| 1. |
- Ali, Mohamad N., et al.
(författare)
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TFPI-2 protects against gram-negative bacterial infection
- 2018
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9:SEP
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Tidskriftsartikel (refereegranskat)abstract
- Tissue factor pathway inhibitor-2 (TFPI-2) has previously been characterized as an endogenous anticoagulant. TFPI-2 is expressed in the vast majority of cells, mainly secreted into the extracellular matrix. Recently we reported that EDC34, a C-terminal peptide derived from TFPI-2, exerts a broad antimicrobial activity. In the present study, we describe a previously unknown antimicrobial mode of action for the human TFPI-2 C-terminal peptide EDC34, mediated via binding to immunoglobulins of the classes IgG, IgA, IgE, and IgM. In particular the interaction of EDC34 with the Fc part of IgG is of importance since this boosts interaction between the immunoglobulin and complement factor C1q. Moreover, we find that the binding increases the C1q engagement of the antigen-antibody interaction, leading to enhanced activation of the classical complement pathway during bacterial infection. In experimental murine models of infection and endotoxin challenge, we show that TFPI-2 is up-regulated in several organs, including the lung. Correspondingly, TFPI-2-/- mice are more susceptible to pulmonary Pseudomonas aeruginosa bacterial infection. No anti-coagulant role of TFPI-2 was observed in these models in vivo. Furthermore, in vivo, the mouse TFPI-2-derived C-terminal peptide VKG24, a homolog to human EDC34 is protective against systemic Escherichia coli bacterial infection. Moreover, in sputum from cystic fibrosis patients TFPI-2 C-terminal fragments are generated and found associated with immunoglobulins. Together our data describe a previously unknown host defense mechanism and therapeutic importance of TFPI-2 against invading Gram-negative bacterial pathogens.
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| 2. |
- Gela, Anele, et al.
(författare)
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Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases
- 2015
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Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 70:2, s. 161-170
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDuring bacterial infections of the airways, a Th1-profiled inflammation promotes the production of several host defense proteins and peptides with antibacterial activities including -defensins, ELR-negative CXC chemokines, and the cathelicidin LL-37. These are downregulated by Th2 cytokines of the allergic response. Instead, the eosinophil-recruiting chemokines eotaxin-1/CCL11, eotaxin-2/CCL24, and eotaxin-3/CCL26 are expressed. This study set out to investigate whether these chemokines could serve as innate host defense molecules during allergic inflammation. MethodsAntibacterial activities of the eotaxins were investigated using viable count assays, electron microscopy, and methods assessing bacterial permeabilization. Fragments generated by mast cell proteases were characterized, and their potential antibacterial, receptor-activating, and lipopolysaccharide-neutralizing activities were investigated. ResultsCCL11, CCL24, and CCL26 all showed potent bactericidal activity, mediated through membrane disruption, against the airway pathogens Streptococcus pneumoniae, Staphylococcus aureus, Nontypeable Haemophilus influenzae, and Pseudomonas aeruginosa. CCL26 retained bactericidal activity in the presence of salt at physiologic concentrations, and the region holding the highest bactericidal activity was the cationic and amphipathic COOH-terminus. Proteolysis of CCL26 by chymase and tryptase, respectively, released distinct fragments of the COOH- and NH2-terminal regions. The COOH-terminal fragment retained antibacterial activity while the NH2-terminal had potent LPS-neutralizing properties in the order of CCL26 full-length protein. An identical fragment to NH2-terminal fragment generated by tryptase was obtained after incubation with supernatants from activated mast cells. None of the fragments activated the CCR3-receptor. ConclusionsTaken together, the findings show that the eotaxins can contribute to host defense against common airway pathogens and that their activities are modulated by mast cell proteases.
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| 3. |
- Gela, Anele, et al.
(författare)
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Midkine in Host Defense.
