The Experts below are selected from a list of 267708 Experts worldwide ranked by ideXlab platform
Hideoki Ogawa - One of the best experts on this subject based on the ideXlab platform.
-
antimicrobial peptides human β defensins and cathelicidin ll 37 induce the secretion of a pruritogenic cytokine il 31 by human mast cells
Journal of Immunology, 2010Co-Authors: Francois Niyonsaba, Hiroko Ushio, Mutsuko Hara, Hidenori Yokoi, Mitsutoshi Tominaga, Kenji Takamori, Naoki Kajiwara, Hirohisa Saito, Isao Nagaoka, Hideoki OgawaAbstract:In addition to their microbiocidal properties, human beta-defensins (hBDs) and cathelicidin LL-37 stimulate a number of mammalian cell activities, including migration, proliferation, and cytokine/chemokine production. Because hBDs and LL-37 cause mast cells to release pruritogens such as histamine and PGs, we hypothesized that these peptides would stimulate the secretion of a novel pruritogenic mediator IL-31, predominantly produced by T cells. hBDs and LL-37 enhanced IL-31 gene expression and IL-31 protein production and release in the human mast cell line LAD2, as well as in peripheral blood-derived cultured mast cells, suggesting that mast cells are another source of IL-31. Moreover, the expression of IL-31 was elevated in psoriatic skin mast cells, and hBD-2-4 and LL-37, but not hBD-1, enhanced its expression in vivo in rat skin mast cells. hBDs and LL-37 also induced the release of other pruritogenic mediators, including IL-2, IL-4, IL-6, GM-CSF, nerve growth factor, PGE(2), and leukotriene C(4), and increased mRNA expression of substance P. hBD- and LL-37-mediated IL-31 production/release was markedly reduced by pertussis toxin and wortmannin, inhibitors of G-protein and PI3K, respectively. As evidenced by the inhibitory effects of MAPK-specific inhibitors, hBD-2-4 and LL-37 activated the phosphorylation of MAPKs p38, ERK, and JNK that were required for IL-31 production and release. The ability of hBDs and LL-37 to stimulate the production and release of IL-31 by human mast cells provides a novel mechanism by which skin-derived antimicrobial peptides/proteins may contribute to inflammatory reactions and suggests a central role of these peptides in the pathogenesis of skin disorders.
Sarah J Kotecha - One of the best experts on this subject based on the ideXlab platform.
-
effect of late preterm birth on longitudinal lung spirometry in school age children and adolescents
Thorax, 2012Co-Authors: Shantini Paranjothy, John W Watkins, Frank David John Dunstan, John A Henderson, Sarah J KotechaAbstract:Background Rates of preterm birth have increased in most industrialised countries but data on later lung function of late preterm births are limited. A study was undertaken to compare lung function at 8–9 and 14–17 years in children born late preterm (33–34 and 35–36 weeks gestation) with children of similar age born at term (≥37 weeks gestation). Children born at 25–32 weeks gestation were also compared with children born at term. Methods All births from the Avon Longitudinal Study of Parents and Children (n=14 049) who had lung spirometry at 8–9 years of age (n=6705) and/or 14–17 years of age (n=4508) were divided into four gestation groups. Results At 8–9 years of age, all spirometry measures were lower in the 33–34-week gestation group than in controls born at term but were similar to the spirometry decrements observed in the 25–32-week gestation group. The 35–36-week gestation group and term group had similar values. In the late preterm group, at 14–17 years of age forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC) were not significantly different from the term group but FEV 1 /FVC and forced expiratory flow at 25–75% FVC (FEF 25–75% ) remained significantly lower than term controls. Children requiring mechanical ventilation in infancy at 25–32 and 33–34 weeks gestation had in general lower airway function (FEV 1 and FEF 25–75 ) at both ages than those not ventilated in infancy. Conclusions Children born at 33–34 weeks gestation have significantly lower lung function values at 8–9 years of age, similar to decrements observed in the 25–32-week group, although some improvements were noted by 14–17 years of age.
Martin Andersson - One of the best experts on this subject based on the ideXlab platform.
-
Cubosomes for topical delivery of the antimicrobial peptide LL-37.
