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Статті в журналах з теми "LL-37 peptid":

1

Guo, Fang-Fang, and Jing-Yuan Fang. "Antimicrobial peptide LL-37 and gastrointestinal diseases." World Chinese Journal of Digestology 22, no. 35 (2014): 5454. http://dx.doi.org/10.11569/wcjd.v22.i35.5454.

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2

Bucki, Robert, Katarzyna Leszczyńska, Andrzej Namiot, and Wojciech Sokołowski. "Cathelicidin LL-37: A Multitask Antimicrobial Peptide." Archivum Immunologiae et Therapiae Experimentalis 58, no. 1 (January 5, 2010): 15–25. http://dx.doi.org/10.1007/s00005-009-0057-2.

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3

Rapala-Kozik, Maria, Oliwia Bochenska, Marcin Zawrotniak, Natalia Wolak, Grzegorz Trebacz, Mariusz Gogol, Dominika Ostrowska, Wataru Aoki, Mitsuyoshi Ueda, and Andrzej Kozik. "Inactivation of the Antifungal and Immunomodulatory Properties of Human Cathelicidin LL-37 by Aspartic Proteases Produced by the Pathogenic Yeast Candida albicans." Infection and Immunity 83, no. 6 (April 6, 2015): 2518–30. http://dx.doi.org/10.1128/iai.00023-15.

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Constant cross talk betweenCandida albicansyeast cells and their human host determines the outcome of fungal colonization and, eventually, the progress of infectious disease (candidiasis). An effective weapon used byC. albicansto cope with the host defense system is the release of 10 distinct secreted aspartic proteases (SAPs). Here, we validate a hypothesis that neutrophils and epithelial cells use the antimicrobial peptide LL-37 to inactivateC. albicansat sites of candidal infection and thatC. albicansuses SAPs to effectively degrade LL-37. LL-37 is cleaved into multiple products by SAP1 to -4, SAP8, and SAP9, and this proteolytic processing is correlated with the gradual decrease in the antifungal activity of LL-37. Moreover, a major intermediate of LL-37 cleavage—the LL-25 peptide—is antifungal but devoid of the immunomodulatory properties of LL-37. In contrast to LL-37, LL-25 did not affect the generation of reactive oxygen species by neutrophils upon treatment with phorbol esters. Stimulating neutrophils with LL-25 (rather than LL-37) significantly decreased calcium flux and interleukin-8 production, resulting in lower chemotactic activity of the peptide against neutrophils, which may decrease the recruitment of neutrophils to infection foci. LL-25 also lost the function of LL-37 as an inhibitor of neutrophil apoptosis, thereby reducing the life span of these defense cells. This study indicates thatC. albicanscan effectively use aspartic proteases to destroy the antimicrobial and immunomodulatory properties of LL-37, thus enabling the pathogen to survive and propagate.
4

Sieprawska-Lupa, Magdalena, Piotr Mydel, Katarzyna Krawczyk, Kinga Wójcik, Magdalena Puklo, Boguslaw Lupa, Piotr Suder, et al. "Degradation of Human Antimicrobial Peptide LL-37 by Staphylococcus aureus-Derived Proteinases." Antimicrobial Agents and Chemotherapy 48, no. 12 (December 2004): 4673–79. http://dx.doi.org/10.1128/aac.48.12.4673-4679.2004.

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ABSTRACT Cathelicidin LL-37 is one of the few human bactericidal peptides with potent antistaphylococcal activity. In this study we examined the susceptibility of LL-37 to proteolytic degradation by two major proteinases produced by Staphylococcus aureus, a metalloproteinase (aureolysin) and a glutamylendopeptidase (V8 protease). We found that aureolysin cleaved and inactivated LL-37 in a time- and concentration-dependent manner. Analysis of the generated fragments by mass spectroscopy revealed that the initial cleavage of LL-37 by aureolysin occurred between the Arg19-Ile20, Arg23-Ile24, and Leu31-Val32 peptide bonds, instantly annihilating the antibacterial activity of LL-37. In contrast, the V8 proteinase hydrolyzed efficiently only the Glu16-Phe17 peptide bond, rendering the C-terminal fragment refractory to further degradation. This fragment (termed LL-17-37) displayed antibacterial activity against S. aureus at a molar level similar to that of the full-length LL-37 peptide, indicating that the antibacterial activity of LL-37 resides in the C-terminal region. In keeping with LL-37 degradation by aureolysin, S. aureus strains that produce significant amounts of this metalloprotease were found to be less susceptible to LL-17-37 than strains expressing no aureolysin activity. Taken together, these data suggest that aureolysin production by S. aureus contributes to the resistance of this pathogen to the innate immune system of humans mediated by LL-37.
5

Martynowycz, Michael, Amy Rice, Konstantin Andreev, Thatyane M. Nobre Pavinatto, Jeff Wereszczynski, and David Gidalevitz. "Interaction of Antimicrobial Peptide Ll-37 with Lipopolysaccharides." Biophysical Journal 116, no. 3 (February 2019): 45a. http://dx.doi.org/10.1016/j.bpj.2018.11.285.

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6

Yusuf, Muhammad, Wanda Destiarani, Ade Rizqi Ridwan Firdaus, Fauzian Giansyah Rohmatulloh, Mia Tria Novianti, Gita Widya Pradini, and Reiva Farah Dwiyana. "Residual Interactions of LL-37 with POPC and POPE:POPG Bilayer Model Studied by All-Atom Molecular Dynamics Simulation." International Journal of Molecular Sciences 23, no. 21 (November 2, 2022): 13413. http://dx.doi.org/10.3390/ijms232113413.

