RESUMEN
The fading efficacy of antibiotics is a growing global health concern due to its life-threatening consequences and increased healthcare costs. Non-genetic mechanisms of antimicrobial resistance, such as those employed by Chlamydia pneumoniae and Chlamydia trachomatis, complicate treatment as these bacteria can enter a non-replicative, persistent state under stress, evading antibiotics and linking to inflammatory conditions. Understanding chlamydial persistence at the molecular level is challenging, and new models for studying Chlamydia-host interactions in vivo are urgently needed. Caenorhabditis elegans offers an alternative given its immune system and numerous orthologues of human genes. This study established C. elegans as an in vivo model for chlamydial infection. Both Chlamydia species reduced the worm's lifespan, their DNA being detectable at three- and six-days post-infection. Azithromycin at its MIC (25â¯nM) failed to prevent the infection-induced lifespan reduction, indicating a persister phenotype. In contrast, the methanolic extract of Schisandra chinensis berries showed anti-chlamydial activity both in vitro (in THP-1 macrophages) and in vivo, significantly extending the lifespan of infected C. elegans and reducing the bacterial load. Moreover, S. chinensis increased the transcriptional activity of SKN-1 in the worms, but was unable to impact the bacterial load or lifespan in a sek-1 defective C. elegans strain. In summary, this study validated C. elegans as a chlamydial infection model and showcased S. chinensis berries' in vivo anti-chlamydial potential, possibly through SEK/SKN-1 signaling modulation.
Asunto(s)
Antibacterianos , Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Infecciones por Chlamydia , Caenorhabditis elegans/microbiología , Caenorhabditis elegans/efectos de los fármacos , Animales , Humanos , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Infecciones por Chlamydia/microbiología , Infecciones por Chlamydia/tratamiento farmacológico , Antibacterianos/farmacología , Chlamydia trachomatis/efectos de los fármacos , Interacciones Huésped-Patógeno , Extractos Vegetales/farmacología , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Células THP-1 , Azitromicina/farmacología , Longevidad/efectos de los fármacos , Chlamydophila pneumoniae/efectos de los fármacosRESUMEN
This study investigates pharmacy students' reasoning while solving a case task concerning an acute patient counselling situation in a pharmacy. Participants' (N = 34) reasoning processes were investigated with written tasks utilizing eye-tracking in combination with verbal protocols. The case was presented in three pages, each page being followed by written questions. Eye movements were recorded during case processing. Success in the task required differentiating the relevant information from the task redundant information, and initial activation of several scripts and verification of the most likely one, when additional information became available. 2nd (n = 16) and 3rd (n = 18)-year students' and better and worse succeeding students' processes were compared. The results showed that only a few 2nd-year students solved the case correctly, whereas almost all of the 3rd-year students were successful. Generally, the average total processing times of the case material did not differ between the groups. However, better-succeeding and 3rd-year students processed the very first task-relevant sentences longer, indicating that they were able to focus on relevant information. Differences in the written answers to the 2nd and 3rd question were significant, whereas differences regarding the first question were not. Thus, eye-tracking seems to be able to capture illness script activation during case processing, but other methods are needed to depict the script verification process. Based on the results, pedagogical suggestions for advancing pharmacy education are discussed.
Asunto(s)
Movimientos Oculares , Farmacia , Humanos , Evaluación Educacional/métodos , Solución de Problemas , Razonamiento Clínico , Competencia ClínicaRESUMEN
Traditional medicine (TM) is a significant resource for primary healthcare management all over the world, and principally in Africa. Quality improvement activities that promote evidence-based practices and the integration of traditional medicine into primary healthcare systems can help improve the quality of patient care. In the Republic of Benin (West Africa), traditional medicine practitioners (TMPs) provide different treatments and ways of use, depending on the ailments and the medicinal plants used. The present study aimed at documenting the knowledge, attitudes and practices of Beninese TMPs regarding the use of medicinal plants and the challenges associated with their activities. A focus group survey was conducted using semi-structured interviews with a sample of 91 TMPs in 8 departments of the Republic of Benin. The respondents had an average age of 50 years old and belonged to various categories of TMPs. Medicinal plants are harvested depending on the season and time of the day, and are dried in the shade before being used as decoctions or infusions. Nevertheless, the majority of TMPs do not conduct the necessary tests for quality control, efficacy or toxicity of the proposed remedies, which raises several scientific interrogations, particularly for the treatment of mental and brain-related disorders. Among ~ 110 plants used in the treatment of several pathologies, 66 were revealed as threatened species. The challenges faced by TMPs are mainly material, financial and technical difficulties. The present study reports the importance of intervention to modernize TM practices in Benin. Quality improvement could enhance healthcare delivery and provide support for evidence-based interventions aimed at addressing behavioral, social, and environmental determinants of health.
