Staphylococcus aureus, a notorious pathogen with versatile virulence, poses a significant challenge to current antibiotic treatments due to its ability to develop resistance mechanisms against a variety of clinically relevant antibiotics. In this comprehensive review, we carefully dissect the resistance mechanisms employed by S. aureus against various antibiotics commonly used in clinical settings. The article navigates through intricate molecular pathways, elucidating the mechanisms by which S. aureus evades the therapeutic efficacy of antibiotics, such as β-lactams, vancomycin, daptomycin, linezolid, etc. Each antibiotic is scrutinised for its mechanism of action, impact on bacterial physiology, and the corresponding resistance strategies adopted by S. aureus. By synthesising the knowledge surrounding these resistance mechanisms, this review aims to serve as a comprehensive resource that provides a foundation for the development of innovative therapeutic strategies and alternative treatments for S. aureus infections. Understanding the evolving landscape of antibiotic resistance is imperative for devising effective countermeasures in the battle against this formidable pathogen.
- MeSH
- antibakteriální látky * farmakologie terapeutické užití MeSH
- bakteriální léková rezistence MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- stafylokokové infekce * farmakoterapie mikrobiologie MeSH
- Staphylococcus aureus * účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Multidrug resistance is the major obstacle to cancer chemotherapy. Modulation of P-glycoprotein and drug combination approaches have been considered important strategies to overcome drug resistance. PURPOSE: Aiming at generating a small library of Amaryllidaceae-type alkaloids to overcome drug resistance, two major alkaloids, isolated from Pancratium maritimum, lycorine (1), and 2α-10bα-dihydroxy-9-O-demethylhomolycorine (2), were derivatized, giving rise to nineteen derivatives (3 - 21). METHODS: The main chemical transformation of lycorine resulted from the cleavage of ring E of the diacetylated lycorine derivative (3) to obtain compounds that have carbamate and amine functions (5 - 16), while acylation of compound 2 provided derivatives 17 - 21. Compounds 1 - 21 were evaluated for their effects on cytotoxicity, and drug resistance reversal, using resistant human ovarian carcinoma cells (HOC/ADR), overexpressing P-glycoprotein (P-gp/ABCB1), as model. RESULTS: Excluding lycorine (1) (IC50 values of 1.2- 2.5 μM), the compounds were not cytotoxic or showed moderate/weak cytotoxicity. Chemo-sensitization assays were performed by studying the in vitro interaction between the compounds and the anticancer drug doxorubicin. Most of the compounds have shown synergistic interactions with doxorubicin. Compounds 5, 6, 9 - 14, bearing both carbamate and aromatic amine moieties, were found to have the highest sensitization rate, reducing the dose of doxorubicin 5-35 times, highlighting their potential to reverse drug resistance in combination chemotherapy. Selected compounds (4 - 6, 9 - 14, and 21), able of re-sensitizing resistant cancer cells, were further evaluated as P-gp inhibitors. Compound 11, which has a para‐methoxy-N-methylbenzylamine moiety, was the strongest inhibitor. In the ATPase assay, compounds 9-11 and 13 behaved as verapamil, suggesting competitive inhibition of P-gp. At the same time, none of these compounds affected P-gp expression at the mRNA or protein level. CONCLUSIONS: This study provided evidence of the potential of Amaryllidaceae alkaloids as lead candidates for the development of MDR reversal agents.
- MeSH
- adenokarcinom * MeSH
- alkaloidy amarylkovitých * farmakologie MeSH
- alkaloidy * farmakologie MeSH
- chemorezistence MeSH
- doxorubicin farmakologie MeSH
- fenantridiny * MeSH
- karbamáty farmakologie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- P-glykoprotein metabolismus MeSH
- P-glykoproteiny metabolismus MeSH
- protinádorové látky * farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Elevated levels of galectin-3 are associated with tumorigenesis. Its inhibition with high-affinity carbohydrate ligands opens new therapeutic routes. Targeting of intracellular galectin-3 is challenging for polar inhibitors like carbohydrates. We demonstrate the potential of novel biomedical research tools, glycocalix[4]arenes, to enter epithelial cells, which may allow their interaction with galectin-3.
