Salmonella proteomics under oxidative stress reveals coordinated regulation of antioxidant defense with iron metabolism and bacterial virulence

• Published in: Journal of proteomics Vol. 157; pp. 52 - 58
• Main Authors: Fu, Jiaqi, Qi, Linlu, Hu, Mo, Liu, Yanhua, Yu, Kaiwen, Liu, Qian, Liu, Xiaoyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 22.03.2017
• Subjects: Antioxidant defense; Antioxidants - metabolism; Bacterial Proteins - metabolism; Bacterial virulence; Hydrogen Peroxide - pharmacology; Iron - metabolism; Oxidative stress; Oxidative Stress - drug effects; Proteomics; Salmonella proteomics; Salmonella typhimurium - metabolism; Salmonella typhimurium - pathogenicity; Virulence Factors - metabolism; Oxidative stress; Iron metabolism; Bacterial virulence; Salmonella proteomics; Antioxidant defense
• ISSN: 1874-3919; 1876-7737
• DOI: 10.1016/j.jprot.2017.02.004

Salmonella Typhimurium is a bacterial pathogen that can cause widespread gastroenteritis. Salmonella encounters reactive oxygen species both under free-living conditions and within their mammalian host during infection. To study its response to oxidative stress, we performed the first large-scale proteomic profiling of Salmonella upon exposure to H2O2. Among 1600 detected proteins, 83 proteins showed significantly altered abundance. Interestingly, only a subset of known antioxidants was induced, likely due to distinct regulatory mechanisms. In addition, we found elevation of several Salmonella acquired phage products with potential contribution to DNA repair under oxidative stress. Furthermore, we observed robust induction of iron-uptake systems and disruption of these pathways led to bacterial survival defects under H2O2 challenge. Importantly, this work is the first to report that oxidative stress severely repressed the Salmonella type III secretion system (T3SS), reducing its virulence. Biological significance Salmonella, a Gram-negative bacterial pathogen, encounters reactive oxygen species (ROS) both endogenously and exogenously. To better understand its response to oxidative stress, we performed the first large-scale profiling of Salmonella protein expression upon H2O2 treatment. Among 1600 quantified proteins, the abundance of 116 proteins was altered significantly. Notably, iron acquisition systems were induced to promote bacterial survival under oxidative stress. Furthermore, we are the first to report that oxidative stress severely repressed Salmonella type III secretion system and hence reduced its virulence. We believe that these findings will not only help us better understand the molecular mechanisms that Salmonella has evolved to counteract ROS but also the global impact of oxidative stress on bacterial physiology. [Display omitted] •A global survey of Salmonella proteome under oxidative stress•Induction of most known antioxidant proteins and DNA repair machinery•Up-regulation of iron acquisition systems to promote bacterial survival•Inhibition of Salmonella type III secretion system and bacterial virulence