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1.	Abdillahi, Suado M., et al. (författare) Collagen VI Contains Multiple Host Defense Peptides with Potent In Vivo Activity 2018 Ingår i: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 201:3, s. 1007-1020 Tidskriftsartikel (refereegranskat)abstract Collagen VI is a ubiquitous extracellular matrix component that forms extensive microfibrillar networks in most connective tissues. In this study, we describe for the first time, to our knowledge, that the collagen VI von Willebrand factor type A like domains exhibit a broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria in human skin infections in vivo. In silico sequence and structural analysis of VWA domains revealed that they contain cationic and amphipathic peptide sequence motifs, which might explain the antimicrobial nature of collagen VI. In vitro and in vivo studies show that these peptides exhibited significant antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa through membrane disruption. Our findings shed new light on the role of collagen VI derived peptides in innate host defense and provide templates for development of peptide-based antibacterial therapies.
2.	Ali, Mohamad N., et al. (författare) TFPI-2 protects against gram-negative bacterial infection 2018 Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9:SEP 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.
3.	Banas, Magdalena, et al. (författare) Chemerin Is an Antimicrobial Agent in Human Epidermis 2013 Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:3 Tidskriftsartikel (refereegranskat)abstract Chemerin, a chemoattractant ligand for chemokine-like receptor 1 (CMKLR1) is predicted to share similar tertiary structure with antibacterial cathelicidins. Recombinant chemerin has antimicrobial activity. Here we show that endogenous chemerin is abundant in human epidermis, and that inhibition of bacteria growth by exudates from organ cultures of primary human skin keratinocytes is largely chemerin-dependent. Using a panel of overlapping chemerin-derived synthetic peptides, we demonstrate that the antibacterial activity of chemerin is primarily mediated by Val 66 -Pro 85, which causes direct bacterial lysis. Therefore, chemerin is an antimicrobial agent in human skin.
4.	Bhongir, Ravi K. V., et al. (författare) DNA-fragmentation is a source of bactericidal activity against Pseudomonas aeruginosa 2017 Ingår i: Biochemical Journal. - 0264-6021. ; 474:3, s. 411-425 Tidskriftsartikel (refereegranskat)abstract Pseudomonas aeruginosa airway infection is common in cystic fibrosis (CF), a disease also characterized by abundant extracellular DNA (eDNA) in the airways. The eDNA is mainly derived from neutrophils accumulating in the airways and contributes to a high sputum viscosity. The altered environment in the lower airways also paves the way for chronic P. aeruginosa infection. Here, we show that mice with P. aeruginosa airway infection have increased survival and decreased bacterial load after topical treatment with DNase. Furthermore, DNA from the sputum of CF patients showed increased bactericidal activity after treatment with DNase ex vivo. Both degraded DNA of neutrophil extracellular traps (NETs) and genomic DNA degraded by serum, acquired bactericidal activity against P. aeruginosa. In vitro, small synthetic DNA-fragments (<100 base pairs) but not large fragments nor genomic DNA, were bactericidal against Gram-negative but not Grampositive bacteria. The addition of divalent cations reduced bacterial killing, suggesting that chelation of divalent cations by DNA results in destabilization of the lipopolysaccharide (LPS) envelope. This is a novel antibacterial strategy where fragmentation of eDNA and DNA-fragments can be used to treat P. aeruginosa airway infection.
5.	Gela, Anele, et al. (författare) Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases 2015 Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 70:2, s. 161-170 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.
6.	Gela, Anele, et al. (författare) Osteopontin binds and modulate functions of eosinophil-recruiting chemokines. 2016 Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 71:1, s. 58-67 Tidskriftsartikel (refereegranskat)abstract Allergic asthma is characterized by eosinophilic inflammation and airway obstruction. There is also an increased risk of pulmonary infection caused by Streptococcus pneumoniae, in particular during severe asthma where high levels of the glycoprotein, osteopontin (OPN) are present in the airways. Eosinophils can be recruited by chemokines activating the receptor CCR3 including eotaxin-1/CCL11, eotaxin-2/CCL24, eotaxin-3/CCL26, RANTES/CCL5, and MEC/CCL28. In addition to inducing chemotaxis, several of these molecules have defensin-like antibacterial properties. This study set out to elucidate the functional consequences of OPN-binding to eosinophil-recruiting chemokines.
