Transcriptome of healthy gingival tissue from edentulous sites in patients with a history of generalized aggressive periodontitis

Background: This study evaluates the transcriptome of healthy gingival tissue from edentulous sites in patients with a history of generalized aggressive periodontitis (GAgP), chronic periodontitis (CP), and in patients with no history of periodontitis (H), using microarray and quantitative reverse transcription polymerase chain reaction (qRT- PCR) analysis. Methods: Healthy gingival tissue from edentulous sites was taken from patients from the GAgP (n = 12), CP (n = 12), and H (n = 12) groups. Initially, total RNA from four tissue samples per group was used in transcriptomic microarray analysis. Differential gene expression (fold-change), gene ontology (GO; biologic process), and pathway analyses were performed. Genes that were differentially expressed and showing a significant role on altered pathways were validated by qRT- PCR analysis on 12 samples per group. Results: In total, 270 probe sets and 50 GO groups were differentially expressed (upregulated or downregulated) between GAgP and H. Natural killer cell receptors and other genes related to the immune system were upregulated in GAgP, whereas genes with functions in neural processes and in proliferation/differentiation of keratinocytes were underexpressed. There were 220 probe sets and 75 GO groups that were differentially expressed when comparing CP and GAgP. CP was characterized by increased expression of genes related to responses to external stimuli and an underexpression of immune system-related genes. qRT- PCR analysis confirmed microarray results, that killer cell immunoglobulin (Ig)-like receptor, two Ig domains and long cytoplasmic tail 4; interleukin-6; and selectin E were more highly expressed in patients from the GAgP group compared with the CP and H groups. Conclusion: This study demonstrates differences in the transcriptome of healthy gingival tissue from edentulous sites in patients with GAgP compared with patients from H or CP groups.