Faculty Profiles - OMORI Kazuhiro

Papers - OMORI Kazuhiro

Division display 21 - 40 of about 46 ／ All the affair displays >>

Antimicrobial and antibiofilm effects of abietic acid on cariogenic Streptococcus mutans Reviewed

Yuki Ito, Takashi Ito, Keisuke Yamashiro, Fumi Mineshiba, Kimito Hirai, Kazuhiro Omori, Tadashi Yamamoto, Shogo Takashiba

Odontology 108 ( 1 ) 57 - 65 2020.1

Publishing type：Research paper (scientific journal)

© 2019, The Society of The Nippon Dental University. Dental caries is a type of oral microbiome dysbiosis and biofilm infection that affects oral and systemic conditions. For healthy life expectancy, natural bacteriostatic products are ideal for daily and lifetime use as anti-oral infection agents. This study aimed to evaluate the inhibitory effects of abietic acid, a diterpene derived from pine rosin, on the in vitro growth of cariogenic bacterial species, Streptococcus mutans. The effective minimum inhibitory concentration of abietic acid was determined through observation of S. mutans growth, acidification, and biofilm formation. The inhibitory effects of abietic acid on the bacterial membrane were investigated through the use of in situ viability analysis and scanning electron microscopic analysis. Cytotoxicity of abietic acid was also examined in the context of several human cell lines using tetrazolium reduction assay. Abietic acid was found to inhibit key bacterial growth hallmarks such as colony forming ability, adenosine triphosphate activity (both planktonic and biofilm), acid production, and biofilm formation. Abietic acid was identified as bacteriostatic, and this compound caused minimal damage to the bacterial membrane. This action was different from that of povidone-iodine or cetylpyridinium chloride. Additionally, abietic acid was significantly less cytotoxic compared to povidone-iodine, and it exerted lower toxicity towards epithelial cells and fibroblasts compared to that against monocytic cells. These data suggest that abietic acid may prove useful as an antibacterial and antibiofilm agent for controlling S. mutans infection.

DOI： 10.1007/s10266-019-00456-0

Microbiome composition comparison in oral and atherosclerotic plaque from patients with and without periodontitis Reviewed

Daichi Isoshima, Keisuke Yamashiro, Kazuyuki Matsunaga, Makoto Taniguchi, Takehiro Matsubara, Shuta Tomida, Shinzo Ota, Michiyoshi Sato, Yutaka Shimoe, Tatsuo Kohriyama, Zulema Arias, Kazuhiro Omori, Tadashi Yamamoto, Shogo Takashiba

Odontology 2020

Publishing type：Research paper (scientific journal)

© 2020, The Society of The Nippon Dental University. There is no conclusive evidence regarding a causal relationship between periodontitis and atherosclerosis. In this study, we examined the microbiome in the oral cavity and atheromatous plaques from atherosclerosis patients with or without periodontitis to investigate the role of oral bacteria in the formation of atheromatous plaques. We chose four patients with and without periodontitis, who had undergone carotid endarterectomy. Bacterial samples were extracted from the tongue surface, from periodontal pocket (during the oral examination), and from the atheromatous plaques (APs). We investigated the general and oral conditions from each patient and performed next-generation sequencing (NGS) analysis for all bacterial samples. There were no significant differences between both groups concerning general conditions. However, the microbiome patterns of the gingival pocket showed differences depending on the absence or presence of periodontitis, while those of the tongue surface were relatively similar. The microbiome pattern of the atheromatous plaques was entirely different from that on the tongue surface and gingival pocket, and oral bacteria were seldom detected. However, the microbiome pattern in atheromatous plaques was different in the presence or absence of periodontitis. These results suggested that oral bacteria did not affect the formation of atheromatous plaques directly.

