Pathobiont effects on oral mucositis model via 3d bioprinting and organ-on-chip systems

Objectives: Oral mucositis (OM) remains a painful and debilitating complication of cancer therapy, largely due to the lack of effective treatments and physiologically relevant in vitro models. Recent studies implicate microbial dysbiosis—particularly the overabundance of the anaerobic Fusobacterium genus, especially Fusobacterium nucleatum (Fn)—in the pathogenesis and severity of OM. This study aimed to develop an advanced 3D oral mucositis model to investigate the pathogenic mechanisms of Fn and its potential as a therapeutic screening platform. Methods: A three-dimensional (3D) oral epithelial sheet (OES) model was developed using magnetic nanoparticle-assisted bioprinting to assemble human oral epithelial cells into a structured tissue platform. The model was integrated with organ-on-chip microfluidics to simulate dynamic conditions. OES constructs were treated with the chemotherapeutic agent 5-fluorouracil (5-FU), followed by exposure to F. nucleatum . The effects of Fn were assessed through multiple endpoints, including epithelial viability, integrity of cell–cell junctions, pro-inflammatory cytokine secretion, γ-H2AX expression (DNA damage response), activation of nuclear factor erythroid 2–related factor 2 (Nrf2), cell migration, and intracellular calcium flux. Results: Exposure to F. nucleatum significantly reduced epithelial cell viability and disrupted intercellular junction integrity. Fn also inhibited the nuclear translocation of Nrf2, leading to impaired antioxidant response. Additionally, Fn increased pro-inflammatory cytokine secretion and γ-H2AX expression, indicating elevated DNA damage and oxidative stress, while cell migration remained unaffected. Conclusions: Fusobacterium nucleatum exacerbates 5-FU–induced oral mucositis by promoting inflammation, oxidative stress, and epithelial barrier disruption in a 3D organ-on-chip model. This bioengineered system provides a physiologically relevant platform to study host–pathogen interactions in OM and holds promise for preclinical drug screening and mechanistic research on oral mucosal pathobiology.