7.	Gela, Anele, et al. (författare) Osteopontin That Is Elevated in the Airways during COPD Impairs the Antibacterial Activity of Common Innate Antibiotics. 2016 Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1 Tidskriftsartikel (refereegranskat)abstract Bacterial infections of the respiratory tract contribute to exacerbations and disease progression in chronic obstructive pulmonary disease (COPD). There is also an increased risk of invasive pneumococcal disease in COPD. The underlying mechanisms are not fully understood but include impaired mucociliary clearance and structural remodeling of the airways. In addition, antimicrobial proteins that are constitutively expressed or induced during inflammatory conditions are an important part of the airway innate host defense. In the present study, we show that osteopontin (OPN), a multifunctional glycoprotein that is highly upregulated in the airways of COPD patients co-localizes with several antimicrobial proteins expressed in the airways. In vitro, OPN bound lactoferrin, secretory leukocyte peptidase inhibitor (SLPI), midkine, human beta defensin-3 (hBD-3), and thymic stromal lymphopoietin (TSLP) but showed low or no affinity for lysozyme and LL-37. Binding of OPN impaired the antibacterial activity against the important bacterial pathogens Streptococcus pneumoniae and Pseudomonas aeruginosa. Interestingly, OPN reduced lysozyme-induced killing of S. pneumoniae, a finding that could be explained by binding of OPN to the bacterial surface, thereby shielding the bacteria. A fragment of OPN generated by elastase of P. aeruginosa retained some inhibitory effect. Some antimicrobial proteins have additional functions. However, the muramidase-activity of lysozyme and the protease inhibitory function of SLPI were not affected by OPN. Taken together, OPN can contribute to the impairment of innate host defense by interfering with the function of antimicrobial proteins, thus increasing the vulnerability to acquire infections during COPD.
8.	Kalle, Martina, et al. (författare) A Peptide of Heparin Cofactor II Inhibits Endotoxin-Mediated Shock and Invasive Pseudomonas aeruginosa Infection. 2014 Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:7 Tidskriftsartikel (refereegranskat)abstract Sepsis and septic shock remain important medical problems with high mortality rates. Today's treatment is based mainly on using antibiotics to target the bacteria, without addressing the systemic inflammatory response, which is a major contributor to mortality in sepsis. Therefore, novel treatment options are urgently needed to counteract these complex sepsis pathologies. Heparin cofactor II (HCII) has recently been shown to be protective against Gram-negative infections. The antimicrobial effects were mapped to helices A and D of the molecule. Here we show that KYE28, a 28 amino acid long peptide representing helix D of HCII, is antimicrobial against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungus Candida albicans. Moreover, KYE28 binds to LPS and thereby reduces LPS-induced pro-inflammatory responses by decreasing NF-κB/AP-1 activation in vitro. In mouse models of LPS-induced shock, KYE28 significantly enhanced survival by dampening the pro-inflammatory cytokine response. Finally, in an invasive Pseudomonas infection model, the peptide inhibited bacterial growth and reduced the pro-inflammatory response, which lead to a significant reduction of mortality. In summary, the peptide KYE28, by simultaneously targeting bacteria and LPS-induced pro-inflammatory responses represents a novel therapeutic candidate for invasive infections.
9.	Kalle, Martina, et al. (författare) Host Defense Peptides of Thrombin Modulate Inflammation and Coagulation in Endotoxin-Mediated Shock and Pseudomonas aeruginosa Sepsis. 2012 Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:12 Tidskriftsartikel (refereegranskat)abstract Gram-negative sepsis is accompanied by a disproportionate innate immune response and excessive coagulation mainly induced by endotoxins released from bacteria. Due to rising antibiotic resistance and current lack of other effective treatments there is an urgent need for new therapies. We here present a new treatment concept for sepsis and endotoxin-mediated shock, based on host defense peptides from the C-terminal part of human thrombin, found to have a broad and inhibitory effect on multiple sepsis pathologies. Thus, the peptides abrogate pro-inflammatory cytokine responses to endotoxin in vitro and in vivo. Furthermore, they interfere with coagulation by modulating contact activation and tissue factor-mediated clotting in vitro, leading to normalization of coagulation responses in vivo, a previously unknown function of host defense peptides. In a mouse model of Pseudomonas aeruginosa sepsis, the peptide GKY25, while mediating a modest antimicrobial effect, significantly inhibited the pro-inflammatory response, decreased fibrin deposition and leakage in the lungs, as well as reduced mortality. Taken together, the capacity of such thrombin-derived peptides to simultaneously modulate bacterial levels, pro-inflammatory responses, and coagulation, renders them attractive therapeutic candidates for the treatment of invasive infections and sepsis.
