RESUMEN
Visceral leishmaniasis (VL) is a severe form of leishmaniasis, primarily affecting the poor in developing countries. Although several studies have highlighted the importance of toll-like receptors (TLRs) in the pathophysiology of leishmaniasis, the role of specific TLRs and their binding partners involved in Leishmania donovani uptake are still elusive. To investigate the mechanism of L. donovani entry inside the macrophages, we found that the parasite lipophosphoglycan (LPG) interacted with the macrophage TLR4, leading to parasite uptake without any significant alteration of macrophage cell viability. Increased parasite numbers within macrophages markedly inhibited lipopolysachharide-induced pro-inflammatory cytokines gene expression. Silencing of macrophage-TLR4, or inhibition of parasite-LPG, significantly stemmed parasite infection in macrophages. Interestingly, we observed a significant enhancement of macrophage migration, and generation of reactive oxygen species (ROS) in the parasite-infected TLR4-silenced macrophages, whereas parasite infection in TLR4-overexpressed macrophages exhibited a notable reduction of macrophage migration and ROS generation. Moreover, mutations in the leucine-rich repeats (LRRs), particularly LRR5 and LRR6, significantly prevented TLR4 interaction with LPG, thus inhibiting cellular parasite entry. All these results suggest that parasite LPG recognition by the LRR5 and LRR6 of macrophage-TLR4 facilitated parasite entry, and impaired macrophage functions. Therefore, targeting LRR5/LRR6 interactions with LPG could provide a novel option to prevent VL.
Asunto(s)
Leishmania donovani , Leishmaniasis Visceral , Parásitos , Animales , Receptor Toll-Like 4 , Especies Reactivas de Oxígeno , MacrófagosRESUMEN
Host-guest complexation-based suprasomes successfully deliver benzimidazolium amphiphiles. ß-CD and Zn2+ or an acidic environment act as the stimuli for the assembly and disassembly of suprasomes. The supramolecular nanomedicine developed by encapsulating tetracycline showed strong and tunable antibacterial activity and holds potential for the next-generation vesicle-based drug delivery system.
Asunto(s)
Antibacterianos , Sistemas de Liberación de Medicamentos , Antibacterianos/farmacologíaRESUMEN
The increasing resistance of bacteria to commercially available antibiotics threatens patient safety in healthcare settings. Perturbation of ion homeostasis has emerged as a potential therapeutic strategy to fight against antibacterial resistance and other channelopathies. This study reports the development of 8-aminoquinoline (QN) derivatives and their transmembrane Zn2+ transport activities. Our findings showed that a potent QN-based Zn2+ transporter exhibits promising antibacterial properties against Gram-positive bacteria with reduced hemolytic activity and cytotoxicity to mammalian cells. Furthermore, this combination showed excellent in vivo efficacy against Staphylococcus aureus. Interestingly, this combination prevented bacterial resistance and restored susceptibility of gentamicin and methicillin-resistant S. aureus to commercially available ß-lactam and other antibiotics that had lost their activity against the drug-resistant bacterial strain. Our findings suggest that the transmembrane transport of Zn2+ by QN derivatives could be a promising strategy to combat bacterial infections and restore the activity of other antibiotics.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Quinolinas , Infecciones Estafilocócicas , Animales , Humanos , Zinc , Ionóforos/uso terapéutico , Tiourea/farmacología , Tiourea/uso terapéutico , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones Estafilocócicas/tratamiento farmacológico , Quinolinas/farmacología , Quinolinas/uso terapéutico , Pruebas de Sensibilidad Microbiana , MamíferosRESUMEN
Increasing evidence supports vanillin and its analogs as potent toll-like receptor signaling inhibitors that strongly attenuate inflammation, though, the underlying molecular mechanism remains elusive. Here, we report that vanillin inhibits lipopolysaccharide (LPS)-induced toll-like receptor 4 activation in macrophages by targeting the myeloid differentiation primary-response gene 88 (MyD88)-dependent pathway through direct interaction and suppression of interleukin-1 receptor-associated kinase 4 (IRAK4) activity. Moreover, incubation of vanillin in cells expressing constitutively active forms of different toll-like receptor 4 signaling molecules revealed that vanillin could only able to block the ligand-independent constitutively activated IRAK4/1 or its upstream molecules-associated NF-κB activation and NF-κB transactivation along with the expression of various proinflammatory cytokines. A significant inhibition of LPS-induced IRAK4/MyD88, IRAK4/IRAK1, and IRAK1/TRAF6 association was evinced in response to vanillin treatment. Furthermore, mutations at Tyr262 and Asp329 residues in IRAK4 or modifications of 3-OMe and 4-OH side groups in vanillin, significantly reduced IRAK4 activity and vanillin function, respectively. Mice pretreated with vanillin followed by LPS challenge markedly impaired LPS-induced IRAK4 activation and inflammation in peritoneal macrophages. Thus, the present study posits vanillin as a novel and potent IRAK4 inhibitor and thus providing an opportunity for its therapeutic application in managing various inflammatory diseases.
Asunto(s)
Lipopolisacáridos , FN-kappa B , Animales , Ratones , Inflamación/metabolismo , Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Lipopolisacáridos/metabolismo , Macrófagos/metabolismo , Factor 88 de Diferenciación Mieloide/metabolismo , FN-kappa B/metabolismo , Receptor Toll-Like 4/metabolismoRESUMEN
Multifunctional drug delivery systems are the centerpiece of effective chemotherapeutic strategies. Herein, we report the synthesis of an acetazolamide-linked cyanine-3-based NIR-responsive fluorescent macrocyclic amphiphile that self-assembled into spherical nanostructures in the aqueous medium via a J-aggregation pattern. The amphiphile shows various favorable properties of lipids. The photocleavage of the strained dioxacycloundecine ring induces spherical to nanotubular self-assembly with concomitant release of an encapsulated anticancer drug, doxorubicin (Dox), in a controlled manner. The CA-IX targeted amphiphile also showed lower cytotoxicity, effective cellular uptake, and Dox delivery to the model carcinoma cells.