Project description:Listeria monocytogenes causes severe foodborne illness in pregnant women and immunocompromised individuals. After the intestinal phase of infection, the liver plays a central role in the clearance of this pathogen through its important functions in immunity. However, recent evidence suggests that subpopulations of L. monocytogenes may escape eradication after prolonged infection of hepatocytes, by entering a persistence phase in vacuoles. Here, we examine whether this long-term infection alters hepatocyte defense pathways, which may be instrumental for bacterial persistence. We first established models of Listeria infection in human hepatocyte cell lines HepG2 and Huh7 and in primary mouse hepatocytes (PMH). In these cells, Listeria efficiently enters the persistence stage after a 3-day infection, while inducing a type I (PMH) or type I/III (HepG2) or no (Huh7) interferon response. RNA-seq analysis identified a common signature of long-term Listeria infection on the hepatocyte transcriptome, characterized by overexpression of a set of genes involved in antiviral immunity and under-expression of many acute phase protein (APP) genes, particularly involved in the complement and coagulation systems. The decrease in APP transcript amounts correlated with lower protein abundance in the secretome of infected cells, as shown by proteomics, and also occurred in the presence of APP inducers (IL-6 or IL-1b). The results also suggest that long-term Listeria infection affects lipid metabolism pathways. Collectively, these results reveal that long-term infection with L. monocytogenes profoundly deregulates the innate immune functions of hepatocytes, which could generate an environment favorable to the establishment of persistent infection.
Project description:Persistence of Listeria monocytogenes in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads, and cheeses. We previously discovered strong evidence of L. monocytogenes persistence in delis across multiple states. We hypothesized that this was correlated with isolates’ innate characteristics, such as biofilm-forming capacity or gene differences.We further chose four isolates for RNA-sequencing analysis and compared their global biofilm transcriptome to their global planktonic transcriptome. Analysis of biofilm vs planktonic gene expression did not show the expected differences in gene expression patterns. Overall, L. monocytogenes persistence in the deli environment is likely a matter of poor sanitation and/or facility design, rather than isolates’ biofilm-forming capacity, sanitizer tolerance, or genomic content
Project description:Listeria monocytogenes is a human, food-borne pathogen. Genomic comparisons between L. monocytogenes and Listeria innocua, a closely related non-pathogenic species, were pivotal in the identification of protein coding genes essential for virulence. However, no comprehensive comparison has focused on the non-coding genome. We used strand-specific cDNA sequencing to produce genome-wide transcription start site (TSS) maps for both organisms, and developed a publicly available integrative browser to visualize and analyze both transcriptomes in different growth conditions and genetic backgrounds. Our data revealed conservation across most transcripts, but significant divergence between the species in a subset of non-coding RNAs. In L. monocytogenes we identified 113 sRNAs and 70 asRNAs, significantly increasing the repertoire of non coding RNAs in this species. Remarkably, we identified a class of long antisense transcripts (lasRNAs) that overlap one gene while also serving as the 5M-bM-^@M-^Y UTR of the adjacent divergent gene. Experimental evidence suggests that lasRNAs transcription inhibits expression of one operon while activating the expression of another. Such lasRNA/operon structure, termed "excludon", might represent a novel form of regulation in bacteria. Construction of consensus TSS-maps in Listeria monocytogenes and Listeria innocua by applying 5'-end sequencing on samples in different conditions and genetic backgrounds.
Project description:Ileal profiles from gnotobiotic mice mono-associated with Listeria species or B. thetaiotaomicron. Samples were derived from 72h colonizations of Fabpi-hEcad transgenic B6 mice fed a standard-chow polysaccharide rich (PR) diet. Keywords: Germ-free vs. Mono-associations
2007-04-23 | GSE7013 | GEO
Project description:Comparatic genomics of Listeria species
Project description:We infected wild type L. monocytogenes EGD-e (1) and its isogenic deltahlydeltaplcA (2) (lacking the ability to breach the vacuolar compartment of host cells following uptake) mutant strain to human intestinal epithelial cell line (Caco-2) with an MOI of 100 and 500 respectively. Bacterial total RNA was isolated at 1 h (deltahlydeltaplcA) and 4 h (EGD-e) post infection, reverse transcribed, hybridised to whole genome microarray and microarray data was analysed as described previously (3) 1. Glaser et al. 2001. Comparative genomics of Listeria species. Science 294:849-852. 2. Paschen et al. 2000. Human dendritic cells infected by Listeria monocytogenes: induction of maturation, requirements for phagolysosomal escape and antigen presentation capacity. Eur.J.Immunol. 30:3447-3456. 3. Chatterjee et al. 2006. Intracellular gene expression profile of Listeria monocytogenes. Infect.Immun. 74:1323-1338.
Project description:Failure of adoptive T cell therapies in cancer patients is linked to limited T cell expansion and persistence, even in memory-prone 41BB-(BBz)-based chimeric antigen receptor (CAR) T cells. In murine CD8+ T cells, SUV39H1 promotes differentiation and expansion of effector CD8+ T cells during acute infection by Listeria monocytogenes by silencing stemness and memory genes (Pace et al. Science, 2018). The purpuse of this study is to investigate the transcriptomic differences of SUV39H1 knock-out versus mock human 41BBz-CAR T cells by Nanostring at different cycles of restimulation.