Proteomic Investigation of the Time Course Responses of RAW 264.7 Macrophages to Infection with Salmonella enterica

Abstract

To investigate the extent to which macrophages respond to Salmonella infection, we infected RAW 264.7 macrophages with Salmonella enterica serotype Typhimurium and analyzed macrophage proteins at various time points following infection by using a global proteomic approach. A total of 1,006 macrophage and 115 Salmonella proteins were identified with high confidence. Most of the Salmonella proteins were observed in the late stage of the infection time course, which is consistent with the fact that the bacterial cells proliferate inside RAW 264.7 macrophages. The peptide abundances of most of the identified macrophage proteins remained relatively constant over the time course of infection. Compared to those of the control, the peptide abundances of 244 macrophage proteins (i.e., 24% of the total identified macrophage proteins) changed significantly after infection. The functions of these Salmonella-affected macrophage proteins were diverse, including production of antibacterial nitric oxide (i.e., inducible nitric oxide synthase), production of prostaglandin H 2 (i.e., cyclooxygenase 2), and regulation of intracellular traffic (e.g., sorting nexin 5 [SNX5], SNX6, and SNX9). Diverse functions of the Salmonella-affected macrophage proteins demonstrate a global macrophage response to Salmonella infection. Western blot analysis not only confirmed the proteomic results for a selected set of proteins but also revealed that (i) the protein abundance of mitochondrial superoxide dismutase increased following macrophage infection, indicating an infection-induced oxidative stress in mitochondria, and (ii) in contrast to infection of macrophages by wild-type Salmonella, infection by the sopB deletion mutant had no negative impact on the abundance of SNX6, suggesting a role for SopB in regulating the abundance of SNX6.

Impact of Salmonella Infection on Host Hormone Metabolism Revealed by Metabolomics

“…Chlamydia trachomatis infection also induces COX-2 expression and PGE 2 production in cultured epithelial cells (8). The infection of cultured macrophages with Salmonella has also been shown to induce the expression of COX-2 mRNA and protein, as well as the production of PGE 2 and PGI 2 (29,36). Although some information regarding the impact of Salmonella infection on eicosanoid metabolism is available, our results show that this effect is much more profound than previously appreciated.…”

“…Although much is known regarding the effects of Salmonella on the host, most studies have focused on the analysis of individual host metabolic pathways. A few global studies on the effect of Salmonella infection on the host have been performed, using both transcriptomic and proteomic techniques (29,40). However, the effect of Salmonella on the biochemical composition of host tissues remains unknown.…”

Proteomics for development of vaccine

“…They collected data from 32 published papers describing 77 different host-pathogen interactions [79]. There is a large body of data presenting the cellular response to infection on the proteome level, which is an important indicator of what type of immune response should be induced by immunization to get the desired protective effect [80,81]. To avoid misinterpretation of results, researchers have to be aware that most of the cell lines used are of a tumor origin and subsequently their protein profiles are similar but not identical to protein profiles of the cells present in the host tissues [82].…”

Foodomics and Food Safety: Where We Are

“…Otherwise, this profi le could be obtained by applying a combination of multiple analytical techniques (196). Proteomic investigation of the interaction of foodborne pathogen Salmonella enterica with macrophages gave important information about the pathogenicity of this bacterium (197). Orbitrap mass spectro meters are also frequently used for the determination of food contaminants and metabolites (55,56).…”