Ivermectin Affects Neutrophil-Induced Inflammation through Inhibition of Hydroxylysine but Stimulation of Cathepsin G and Phenylalanine Secretion.

The invasion and integrin-dependent adhesion of neutrophils to lung tissues and their secretion lead to the development of pneumonia in various pulmonary pathologies, including acute respiratory distress syndrome in coronavirus disease. We studied the effect of ivermectin, a possible therapeutic agent for inflammation and cancer, on integrin-dependent neutrophil adhesion to fibronectin and the concomitant secretion. Ivermectin did not affect the attachment of neutrophils to the substrate and the reactive oxygen species production but sharply inhibited the adhesion-induced release of hydroxylysine and stimulated the release of phenylalanine and cathepsin G. Hydroxylysine is a product of lysyl hydroxylase, which is overexpressed in tumor cells with an increased ability to invade and metastasize. The inhibition of hydroxylysine release by ivermectin, by analogy, may indicate the suppression of neutrophil invasion into tissue. The increase in the release of phenylalanine in our experiments coincided with the secretion of cathepsin G, which indicates the possible role of this enzyme in the cleavage of phenylalanine. What is the substrate in such a reaction is unknown. We demonstrated that exogenously added angiotensin II (1-8) can serve as a substrate for phenylalanine cleavage. Mass spectrometry revealed the formation of angiotensin II (1-7) in the secretion of neutrophils, which attached to fibronectin in the presence of ivermectin and exogenous angiotensin II (1-8), indicating a possible involvement of ivermectin in the inactivation of angiotensin II.

Composition decipherment of Ficus pumila var. awkeotsang and its potential on COVID-19 symptom amelioration and in silico prediction of SARS-CoV-2 interference

The jelly from achenes of Ficus pumila var. awkeotsang (FPAA) is a famous beverage ingredient in Taiwan. In this work, ficumarin (1), a new compound was obtained from its twigs (FPAT) and elucidated with comprehensive spectroscopic data. The biosynthetic origin was proposed from the p-coumaroyl-CoA pathway. Alloxanthoxyletin, betulinic acid, and catechin were identified as the major and active constituents responsible for relieving neutrophilic inflammation by FPAT. Among them, the most potent alloxanthoxyletin was found to interact with PRO350 and GLU377 of human INOSOX. Further, Nrf2 activating capacity of the FPAT fraction and its coumarins was confirmed. With the analysis of LC-MS/MS data and feature-based molecular networking, coumarins were found as the dominant and responsible components. Notably, alloxanthoxyletin increased Nrf2 expression by up to 816.8 +/- 58% due to the interacting with the VAL561, THR560 and VAL420 residues of 5FNQ protein. COVID-19 Docking Server simulation indicated that pyranocoumarins would promisingly interfere with the life cycle of SARS-CoV-2. FPAT was proven to exert. Copyright © 2022 Taiwan Food and Drug Administration.

Hyperinflammatory ARDS Is Characterized by Interferon-High, Neutrophil-Predominant Inflammation in the Lower Respiratory Tract