- 2014
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 171:4, s. 859-869
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Forskningsöversikt (refereegranskat)abstract
- Midkine shares several features in common with antibacterial proteins of the innate immune system. These include growth factor properties, heparin-binding regions, and effects on immune cells (i.e. recruitment and activation of neutrophils and macrophages). Indeed, recent research has demonstrated potent bactericidal and fungicidal activities of midkine. This protein is constitutively expressed at relevant concentrations at barriers of the body, such as in the skin and in the large airways, where the body first encounters potential pathogens. The antibacterial properties of midkine orthologues are preserved during evolution, as exemplified by miple2 of Drosophila. In addition to retinoic acid, gene expression can be promoted by additional factors present at sites of infection, reactive oxygen species, activation of the transcription factor NFκ-B, and hypoxia. In the light of the emerging resistance of pathogenic bacteria to conventional antibiotics, midkine is an interesting molecule that could serve as a template in developing novel pharmaceutical strategies against bacterial and fungal infections, either alone or in combination with conventional antibiotics.
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| 4. |
- Jovic, Sandra, et al.
(författare)
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Expression of MIG/CXCL9 in Cystic Fibrosis and Modulation of Its Activities by Elastase of Pseudomonas aeruginosa.
- 2014
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Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 6:6, s. 846-859
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Tidskriftsartikel (refereegranskat)abstract
- In cystic fibrosis (CF), colonization of the airways with Pseudomonas aeruginosa is associated with disease deterioration. The mechanism behind the disease progression is not fully understood. The present work shows that the antibacterial chemokine MIG/CXCL9 is present in the airways and in sputum of CF patients. MIG/CXCL9 showed high bactericidal activity against. P. aeruginosa, including some strains from the airways of CF patients. Full-length MIG/CXCL9 was detected in sputum from healthy controls and CF patients colonized with P. aeruginosa. However, degraded MIG/CXCL9 was only found in CF sputum. In vitro, elastase of P. aeruginosa cleaved off a fragment of similar size and two additional fragments from MIG/CXCL9. The fragments showed less bactericidal activity against P. aeruginosa compared with the full-length protein. The fragments did not activate the MIG/CXCL9 receptor CXCR3 (expressed e.g. by NK cells, mast cells, and activated T cells) but instead displayed noncompetitive inhibition. In vitro, a decrease in CXCR3-bearing cells was found within and in the proximity of the bronchial epithelium of CF lung tissue compared with controls. Taken together, both bactericidal and cell-recruiting activities of MIG/CXCL9 are corrupted by P. aeruginosa through release of elastase, and this may contribute to impaired airway host defense in CF. © 2014 S. Karger AG, Basel.
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| 5. |
- Jovic, Sandra
(författare)
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On Mechanisms Impairing Airway Host Defence in Cystic Fibrosis
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cystic fibrosis is an inherited disease, caused by mutations of the cystic fibrosis transmembrane conductance regulator gene. The gene codes for a protein that serve as chloride channel. In cystic fibrosis, this protein is lacking or has a defect function resulting in a thick and sticky mucus of the airways. The altered airway environment promotes mucus and growth of pathogenic bacteria. A common pathogen is Pseudomonas aeruginosa that often colonizes the lungs of adult cystic fibrosis patients and is associated with a poor diagnosis. The host defense fails to eradicate the bacteria and instead a prolonged inflammatory response, including excessive recruitment of neutrophils, confers damage to the lungs. To date, several theories exist of why there is an impaired bacterial clearance in the airways of cystic fibrosis patients. Increased salt concentration, reduced depth and pH of the thin fluid lining the epithelial cells are examples. In this thesis, we have examined different mechanisms impairing the host defense in cystic fibrosis. First, we describe that the growth factor midkine is expressed in the airways of cystic fibrosis patients and that it has antibacterial activity against P. aeruginosa. However, both salt and pH alterations reduced the antibacterial activity of midkine. It was also cleaved into smaller fragments by elastases from neutrophils and P. aeruginosa. In a second study, we show that the chemokine MIG/CXCL9 is expressed in the airways of cystic fibrosis patients and that it has antibacterial activity against P. aeruginosa. MIG/CXCL9 was cleaved into three smaller fragments by elastase of P. aeruginosa, that all had reduced antibacterial activity against P. aeruginosa. The degradation also resulted in a reduced recruitment of other immune cells that are involved in eliminating P. aeruginosa. In a third study, we showed that the negatively charged protein, osteopontin is expressed in the airways of cystic fibrosis patients. Interestingly, osteopontin binds to and inhibits the antibacterial activity and receptor activating properties of several ELR-negative CXC chemokines. This is not the case for the neutrophil recruiting ELR-positive CXC chemokines. These interactions can result in an accumulation of neutrophils in the airways and also a reduced antibacterial activity. Lastly, we showed that the neutrophil recruiting chemokine GCP-2/CXCL6 is expressed in the airways of cystic fibrosis patients. GCP-2/CXCL6 binds to free DNA but, its antibacterial activity and receptor activating properties were not affected by this interaction, while the chemotactic properties were slightly decreased. Taken together, this thesis demonstrates several novel mechanisms that explain how the airway immune system is compromised in cystic fibrosis.
