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Oral bacteria signal transduction

B A Herbert, C M Novince, K L Kirkwood
Aggregatibacter actinomycetemcomitans is a perio-pathogenic bacteria that has long been associated with localized aggressive periodontitis. The mechanisms of its pathogenicity have been studied in humans and preclinical experimental models. Although different serotypes of A. actinomycetemcomitans have differential virulence factor expression, A. actinomycetemcomitans cytolethal distending toxin (CDT), leukotoxin, and lipopolysaccharide (LPS) have been most extensively studied in the context of modulating the host immune response...
June 2016: Molecular Oral Microbiology
Elaine M Haase, Xianghui Feng, Jiachuan Pan, Jeffrey C Miecznikowski, Frank A Scannapieco
Streptococcus gordonii, a primary colonizer of the tooth surface, interacts with salivary α-amylase via amylase-binding protein A (AbpA). This enzyme hydrolyzes starch to glucose, maltose, and maltodextrins that can be utilized by various oral bacteria for nutrition. Microarray studies demonstrated that AbpA modulates gene expression in response to amylase, suggesting that the amylase-streptococcal interaction may function in ways other than nutrition. The goal of this study was to explore the role of AbpA in gene regulation through comparative transcriptional profiling of wild-type KS1 and AbpA(-) mutant KS1ΩabpA under various environmental conditions...
August 15, 2015: Applied and Environmental Microbiology
Silvia Stockinger, Claudia U Duerr, Marcus Fulde, Tamas Dolowschiak, Johanna Pott, Ines Yang, Daniel Eibach, Fredrik Bäckhed, Shizuo Akira, Sebastian Suerbaum, Martijn Brugman, Mathias W Hornef
Recent results indicate a significant contribution of innate immune signaling to maintain mucosal homeostasis, but the precise underlying signal transduction pathways are ill-defined. By comparative analysis of intestinal epithelial cells isolated from conventionally raised and germ-free mice, as well as animals deficient in the adaptor molecules MyD88 and TRIF, the TLR3 and TLR4, as well as the type I and III IFN receptors, we demonstrate significant TLR-mediated signaling under homeostatic conditions. Surprisingly, homeostatic expression of Reg3γ and Paneth cell enteric antimicrobial peptides critically relied on TRIF and, in part, TLR3 but was independent of IFN receptor signaling...
October 15, 2014: Journal of Immunology: Official Journal of the American Association of Immunologists
Dipanwita Sengupta, Dae-Joong Kang, Cecilia Anaya-Bergman, Tiana Wyant, Arnab K Ghosh, Hiroshi Miyazaki, Janina P Lewis
Prevotella intermedia is an oral bacterium implicated in a variety of oral diseases. Although internalization of this bacterium by nonphagocytic host cells is well established, the molecular players mediating the process are not well known. Here, the properties of a leucine-rich repeat (LRR) domain protein, designated AdpF, are described. This protein contains a leucine-rich region composed of 663 amino acid residues, and molecular modeling shows that it folds into a classical curved solenoid structure. The cell surface localization of recombinant AdpF (rAdpF) was confirmed by electron and confocal microscopy analyses...
June 2014: Infection and Immunity
Matthew L Williams, Paula J Crowley, Adnan Hasona, L Jeannine Brady
Streptococcus mutans is a cariogenic oral pathogen whose virulence is determined largely by its membrane composition. The signal recognition particle (SRP) protein-targeting pathway plays a pivotal role in membrane biogenesis. S. mutans SRP pathway mutants demonstrate growth defects, cannot contend with environmental stress, and exhibit multiple changes in membrane composition. This study sought to define a role for ylxM, which in S. mutans and numerous other bacteria resides directly upstream of the ffh gene, encoding a major functional element of the bacterial SRP...
June 2014: Journal of Bacteriology
Nicholas S Jakubovics, Sufian A Yassin, Alexander H Rickard
It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease...
2014: Advances in Applied Microbiology
Teresa Schaumann, Dominik Kraus, Jochen Winter, Michael Wolf, James Deschner, Andreas Jäger
Gingival epithelial cells (GECs) represent a physical barrier against bacteria and are involved in the processes of innate immunity. Recently, an anti-inflammatory and immune-modulatory effect of the amino acid glycine has been demonstrated. However, there is only little information about the immune-modulatory effects of glycine in oral tissues. This study aimed to investigate the existence and role of the glycine receptor in gingival tissue analyzing tissues/cells from extracted human molars via immunohistochemical analysis...
