Project description:Salmonella enterica serotype Typhimurium causes an acute inflammatory reaction in the cecum of streptomycin pre-treated mice. We determined global changes in gene expression elicited by serotype Typhimurium in the cecal mucosa. The gene expression profile was dominated by T cell derived cytokines and genes whose expression is known to be induced by these cytokines. Markedly increased mRNA levels of interferon (IFN) ï§, interleukin (IL) 22 and IL-17 were detected by quantitative real-time PCR. Furthermore, mRNA levels of genes whose expression is induced by IFNï§, IL-22 or IL-17, including macrophage inflammatory protein (MIP)-2, inducible nitric oxide synthase (iNOS), lipocalin-2, MIP-1ï¡, MIP-1ï¢, and keratinocyte-derived cytokine (KC), were also markedly increased. To assess the importance of T cells in orchestrating this pro-inflammatory gene expression profile, we depleted T cells using a monoclonal antibody prior to investigating cecal inflammation caused by serotype Typhimurium in streptomycin pre-treated mice. Depletion of CD3+ T cells resulted in a dramatic reduction in gross pathology, a significantly reduced recruitment of neutrophils and a marked reduction in mRNA levels of IFNï§, IL-22, IL-17, iNOS, lipocalin-2 and KC. Our results suggest that T cells play an important role in amplifying inflammatory responses induced by serotype Typhimurium in the cecal mucosa. Experiment Overall Design: Determine global changes in gene expression elicited by serotype Typhimurium in the cecal mucosa. For each condition, control and infected, total cecal RNA from 4 mice was pooled
Project description:To investigate the extent to which macrophages respond to Salmonella infection, researchers 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.
Project description:To determine the impact of a low Mg(2+)/pH defined growth medium (MgM) on the proteome of Salmonella enterica serotype Typhimurium, researchers cultured S. Typhimurium cells in the medium under two different conditions termed MgM Shock and MgM Dilution and then comparatively analyzed the bacterial cells harvested from these conditions by a global proteomic approach.
Project description:Streptococcus pneumoniae is a frequent coloniser of the human nasopharynx and a major cause of life-threating invasive infections such as pneumonia, meningitis and sepsis. Over 1 million people die every year due to invasive pneumococcal disease (IPD), mainly in developing countries. Serotype 1 is a common cause of IPD; however, unlike other serotypes, it is rarely found in the carrier state in the nasopharynx, which is often considered a prerequisite for disease. The aim of this study was to understand this dichotomy. We used murine models of carriage and IPD to characterise the pathogenesis of African serotype 1 (Sequence Type 217) pneumococcal strains obtained from the Queen Elizabeth Central Hospital in Blantyre, Malawi. We found that ST217 pneumococcal strains were highly virulent in a mouse model of invasive pneumonia, but in contrast to the generally accepted assumption, can also successfully establish nasopharyngeal carriage. Interestingly, we found that co-colonising serotypes may proliferate in the presence of serotype 1, suggesting that acquisition of serotype 1 carriage could increase the risk of developing IPD by other serotypes. RNAseq analysis confirmed that key virulence genes associated with inflammation and tissue invasiveness were upregulated in serotype 1. These data reveal important new insights into serotype 1 pathogenesis, with implications for carriage potential and risk of invasive disease through interactions with other co-colonising serotypes; an often overlooked factor in transmission and disease progression.
Project description:Salmonella enterica serotype Typhimurium causes an acute inflammatory reaction in the cecum of streptomycin pre-treated mice. We determined global changes in gene expression elicited by serotype Typhimurium in the cecal mucosa. The gene expression profile was dominated by T cell derived cytokines and genes whose expression is known to be induced by these cytokines. Markedly increased mRNA levels of interferon (IFN-gamma), interleukin-22 (IL-22) and IL-17 were detected by quantitative real-time PCR. Furthermore, mRNA levels of genes whose expression is induced by IFN-gamma, IL-22 or IL-17, including macrophage inflammatory protein 2 (MIP-2), inducible nitric oxide synthase (Nos2), lipocalin-2, MIP-1alpha, MIP-1beta, and keratinocyte-derived cytokine (KC), were also markedly increased. To assess the importance of T cells in orchestrating this pro-inflammatory gene expression profile, we depleted T cells using a monoclonal antibody prior to investigating cecal inflammation caused by serotype Typhimurium in streptomycin pre-treated mice. Depletion of CD3+ T cells resulted in a dramatic reduction in gross pathology, a significantly reduced recruitment of neutrophils and a marked reduction in mRNA levels of IFN-gamma, IL-22, IL-17, iNOS, lipocalin-2 and KC. Our results suggest that T cells play an important role in amplifying inflammatory responses induced by serotype Typhimurium in the cecal mucosa. Keywords: Disease state analysis