Identification of genetic polymorphisms associated with inter-individual variation in immune response to Mycobacterium tuberculosis infection.
Deciphering the genetic architecture of variation in the immune response to Mycobacterium tuberculosis infection.
Sex
View SamplesThe W-Beijing family of Mycobacterium tuberculosis (Mtb) strains is known for its high-prevalence and -virulence, as well as for its genetic diversity, as recently reported by our laboratories and others. However, little is known about how the immune system responds to these strains. To explore this issue, here we used reverse engineering and genome-wide expression profiling of human macrophage-like THP-1 cells infected by different Mtb strains of the W-Beijing family, as well as by the reference laboratory strain H37Rv. Detailed data mining revealed that host cell transcriptome responses to H37Rv and to different strains of the W-Beijing family are similar and overwhelmingly induced during Mtb infections, collectively typifying a robust gene expression signature ("THP1r2Mtb-induced signature"). Analysis of the putative transcription factor binding sites in promoter regions of genes in this signature identified several key regulators, namely STATs, IRF-1, IRF-7, and Oct-1, commonly involved in interferon-related immune responses. The THP1r2Mtb-induced signature appeared to be highly relevant to the interferon-inducible signature recently reported in active pulmonary tuberculosis patients, as revealed by cross-signature and cross-module comparisons. Further analysis of the publicly available transcriptome data from human patients showed that the signature appears to be relevant to active pulmonary tuberculosis patients and their clinical therapy, and be tuberculosis specific. Thus, our results provide an additional layer of information at the transcriptome level on mechanisms involved in host macrophage response to Mtb, which may also implicate the robustness of the cellular defense system that can effectively fight against genetic heterogeneity in this pathogen.
An interferon-related signature in the transcriptional core response of human macrophages to Mycobacterium tuberculosis infection.
Cell line
View SamplesAnalysis of a SigX knockout mutant of Pseudomonas aeruginosa H103 strain in minimal medium with glucose as carbon source (M9G).
The extra-cytoplasmic function sigma factor sigX modulates biofilm and virulence-related properties in Pseudomonas aeruginosa.
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View SamplesDNA methylation is an epigenetic mark thought to be robust to environmental perturbations on a short time scale. Here, we challenge that view by demonstrating that the infection of human dendritic cells with a live pathogenic bacteria is associated with rapid changes in methylation levels at thousands of loci. We performed an integrated analysis of data on genome-wide DNA methylation, histone mark patterns, chromatin accessibility, and gene expression, before and after infection. We found that infection-induced changes in methylation rarely occur at promoter regions and instead localize to distal enhancer elements. Active demethylation is associated with extensive epigenetic remodeling, including the gain of histone activation marks and the induction of enhancer RNAs, and is strongly predictive of changes in the expression levels of nearby genes. Collectively, our observations show that active, rapid changes in DNA methylation in enhancers play a previously unappreciated role in regulating the transcriptional response of immune cells to infection. Overall design: Transcriptional profiles (polyA+) of 6 non-infected and 6 MTB-infected dendritic cell samples.
Bacterial infection remodels the DNA methylation landscape of human dendritic cells.
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View SamplesAnalysis of a SigX knockout mutant of Pseudomonas aeruginosa H103 strain in LB.
The absence of SigX results in impaired carbon metabolism and membrane fluidity in Pseudomonas aeruginosa.
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