Asunto(s)
Plantas Medicinales , Humanos , Persona de Mediana Edad , Benin , Fitoterapia , Medicinas Tradicionales Africanas , Conocimientos, Actitudes y Práctica en Salud , EncéfaloRESUMEN
Amoxicillin is recommended as primary treatment for community-acquired bacterial pneumonia (CABP). 5-10% of CABP cases are caused by Chlamydia pneumoniae, an obligate intracellular bacterium which responds to beta-lactam antibiotics by converting to a persistent phenotype. To support rational pharmacotherapy of C. pneumoniae infections, we investigated how clinically relevant concentrations of azithromycin and doxycycline affect amoxicillin induced C. pneumoniae persistence. Given the known role of redox state alterations in the action of bactericidal antibiotics and widespread use of redox-active dietary supplements when experiencing respiratory symptoms, we also studied how redox active compounds affect the studied antibiotic treatments. Our data demonstrate that clinically applied amoxicillin concentrations (10 and 25 mg/l) fail to eradicate C. pneumoniae infection in respiratory epithelial cells. Transmission electron microscopy (TEM) of amoxicillin-treated C. pneumoniae infected cells reveal aberrant bacterial morphology characteristic of chlamydial stress response. Amoxicillin was also found to significantly limit the antichlamydial effect of azithromycin or doxycycline. However, based on quantitative culture and quantitative PCR data, azithromycin was superior to doxycycline in C. pneumoniae eradication either as monotherapy or in combination with amoxicillin. Amoxicillin was also found to decrease respiratory epithelial cell glutathione (GSH) levels, whereas redox-active dibenzocyclooctadiene lignans increased C. pneumoniae load in amoxicillin-treated cultures up to two-fold. These data highlight the impact of relative administration time on the efficacy of antichlamydial antibiotics and indicate unfavorable interactions between amoxicillin and redox-active small molecules.
RESUMEN
Medicinal plants play a crucial role in the primary health care of the population in developing countries such as Benin. The national universities of Benin conduct research on the pharmacological, toxicological, and phytochemical properties of these plants, but the resulting knowledge often does not lead to the development of phytomedicines for the improvement of public health. This study aims to assess the current status of research on medicinal plants in Benin. A literature review was conducted using various search engines, and the collected data was analyzed. The results indicate that research on the biological properties of medicinal plants is still in its early stages, with limited and inadequate methodological approaches. These limitations highlight the urgent need to enhance research practices and facilitate the development of effective and safe phytomedicines.
RESUMEN
New classes of antibiotics are urgently needed in the fight against multidrug-resistant bacteria. Drug repurposing has emerged as an alternative approach to accelerate antimicrobial research and development. In this study, we screened a library of sphingosine-1-phosphate receptor (S1PR) modulators against Staphylococcus aureus and identified five active compounds. Among them, etrasimod (APD334), an investigational drug for the treatment of ulcerative colitis, displayed the best inhibitory activity against S. aureus when growing as free-floating planktonic cells and within biofilms. In follow-up studies, etrasimod showed bactericidal activity and drastic reduction of viable bacteria within 1 h of exposure. It also displayed a potent activity against other Gram-positive bacteria, including penicillin- and methicillin-resistant S. aureus strains, S. epidermidis, and Enterococcus faecalis, with a minimum inhibitory concentration (MIC) ranging from 5 to 10 µM (2.3-4.6 µg/mL). However, no inhibition of viability was observed against Gram-negative bacteria Acinetobacter baumannii, Escherichia coli, and Pseudomonas aeruginosa, showing that etrasimod preferably acts against Gram-positive bacteria. On the other hand, etrasimod was shown to inhibit quorum sensing (QS) signaling in Chromobacterium violaceum, suggesting that it may block the biofilm formation by targeting QS in certain Gram-negative bacteria. Furthermore, etrasimod displayed a synergistic effect with gentamicin against S. aureus, thus showing potential to be used in antibiotic combination therapy. Finally, no in vitro toxicity toward mammalian cells was observed. In conclusion, our study reports for the first time the potential of etrasimod as a repurposed antibacterial compound against Gram-positive bacteria.
