Irsogladine maleate inhibits Porphyromonas gingivalis‐mediated expression of toll‐like receptor 2 and interleukin‐8 in human gingival epithelial cells. (20th September 2014)

• Record Type: Journal Article
• Authors: Savitri, I. J.; Ouhara, K.; Fujita, T.; Kajiya, M.; Miyagawa, T.; Kittaka, M.; Yamakawa, M.; Shiba, H.; Kurihara, H.
• Is Part Of: Journal of periodontal research. Volume 50:Number 4(2015:Aug.)
• Page Start: 486
• Page End: 493
• Publication Date: 2014-09-20
• Subjects: Periodontics -- Periodicals; 617.632
• DOI: 10.1111/jre.12231
• Languages: English
• ISSNs: 0022-3484

Abstract

<abstract abstract-type="main" id="jre12231-abs-0001"> <title>Abstract</title> <sec id="jre12231-sec-0001" sec-type="section"> <title>Background and Objective</title> <p>Periodontitis is an infectious disease caused by an interaction between the host and periodontopathogenic bacteria. Regulating the immune response in human gingival epithelial cells (HGEC) may contribute to the prevention of periodontitis. Irsogladine maleate (IM) has previously been shown to regulate inflammation and the cell–cell junctional barrier in HGEC. In addition to these functions, control of bacterial recognition is important for preventing inflammation in periodontal tissue. Innate immunity in gingival epithelium is the first line of defense and plays a crucial role against bacterial challenge. Therefore, the effect of IM on regulating toll‐like receptor 2 (TLR2), which is part of the innate immunity, was determined in this study.</p> </sec> <sec id="jre12231-sec-0002" sec-type="section"> <title>Material and Methods</title> <p>OBA‐9, an immortalized human gingival epithelial cell line, and primary cultured HGEC were used in this study. Real‐time PCR and western blotting were performed in OBA‐9 or HGEC stimulated with whole cells of <italic>Porphyromonas gingivalis</italic> or with lipopolysaccharide (LPS) derived from <italic>P. gingivalis</italic> (PgLPS) in the presence or absence of IM to determine expression of <italic>TLR2 </italic>mRNA and production of TLR2 protein. Small interfering RNA (siRNA) against TLR2 was transfected into OBA‐9 to clarify the association between the induction of TLR2 and interleukin‐8 (IL‐8) production.</p> </sec> <sec id="jre12231-sec-0003" sec-type="section"> <title>Results</title> <p>The addition of IM into <italic>P. gingivalis</italic> or PgLPS‐induced OBA‐9 suppressed IL‐8 production (<italic>p</italic> < 0.01). The addition of IM also abolished the induction of TLR2 by <italic>P. gingivalis</italic> or PgLPS in OBA‐9 and primary cultured HGEC (<italic>p</italic> < 0.01). The suppressive effect of IM on the induction of TLR2 was also confirmed by immunohistostaining. Stimulation with peptidoglycan, a specific ligand for TLR2, suppressed the expression of toll‐like receptor 4 (<italic>TLR4</italic>) mRNA in the presence of IM (<italic>p</italic> < 0.01). However, LPS derived from <italic>Escherichia coli</italic>, a ligand for TLR4, did not induce the expression of <italic>TLR2 </italic>mRNA. The PgLPS‐induced expression of <italic>TLR4 </italic>mRNA was abolished by IM. Knockdown of TLR2 by siRNA transfection resulted in a weaker response of induction of <italic>IL8 </italic>mRNA in <italic>P. gingivalis</italic> or PgLPS‐stimulated OBA‐9.</p> </sec> <sec id="jre12231-sec-0004" sec-type="section"> <title>Conclusion</title> <p>These results suggest that IM suppresses the induction of IL‐8 production by regulating increased levels of TLR2.</p> </sec> </abstract>