Single-cell transcriptomic analysis reveals fibroblast state-specific remodeling of purinergic signaling in diabetic gingiva

Diabetes mellitus increases the risk and severity of periodontitis by disrupting periodontal mucosa homeostasis and promoting sustained chronic inflammation. Gingival fibroblasts are central regulators of periodontal integrity through extracellular matrix remodeling, immune modulation, and tissue repair. Purinergic signaling is an evolutionarily conserved pathway that regulates cellular metabolism and inflammatory responses, yet its role across distinct gingival fibroblast states in diabetes remains poorly understood. To address this gap, a publicly available single-cell RNA sequencing (scRNA-seq) dataset from wild-type (WT) and diabetic db/db mouse gingival tissue was analyzed. Fibroblasts were reclustered to identify transcriptionally distinct states, and genes associated with extracellular nucleotide signaling, adenosine signaling, ATP release, and inflammasome-associated pathways, including those related to Nlrp3 inflammasome. Genes were evaluated using differential expression, dot plots, UMAP feature plots, and state-specific log₂ fold-change analyses. Four transcriptionally distinct fibroblast states were identified. Diabetic gingiva exhibited an expansion of the inflammatory fibroblast state accompanied by a reduction in ECM remodeling fibroblasts. Genes associated with extracellular nucleotide metabolism and adenosine signaling showed fibroblast state-specific expression patterns, including diabetes-associated differences in Nt5e (CD73), Entpd1 (CD39), and Enpp1 expressions. The adenosine receptor genes Adora2a and Adora2b were expressed at comparatively low levels. Genes associated with ATP release, including connexin-43 (Gja1) and pannexin-1 channels (Panx1), also displayed distinct state-specific expression patterns. Canonical inflammasome-associated genes were generally expressed at low levels, with Nek7 showing the highest overall expression and Casp11 exhibiting state-specific differences in expression, including a higher expression in selected diabetic fibroblast states. These findings identify an expansion of inflammatory fibroblasts in diabetic gingiva and characterize diabetes-associated changes in the expression of genes involved in extracellular nucleotide and nucleoside signaling, ATP release, and inflammasome-associated pathways that vary across fibroblast states.