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LL-37 is a membrane-active antimicrobial peptide (AMP) that could disrupt the integrity of bacterial membranes due to its inherent cationic and amphipathic nature. Developing a shorter derivative of a long peptide such as LL-37 is of great interest, as it can reduce production costs and cytotoxicity. However, more detailed information about the residual interaction between LL-37 and the membrane is required for further optimization. Previously, molecular dynamics simulation using mixed all-atom and united-atom force fields showed that LL-37 could penetrate the bilayer membrane. This study aimed to perform all-atom molecular dynamics simulations, highlighting the residual interaction of LL-37 with the simplest model of the bacterial membrane, POPE:POPG (2:1), and compare its interaction with the POPC, which represents the eukaryotic membrane. The result showed leucine–leucine as the leading residues of LL-37 that first contact the membrane surface. Then, the cationic peptide of LL-37 started to penetrate the membrane by developing salt bridges between positively charged amino acids, Lys–Arg, and the exposed phosphate group of POPE:POPG, which is shielded in POPC. Residues 18 to 29 are suggested as the core region of LL-37, as they actively interact with the POPE:POPG membrane, not POPC. These results could provide a basis for modifying the amino acid sequence of LL-37 and developing a more efficient design for LL-37 derivatives.
7

Zhao, Chengquan, Tung Nguyen, Lee Ming Boo, Teresa Hong, Cesar Espiritu, Dmitri Orlov, Wei Wang, Alan Waring, and Robert I. Lehrer. "RL-37, an Alpha-Helical Antimicrobial Peptide of the Rhesus Monkey." Antimicrobial Agents and Chemotherapy 45, no. 10 (October 1, 2001): 2695–702. http://dx.doi.org/10.1128/aac.45.10.2695-2702.2001.

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ABSTRACT Rhesus monkey bone marrow expresses a cathelicidin whose C-terminal domain comprises a 37-residue alpha-helical peptide (RL-37) that resembles human LL-37. Like its human counterpart, RL-37 rapidly permeabilized the membranes of Escherichia coli ML-35p and lysed liposomes that simulated bacterial membranes. When tested in media whose NaCl concentrations approximated those of extracellular fluids, RL-37 was considerably more active than LL-37 against staphylococci. Whereas human LL-37 contains five acidic residues and has a net charge of +6, rhesus RL-37 has only two acidic residues and a net charge of +8. Speculating that the multiple acidic residues of human LL-37 reduced its efficacy against staphylococci, we made a peptide (LL-37 pentamide) in which each aspartic acid of LL-37 was replaced by an asparagine and each glutamic acid was replaced by a glutamine. LL-37 pentamide's antistaphylococcal activity was substantially greater than that of LL-37. Thus, although the precursor of LL-37 is induced in human skin keratinocytes by injury or inflammation, its insufficiently cationic antimicrobial domain may contribute to the success of staphylococci in colonizing and infecting human skin.
8

Bals, Robert, Xiaorong Wang, Michael Zasloff, and James M. Wilson. "The peptide antibiotic LL-37/hCAP-18 is expressed in epithelia of the human lung where it has broad antimicrobial activity at the airway surface." Proceedings of the National Academy of Sciences 95, no. 16 (August 4, 1998): 9541–46. http://dx.doi.org/10.1073/pnas.95.16.9541.

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The airway surface is an important host defense against pulmonary infection. Secretion of proteins with antimicrobial activity from epithelial cells onto the airway surface represents an important component of this innate immune system. Defensins are the best characterized epithelial-derived peptide antibiotics. A member of another family of peptide antibiotics called cathelicidins recently was identified from human bone marrow. We show in this paper that this human peptide named LL-37/hCAP-18 also may play a role in innate immunity of the human lung.In situhybridization localized high levels of LL-37/hCAP-18 RNA to surface epithelial cells of the conducting airway as well as serous and mucous cells of the submucosal glands. LL-37/hCAP-18 peptide with antimicrobial activity was partially purified from airway surface fluid from human lung and a human bronchial xenograft model. The synthetic peptide LL-37 demonstrated antibiotic activity against a number of Gram-negative and Gram-positive organisms includingPseudomonas aeruginosa; bacterial killing of LL-37 was sensitive to NaCl and was synergistic with lactoferrin and lysozyme. In summary, we show that LL-37/hCAP-18 is a peptide with broad antimicrobial activity that is secreted onto the airway surface from epithelial cells of the human lung.
9

Ishvaanjil, Bayartbat, Yu-Jin Jung, Uyangaa Temuujin, Soon-Youl Lee, and Kwon-Kyoo Kang. "HETEROLOGOUS EXPRESSION OF ANTIMICROBIAL PEPTIDE LL-37 IN CHINESE CABBAGE WITH ENHANCED RESISTANCE TO PATHOGENS." Mongolian Journal of Agricultural Sciences 13, no. 2 (June 22, 2015): 124–30. http://dx.doi.org/10.5564/mjas.v13i2.531.

