Inhibition of alpha-hemolysin expression by resveratrol attenuates Staphylococcus aureus virulence

Tang, Feng; Li, Li; Meng, Xian-Mei; Li, Bing; Wang, Chun-Qiang; Wang, Shuquan; Tian, Yuan

doi:10.1016/j.micpath.2018.11.027

Cited by 52 publications

(21 citation statements)

References 32 publications

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“…AIP, a signaling molecule of the agr system, is responsible for upregulating the expression of exoproteins, including hla-encoded α-hemolysin (Queck et al 2008;Shoham 2011). Resveratrol inhibits Hla expression when cultured with S. aureus by reducing the transcription of hla as well as RNAIII (Tang et al 2019). According to previous results and the data presented here, we speculate that AS inhibits toxin synthesis by inhibiting the agr system and that the decrease in toxin synthesis leads to a decrease in biofilmforming ability.…”

Section: Discussionsupporting

confidence: 80%

Artesunate inhibits Staphylococcus aureus biofilm formation by reducing alpha-toxin synthesis

Yan

Lai

et al. 2020

Arch Microbiol

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Staphylococcus aureus is one of the most common pathogens in bacterial biofilm infections. Antibiotic treatment for infection caused by S. aureus biofilms is challenging, and few effective strategies have been developed to combat these infections. The aim of this study was to investigate the effect and possible mechanisms of artesunate on the biofilm formation of S. aureus. Bacterial growth curves were determined by a microtiter plate. Biofilm formation was determined by the crystal violet staining method and confocal laser scanning microscopy. Bacterial adhesion was assayed by the colony-counting method. The expression of virulence and adhesion genes was determined by real-time PCR. The hemolytic activity and expression of ɑ-hemolysin were analyzed using rabbit erythrocytes and Western blotting. The results showed that artesunate could significantly inhibit the biofilm formation of S. aureus in a dose-dependent manner. Artesunate could also inhibit bacterial adhesion and the expression of hla, RNAIII and agrA as well as ɑ-hemolysin production. The effect of artesunate on adhesion genes (clfA, clfB, fnbA, fnbB) had strain specificity, but it did not affect the expression of ica genes. The results indicated that artesunate might inhibit ɑ-hemolysin synthesis by the agr system, which inhibits biofilm formation.

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Section: Discussionsupporting

confidence: 80%

Artesunate inhibits Staphylococcus aureus biofilm formation by reducing alpha-toxin synthesis

Yan

Lai

et al. 2020

Arch Microbiol

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“…However, RES suffers from rapid metabolism and low bioavailability when given orally, therefore, various nano-formulations have been proposed as means to overcome RES limitations as therapeutic agents [6]. Interestingly, very recent publication by Tang and colleagues claims that RES acts as an effective alpha-hemolysin (Hla) inhibitor that reduces Hla expression without antimicrobial activity and could serve as a potent agent against Staphylococcus aureus infections [8]. On the other hand, most of the polyphenols present in green tea are flavanols, commonly known as catechins.…”

Section: Introductionmentioning

confidence: 99%

Localized Therapy of Vaginal Infections and Inflammation: Liposomes-In-Hydrogel Delivery System for Polyphenols

et al. 2019

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Natural polyphenols, such as resveratrol (RES) or epicatechin (EPI), are attractive for treatments of various diseases, including vaginal infections and inflammation, because of their strong anti-oxidative and anti-inflammatory properties. However, their low solubility and consequent poor bioavailability limit their therapeutic uses. To overcome these limitations, a vaginal delivery system comprising either RES or EPI liposomes-in-hydrogel was developed. This system permits therapeutic action of both liposomal polyphenol (RES or EPI) and chitosan-based hydrogel. Liposomes of around 200 nm and entrapment efficiency of 81% and 77% for RES and EPI, respectively, were incorporated into chitosan hydrogel, respectively. Medium molecular weight chitosan (2.5%, w/w) was found to have optimal texture properties and mucoadhesiveness in ex vivo conditions. The in vitro release studies confirmed the sustained release of polyphenols from the system. Both liposomal polyphenols and polyphenols-in-liposomes-in-hydrogel exhibited only minor effects on cell toxicity. EPI showed superior radical scavenging activity at lower concentrations compared to antioxidants vitamin C and E. Anti-inflammatory activity expressed as the inhibitory activity of formulations on the NO production in the LPS-induced macrophages (RAW 264.7) confirmed the superiority of EPI liposomes-in-hydrogel. The plain liposomes-in-hydrogel also exhibited potent anti-inflammatory activity, suggesting that chitosan hydrogel acts in synergy regarding anti-inflammatory effect of formulation.

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“…The antibacterial activity of polyphenols is realized at the level of whole bacteria through the damage (modification) of the membrane structure [5][6][7] and via inhibition of energy metabolism 8 , production or secretion of toxins [9][10][11][12] , as well as by prevention of biofilm formation 13,14 (Fig. 1).…”

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confidence: 99%

Inhibition of interaction between Staphylococcus aureus α-hemolysin and erythrocytes membrane by hydrolysable tannins: structure-related activity study

Olchowik-Grabarek

Sękowski

Bitiucki

et al. 2020

Sci Rep

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The objective of the study was a comparative analysis of the antihemolytic activity against two Staphylococcus aureus strains (8325-4 and NCTC 5655) as well as α-hemolysin and of the membrane modifying action of four hydrolysable tannins with different molecular mass and flexibility: 3,6-bis-O-di-O-galloyl-1,2,4-triO -galloyl-β-d-glucose (T1), 1,2,3,4,5-penta-O-galloyl-β-d-glucose (T2), 3-O-galloyl-1,2-valoneoyl-β-d-glucose (T3) and 1,2-di-O-galloyl-4,6-valoneoyl-β-d-glucose (T4). We showed that all the compounds studied manifested antihemolytic effects in the range of 5-50 µM concentrations. However, the degree of the reduction of hemolysis by the investigated tannins was not uniform. A valoneoyl group-containing compounds (T3 and T4) were less active. Inhibition of the hemolysis induced by α-hemolysin was also noticed on preincubated with the tannins and subsequently washed erythrocytes. In this case the efficiency again depended on the tannin structure and could be represented by the following order: T1 > T2 > T4 > T3. We also found a relationship between the degree of antihemolytic activity of the tannins studied and their capacity to increase the ordering parameter of the erythrocyte membrane outer layer and to change zeta potential. Overall, our study showed a potential of the T1 and T2 tannins as anti-virulence agents. The results of this study using tannins with different combinations of molecular mass and flexibility shed additional light on the role of tannin structure in activity manifestation. Over the past few years, a significant increase in bacterial resistance to antibiotics and transference of resistance genes from animal to human strains has become a global medical problem. Therefore, constant search for new antimicrobial agents among them being compounds of plant origin, including polyphenols, is ongoing 1,2. In addition to the antibiotic approaches of combating bacteria, anti-virulence strategies have also been considered recently. An anti-virulent strategy assumes a direct effect of compounds on virulent factors by reducing

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Inhibition of alpha-hemolysin expression by resveratrol attenuates Staphylococcus aureus virulence

Cited by 52 publications

References 32 publications

Artesunate inhibits Staphylococcus aureus biofilm formation by reducing alpha-toxin synthesis

Artesunate inhibits Staphylococcus aureus biofilm formation by reducing alpha-toxin synthesis

Localized Therapy of Vaginal Infections and Inflammation: Liposomes-In-Hydrogel Delivery System for Polyphenols

Inhibition of interaction between Staphylococcus aureus α-hemolysin and erythrocytes membrane by hydrolysable tannins: structure-related activity study

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