Fusobacterium nucleatum dysregulates inflammatory cytokines and NLRP3 inflammasomes in oral cells.

Abstract

This study aimed to clarify the difference in Fusobacterium nucleatum (F. nucleatum) induced inflammatory cytokines and nod-like receptor protein 3 (NLRP3) inflammasomes dysregulation among three periodontal cells. Oral epithelial cells (HIOECs), THP-1 macrophages, and human gingival fibroblasts (HGFs) were exposed to F. nucleatum with/without adenosine triphosphate (ATP) and nigericin (Nig). Cell morphology was assessed by scanning electron microscopy. qRT-PCR, protein microarrays, and bioinformatic methods were used to evaluate the cytokines and their complex interplay. NLRP3 inflammasomes activation was detected by western blotting and ELISA. F. nucleatum adhered to and invaded cells. In HIOECs, F. nucleatum enhanced interleukin (IL)-1α/1β/6/10/13, TNF-α, and interferon (IFN)-γ expression. In THP-1 macrophages, F. nucleatum up-regulated IL-1α/1β/6/10 and TNF-α levels. In HGFs, F. nucleatum increased IL-6 levels. F. nucleatum and ATP synergistically boosted IFN-γ level in THP-1 macrophages and IL-13 level in HGFs. IL-1α/1β/6, and TNF-α served as epicenters of the inflammatory response. Additionally, F. nucleatum activated NLRP3 inflammasomes in HIOECs, and ATP/Nig boosted the activation. F. nucleatum also triggered NLRP3 inflammasomes in THP-1 macrophages, but in HGFs, only NLRP3 and caspase-1 levels were elevated. F. nucleatum infiltrated periodontal supporting cells and dysregulated inflammatory cytokines and NLRP3 inflammasomes.