RESUMEN
Guarana (Paullinia cupana) is a widely consumed nutraceutical with various health benefits supported by scientific evidence. However, its indirect health impacts through the gut microbiota have not been studied. Caenorhabditis elegans is a useful model to study both the direct and indirect effects of nutraceuticals, as the intimate association of the worm with the metabolites produced by Escherichia coli is a prototypic simplified model of our gut microbiota. We prepared an ethanoic extract of guarana seeds and assessed its antioxidant capacity in vitro, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and in vivo, utilizing C. elegans. Additionally, we studied the impact of this extract on C. elegans lifespan, utilizing both viable and non-viable E. coli, and assessed the impact of guarana on E. coli folate production. The extract showed high antioxidant capacity, and it extended worm lifespan. However, the antioxidant and life-extending effects did not correlate in terms of the extract concentration. The extract-induced life extension was also less significant when utilizing dead E. coli, which may indicate that the effects of guarana on the worms work partly through modifications on E. coli metabolism. Following this observation, guarana was found to decrease E. coli folate production, revealing one possible route for its beneficial effects.
Asunto(s)
Paullinia , Animales , Antioxidantes/farmacología , Caenorhabditis elegans , Escherichia coli , Ácido Fólico/farmacología , Longevidad , Paullinia/química , Extractos Vegetales/farmacologíaRESUMEN
The obligate intracellular bacterium, Chlamydia pneumoniae, has been identified as a risk factor for several chronic inflammatory diseases in addition to respiratory tract infections. The dissemination of C. pneumoniae from respiratory tract to secondary sites of infection occurs via infected monocyte / macrophage line cells, in which C. pneumoniae can persist as an antibiotic-refractory phenotype. To allow more detailed studies on the epithelium-monocyte/macrophage transition of the infection, new in vitro bioassays are needed. To this end, a coculture system with human continuous cell lines was established. Respiratory epithelial HL cells were infected with C. pneumoniae and THP-1 monocytes were added into the cultures at 67 h post infection. After a 5 h coculture, THP-1 cells were collected with a biotinylated HLA antibody and streptavidin-coated magnetic beads and C. pneumoniae genome copy numbers in THP-1 determined by quantitative PCR. The assay was optimized for cell densities, incubation time, THP-1 separation technique and buffer composition, and its robustness was demonstrated by a Z' value of 0.6. The mitogen-activated protein kinase (MAPK) inhibitors: SP600125 (JNK inhibitor), SB203580 (p38 inhibitor) and FR180204 (ERK inhibitor) suppressed the transfer of C. pneumoniae from HL to THP-1 cells, making them suitable positive controls for the assay. Based on analysis of separate steps of the process, the MAPK inhibitors suppress the bacterial entry to THP-1 cells. The transfer of C. pneumoniae from epithelium to phagocytes represents a crucial step in the establishment of persistent infections by this pathogen, and the presented methods enables future studies to block this process by therapeutic means.