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The human antimicrobial peptide, LL-37 gene was overexpressed in Chinese cabbage ‘Osome’ (Brassica rapa) by Agrobacterium tumefaciens-mediated transformation. In order to increase the expression of the antimicrobial peptide, we used RolA intron sequence in front of the LL-37peptide gene. We confirmed the expression of LL-37 in cabbage by RT-PCR and Western Blot analysis. Four transgenic T1 plants were confirmed that LL-37 was expressed. Cabbages expressing the humanLL-37 gene were challenged by various plant pathogen. Transgenic cabbage plants overproducing human LL-37 are expected to possess a durable and wide-spectrum resistance against various pathogens.Mongolian Journal of Agricultural Sciences Vol.13(2) 2014: 124-130
10

Ridyard, Kylen E., and Joerg Overhage. "The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent." Antibiotics 10, no. 6 (May 29, 2021): 650. http://dx.doi.org/10.3390/antibiotics10060650.

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The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.

Дисертації з теми "LL-37 peptid":

1

Dannehl, Claudia. "Fragments of the human antimicrobial LL-37 and their interaction with model membranes." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6814/.

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A detailed description of the characteristics of antimicrobial peptides (AMPs) is highly demanded, since the resistance against traditional antibiotics is an emerging problem in medicine. They are part of the innate immune system in every organism, and they are very efficient in the protection against bacteria, viruses, fungi and even cancer cells. Their advantage is that their target is the cell membrane, in contrast to antibiotics which disturb the metabolism of the respective cell type. This allows AMPs to be more active and faster. The lack of an efficient therapy for some cancer types and the evolvement of resistance against existing antitumor agents make AMPs promising in cancer therapy besides being an alternative to traditional antibiotics. The aim of this work was the physical-chemical characterization of two fragments of LL-37, a human antimicrobial peptide from the cathelicidin family. The fragments LL-32 and LL-20 exhibited contrary behavior in biological experiments concerning their activity against bacterial cells, human cells and human cancer cells. LL-32 had even a higher activity than LL-37, while LL-20 had almost no effect. The interaction of the two fragments with model membranes was systematically studied in this work to understand their mode of action. Planar lipid films were mainly applied as model systems in combination with IR-spectroscopy and X-ray scattering methods. Circular Dichroism spectroscopy in bulk systems completed the results. In the first approach, the structure of the peptides was determined in aqueous solution and compared to the structure of the peptides at the air/water interface. In bulk, both peptides are in an unstructured conformation. Adsorbed and confined to at the air-water interface, the peptides differ drastically in their surface activity as well as in the secondary structure. While LL-32 transforms into an α-helix lying flat at the water surface, LL-20 stays partly unstructured. This is in good agreement with the high antimicrobial activity of LL-32. In the second approach, experiments with lipid monolayers as biomimetic models for the cell membrane were performed. It could be shown that the peptides fluidize condensed monolayers of negatively charged DPPG which can be related to the thinning of a bacterial cell membrane. An interaction of the peptides with zwitterionic PCs, as models for mammalian cells, was not clearly observed, even though LL-32 is haemolytic. In the third approach, the lipid monolayers were more adapted to the composition of human erythrocyte membranes by incorporating sphingomyelin (SM) into the PC monolayers. Physical-chemical properties of the lipid films were determined and the influence of the peptides on them was studied. It could be shown that the interaction of the more active LL-32 is strongly increased for heterogeneous lipid films containing both gel and fluid phases, while the interaction of LL-20 with the monolayers was unaffected. The results indicate an interaction of LL-32 with the membrane in a detergent-like way. Additionally, the modelling of the peptide interaction with cancer cells was performed by incorporating some negatively charged lipids into the PC/SM monolayers, but the increased charge had no effect on the interaction of LL-32. It was concluded, that the high anti-cancer activity of the peptide originates from the changed fluidity of cell membrane rather than from the increased surface charge. Furthermore, similarities to the physical-chemical properties of melittin, an AMP from the bee venom, were demonstrated.
Aufgrund der steigenden Resistenzen von Zellstämmen gegen traditionelle Therapeutika sind alternative medizinische Behandlungsmöglichkeiten für bakterielle Infektionen und Krebs stark gefragt. Antimikrobielle Peptide (AMPs) sind Bestandteil der unspezifischen Immunabwehr und kommen in jedem Organismus vor. AMPs lagern sich von außen an die Zellmembran an und zerstören ihre Integrität. Das macht sie effizient und vor allem schnell in der Wirkung gegen Bakterien, Viren, Pilzen und sogar Krebszellen. Das Ziel dieser Arbeit lag in der physikalisch-chemischen Charakterisierung zweier Peptidfragmente die unterschiedliche biologische Aktivität aufweisen. Die Peptide LL-32 und LL-20 waren Teile des humanen LL-37 aus der Kathelizidin-Familie. LL-32 wies eine stärke Aktivität als das Mutterpeptid auf, während LL-20 kaum aktiv gegen die verschiedenen Zelltypen war. In dieser Arbeit wurde die Wechselwirkung der Peptide mit Zellmembranen systematisch anhand von zweidimensionalen Modellmembranen in dieser Arbeit untersucht. Dafür wurden Filmwaagenmessungen mit IR-spektroskopischen und Röntgenstreumethoden gekoppelt. Circulardichroismus-Spektroskopie im Volumen komplementierte die Ergebnisse. In der ersten Näherung wurde die Struktur der Peptide in Lösung mit der Struktur an der Wasser/Luft-Grenzfläche verglichen. In wässriger Lösung sind beide Peptidfragmente unstrukturiert, nehmen jedoch eine α-helikale Sekundärstruktur an, wenn sie an die Wasser/Luft-Grenzfläche adsorbiert sind. Das biologisch unwirksamere LL-20 bleibt dabei teilweise ungeordnet. Das steht im Zusammenhang mit einer geringeren Grenzflächenaktivität des Peptids. In der Zweiten Näherung wurden Versuche mit Lipidmonoschichten als biomimetisches Modell für die Wechselwirkung mit der Zellmembran durchgeführt. Es konnte gezeigt werden, dass sich die Peptide fluidisierend auf negativ geladene Dipalmitylphosphatidylglycerol (DPPG) Monoschichten auswirken, was einer Membranverdünnung an Bakterienzellen entspricht. Eine Interaktion der Peptide mit zwitterionischem Phosphatidylcholin (PC), das als Modell für Säugetierzellen verwendet wurde, konnte nicht klar beobachtet werden, obwohl biologische Experimente das hämolytische Verhalten zumindest von LL-32 zeigten. In der dritten Näherung wurde das Membranmodell näher an die Membran von humanen Erythrozyten angepasst, indem gemischte Monoschichten aus Sphingomyelin (SM) und PC hergestellt wurden. Die physikalisch-chemischen Eigenschaften der Lipidfilme wurden zunächst ausgearbeitet und anschließend der Einfluss der Peptide untersucht. Es konnte anhand verschiedener Versuche gezeigt werden, dass die Wechselwirkung von LL-32 mit der Modellmembran verstärkt ist, wenn eine Koexistenz von fluiden und Gelphasen auftritt. Zusätzlich wurde die Wechselwirkung der Peptide mit der Membran von Krebszellen imitiert, indem ein geringer Anteil negativ geladener Lipide in die Monoschicht eingebaut wurde. Das hatte allerdings keinen nachweislichen Effekt, so dass geschlussfolgert werden konnte, dass die hohe Aktivität von LL-32 gegen Krebszellen ihren Grund in der veränderten Fluidität der Membran hat und nicht in der veränderten Oberflächenladung. Darüber hinaus wurden Ähnlichkeiten zu Melittin, einem AMP aus dem Bienengift, dargelegt. Die Ergebnisse dieser Arbeit sprechen für einen Detergenzien-artigen Wirkmechanismus des Peptids LL-32 an der Zellmembran.
2