DOI： 10.1007/s10266-020-00524-w

Acceleration of bone regeneration of horizontal bone defect in rats using collagen-binding basic fibroblast growth factor combined with collagen scaffolds Reviewed

Shin Nakamura, Takashi Ito, Kentaro Okamoto, Takehiko Mima, Kentaro Uchida, Yasir D. Siddiqui, Masahiro Ito, Masako Tai, Keisuke Okubo, Keisuke Yamashiro, Kazuhiro Omori, Tadashi Yamamoto, Osamu Matsushita, Shogo Takashiba

Journal of Periodontology 90 ( 9 ) 1043 - 1052 2019.9

Publishing type：Research paper (scientific journal)

© 2019 The Authors. Journal of Periodontology published by Wiley Periodicals, Inc. on behalf of American Academy of Periodontology Background: Basic fibroblast growth factor (bFGF) has been applied for periodontal regeneration. However, the application depends on bone defect morphology because bFGF diffuses rapidly from defect sites. In a previous study, collagen-binding bFGF (CB-bFGF) has been shown to enhance bone formation by collagen-anchoring in the orthopedic field. The aim of this study is to demonstrate the efficacy of CB-bFGF with collagen scaffolds in bone regeneration of horizontal bone defect. Methods: Cell proliferation activity and collagen binding activity of CB-bFGF was confirmed by WST-8 assay and collagen binding assay, respectively. The retention of CB-bFGF in the collagen sheet (CS) was measured by fluorescence imaging. The rat horizontal alveolar bone defect model was employed to investigate the efficacy of CB-bFGF with collagen powder (CP). After 4 and 8 weeks, the regenerative efficacy was evaluated by microcomputed tomography, histological, and immunohistochemical analyses. Results: CB-bFGF had a comparable proliferation activity to bFGF and a collagen binding activity. CB-bFGF was retained in CS longer than bFGF. At 8 weeks postoperation, bone volume, bone mineral content, and new bone area in CB-bFGF/CP group were significantly increased compared with those in other groups. Furthermore, epithelial downgrowth was significantly suppressed in CB-bFGF/CP group. At 4 weeks, the numbers of osteocalcin, proliferating cell nuclear antigen, and osteopontin-positive cells at the regeneration site in CB-bFGF/CP group were greater than those in other groups. Conclusions: CB-bFGF/CP effectively promoted bone regeneration of horizontal bone defect possibly by sustained release of bFGF. The potential of CB-bFGF composite material for improved periodontal regeneration in vertical axis was shown.

DOI： 10.1002/JPER.18-0674

Resolvin D2 Induces Resolution of Periapical Inflammation and Promotes Healing of Periapical Lesions in Rat Periapical Periodontitis. Reviewed

Siddiqui YD, Omori K, Ito T, Yamashiro K, Nakamura S, Okamoto K, Ono M, Yamamoto T, Van Dyke TE, Takashiba S

Frontiers in immunology 10 307 2019

Induction of migration of periodontal ligament cells by selective regulation of integrin subunits. Reviewed

Kawamura M, Yamamoto T, Yamashiro K, Kochi S, Yoshihara-Hirata C, Ideguchi H, Aoyagi H, Omori K, Takashiba S

Journal of cellular and molecular medicine 23 ( 2 ) 1211 - 1223 2018.12

Publishing type：Research paper (scientific journal)

© 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine. The recruitment of tissue-resident stem cells is important for wound regeneration. Periodontal ligament cells (PDL cells) are heterogeneous cell populations with stemness features that migrate into wound sites to regenerate periodontal fibres and neighbouring hard tissues. Cell migration is regulated by the local microenvironment, coordinated by growth factors and the extracellular matrix (ECM). Integrin-mediated cell adhesion to the ECM provides essential signals for migration. We hypothesized that PDL cell migration could be enhanced by selective expression of integrins. The migration of primary cultured PDL cells was induced by platelet-derived growth factor-BB (PDGF-BB). The effects of blocking specific integrins on migration and ECM adhesion were investigated based on the integrin expression profiles observed during migration. Up-regulation of integrins α3, α5, and fibronectin was identified at distinct localizations in migrating PDL cells. Treatment with anti-integrin α5 antibodies inhibited PDL cell migration. Treatment with anti-integrin α3, α3-blocking peptide, and α3 siRNA significantly enhanced cell migration, comparable to treatment with PDGF-BB. Furthermore, integrin α3 inhibition preferentially enhanced adhesion to fibronectin via integrin α5. These findings indicate that PDL cell migration is reciprocally regulated by integrin α3-mediated inhibition and α5-mediated promotion. Thus, targeting integrin expression is a possible therapeutic strategy for periodontal regeneration.

