Diffferences in susceptibility of gingival fibroblasts to butyric-acid induced apoptosis

Objectives: We previously reported that human healthy gingival fibroblasts (HGF) rescue butyric acid-induced T-cell apoptosis via the proinflammatory cytokines and cell adhesion molecules, which were produced in fibroblasts stimulated with butyric acid. We also reported that inflamed gingival fibroblasts (IGF) isolated from adult periodontitis patients appear to be highly susceptible to butyric acid-induced apoptosis in a mitochondria- dependent fashion. In this study, we further examined the susceptibility of IGF to butyric acid-induced apoptosis by expression microarray technology and western blot analysis. Methods: Totally eight HGFs were employed in this study; type cell line Gin-1, 3 of HGFs and 4 of IGFs. HGF and IGF were grown in culture medium with or without 5 mM butyric acid. Total RNA was extracted, reverse transcripted and cDNAs were labeled, and hybridized on the DNA array. The whole cell lysate were extracted and apoptosis-related proteins were detected by western blotting and caspase assays. Results: cDNA microarray analysis demonstrated that numerous genetic changes were occurred in IGF compared to HGF before butyric acid-stimulation. Furthermore, by western blot and caspase activity analysis, suppression of Bcl-2, Bcl-x, Fibronectin, Laminin and VLA-2, and increase in JNK and Caspase -3, -4, -8, -9 were noted in IGF. Conclusion: These data strongly suggest that the difference in susceptibility of fibroblasts to bacterial metabolite, butyric acid, relate to tissue destruction and periodontitis. This study was supported by a grant (no. 19390537 ) from the Ministry of Education, Science, Sports and Culture, in Japan.