Habes, Chahrazed. "Stimulation du signal calcique et de la migration des cellules cancéreuses mammaires par le peptide LL-37 : un mécanisme d’attachement membranaire impliquant les glycosaminoglycanes et les syndécanes." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR3807.

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Le peptide LL-37, peptide antimicrobien de l’immunité innée, est associé au développement tumoral. Sur des lignées cancéreuses mammaires. Il augmente le calcium intracellulaire et la migration. via l’activation de la voie PI3K/AKT et de canaux calciques. L’énantiomère (D)-LL-37 induit des effets similaires, excluant une interaction classique ligand-récepteur. Avec sa structure en hélice α amphipathique et sa charge nette +6, l’hypothèse était que le peptide utilise les charges négatives de glycanes sulfatés ou sialylés pour sa fixation membranaire avant d’induire ses activités. Des lectines végétales reconnaissant des structures glycaniques sialylées ou sulfatées inhibent la migration et le signal calcique induits par LL-37 mais l’implication de sialyltransférases n’a pas été démontrée. Des glycoaminoglycanes (GAGs) tels que les chondroïtine et héparine sulfatées, utilisés en tant que compétiteurs, ou une digestion enzymatique des GAGs (Chondroïtinase et héparinase) conduisent à une inhibition de 50 à 100% des activités migratoire et calcique induites par LL-37. L’inhibition de synthèse des GAGs par le Methylumbelliferyl β-D-xyloside ainsi qu’une diminution de la sulfatation par le chlorate de sodium confirment l’implication de ces glycanes sulfatés. Dans la perceptive d’identifier la ou les protéines glycosylées membranaires susceptibles de transduire les effets de LL-37, nous avons utilisé une approche ciblée en invalidant par siRNA la synthèse des protéines arborant des GAGs. Le syndécane 4 est impliqué dans les activités de LL-37. En conclusion, ces résultats soulignent l’implication de GAGs sulfatés portés par le syndécane 4 pour orienter la fixation de LL-37 à la membrane des cellules cancéreuses et médier ses activités pro-tumorales
Initially characterized by its antimicrobial activities, LL-37 has also been shown to significantly contribute to tumor development. On breast cancer cell lines, LL-37 increases intracellular calcium and their migration via the activation of PI3K/AKT signaling. Its all-D enantiomer (D)-LL-37 induces similar effects, which excludes an protein-protein interaction of LL-37 in a classic ligand-receptor manner. Its structure of an amphipathic a-helix with a net charge of +6 gave rise to the hypothesis that the peptide uses the negative charges of sulfoglycans or sialic acids to facilitate its attachment to the cell membrane and to induce its activities. Whereas several lectins, specifically attaching to sialylated or sulfated structures, blocked the activities of LL-37 on both calcium increase and cell migration, the suppression of several sialyltransferases had no effect. However, the competitive use of glycoaminoglycans (GAG) and chrondroitin and sulfated heparin, or treatment of the cell surface with chondroitinase and heparinase resulted in an activity loss of 50-100%. Similar results were obtained by confirmed by blocking the synthesis of GAGs with Methylumbelliferyl β-D-xyloside, and by suppression of glycan sulfurylation by sodium chlorate. Using a candidate approach by suppressing proteoglycan synthesis by RNA interference, syndecan 4 was shown to be involved in the activities of LL-37. This leads to the conclusion that sulfated GAGs linked to syndecans 4 guides the association of LL-37 to the membrane of cancer cells, thus being a mediator of its activities
3

El, Abbouni Sarah. "Microencapsulation of LL-37 Antimicrobial Peptide in PLGA." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/235.

