Gene expression profiling of periodontitis-affected gingival tissue by spatial transcriptomics

TLDR

Periodontitis is a common chronic inflammatory disease of the periodontium that can lead to tooth loss. The study aimed to characterize and localize gene expression in periodontitis‑affected gingival tissue using spatial transcriptomics combined with histology. Spatial transcriptomics was applied to periodontal tissue, integrating RNA sequencing with histological analysis to quantify and localize gene expression. Distinct gene‑expression clusters were identified in periodontitis‑affected gingival tissue, with 92 genes up‑regulated in inflamed connective tissue—particularly IGLL5, SSR4, MZB1, and XBP1—which were validated by qPCR and immunohistochemistry, providing new insights into periodontitis pathogenesis.

Abstract

Abstract Periodontitis is a highly prevalent chronic inflammatory disease of the periodontium, leading ultimately to tooth loss. In order to characterize the gene expression of periodontitis-affected gingival tissue, we have here simultaneously quantified and localized gene expression in periodontal tissue using spatial transcriptomics, combining RNA sequencing with histological analysis. Our analyses revealed distinct clusters of gene expression, which were identified to correspond to epithelium, inflamed areas of connective tissue, and non-inflamed areas of connective tissue. Moreover, 92 genes were identified as significantly up-regulated in inflamed areas of the gingival connective tissue compared to non-inflamed tissue. Among these, immunoglobulin lambda-like polypeptide 5 ( IGLL5 ), signal sequence receptor subunit 4 ( SSR4 ), marginal zone B and B1 cell specific protein ( MZB1 ), and X-box binding protein 1 ( XBP1 ) were the four most highly up-regulated genes. These genes were also verified as significantly higher expressed in gingival tissue of patients with periodontitis compared to healthy controls, using reverse transcription quantitative polymerase chain reaction. Moreover, the protein expressions of up-regulated genes were verified in gingival biopsies by immunohistochemistry. In summary, in this study, we report distinct gene expression signatures within periodontitis-affected gingival tissue, as well as specific genes that are up-regulated in inflamed areas compared to non-inflamed areas of gingival tissue. The results obtained from this study may add novel information on the genes and cell types contributing to pathogenesis of the chronic inflammatory disease periodontitis.