DOI： 10.1111/jcmm.14023

Fungal metabolite (+)-terrein suppresses IL-6/sIL-6R-induced CSF1 secretion by inhibiting JAK1 phosphorylation in human gingival fibroblasts. Reviewed International journal

Satoshi Yamamoto, Kazuhiro Omori, Hiroki Mandai, Masaaki Nakayama, Saki Nakagawa, Hiroya Kobayashi, Tadashi Kunimine, Hiroshi Yoshimura, Kyosuke Sakaida, Hidefumi Sako, Soichiro Ibaragi, Tadashi Yamamoto, Hiroshi Maeda, Seiji Suga, Shogo Takashiba

Heliyon 4 ( 11 ) e00979 2018.11

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Control of bacterial infection-induced inflammatory responses is one of the effective therapeutic approaches of periodontal diseases. Natural products such as lipid mediators and metabolites from microorganisms have been used for decreasing inflammation. We previously reported that (+)-terrein inhibited activation of STAT3 and ERK1/2 in interleukin-6 (IL-6) signaling cascade, leading to prevent vascular endothelial growth factor (VEGF) secretion in human gingival fibroblasts (HGFs). However, little is still known about the role of (+)-terrein on inflammatory responses. In this study, we provided the possibility of novel action that (+)-terrein inhibits activation of Janus-activated kinase 1 (JAK1), which has a central function in IL-6 signaling cascade, and alters expression of mRNAs and proteins induced by IL-6/soluble IL-6 receptor (sIL-6R) stimulation in HGFs. First, we performed PCR array to examine IL-6/sIL-6R-induced mRNA expression, and then expression of mRNA and protein of colony stimulating factor-1 (CSF1) and VEGF were clearly determined by quantitative RT-PCR and ELISA, respectively. Treatment with (+)-terrein suppressed expression of mRNA and protein of CSF1 and VEGF by IL-6/sIL-6R stimulation. Next, to test the effect of (+)-terrein on IL-6/sIL-6R signaling cascade, we demonstrated whether (+)-terrein affects phosphorylation of JAK1 and its downstream proteins, Akt and SHP-2. Western blotting revealed that (+)-terrein inhibited IL-6/sIL-6R-induced phosphorylation of JAK1, Akt, and SHP-2. Therefore, (+)-terrein suppresses IL-6/sIL-6R-induced expression of CSF1 and VEGF via inhibition of JAK1, Akt, and SHP-2. Based on our results, we suggest that (+)-terrein is a candidate compound for anti-inflammatory effect associated with IL-6 signaling.

DOI： 10.1016/j.heliyon.2018.e00979

A novel, nontoxic iron chelator, super-polyphenol, effectively induces apoptosis in human cancer cell lines. Reviewed International journal

Toshiaki Ohara, Yasuko Tomono, Xing Boyi, Sun Yingfu, Kazuhiro Omori, Akihiro Matsukawa

Oncotarget 9 ( 67 ) 32751 - 32760 2018.8

Language：English Publishing type：Research paper (scientific journal)

Iron chelation therapy is the main treatment for iron overload disease. Iron chelators were recently reported to be useful for cancer therapy; however, they cause side effects that make them difficult to use in some cancer patients. Thus, a novel oral iron chelator, super-polyphenol (SP), was developed for cancer therapy to decrease the side effects. SP is either water soluble or insoluble, and has different isoforms according to the number of side chains. Of these isoforms, water-soluble SP6 and SP10 appear to be the best candidates, as they have the strongest chelating abilities. In this study, we focused on the usefulness and safety of SP6 and SP10 as anti-cancer drugs, and examined their anti-cancer effects and toxicity. The results showed that SP6 and SP10 inhibited cancer cell proliferation by inducing apoptosis in HCT116, HSC-2, A549, and MCF-7 cancer cells. SP10 also inhibited tumor growth in an HCT116 xenograft model. SP6 and SP10 had no acute toxicities. An intravenous injection test revealed that SP6 and SP10 had better safety profiles than the iron chelator deferoxamine. In conclusion, SP is a novel oral iron chelator with anti-cancer effects and few adverse side effects. This is the first report of SP in the literature.