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Antimicrobial peptides are key actors in organisms€™ immune systems. They play an important role in phagocytosis, breaking bacteria membranes. They destroy the microbes, keeping them from repairing themselves, and therefore do not promote antimicrobial resistance. LL37 is a peptide produced by the human body. It is a short amino acid chain that is particularly active on the skin and mucous membranes. It has antimicrobial and fungal activity as well as wound healing properties, which makes it a very interesting active substance in wound treatment. However, its fragile and sensitive structure is a challenge to its use. Nowadays, encapsulation in a biocompatible polymer system is a promising technique in drug delivery, and presents a solution to LL37 administration and delivery. LL37 is a hydrophilic active substance, it will be trapped in PLGA (poly (lactic-co-glycolic acid)) by double emulsion and the microspheres will be shaped and stabilized by solvent evaporation. The capsules will be characterized by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy. Their main features, drug loading, encapsulation efficiency and release profile, are determined using the Bradford assay. Since the peptide is expensive and delicate, it is important to optimize its encapsulation. For that reason, we will adapt the process to have the best drug loading as possible using water in oil in oil emulsions. For an external use, the capsules would be used over a few days, so having a fast release is very relevant. The larger the specific surface area, the faster the diffusion. For that reason, we will also study the impact of porosity on the release profile. As a result, different types of capsules will be synthesized, with higher porosity and by two processes: aqueous double emulsion and oil double emulsion. Their characteristic features and impact on bacterial pathogens will be determined and compared in order to determine their optimal synthesis process and formulation in given conditions of use.
4

Filewod, Niall Christopher Jack. "Immunomodulatory effects of LL-37 in the epithelia." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/927.

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The cationic host defence peptide LL-37 is an immunomodulatory agent that plays an important role in epithelial innate immunity. Previously, concentrations of LL-37 thought to represent levels present during inflammation have been shown to elicit the production of cytokines and chemokines by epithelial cells. To investigate the potential of lower concentrations of LL-37 to alter epithelial cell responses, normal primary keratinocytes and bronchial epithelial cells were treated with pro-inflammatory stimuli in the presence or absence of 1 – 3 μg/ml LL-37. Low, physiologically relevant concentrations of LL-37 synergistically increased IL-8 production by both proliferating and differentiated keratinocytes in response to IL-1β and the TLR5 agonist flagellin, and synergistically increased IL-8 production by bronchial epithelial cells in response to IL-1β, flagellin, and the TLR2/1 agonist PAM3CSK4. Treatment of bronchial epithelial cells with LL-37 and the TLR3 agonist poly(I:C) resulted in synergistic increases in IL-8 release and cytotoxicity. The synergistic increase in IL-8 production observed when keratinocytes were co-stimulated with flagellin and LL-37 was suppressed by pretreatment with inhibitors of Src-family kinase signalling and NF-κB translocation. These data suggest that low concentrations of LL-37 may alter epithelial responses to microbes in vivo. Microarray analysis of keratinocyte transcriptional responses after LL-37 treatment suggest that LL-37 may alter the expression of growth factors and a number of genes important to innate immune responses. LL-37 may thus play a more important role than previously suspected in the regulation of epithelial inflammation; an improved understanding of the mechanisms by which LL-37 alters chemokine responses could lead to the development of novel anti-infective and anti-inflammatory therapeutics.
5

Carlsson, Martin, and Johan Humlén. "Effekter av den antimikrobiella peptiden LL-37 på humana osteoblasters viabilitet." Thesis, Malmö högskola, Odontologiska fakulteten (OD), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-19902.

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Den antimikrobiella peptiden LL-37 finns uttryckt i alla kroppens slemhinnor och lagras i stora mängder i sekundära granula hos neutrofiler och monocyter. Förutom dess antimikrobiella effekt uppvisar LL-37 pro- alternativt anti-apoptotisk effekt på eukaryota celler beroende på celltyp. I denna studie visar vi för första gången den pro-apoptotiska effekten av LL-37 på den humana osteoblastcellinjen MG63. Vid stimulering med 4μM iakttogs en reduktion av cellantalet med 40% och en utbredd celldöd kunde fastställas genom Trypan Blue-infärgning. Genom flödescytometri sågs en förhöjd andel annexin V-positiva celler och en ökning aktivt kaspas-3 kunde påvisas genom ELISA efter stimulering med 4μM LL-37. Tillsammans med morfologiska tecken såsom skrumpning kan den pro-apoptotiska effekten av LL-37 fastställas. En kraftig och ihållande ökning av intracellulära Ca2+-koncentrationer kunde ses i Fluo 4-AM-infärgade celler i konfokalmikroskop efter stimulering med 4μM LL-37 men inte då Ca2+ exkluderades från mediet. Blockering av den dominerande spänningsberoende Ca2+- kanalen av L-typ med nifedipin hade ingen effekt på de tilltagande intracellulära Ca2+-koncentrationerna vilket påvisar en mekanism som ej involverar den kanalen. I efterföljande försök sågs dessutom att LL-37 reducerade cellantalet oberoende om Ca2+ fanns närvarande i mediet eller ej. Sammanfattningsvis visar data från denna studie att LL-37 reducerar antalet MG63-celler genom pro-apoptotisk effekt i koncentrationer som associerats med kronisk parodontit. Vi föreslår att verkningsmekanismen för apoptos sker via en permeabilisering av plasmamembranet, där tilltagande Ca2+-koncentrationer snarare får ses som en bieffekt av den förlorade membranintegriteten än en central faktor vid den apoptotiska signaleringen i detta system.
6

Ghannad, Mona. "Design and Synthesis of Collagen-binding Anti-microbial Proteins." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19981.