Asunto(s)
Infecciones por Chlamydophila/patología , Infecciones por Chlamydophila/transmisión , Células Epiteliales/microbiología , Macrófagos/microbiología , Monocitos/microbiología , Antracenos/farmacología , Línea Celular , Chlamydophila pneumoniae/patogenicidad , Técnicas de Cocultivo , Epitelio/microbiología , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Humanos , Imidazoles/farmacología , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Reacción en Cadena de la Polimerasa/métodos , Pirazoles , Piridazinas , Piridinas/farmacología , Células THP-1 , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidoresRESUMEN
Antibiotic-tolerant persister bacteria involve frequent treatment failures, relapsing infections and the need for extended antibiotic treatment. The virulence of an intracellular human pathogen C. pneumoniae is tightly linked to its propensity for persistence and means for its chemosensitization are urgently needed. In the current work, persistence of C. pneumoniae clinical isolate CV6 was studied in THP-1 macrophages using quantitative PCR and quantitative culture. A dibenzocyclooctadiene lignan schisandrin reverted C. pneumoniae persistence and promoted productive infection. The concomitant administration of schisandrin and azithromycin resulted in significantly improved bacterial eradication compared to sole azithromycin treatment. In addition, the closely related lignan schisandrin C was superior to azithromycin in eradicating the C. pneumoniae infection from the macrophages. The observed chemosensitization of C. pneumoniae was associated with the suppression of cellular glutathione pools by the lignans, implying to a previously unknown aspect of chlamydia-host interactions. These data indicate that schisandrin lignans induce a phenotypic switch in C. pneumoniae, promoting the productive and antibiotic-susceptible phenotype instead of persistence. By this means, these medicinal plant -derived compounds show potential as adjuvant therapies for intracellular bacteria resuscitation.
Asunto(s)
Bioensayo/métodos , Chlamydophila pneumoniae/fisiología , Ciclooctanos/farmacología , Lignanos/farmacología , Macrófagos/microbiología , Azitromicina/administración & dosificación , Azitromicina/farmacología , Chlamydophila pneumoniae/efectos de los fármacos , Chlamydophila pneumoniae/crecimiento & desarrollo , Ciclooctanos/administración & dosificación , Ciclooctanos/química , Glutatión/metabolismo , Humanos , Cinética , Lignanos/administración & dosificación , Lignanos/química , Macrófagos/efectos de los fármacos , Oxidación-Reducción , Fenotipo , Compuestos Policíclicos/administración & dosificación , Compuestos Policíclicos/química , Compuestos Policíclicos/farmacología , Especies Reactivas de Oxígeno/metabolismo , Células THP-1RESUMEN
The present study investigated Staphylococcus aureus ATCC25923 surfaceomes (cell surface proteins) during prolonged growth by subjecting planktonic and biofilm cultures (initiated from exponential or stationary cells) to label-free quantitative surfaceomics and phenotypic confirmations. The abundance of adhesion, autolytic, hemolytic, and lipolytic proteins decreased over time in both growth modes, while an opposite trend was detected for many tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) scavenging, Fe-S repair, and peptidolytic moonlighters. In planktonic cells, these changes were accompanied by decreasing and increasing adherence to hydrophobic surface and fibronectin, respectively. Specific RNA/DNA binding (cold-shock protein CspD and ribosomal proteins) and the immune evasion (SpA, ClfA, and IsaB) proteins were notably more abundant on fully mature biofilms initiated with stationary-phase cells (SDBF) compared to biofilms derived from exponential cells (EDBF) or equivalent planktonic cells. The fully matured SDBF cells demonstrated higher viability in THP-1 monocyte/macrophage cells compared to the EDBF cells. Peptidoglycan strengthening, specific urea-cycle, and detoxification enzymes were more abundant on planktonic than biofilm cells, indicating the activation of growth-mode specific pathways during prolonged cultivation. Thus, we show that S. aureus shapes its surfaceome in a growth mode-dependent manner to reach high levofloxacin tolerance (>200-times the minimum biofilm inhibitory concentration). This study also demonstrates that the phenotypic state of the cells prior to biofilm formation affects the immune-evasion and persistence-related traits of S. aureus.