10.	Kalle, Martina, et al. (författare) Proteolytic Activation Transforms Heparin Cofactor II into a Host Defense Molecule 2013 Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 190:12, s. 6303-6310 Tidskriftsartikel (refereegranskat)abstract The abundant serine proteinase inhibitor heparin cofactor II (HCII) has been proposed to inhibit extravascular thrombin. However, the exact physiological role of this plasma protein remains enigmatic. In this study, we demonstrate a previously unknown role for HCII in host defense. Proteolytic cleavage of the molecule induced a conformational change, thereby inducing endotoxin-binding and antimicrobial properties. Analyses employing representative peptide epitopes mapped these effects to helices A and D. Mice deficient in HCII showed increased susceptibility to invasive infection by Pseudomonas aeruginosa, along with a significantly increased cytokine response. Correspondingly, decreased levels of HCII were observed in wild-type animals challenged with bacteria or endotoxin. In humans, proteolytically cleaved HCII forms were detected during wounding and in association with bacteria. Thus, the protease-induced uncovering of cryptic epitopes in HCII, which transforms the molecule into a host defense factor, represents a previously unknown regulatory mechanism in HCII biology and innate immunity.
11.	Kapur, Rick, et al. (författare) Osteopontin mediates murine transfusion-related acute lung injury through stimulation of pulmonary neutrophil accumulation. 2019 Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 134:1, s. 74-84 Tidskriftsartikel (refereegranskat)abstract Transfusion-related acute lung injury (TRALI) is one of the leading causes of transfusion-related fatalities and is characterized by the onset of acute respiratory distress within 6 hours of a blood transfusion. There are no specific therapies available and the pathogenesis remains unclear. Pre-existing inflammation is a risk factor for TRALI and neutrophils (PMNs) are considered to be the major pathogenic cells mediating lung damage. Osteopontin (OPN) is a multifunctional protein expressed at sites of inflammation and, for example, is involved in pulmonary disorders, can regulate cellular migration and can function as a PMN-chemoattractant. We investigated whether OPN is involved in TRALI-induction by promoting PMN-recruitment to the lungs. Using a previously established murine TRALI model, we found that in contrast to wildtype (WT) mice, OPN knock-out (KO) mice were resistant to antibody-mediated PMN-dependent TRALI induction. Administration of purified OPN to the OPN KO mice, however, restored the TRALI response and pulmonary PMN-accumulation. Alternatively, blockade of OPN in WT mice using an anti-OPN antibody prevented the onset of TRALI induction. Using pulmonary immunohistochemistry, OPN could be specifically detected in the lungs of mice that suffered from TRALI. The OPN-mediated TRALI responses were independent from other PMN-chemoattractants including macrophage inflammatory protein (MIP)-2. These data indicate that OPN is critically required for induction of antibody-mediated murine TRALI through localization to the lungs and stimulation of pulmonary PMN-recruitment. This suggests that anti-OPN antibody-therapy may be a potential strategy to explore in targeting TRALI in patients.
12.	Kasetty, Gopinath, et al. (författare) Anti-endotoxic and antibacterial effects of a dermal substitute coated with host defense peptides. 2015 Ingår i: Biomaterials. - : Elsevier BV. - 1878-5905 .- 0142-9612. ; 53, s. 415-425 Tidskriftsartikel (refereegranskat)abstract Biomaterials used during surgery and wound treatment are of increasing importance in modern medical care. In the present study we set out to evaluate the addition of thrombin-derived host defense peptides to human acellular dermis (hAD, i.e. epiflex(®)). Antimicrobial activity of the functionalized hAD was demonstrated using radial diffusion and viable count assays against Gram-negative Escherichia coli, Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus bacteria. Electron microscopy analyses showed that peptide-mediated bacterial killing led to reduced hAD degradation. Furthermore, peptide-functionalized hAD displayed endotoxin-binding activity in vitro, as evidenced by inhibition of NF-κB activation in human monocytic cells (THP-1 cells) and a reduction of pro-inflammatory cytokine production in whole blood in response to lipopolysaccharide stimulation. The dermal substitute retained its anti-endotoxic activity after washing, compatible with results showing that the hAD bound a significant amount of peptide. Furthermore, bacteria-induced contact activation was inhibited by peptide addition to the hAD. E. coli infected hAD, alone, or after treatment with the antiseptic substance polyhexamethylenebiguanide (PHMB), yielded NF-κB activation in THP-1 cells. The activation was abrogated by peptide addition. Thus, thrombin-derived HDPs should be of interest in the further development of new biomaterials with combined antimicrobial and anti-endotoxic functions for use in surgery and wound treatment.
