Xylitol and erythritol inhibit real-time biofilm formation of Streptococcus mutans

Background: Regular consumption of xylitol decreases the number of cariogenic streptococci in dental plaque. In vitro biofilm models to study the mechanism of xylitol action have been set-up, but the obtained results are contradictory. Biofilm growth is a dynamic process with time-specific characteristics that may remain undetected in conventional end-point biofilm tests. In this study we used an impedance spectroscopy instrument, xCELLigence Real Time Cell Analyzer (RTCA), that allows label-free, non-invasive real-time monitoring of biofilm formation, to explore effects of xylitol on biofilm formation by Streptococcus mutans. Based on the obtained information of biofilm dynamics, we assessed the number of viable bacteria, the polysaccharide content, and the expression levels of selected genes involved in glucan-mediated biofilm formation in different biofilm stages. Xylitol inhibition was compared with that of erythritol; another polyol suggested to have a positive impact on oral health.Results: Our results showed that real-time monitoring provided new information of polyol-induced changes in S. mutans biofilm formation dynamics. The inhibitory effect of polyols was more pronounced in the early stages of biofilm formation but affected also the measured total amount of formed biofilm. Effects seen in the real-time biofilm assay were only partially explained by changes in CFU values and polysaccharide amounts in the biofilms. Both xylitol and erythritol inhibited real-time biofilm formation by all the nine tested S. mutans strains. Sensitivity of the strains to inhibition varied: some were more sensitive to xylitol and some to erythritol. Xylitol also modified the expression levels of gbpB, gtfB, gtfC and gtfD genes that are important in polysaccharide-mediated adherence of S. mutans.Conclusion: The erythritol- and xylitol- induced inhibition of biofilm formation was only partly explained by decrease in the number of viable S. mutans cells or the amount of polysaccharides in the biofilm matrix, suggesting that in addition to reduced proliferation also the matrix composition and thereby the surface attachment quality of biofilm matrix may be altered by the polyols.</div

Structures of SALSA/DMBT1 SRCR domains reveal the conserved ligand-binding mechanism of the ancient SRCR fold

The scavenger receptor cysteine-rich (SRCR) family of proteins comprises more than 20 membrane-associated and secreted molecules. Characterised by the presence of one or more copies of the similar to 110 amino-acid SRCR domain, this class of proteins have widespread functions as antimicrobial molecules, scavenger receptors, and signalling receptors. Despite the high level of structural conservation of SRCR domains, no unifying mechanism for ligand interaction has been described. The SRCR protein SALSA, also known as DMBT1/gp340, is a key player in mucosal immunology. Based on detailed structural data of SALSA SRCR domains 1 and 8, we here reveal a novel universal ligand-binding mechanism for SALSA ligands. The binding interface incorporates a dual cation-binding site, which is highly conserved across the SRCR superfamily. Along with the well-described cation dependency on most SRCR domain-ligand interactions, our data suggest that the binding mechanism described for the SALSA SRCR domains is applicable to all SRCR domains. We thus propose to have identified in SALSA a conserved functional mechanism for the SRCR class of proteins

Hinokitiol Dysregulates Metabolism of Carcinoma Cell Lines and Induces Downregulation of HPV16E6 and E7 Oncogenes and p21 Upregulation in HPV Positive Cell Lines

Background: Hinokitiol (beta-thujaplicin), isolated from the wood of Chamaecyparis taiwanensis, has a wide variety of biological properties including anti-inflammatory, anti-microbial, and anti-tumor effects. Therefore, hinokitiol has become a frequent additive in oral and other healthcare products. Objectives: Our goal was to determine the anti-tumor activity of hinokitiol on human papillomavirus (HPV) positive (n = 3) and negative (n = 2) cell lines derived from cervical or head and neck squamous cell carcinoma (HNSCC) and keratinocyte cell lines (n = 3) transformed spontaneously or with HPV16E6 and E7 oncogenes. Methods: The cell-lines were exposed to hinokitiol at different concentrations (0-200 mu M) for 24 h. Cell metabolism, proliferation, and the cell cycle distribution were assessed by MTT- and H-3-thymidine incorporation and flow cytometry. Expressions of p21 and on HPV16E6 and E7 oncogenes were assessed by qPCR. Results: In all carcinoma cell lines, hinokitiol treatment declined the metabolic activity irrespective of the HPV status. This decline was statistically significant, however, only in HPV-positive cell lines CaSki and UD-SCC-2 when exposed to hinokitiol concentrations at 100 and 200 mu M, respectively (p Conclusions: Our results indicate that hinokitiol might have potential in preventing the progress of immortalized cells toward malignancy and the growth of malignant lesions. Hinokitiol can also influence on the progression of HPV-associated lesions by downregulating the E6 and E7 expression.</p