RESUMEN
Redox signaling has been established as an essential component of inflammatory responses, and redox active compounds are of interest as potential immunomodulatory agents. Dibenzocyclooctadiene lignans isolated from Schisandra chinensis, a medicinal plant with widespread use in oriental medicine, have been implicated to possess immunomodulatory properties but their effects on the human innate immune system cells have not been described. In this contribution, data are presented on the impact of schisandrin, schisandrin B and schisandrin C on human monocytic cell redox status, as well as their impact on dendritic cell maturation and T cell activation capacity and cytokine production. In THP-1 cells, levels of intracellular reactive oxygen species (ROS) were elevated after 1â¯h exposure to schisandrin. Schisandrin B and schisandrin C decreased cellular glutathione pools, which is a phenotype previously reported to promote anti-inflammatory functions. Treatment of human primary monocytes with the lignans during their maturation to dendritic cells did not have any effect on the appearance of surface markers HLA-DR and CD86 but schisandrin B and schisandrin C suppressed the secretion of cytokines interleukin (IL)-6, IL-10 and IL-12 by the mature dendritic cells. Dendritic cells maturated in presence of schisandrin C were further cocultured with naïve CD4+â¯T cells, resulting in reduced IL-12 production. In THP-1 cells, schisandrin B and schisandrin C reduced the IL-6 and IL-12 production triggered by E. coli lipopolysaccharide and IL-12 production induced by an infection with Chlamydia pneumoniae. In conclusion, the studied lignans act as immunomodulatory agents by altering the cytokine secretion, but do not interfere with dendritic cell maturation. And the observed effects may be associated with the ability of the lignans to alter cellular redox status.
Asunto(s)
Ciclooctanos/farmacología , Células Dendríticas/efectos de los fármacos , Factores Inmunológicos/farmacología , Lignanos/farmacología , Compuestos Policíclicos/farmacología , Linfocitos T/efectos de los fármacos , Antígeno B7-2/genética , Antígeno B7-2/inmunología , Chlamydophila pneumoniae/crecimiento & desarrollo , Técnicas de Cocultivo , Ciclooctanos/aislamiento & purificación , Células Dendríticas/inmunología , Expresión Génica/efectos de los fármacos , Glutatión/inmunología , Glutatión/metabolismo , Antígenos HLA-DR/genética , Antígenos HLA-DR/inmunología , Humanos , Factores Inmunológicos/aislamiento & purificación , Interleucina-10/genética , Interleucina-10/inmunología , Interleucina-12/genética , Interleucina-12/inmunología , Interleucina-6/genética , Interleucina-6/inmunología , Lignanos/aislamiento & purificación , Lipopolisacáridos/farmacología , Activación de Linfocitos/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Compuestos Policíclicos/aislamiento & purificación , Cultivo Primario de Células , Especies Reactivas de Oxígeno/inmunología , Especies Reactivas de Oxígeno/metabolismo , Schisandra/química , Linfocitos T/inmunología , Linfocitos T/microbiología , Células THP-1RESUMEN
The obligate intracellular pathogen Chlamydia pneumoniae remains a difficult target for antimicrobial therapy. Owing to the permeability barrier placed by bacterial and host vacuolar membranes, as well as the propensity of the bacterium for persistent infections, treatment failures are common. Despite the urgent need for new antichlamydial compounds, their discovery is challenged by the technically demanding assay procedures and lack of validated targets. An alternative strategy of using naturally occurring compounds and their derivatives against C. pneumoniae is presented. The strategy consists of the application of ligand-based virtual screening to a natural product library of 502 compounds with the ChemGPS-NP chemography tool followed by in vitro antichlamydial assays. The reference set used for the 2D similarity search was constructed of 19 known antichlamydial compounds of plant origin. Based on the similarity screen, 53 virtual hits were selected for in vitro testing. Six compounds (leads) were identified that cause ≥50% C. pneumoniae growth inhibition and showed no impact on host cell viability. The leads fall into completely new antichlamydial chemotypes, one of them being mycophenolic acid (IC50 value 0.3 µM). The outcome indicates that using this flipped, target-independent strategy is useful for facilitating the antimicrobial lead discovery against challenging microbes.
