Toshikazu Yasui

Possible Link between Glycolysis and Apoptosis Induced by Sodium Fluoride

Fluoride has been used to prevent caries in the dentition, but the possible underlying mechanisms of cytotoxicity induction by this compound are still unclear. Since fluoride is known as an inhibitor of glycolytic enzymes, we investigated the possible connection between NaF-induced apoptosis and glycolysis in human promyelocytic leukemia HL-60 cells. NaF-induced apoptotic cell death is characterized by caspase activation, internucleosomal DNA fragmentation, loss of mitochondrial membrane potential, and production of apoptotic bodies. Higher activation of caspases-3 and -9, as compared with that of caspase-8, suggested the involvement of an extrinsic pathway. Utilization of glucose was nearly halted by NaF, whereas that of glutamine was rather enhanced. NaF enhanced the expression of Bad protein, but not that of Bcl-2 and Bax proteins, and reduced HIF-1α mRNA expression. Analysis of these data suggests a possible link between glycolysis and apoptosis.

MAPKs, activator protein‐1 and nuclear factor‐κB mediate production of interleukin‐1β‐stimulated cytokines, prostaglandin E2 and MMP‐1 in human periodontal ligament cells

BACKGROUND AND OBJECTIVE Determination of the interleukin-1 (IL-1) signaling cascades that lead to the production of various inflammatory mediators and catabolic factors may clarify attractive targets for therapeutic intervention for periodontitis. We comprehensively assessed the involvement of MAPKs, activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in IL-1β-induced production of interleukin-6 (IL-6), interleukin-8 (IL-8), prostaglandin E(2) (PGE(2) ) and MMP-1 in human periodontal ligament cells. MATERIAL AND METHODS Human periodontal ligament cells were pretreated with an inhibitor for each of the MAPKs or NF-κB and subsequently treated with IL-1β. Following treatment, phosphorylation of three types of MAPK (ERK, p38 MAPK and c-Jun N-terminal kinase), IκB kinase (IKK) α/β/γ and IκB-α, as well as the DNA binding activity of AP-1 and NF-κB and the production of IL-6, IL-8, PGE(2) and MMP-1, were determined by western blotting, a gel mobility shift assay and ELISA, respectively. RESULTS The three MAPKs, simultaneously activated by IL-1β, mediated the subsequent DNA binding of AP-1 at various magnitudes, while IKKα/β/γ, IκB-α and NF-κB were also involved in the IL-1 signaling cascade. Furthermore, IL-1β stimulated the production of IL-6, IL-8, PGE(2) and MMP-1 via activation of the three MAPKs and NF-κB, because inhibitors of these significantly suppressed the IL-1β-stimulated production of these factors. CONCLUSION Our results strongly suggest that MAPK, AP-1 and NF-κB mediate the IL-1β-stimulated synthesis of IL-6, IL-8, PGE(2) and MMP-1 in human periodontal ligament cells. Therefore, inhibition of activation of MAPK, AP-1 and/or NF-κB may lead to therapeutic effects on progression of periodontitis.

Negative regulation of NaF-induced apoptosis by Bad–CAII complex

Fluoride is used to prevent caries in dentistry. However, its mechanism of cytotoxicity induction is unclear. This study was undertaken to determine whether sodium fluoride (NaF) induces apoptosis in human oral cells and if so, whether Bad protein is involved in the process. NaF showed higher cytotoxicity and apoptosis-inducing activity against human oral squamous cell carcinoma cells (HSC-2) than against human gingival fibroblasts (HGF). Western blot analysis showed that NaF enhanced the expression and dephosphorylation of Bad protein. This study demonstrates for the first time that Bad protein forms a complex with carbonic anhydrase II (CAII), and NaF stimulates the detachment of CAII from the Bad-CAII complex and the replacement by the formation of Bad-Bcl-2 complex. Knockdown of Bad and CAII mRNA by siRNA inhibited and enhanced the NaF-induced caspase activation, respectively. The present study suggests that CAII negatively regulates the NaF-induced apoptosis by forming a complex with Bad.

Therapeutic potential of solubilized nanolignin against oral diseases

Abstract Lignocellulosic biomass is a complex biopolymer that is primarily composed of cellulose, hemicellulose, and lignin. Lignin, the main natural aromatic polymer, has a very complex and complicated structure that depends on the separation method and plant species. Their molecular weights fluctuate largely from monolignols to nanofibers, depending on pH, extraction conditions (pH, temperature, Fe 2+ / 3+ ) and shearing process. Limited digestion of LCC demonstrated the importance of lignin moiety, but not carbohydrate moiety for antihuman-immunodeficiency virus (HIV) activity induction. Dehydrogenation polymers of p -coumaric acid, felluric acid, or caffeic acid showed much higher anti-HIV activity than their respective monomers, suggesting the importance of highly polymerized structures. [ 125 I]-labeled LCC rapidly bound to the virus and reduced its infectivity. Bioavailability of orally administered [ 125 I]-LCC was very low, validating its application through oral mucosa. Alkaline extraction was superior to hot water extraction in recovering anti-HIV activity from green tea, black tea, and oolong tea-leaves and licorice root. Oral intake of alkaline extract of Sasa senanensis Rehder leaf (SE) (OTC drug) and LCC/vitamin C tablet significantly improved the symptoms of lichenoid dysplasia and herpes simplex virus (HSV)-patients, respectively. Use of SE-enriched tooth-paste significantly reduced halitosis. These data suggest the applicability of solubilized nanolignin against various oral diseases.

Functional Evaluation of Sasa Makino et Shibata Leaf Extract as Group III OTC Drug

Kampo Medicines, classified as Group II, are usually available as hot water extracts of more than two different plant species. Recently, the presentation of the detailed compositional analysis by HPLC has become mandatory for the publication of the biological activity of Kampo Medicines. However, we often experience the loss of biological activity of Kampo medicines during the purification steps, thus making it difficult to assign the active princi‐ ples. Herb extracts are classified into Group II and Group III. Three major products of bam‐