title: Isoalantolactone protects against Staphylococcus aureus pneumonia.
abstract: Staphylococcus aureus is a versatile pathogen that can cause life-threatening infections. The growing emergence of methicillin-resistant S. aureus strains and a decrease in the discovery of new antibiotics warrant the search for new therapeutic targets to combat infections. Staphylococcus aureus produces many extracellular virulence factors that contribute to its pathogenicity. Therefore, targeting bacterial virulence as an alternative strategy to the development of new antimicrobials has gained great interest. α-Toxin is a 33.2-kDa, water-soluble, pore-forming toxin that is secreted by most S. aureus strains. α-Toxin is essential for the pathogenesis of pneumonia, as strains lacking α-toxin display a profound defect in virulence. In this report, we demonstrate that isoalantolactone (IAL), a naturally occurring compound found in Inula helenium (Compositae), has no anti-S. aureus activity as per MIC evaluation in vitro. However, IAL can markedly inhibit the expression of α-toxin in S. aureus at very low concentrations. Furthermore, the in vivo data indicate that treatment with IAL protects mice from S. aureus pneumonia.
authors.affiliation: Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China.
authors.forename: Jiazhang
authors.initials: J
authors.lastname: Qiu
authors.forename: Mingjing
authors.initials: M
authors.lastname: Luo
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Dong
authors.forename: Hongen
authors.initials: H
authors.lastname: Li
authors.forename: Bingfeng
authors.initials: B
authors.lastname: Leng
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Dai
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Niu
authors.forename: Xuming
authors.initials: X
authors.lastname: Deng
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006801:Humans; D038143:Inula / Q000737:chemistry*; D051379:Mice; D008810:Mice, Inbred C57BL; D010936:Plant Extracts / Q000494:pharmacology*; D011023:Pneumonia, Staphylococcal / Q000188:drug therapy / Q000382:microbiology* / Q000517:prevention & control*; D012717:Sesquiterpenes / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D010936:Plant Extracts; D012717:Sesquiterpenes; C032787:isoalantolactone