RESUMEN
Periodontal diseases result from the interaction of bacterial pathogens with the host's gingival tissue. Gingival epithelial cells are constantly challenged by microbial cells and respond by altering their transcription profiles, inducing the production of inflammatory mediators. Different transcription profiles are induced by oral bacteria and little is known about how the gingival epithelium responds after interaction with the periodontopathogenic organism Aggregatibacter actinomycetemcomitans. In the present study, we examined the transcription of genes involved in signaling transduction pathways in gingival epithelial cells exposed to viable A. actinomycetemcomitans. Immortalized gingival epithelial cells (OBA-9) were infected with A. actinomycetemcomitans JP2 for 24 h and the transcription profile of genes encoding human signal transduction pathways was determined. Functional analysis of inflammatory mediators positively transcribed was performed by ELISA in culture supernatant and in gingival tissues. Fifteen of 84 genes on the array were over-expressed (P < 0.01) after 24 h of infection with viable A. actinomycetemcomitans. Over-expressed genes included those implicated in tissue remodeling and bone resorption, such as CSF2, genes encoding components of the LDL pathway, nuclear factor-κB-dependent genes and other cytokines. The ELISA data confirmed that granulocyte-macrophage colony-stimulating factor/colony-stimulating factor 2, tumor necrosis factor-α and intercellular adhesion molecule-1 were highly expressed by infected gingival cells when compared with control non-infected cells, and presented higher concentrations in tissues from patients with aggressive and chronic periodontitis than in tissues from healthy controls. The induction in epithelial cells of factors such as the pro-inflammatory cytokine CSF2, which is involved in osteoclastogenesis, may help to explain the outcomes of A. actinomycetemcomitans infection.
Asunto(s)
Aggregatibacter actinomycetemcomitans/fisiología , Periodontitis Agresiva/genética , Periodontitis Crónica/genética , Citocinas/biosíntesis , Encía/microbiología , Transducción de Señal/genética , Periodontitis Agresiva/metabolismo , Apoptosis , Adhesión Bacteriana , Estudios de Casos y Controles , Línea Celular Transformada , Periodontitis Crónica/metabolismo , Factores Estimulantes de Colonias/biosíntesis , Medios de Cultivo Condicionados , Células Epiteliales/microbiología , Perfilación de la Expresión Génica , Encía/citología , Encía/metabolismo , Factor Estimulante de Colonias de Granulocitos y Macrófagos/biosíntesis , Humanos , Molécula 1 de Adhesión Intercelular/biosíntesis , Transcripción Genética , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
Evidence is provided that conditioned medium from a macrophage-like cell line contains molecules of approximately 45 kd molecular weight with granulocyte colony-stimulating factor (G-CSF)-like activity as well as with the property of inducing granulocytes to phagocytose latex particles and to mature morphologically. This type of differentiation was found to be induced on either bone marrow or induced granulocytes, but not on resident or induced macrophages. On the other hand, resident but not induced macrophages are shown to induce these types of activities when challenged by bacterial lipopolysaccharides. Evidence that macrophages produce a factor that is mitogenic for fibroblasts is also provided. This activity was measured by the induction of increased proliferation by either low-density or saturated cultures of fibroblasts. Human recombinant G-CSF was employed and found also to possess these dual capabilities of inducing both the proliferation and differentiation of granulocytes as well as the proliferation of fibroblasts. Finally, a mechanism for the regulation of myeloid cell production and differentiation is described in which G-CSF produced by macrophages not only induces granulocytes to differentiate but induces fibroblasts to proliferate and secrete macrophage colony-stimulating factor (M-CSF), which in turn makes myeloid monocyte precursors proliferate and secrete more G-CSF.
Asunto(s)
Factores Estimulantes de Colonias/farmacología , Fibroblastos/citología , Granulocitos/fisiología , Macrófagos/metabolismo , Fagocitosis , Animales , Células de la Médula Ósea , Diferenciación Celular , División Celular , Línea Celular , Factores Estimulantes de Colonias/biosíntesis , Factores Estimulantes de Colonias/metabolismo , Femenino , Fibroblastos/metabolismo , Factor Estimulante de Colonias de Granulocitos , Granulocitos/citología , Factor Estimulante de Colonias de Macrófagos , Masculino , Ratones , Peso Molecular , Proteínas Recombinantes/farmacologíaRESUMEN
Granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF enhance phagocyte survival and function and are produced by fibroblasts and endothelial cells after induction by inflammatory mediators such as IL-1. Our ability to detect G-CSF and GM-CSF activity in the conditioned medium of the human astroglial tumor cell line, U87MG, and molecularly clone the cDNA for G-CSF from a U87MG cDNA library raised the possibility that astroglial cells are capable of G-CSF and GM-CSF production within the central nervous system; if so, the production of these CSF by astroglial cells may be inducible by IL-1. We examined the effects of IL-1 alpha and IL-1 beta on the production of G-CSF and GM-CSF by U87MG and U373MG, another astroglial tumor cell line that does not constitutively produce CSF. We demonstrate that both U87MG and U373MG can be induced to produce G-CSF and GM-CSF by exposure to IL-1 alpha and IL-1 beta. This response, measured by accumulation of increased CSF mRNA, is rapid, sensitive and due to the enhanced stability of CSF message following IL-1 exposure. The implications of these findings to the immunopathogenesis of central nervous system infections are discussed.
Asunto(s)
Astrocitoma/metabolismo , Factores Estimulantes de Colonias/biosíntesis , Sustancias de Crecimiento/biosíntesis , Interleucina-1/farmacología , Northern Blotting , Factores Estimulantes de Colonias/genética , Expresión Génica/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos , Factor Estimulante de Colonias de Granulocitos y Macrófagos , Sustancias de Crecimiento/genética , Humanos , Técnicas In Vitro , ARN Mensajero/genética , ARN Mensajero/metabolismo , Células Tumorales CultivadasRESUMEN
Although different populations of inflammatory cells infiltrate the healing wound, the mechanisms by which they influence the healing process in vivo are poorly defined. In vitro studies suggest that these cells may mediate wound healing by releasing various cytokines within the wound. We measured the levels of interleukin (IL) 1, IL-2, IL-3, IL-4, IL-6, tumor necrosis factor, and macrophage colony-stimulating factor within a subcutaneously implanted polyurethane sponge on various days after injury. Significantly higher levels of IL-1, IL-6, tumor necrosis factor, and macrophage colony-stimulating factor were detected in the wound fluid compared with basal serum levels in nonwounded mice. Tumor necrosis factor, macrophage colony-stimulating factor, and IL-6 peaked earlier than IL-1; however, the levels of these cytokines had fallen by the 13th day after wounding. Interleukin 2, IL-3, and IL-4 could not be detected in the wound fluid, and the wound fluid inhibited the proliferation of the IL-2-dependent cell lines CTLL-2 and HT-2 in response to recombinant IL-2. We hypothesize that tumor necrosis factor, macrophage colony-stimulating factor, IL-1, and IL-6, which are secreted at the site of injury, interact to promote tissue remodeling. The decrease in the levels of these cytokines by the 13th day after wounding may be the result of a regulatory process by the healed wound.