2013: Clinical & Developmental Immunology
Sun Woong Hong, Jung Eun Baik, Seok-Seong Kang, Cheol-Heui Yun, Deog-Gyu Seo, Seung Hyun Han
Streptococcus mutans is a pathogenic Gram-positive bacterium that is closely associated with dental caries and subsequent pulpal inflammation. Although lipoteichoic acid (LTA) is considered a major virulence factor of Gram-positive bacteria, little is known about the innate immunity to S. mutans LTA. In this study, we purified LTA from S. mutans (Sm.LTA) through n-butanol extraction, hydrophobic interaction column chromatography, and ion-exchange column chromatography to investigate its immunological properties using murine macrophages...
February 2014: Molecular Immunology
Qian Li, Chunling Pan, Di Teng, Li Lin, Yurong Kou, Elaine M Haase, Frank A Scannapieco, Yaping Pan
Pseudomonas aeruginosa is an important opportunistic bacterial pathogen, causing infections of respiratory and other organ systems in immunocompromised hosts that may invade and proliferate in mucosal epithelial cells to induce apoptosis. Previous studies suggest that oral bacteria, especially gram-negative periodontal pathogens, may enhance P. aeruginosa invasion into respiratory epithelial cells to augment tissue destruction. In this study, we investigated the effect of the periodontopathogen Porphyromonas gingivalis on P...
January 2014: Microbes and Infection
Srinivas R Myneni, Rajendra P Settem, Ashu Sharma
Bone undergoes a continuous cycle of remodeling for maintenance and healing. For almost a decade it has been appreciated that the immune system is intricately linked to bone homeostasis. Both acute and chronic inflammatory responses have been shown to impact bone health. A common form of inflammatory disease that causes bone destruction is the chronic infectious disease known as periodontitis (PD). PD is a bacteria-driven inflammation of the tooth-supporting apparatus that leads to resorption of the alveolar (jaw) bone, often leading to tooth loss...
2013: Immunological Investigations
Dominique S Michaud
Established risk factors for pancreatic cancer, including tobacco smoking, chronic pancreatitis, obesity and type 2 diabetes, collectively account for less than half of all pancreatic cancer cases. Inflammation plays a key role in pancreatic carcinogenesis, but it is unclear what causes local inflammation, other than pancreatitis. Epidemiological data suggest that Helicobacter pylori may be a risk factor for pancreatic cancer, and more recently, data suggest that periodontal disease, and Porphyromonas gingivalis, a pathogen for periodontal disease, may also play a role in pancreatic carcinogenesis...
October 2013: Carcinogenesis
Yizu Jiao, Youssef Darzi, Kazuki Tawaratsumida, Julie T Marchesan, Mizuho Hasegawa, Henry Moon, Grace Y Chen, Gabriel Núñez, William V Giannobile, Jeroen Raes, Naohiro Inohara
Periodontitis is a common disease that is characterized by resorption of the alveolar bone and mediated by commensal bacteria that trigger host immune responses and bone destruction through unidentified mechanisms. We report that Nod1, an innate intracellular host receptor for bacterial peptidoglycan-related molecules, is critical for commensal-induced periodontitis in a mouse model. Mice lacking Nod1 exhibit reduced bone resorption as well as impaired recruitment of neutrophils to gingival tissues and osteoclasts to the alveolar bone, which mediate tissue and bone destruction...
May 15, 2013: Cell Host & Microbe
Mike Curtis
The mechanisms through which commensal bacterial populations cause inflammatory disease when shifted to dysbiotic community structures are poorly understood. Jiao et al. (2013) demonstrate that, in the case of inflammatory disease in the mouth, stimulation of the intracellular pattern recognition receptor Nod1 is a critical determinant.
May 15, 2013: Cell Host & Microbe
Pei-Pei Lin, You-Miin Hsieh, Wei-Wen Kuo, Yueh-Min Lin, Yu-Lan Yeh, Chien-Chung Lin, Fuu-Jen Tsai, Chang-Hai Tsai, Cheng-Chih Tsai, Chih-Yang Huang
Inflammation plays an important role in triggering fibrosis of cardiovascular disease and hypertension. Gamma-aminobutyric acid (GABA) has hypotensive effect; GABA concentration could be enhanced in milk fermented with lactic acid bacteria (LAB). This study evaluated the effect of probiotic-fermented purple sweet potato yogurt (PSPY) on the toll-like receptor 4 (TLR-4)-related inflammatory components, and on fibrosis in the heart of spontaneously hypertensive rat (SHR). TLR4-related pathway and fibrosis-associated proteins TGFbeta and FGF2 were significantly increased in SHR hearts, but were highly suppressed in 10% PSPY-fed rats...