13.	Kasetty, Gopinath (författare) HOST DEFENSE PEPTIDES OF THE COAGULATION SYSTEM AND THEIR THERAPEUTIC POTENTIAL 2014 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Prevention and control of infectious diseases is seriously hampered by an increasing prevalence of bacteria that are resistant towards conventional antibiotics. Resistant bacteria are often the root cause of infections that trigger the complex clinical syndrome called sepsis, which is a concern for high morbidity and mortality. Despite extensive basic research and clinical studies, treatment of sepsis remains challenging due to an uncontrolled immune response mediated by various phagocytic cells, and the coagulation and complement cascades. Emerging evidence suggests that host defense peptides (HDPs) may be potential lead structures in sepsis treatment due to their ability to modulate innate immune responses as well as being directly antimicrobial. From that perspective, this thesis aimed to identify and characterize the structure-activity relationships of small HDPs derived from serine proteases. In paper I and II, structural features, governing the antimicrobial activity of peptides derived from the C-terminal region of human serine proteases were identified. Moreover the potential of these peptides to modulate inflammatory responses caused by bacterial lipopolysaccharide (LPS) was investigated. Truncated forms of thrombin-derived C-terminal peptides exhibited length- and sequence-dependent antimicrobial and immunomodulating effects in vitro and in vivo as illustrated by increasing survival rates in mouse models of LPS-induced septic shock (paper I). Quantitative structure-activity relationship (QSAR) analysis utilizing biophysical, antimicrobial and immunomodulatory activities of peptides derived from evolutionary conserved C-terminal protease domains of serine proteases, disclosed a set of active peptides with potent selective membrane disrupting effects and promising therapeutic potential in animal models of LPS-induced septic shock (paper II). The data in Paper III demonstrate generation of antimicrobial peptides from the C-terminal region of the human coagulation factor X by proteolytic cleavage with human leukocyte elastase as well as P. aeruginosa elastase. The prototypic peptide RKG25 derived from the core region of the FX protease domain, exhibited multiple biological functions including, antimicrobial, anti-inflammatory and anticoagulant effects. In summary, the findings of multiple immunomodulatory functions of these novel HDPs provides a possible new approach for the development of treatments for bacterial infections.
14.	Kasetty, Gopinath, et al. (författare) Osteopontin protects against lung injury caused by extracellular histones 2019 Ingår i: Mucosal Immunology. - : Elsevier BV. - 1933-0219 .- 1935-3456. ; 12:1, s. 39-50 Tidskriftsartikel (refereegranskat)abstract Extracellular histones are present in the airways because of cell death occurring during inflammation. They promote inflammation and cause tissue damage due to their cationic nature. The anionic phosphoglycoprotein osteopontin (OPN) is expressed at high levels during airway inflammation and has been ascribed both pro- and anti-inflammatory roles. In this study, it was hypothesized that OPN may neutralize the harmful activities of extracellular histones at the airway mucosal surface. In a model of histone-induced acute lung injury, OPN−/− mice showed increased inflammation and tissue injury, and succumbed within 24 h, whereas wild-type mice showed lower degrees of inflammation and no mortality. In lipopolysaccharide-induced acute lung injury, wild-type mice showed less inflammation and tissue injury than OPN−/− mice. In bronchoalveolar lavage fluid from ARDS patients, high levels of OPN and also histone–OPN complexes were detected. In addition, OPN bound to histones with high affinity in vitro, resulting in less cytotoxicity and reduced formation of tissue-damaging neutrophil extracellular traps (NETs). The interaction between OPN and histones was dependent on posttranslational modification of OPN, i.e., phosphorylation. The findings demonstrate a novel role for OPN, modulating the pro-inflammatory and cytotoxic properties of free histones.
