A Sialidase-Deficient Porphyromonas gingivalis Mutant Strain Induces Less Interleukin-1β and Tumor Necrosis Factor-α in Epi4 Cells Than W83 Strain Through Regulation of c-Jun N-Terminal Kinase Pathway

Background: Porphyromonas gingivalis is one of the major periodontal pathogens. In a previous study, a mouse abscess model showed that sialidase deficiency of P. gingivalis weakened its virulence, but the mechanism behind this observation remains unknown.Methods: A sialidase-deficient mutant strain (△PG0352) and a complemented strain (com△PG0352) were constructed. Epi4 cells were stimulated by wild-type strain P. gingivalis W83, △PG0352, or com△PG0352. Real-time polymerase chain reaction was carried out to detect expression of virulent genes in P. gingivalis and interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in epi4 cells. Activities of sialidase, gingipains, and lipopolysaccharide (LPS) were compared among the different P. gingivalis strains. Levels of IL-1β and TNF-α in the epi4 cells supernatant were detected by enzyme-linked immunosorbent assay and levels of p38, extracellular signal-regulated kinase, c-Jun N-terminal kinase (JNK), and phospho-c-Jun were detected by western blottin...