RESUMEN
Periodontitis is a common chronic inflammatory condition that results in increased levels of inflammatory cytokines and inflammatory mediators. In addition to oral disease and tooth loss, it also causes low-grade systemic inflammation that contributes to development of systemic conditions including cardiovascular disease, pre-term birth, diabetes and cancer. Chronic inflammation is associated with epigenetic change, and it has been suggested that such changes can alter cell phenotypes in ways that contribute to both ongoing inflammation and development of associated pathologies. Here we show that exposure of human gingival fibroblasts to IL-1ß increases expression of maintenance methyltransferase DNMT1 but decreases expression of de novo methyltransferase DNMT3a and the demethylating enzyme TET1, while exposure to PGE2 decreases expression of all three enzymes. IL-1ß and PGE2 both affect global levels of DNA methylation and hydroxymethylation, as well as methylation of some specific CpG in inflammation-associated genes. The effects of IL-1ß are independent of its ability to induce production of PGE2, and the effects of PGE2 on DNMT3a expression are mediated by the EP4 receptor. The finding that exposure of fibroblasts to IL-1ß and PGE2 can result in altered expression of DNA methylating/demethylating enzymes and in changing patterns of DNA methylation suggests a mechanism through which inflammatory mediators might contribute to the increased risk of carcinogenesis associated with inflammation.
Asunto(s)
ADN (Citosina-5-)-Metiltransferasa 1/metabolismo , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Dinoprostona/metabolismo , Fibroblastos/metabolismo , Interleucina-1beta/metabolismo , Oxigenasas de Función Mixta/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Células Cultivadas , ADN (Citosina-5-)-Metiltransferasa 1/genética , ADN (Citosina-5-)-Metiltransferasas/genética , Metilación de ADN , ADN Metiltransferasa 3A , Encía/citología , Humanos , Oxigenasas de Función Mixta/genética , Proteínas Proto-Oncogénicas/genéticaRESUMEN
Matrix metalloproteinases (MMPs) have both protective and pathological roles in inflammation, and transcriptional mechanisms are important in regulating physiological levels to maintain health. Zinc-binding protein-89 (ZBP-89) is a transcription factor with roles in regulating vital cellular processes, acting through complex interactions with other proteins to ensure appropriate expression of tightly regulated genes. ZBP-89 binds the MMP-3 promoter at a polymorphic (5A/6A) site along with NF-κB. This polymorphism affects MMP-3 protein levels in tissues. In disease association studies, both over- and under-expression has negative consequences to health, and this promoter element is important in maintaining balanced expression. There is evidence that effects of the polymorphism vary under different conditions, but the role of ZBP-89 in these differences is not known. ZBP-89 was stably knocked-down in MG-63 osteosarcoma cells in order to study its role in regulation of MMP-3 expression in response to cytokines, and evaluate the functionality of a putative binding site in the MMP-1 promoter. Results show ZBP-89 is needed for maximal induction of both genes by IL-1ß and TNFα. Binding of both ZBP-89 and NF-κB to both promoters was decreased in the knock-down cells under basal and TNF-induced conditions, and protein interactions between ZBP-89 and NF-κB were suggested. These data provide the first evidence of a role for ZBP-89 in regulation of MMP-1 expression, and suggest the possibility of a larger role for ZBP-89 in inflammation through interactions with NF-κB.