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Biology subjects

Kerns, K. A.

Publications and source records attributed to Kerns, K. A..

3 recordsLinked to original sources

Paired oral clinical specimens reveal the underlying ecology supporting the emergence of inflammophilic microbiome communities

BackgroundInflammatory oral diseases are associated with reproducible shifts from commensal-dominated microbiota toward pathobiont-enriched communities, yet the ecological mechanisms underlying the emergence of inflammophiles remain poorly understood. This study aims to investigate if host-derived inflammatory environments act as selective pressures that restructure microbial metabolism and community organization during disease progression. MethodsWe performed 16S rRNA gene sequencing of patient-matched pediatric dental plaque and odontogenic abscess specimens to capture microbial community transitions across an inflammatory ecological gradient. Community ecology modeling and inferred metagenomic analyses were used to identify taxa and functional programs associated with commensal and inflammophilic states. ResultsPatient-matched comparisons revealed a reproducible ecological selection gradient linking inflammatory environments to expansion of metabolically specialized inflammophiles and depletion of carbohydrate-utilizing commensals. Commensal-dominated plaque communities exhibited anabolic, carbohydrate-centered metabolic capacity, whereas abscess microbiota were enriched for catabolic metabolism, amino acid fermentation, and antimicrobial resistance, consistent with adaptation to inflammation-driven nutrient landscapes and immune pressure. ConclusionsThese findings support a model in which host inflammation drives ecological restructuring of the oral microbiome toward metabolically adapted inflammophilic communities. Defining the metabolic requirements and selective pressures governing these transitions provides a framework for microbiome-directed therapeutic strategies aimed at restoring ecological stability during inflammatory dysbiosis.

bioinformatics↗

Episymbiotic Saccharibacteria suppresses epithelial immunoactivation through Type IV pili and TLR2 dependent endocytosis

Saccharibacteria are episymbionts that require host-bacteria to grow. They are positively associated with inflammatory diseases within the human microbiome, yet their mechanisms for interacting with the human host and contributing to diseases remain unknown. This study investigated interactions between a Saccharibacterium (Nanosynbacter lyticus), its host-bacteria (Schaalia odontolytica), and oral epithelial cells. The host-bacteria induced proinflammatory cytokines in epithelial cells, while Saccharibacteria were immune silent. Remarkably, Saccharibacteria dampened cytokine responses to host-bacteria during coinfection. This effect was driven by Saccharibacteria-induced clustering of TLR2 receptors, a process likely facilitated by type IV, ultimately leading to reduced TLR2-mediated cytokine signalling. High resolution imaging showed that Saccharibacteria were endocytosed by oral epithelial cells, and colocalized with endosome markers, eventually trafficking to lysosomes. Moreover, a subset of the Saccharibacteria survive endocytosis long-term, and retains their capability to reinfect host-bacteria, highlighting a mechanism for persistence in the oral microbiome and a vital role in mammalian immune system modulation.

immunology↗

Rapamycin rejuvenates oral health in aging mice

Periodontal disease is an age-associated disorder clinically defined by periodontal bone loss, inflammation of the specialized tissues that surround and support the tooth, and microbiome dysbiosis. Currently, there is no therapy for reversing periodontal disease, and treatment is generally restricted to preventive measures or tooth extraction. The FDA-approved drug rapamycin slows aging and extends lifespan in multiple organisms, including mice. Here we demonstrate that short-term treatment with rapamycin rejuvenates the aged oral cavity of elderly mice, including regeneration of periodontal bone, attenuation of gingival and periodontal bone inflammation, and revertive shift of the oral microbiome toward a more youthful composition. This provides a geroscience strategy to potentially rejuvenate oral health and reverse periodontal disease in the elderly. Single Sentence SummaryShort-term treatment with rapamycin reverses periodontal bone loss, attenuates inflammation, and remodels the oral microbiome toward a more youthful state.

pathology↗