Induction of Apoptotic Cell Death by Oral Streptococci in Human Periodontal Ligament Cells

• DOI: 10.3389/fmicb.2021.738047
• Publication Date: 2021-10-14T09:14:19Z
• Authors: Ok-Jin Park; A Reum Kim; Yoon Ju So; Jintaek Im; Hyun Jung Ji; Ki Bum Ahn; Ho Seong Seo; Cheol-Heui Yun; Seung Hyun Han
• Keywords: Streptococcus gordonii; Streptococcus sanguinis; Streptococcus mitis

Initiation and progression of oral infectious diseases are associated with streptococcal species. Bacterial infection induces inflammatory responses together reactive oxygen species (ROS), often causing cell death tissue damage in the host. In present study, we investigated effects streptococci on cytotoxicity ROS production human periodontal ligament (PDL) cells. Streptococcus gordonii showed a dose- time-dependent manner. The might be due to apoptosis since S. increased annexin V-positive cells, was reduced by an inhibitor, Z-VAD-FMK. Other such as mitis, sanguinis, sobrinus also induced apoptosis, whereas mutans did not. All tested except triggered PDL Interestingly, however, streptococci-induced appears ROS-independent, not recovered resveratrol or n-acetylcysteine. Instead, hydrogen peroxide (H2O2) important for cytotoxic most generated H2O2, dramatically catalase. Furthermore, lipoproteins involved cytotoxicity, observed that lipoprotein-deficient mutant less potent than wild-type attenuated anti-TLR2-neutralizing antibody. Indeed, purified from alone were sufficient induce cytotoxicity. Notably, H2O2 but cooperatively when co-treated H2O2. Taken together, these results suggest efficiently cells inducing apoptotic bacterial lipoproteins, which contribute apical periodontitis.