June 30, 2013: Chinese Journal of Physiology
Delphine Dufour, Céline M Lévesque
Streptococci are among the predominant bacterial species living in the human body. They are normally harmless bacteria, but have the ability to cause diverse infections, ranging from mild (e.g., tooth decay and sore throat) to life-threatening (e.g., endocarditis and meningitis). Streptococci have evolved various means of coping with the deleterious effects of environmental stressors and avoiding the host immune system. Recently, several studies have shown that streptococci colonizing the mouth and upper respiratory tract are able to mount complex stress responses in order to persist and successfully survive competition in their ecological niche...
May 2013: Future Microbiology
V di Giacomo, S Pacella, M Rapino, M Di Giulio, S Zara, G Pasquantonio, L Cellini, A Cataldi
AIM: To investigate in coculture of human gingival fibroblasts (HGFs) and Streptococcus mitis, the molecular mechanisms driving the response to 2-hydroxyethyl methacrylate (HEMA) in terms of eukaryotic/prokaryotic cell adhesion, signal transduction and apoptosis. METHODOLOGY: The clinical strain S. mitis DS12, cultured in Trypticase soy broth was added to HGFs, obtained from fragments of healthy marginal gingival tissue and cultured in DMEM, treated with 3 mmol L(-1) 2-hydroxyethyl methacrylate (HEMA) for 48 h and processed for microscopic, western blotting and flow cytometric analyses...
December 2013: International Endodontic Journal
Camille Zenobia, Xiao Long Luo, Ahmed Hashim, Toshiharu Abe, Lijian Jin, Yucheng Chang, Zhi Chao Jin, Jian Xun Sun, George Hajishengallis, Mike A Curtis, Richard P Darveau
The oral and intestinal host tissues both carry a heavy microbial burden. Although commensal bacteria contribute to healthy intestinal tissue structure and function, their contribution to oral health is poorly understood. A crucial component of periodontal health is the recruitment of neutrophils to periodontal tissue. To elucidate this process, gingival tissues of specific-pathogen-free and germ-free wild-type mice and CXCR2KO and MyD88KO mice were examined for quantitative analysis of neutrophils and CXCR2 chemoattractants (CXCL1, CXCL2)...
August 2013: Cellular Microbiology
Octavio A Gonzalez, M John Novak, Sreenatha Kirakodu, Arnold J Stromberg, Shu Shen, Luis Orraca, Janis Gonzalez-Martinez, Jeffrey L Ebersole
Apoptotic processes are important for physiologic renewal of an intact epithelial barrier and contribute some antimicrobial resistance for bacteria and viruses, as well as anti-inflammatory effects that benefits the mucosa. The oral cavity presents a model of host-bacterial interactions at mucosal surfaces, in which a panoply of microorganisms colonizes various niches in the oral cavity and creates complex multispecies biofilms that challenge the gingival tissues. This report details gene expression in apoptotic pathways that occur in oral mucosal tissues across the lifespan, using a nonhuman primate model...
March 2013: Apoptosis: An International Journal on Programmed Cell Death
Mukta Deobagkar-Lele, Suni K Chacko, Emmanuel S Victor, Jayachandra C Kadthur, Dipankar Nandi
Thymic atrophy is known to occur during infections; however, there is limited understanding of its causes and of the cross-talk between different pathways. This study investigates mechanisms involved in thymic atrophy during a model of oral infection by Salmonella enterica serovar Typhimurium (S. typhimurium). Significant death of CD4(+) CD8(+) thymocytes, but not of single-positive thymocytes or peripheral lymphocytes, is observed at later stages during infection with live, but not heat-killed, bacteria. The death of CD4(+) CD8(+) thymocytes is Fas-independent as shown by infection studies with lpr mice...
April 2013: Immunology
A Menendez, B P Willing, M Montero, M Wlodarska, C C So, G Bhinder, B A Vallance, B B Finlay
Paneth cell α-defensins are antimicrobial peptides involved in the control of the intestinal microbiota and immunological homeostasis. In mice, they are encoded by multiple, highly homologous genes (Defa). The transcriptional activity of ileal Defa genes was studied in response to pharmacological and genetic perturbations of the intestinal environment of C57BL/6 mice. Defa gene transcription was sensitive to oral antibiotic administration suggesting that commensal microbes regulate Defa expression. Ileal microbiota analysis showed that decreased transcription of Defa genes correlated with depletion of Lactobacillus...
2013: Journal of Innate Immunity
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