15.	Kasetty, Gopinath, et al. (författare) Osteopontin protects against pneumococcal infection in a murine model of allergic airway inflammation 2019 Ingår i: Allergy: European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538. ; 74:4, s. 663-674 Tidskriftsartikel (refereegranskat)abstract Background: In atopic asthma, chronic Th2-biased inflammation is associated with an increased risk of pneumococcal infection. The anionic phosphoglycoprotein osteopontin (OPN) is highly expressed in asthma and has been ascribed several roles during inflammation. This study aimed to investigate whether OPN affects inflammation and vulnerability to pneumococcal infection in atopic asthma. Methods: House dust mite (HDM) extract was used to induce allergic airway inflammation in both wild-type (Spp1+/+) and OPN knockout (Spp1−/−) C57BL/6J mice, and the airway was then infected with Streptococcus pneumoniae. Parameters reflecting inflammation, tissue injury, and bacterial burden were measured. In addition, samples from humans with allergic asthma were analyzed. Results: Both allergen challenge in individuals with allergic asthma and the intranasal instillation of HDM in mice resulted in increased OPN levels in bronchoalveolar lavage fluid (BALF). More immune cells (including alveolar macrophages, neutrophils, eosinophils, and lymphocytes) and higher levels of proinflammatory cytokines were found in Spp1−/− mice than in Spp1+/+ mice. Moreover, OPN-deficient mice exhibited increased levels of markers reflecting tissue injury. Upon infection with S. pneumoniae, Spp1+/+ mice with allergic airway inflammation had a significantly lower bacterial burden in both BALF and lung tissue than did Spp1−/− mice. Furthermore, Spp1−/− mice had higher levels of cytokines and immune cells in BALF than did Spp1+/+ mice. Conclusion: OPN reduces inflammation, decreases tissue injury, and reduces bacterial loads during concurrent pneumococcal infection and allergic airway inflammation in a murine model. These findings suggest that OPN significantly affects vulnerability to pneumococcal infection in atopic asthma.
16.	Kasetty, Gopinath, et al. (författare) Roflumilast increases bacterial load and dissemination in a model of Pseudomononas aeruginosa airway infection 2016 Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103. ; 357:1, s. 66-72 Tidskriftsartikel (refereegranskat)abstract Exacerbations present a major clinical problem in many patients suffering from COPD. Roflumilast, an inhibitor of phosphodiesterase 4, has beneficial effects in several clinical trials and is currently widely used to prevent exacerbations in severe COPD. Roflumilast has anti-inflammatory properties that may interfere with potentially important host defense functions, including cytotoxic properties of neutrophils at sites of inflammation. Since chronic bacterial infection are prevalent in severe COPD, Pseudomonas aeruginosa being a major pathogen, we hypothesized that this drug could impair host defense against P. aeruginosa. In this study, mice were pretreated with vehicle alone or roflumilast at doses of 5 mg/kg or 10 mg/kg followed by instillation of P. aeruginosa in the airways. Bacterial load and dissemination as well as inflammatory markers and immune cells present in the airways were followed. Roflumilast increased mortality, bacterial load and dissemination in mice infected with P. aeruginosa. In addition, roflumilast-treated mice had significantly lower number of neutrophils in the bronchi but not in the lung tissue airways compared with untreated mice. Several proinflammatory cytokines decreased in roflumilast-treated mice but neither the neutrophil-recruiting chemokine KC nor IL-6. The findings show that roflumilast-treatment impair host defense against P. aeruginosa in the airways. This may imply that patients suffering from chronic bacterial infection of the airways could benefit from being withheld treatment with roflumilast.
