Single-cell Transcriptomic Atlas of Gingival Mucosa in Type 2 Diabetes

The oral gingival barrier is a constantly stimulated and dynamic environment where homeostasis is often disrupted, resulting in inflammatory periodontal diseases. Type 2 diabetes (T2D), a risk factor for periodontitis, has been reported to be associated with barrier dysfunction, but the effect and underlying mechanism are inconclusive. Herein, we performed single-cell RNA sequencing (scRNA-seq) of gingiva from leptin receptor-deficient (db/db) mice to understand the heterogeneity of gingival barrier in the context of T2D. Periodontal health of control mice is characterized by populations of Krt14+-expressing epithelial cells and Col1a1+-fibroblasts mediating immune homeostasis primarily through the enrichment of innate lymphoid cells. The db/db mice exhibit an impaired gingival barrier with spontaneous periodontal bone loss, and a decreased proportion of epithelial/stromal cells. We further observed stromal, particularly fibroblast immune hyperresponsiveness linked to recruitment of myeloid cell populations in gingiva from T2D mice. Analysis of ligand-receptor interaction pairs suggested inflammatory signaling between fibroblasts and myeloid cells, a main driver of diabetes-induced periodontal damage. Moreover, the “Immune-like” stromal cells contributed to gingival Th17/IL-17 hyperresponsiveness in T2D. Our work reveals transcriptional diversity of stromal cells and interaction with innate immune cells in T2D, and uncovers the “immune-like” fibroblast subsets participating in barrier homeostasis at the diabetic gingiva. Overall design: Gingival single-cell transcriptomic profile of 16-wk-old db/db mice and control mice were generated by sc-RNA sequencing.