- MeSH
- buněčná membrána MeSH
- galektin 3 * MeSH
- galektiny MeSH
- glykokalyx * MeSH
- sacharidy farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
Cannabidiol (CBD) is the non-psychoactive component of the plant Cannabis sativa (L.) that has great anti-inflammatory benefits and wound healing effects. However, its high lipophilicity, chemical instability, and extensive metabolism impair its bioavailability and clinical use. Here, we report on the preparation of a human cornea substitute in vitro and validate this substitute for the evaluation of drug penetration. CBD nanoemulsion was developed and evaluated for stability and biological activity. The physicochemical properties of CBD nanoemulsion were maintained during storage for 90 days under room conditions. In the scratch assay, nanoformulation showed significantly ameliorated wound closure rates compared to the control and pure CBD. Due to the lower cytotoxicity of nanoformulated CBD, a higher anti-inflammatory activity was demonstrated. Neither nanoemulsion nor pure CBD can penetrate the cornea after the four-hour apical treatment. For nanoemulsion, 94 % of the initial amount of CBD remained in the apical compartment while only 54 % of the original amount of pure CBD was detected in the apical medium, and 7 % in the cornea, the rest was most likely metabolized. In summary, the nanoemulsion developed in this study enhanced the stability and biological activity of CBD.
- MeSH
- antiflogistika farmakologie MeSH
- biologická dostupnost MeSH
- hojení ran MeSH
- kanabidiol * chemie MeSH
- lidé MeSH
- rohovka MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
ETHNOPHARMACOLOGICAL RELEVANCE: Salvia officinalis L., Sambucus nigra L., Matricaria chamomilla L., Agrimonia eupatoria L., Fragaria vesca L. and Malva sylvestris L. are plants that have a long tradition in European folk medicine. To this day, they are part of medicinal teas or creams that help with the healing of skin wounds and the treatment of respiratory or intestinal infections. However, so far these plants have not been investigated more deeply than in their direct antibacterial effect. AIM OF THE STUDY: Our research is focused on adjuvants that inhibit the mechanism of antibiotic resistance or modulate bacterial virulence. Based on a preliminary screening of 52 European herbs, which commonly appear as part of tea blends or poultice. Six of them were selected for their ability to revert the resistant phenotype of nosocomial bacterial strains. METHODS: Herbs selected for this study were obtained from commercially available sources. For the extraction of active compounds ethanol was used. Modulation of virulence was observed as an ability to inhibit bacterial cell-to-cell communication using two mutant sensor strains of Vibrio campbellii. Biofilm formation, and planktonic cell adhesion was measured using a static antibiofilm test. Ethidium bromide assay was used to checked the potential of inhibition bacterial efflux pumps. The antibacterial activities of the herbs were evaluated against resistant bacterial strains using macro dilution methods. RESULTS: Alcohol extracts had antibacterial properties mainly against Gram-positive bacteria. Of all of them, the highest antimicrobial activity demonstrated Malva sylvestris, killing both antibiotic resistant bacteria; Staphylococcus aureus with MIC of 0.8 g/L and Pseudomonas aeruginosa 0.7 g/L, respectively. Fragaria vesca extract (0.08 g/L) demonstrated strong synergism with colistin (4 mg/L) in modulating the resistant phenotype to colistin of Pseudomonas aeruginosa. Similarly, the extract of S. officinalis (0.21 g/L) reverted resistance to gentamicin (1 mg/L) in S. aureus. However, Sambucus nigra and Matricaria chamomilla seem to be a very promising source of bacterial efflux pump inhibitors. CONCLUSION: The extract of F. vesca was the most active. It was able to reduce biofilm formation probably due to the ability to decrease bacterial quorum sensing. On the other hand, the activity of S. nigra or M. chamomilla in reducing bacterial virulence may be explained by the ability to inhibit bacterial efflux systems. All these plants have potential as an adjuvant for the antibiotic treatment.