17.	Kasetty, Gopinath, et al. (författare) Structure-Activity Studies and Therapeutic Potential of Host Defense Peptides of Human Thrombin 2011 Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 55:6, s. 2880-2890 Tidskriftsartikel (refereegranskat)abstract Peptides of the C-terminal region of human thrombin are released upon proteolysis and identified in human wounds. In this study, we wanted to investigate minimal determinants, as well as structural features, governing the antimicrobial and immunomodulating activity of this peptide region. Sequential amino acid deletions of the peptide GKYGFYTHVFRLKKWIQKVIDQFGE (GKY25), as well as substitutions at strategic and structurally relevant positions, were followed by analyses of antimicrobial activity against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive bacterium Staphylococcus aureus, and the fungus Candida albicans. Furthermore, peptide effects on lipopolysaccharide (LPS)-, lipoteichoic acid-, or zymosan-induced macrophage activation were studied. The thrombin-derived peptides displayed length-and sequence-dependent antimicrobial as well as immunomodulating effects. A peptide length of at least 20 amino acids was required for effective anti-inflammatory effects in macrophage models, as well as optimal antimicrobial activity as judged by MIC assays. However, shorter (> 12 amino acids) variants also displayed significant antimicrobial effects. A central K14 residue was important for optimal antimicrobial activity. Finally, one peptide variant, GKYGFYTHVFRLKKWIQKVI (GKY20) exhibiting improved selectivity, i.e., low toxicity and a preserved antimicrobial as well as anti-inflammatory effect, showed efficiency in mouse models of LPS shock and P. aeruginosa sepsis. The work defines structure-activity relationships of C-terminal host defense peptides of thrombin and delineates a strategy for selecting peptide epitopes of therapeutic interest.
18.	Kasetty, Gopinath, et al. (författare) The C-Terminal Sequence of Several Human Serine Proteases Encodes Host Defense Functions. 2011 Ingår i: Journal of Innate Immunity. - : S. Karger AG. - 1662-811X .- 1662-8128. ; 3:5, s. 471-482 Tidskriftsartikel (refereegranskat)abstract Serine proteases of the S1 family have maintained a common structure over an evolutionary span of more than one billion years, and evolved a variety of substrate specificities and diverse biological roles, involving digestion and degradation, blood clotting, fibrinolysis and epithelial homeostasis. We here show that a wide range of C-terminal peptide sequences of serine proteases, particularly from the coagulation and kallikrein systems, share characteristics common with classical antimicrobial peptides of innate immunity. Under physiological conditions, these peptides exert antimicrobial effects as well as immunomodulatory functions by inhibiting macrophage responses to bacterial lipopolysaccharide. In mice, selected peptides are protective against lipopolysaccharide-induced shock. Moreover, these S1-derived host defense peptides exhibit helical structures upon binding to lipopolysaccharide and also permeabilize liposomes. The results uncover new and fundamental aspects on host defense functions of serine proteases present particularly in blood and epithelia, and provide tools for the identification of host defense molecules of therapeutic interest.
19.	Kasetty, Gopinath, et al. (författare) The nonantibiotic macrolide em703 improves survival in a model of quinolone-treated pseudomonas aeruginosa airway infection 2017 Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804. ; 61:9 Tidskriftsartikel (refereegranskat)abstract Macrolide antibiotics are used as anti-inflammatory agents, e.g., for prevention of exacerbations in chronic obstructive pulmonary disease and cystic fibrosis. Several studies have shown improved outcomes after the addition of macrolides to -lactam antibiotics for treatment of severe community-acquired pneumonia. However, a beneficial effect of macrolides in treating Gram-negative bacterial airway infections, e.g., those caused by Pseudomonas aeruginosa, remains to be shown. Macrolide antibiotics have significant side effects, in particular, motility-stimulating activity in the gastrointestinal tract and promotion of bacterial resistance. In this study, EM703, a modified macrolide lacking antibiotic and motility-stimulating activities but with retained anti-inflammatory properties, was used as an adjunct treatment for experimental P. aeruginosa lung infection, in combination with a conventional antibiotic. Airway infections in BALB/cJRj mice were induced by nasal instillation of P. aeruginosa; this was followed by treatment with the quinolone levofloxacin in the absence or presence of EM703. Survival, inflammatory responses, and cellular influx to the airways were monitored. Both pretreatment and simultaneous administration of EM703 dramatically improved survival in levofloxacin-treated mice with P. aeruginosa airway infections. In addition, EM703 reduced the levels of proinflammatory cytokines, increased the numbers of leukocytes in bronchoalveolar lavage fluid, and reduced the numbers of neutrophils present in lung tissue. In summary, the findings of this study show that the immunomodulatory properties of the modified macrolide EM703 can be important when treating Gram-negative pneumonia, as exemplified by P. aeruginosa infection in this study.
