Spatial Transcriptomics Delineates the Inflammatory Landscape of Human Dental Pulp: Regional Crosstalk and Therapeutic Implications.

This study aimed to investigate the spatial cellular architecture and molecular interactions in healthy and inflamed dental pulp using spatial transcriptomics (Visium HD), to elucidate the pathological mechanisms of pulpitis and identify potential therapeutic targets for vital pulp therapy. Spatial transcriptomic sequencing was performed on dental pulp tissues from two healthy individuals and two pulpitis patients, with integrated analyses including Seurat clustering, cell trajectory inference, GO enrichment, CellphoneDB interaction network modelling and PROGENy pathway activity assessment to compare cellular heterogeneity and signalling regulation. Nine major cell types (fibroblasts, progenitor cells, endothelial cells, neural cells, plasma cells, B cells, T cells, monocytes and macrophages) were identified, and their spatial distribution was mapped. Subclustering and differential expression analysis revealed that fibroblast (e.g., APOL2+/CCN2+) and progenitor cell (e.g., CDK5R1+/CCRL2+) subclusters exacerbated fibrosis and immune activation, while TMPRSS4+/CST5+ fibroblasts were critical for homeostasis. Pro-inflammatory endothelial subclusters (IGHG1+/CXCL13+) expanded, while anti-inflammatory subclusters (SERPINA5+/SERPINA3+) diminished, may lead to vascular-immune imbalance. Upregulation of immunoglobulin genes and downregulation of MBP disrupted neural function, while inflamed pulp showed increased B cells and macrophages, decreased T cells and monocytes. Inflammatory pathways (PI3K, EGFR, TGFβ, MAPK, Oestrogen, NF-κB) were upregulated, with enhanced TGFβ signalling in endothelial cells. Intercellular interaction analysis showed altered APP-CD74 signalling in endothelial-macrophage interactions and disrupted CXCL14-mediated communication between immune and endothelial cells. For the first time, we have identified nine cell populations in dental pulp with their spatial localization and intercellular crosstalk using spatial transcriptomic sequencing technology, and mapped the inflammatory landscape of dental pulp. Cellular remodelling-driven by APP suppression, CXCL14 deficiency and TGFβ activation-is a central mechanism in pulpitis progression. These findings provide a preliminary spatial transcriptomic foundation that may inform the development of targeted strategies for vital pulp therapy.