Salivary IgA and IgG Antibody Responses against Periodontitis-Associated Bacteria in Crohn’s Disease

Elevated serum immunoglobulin (Ig) antibody levels are observed in Crohn’s disease patients. The aim of this study was to evaluate the salivary IgA and IgG antibody levels against Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia in Crohn’s disease patients. Eighty-eight participants (47 Crohn’s disease patients and 41 systemically healthy age- and gender-matched controls) were included in the study. Oral and medical health statuses were recorded and salivary samples were collected. Salivary P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia carriage were analyzed with DNA sequencing technique, salivary levels of IgG1, IgG2, IgG3, IgG4, and IgM were measured with the Luminex® xMAP™ technique, and salivary IgA and IgG antibody levels against P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia were detected by ELISA. As result, higher salivary IgG2 (p = 0.011) and IgG3 (p = 0.006), P. gingivalis IgA (p < 0.001), A. actinomycetemcomitans IgG (p = 0.001), and P. intermedia IgG (p < 0.001) antibody levels were detected in the Crohn’s disease group compared to the controls. Salivary P. gingivalis carriage was lower in the Crohn’s disease group in comparison to the controls (p = 0.024). In conclusion, salivary IgA antibody responses against P. gingivalis and IgG antibody responses against P. intermedia have independent associations with Crohn’s disease

Hinokitiol Dysregulates Metabolism of Carcinoma Cell Lines and Induces Downregulation of HPV16E6 and E7 Oncogenes and p21 Upregulation in HPV Positive Cell Lines

Background: Hinokitiol (β‐thujaplicin), isolated from the wood of Chamaecyparis taiwanensis, has a wide variety of biological properties including anti‐inflammatory, anti‐microbial, and anti‐tumor effects. Therefore, hinokitiol has become a frequent additive in oral and other healthcare products. Objectives: Our goal was to determine the anti‐tumor activity of hinokitiol on human papillomavirus (HPV) positive (n = 3) and negative (n = 2) cell lines derived from cervical or head and neck squamous cell carcinoma (HNSCC) and keratinocyte cell lines (n = 3) transformed spon-taneously or with HPV16E6 and E7 oncogenes. Methods: The cell‐lines were exposed to hinokitiol at different concentrations (0–200μM) for 24 h. Cell metabolism, proliferation, and the cell cycle distribution were assessed by MTT‐ and3H‐thymidine incorporation and flow cytometry. Expres-sions of p21 and on HPV16E6 and E7 oncogenes were assessed by qPCR. Results: In all carcinoma cell lines, hinokitiol treatment declined the metabolic activity irrespective of the HPV status. This decline was statistically significant, however, only in HPV‐positive cell lines CaSki and UD‐SCC‐2 when exposed to hinokitiol concentrations at 100 and 200 μM, respectively (p < 0.05). Immortalized cell lines, HMK and HPV‐positive IHGK, were more sensitive as a similar metabolic effect was achieved at lower hinokitiol concentrations of 3.1, 6.25, and 50 μM, respectively. Hinokitiol blocked DNA synthesis of all carcinoma cell lines without evident association with HPV status. G1 cell cycle arrest and p21 upregulation was found in all cell lines after hinokitiol treatment at higher concen-tration. However, when the p21 results of all HPV‐positive cells were pooled together, the increase in p21 expression was statistically significantly higher in HPV‐positive than in HPV‐negative cell lines (p = 0.03), but only at the highest hinokitiol concentration (200 μM). In HPV‐positive cell lines hinokitiol declined the expression of HPV16E7 and E6 along the increase of p21 expression. The dose‐dependent inverse correlation between p21 and E7 was statistically significant in SiHa cells (r = −0.975, p‐value = 0.03) and borderline in UD‐SCC‐2 cells (r = −0.944, p‐value = 0.06), in which p21 and E6 were also inversely correlated (r = −0.989). Conclusions: Our results indicate that hinokitiol might have potential in preventing the progress of immortalized cells toward malignancy and the growth of malignant lesions. Hinokitiol can also influence on the progression of HPV‐associated lesions by downregulating the E6 and E7 expression.publishedVersionPeer reviewe

Longitudinal Dynamics of HPV16 Antibodies in Saliva and Serum among Pregnant Women

publishedVersionPeer reviewe

Low rate of asymptomatic carriage and salivary immunoglobulin A response to Group A Streptococci in the healthy adult population in Finland

