Characterizing the microbial and inflammatory state within distant clinically healthy tissues in patients with active periodontal disease

/Abstract Periodontitis is one of the most chronic oral inflammatory disease in humans and affects more than 10% of the global population, while gingivitis is estimated to affect more than 46% of all adults aged 30 years or older in the United States alone1, 2. While advances in periodontal research over the past 50 years in both humans and animal models has vastly improved our understanding of the etiology and pathophysiology across the spectrum of this disease3-11, most studies have focused on investigating the severe, chronic, and irreversible form of periodontal disease, periodontitis, often in comparison to other healthy individuals. Critical knowledge gaps remain in our understanding of how inflammation is triggered and maintained during the reversible, intermediary, and most prevalent form of periodontal disease – gingivitis1, 2, 12, 13, and importantly what cell types, functions, and signaling is disrupted leading to further chronic inflammation progression and ultimately periodontitis. To date, several single cell transcriptome (scRNA-seq) studies aimed at resolving active cell types within gingival tissues in health and disease (experimental gingivitis, periodontitis) have been published. However, at the time of this application, no scRNA-seq studies characterizing gingivitis have been published or made available to the broader scientific community – representing a significant knowledge gap. Furthermore, no existing scRNA-seq datasets have aimed to resolve the relationship of active periodontal disease associated bacteria within subgingival plaque to observed active cell expression in adjacent gingival tissues. In this study we seek to employ recent advances in scRNA-seq14 to increase cell recovery and capture underrepresented cell types in current periodontal scRNA-seq datasets (gingivitis and periodontitis), while robustly characterizing the dental plaque microbiota and target chemokines/cytokines in GCF in parallel. This will uniquely allow us to resolve key differential signaling pathways between healthy sites and gingivitis and between gingivitis and periodontitis. In particular, the activity of key cell types (neutrophils, macrophage, mast, natural killer, conventional dendritic, and various T-cells) involved in the activation of enzymatic degradation of periodontal tissues and osteoclast differentiation effecting alveolar bone resorption during periodontitis. Overall, a major thrust of NIH/NIDCR in general is to provide single cell resolution of active inflammatory cell types across tissues. The success of this project and deposition of resulting data will significantly contribute to existing public resources15, 16 and greatly expand current knowledge. Resolving transcriptionally active cell types within gingival tissues, soluble host immunomodulatory signals, and the active bacteria within sites of active inflammation compared to distant clinically healthy tooth sites in the same individual may identify key signaling pathways and regulatory mechanisms for future therapeutic, diagnostic, and mechanistic studies that aim to maintain healthy homeostasis, resolve periodontal inflammation, and prevent periodontal disease progression. Project Number: 1R03DE034443-01A1 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Dental and Craniofacial Research (NIDCR) | Principal Investigator: Kristopher Kerns | Institution: UNIVERSITY OF WASHINGTON, SEATTLE, WA | Award Amount: $311,000 | Activity Code: R03 | Study Section: National Institute of Dental and Craniofacial Research Special Grants Review Committee[DSR] View on NIH RePORTER: https://reporter.nih.gov/project-details/11232648