scholarly journals Proteomic Adaptation of Streptococcus pneumoniae to the Human Antimicrobial Peptide LL-37

2020 ◽  
Vol 8 (3) ◽  
pp. 413 ◽  
Author(s):  
Pierre-Alexander Mücke ◽  
Sandra Maaß ◽  
Thomas P. Kohler ◽  
Sven Hammerschmidt ◽  
Dörte Becher
Keyword(s):  
Streptococcus Pneumoniae ◽  
Drug Targets ◽  
High Resolution Mass Spectrometry ◽  
Teichoic Acid ◽  
Antimicrobial Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Bacterial Membranes ◽  
Adaptation Mechanisms ◽  
Pore Complexes

Secreted antimicrobial peptides (AMPs) are an important part of the human innate immune system and prevent local and systemic infections by inhibiting bacterial growth in a concentration-dependent manner. In the respiratory tract, the cationic peptide LL-37 is one of the most abundant AMPs and capable of building pore complexes in usually negatively charged bacterial membranes, leading to the destruction of bacteria. However, the adaptation mechanisms of several pathogens to LL-37 are already described and are known to weaken the antimicrobial effect of the AMP, for instance, by repulsion, export or degradation of the peptide. This study examines proteome-wide changes in Streptococcus pneumoniae D39, the leading cause of bacterial pneumonia, in response to physiological concentrations of LL-37 by high-resolution mass spectrometry. Our data indicate that pneumococci may use some of the known adaptation mechanisms to reduce the effect of LL-37 on their physiology, too. Additionally, several proteins seem to be involved in resistance to AMPs which have not been related to this process before, such as the teichoic acid flippase TacF (SPD_1128). Understanding colonization- and infection-relevant adaptations of the pneumococcus to AMPs, especially LL-37, could finally uncover new drug targets to weaken the burden of this widespread pathogen.

HPLC-Based Activity Profiling for GABAA Receptor Modulators in Searsia pyroides Using a Larval Zebrafish Locomotor Assay

Planta Medica ◽  
2017 ◽  
Vol 83 (14/15) ◽  
pp. 1169-1175 ◽  
Author(s):  
Fahimeh Moradi-Afrapoli ◽  
Hannes van der Merwe ◽  
Maria De Mieri ◽  
Anke Wilhelm ◽  
Marco Stadler ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
High Resolution Mass Spectrometry ◽  
Aminobutyric Acid ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Concentration Dependent Manner ◽  
Hplc Fraction ◽  
Chloride Currents ◽  
Zebrafish Larvae ◽  
Activity Profiling

AbstractA dichloromethane extract from leaves of Searsia pyroides potentiated gamma aminobutyric acid-induced chloride currents by 171.8 ± 54% when tested at 100 µg/mL in Xenopus oocytes transiently expressing gamma aminobutyric acid type A receptors composed of α 1 β 2 γ 2s subunits. In zebrafish larvae, the extract significantly lowered pentylenetetrazol-provoked locomotion when tested at 4 µg/mL. Active compounds of the extract were tracked with the aid of HPLC-based activity profiling utilizing a previously validated zebrafish larval locomotor activity assay. From two active HPLC fractions, compounds 1 – 3 were isolated. Structurally related compounds 4 – 6 were purified from a later eluting inactive HPLC fraction. With the aid of 1H and 13C NMR and high-resolution mass spectrometry, compounds 1 – 6 were identified as analogues of anacardic acid. Compounds 1 – 3 led to a concentration-dependent decrease of pentylenetetrazol-provoked locomotion in the zebrafish larvae model, while 4 – 6 were inactive. Compounds 1 – 3 enhanced gamma aminobutyric acid-induced chloride currents in Xenopus oocytes in a concentration-dependent manner, while 4 – 6 only showed marginal enhancements of gamma aminobutyric acid-induced chloride currents. Compounds 2, 3, and 5 have not been reported previously.

scholarly journals Proteolysis-Targeting Chimeras (PROTACs) Based on Macrocyclic Tetrapeptides Selectively Degrade Class I Histone Deacetylases 1–3