20.	Kasetty, Gopinath, et al. (författare) Vertebrate TFPI-2 C-terminal peptides exert therapeutic applications against Gram-negative infections 2016 Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 16:1 Tidskriftsartikel (refereegranskat)abstract Background: Tissue factor pathway inhibitor-2 (TFPI-2) is a serine protease inhibitor that exerts multiple physiological and patho-physiological activities involving the modulation of coagulation, angiogenesis, tumor invasion, and apoptosis. In previous studies we reported a novel role of human TFPI-2 in innate immunity by serving as a precursor for host defense peptides. Here we employed a number of TFPI-2 derived peptides from different vertebrate species and found that their antibacterial activity is evolutionary conserved although the amino acid sequence is not well conserved. We further studied the theraputic potential of one selected TFPI-2 derived peptide (mouse) in a murine sepsis model. Results: Hydrophobicity and net charge of many peptides play a important role in their host defence to invading bacterial pathogens. In vertebrates, the C-terminal portion of TFPI-2 consists of a highly conserved cluster of positively charged amino acids which may point to an antimicrobial activity. Thus a number of selected C-terminal TFPI-2 derived peptides from different species were synthesized and it was found that all of them exert antimicrobial activity against E. coli and P. aeruginosa. The peptide-mediated killing of E. coli was enhanced in human plasma, suggesting an involvement of the classical pathway of the complement. Under in vitro conditions the peptides displayed anti-coagulant activity by modulating the intrinsic pathway of coagulation and in vivo treatment with the mouse derived VKG24 peptide protects mice from an otherwise lethal LPS shock model. Conclusions: Our results suggest that the evolutionary conserved C-terminal part of TFPI-2 is an interesting agent for the development of novel antimicrobial therapies.
21.	Malmsten, Martin, et al. (författare) Highly Selective End-Tagged Antimicrobial Peptides Derived from PRELP 2011 Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:1, s. e16400- Tidskriftsartikel (refereegranskat)abstract Background: Antimicrobial peptides (AMPs) are receiving increasing attention due to resistance development against conventional antibiotics. Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in an array of infections such as ocular infections, cystic fibrosis, wound and post-surgery infections, and sepsis. The goal of the study was to design novel AMPs against these pathogens. Methodology and Principal Findings: Antibacterial activity was determined by radial diffusion, viable count, and minimal inhibitory concentration assays, while toxicity was evaluated by hemolysis and effects on human epithelial cells. Liposome and fluorescence studies provided mechanistic information. Protease sensitivity was evaluated after subjection to human leukocyte elastase, staphylococcal aureolysin and V8 proteinase, as well as P. aeruginosa elastase. Highly active peptides were evaluated in ex vivo skin infection models. C-terminal end-tagging by W and F amino acid residues increased antimicrobial potency of the peptide sequences GRRPRPRPRP and RRPRPRPRP, derived from proline arginine-rich and leucine-rich repeat protein (PRELP). The optimized peptides were antimicrobial against a range of Gram-positive S. aureus and Gram-negative P. aeruginosa clinical isolates, also in the presence of human plasma and blood. Simultaneously, they showed low toxicity against mammalian cells. Particularly W-tagged peptides displayed stability against P. aeruginosa elastase, and S. aureus V8 proteinase and aureolysin, and the peptide RRPRPRPRPWWWW-NH2 was effective against various "superbugs'' including vancomycin-resistant enterococci, multi-drug resistant P. aeruginosa, and methicillin-resistant S. aureus, as well as demonstrated efficiency in an ex vivo skin wound model of S. aureus and P. aeruginosa infection. Conclusions/Significance: Hydrophobic C-terminal end-tagging of the cationic sequence RRPRPRPRP generates highly selective AMPs with potent activity against multiresistant bacteria and efficiency in ex vivo wound infection models. A precise "tuning'' of toxicity and proteolytic stability may be achieved by changing tag-length and adding W-or F-amino acid tags.