DOI： 10.18632/oncotarget.25973

The KCNQ1 gene polymorphism as a shared genetic risk for rheumatoid arthritis and chronic periodontitis in Japanese adults: A pilot case-control study. Reviewed International journal

Tetsuo Kobayashi, Jun-Ichi Kido, Yuichi Ishihara, Kazuhiro Omori, Satoshi Ito, Takato Matsuura, Takashi Bando, Jun Wada, Akira Murasawa, Kiyoshi Nakazono, Akio Mitani, Shogo Takashiba, Toshihiko Nagata, Hiromasa Yoshie

Journal of periodontology 89 ( 3 ) 315 - 324 2018

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: A number of studies have suggested a bidirectional relationship of periodontitis with rheumatoid arthritis (RA) and type 2 diabetes mellitus (T2DM). However, the genetic factors that underlie these relationships have not been elucidated. METHODS: We conducted a multicenter case-control study that included 185 patients with RA and chronic periodontitis (CP), 149 patients with T2DM and CP, 251 patients with CP, and 130 systemically and periodontally healthy controls from a cohort of Japanese adults to assess the shared genetic risk factors for RA and CP as well as for T2DM and CP. A total of 17 candidate single nucleotide polymorphisms (SNPs) associated with RA, T2DM, and CP were genotyped. RESULTS: Multiple logistic regression analyses revealed that the KCNQ1 rs2237892 was significantly associated with comorbidity of RA and CP (P = 0.005) after adjustment for age, sex, and smoking status. The carriers of the T allele among patients with RA and CP showed significantly higher disease activity scores including 28 joints using C-reactive protein values than the non-carriers (P = 0.02), although the age, female percentage, and smoking status were comparable. Other SNPs were not associated with comorbidity of RA and CP, T2DM and CP, or susceptibility to CP. CONCLUSION: The results of the present pilot study suggest for the first time that the KCNQ1 rs2237892 may constitute a shared genetic risk factor for RA and CP, but not for T2DM and CP in Japanese adults.

DOI： 10.1002/JPER.17-0412

Assessment of pathogenesis of infective endocarditis by plasma IgG antibody titer test against periodontal bacteria. Reviewed International journal

Isoshima D, Yamashiro K, Matsunaga K, Shinobe M, Nakanishi N, Nakanishi I, Omori K, Yamamoto T, Takashiba S

Clinical Case Reports 5 ( 10 ) 1580 - 1586 2017.10

IS1598 (IsPg4) distributed to abscess-forming strains of Porphyromonas gingivalis may enhance virulence through upregulation of nrdD-like gene expression Reviewed

Norihiro Sonoi, Hiroshi Maeda, Toshimitsu Murauchi, Tadashi Yamamoto, Kazuhiro Omori, Susumu Kokeguchi, Koji Naruishi, Shogo Takashiba

New Microbiologica 41 ( 1 ) 52 - 60 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：Luigi Ponzio e figlio Editori