2020 ◽  
Author(s):  
Martin Roatsch ◽  
Anja Vogelmann ◽  
Daniel Herp ◽  
Manfred Jung ◽  
Christian Adam Olsen
Keyword(s):  
Histone Deacetylases ◽  
Drug Targets ◽  
Cyclic Peptides ◽  
Class I ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Design Synthesis ◽  
Histone Hyperacetylation ◽  
Target Binding ◽  
Class I Hdacs

Histone deacetylases (HDACs) remove acetyl groups from histone proteins and are implicated in gene regulation. They have been recognized as drug targets for treatment of cancer and other human diseases and several inhibitors are already clinically used. Here, we report the design, synthesis, and cellular characterization of a proteolysis-targeting chimera (PROTAC) capable of selectively degrading class I HDACs 1–3 in cells. These novel chemotypes are based on potent and class I-selective macrocyclic tetrapeptide inhibitors, which were linked to thalidomide by modular synthesis, employing copper-catalyzed azide–alkyne “click” chemistry. In HEK293T cells, these conjugates lead to degradation of HDAC1–3 in a time- and concentration-dependent manner. Concomitant histone hyperacetylation without leading to cytotoxic effects was observed by western blot. These chemotypes enable the study of the biological roles of class I HDAC enzymes by short-term temporal deletion. Our compounds represent the first examples of degraders with demonstrated selectivity for class I HDACs 1–3. Importantly, this study highlights the utility of cyclic peptides as target-binding elements for PROTAC design in general.

scholarly journals Capsule Independent Antimicrobial Activity Induced by Nanochitosan against Streptococcus pneumoniae

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2924
Author(s):  
Fulwah Y. Alqahtani ◽  
Fadilah S. Aleanizy ◽  
Eram El Tahir ◽  
Hessa Alowais ◽  
Assalh Binkelaib ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Streptococcus Pneumoniae ◽  
Polymeric Nanoparticles ◽  
Wide Spectrum ◽  
A549 Cells ◽  
Community Acquired Pneumonia ◽  
High Morbidity ◽  
Dependent Manner ◽  
Hemolysis Assay ◽  
Concentration Dependent Manner

Background: Streptococcus pneumoniae remains a major cause of community-acquired pneumonia, meningitis, and other diseases, contributing significantly to high morbidity and mortality worldwide. Although it responds to antibiotics, their use is becoming limited due to the rise in antibiotic resistance, which necessitates the development of new therapeutics. Nanotechnology is used to counteract antimicrobial resistance. In this regard, polymeric nanoparticles (NPs) made of natural, biodegradable, biocompatible, and cationic polymers such as Chitosan (CNPs) exhibit wide-spectrum antimicrobial activity. Therefore, this study aimed to prepare CNPs, characterize their physiochemical characteristics: particle size (PZ), polydispersity index (PDI), and zeta potential (ZP), and investigate their antimicrobial activity against Streptococcus pneumoniae TIGR4 (virulent serotype 4) and its capsular mutant (∆cps). Methods: CNPs were prepared at 1, 2.5, and 5 mg/mL concentrations using the ion gelation method. Then, PZ, PDI, and ZP were characterized using a Zetasizer. Transmission electron microscopy (TEM) was used to visualize the CNP’s morphology. Broth and agar dilution methods were used to assess their antimicrobial activity. Cytotoxicity of prepared NPs on A549 cells and their effect on pneumococcal hemolysis were also investigated. Results: Spherical CNPs were produced with PZ ranging from 133.3 nm ± 0.57 to 423 nm ± 12.93 PDI < 0.35, and ZP from 19 ± 0.115 to 27 ± 0.819. The prepared CNPs exhibited antibacterial activity against TIGR4 and its capsule mutant with a minimum inhibitory concentration (MIC90) of 0.5 to 2.5 mg/mL in a non-acidic environment. The hemolysis assay results revealed that CNPs reduced bacterial hemolysis in a concentration-dependent manner. Their mammalian cytotoxicity results indicated that CNPs formed from low concentrations of Chitosan (Cs) were cytocompatible. Conclusion: Nanochitosan particles showed anti-pneumococcal activity regardless of the presence of capsules. They resulted in a concentration-dependent reduction in bacterial hemolysis and were cytocompatible at a lower concentration of Cs. These findings highlight the potential of CNPs in the treatment of pneumococcal diseases.