Background: Latent class analyses in patients with acute respiratory distress syndrome (ARDS) have identified “hyper-inflammatory” and “hypo-inflammatory” phenotypes with divergent clinical outcomes and treatment responses. ARDS phenotypes are defined using plasma biomarkers and clinical variables. It is currently unknown if these phenotypes have distinct pulmonary biology and if pre-clinical models of disease replicate the biology of either phenotype. Methods: 45 subjects with ARDS (Berlin Definition) and 5 mechanically ventilated controls were selected from cohorts of mechanically ventilated patients at UCSF and ZSFG. Patients with COVID-19 were excluded from this analysis. A 3-variable classifier model (plasma IL-8, protein C, and bicarbonate;Sinha 2020) was used to assign ARDS phenotypes. Tracheal aspirate (TA) RNA was analyzed using established bulk and single-cell sequencing pipelines (Langelier 2018, Sarma 2021). Differentially expressed (DE) genes were analyzed using Ingenuity Pathway Analysis (IPA). Microbial community composition was analyzed with vegan. Fgsea was used to test for enrichment of gene sets from experimental ARDS models in genes that were differentially expressed between each phenotype and mechanically ventilated controls. Results: Bulk RNA sequencing (RNAseq) was available from 29 subjects with hypoinflammatory ARDS and 10 subjects with hyperinflammatory ARDS. 2,777 genes were differentially expressed between ARDS phenotypes. IPA identified several candidate upstream regulators of gene expression in hyperinflammatory ARDS including IL6, TNF, IL17C, and interferons (Figure 1A). 2,953 genes were differentially expressed between hyperinflammatory ARDS and 5 ventilated controls;in contrast, only 243 genes were differentially expressed between hypoinflammatory ARDS and controls, suggesting gene expression in the hypoinflammatory phenotype was more heterogeneous. Gene sets from experimental models of acute lung injury were enriched in hyperinflammatory ARDS but not in hypoinflammatory ARDS (Figure 1B). Single cell RNA sequencing (scRNAseq) was available from 6 additional subjects with ARDS, of whom 3 had hyperinflammatory ARDS. 14,843 cells passed quality control filters. Hyperinflammatory ARDS subjects had a markedly higher burden of neutrophils (Figure 1C), including a cluster of stressed neutrophils expressing heat shock protein RNA that was not present in hypoinflammatory ARDS. Expression of a Th1 signature was higher in T cells from hyperinflammatory ARDS. Differential expression analysis in macrophages identified increased expression of genes associated with mortality in a previous study of ARDS patients (Morell 2019). Conclusions: The respiratory tract biology of ARDS phenotypes is distinct. Hyperinflammatory ARDS is characterized by neutrophilic inflammation with distinct immune cell polarization. Transcriptomic profiling identifies candidate preclinical disease models that replicate gene expression observed in hyperinflammatory ARDS.

Istradefylline, an adenosine A2a receptor antagonist, inhibits the CD4+ T-cell hypersecretion of IL-17A and IL-8 in humans.

Extracellular adenosine produced from ATP plays a role in energy processes, neurotransmission, and inflammatory responses. Istradefylline is a selective adenosine A2a receptor (A2aR) antagonist used for the treatment of Parkinson's disease. We previously showed using mouse models that adenosine primes hypersecretion of interleukin (IL)-17A via A2aR, which plays a role in neutrophilic inflammation models in mice. This finding suggests that adenosine is an endogenous modulator of neutrophilic inflammation. We, therefore, investigated the in vitro effect of istradefylline in humans. In the present study, using human peripheral blood mononuclear cells (PBMCs), we tested the effect of adenosine, adenosine receptor agonists and istradefylline on cytokine responses using mixed lymphocyte reaction (MLR), PBMCs, CD4+ T cells, and Candida albicans antigen (Ag)-stimulated PBMCs. We showed that adenosine and an A2aR agonist (PSB0777) promoted IL-17A and IL-8 production from human PBMCs, and istradefylline suppressed this response. In addition, istradefylline inhibited not only the IL-17A and IL-8 production induced by adenosine but also that from C. albicans Ag-stimulated PBMCs. These results indicate that adenosine-mediated IL-17A and IL-8 production plays a role in neutrophilic inflammation, against which istradefylline should be effective.

Bacterial components suppress experimental acute lung injury through regulatory T-cells

Introduction: The induction of regulatory T cells (Tregs) is indicated as a potential therapeutic strategy in inflammatory lung diseases including, asthma, viral-induced pneumonia, viral-induced acute lung injury (ALI), severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and SARSCoV- 2-induced ALI. We previously identified that components of the bacteria Streptococcus pneumoniae (T + P) are able to increase Tregs to suppress experimental allergic airways disease, however, this mechanism of suppression and therapy has not been examined in ALI. Methods: We established a murine model of ALI using aerosolized LPS (100 μg/ml) in BALB/c mice. ALI was measured by the presence of neutrophils in the airways up to 96 hours post-exposure, and Tregs and dendritic cells were assessed by flow cytometry. To assess the therapeutic of T + P in ALI and the mechanisms involved, the combination was administered prior to LPS exposure in the absence or presence of anti-CD25. Results: Treatment with T + P significantly reduced total airway inflammation and suppressed the neutrophil chemokine C-X-C motif chemokine ligand 1 (Cxcl1) compared to Saline+LPS alone in experimental ALI. The numbers of Tregs were reduced in experimental ALI model and were restored by T + P treatment. Depletion of Tregs with anti- CD25 confirmed that the suppressive effects of T + P on ALI was through the induction of Tregs. Conclusion: Treatment with S. pneumoniae components T + P suppresses neutrophilic inflammation in ALI through immunoregulatory mechanisms that involve Tregs and may be a novel treatment for ALI including in COVID-19.