Epigenetics and bacterial infections.

Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France.
Cold Spring Harbor Perspectives in Medicine (Impact Factor: 7.56). 12/2012; 2(12). DOI: 10.1101/cshperspect.a010272
Source: PubMed

ABSTRACT Epigenetic mechanisms regulate expression of the genome to generate various cell types during development or orchestrate cellular responses to external stimuli. Recent studies highlight that bacteria can affect the chromatin structure and transcriptional program of host cells by influencing diverse epigenetic factors (i.e., histone modifications, DNA methylation, chromatin-associated complexes, noncoding RNAs, and RNA splicing factors). In this article, we first review the molecular bases of the epigenetic language and then describe the current state of research regarding how bacteria can alter epigenetic marks and machineries. Bacterial-induced epigenetic deregulations may affect host cell function either to promote host defense or to allow pathogen persistence. Thus, pathogenic bacteria can be considered as potential epimutagens able to reshape the epigenome. Their effects might generate specific, long-lasting imprints on host cells, leading to a memory of infection that influences immunity and might be at the origin of unexplained diseases.

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    ABSTRACT: The precise cause of the antineutrophil cytoplasmic antibodies (ANCA) autoimmunity is not known and is likely to be multifactorial. Infections may trigger formation of ANCA and a fraction of the patients with infection-triggered ANCA develop ANCA-associated vasculitis.Here we discuss some of the proposed mechanisms of ANCA formation during the course of infection. They include initiation of autoimmune response by microbial peptides that are complementary to autoantigens; epigenetic silencing and antigen complementarity leading to upregulation of autoantigen genes; molecular mimicry between bacterial and self-antigens; formation of neutrophil extracellular traps that stimulate immune processes including production of ANCA; interaction of bacterial components with Toll-like receptors, which leads to formation of mediators affecting the immune responses to infections and can trigger ANCA production. Further work is needed to clarify these mechanisms and develop preventive measures and therapeutic interventions.
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    ABSTRACT: Morphological and functional changes of cells are important for adapting to environmental changes and associated with continuous regulation of gene expressions. Genes are regulated-in part-by epigenetic mechanisms resulting in alternating patterns of gene expressions throughout life. Epigenetic changes responding to the environmental and intercellular signals can turn on/off specific genes, but do not modify the DNA sequence. Most epigenetic mechanisms are evolutionary conserved in eukaryotic organisms, and several homologs of epigenetic factors are present in plants and animals. Moreover, in vitro studies suggest that the plant cytoplasm is able to induce a nuclear reassembly of the animal cell, whereas others suggest that the ooplasm is able to induce condensation of plant chromatin. Here, we provide an overview of the main epigenetic mechanisms regulating gene expression and discuss fundamental epigenetic mechanisms and factors functioning in both plants and animals. Finally, we hypothesize that animal genome can be reprogrammed by epigenetic factors from the plant protoplast.
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Jun 3, 2014