RESUMO
Chlamydia pneumoniae causes respiratory infections. In chronic diseases associated with Chlamydia, such as arteriosclerosis, C. pneumoniae is present in a persistent form, which might participate in pathogenesis of chronic inflammatory disease. To elucidate how these intracellular bacteria modulate host-cells during persistence, we compared the expression pattern of a range of host genes after short (24 h) and long (up to 7 days) times of chlamydia infection in HeLa-cells. One day post infection, in three cell-culture models of persistence, namely treatment with penicillin or IFN-gamma, or iron-depletion, infection induced the genes of CTGF, IL-6, IL-8, IL-11, LIF, EGR-1 and ETV4 in a similar fashion. However, after a longer time, two modes of host-cell reaction emerged that were dependent on the persistence model used. After IFN-gamma and penicillin treatment chlamydia-induced host-cell gene expression was inhibited, while it stayed upregulated in iron-depletion. Human monocytes/macrophages, in which persistence naturally occurs, were additionally investigated: for several genes, UV-inactivated and viable chlamydia caused long-lasting upregulation. Thus, this study reveals (i) the ability of C. pneumoniae to participate in two putative pathomechanisms of persistence, silencing and permanent activation, which might represent different in vivo situations and (ii) a strong dependence on the mode of persistence induction.
Assuntos
Infecções por Chlamydia/metabolismo , Chlamydophila pneumoniae/fisiologia , Perfilação da Expressão Gênica , Inativação Gênica , Proteínas Imediatamente Precoces/biossíntese , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Regulação para Cima , Proteínas E1A de Adenovirus/biossíntese , Proteínas E1A de Adenovirus/genética , Infecções por Chlamydia/microbiologia , Chlamydophila pneumoniae/genética , Fator de Crescimento do Tecido Conjuntivo , Meios de Cultura , Proteína 1 de Resposta de Crescimento Precoce/biossíntese , Proteína 1 de Resposta de Crescimento Precoce/genética , Ensaio de Imunoadsorção Enzimática , Células HeLa , Humanos , Técnicas In Vitro , Interferon gama/farmacologia , Interleucinas/biossíntese , Interleucinas/metabolismo , Deficiências de Ferro , Modelos Biológicos , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Monócitos/microbiologia , Penicilina G/farmacologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-ets , Proteínas RecombinantesRESUMO
Period (Per) genes are involved in regulation of the circadian clock and are thought to modulate several brain functions. We demonstrate that Per2(Brdm1) mutant mice, which have a deletion in the PAS domain of the Per2 protein, show alterations in the glutamatergic system. Lowered expression of the glutamate transporter Eaat1 is observed in these animals, leading to reduced uptake of glutamate by astrocytes. As a consequence, glutamate levels increase in the extracellular space of Per2(Brdm1) mutant mouse brains. This is accompanied by increased alcohol intake in these animals. In humans, variations of the PER2 gene are associated with regulation of alcohol consumption. Acamprosate, a drug used to prevent craving and relapse in alcoholic patients is thought to act by dampening a hyper-glutamatergic state. This drug reduced augmented glutamate levels and normalized increased alcohol consumption in Per2(Brdm1) mutant mice. Collectively, these data establish glutamate as a link between dysfunction of the circadian clock gene Per2 and enhanced alcohol intake.
Assuntos
Consumo de Bebidas Alcoólicas/genética , Ácido Glutâmico/genética , Proteínas Nucleares/genética , Taurina/análogos & derivados , Acamprosato , Dissuasores de Álcool/farmacologia , Consumo de Bebidas Alcoólicas/metabolismo , Alcoolismo/genética , Alcoolismo/metabolismo , Sistema X-AG de Transporte de Aminoácidos/metabolismo , Animais , Relógios Biológicos/genética , Relógios Biológicos/fisiologia , Proteínas de Ciclo Celular , Cocaína/metabolismo , Transtornos Relacionados ao Uso de Cocaína/genética , Transtornos Relacionados ao Uso de Cocaína/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Camundongos , Proteínas Nucleares/metabolismo , Proteínas Circadianas Period , Taurina/farmacologia , Fatores de Tempo , Fatores de TranscriçãoRESUMO
The transcription factor activator protein (AP)-1 plays crucial roles in proliferation, cell death, and the immune response. c-JUN is an important component of AP-1, but only very few c-JUN response genes have been identified to date. Activity of c-JUN is controlled by NH2-terminal phosphorylation (JNP) of its transactivation domain by a family of JUN-NH2-terminal protein kinases (JNK). JNK form a stable complex with c-JUN in vitro and in vivo. We have targeted this interaction by means of a cell-permeable peptide containing the JNK-binding (delta) domain of human c-JUN. This peptide strongly and specifically induced apoptosis in HeLa tumor cells, which was paralleled by inhibition of serum-induced c-JUN phosphorylation and up-regulation of the cell cycle inhibitor p21cip/waf. Application of the c-JUN peptide to interleukin (IL)-1-stimulated human primary fibroblasts resulted in up-regulation of four genes, namely COX-2, MnSOD, I kappa B alpha, and MAIL and down-regulation of 10 genes, namely CCL8, mPGES, SAA1, hIAP-1, hIAP-2, pent(r)axin-3, CXCL10, IL-1 beta, ICAM-1, and CCL2. Only a small group of genes, namely pent(r)axin-3, CXCL10, ICAM-1, and IL-1 beta, was inhibited by both the c-JUN peptide and the JNK inhibitor SP600125. Thereby, and by additional experiments using small interfering RNA to suppress endogenous c-JUN we identify for the first time three distinct groups of inflammatory genes whose IL-1-induced expression depends on c-JUN, on JNK, or on both. These results shed further light on the complexity of c-JUN-JNK-mediated gene regulation and also highlight the potential use of dissecting signaling downstream from JNK to specifically target proliferative diseases or the inflammatory response.