Project description:Primary objectives: This study aims at (further) revealing the pathophysiology of intestinal IR in man, with a specific interest for the role of proteases and protease-activated receptor-2 (PAR-2), cellular and inflammatory changes, barrier function and intestinal permeability, microscopic mucosal changes and gene expression patterns. An important element will be the determination of the effects of protease- and MMP inhibitors. By these means we hope to identify preventive and therapeutic strategies for patients with intestinal IR.
Primary endpoints: The primary endpoint in this study is inflammation (neutrophil influx, complement activation, interleukins, TNF-α, COX 1-2) and protease activity in tissue as well as in blood plasma.
Project description:Myeloperoxidase (MPO), an important diprotomeric glycoprotein in neutrophil-mediated immunity, produces microbicidal hypohalous acids, but the underpinning glycobiology remains elusive. Deep characterisation of neutrophil-derived MPO (nMPO) using advanced mass spectrometry demonstrated that under-processed oligomannosidic- and hyper-truncated paucimannosidic- and N-acetyl-β-D-glucosamine (GlcNAc) core-type asparagine-linked glycans decorate the protein. Occlusion of Asn355 and Asn391 and sterical hindrance of Asn323- and Asn483-glycans located in the MPO dimerisation zone were found to shape the local glycan processing thereby providing a molecular basis of the site-specific nMPO glycosylation. Native mass spectrometry, mass photometry, and glycopeptide profiling revealed extreme molecular complexity of diprotomeric nMPO arising from heterogeneous glycosylation, oxidation, chlorination and polypeptide truncation variants, and a lower-abundance monomer. Longitudinal profiling of maturing, mature, granule-separated, and pathogen-activated neutrophils demonstrated that MPO is dynamically expressed during granulopoiesis, unevenly distributed across granules and rapidly degranulated, but surprisingly carries uniform glycosylation across conditions. Complete proMPO-to-MPO maturation evidently occur during early/mid-stage granulopoiesis. The conserved Asn355- and Asn391-sequons displayed elevated GlcNAc signatures and higher oxidation and chlorination activity of the secretory vesicle/plasma membrane-resident MPO relative to MPO from other granules. Endoglycosidase H-treated nMPO displaying Asn355-/Asn391-GlcNAcylation recapitulated the activity gain and showed increased thermal stability and polypeptide accessibility relative to untreated nMPO as measured by activity assays, circular dichroism and molecular dynamics. Endoglycosidase H-treated nMPO also demonstrated elevated ceruloplasmin-mediated inhibition relative to nMPO. Modelling revealed that hyper-truncated Asn355-glycans positioned in the MPO:ceruloplasmin interface are critical for uninterrupted inhibition. We report on novel bimodal roles of the peculiar MPO glycosylation providing new insight into neutrophil glycobiology.
Project description:Acute respiratory distress syndrome (ARDS) is a severe critical condition with a high mortality that is currently in focus given that it is associated with mortality caused by coronavirus induced disease 2019 (COVID-19). Neutrophils play a key role in the lung injury characteristic of non-COVID-19 ARDS and there is also accumulating evidence of neutrophil mediated lung injury in patients who succumb to infection with SARS-CoV-2. We undertook a functional proteomic and metabolomic survey of circulating neutrophil populations, comparing patients with COVID-19 ARDS and non-COVID-19 ARDS to understand the molecular basis of neutrophil dysregulation. Expansion of the circulating neutrophil compartment and the presence of activated low and normal density mature and immature neutrophil populations occurs in ARDS, irrespective of cause. Release of neutrophil granule proteins, neutrophil activation of the clotting cascade and upregulation of the Mac-1 platelet binding complex with formation of neutrophil platelet aggregates is exaggerated in COVID-19 ARDS. Importantly, activation of components of the neutrophil type I interferon responses is seen in ARDS following infection with SARS-CoV-2, with associated rewiring of neutrophil metabolism to promote glutamine utilisation, and the upregulation of antigen processing and presentation. Whilst dexamethasone treatment constricts the immature low density neutrophil population it does not impact upon prothrombotic hyperinflammatory neutrophil signatures.
Project description:Coagulation protease factor VIIa (FVIIa) is shown to induce anti-inflammatory and barrier protective effects via endothelial cell protein C receptor (EPCR)-dependent, protease-activated receptor-1 (PAR1)-mediated cell signaling. FVII-EPCR-PAR1 signaling also induces the release of extracellular vesicles from endothelial cells. To obtain clues on whether microRNA (miR) carried out by FVIIa-released EEVs contribute to anti-inflammatory and barrier protective effects, we analyzed miR expression in control- and FVIIa-released EEVs by deep sequencing. These data revealed that several anti-inflammatory miR expression was higher (more than 2-fold) in FVIIa-released EEVs compared to control EEVs, the most predominant being miR10a-5p. The differential expression of miR10a-5p and several other abundant miRs were validated by qRT-PCR. Subsequent in vitro and in vivo experiments showed that miR10a in FVIIa-released EEVs contribute to anti-inflammatory and barrier protective effects.
Project description:More than a century ago Metchnikoff defined neutrophils as small amoeboid-like cells that harbored peculiar polymorphonuclear structures. While since these early studies much has been learned about neutrophil physiology, mechanistic insight into neutrophil polymorphonuclear assembly remains rudimentary. Here we found that depletion of factors, that initiate the loop extrusion program, including NIPBL and MAU2, greatly accelerated the conversion of mononuclear to polymorphonuclear cells and orchestrated the induction of a neutrophil specific transcription signature. Remarkably, mere ablation of either NIPBL or MAU2 expression under conditions that normally prevent neutrophil differentiation, swiftly converted mono-nuclear into polymorphonuclear cells that expressed a neutrophil specific gene program. Depletion of NIPBL and MAU2 in neutrophil progenitors activated an armamentarium of neutrophil-specific enhancers to establish a neutrophil genome depleted for loop extrusion-induced looping. These observations indicate that extinction of the loop extrusion program converts mononuclear progenitor cells into polymorphonuclear cells and suffices to induce a neutrophil specific program of gene expression. Expression profiling by high throughput sequencing
Project description:Our study aims to analyze time-dependent changes in neutrophil phenotype, compare them with included neutrophil-specific mutants, and indentify common signatures among the 5 groups
Project description:More than a century ago Metchnikoff defined neutrophils as small amoeboid-like cells that harbored peculiar polymorphonuclear structures. While since these early studies much has been learned about neutrophil physiology, mechanistic insight into neutrophil polymorphonuclear assembly remains rudimentary. Here we found that depletion of factors, that initiate the loop extrusion program, including NIPBL and MAU2, greatly accelerated the conversion of mononuclear to polymorphonuclear cells and orchestrated the induction of a neutrophil specific transcription signature. Remarkably, mere ablation of either NIPBL or MAU2 expression under conditions that normally prevent neutrophil differentiation, swiftly converted mono-nuclear into polymorphonuclear cells that expressed a neutrophil specific gene program. Depletion of NIPBL and MAU2 in neutrophil progenitors activated an armamentarium of neutrophil-specific enhancers to establish a neutrophil genome depleted for loop extrusion-induced looping. These observations indicate that extinction of the loop extrusion program converts mononuclear progenitor cells into polymorphonuclear cells and suffices to induce a neutrophil specific program of gene expression. Performed gene expression profiling by RNA-seq in progenitors and differentiated neutrophils.