EVs promote pro-inflammatory macrophage activation in alpha-1 antitrypsin deficiency

BackgroundAlpha-1 antitrypsin deficiency (AATD) is a genetic disorder most commonly secondary to a single mutation in the SERPINA1 gene (PI*Z) that causes misfolding and accumulation of alpha-1 antitrypsin (AAT) in hepatocytes and mononuclear phagocytes which reduces plasma AAT and creates a toxic gain of function. This toxic gain of function promotes a pro-inflammatory phenotype in macrophages that contributes to lung inflammation and early-onset COPD, especially in individuals who smoke cigarettes. The aim of this study is to determine the role of cigarette exposed AATD macrophages and bronchial epithelial cells in AATD-mediated lung inflammation.MethodsPeripheral blood mononuclear cells from AATD and healthy individuals were differentiated into alveolar-like macrophages and exposed to air or cigarette smoke while in culture. Macrophage endoplasmic reticulum stress was quantified and secreted cytokines were measured using qPCR and cytokine ELISAs. To determine whether there is “cross talk” between epithelial cells and macrophages, macrophages were exposed to extracellular vesicles released by airway epithelial cells exposed to cigarette smoke and their inflammatory response was determined.ResultsAATD macrophages spontaneously produce several-fold more pro-inflammatory cytokines as compared to normal macrophages. AATD macrophages have an enhanced inflammatory response when exposed to cigarette smoke-induced extracellular vesicles (EVs) released from airway epithelial cells. Cigarette smoke-induced EVs induce expression of GM-CSF and IL-8 in AATD macrophages but have no effect on normal macrophages. Release of AAT polymers, potent neutrophil chemo attractants, were also increased from AATD macrophages after exposure to cigarette smoke-induced EVs.ConclusionsThe expression of mutated AAT confers an inflammatory phenotype in AATD macrophages which disposes them to an exaggerated inflammatory response to cigarette smoke-induced EVs, and thus could contribute to progressive lung inflammation and damage in AATD individuals.

Complement activation induces excessive T cell cytotoxicity in severe COVID-19

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

Omeprazole Increases Survival Through the Inhibition of Inflammatory Mediaters in Two Rat Sepsis Models.

ABSTRACTBackground:Omeprazole (OMZ) is a proton pump inhibitor that is used to reduce gastric acid secretion, but little is known about its possible liver protective effects. This study investigated whether OMZ has beneficial effects in rat septic models of LPS-induced liver injury after D-galactosamine (GalN) treatment and 70% hepatectomy (PH), and to determine the mechanisms of OMZ in an in vitro model of liver injury.Methods:In the in vivo models, the effects of OMZ were examined 1 h before treatments in both models on survival, nuclear factor (NF)-κB activation, histopathological analysis, and proinflammatory mediator expression in the liver and serum. In the in vitro model, primary cultured rat hepatocytes were treated with IL-1β in the presence or absence of OMZ. The influence of OMZ on nitric oxide (NO) product and inducible NO synthase (iNOS) induction and on the associated signaling pathway was analyzed.Results:OMZ increased survival and decreased tumor necrosis factor-alpha, iNOS, cytokine-induced neutrophil chemoattractant 1, IL-6, and IL-1β mRNA expression, and increased IL-10 mRNA expression in the livers of both GaIN/LPS- and PH/LPS-treated rats. Necrosis and apoptosis were inhibited by OMZ in GaIN/LPS rats, but OMZ had no effects on necrosis in PH/LPS rats. OMZ inhibited iNOS induction partially through suppression of NF-κB signaling in hepatocytes.Conclusions:OMZ inhibited the induction of several inflammatory mediators, resulting in the prevention of LPS-induced liver injury after GalN liver failure and PH, although OMZ showed different doses and mechanisms in the two models.

Adenovirus Co-Opts Neutrophilic Inflammation to Enhance Transduction of Epithelial Cells.

Human adenoviruses (HAdV) cause a variety of infections in human hosts, from self-limited upper respiratory tract infections in otherwise healthy people to fulminant pneumonia and death in immunocompromised patients. Many HAdV enter polarized epithelial cells by using the primary receptor, the Coxsackievirus and adenovirus receptor (CAR). Recently published data demonstrate that a potent neutrophil (PMN) chemoattractant, interleukin-8 (IL-8), stimulates airway epithelial cells to increase expression of the apical isoform of CAR (CAREx8), which results in increased epithelial HAdV type 5 (HAdV5) infection. However, the mechanism for PMN-enhanced epithelial HAdV5 transduction remains unclear. In this manuscript, the molecular mechanisms behind PMN mediated enhancement of epithelial HAdV5 transduction are characterized using an MDCK cell line that stably expresses human CAREx8 under a doxycycline inducible promoter (MDCK-CAREx8 cells). Contrary to our hypothesis, PMN exposure does not enhance HAdV5 entry by increasing CAREx8 expression nor through activation of non-specific epithelial endocytic pathways. Instead, PMN serine proteases are responsible for PMN-mediated enhancement of HAdV5 transduction in MDCK-CAREx8 cells. This is evidenced by reduced transduction upon inhibition of PMN serine proteases and increased transduction upon exposure to exogenous human neutrophil elastase (HNE). Furthermore, HNE exposure activates epithelial autophagic flux, which, even when triggered through other mechanisms, results in a similar enhancement of epithelial HAdV5 transduction. Inhibition of F-actin with cytochalasin D partially attenuates PMN mediated enhancement of HAdV transduction. Taken together, these findings suggest that HAdV5 can leverage innate immune responses to establish infections.