A Dual-Action Molecule Suppresses S. aureus Infection as an Inhibitor Targeting Hla Pore Formation and TLR2 Signaling

Inhibiting Staphylococcus aureus Virulence Factors: Advances in Traditional Chinese Medicines and Active Compounds

Staphylococcus aureus is one of the most prevalent antibiotic-resistant bacteria, characterized by high morbidity and mortality. The pathogenicity of S. aureus relies on the production of multiple virulence factors. In recent years, antivirulence strategies have shown promise in developing antiinfective drugs by targeting the inhibition of bacterial virulence factors rather than directly killing pathogens. In Asia, some traditional Chinese medicines have a long history of antiinfective application and have demonstrated therapeutic efficacy. However, their antiinfective mechanism has not been fully elucidated. Recent studies have revealed that numerous extracts of TCM, as well as pure compounds from TCM, significantly inhibited the expression of virulence factors of S. aureus, which might be one of their antiinfective mechanisms with potential for the development of novel antiinfective agents. In this review, we summarized the major virulence factors of S. aureus and recent advances in TCM-derived antivirulence agents, including TCM formulae, single herbs, and isolated bioactive compounds, which showed antivirulence capability against S. aureus. Investigating the antivirulence mechanism of TCM not only enhances our understanding of TCM's antiinfective mechanisms but also facilitates the isolation of active compounds with therapeutic potential against S. aureus infection.

The first identification of three AdIRAK2 genes from an evolutionarily important amphibian Andrias davidianus and their involvement in NF-κB activation and inflammatory responses

Interleukin-1 receptor associated kinases (IRAK) is the most important downstream kinases of TLRs/IL-1R signaling pathway for signal transduction and activation of inflammatory response against pathogen infections. However, the molecular identification and function characterization of IRAK2 homologs in lower vertebrate remains obscure. In this study, three IRAK2 genes (AdIRAK2a, AdIRAKb and AdIRAK2c) and their respective transcripts were identified from the Chinese giant salamander Andrias davidianus. This is the first evidence that three different IRAK2 genes exist in an ancient amphibian species, which has never been reported in other vertebrates. The complete open reading frames (ORFs) of AdIRAK2a, AdIRAK2b and AdIRAK2c were 2112 bp, 1917 bp and 816 bp encoding deduced proteins of 703 amino acids (aa), 628 aa and 271 aa, respectively. All three AdIRAK2 proteins contained two predicted conserved functional domains, including a death domain (DD) and a serine/threonine protein kinases domain (KD). Phylogenetic analysis showed that the three AdIRAK2s clustered together with other known IRAK2 of vertebrates. The three AdIRAK2s were ubiquitously expressed in all tested tissues with a similar tissues distribution pattern. After challenge of Aeromonas hydrophila (A. hydrophila), Staphylococcus aureus (S.aureus), giant salamander iridovirus (GSIV, belonging to the genus Ranavirus in the family Iridoviridae) and polyinosinic:polycytidylic acid (poly(I:C)), the expression levels of all AdIRAK2s in blood were significantly altered, however, they exhibited distinct response patterns. Moreover, the results of over-expression and RNAi of AdIRAK2s implied the involvement of AdIRAK2s in triggering NF-κB-mediated signaling pathways and inflammatory responses. This study might provide a better understanding of the presence and immune regulation function of IRAK2 in amphibians and even in vertebrates.