Background: The chronic inflammatory disease periodontitis is characterized by destruction of periodontal tissue, and involves a complex network of cells, inflammatory mediators and signaling pathways. Despite extensive research, specific genes responsible for periodontitis have not yet been identified. Objectives: The aim of the study was to investigate the whole transcriptome profile in gingival tissue obtained from patients with periodontitis and healthy controls, using RNA-sequencing (RNA-seq). Furthermore, we also aimed to investigate the expression of significantly differentially expressed genes at protein level in gingival tissue. Methods: A total of 127 non-smoking subjects, 64 with periodontitis and 63 healthy controls were included in the study. The mean age of the subjects was 60 ± 14 and consisted of 72 females and 55 males. RNA-seq analysis was performed using RNA extracted from the biopsies. For assessment of the degree of inflammation in gingival tissue, histological and immunohistochemistry staining was performed using, H&E and anti-CD68. Results: An overview of the whole transcriptome was obtained by RNA-seq. The transcriptome analysis revealed a total of 100 significantly (adj p<0.1) differentially expressed genes. Additional analyses of genes expressed in the periodontitis group showed that 70 genes were up-regulated, whereas 30 genes were shown to be down-regulated. The degree of inflammatory cell infiltration and the amount of CD68 positive cells was evaluated by three blinded observers, using a relative scale from 0 to 3, and showed a general trend of higher inflammation in tissue from patients with periodontitis compared to controls. Conclusion: This study provides insight into the transcriptome of gingival tissue from patients with periodontitis compared to healthy controls. Genes that are overexpressed will be further analyzed in order to identify possible markers for periodontitis.
Keywords: Periodontitis, gingival tissue, RNA-seq, transcriptome, differentially expressed