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| 6. |
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| 7. |
- Jovic, Sandra, et al.
(författare)
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The neutrophil-recruiting chemokine GCP-2/CXCL6 is expressed in cystic fibrosis airways and retains its functional properties after binding to extracellular DNA.
- 2016
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Ingår i: Mucosal Immunology. - : Elsevier BV. - 1933-0219. ; 9:1, s. 112-123
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Tidskriftsartikel (refereegranskat)abstract
- Infections in cystic fibrosis (CF), often involving Pseudomonas aeruginosa, result from a dysregulated airway immunity where one hallmark is the accumulation of necrotic and apoptotic immune cells, in particular neutrophils. In addition, neutrophils actively release DNA, forming neutrophil extracellular traps (NETs) that contain antimicrobial proteins. Altogether, free DNA in complex with actin accumulates in the airway lumen, resulting in highly viscous sputum that provides an anionic matrix, binding cationic antimicrobial proteins. In this study, granulocyte chemotactic protein 2 (GCP-2)/CXCL6, a neutrophil-activating chemokine with bactericidal properties, was detected in the airway epithelium of CF patients and was also present in azurophilic and specific granules of neutrophils. Elastase of neutrophils, but not of P. aeruginosa, completely degraded CXCL6 (chemokine (C-X-C motif) ligand 6). In addition, CXCL6 colocalized with extracellular DNA in both CF sputa and in in vitro-formed NETs. In vitro, CXCL6 bound DNA with a KD of 2,500 nM. Interestingly, both the bactericidal and the receptor-activating properties of CXCL6 (against neutrophils) remained largely unaffected in the presence of DNA. However, the chemotactic properties of CXCL6 were reduced by the presence of DNA. Taken together, CXCL6 is expressed in CF, retaining its functional properties even after binding to the anionic scaffold that extracellular DNA provides in CF.Mucosal Immunology advance online publication, 20 May 2015; doi:10.1038/mi.2015.43.
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| 8. |
- Marina, Neyssa M., et al.
(författare)
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Comparison of MAPIE versus MAP in patients with a poor response to preoperative chemotherapy for newly diagnosed high-grade osteosarcoma (EURAMOS-1) : an open-label, international, randomised controlled trial
- 2016
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Ingår i: The Lancet Oncology. - 1470-2045. ; 17:10, s. 1396-1408
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Tidskriftsartikel (refereegranskat)abstract
- Background We designed the EURAMOS-1 trial to investigate whether intensified postoperative chemotherapy for patients whose tumour showed a poor response to preoperative chemotherapy (≥10% viable tumour) improved event-free survival in patients with high-grade osteosarcoma. Methods EURAMOS-1 was an open-label, international, phase 3 randomised, controlled trial. Consenting patients with newly diagnosed, resectable, high-grade osteosarcoma aged 40 years or younger were eligible for randomisation. Patients were randomly assigned (1:1) to receive either postoperative cisplatin, doxorubicin, and methotrexate (MAP) or MAP plus ifosfamide and etoposide (MAPIE) using concealed permuted blocks with three stratification factors: trial group; location of tumour (proximal femur or proximal humerus vs other limb vs axial skeleton); and presence of metastases (no vs yes or possible). The MAP regimen consisted of cisplatin 120 mg/m2, doxorubicin 37·5 mg/m2 per day on days 1 and 2 (on weeks 1 and 6) followed 3 weeks later by high-dose methotrexate 12 g/m2 over 4 h. The MAPIE regimen consisted of MAP as a base regimen, with the addition of high-dose ifosfamide (14 g/m2) at 2·8 g/m2 per day with equidose mesna uroprotection, followed by etoposide 100 mg/m2 per day over 1 h on days 1–5. The primary outcome measure was event-free survival measured in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT00134030. Findings Between April 14, 2005, and June 30, 2011, 2260 patients were registered from 325 sites in 17 countries. 