scholarly journals Inhibition of Streptococcus pneumoniae autolysins highlight distinct differences between chemical and genetic inactivation

2020 ◽  
Author(s):  
Brad A Haubrich ◽  
Saman Nayyab ◽  
Caroline Williams ◽  
Andrew Whitman ◽  
Tahl Zimmerman ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Screening ◽  
Dependent Manner ◽  
Cell Wall Metabolism ◽  
Phenotypic Analysis ◽  
Concentration Dependent Manner ◽  
Chemical Inactivation ◽  
Autolytic Activity ◽  
The Difference ◽  
Induced Autolysis

AbstractDespite renewed interest, development of chemical biology methods to study peptidoglycan metabolism has lagged in comparison to the glycobiology field in general. To address this, a panel of diamides were screened against the Gram-positive pathogen Streptococcus pneumoniae to identify inhibitors of bacterial growth. The screen identified the diamide fgkc as a narrow spectrum bacteriostatic inhibitor of S. pneumoniae growth with an MIC of 7.8 μM. The diamide inhibited detergent-induced autolysis in a concentration dependent manner indicating peptidoglycan degradation as the mode-of-action. Genetic screening of autolysin mutants suggested LytB, an endo-N-acetylglucosaminidase, involved in cell division as the potential target. Surprisingly, biochemical, and phenotypic analysis contradicted the genetic screen results. Phenotypic studies with the Δlytb strain illustrate the difference between genetic and chemical inactivation of autolysins. These findings suggest that meta-phenotypes including autolytic activity, cell morphology, and genetic screening can be the result of the complex interaction of one or more possible pathways that are connected to cell wall metabolism.

scholarly journals Phytochemical Screening, Antibacterial, Antifungal, Antiviral, Cytotoxic, and Anti-Quorum-Sensing Properties of Teucrium polium L. Aerial Parts Methanolic Extract

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1418
Author(s):  
Mousa Alreshidi ◽  
Emira Noumi ◽  
Lamjed Bouslama ◽  
Ozgur Ceylan ◽  
Vajid N. Veettil ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Methanolic Extract ◽  
High Resolution Mass Spectrometry ◽  
Antimicrobial Activities ◽  
Dependent Manner ◽  
Bacterial Strains ◽  
Concentration Dependent Manner ◽  
African Green Monkey Kidney ◽  
Teucrium Polium ◽  
Teucrium Polium L

The chemical profile of Teucrium polium L. (T. polium) methanolic extract was tested using liquid chromatography coupled with high resolution mass spectrometry (HR-LCMS). Disc diffusion and microdilution assays were used for the antimicrobial activities. Coxsackievirus B-3 (CVB3) and Herpes simplex virus type 2 (HSV-2) were used for the antiviral activities. Chromobacterium violaceum (ATCC 12472 and CV026) and Pseudomonas aeruginosa PAO1 were used as starter strains for the anti-quorum sensing tests. Isoprenoids are the main class of compounds identified, and 13R-hydroxy-9E,11Z-octadecadienoic acid, valtratum, rhoifolin, sericetin diacetate, and dihydrosamidin were the dominant phytoconstituents. The highest mean diameter of growth inhibition zone was recorded for Acinetobacter baumannii (19.33 ± 1.15 mm). The minimal inhibitory concentrations were ranging from 6.25 to 25 mg/mL for bacterial strains, and from 6.25 to 25 mg/mL for Candida species. The 50% cytotoxic concentration on VERO (African Green Monkey Kidney) cell lines was estimated at 209 µg/mL. No antiviral activity was recorded. Additionally, T. polium extract was able to inhibit P. aeruginosa PAO1 motility in a concentration-dependent manner. However, the tested extract was able to inhibit 23.66% of the swarming and 35.25% of swimming capacities of PAO1 at 100 µg/mL. These results highlighted the role of germander as a potent antimicrobial agent that can interfere with the virulence factors controlled by the quorum-sensing systems.