Asunto(s)
Antibacterianos/farmacología , Productos Biológicos/farmacología , Chlamydophila pneumoniae/efectos de los fármacos , Antibacterianos/química , Azitromicina/farmacología , Productos Biológicos/química , Línea Celular , Supervivencia Celular/efectos de los fármacos , Descubrimiento de Drogas , Humanos , Ligandos , Pruebas de Sensibilidad Microbiana , Estructura MolecularRESUMEN
Acquired therapeutic resistance by tumors is a substantial impediment to reducing the morbidity and mortality that are attributable to human malignancies. The mechanisms responsible for the dramatic shift between chemosensitivity and chemoresistance in colorectal carcinoma have not been defined. Here, we report that LRP16 selectively interacts and activates double-stranded RNA-dependent kinase (PKR), and also acts as scaffolds to assist the formation of a ternary complex of PKR and IKKß, prolonging the polymers of ADP-ribose (PAR)-dependent nuclear factor kappa B (NF-κB) transactivation caused by DNA-damaging agents and confers acquired chemoresistance. We also identified a small molecule, MRS2578, which strikingly abrogated the binding of LRP16 to PKR and IKKß, converting LRP16 into a death molecule and forestalling colon tumorigenesis. Inclusion of MRS2578 with etoposide, versus each drug alone, exhibited synergistic antitumor cytotoxicity in xenografts. Our combinatorial approach introduces a strategy to enhance the efficacy of genotoxicity therapies for the treatment of tumors.
Most chemotherapy drugs kill cancer cells by damaging their DNA. The cells have systems to combat this damage and help them to survive, and in some cells these systems work effectively enough to make the cancer effectively resistant to the treatment. For example, a protein called NF-κB can turn on various genes that help to repair damaged DNA. However, DNA is contained the cell nucleus, whereas the inactive form of NF-κB is found outside the cell nucleus. So how does the damaged DNA communicate with and activate NF-κB? Previous research had found that another protein called LRP16, which resides in the cell nucleus, plays a crucial role in the repair process that NF-κB is involved in. Li, Wu, An et al. have now studied bowel cancer cells taken from human tissue samples and found that the cancerous cells contained higher levels of LRP16 than cells from the surrounding tissue. Patients with cancers containing very high levels of LRP16 were more severely affected by cancer. Further investigation revealed that when DNA is damaged, LRP16 moves out of the cell nucleus and stabilises how NF-κB interacts with two other proteins; this stabilisation activates NF-κB. LRP16 therefore appears to regulate the signal that travels out of the nucleus from the damaged DNA to activate NF-κB. Further experiments showed that anti-cancer treatments worked best on cancer cells that lacked LRP16. Thus it appears that LRP16 helps cancer cells to respond to and resist the DNA damage caused by chemotherapy. Li, Wu, An et al. went on to identify a drug that prevented the activation of NF-κB by blocking the effects of LRP16. Using this drug alongside chemotherapy drugs made the cells more likely to self-destruct. More work is now needed to develop therapies based on the newly identified drug and to establish how DNA damage activates LRP16.
Asunto(s)
Antineoplásicos/administración & dosificación , Neoplasias Colorrectales/tratamiento farmacológico , ADN/metabolismo , Isotiocianatos/metabolismo , FN-kappa B/antagonistas & inhibidores , Proteínas de Neoplasias/antagonistas & inhibidores , Tiourea/análogos & derivados , eIF-2 Quinasa/antagonistas & inhibidores , Animales , Hidrolasas de Éster Carboxílico , Línea Celular Tumoral , Modelos Animales de Enfermedad , Sinergismo Farmacológico , Inhibidores Enzimáticos/administración & dosificación , Etopósido/administración & dosificación , Xenoinjertos , Humanos , Quinasa I-kappa B/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Trasplante de Neoplasias , Unión Proteica , Transducción de Señal , Tiourea/metabolismo , Resultado del TratamientoRESUMEN
Throughout its known history, the gram-negative bacterium Chlamydia pneumoniae has remained a challenging target for antibacterial chemotherapy and drug discovery. Owing to its well-known propensity for persistence and recent reports on antimicrobial resistence within closely related species, new approaches for targeting this ubiquitous human pathogen are urgently needed. In this review, we describe the strategies that have been successfully applied for the identification of nonconventional antichlamydial agents, including target-based and ligand-based virtual screening, ethnopharmacological approach and pharmacophore-based design of antimicrobial peptide-mimicking compounds. Among the antichlamydial agents identified via these strategies, most translational work has been carried out with plant phenolics. Thus, currently available data on their properties as antichlamydial agents are described, highlighting their potential mechanisms of action. In this context, the role of mitogen-activated protein kinase activation in the intracellular growth and survival of C. pneumoniae is discussed. Owing to the complex and often complementary pathways applied by C. pneumoniae in the different stages of its life cycle, multitargeted therapy approaches are expected to provide better tools for antichlamydial therapy than agents with a single molecular target.
