RESUMEN
Staphylococcus aureus (S. aureus), an important opportunistic pathogen in human and animal, causes a series of diseases in the impairing of immunity of host and even then death. Alpha-hemolysin (Hla), a primary virulence factor, plays a major role in the pathogenic progress of S. aureus, especially in pneumonia. Prim-O-glucosylcimifugin (POG), a nature chromone compound, is an active ingredient in many Chinese Medicines. In this study, POG investigated the inhibitory effect of the secretion of Hla in S. aureus strain USA300 at the subinhibitory concentrations. The hemolysis assays and western blotting assays showed that POG can decrease the production of Hla in the USA300 growth cell cultures in a dose-dependent manner. The results of RT-PCR revealed that reduction of Hla was related to inhibit the transcription of hla and RNAIII. In the cells experiment, POG was proved to protect A549 cells from Hla-medicated injury. In conclusion, POG was shown the capacity of decreased the production of S. aureus Hla. POG can be developed as a candidate agent to treat S. aureus infections against Hla.
RESUMEN
Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that causes various diseases in both humans and animals. With the increased prevalence of methicillin-resistant S. aureus, the therapeutic effects of commonly used antibiotics are limited against S. aureus infection. Novel treatment strategies and new antibiotics are needed urgently to address this concern. Many studies have shown that virulence factors secreted from S. aureus play vital roles in their pathogenic processes. Alpha-hemolysin (Hla), an important exotoxin in S. aureus, is one such virulence factor that increases sensitivity of multiple host cells to S. aureus resulting in various diseases. Eriodictyol is a flavonoid compound that exists in many fruits and vegetables. In this study, eriodictyol was demonstrated to inhibit the expression of Hla by hemolysis assays, western blotting, and RT-qPCR at the sub-minimal inhibitory concentration. In live/dead and cytotoxicity assays, the results showed that eriodictyol protected A549 cells against Hla-induced injury in a dose-dependent manner. The minimal inhibitory concentration of eriodictyol against S. aureus was 512 µg/mL. Eriodictyol can downregulate S. aureus Hla at both the expressional and transcriptional levels without affecting S. aureus growth. In addition, cell assays had proved that eriodictyol could protect A549 cells against Hla damage. Eriodictyol could therefore have the potential to treat S. aureus infection targeting Hla.
Asunto(s)
Antibacterianos/farmacología , Toxinas Bacterianas/toxicidad , Flavanonas/farmacología , Proteínas Hemolisinas/efectos de los fármacos , Proteínas Hemolisinas/toxicidad , Lesión Pulmonar/prevención & control , Staphylococcus aureus/efectos de los fármacos , Células A549/efectos de los fármacos , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Hemólisis , Humanos , Lesión Pulmonar/microbiología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/metabolismo , Pruebas de Sensibilidad Microbiana , Neumonía Estafilocócica/microbiología , Neumonía Estafilocócica/patología , Neumonía Estafilocócica/prevención & control , Staphylococcus aureus/crecimiento & desarrollo , Staphylococcus aureus/metabolismo , Staphylococcus aureus/patogenicidad , Factores de Virulencia/metabolismoRESUMEN
Staphylococcus aureus (S. aureus) is a common gram-positive bacterium that causes serious infections in humans and animals. With the continuous emergence of methicillin-resistant S. aureus (MRSA) strains, antibiotics have limited efficacy in treating MRSA infections. Accordingly, novel agents that act on new targets are desperately needed to combat these infections. S. aureus alpha-hemolysin plays an indispensable role in its pathogenicity. In this study, we demonstrate that sclareol, a fragrant chemical compound found in clary sage, can prominently decrease alpha-hemolysin secretion in S. aureus strain USA300 at sub-inhibitory concentrations. Hemolysis assays, western-blotting, and RT-PCR were used to detect the production of alpha-hemolysin in the culture supernatant. When USA300 was co-cultured with A549 epithelial cells, sclareol could protect the A549 cells at a final concentration of 8 µg/ml. The protective capability of sclareol against the USA300-mediated injury of A549 cells was further shown by cytotoxicity assays and live/dead analysis. In conclusion, sclareol was shown to inhibit the production of S. aureus alpha-hemolysin. Sclareol has potential for development as a new agent to treat S. aureus infections.
RESUMEN
To study the anticoagulant effect of Xiang-Qi-Tang (XQT),the mice model of endotoxemia was established to detect the expression of coagulation factors and their regulatory proteins in serum and aorta.The results showed that XQT could decrease the expression of TF and increase the expression of tPA in the aorta of mice with endotoxemia,and also decrease the expression of sEPCR in the serum.We further found that XQT caused the decrease of sEPCR through the regulation of PKC δ and ADAM17 to contribute the anticoagulation in mice.This study may provide a new strategy for treating endotoxin-induced disease and provide evidences for further researching the pharmacological action of XQT.