scholarly journals Proteolysis-Targeting Chimeras (PROTACs) Based on Macrocyclic Tetrapeptides Selectively Degrade Class I Histone Deacetylases 1–3

2020 ◽  
Author(s):  
Martin Roatsch ◽  
Anja Vogelmann ◽  
Daniel Herp ◽  
Manfred Jung ◽  
Christian Adam Olsen
Keyword(s):  
Histone Deacetylases ◽  
Drug Targets ◽  
Cyclic Peptides ◽  
Class I ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Design Synthesis ◽  
Histone Hyperacetylation ◽  
Target Binding ◽  
Class I Hdacs

Histone deacetylases (HDACs) remove acetyl groups from histone proteins and are implicated in gene regulation. They have been recognized as drug targets for treatment of cancer and other human diseases and several inhibitors are already clinically used. Here, we report the design, synthesis, and cellular characterization of a proteolysis-targeting chimera (PROTAC) capable of selectively degrading class I HDACs 1–3 in cells. These novel chemotypes are based on potent and class I-selective macrocyclic tetrapeptide inhibitors, which were linked to thalidomide by modular synthesis, employing copper-catalyzed azide–alkyne “click” chemistry. In HEK293T cells, these conjugates lead to degradation of HDAC1–3 in a time- and concentration-dependent manner. Concomitant histone hyperacetylation without leading to cytotoxic effects was observed by western blot. These chemotypes enable the study of the biological roles of class I HDAC enzymes by short-term temporal deletion. Our compounds represent the first examples of degraders with demonstrated selectivity for class I HDACs 1–3. Importantly, this study highlights the utility of cyclic peptides as target-binding elements for PROTAC design in general.

scholarly journals Application of multi-omics technology for the elucidation of anti-pneumococcal activity of 3-acyl-2-phenylamino-1,4-dihydroquinolin-4-one (APDQ) derivative against Streptococcus pneumoniae

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sang-Yeop Lee ◽  
Hayoung Lee ◽  
Sung Ho Yun ◽  
Sangmi Jun ◽  
Yujeong Lee ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Underlying Mechanism ◽  
Differentially Expressed ◽  
Dependent Manner ◽  
Rna Seq ◽  
Concentration Dependent Manner ◽  
Peptidoglycan Biosynthesis ◽  
Omics Analysis ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

AbstractStreptococcus pneumoniae is one of Gram-positive pathogen that causes invasive pneumococcal disease. Nowadays, many S. pneumoniae strains are resistant to commonly used antibiotics such as β-lactams and macrolides. 3-Acyl-2-phenylamino-1,4-dihydroquinolin-4-one (APDQ) derivatives are known as novel chemicals having anti-pneumococcal activity against S. pneumoniae. The underlying mechanism of the anti-pneumococcal activity of this inhibitor remains unknown. Therefore, we tried to find the anti-pneumococcal mechanism of APDQ230122, one of the APDQ derivatives active against S. pneumoniae. We performed transcriptomic analysis (RNA-Seq) and proteomic analysis (LC–MS/MS analysis) to get differentially expressed genes (DEG) and differentially expressed proteins (DEP) of S. pneumoniae 521 treated with sub-inhibitory concentrations of APDQ230122 and elucidated the comprehensive expression changes of genes and proteins using multi-omics analysis. As a result, genes or proteins of peptidoglycan biosynthesis and DNA replication were significantly down-regulated. Electron microscopy analysis revealed that the structure of peptidoglycan was damaged by APDQ230122 in a chemical concentration-dependent manner. Therefore, we suggest peptidoglycan biosynthesis is a major target of APDQ230122. Multi-omics analysis can provide us useful information to elucidate anti-pneumococcal activity of APDQ230122.

scholarly journals Local inhibition of PRC2 activity by H3.3K27M drives DNA replication defects through misregulation of the JNK pathway

2019 ◽  
Author(s):  
Kamila Delaney ◽  
Maude Strobino ◽  
Joanna M. Wenda ◽  
Andrzej Pankowski ◽  
Florian A. Steiner
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Drug Targets ◽  
Cell Cycle Progression ◽  
Human Tumor ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cycle Progression ◽  
Jnk Pathway ◽  
Local Inhibition

