Simvastatin Reduces Chlamydophila pneumoniae –Mediated Histone Modifications and Gene Expression in Cultured Human Endothelial Cells

Abstract

Abstract-Inflammatory activation of the endothelium by Chlamydophila pneumoniae infection has been implicated in the development of chronic vascular lesions and coronary heart disease by seroepidemiological and animal studies. We tested the hypothesis that C pneumoniae induced inflammatory gene expression is regulated by Rho-GTPase-related histone modifications. C pneumoniae infection induced the liberation of proinflammatory interleukin-6, interleukin-8, granulocyte colony-stimulating factor, macrophage inflammatory protein-1␤, granulocyte/macrophage colonystimulating factor, and interferon-␥ by human endothelial cells. Cytokine secretion was reduced by simvastatin and the specific Rac1 inhibitor NSC23766 but was synergistically enhanced by inhibitors of histone deacetylases trichostatin A and suberoylanilide hydroxamic acid. Infection of endothelial cells with viable C pneumoniae, but not exposure to heat-inactivated C pneumoniae or infection with C trachomatis, induced acetylation of histone H4 and phosphorylation and acetylation of histone H3. Pretreatment of C pneumoniae-infected cells with simvastatin or NSC23766 reduced global histone modifications as well as specific modifications at the il8 gene promoter, as shown by chromatin immunoprecipitation. Reduced recruitment of nuclear factor B p65/RelA as well as of RNA polymerase II was observed in statin-treated cells. Taken together, Rac1-mediated histone modifications seem to play an important role in C pneumoniae-induced cytokine production by human endothelial cells. Key Words: endothelial cells Ⅲ cytokines Ⅲ statins Ⅲ Chlamydophila pneumoniae Ⅲ histones C hlamydia are Gram-negative bacteria that are obligate intracellular parasites of eukaryotic cells, including endothelial cells. Although chronic or recurrent infections with Chlamydophila pneumoniae have been associated with the development of vascular lesions and atherosclerosis, little is known about the molecular pathogenesis. [1][2][3][4] Infection of endothelial cells with C pneumoniae may initiate and perpetuate local inflammation by inducing cytokine release (eg, interleukin [IL]-6, IL-8) and adhesion molecule expression (P-/E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1), which subsequently results in recruitment of inflammatory cells to the endothelium. 5,6 Infection of the endothelium by Chlamydia is recognized by different pattern-recognition receptors. Membrane-bound Toll-like receptors TLR2 and TLR4 have been demonstrated to mediate host defense against C pneumoniae or chlamydial components. [7][8][9][10] In addition, the nucleotide-binding oligomerization domain protein NOD1 was identified as part of a cytosolic surveillance system detecting intracellular Chlamydia in human endothelial cells. 11 The detection of pathogens by these pattern-recognition receptors resulted in the activation of complex signaling pathways, including the stimulation of nuclear factor (NF)-B-dependent gene transcription. 12 Increasing evidence indicates that histone modificatio...

Legionella pneumophila-induced IκBζ-dependent expression of interleukin-6 in lung epithelium

“…Upon infection of cells with L. pneumophila, histone H3 gets phosphoacetylated and H4 acetylated at the ikbf gene promoter, indicative of chromatin remodeling associated with transcriptional activity [14,33,34,51]. This was accompanied by recruitment of p50 and p65 NF-kB subunits, which are known to be important for IkBf expression [52].…”

“…Chromatin immunoprecipitation (ChIP) A549 cells were infected with L. pneumophila as indicated and then subjected to ChIP assay as previously described [14,28,33,34] using anti-mRNA polymerase II (Pol II) (N-20), anti-p65 (C-20), anti-p50, anti-C/EBPb (Santa Cruz Biotechnologies, Santa Cruz, CA, USA), anti-P-cJun (Cell Signalling Technology, Danvers, MA, USA), anti-P Ser10 /Ac Lys14 -H3, Pan-Ac-H4 (Upstate, Lake Placid, NY, USA) and anti-IkBf (Acris Antibodies GmbH, Hiddenhausen, Germany). The il6 and ikbf enhancer region was amplified by PCR using HotStarTaq polymerase (Qiagen, Hilden, Germany) and specific primers as followed: il6 sense 59-ACAAATTAACTGGAACGCT-39, antisense 59-ATTGGGGG TTGAGACTCTAA-39 and ikbf sense 59-AGGGGAATGTCC GGGACT-39, antisense 59-TAATGTCTGACCTCGTGGCAA-39.…”

Identification and Predictive Value of Interleukin-6 + Interleukin-10 + and Interleukin-6 − Interleukin-10 + Cytokine Patterns in ST-Elevation Acute Myocardial Infarction

“…[30][31][32][33] The response of endothelial cells infected by Chlamydophila pneumoniae is similar to most features of IL-6 + IL-10 + STEMI patients. 34 Alternatively, the high IL-6 levels reported in a fraction of STEMI patients could indicate a diverse response to myocardial injury. [35][36][37] Downregulation of glycoprotein 130-mediated (IL-6 receptor subunit) signal transducer and activator of transcription 3 in an experimental model of myocardial infarction plays an important role in limiting cardiac inflammation and adverse remodeling.…”

Essential Role of Mitochondrial Antiviral Signaling, IFN Regulatory Factor (IRF)3, and IRF7 in Chlamydophila pneumoniae-Mediated IFN-β Response and Control of Bacterial Replication in Human Endothelial Cells

“…C. pneumoniae has been suggested to accelerate endothelial inflammation and therefore promoting vascular diseases (68), and indeed, C. pneumoniae infection of endothelial cells has been demonstrated to induce the release of chemoattractants, proinflammatory cytokines, and myeloid growth factors (44,69), cytokines that are also thought to be involved in atherosclerosis (70)(71)(72)(73). Activation of IRF3 has recently been linked to the development of atherosclerosis by mediating defects in cholesterol clearance (74).…”

“…HUVECs were infected with C. pneumoniae as indicated and subjected to a chromatin immunoprecipitation (ChIP) assay using anti-IRF3, anti-IRF7, and anti-p65-Abs or a control normal rabbit IgG (Santa Cruz Biotechnology) as described previously (39,44). The IFN-b enhancer region was amplified by PCR using specific primers as follows: sense, 59-GAATCCACGGATACAGAACCT-39, and antisense, 59-TTGACAACA-CGAACAGTGTCG-39 (TIB Molbiol).…”