An insertion sequence, IS1598 (IsPg4) has been found in virulent strains of Porphyromonas gingivalis in a murine abscess model. The present study was performed to investigate the effects of genetic rearrangements by IS1598 on the phenotypic characteristics of the virulent strains. For this purpose, we searched for a common insertion site of IS1598 among the virulent strains. Through cloning and database search, a common insertion site was identified beside an nrdD-like gene in the virulent FDC 381, W83 and W50 strains. In this region, predicted promoters of the nrdD-like gene and IS1598 are located in tandem, and accumulation of nrdD-like gene mRNA was 5-fold higher in virulent strains (W83, W50, FDC 381) than avirulent strains (ATCC33277, SU63, SUNY1021, ESO59 without IS1598). The role of the nrdD-like gene in virulence of P. gingivalis was investigated by constructing a nrdD-deficient mutant. In the murine abscess model, the parental W83 strain produced necrotic abscesses, while the nrdD-deficient mutant had almost lost this ability. Insertion of IS1598 into the nrdD-like gene promoter region may be related to the phenotypic differences in virulence among P. gingivalis strains through upregulation of the expression of this gene.

新たな糖尿病合併症に迫る糖尿病患者にとっての歯周病治療を再考する

大森一弘, 高柴正悟

糖尿病合併症 30 ( 2 ) 198 - 201 2016.7

Synthetic Terrein Inhibits Progression of Head and Neck Cancer by Suppressing Angiogenin Production Reviewed

Akane Shibata, Soichiro Ibaragi, Hiroki Mandai, Toki Tsumura, Koji Kishimoto, Tatsuo Okui, Nur Mohammad Monsur Hassan, Tsuyoshi Shimo, Kazuhiro Omori, Guo-Fu Hu, Shogo Takashiba, Seiji Suga, Akira Sasaki

ANTICANCER RESEARCH 36 ( 5 ) 2161 - 2168 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：INT INST ANTICANCER RESEARCH

Background/Aim: Head and neck cancers are the fifth most common cancer type worldwide, affecting more than half a million patients annually. Development of effective therapeutic drugs is, therefore, required for this type of disease. This study assessed the effects of synthetic terrein on head and neck cancer. Materials and Methods: Synthetic terrein was prepared by using the modified Altenhach's procedure. The effect of synthetic terrein on cell proliferation of head and neck cancer cells and HUVECs was assessed. Angiogenin secretion and ribosome biogenesis were examined by ELISA and silver staining of the nucleolar organizer region. A mouse xenograft model was prepared by inoculating mice with suspensions of cells of the human head and neck cancer cell line OSC-19 subcutaneously into the dorsal region of each mouse. Ki-67, CD31 and angiogenin expression in xenografted tumors was examined by immunohistochemistry. Results: Synthetic terrein inhibited the growth of various head and neck cancer cells. In addition, an in vivo experiment revealed that synthetic terrein inhibited a xenograft tumor growth in athymic mice. Immunohistochemical analysis revealed that expression of Ki-67, CD31 and ANG was down-regulated in synthetic terrein-treated tumors, compared to controls. Synthetic terrein suppressed the ANG secretion and ribosome biogenesis in cancer cells, and cell proliferation in vascular endothelial cells. Conclusion: The mechanism underlying the anti-tumor effects of synthetic terrein against head and neck cancer consists of the inhibition of both tumor cell proliferation and angiogenesis via the suppression of ANG production.

【糖尿病と外科-併発症治療の最前線】糖尿病患者に対する医科歯科連携推進の課題

大森一弘, 高柴正悟

糖尿病診療マスター 14 ( 4 ) 295 - 298 2016.4

Gingival overgrowth caused by vitamin C deficiency associated with metabolic syndrome and severe periodontal infection: a case report. Reviewed International journal

Omori K, Hanayama Y, Naruishi K, Akiyama K, Maeda H, Otsuka F, Takashiba S

Clinical Case Reports 2 ( 6 ) 286 - 295 2014.12

Authorship：Lead author Language：English

It has been suggested that vitamin C deficiency/scurvy is associated with gingival inflammatory changes; however, the disorder is very infrequently encountered in the modern era. Here, we report a case of extensive gingival overgrowth caused by vitamin C deficiency associated with metabolic syndrome and severe periodontal infection.