AbstractSubstitution of lysine 27 with methionine in histone H3.3 is a recently discovered driver mutation of pediatric high-grade gliomas. Mutant tumor cells show decreased levels and altered distribution of H3K27me3. How these chromatin changes are established genome-wide and lead to tumorigenesis only in specific tissues remains unclear. Here we show that H3.3K27M-mediated alterations in H3K27me3 distribution result in ectopic DNA replication and cell cycle progression of germ cells in Caenorhabditis elegans. By genetically inducing changes in the H3.3 distribution, we demonstrate that both H3.3K27M oncohistone incorporation and pre-existing H3K27me3 act locally and antagonistically on Polycomb Repressive Complex 2 (PRC2) in a concentration-dependent manner, explaining the observed H3K27me3 distribution in mutant cells. The altered heterochromatin patterns lead to extensive misregulation of gene expression. Through unbiased genetic screening, we found that inhibiting JNK pathway components, which are overexpressed in H3.3K27M cells, suppresses the ectopic DNA replication and cell cycle progression without rescuing the altered H3K27me3 distribution. Moreover, we show that JNK inhibition suppresses the replicative fate in human tumor-derived H3.3K27M cells, thus establishing C. elegans as a powerful model for the identification of potential drug targets for treatment of H3.3K27M tumors.

The Anti-Atherogenic Properties of Sesamin are Mediated via Improved Macrophage Cholesterol Efflux Through PPARγ1-LXRα and MAPK Signaling

2014 ◽  
Vol 84 (1-2) ◽  
pp. 79-91 ◽  
Author(s):  
Amin F. Majdalawieh ◽  
Hyo-Sung Ro
Keyword(s):  
Cholesterol Efflux ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Foam Cell ◽  
Mapk Signaling ◽  
Luciferase Reporter ◽  
Foam Cell Formation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Macrophage Cholesterol Efflux

Background: Foam cell formation resulting from disrupted macrophage cholesterol efflux, which is triggered by PPARγ1 and LXRα, is a hallmark of atherosclerosis. Sesamin and sesame oil exert anti-atherogenic effects in vivo. However, the exact molecular mechanisms underlying such effects are not fully understood. Aim: This study examines the potential effects of sesamin (0, 25, 50, 75, 100 μM) on PPARγ1 and LXRα expression and transcriptional activity as well as macrophage cholesterol efflux. Methods: PPARγ1 and LXRα expression and transcriptional activity are assessed by luciferase reporter assays. Macrophage cholesterol efflux is evaluated by ApoAI-specific cholesterol efflux assays. Results: The 50 μM, 75 μM, and 100 μM concentrations of sesamin up-regulated the expression of PPARγ1 (p< 0.001, p < 0.001, p < 0.001, respectively) and LXRα (p = 0.002, p < 0.001, p < 0.001, respectively) in a concentration-dependent manner. Moreover, 75 μM and 100 μM concentrations of sesamin led to 5.2-fold (p < 0.001) and 6.0-fold (p<0.001) increases in PPAR transcriptional activity and 3.9-fold (p< 0.001) and 4.2-fold (p < 0.001) increases in LXR transcriptional activity, respectively, in a concentration- and time-dependent manner via MAPK signaling. Consistently, 50 μM, 75 μM, and 100 μM concentrations of sesamin improved macrophage cholesterol efflux by 2.7-fold (p < 0.001), 4.2-fold (p < 0.001), and 4.2-fold (p < 0.001), respectively, via MAPK signaling. Conclusion: Our findings shed light on the molecular mechanism(s) underlying sesamin’s anti-atherogenic effects, which seem to be due, at least in part, to its ability to up-regulate PPARγ1 and LXRα expression and transcriptional activity, improving macrophage cholesterol efflux. We anticipate that sesamin may be used as a therapeutic agent for treating atherosclerosis.

Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation

1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak
Keyword(s):  
Neutrophil Elastase ◽  
Cell Activation ◽  
Thromboxane A2 ◽  
Creatine Phosphate ◽  
Dense Granule ◽  
Cathepsin G ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Low Concentrations ◽  
High Concentrations

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.

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