- MeSH
- antibakteriální látky farmakologie MeSH
- Bacteria MeSH
- biofilmy MeSH
- kolistin farmakologie MeSH
- léčivé rostliny * MeSH
- mikrobiální testy citlivosti MeSH
- Pseudomonas aeruginosa MeSH
- rostlinné extrakty farmakologie MeSH
- Staphylococcus aureus MeSH
- virulence MeSH
- Publikační typ
- časopisecké články MeSH
(1) Background: The detection of DNA double-strand breaks in vitro using the phosphorylated histone biomarker (γH2AX) is an increasingly popular method of measuring in vitro genotoxicity, as it is sensitive, specific and suitable for high-throughput analysis. The γH2AX response is either detected by flow cytometry or microscopy, the latter being more accessible. However, authors sparsely publish details, data, and workflows from overall fluorescence intensity quantification, which hinders the reproducibility. (2) Methods: We used valinomycin as a model genotoxin, two cell lines (HeLa and CHO-K1) and a commercial kit for γH2AX immunofluorescence detection. Bioimage analysis was performed using the open-source software ImageJ. Mean fluorescent values were measured using segmented nuclei from the DAPI channel and the results were expressed as the area-scaled relative fold change in γH2AX fluorescence over the control. Cytotoxicity is expressed as the relative area of the nuclei. We present the workflows, data, and scripts on GitHub. (3) Results: The outputs obtained by an introduced method are in accordance with expected results, i.e., valinomycin was genotoxic and cytotoxic to both cell lines used after 24 h of incubation. (4) Conclusions: The overall fluorescence intensity of γH2AX obtained from bioimage analysis appears to be a promising alternative to flow cytometry. Workflow, data, and script sharing are crucial for further improvement of the bioimage analysis methods.
Sledovat ovlivnění či průběh genové exprese je v mnoha studiích velmi důležitou součástí výzkumu. V současné době dochází k rozvoji mnoha metod usnadňujících sledování regulace genové exprese, jedním z takových příkladů je využití tzv. genových reportérových testů (z angl. gene reporter assays). Tyto systémy představují rozsáhlý soubor nástrojů ke studiu regulačních sekvencí promotorů, zesilovačů a transkripčních faktorů. Existuje celá řada testů využívajících reportérové buňky pro stanovení biologické aktivity studovaných sloučenin. Cílem tohoto přehledového článku je představit přípravu reportérových plasmidů, což je vždy prvním krokem u testů využívajících reportérové geny. Následně budou popsány nejčastější druhy reportérových testů a představeny příklady jejich použití v testování in vitro.
Monitoring the influence or process of gene expression is a very important part of research in many studies. Currently, many methods are being developed to facilitate the monitoring of gene expression regulation, the use of gene reporter assays being one of the examples. These systems represent an extensive set of tools to study the regulatory sequences of promoters, enhancers, and transcription factors. There are several assays using reporter cells to determine the biological activity of the compounds studied. The aim of this review article is to present the preparation of reporter plasmids, which is always the first step in assays using reporter genes. Subsequently, the most common types of reporter test are described, and examples of their use in in vitro testing are presented.
- Publikační typ
- abstrakt z konference MeSH
For the understanding of pathological states of bone tissues in oral surgery, it would be desirable to have the possibility to simulate these processes on bone cell models in vitro. These cultures, similarly to bone tissues, contain numerous proteins entrapped in the insoluble matrix. The major goal of this study was to verify whether a method based on direct in-matrix protein digestion could be suitable for the discrimination between different induced pathological states of bone cell models cultivated in vitro. Using in-sample specific protein digestion with trypsin followed by liquid chromatography-tandem mass spectrometry analysis of released peptides, 446 proteins (in average per sample) were identified in a bone cell in vitro model with induced cancer, 440 proteins were found in a model with induced inflammation, 451 proteins were detected in control in vitro culture, and 491 proteins were distinguished in samples of vestibular laminas of maxillary bone tissues originating from six different patients. Subsequent partial least squares - discrimination analysis of obtained liquid chromatography-tandem mass spectrometry data was able to discriminate among in vitro cultures with induced cancer, with induced inflammation, and control cultivation. Thus, the direct in-sample protein digestion by trypsin followed by liquid chromatography-tandem mass spectrometry analysis of released specific peptide fragments from the insoluble matrix and mathematical analysis of the mass spectrometry data seems to be a promising tool for the routine proteomic characterization of in vitro human bone models with induced different pathological states.
- MeSH
- chromatografie kapalinová metody MeSH
- lidé MeSH
- peptidy analýza MeSH
- proteiny chemie MeSH
- proteolýza MeSH
- proteomika metody MeSH
- stomatochirurgické výkony * MeSH
- tandemová hmotnostní spektrometrie * metody MeSH
- trypsin chemie MeSH
- zánět MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