DOI： 10.1002/ccr3.114

Synthetic (+)-terrein suppresses interleukin-6/soluble interleukin-6 receptor induced-secretion of vascular endothelial growth factor in human gingival fibroblasts Reviewed

Hiroki Mandai, Kazuhiro Omori, Daisuke Yamamoto, Toki Tsumura, Kyouta Murota, Satoshi Yamamoto, Koichi Mitsudo, Soichiro Ibaragi, Akira Sasaki, Hiroshi Maeda, Shogo Takashiba, Seiji Suga

BIOORGANIC & MEDICINAL CHEMISTRY 22 ( 19 ) 5338 - 5344 2014.10

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

Interleukin (IL)-6 is a proinflammatory cytokine that performs a wide variety of biological functions, including important roles in the progression of chronic inflammatory diseases such as periodontal disease. (+)-Terrein, a secondary bioactive fungal metabolite isolated from Aspergillus terreus, has various biological activities; however, its anti-inflammatory effects are still unknown. The purpose of this study was to examine the effect of synthetic (+)-terrein on IL-6 signaling and related protein production in human gingival fibroblasts. To our knowledge, this study is the first to report that synthetic (+)-terrein is not cytotoxic at concentrations less than 20 mu M and suppresses IL-6/soluble IL-6 receptor (sIL-6R)-induced phosphorylation of signal transducer and activator of transcription-3, extracellular signal-regulated kinase 1/2, and c-jun N-terminal kinase 1/2-signaling proteins that are downstream of IL-6 signaling. In addition, synthetic (+)-terrein suppresses IL-6/sIL-6R-induced vascular endothelial growth factor (VEGF) secretion in a concentration-dependent manner (p < 0.01). These data suggest that synthetic (+)-terrein has potential anti-IL-6 signaling activity and suppresses VEGF-associated inflammatory disease progression. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2014.07.047

Serum antibody response to group II chaperonin from Methanobrevibacter oralis and human chaperonin CCT Reviewed

Kimito Hirai, Hiroshi Maeda, Kazuhiro Omori, Tadashi Yamamoto, Susumu Kokeguchi, Shogo Takashiba

PATHOGENS AND DISEASE 68 ( 1 ) 12 - 19 2013.6

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Both group I (HSP60) and group II (CCT) chaperonins are targets of autoantibodies. Autoimmune reactions to HSP60 have been well characterized, while immune reactions to group II chaperonin have not been clarified. Methanobrevibacter oralis is a suspected periodontal pathogen with group II chaperonin. In this study, serum responses to M.oralis chaperonin, human HSP60, and CCT subunits were examined using sera from patients with periodontitis and autoimmune diseases. In comparison with healthy controls, periodontitis patients showed significantly higher responses to CCT4 and CCT8 on dot blot analysis. Signals for CCT3 and CCT8 in autoimmune disease patients were significantly higher than in controls. Significant differences were also demonstrated by Western blotting in anti-CCT4 response in both patient groups. All subjects showed strong reactivity to M.oralis chaperonin and faint signals to human HSP60. Autoantibodies were raised against CCT rather than HSP60; and CCT3, CCT4, and CCT8 were shown to be the main targets. Host immune systems may be frequently exposed to chaperonins of Archaea in various habitats. Although further studies of the cross-reactivity between M.oralis chaperonin and human CCT are required, anti-CCT autoantibodies may be involved in the pathogenesis of periodontitis and autoimmune diseases.

DOI： 10.1111/2049-632X.12041

IMMUNE RESPONSES TO PORPHYROMONAS GINGIVALIS INFECTION SUPPRESS SYSTEMIC INFLAMMATORY RESPONSE IN EXPERIMENTAL MURINE MODEL Reviewed

K. Naruishi, K. Omori, H. Maeda, N. Sonoi, K. Funakoshi, K. Hirai, M. Ishii, K. Kubo, H. Kobayashi, T. Tomiyama, D. Yamamoto, I. Tanimoto, K. Kunimatsu, S. Takashiba

JOURNAL OF BIOLOGICAL REGULATORS AND HOMEOSTATIC AGENTS 25 ( 2 ) 195 - 202 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：BIOLIFE SAS