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The Herpes simplex virus (HSV) is a virus that commonly infects the skin, and mucous membrane of the mouth, genitalia, and the eye. HSV-1 is the strain that is most commonly associated with corneal infections, and it is the most frequent cause of corneal blindness in North America [1]. Currently no cure is available, and many limitations are characterized by the currently available synthetic antiviral drugs, which suggest the need for other potential drug alternatives and delivery strategies. Anti-microbial peptides are naturally occurring peptides that are potent killers of a broad range of micro-organisms, including bacteria, fungi, and viruses [2]. AMPs are known to be a key component of the innate immune response at the human ocular surface. The human cathelicidin-derived AMP, LL-37, expressed in human corneal epithelial cells provides a wide range of protection against viral pathogens such as HSV-1 [3]. My thesis research addressed the design and recombinant production of hybrid AMP sequences containing LL-37 with the potential ability to form chemical or physical associations with a Collagen scaffold material, such as those used in current artificial cornea constructs to address the need for alternative anti-viral drugs. Three fusion proteins were tested, and compared for feasible design anti-microbial peptide expression and purification in E. coli. It was illustrated that the thioredoxin and SUMO fusion systems are good candidates for successful recombinant production of active designed peptides. The point-mutated LL-37 sequence was successfully expressed and purified using the thioredoxin fusion system. It was demonstrated that this modified LL-37 was effective against HSV-1 infection. The SUMO system was used to express the bio-functional LL-37 containing a collagen-binding sequence. Further work is required to address issues regarding recombinant AMP production, such as increasing enzymatic cleavage efficacy, and minimizing proteolytic degradation or modification.
7

Li, Yue Xin. "The human cationic host defense peptide LL-37 modulates neutrophil apoptosis and chemokine responses." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31726.

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LL-37 is a human cationic peptide expressed primarily by neutrophils and epithelial cells. It is a 37 amino acid peptide that belongs to the cathelicidin family of the cationic host defense peptides. Accumulating evidence has demonstrated that LL-37 has multiple immunomodulatory properties. The modulatory effects of LL-37 on neutrophils were investigated here, and LL-37 was shown to be a potent inhibitor of spontaneous apoptosis in human neutrophils, signalling through P2X₇ receptors and G-protein-coupled receptors other than the formyl peptide receptor-like- 1 molecule. Inhibition of neutrophil apoptosis involved modulation of Mcl-1 expression, inhibition of BID and procaspase-3 cleavage, and the activation of phosphatidylinositol-3 kinase and protein kinase C but not the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (ERK1/2) pathway. In addition, LL-37 modified neutrophil cytokine/chemokine responses to pro-inflammatory stimuli in a stimulus-specific manner. Specifically, LL-37 abrogated LPS-induced TNF-a cytokine production while enhancing IL-1β elicited release of TNF-a as well as a number of chemokines including IL-8, Gro-a, CCL-22 and Mip-la . The increased release of chemokines induced synergistically by LL-37 and IL-1β resulted from de novo protein synthesis and was found to be associated with the signalling through the ERK1/2 and p38 MAP kinases and nuclear factor κΒ pathways. These novel immunomodulatory properties of LL-37 may contribute to peptide-mediated enhancement of innate host defenses against acute infection and are of considerable significance in the development of such peptides and their synthetic analogs as potential therapeutics for use against multiple antibiotic-resistant infectious diseases.
Science, Faculty of
Microbiology and Immunology, Department of
Graduate
8

Zhang, P. "Identification of staphylococcal genes involved in resistance to the human antimicrobial peptide LL-37." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1380282/.

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Staphylococcus aureus is well-known for its ability to acquire resistance to a broad range of antimicrobial agents and a limited number of commercially available antibiotics exist that are active against multidrug resistant strains. Antimicrobial peptides have been suggested as promising alternatives to current antimicrobials due to their potent antimicrobial activity against a broad range of microorganisms including multidrug resistant bacteria, and a membrane-lytic mode of action that is thought to have low possibility of inducing bacterial resistance. This study describes the identification of S. aureus genes involved in resistance to the human cationic antimicrobial peptide LL-37, with a particular interest in the effects of a physiological concentration of bicarbonate on the resistance mechanism. Transposon mutagenesis and recombinase-based in vivo expression technology systems were designed to enable genome-wide screening. A S. aureus transposon mutant library was screened for increased resistance to LL-37 in the presence of bicarbonate. Mutants with insertions in yycH and yycI, demonstrated bicarbonate-dependent resistance to LL-37. Both yycH and yycI form part of a predicted operon yycFGHI in S. aureus, and have been shown to be suppressors of an essential two component system YycFG in B. subtilis that regulates cell wall metabolism. The resistance of S. aureus small colony variants (SCVs) to LL-37 was also investigated. SCVs defective in hemB, menD or aroD, demonstrated bicarbonate-dependent resistance to LL-37. Furthermore, SigB (a global regulator) and TcaR (an activator of protein A) were found to exert opposite effects on resistance to LL-37 in the presence of bicarbonate. Strains defective in TcaR showed bicarbonate-dependent resistance to LL-37, interestingly, this resistance was abolished by either deleting sigB or repairing tcaR in these strains. These data suggest that YycFG, SigB, TcaR and the SCV phenotype may play important roles in resistance to LL-37 under in vivo conditions where bicarbonate is present.
9

Milhan, Noala Vicensoto Moreira. "Avaliação do peptideo LL-37 em contato com células-tronco da polpa dentária /." São José dos Campos, 2017. http://hdl.handle.net/11449/149791.