RESUMEN
We demonstrate in the current work that small cationic antimicrobial ß2,2-amino acid derivatives (Mw < 500 Da) are highly potent against Chlamydia pneumoniae at clinical relevant concentrations (< 5 µM, i.e. < 3.4 µg/mL). C. pneumoniae is an atypical respiratory pathogen associated with frequent treatment failures and persistent infections. This gram-negative bacterium has a biphasic life cycle as infectious elementary bodies and proliferating reticulate bodies, and efficient treatment is challenging because of its long and obligate intracellular replication cycle within specialized inclusion vacuoles. Chlamydicidal effect of the ß2,2-amino acid derivatives in infected human epithelial cells was confirmed by transmission electron microscopy. Images of infected host cells treated with our lead derivative A2 revealed affected chlamydial inclusion vacuoles 24 hours post infection. Only remnants of elementary and reticulate bodies were detected at later time points. Neither the EM studies nor resazurin-based cell viability assays showed toxic effects on uninfected host cells or cell organelles after A2 treatment. Besides the effects on early intracellular inclusion vacuoles, the ability of these ß2,2-amino acid derivatives to suppress Chlamydia pneumoniae infectivity upon treatment of elementary bodies suggested also a direct interaction with bacterial membranes. Synthetic ß2,2-amino acid derivatives that target C. pneumoniae represent promising lead molecules for development of antimicrobial agents against this hard-to-treat intracellular pathogen.
Asunto(s)
Aminoácidos de Cadena Ramificada , Ciclo Celular/efectos de los fármacos , Infecciones por Chlamydophila/tratamiento farmacológico , Chlamydophila pneumoniae/crecimiento & desarrollo , Aminoácidos de Cadena Ramificada/síntesis química , Aminoácidos de Cadena Ramificada/química , Aminoácidos de Cadena Ramificada/farmacología , Línea Celular , Infecciones por Chlamydophila/metabolismo , Infecciones por Chlamydophila/patología , Chlamydophila pneumoniae/citología , Chlamydophila pneumoniae/patogenicidad , HumanosRESUMEN
Chikungunya virus (CHIKV) is an arthritogenic arbovirus of the Alphavirus genus, which has infected millions of people after its re-emergence in the last decade. In this study, a BHK cell line containing a stable CHIKV replicon with a luciferase reporter was used in a high-throughput platform to screen approximately 3000 compounds. Following initial validation, 25 compounds were chosen as primary hits for secondary validation with wild type and reporter CHIKV infection, which identified three promising compounds. Abamectin (EC50 = 1.5 µM) and ivermectin (EC50 = 0.6 µM) are fermentation products generated by a soil dwelling actinomycete, Streptomyces avermitilis, whereas berberine (EC50 = 1.8 µM) is a plant-derived isoquinoline alkaloid. They inhibited CHIKV replication in a dose-dependent manner and had broad antiviral activity against other alphaviruses--Semliki Forest virus and Sindbis virus. Abamectin and ivermectin were also active against yellow fever virus, a flavivirus. These compounds caused reduced synthesis of CHIKV genomic and antigenomic viral RNA as well as downregulation of viral protein expression. Time of addition experiments also suggested that they act on the replication phase of the viral infectious cycle.