Periodontitis is localized infectious disease caused by periodontopathic bacteria such as Porphyromonas gingivalis (T: gingivalis), and the severity correlates to significance of immune responses. Recently, it has been reported that periodontitis is associated with the development of systemic disease such as diabetes and atherosclerosis because of increasing invasion of oral pathogens to the circulation. However, the association between local and systemic infectious responses is still unclear. In the present study, we examined the differences of biological responses in animals with or without bacterial infection. After Balb/c mice were infected subcutaneously with live P gingivalis W83, serum, skin and liver were collected according to experimental protocol. The skin and liver tissues were observed pathologically by haematoxylin-eosin staining, and serum IL-6 levels were measured using ELISA method. Throughout the experimental period, conditions of the mice were observed continuously. As expected, severe infiltration of leukocytes were observed at inflamed skin corresponding to the number of bacterial challenges. Although no inflammatory appearance of skin was observed, serum IL-6 levels were increased dramatically (P < 0.01, Student's t-test) and liver tissues were injured in the mice without bacterial challenge. Interestingly, although severe inflammatory appearance of the skin was observed, serum IL-6 levels were not increased and no inflammatory responses were observed in the liver of the 3-times bacterially challenged group. Importantly, immunoglobulin G against P gingivalis W83 was detected in the blood of mice with 3-times bacterial challenge corresponding to improvement of weight loss and survival. In conclusion, although multiple infections develop severe localized inflammation, the immune system should be sufficient to protect the systemic inflammatory responses.

Diabetes-Induced Oxidative Stress Is Mediated by Ca2+-Independent Phospholipase A2 in Neutrophils Reviewed

Srinivas Ayilavarapu, Alpdogan Kantarci, Gabrielle Fredman, Oya Turkoglu, Kazuhiro Omori, Hongsheng Liu, Tomoyuki Iwata, Motohiko Yagi, Hatice Hasturk, Thomas E. Van Dyke

JOURNAL OF IMMUNOLOGY 184 ( 3 ) 1507 - 1515 2010.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC IMMUNOLOGISTS

Neutrophils from people with poorly controlled diabetes present a primed phenotype and secrete excessive superoxide. Phospholipase A(2) (PLA(2))-derived arachidonic acid (AA) activates the assembly of NADPH oxidase to generate superoxide anion. There is a gap in the current literature regarding which PLA(2) isoform regulates NADPH oxidase activation. The aim of this study was to identify the PLA(2) isoform involved in the regulation of superoxide generation in neutrophils and investigate if PLA(2) Mediates priming in response to pathologic hyperglycemia. Neutrophils were isolated from people with diabetes mellitus and healthy controls, and HL60 neutrophil-like cells were grown in hyperglycemic conditions. Incubating neutrophils with the Ca2+-independent PLA(2) (iPLA(2)) inhibitor bromoenol lactone (BEL) completely suppressed fMLP-induced generation of superoxide. The nonspecific actions of BEL on phosphatidic acid phosphohydrolase-1, p47(phox) phosphorylation, and apoptosis were ruled out by specific assays. Small interfering RNA knockdown of iPLA(2) inhibited superoxide generation by neutrophils. Neutrophils from people with poorly controlled diabetes and in vitro incubation of neutrophils with high glucose and the receptor for advanced glycation end products ligand S100B greatly enhanced superoxide generation compared with controls, and this was significantly inhibited by BEL. A modified iPLA(2) assay, Western blotting, and PCR confirmed that there was increased iPLA(2) activity and expression in neutrophils from people with diabetes. AA (10 mu M) partly rescued the inhibition of superoxide generation mediated by BEL, confirming that NADPH oxidase activity is, in part, regulated by AA. This study provides evidence for the role of iPLA(2) in enhanced superoxide generation in neutrophils from people with diabetes mellitus and presents an alternate pathway independent of protein kinase C and phosphatidic acid phosphohydrolase-1 hydrolase signaling. The Journal of Immunology, 2010, 184: 1507-1515.

