Single‐Cell Transcriptomic Landscape of Smoking‐Related Periodontitis

AIM: To characterize the cellular composition and molecular microenvironment of smoking-related periodontitis using single-cell RNA sequencing. MATERIALS AND METHODS: Single-cell RNA sequencing was performed on periodontal tissues from healthy controls (H, n = 2), patients with periodontitis (PD, n = 2), and patients with smoking-related periodontitis (SPD, n = 3). Immunofluorescence validated key gene expression and specific cell subtypes involved in SPD. RESULTS: In periodontal tissues, gingival epithelial cells were the cell type most affected by smoking. Compared with the PD group, the SPD group showed increased CXCL16 secretion and features of cellular senescence. A subset of CXCR6+ regulatory T cells (CXCR6+ Tregs) was identified in SPD and potentially recruited by epithelial cells via the CXCL16-CXCR6 axis. Quantitative Set Analysis for Gene Expression indicated a potential regulatory role of CXCR6+ Tregs in T helper 17 (Th17) differentiation, while intercellular communication and pseudotime analyses suggested that CXCR6+ Tregs may amplify inflammatory responses by activating Th17 cells through the CD2-CD58 interaction. CONCLUSIONS: In SPD, gingival epithelial cells exhibit senescence with increased chemokine secretion. These senescent cells may recruit CXCR6+ Tregs via CXCL16 release, potentially regulating Th17 cell differentiation. These findings provide a molecular basis for understanding SPD pathogenesis.