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Orientador: Samira Esteves Afonso Camargo
Banca: Luana Marotta Reis de Vasconcellos
Banca: Mônica Ghislaine Oliveira Alves
Banca: Cristina Pacheco Soares
Banca: Cacio de Moura Netto
Resumo: O peptídeoLL-37 (catelicidina derivada de humano), é liberado por algumas células humanas e capaz de neutralizar os tecidos com lipopolissacarídeo (LPS), além de atrair células da polpa, e induzir a angiogênese, características que o tornam um possível adjunto para a regeneração do complexo dentino-pulpar. O objetivo desse trabalho foi avaliar in vitro a biocompatibilidade do peptídeo LL-37 nas concentrações de 5 e 10 µg/mL, e sua possível atuação na diferenciação de células-tronco da polpa dentária (DPSC) para odontoblastoslike. Com esse propósito, foram avaliados: (a) a citotoxicidade, pelo teste MTT; (b) a genotoxicidade, através do ensaio do micronúcleo; (c) a produção e quantificação de óxido nítrico; (d) as fases do ciclo celular, por citometria; (e) a expressão de alguns genes associados à formação de tecido mineralizado, através do teste qRT-PCR; (f) o conteúdo de proteína total; (g) a atividade de fosfatase alcalina (ALP); e (h) a produção de sialofosfoproteína dentinária (DSPP), pelo ensaio imunoenzimático ELISA. Foi observado que as concentrações de 5 e 10 µg/mL de LL-37 não foram citotóxicas e ainda aumentaram, em geral, a viabilidade celular (p<0,05), sendo que os maiores valores de absorbância foram observados no 3° dia de contato. As concentrações testadas também não induziram genotoxicidade, após 7 dias de contato, tendo sido genotóxico apenas o grupo controle positivo (EMS) (p<0,05). Ainda, não foi observado diferença estatisticamente significativa na produção de nitrito, pelas células expostas ao LL-37 após 7 dias, em ambas as concentrações. A análise do ciclo celular, evidenciou maior porcentual de células na fase G0/G1, em todos os grupos (p<0,05). Quando estes foram comparados, foi observado maior quantidade de células na fase G0/G1 na concentração de... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract : The LL 37 peptide (human derived cathelicidin) is released by some human cells and able of neutralizing the tissues that present lipopolysaccharide (LPS), as well as, attracts pulp cells and induces angiogenesis; characteristics that makes it a possible adjunct for regeneration of the dentin-pulp complex. The aim of this study was evaluate in vitro the biocompatibility of LL-37 in the concentrations of 5 and 10 µg/mL, and its possible performance in the differentiation of dental pulp stem cells (DPSC) into odontoblasts-like cells. For this purpose, it was evaluated: (a) the cytotoxicity by MTT assay; (b) the genotoxicity by the micronucleus test; (c) the production and quantification of nitric oxide; (d) the cell cycle, by flow cytometry; (e) the expression of genes associated with the mineralization by qRT-PCR; (f) the total protein content; (g) the alkaline phosphatase activity (ALP); and (h) the production of dentine sialofosfoprotein (DSPP) by indirect enzyme-linked immunosorbent assay (ELISA). It was observed that the concentrations of 5 and 10 µg/ml of LL-37 were not cytotoxic, in addition to they increased, in general, the cell viability (p<0,05). Moreover, higher absorbance values were observed on 3rd day of contact. After 7 days, the tested concentrations also did not induce genotoxicity, (p<0,05); only the positive control group (EMS) was genotoxic (p<0.05). Furthermore, there was not statistical significance in the nitrite production by the cells exposed to LL-37 for 7 days, in both concentrations. The cell cycle test showed higher percentage of cells in the phase G0/G1 in all groups (p<0.05). When they were compared, it was noticied that concentration of 10 ug/ml of LL-37 arrested the cells in G0/G1 compared to the control group (p<0.05). On the other hand, the control group, exhibited higher amount of cells in G2 and mitosis...(Resumo completo, clicar acesso eletrônico abaixo)
Doutor
10

Zreika, Sami. "Etude de l'impact de la protéine antimicrobienne humaine hCAP18/LL-37 sur le cancer du sein." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4052.