DOI： 10.4049/jimmunol.0901219

Resolvin E1 Receptor Activation Signals Phosphorylation and Phagocytosis Reviewed

Taisuke Ohira, Makoto Arita, Kazuhiro Omori, Antonio Recchiuti, Thomas E. Van Dyke, Charles N. Serhan

JOURNAL OF BIOLOGICAL CHEMISTRY 285 ( 5 ) 3451 - 3461 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Resolvins are endogenous lipid mediators that actively regulate the resolution of acute inflammation. Resolvin E1 (RvE1; (5S, 12R, 18R)-trihydroxy-6Z, 8E, 10E, 14Z, 16E-eicosapentaenoic acid) is an endogenous anti-inflammatory and pro-resolving mediator derived from eicosapentaenoic acid that regulates leukocyte migration and enhances macrophage phagocytosis of apoptotic neutrophils to resolve inflammation. In the inflammatory milieu, RvE1 mediates counter-regulatory actions initiated via specific G protein-coupled receptors. Here, we have identified RvE1-specific signaling pathways initiated by the RvE1 receptor ChemR23. RvE1 stimulated phosphorylation of Akt that was both ligand-and receptor-dependent. RvE1 regulated Akt phosphorylation in a time (0-15 min)- and dose-dependent (0.01-100 nM) manner in human ChemR23-transfected Chinese hamster ovary cells. RvE1 stimulated phosphorylation of both Akt and a 30-kDa protein, a downstream target of Akt, identified using a phospho-Akt substrate antibody. The 30-kDa protein was identified as ribosomal protein S6, a translational regulator, and its phosphorylation was inhibited by a phosphatidylinositol 3-kinase (PI3K) inhibitor (wortmannin) and an ERK inhibitor (PD98059) but not by a p38-MAPK inhibitor (SB203580). Ribosomal protein S6 is a downstream target of the PI3K/Akt signaling pathway as well as the Raf/ERK pathway. In ChemR23-expressing differentiated HL60 cells, RvE1 also stimulated the phosphorylation of ribosomal protein S6. In addition, RvE1 enhanced phagocytosis of zymosanAby human macrophages, which are inhibited by PD98059 and rapamycin (mTOR inhibitor). These results indicate that RvE1 initiates direct activation of ChemR23 and signals receptor-dependent phosphorylation. These phosphorylation-signaling pathways identified for RvE1 receptor-ligand interactions underscore the importance of endogenous pro-resolving agonists in resolving acute inflammation.

DOI： 10.1074/jbc.M109.044131

PDK1 Regulates Chemotaxis in Human Neutrophils Reviewed

M. Yagi, A. Kantarci, T. Iwata, K. Omori, S. Ayilavarapu, K. Ito, H. Hasturk, T. E. Van Dyke

JOURNAL OF DENTAL RESEARCH 88 ( 12 ) 1119 - 1124 2009.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS INC

Phosphoinositide-dependent kinase (PDK1) plays a central role in signal transduction mediated by phosphatidylinositol 3-kinases (PI3K) and regulates cellular functions in neutrophils. Neutrophils from individuals diagnosed with localized aggressive periodontitis (LAP) present an in vivo phenotype with depressed chemotaxis. The aim of this study was to test the hypothesis that PDK1 regulates chemotaxis in neutrophils and is responsible for the abnormal neutrophil chemotaxis LAP. Neutrophil chemotaxis was significantly suppressed by the PDK1 inhibitor staurosporine. When cells were transfected with PDK1 siRNA, there was a significant reduction in chemotaxis, while superoxide generation was not significantly affected. In primary neutrophils from persons with LAP, PDK1 expression and activation levels were significantly reduced, and this reduction was associated with the reduced phosphorylation of Akt (Thr308) and chemotaxis. Analysis of these data demonstrates that PDK1 is essential for the chemotactic migration of neutrophils, and in the absence of PDK1, neutrophil chemotaxis is impaired.

DOI： 10.1177/0022034509349402

　 PREV - NEXT 　

1
2
3