Neutrophil-Derived Oncostatin M Contributes to Endothelial Cell Dysfunction During Treponema denticola Interaction.

Periodontitis (PD) is a common chronic inflammatory condition and a risk factor for cardiovascular diseases (CVD), yet underlying linking mechanisms remain unclear. The cytokine Oncostain M (OSM) is elevated in both PD and CVD and has emerged as a potential mediator linking oral inflammation to vascular dysfunction. Neutrophils represent a prominent source of OSM during PD and OSM production is elevated by the periodontal pathobiont Treponema denticola (Td). This study investigated the role of exogenous and neutrophil-derived OSM in endothelial cell (EC) dysfunction and the contribution of heterogenous oral Treponema species in OSM production. Human aortic endothelial cells (HAoEC) were used to evaluate the effects of exogenous purified OSM and neutrophil-derived OSM on endothelial cell function. Endothelial permeability, neutrophil transmigration, cytokine production, cell activation and junctional integrity were assessed using transwell assays, ELISAs, real-time PCR, immunoblotting and immunofluorescence microscopy. Exogenous OSM significantly increased HAoEC permeability, neutrophil transmigration and promoted endothelial activation; characterized by increased E-selectin, ICAM-1 and IL-6 expression. Mechanistically, OSM activated OSMR-STAT3 signaling and altered organization of VE-cadherin in adherens junctions and decreased expression of occludin in tight-junctions. Heterogenous oral Treponema species promote OSM production from mouse and human neutrophils in vitro and in vivo using a mouse air pouch model of infection. T. denticola most robustly induced OSM release, likely independent of prominent virulence factors dentilisin and Msp. Co-culture model experiments revealed conditioned media from T. denticola-stimulated neutrophils promoted endothelial cell permeability and IL-6 while reducing endothelial nitric oxide synthase (eNOS) production. These effects were abolished by antibody neutralization of OSM, supporting a casual role of neutrophil-derived OSM. Overall, these findings provide mechanistic insight into putative links between PD and adverse cardiovascular events and identify OSM signaling as critical mediator in inflammation-driven endothelial dysfunction.