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Le peptide hCAP18/LL-37, une partie de la défense immunitaire innée, a maintenant été reconnu comme multifonctionnelle pour les cellules eucaryotes. Nos études démontrent sa contribution au développement du cancer, montrant qu'il est surexprimé dans la plupart des tumeurs mammaires humaines, active la signalisation la famille de ERBB et augmente le potentiel métastatique des cellules cancéreuses du sein. Notre comparaison des deux lignées du cancer du sein n'a pas révélé de récepteurs communs, mais une structure peptidique identiques mais de chiralité différente est pré requis pour le peptide dans toutes ses activités. Nous émettons l'hypothèse que LL-37 active indirectement des récepteurs transmembranaires en se liant à la membrane cellulaire. Des peptides tronqués dérivés de LL-37 inhibent ses activités et peuvent aider à concevoir une future thérapie anticancéreuse
The peptide hCAP18/LL-37, part of the innate immune defense, has now been recognized as multifunctional for eukaryotic cells. Our studies demonstrate its contribution to cancer development, showing that it is overexpressed in most human breast tumors, activates ERBB signaling and increases the metastatic potential of breast cancer cells. Our comparison on two breast cancer lines did not reveal any common receptors but identical structural prerequisites for the peptide in all its activities. We hypothesize that LL-37 indirectly activates transmembrane receptors by attaching to the cellular membrane. Truncated derivatives inhibit its activities and may help to design a future anticancer therapy

Частини книг з теми "LL-37 peptid":

1

Sorkin, M., F. Jacobsen, D. Mittler, T. Hirsch, A. Gerhards, M. Lehnhardt, H. U. Steinau, and L. Steinstraesser. "Kutane adenovirale Gentherapie mit humanem Host Defense Peptid LL-37 in infizierten Verbrennungswunden der Ratte." In Chirurgisches Forum 2006, 357–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-34668-6_123.

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2

Beaumont, Paula E., Hsin-Ni Li, and Donald J. Davidson. "LL-37: An Immunomodulatory Antimicrobial Host Defence Peptide." In Antimicrobial Peptides and Innate Immunity, 97–121. Basel: Springer Basel, 2012. http://dx.doi.org/10.1007/978-3-0348-0541-4_4.

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3

Nylén, Frank, Peter Bergman, Gudmundur H. Gudmundsson, and Birgitta Agerberth. "Assays for Identifying Inducers of the Antimicrobial Peptide LL-37." In Methods in Molecular Biology, 271–81. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-6737-7_19.

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4

Wang, Guangshun, Jayaram Lakshmaiah Narayana, Biswajit Mishra, Yingxia Zhang, Fangyu Wang, Chunfeng Wang, D. Zarena, Tamara Lushnikova, and Xiuqing Wang. "Design of Antimicrobial Peptides: Progress Made with Human Cathelicidin LL-37." In Advances in Experimental Medicine and Biology, 215–40. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-3588-4_12.

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Тези доповідей конференцій з теми "LL-37 peptid":

1

Biondi, Barbara, Silvia Millan, Fernando Formaggio, Alessandra Semenzato, and Cristina Peggion. "Synthesis and conformationof short peptides modeled after peptide LL-37." In 35th European Peptide Symposium. Prompt Scientific Publishing, 2018. http://dx.doi.org/10.17952/35eps.2018.195.

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2

Lee, Jia-Yi, Chung-Yih Wang, Chi-Fang Huang, and An-Ting Cheng. "Interdigitated electrodes based on impedance biosensor for sensing peptide LL-37." In 2011 33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2011. http://dx.doi.org/10.1109/iembs.2011.6089899.

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3

Wang, Guangshun. "Design potent peptide antibiotics against the ESKAPE pathogens based on human antimicrobial peptide LL-37." In 4th International Electronic Conference on Medicinal Chemistry. Basel, Switzerland: MDPI, 2018. http://dx.doi.org/10.3390/ecmc-4-05882.

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4

Lu, Xiuxiu, Qi Zhang, Guowei Song, Xiaodai Cui, Jian Yang, and Baoyuan Zhang. "The Changes of Plasma Antibacterial Peptide ll-37 in the Bloodstream Infected Children." In Selection of Abstracts From NCE 2016. American Academy of Pediatrics, 2018. http://dx.doi.org/10.1542/peds.141.1_meetingabstract.331.

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5

Valencia, Yeny Y. P., Gabriel C. A. da Hora, and Thereza A. Soares. "INTERAÇÃO DE AGREGADOS DE POPG NA PRESENÇA DE PEPTIDEO ANTIMICROBIANOS LL 37." In Encontro Anual da biofisica 2019. São Paulo: Editora Blucher, 2019. http://dx.doi.org/10.5151/biofisica2019-23.

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6

McCaskill, Michael L., Jill A. Poole, Diane S. Allen-Gipson, Jane M. DeVasure, and Todd A. Wyatt. "Ethanol Consumption Leads To Reduced Levels Of Lung Tissue Vitamin D And Anti-Microbial Peptide LL-37 In C57Bl/6 Mice." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a4670.

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7

Krasnodembskaya, Anna, Yuanlin Song, Jae-Woo Lee, and Michael A. Matthay. "Human Mesenchymal Stem Cells Exert Antimicrobial Activity In Vitro And In Vivo In Part Through The Secretion Of The Antimicrobial Peptide LL-37." In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a1246.

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8

Schrumpf, Jasmijn, Renate Verhoosel та Pieter Hiemstra. "Vitamin D-mediated expression of the antimicrobial peptide hCAP18/LL-37 and killing of non-typeablehaemophilus influenzae(NTHi) is reduced after 14 days exposure to TNF-α and IL-1β in primary bronchial epithelial cells (PBEC)". У Annual Congress 2015. European Respiratory Society, 2015. http://dx.doi.org/10.1183/13993003.congress-2015.oa1785.

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