Streptococcus pyogenes, also called group A streptococcus (GAS), is a human pathogen causing a wide range of infections ranging from mild tonsillitis to severe, life threatening conditions such as bacteraemia, necrotizing fasciitis, and streptococcal toxic shock syndrome. GAS may also colonise the oropharynx without causing any signs of disease which is known as asymptomatic carriage. This study aims to investigate IgA responses against GAS and oral streptococci from saliva samples collected from healthy Finnish adults. In addition, asymptomatic throat GAS carriage was studied. The study participants consisted of healthy adult volunteers who provided one saliva sample, a throat swab, and a background questionnaire. Total salivary IgA, and GAS specific IgA were analysed from the saliva samples using enzyme-linked immunosorbent assays (ELISA) and the results were compared to oral streptococci specific IgA levels. Asymptomatic GAS throat carriers were identified by bacterial culture, and the isolates were emm typed. Samples from a total of 182 individuals were analysed. The median salivary IgA concentration was 62.9 mu g/ml (range 17.3-649.9 mu g/ml), and median GAS and oral streptococcal specific IgA concentrations 2.7 and 3.3 arbitrary units (AU, range 1.4-7.4 AU and 1.6-12.0 AU), respectively. Three individuals with asymptomatic GAS throat carriage were identified

Regulation of gingival keratinocyte monocyte chemoattractant protein-1-induced protein (MCPIP)-1 and mucosa-associated lymphoid tissue lymphoma translocation protein (MALT)-1 expressions by periodontal bacteria, lipopolysaccharide, and interleukin-1β

BackgroundThe aim of this study was to evaluate oral bacteria- and interleukin (IL)-1β-induced protein and mRNA expression profiles of monocyte chemoattractant protein-1-induced protein (MCPIP)-1 and mucosa-associated lymphoid tissue lymphoma translocation protein (MALT)-1 in human gingival keratinocyte monolayers and organotypic oral mucosal models.MethodsHuman gingival keratinocyte (HMK) monolayers were incubated with Porphyromonas gingivalis, Fusobacterium nucleatum, P. gingivalis lipopolysaccharide (LPS) and IL-1β. The protein levels of MCPIP-1 and MALT-1 were examined by immunoblots and mRNA levels by qPCR. MCPIP-1 and MALT-1 protein expression levels were also analyzed immunohistochemically using an organotypic oral mucosal model. One-way analysis of variance followed by Tukey correction was used in statistical analyses.ResultsIn keratinocyte monolayers, MCPIP-1 protein expression was suppressed by F. nucleatum and MALT-1 protein expression was suppressed by F. nucleatum, P. gingivalis LPS and IL-1β. P. gingivalis seemed to degrade MCPIP-1 and MALT-1 at all tested time points and degradation was inhibited when P. gingivalis was heat-killed. MCPIP-1 mRNA levels were increased by P. gingivalis, F. nucleatum, and IL-1β, however, no changes were observed in MALT-1 mRNA levels.ConclusionGingival keratinocyte MCPIP-1 and MALT-1 mRNA and protein expression responses are regulated by infection and inflammatory mediators. These findings suggest that periodontitis-associated bacteria-induced modifications in MCPIP-1 and MALT-1 responses can be a part of periodontal disease pathogenesis.</p

Edible films based on milk proteins release effectively active immunoglobulins

Objectives: The goal of this study was to develop novel compositions of edible protein coatings based on immunoglobulin (Ig) fraction from bovine milk. Protein coatings can be used to protect foods against microbial, chemical, and physical damage. We developed novel compositions of edible protein coatings based on immunoglobulin (Ig) fraction from bovine milk. A lot of Ig could be obtained from under-utilized side streams of dairy industry. To the best of our knowledge, such use of the Ig fraction has not been published earlier.Materials and Methods: Bovine colostral Ig's were incorporated in edible films based on various milk proteins and investigated the characteristics of the films including solubility of Ig's and nisin and on technological properties of films. Ig's specific to cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus were produced to colostrums by hyperimmunizing cows before parturition.Results: The milk Ig rich fraction suited well as a component of milk protein films. The Ig's dissolved from the films very rapidly. Nisin, commoly used for food protection, was used as a model of antimicrobial peptide. Nisin was released biologically active from both beta-lactoglobulin (beta-lg) and beta-lg/Ig films. Nisin exerted its bactericidal effect at clearly lower concentrations in the beta-lg/Ig films when compared with beta-lg film. Nisin also retained its activity better in film containing Ig-enriched whey. Incorporating Ig-enriched whey into films enhanced adhesion and tensile strength of the films. The Ig-enriched whey also affected strongly on the appearance of films based on commercial whey protein concentrate in a dose-dependent way by making the films more smooth, transparent, and clear which are all favoured properties in most food and pharmaceutical applications.Conclusions: Biologically active Ig's can be successfully incorporated in and released from milk protein based edible films. The content of Igs in films affected considerably technological properties of these films. Composition of other proteins in films had effect on preservability and release of Igs.</div

Bacterial adhesion of Streptococcus suis to host cells and its inhibition by carbohydrate ligands

Peer reviewe