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Microarray analysis for M1SF370 Streptococcus pyogenes internalized in Detroit 562 human pharyngeal cells.

ABSTRACT: A total of 432 genes were found to be differentially expressed in M1SF370 bacterial population internalized in Detroit 562 human pharyngeal cells when compared with the same strain incubated in the absence of Detroit 562 cells. While most of them (349/432 i.e. 80.8%) were up regulated, 83 genes were down regulated contributing to 19.2% of the total differentiated genes. The major contributor of the latter category was phage-related genes (35 genes). Almost ¼ of these genes (106) belonged to a category of Unknown or possible predicted function. Most notably, up-regulated genes belonged to amino acid transport , cell division, cell envelope biogenesis, DNA replication correlated well with up-regulated 67 genes belonged to translation and ribosomal structure. Further, up-regulation of 12/15 virulence-related genes indicated that human host cell internalized bacteria are highly virulent as compared to laboratory grown culture in test-tubes.

ORGANISM(S): Streptococcus pyogenes

PROVIDER: GSE27846 | GEO | 2011/06/10

SECONDARY ACCESSION(S): PRJNA138045

REPOSITORIES: GEO

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Project description:A total of 432 genes were found to be differentially expressed in M1SF370 bacterial population internalized in Detroit 562 human pharyngeal cells when compared with the same strain incubated in the absence of Detroit 562 cells. While most of them (349/432 i.e. 80.8%) were up regulated, 83 genes were down regulated contributing to 19.2% of the total differentiated genes. The major contributor of the latter category was phage-related genes (35 genes). Almost ¼ of these genes (106) belonged to a category of Unknown or possible predicted function. Most notably, up-regulated genes belonged to amino acid transport , cell division, cell envelope biogenesis, DNA replication correlated well with up-regulated 67 genes belonged to translation and ribosomal structure. Further, up-regulation of 12/15 virulence-related genes indicated that human host cell internalized bacteria are highly virulent as compared to laboratory grown culture in test-tubes. S. pyogenes strain type M1 SF370 (wild-type) was procured from ATCC (ATCC 700294). Detroit 562 pharyngeal cells were obtained from ATCC and maintained in MEM with 10% FBS in humidified CO2-incubator. Purified cDNA preparations from the Detroit cells-internalized bacteria and that were cultured without Detroit cells, were labeled with either Alexafluor-555 or Alexafluor-647 depending on the experimental design ( i.e. dye swap experiment). Differentially labeled probes were then combined and purified. Using four independently isolated RNA preparations (biological replicates), a total of 8 experiments (incorporating 4 dye swaps) were performed. Accordingly eight hybridization measurements for this mutant were obtained. Exp-1 and -2 (GSM687276, GSM687310-dye swap) are the technical replicates of the biological sample-1, Exp-3 and -4 (GSM687311, GSM687312-dye swap) are technical replicates of biological sample-2, Exp-5 and -6, (GSM687313,GSM687319-dye swap,) are technical replicates of the biological sample-3, and finally Exp-7 and -8, (GSM687320,GSM687321-dye swap) are technical replicates of the biological sample-4. .

Project description:Infection of the human host by Streptococcus pneumoniae begins with colonization of the nasopharynx, which is mediated by adherence of bacteria to respiratory epithelium. Several studies have indicated an important role for the pneumococcal capsule in this process. Here, we used microarrays to characterize the in vitro transcriptional response of human nasopharyngeal epithelial Detroit 562 cells to adherence of serotype 2-encapsulated strain D39, serotype 19F-encapsulated strain G54, serotype 4-encapsulated strain TIGR4, and their nonencapsulated derivatives (delta-cps). In total, 322 genes were found to be upregulated in response to adherent pneumococci. Twenty-two genes were commonly induced, including those encoding several cytokines (e.g., IL-1-beta, IL-6), chemokines (e.g., IL-8, CXCL1/2), and transcriptional regulators (e.g., FOS), consistent with an innate immune response mediated by Toll-like receptor signaling. Interestingly, 85% of genes was induced specifically by one or more encapsulated strains, suggestive of a capsule-dependent response. Importantly, purified capsular polysaccharides alone had no effect. Over a third of these loci encoded products predicted to be involved in transcriptional regulation and signal transduction, in particular MAPK signaling pathways. Real-time PCR of a subset of ten genes confirmed microarray data and showed a time-dependent upregulation of especially innate immunity genes. Downregulation of epithelial genes was most pronounced upon adherent D39delta-cps, as 68% of the 161 genes identified was only repressed using this nonencapsulated strain. In conclusion, we identified a subset of host genes specifically induced by encapsulated strains during in vitro adherence, and have demonstrated the complexity of interactions occurring during the initial stages of pneumococcal infection. Experiment Overall Design: We used three different pneumococcal strains and their isogenic nonencapsulated derivatives (delta-cps): serotype 2-encapsulated strain D39, serotype 19F-encapsulated strain G54, and serotype 4-encapsulated strain TIGR4. All experiments were performed in triplicate (3 independent biological replicates) and compared to uninfected control Detroit 562 cells. Bacteria were allowed to adhere to the epithelial cells for 2 hours, after which the transcriptional response of the Detroit cells was analyzed using Affymetrix Human U133 Plus GeneChips. In addition to the 6 strains mentioned above, we included transcriptional analysis of the epithelial cell response to low-dose D39delta-cps (giving adherence equivalent to wild-type D39) and purified type 2 capsular polysaccharides.

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Microarray analysis for M1SF370 Streptococcus pyogenes internalized in Detroit 562 human pharyngeal cells.

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