618 patients with poor response were randomly assigned; 310 to receive MAP and 308 to receive MAPIE. Median follow-up was 62·1 months (IQR 46·6–76·6); 62·3 months (IQR 46·9–77·1) for the MAP group and 61·1 months (IQR 46·5–75·3) for the MAPIE group. 307 event-free survival events were reported (153 in the MAP group vs 154 in the MAPIE group). 193 deaths were reported (101 in the MAP group vs 92 in the MAPIE group). Event-free survival did not differ between treatment groups (hazard ratio [HR] 0·98 [95% CI 0·78–1·23]); hazards were non-proportional (p=0·0003). The most common grade 3–4 adverse events were neutropenia (268 [89%] patients in MAP vs 268 [90%] in MAPIE), thrombocytopenia (231 [78% in MAP vs 248 [83%] in MAPIE), and febrile neutropenia without documented infection (149 [50%] in MAP vs 217 [73%] in MAPIE). MAPIE was associated with more frequent grade 4 non-haematological toxicity than MAP (35 [12%] of 301 in the MAP group vs 71 [24%] of 298 in the MAPIE group). Two patients died during postoperative therapy, one from infection (although their absolute neutrophil count was normal), which was definitely related to their MAP treatment (specifically doxorubicin and cisplatin), and one from left ventricular systolic dysfunction, which was probably related to MAPIE treatment (specifically doxorubicin). One suspected unexpected serious adverse reaction was reported in the MAP group: bone marrow infarction due to methotrexate. Interpretation EURAMOS-1 results do not support the addition of ifosfamide and etoposide to postoperative chemotherapy in patients with poorly responding osteosarcoma because its administration was associated with increased toxicity without improving event-free survival. The results define standard of care for this population. New strategies are required to improve outcomes in this setting. Funding UK Medical Research Council, National Cancer Institute, European Science Foundation, St Anna Kinderkrebsforschung, Fonds National de la Recherche Scientifique, Fonds voor Wetenschappelijk Onderzoek-Vlaanderen, Parents Organization, Danish Medical Research Council, Academy of Finland, Deutsche Forschungsgemeinschaft, Deutsche Krebshilfe, Federal Ministry of Education and Research, Semmelweis Foundation, ZonMw (Council for Medical Research), Research Council of Norway, Scandinavian Sarcoma Group, Swiss Paediatric Oncology Group, Cancer Research UK, National Institute for Health Research, University College London Hospitals, and Biomedical Research Centre.
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| 9. |
- Nordin, Sara, et al.
(författare)
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High Expression of Midkine in the Airways of Patients with Cystic Fibrosis.
- 2013
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - 1535-4989. ; 49:6, s. 935-942
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in the CFTR gene result in impaired host defense during cystic fibrosis (CF), where Pseudomonas aeruginosa becomes a key pathogen. We investigated the expression pattern of the antibacterial growth factor midkine in CF and possible interference with its activity by the altered airway microenvironment. High midkine expression was found in CF lung tissue compared with controls, involving epithelium of the large and small airways, alveoli, and cells of the submucosa (i.e. neutrophils and mast cells). In CF sputum, midkine was present at 100-fold higher levels but was also subject to increased degradation, compared with midkine in sputum from healthy controls. Midkine had a bactericidal effect on P. aeruginosa but increasing salt concentrations and low pH impaired the activity. Molecular modeling suggested that the effects of salt and pH were due to electrostatic screening and a charge-neutralization of the membrane, respectively. Both neutrophil elastase and elastase of P. aeruginosa cleaved midkine to smaller fragments, resulting in impaired bactericidal activity. Thus, midkine is highly expressed in CF but its bactericidal properties may be impaired by the altered microenvironment as reflected by the in vitro conditions used in this study.
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