Asunto(s)
Alphavirus/efectos de los fármacos , Antivirales/farmacología , Fiebre Chikungunya/tratamiento farmacológico , Virus Chikungunya/efectos de los fármacos , Alphavirus/fisiología , Animales , Berberina/farmacología , Línea Celular , Línea Celular Tumoral , Fiebre Chikungunya/virología , Virus Chikungunya/fisiología , Cricetinae , ADN Viral/antagonistas & inhibidores , ADN Viral/biosíntesis , ADN Viral/efectos de los fármacos , Flavivirus/efectos de los fármacos , Humanos , Ivermectina/análogos & derivados , Ivermectina/farmacología , ARN Viral/antagonistas & inhibidores , ARN Viral/biosíntesis , ARN Viral/efectos de los fármacos , ARN Viral/genética , Replicón/efectos de los fármacos , Proteínas Virales/antagonistas & inhibidores , Proteínas Virales/biosíntesis , Proteínas Virales/efectos de los fármacos , Replicación Viral/efectos de los fármacos , Virus de la Fiebre Amarilla/efectos de los fármacosRESUMEN
The impact of solvent extracts from the distillation water (flavoring extracts) isolated from mint flavored candies on the infectivity of the intracellular bacterium Chlamydia pneumoniae was evaluated by an in vitro model of epithelial cell infections., The mint flavoring extracts were isolated from the candies by simultaneous hydrodistillation and their chemical composition, established by GC-MS, demonstrated menthol and limonene as the most abundant components. Results obtained by treating C. pneumoniae elementary bodies (EBs) with the flavoring extracts or pure reference compounds showed a significant decrease in EB infectivity, achieved with most of the extracts. This antichlamydial activity could be related to the relatively high menthol content of the extracts. Overall, the obtained data indicates that the flavorings present in the candies are able to target the metabolically quiet, non-replicating form of the bacterium and to suppress the spread of this respiratory pathogen from one cell to another.
Asunto(s)
Dulces/análisis , Chlamydophila pneumoniae/efectos de los fármacos , Aromatizantes/farmacología , Mentha/química , Línea Celular , Supervivencia Celular/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Aromatizantes/química , HumanosRESUMEN
The purpose of this study was to investigate the effect and selectivity of an extract of Schisandra chinensis berries against Chlamydia pneumoniae and C. trachomatis. Among the ethnopharmacological uses of the extract from Schisandrae fructus are cough and pneumonia. Therefore we focused on respiratory pathogens. The extract completely inhibited the growth of C. pneumoniae strain CV6 at 250 µg/mL concentration. The inhibition of C. pneumoniae and C. trachomatis growth was dose dependent and established with three different strains. The extract inhibited C. pneumoniae production of infectious progeny in a dose dependent manner. Chlamydia selectivity was elucidated with growth inhibition measurements of three other respiratory bacterial species. A pure compound found in Schisandra chinensis berries, schisandrin B at 20.0 µg/mL concentration inhibited the growth of both C. pneumoniae and C. trachomatis. The extract was found to be non-toxic to the human host cells. These findings highlight the potential of the extract from Schisandra chinensis berries as a source for antichlamydial compounds.
Asunto(s)
Chlamydia/efectos de los fármacos , Lignanos/química , Lignanos/farmacología , Extractos Vegetales/farmacología , Schisandra/química , Chlamydia/crecimiento & desarrollo , Infecciones por Chlamydia/microbiología , Frutas/química , Células HeLa , Humanos , Extractos Vegetales/químicaRESUMEN
Lignans from Schisandra chinensis berries show various pharmacological activities, of which their antioxidative and cytoprotective properties are among the most studied ones. Here, the first report on antibacterial properties of six dibenzocyclooctadiene lignans found in Schisandra spp. is presented. The activity was shown on two related intracellular Gram-negative bacteria Chlamydia pneumoniae and Chlamydia trachomatis upon their infection in human epithelial cells. All six lignans inhibited C. pneumoniae inclusion formation and infectious progeny production. Schisandrin B inhibited C. pneumoniae inclusion formation even when administered 8 h post infection, indicating a target that occurs relatively late within the infection cycle. Upon infection, lignan-pretreated C. pneumoniae elementary bodies had impaired inclusion formation capacity. The presence and substitution pattern of methylenedioxy, methoxy and hydroxyl groups of the lignans had a profound impact on the antichlamydial activity. In addition our data suggest that the antichlamydial activity is not caused only by the antioxidative properties of the lignans. None of the compounds showed inhibition on seven other bacteria, suggesting a degree of selectivity of the antibacterial effect. Taken together, the data presented support a role of the studied lignans as interesting antichlamydial lead compounds.