Analysis of interleukin-activated human gingival fibroblasts: Modulation of chemokine responses by female hormones

Background: The female sex hormones are known to affect the response of numerous tissues to an immune challenge. Because such hormones normally fluctuate during puberty, pregnancy, and the menstrual cycle, more information about the hormonal modulation of such responses in the oral cavity is needed. Gingival fibroblasts (GF), major components of the oral tissues, are potentially sources for inflammatory mediators. Methods: Macroarrays specific for cytokines and related proteins were used to examine the regulation of gene expression in GF under serum-free, resting conditions, after immune challenge with interleukin-1 beta (IL-1 beta), and in the presence of IL-1 beta plus a progestin, +/- 17 beta-estradiol. Additional studies used enzyme-linked immunosorbent assays (ELISAs) to test for secreted chemokines after the same treatments. Results: Of the 392 genes on the macroarray, 66 were up- or downregulated at least 2-fold relative to the unstimulated control in an average of six different sub-lines. Chemokines represented the largest group (18%) of these regulated genes. Numerous genes whose expression was upregulated by IL-1 beta were modulated downward by IL-1 beta plus progestin, +/- 17 beta-estradiol. Measurements of the secretion of IL-8, a CXC chemokine, and MCP-1, a CC chemokine, confirmed the inhibitory effect of a progestin on these genes. Conclusions: Gingival fibroblasts are active participants in the immune response in the oral cavity, and may potentially produce many chemokine signals after exposure to IL-1 beta. GF can attract neutrophils, monocytes, eosinophils, and fibroblasts to the area of injury, and aid in the wound repair process. The concentration of female sex hormones, especially progestin, may significantly affect these signaling systems.