22.	Papareddy, Praveen, et al. (författare) A human antithrombin isoform dampens inflammatory responses and protects from organ damage during bacterial infection 2019 Ingår i: Nature Microbiology. - : Springer Science and Business Media LLC. - 2058-5276. ; 4:12, s. 2442-2455 Tidskriftsartikel (refereegranskat)abstract Severe infectious diseases are often characterized by an overwhelming and unbalanced systemic immune response to microbial infections. Human antithrombin (hAT) is a crucial coagulation inhibitor with anti-inflammatory activities. Here we identify three hAT-binding proteins (CD13, CD300f and LRP-1) on human monocytes that are involved in blocking the activity of nuclear factor-kappa B. We found that the modulating effect is primarily restricted to the less abundant beta-isoform (h beta AT) of hAT that lacks N-glycosylation at position 135. Individuals with a mutation at this position have increased production of h beta AT and analysis of their blood, which was stimulated ex vivo with lipopolysaccharide, showed a decreased inflammatory response. Similar findings were recorded when heterozygotic mice expressing hAT or h beta AT were challenged with lipopolysaccharide or infected with Escherichia coli bacteria. Our results finally demonstrate that in a lethal E. coli infection model, survival rates increased when mice were treated with h beta AT one hour and five hours after infection. The treatment also resulted in a reduction of the inflammatory response and less severe organ damage.
23.	Papareddy, Praveen, et al. (författare) An ecoimmunological approach to study evolutionary and ancient links between coagulation, complement and Innate immunity 2018 Ingår i: Virulence. - : Informa UK Limited. - 2150-5608 .- 2150-5594. ; 9:1, s. 724-737 Tidskriftsartikel (refereegranskat)abstract Coagulation, complement, and innate immunity are tightly interwoven and form an alliance that can be traced back to early eukaryotic evolution. Here we employed an ecoimmunological approach using Tissue Factor Pathway Inhibitor (TFPI)-1-derived peptides from the different classes of vertebrates (i.e. fish, reptile, bird, and mammals) and tested whether they can boost killing of various human bacterial pathogens in plasma. We found signs of species-specific conservation and diversification during evolution in these peptides that significantly impact their antibacterial activity. Though all peptides tested executed bactericidal activity in mammalian plasma (with the exception of rodents), no killing was observed in plasma from birds, reptiles, and fish, pointing to a crucial role for the classical pathway of the complement system. We also observed an interference of these peptides with the human intrinsic pathway of coagulation though, unlike complement activation, this mechanism appears not to be evolutionary conserved.
24.	Papareddy, Praveen, et al. (författare) C-terminal Peptides of Tissue Factor Pathway Inhibitor Are Novel Host Defense Molecules 2010 Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:36, s. 28387-28398 Tidskriftsartikel (refereegranskat)abstract Tissue factor pathway inhibitor (TFPI) inhibits tissue factor-induced coagulation, but may, via its C terminus, also modulate cell surface, heparin, and lipopolysaccharide interactions as well as participate in growth inhibition. Here we show that C-terminal TFPI peptide sequences are antimicrobial against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, Gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungi Candida albicans and Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen for the "classic" human antimicrobial peptide LL-37. The killing of E. coli, but not P. aeruginosa, by the C-terminal peptide GGLIKTKRKRKKQRVKIAYEEIFVKNM (GGL27), was enhanced in human plasma and largely abolished in heat-inactivated plasma, a phenomenon linked to generation of antimicrobial C3a and activation of the classic pathway of complement activation. Furthermore, GGL27 displayed anti-endotoxic effects in vitro and in vivo in a mouse model of LPS shock. Importantly, TFPI was found to be expressed in the basal layers of normal epidermis, and was markedly up-regulated in acute skin wounds as well as wound edges of chronic leg ulcers. Furthermore, C-terminal fragments of TFPI were associated with bacteria present in human chronic leg ulcers. These findings suggest a new role for TFPI in cutaneous defense against infections.
25.	Papareddy, Praveen, et al. (författare) NLF20: an antimicrobial peptide with therapeutic potential against invasive Pseudomonas aeruginosa infection. 2016 Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 1460-2091 .- 0305-7453. ; 71:1, s. 170-180 Tidskriftsartikel (refereegranskat)abstract Increasing resistance to antibiotics makes antimicrobial peptides interesting as novel therapeutics. Here, we report on studies of the peptide NLF20 (NLFRKLTHRLFRRNFGYTLR), corresponding to an epitope of the D helix of heparin cofactor II (HCII), a plasma protein mediating bacterial clearance.

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