European Journal of Pharmaceutics and Biopharmaceutics, 2019Co-Authors: Lukas Boge, Lovisa Ringstad, Mina Davoudi, Karin Hallstensson, Jenny Johansson, Therese Andersson, Per Tomas Larsson, Margit Mahlapuu, Joakim Håkansson, Martin AnderssonAbstract:In this study, the use of cubosomes for topical delivery of the antimicrobial peptide (AMP) LL-37 was investigated. Topical delivery of AMPs is of great interest for treatment of skin infections caused by bacteria, such as Staphylococcus aureus. AMP containing cubosomes were produced by three different preparation protocols and compared: (i) pre-loading, where LL-37 was incorporated into a liquid crystalline gel, which thereafter was dispersed into nanoparticles, (ii) post-loading, where LL-37 was let to adsorb onto pre-formed cubosomes, and (iii) hydrotrope-loading, where LL-37 was incorporated during the spontaneously formed cubosomes in an ethanol/glycerol monooleate mixture. Particle size and size distribution were analyzed using dynamic light scattering (DLS), liquid crystalline structure by small angle x-ray scattering (SAXS) and release of LL-37 by a fluorescamine assay. Proteolytic protection of LL-37 as well as bactericidal effect after enzyme exposure was investigated. The skin irritation potential of cubosomes was examined by an in vitro epidermis model. Finally, the bacterial killing property of the cubosomes was examined by an ex vivo pig skin wound infection model with Staphylococcus aureus. Data showed that a high loading of LL-37 induced formation of vesicles in case of cubosomes prepared by sonication (pre-loading). No release of LL-37 was observed from the cubosomes, indicating strong association of the peptide to the particles. Proteolysis studies showed that LL-37 was fully protected against enzymatic attacks while associated with the cubosomes, also denoting strong association of the peptide to the particles. As a consequence, bactericidal effect after enzyme exposure remained, compared to pure LL-37 which was subjected to proteolysis. No skin irritation potential of the cubosomes was found, thus enabling for topical administration. The ex vivo wound infection model showed that LL-37 in pre-loaded cubosomes killed bacteria most efficient.
Kevan L Hartshorn - One of the best experts on this subject based on the ideXlab platform.
-
human defensins and ll 37 in mucosal immunity
Journal of Leukocyte Biology, 2010Co-Authors: Mona Doss, Mitchell R White, Tesfaldet Tecle, Kevan L HartshornAbstract:Defensins are widespread in nature and have activity against a broad range of pathogens. Defensins have direct antimicrobial effects and also modulate innate and adaptive immune responses. We consider the role of human defensins and the cathelicidin LL-37 in defense of respiratory, gastrointestinal, and genitourinary tracts and the oral cavity, skin, and eye. Human beta-defensins (hBDs) and human defensins 5 and 6 (HD5 and -6) are involved most obviously in mucosal responses, as they are produced principally by epithelial cells. Human alpha-defensins 1-4 (or HNPs 1-4) are produced principally by neutrophils recruited to the mucosa. Understanding the biology of defensins and LL-37 is the beginning to clarify the pathophysiology of mucosal inflammatory and infectious diseases (e.g., Crohn's disease, atopic dermatitis, lung or urinary infections). Challenges for these studies are the redundancy of innate defense mechanisms and the presence and interactions of many innate defense proteins in mucosal secretions.
Chrysanthi Paranavitana - One of the best experts on this subject based on the ideXlab platform.
-
the human antimicrobial peptide ll 37 and its fragments possess both antimicrobial and antibiofilm activities against multidrug resistant acinetobacter baumannii
Peptides, 2013Co-Authors: Xiaorong Feng, Karthik Sambanthamoorthy, Thomas J Palys, Chrysanthi ParanavitanaAbstract:Acinetobacter baumannii infections are difficult to treat due to multidrug resistance. Biofilm formation by A. baumannii is an additional factor in its ability to resist antimicrobial therapy. The antibacterial and antibiofilm activities of the human antimicrobial peptide LL-37 and its fragments KS-30, KR-20 and KR-12 against clinical isolates of multidrug-resistant (MDR) A. baumannii were evaluated. The minimal inhibitory concentration (MIC) of LL-37 against MDR A. baumannii isolates ranged from 16 to 32 μg/mL. The MIC of KS-30 fragment varied from 8.0 to 16 μg/mL and the KR-20 fragment MIC ranged from 16 to 64 μg/mL. LL-37 and KS-30 fragment exhibited 100% bactericidal activity against five A. baumannii strains, including four MDR clinical isolates, within 30 min at concentrations of 0.25-1 μg/mL. By 0.5h, the fragments KR-20 and KR-12 eliminated all tested strains at 8 and 64 μg/mL respectively. LL-37 and its fragments displayed anti-adherence activities between 32-128 μg/mL. A minimum biofilm eradication concentration (MBEC) biofilm assay demonstrated that LL-37 inhibited and dispersed A. baumannii biofilms at 32 μg/mL respectively. Truncated fragments of LL-37 inhibited biofilms at concentrations of 64-128 μg/mL. KS-30, the truncated variant of LL-37, effectively dispersed biofilms at 64 μg/mL. At 24h, no detectable toxicity was observed at the efficacious doses when cytotoxicity assays were performed. Thus, LL-37, KS-30 and KR-20 exhibit significant antimicrobial activity against MDR A. baumannii. The prevention of biofilm formation in vitro by LL-37, KS-30 and KR-20 adds significance to their efficacy. These peptides can be potential therapeutics against MDR A. baumannii infections.