Lipopolysaccharides-Induced Suppression of Innate-Like B Cell Apoptosis Is Enhanced by CpG Oligodeoxynucleotide and Requires Toll-Like Receptors 2 and 4

Abstract

Innate-like B lymphocytes play an important role in innate immunity in periodontal disease through Toll-like receptor (TLR) signaling. However, it is unknown how innate-like B cell apoptosis is affected by the periodontal infection-associated innate signals. This study is to determine the effects of two major TLR ligands, lipopolysaccharide (LPS) and CpG-oligodeoxynucleotides (CpG-ODN), on innate-like B cell apoptosis. Spleen B cells were isolated from wild type (WT), TLR2 knockout (KO) and TLR4 KO mice and cultured with E. coli LPS alone, P. gingivalis LPS alone, or combined with CpG-ODN for 2 days. B cell apoptosis and expressions of specific apoptosis-related genes were analyzed by flow cytometry and real-time PCR respectively. P. gingivalis LPS, but not E. coli LPS, reduced the percentage of AnnexinV+/7-AAD- cells within IgMhighCD23lowCD43-CD93- marginal zone (MZ) B cell sub-population and IgMhighCD23lowCD43+CD93+ innate response activator (IRA) B cell sub-population in WT but not TLR2KO or TLR4KO mice. CpG-ODN combined with P. gingivalis LPS further reduced the percentage of AnnexinV+/7-AAD- cells within MZ B cells and IRA B cells in WT but not TLR2 KO or TLR4 KO mice. Pro-apoptotic CASP4, CASP9 and Dapk1 were significantly down-regulated in P. gingivalis LPS- and CpG-ODN-treated B cells from WT but not TLR2 KO or TLR4 KO mice. Anti-apoptotic IL-10 was significantly up-regulated in P. gingivalis LPS- and CpG-ODN-treated B cells from WT and TLR2 KO but not TLR4 KO mice. These results suggested that both TLR2 and TLR4 signaling are required for P. gingivalis LPS-induced, CpG-ODN-enhanced suppression of innate-like B cell apoptosis.

Advanced glycation end‐products and Porphyromonas gingivalis lipopolysaccharide increase calprotectin expression in human gingival epithelial cells

“…On the other hand, the expression of TLR2 was enhanced by PgLPS but not by AGE, neither at mRNA nor at protein levels (Figures B and D). Previous studies have shown that PgLPS activates both TLR2 and TLR4 . Under our experimental conditions, however, the TLR4 gene was expressed at very low levels in OBA‐9 cells, and PgLPS did not enhance the expression of TLR4 compared with TLR2 (data not shown).…”

The Toll-like receptor ligand, CpG oligodeoxynucleotides, regulate proliferation and osteogenic differentiation of osteoblast

“…In the past dacades, serveral CpG ODNs have been designed and their roles have been investigated widely [14,15]. However, there were few studies about the relation of CpG ODN on osteogenic differentiation in previous researches.…”

Apoptosis Transcriptional Profile Induced byPorphyromonas gingivalisHmuY

“…Several studies have demonstrated many factors to suppress or inhibit apoptosis, showing the dependence of genes which encode pro- and antiapoptotic proteins in the balance of this process [35, 36]. In the presence of a bacterial challenge, it is possible to observe DNA damage associated with apoptosis and expression of p53, BCL-2 [37], FAS, FASL, and active caspase 3 in gingival tissues [38].…”