iTRAQ-based quantitative analysis reveals the mechanism underlying the changes in physiological activity in a glutamate racemase mutant strain of Streptococcus mutans UA159.

Streptococcus mutans UA159 is responsible for human dental caries with robust cariogenic potential. Our previous study noted that a glutamate racemase (MurI) mutant strain (designated S. mutans FW1718), with the hereditary background of UA159, displayed alterations of morphogenesis, attenuated stress tolerance, and weakened biofilm-forming capabilities, accompanying with unclear mechanisms. In this study, we applied isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics to characterize the proteome profiles of the murI mutant strain vs. the wild-type strain in chemically defined media to elucidate the mechanisms by which S. mutans copes with MurI deficiency. Whole-cell proteins of S. mutans FW1718 and UA159 were assessed by iTRAQ-coupled LC-ESI-MS/MS. Furthermore, differentially expressed proteins (DEPs) were identified by Mascot, Gene Ontology (GO) annotation, Cluster of Orthologous Groups of proteins (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Finally, a protein-protein interaction (PPI) network was established using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). Among 1173 total bacterial proteins identified, 112 DEPs exhibited altered expression patterns in S. mutans UA159 with or without the murI mutation. The ΔmurI cells displayed an increase in the relative expression of 93 proteins (fold change ≥ 1.2, p < 0.05) and a decrease in 29 proteins (fold change ≤ 0.833, p < 0.05) compared with the wild-type cells. PPI analysis revealed a complex network of DEPs containing 191 edges and 122 nodes. The DEPs significantly upregulated after murI knockout had roles in diverse functional processes spanning cell-wall biosynthesis, energy production, and DNA replication and repair. We identified distinct variations and diverse modulators caused by murI mutation in the proteome of S. mutans, indicating that the modification of cell membrane structure, redistribution of energy metabolism and enhanced nucleic acid machinery contributed to the S. mutans response to specific environmental contexts.

Comparison of mineral trioxide aggregate and calcium hydroxide for apexification of immature permanent teeth: A systematic review and meta-analysis.

BACKGROUND/PURPOSE: Calcium hydroxide and mineral trioxide aggregate (MTA) are used for inducing a calcific barrier at an open tooth root (apexification). The purpose of this study was to compare the efficacy of calcium hydroxide and MTA for apexification of immature permanent teeth. METHODS: Medline, Cochrane, EMBASE, and Google Scholar were searched until November 24, 2015, using the keywords apexification, permanent teeth, MTA, and calcium hydroxide. RESULTS: Of 216 studies identified, four studies were included. There were no differences in the clinical success rate [pooled odds ratio (OR) = 3.03, 95% confidence interval (CI): 0.42-21.72, p = 0.271], radiographic success rate (pooled OR = 4.30, 95% CI: 0.45-41.36, p = 0.206), or apical barrier formation rate (pooled OR = 1.71, 95% CI: 0.59-4.96, p = 0.322) between calcium hydroxide and MTA groups. The time required for apical barrier formation was significantly less in the MTA group (pooled difference in means = -3.58, 95% CI: from -4.91 to -2.25, p < 0.001). CONCLUSION: While both materials provide similar success rates, the shorter treatment time with MTA may translate into higher overall success rates because of better patient compliance.

[Preparation of Shuxiong pulsatile controlled-release dropping pill].

OBJECTIVE: To prepare Shuxiong pulsatile controlled-release dropping pill and study the influencing factors in vitro. METHODS: Dropping pills with suitable size (10 - 15 mg) were coated with swelling layer containing croscarmellose sodium and controlled-release layer containing ethylcellulos aqueous dispersion respectively to prepare Shuxiong pulsatile controlled-release dropping pill. The effects of the materials of swelling layer, the weight of swelling layer and controlled-release layer on the release of drugs were investigated to optimize the process technology and validate formula. RESULTS: The release behavior was influenced strikingly by the types and weight of coating layer. The optimal formula was as follows: Shuxiong pulsatile controlled-release dropping pills were prepared using croscarmellose sodium as inner layer with 15% (weight) coating level and ethylcellulose aqueous dispersion (Surelease) as outer controlled-release layer with 7% (weight) coating level. The lag time of prepared pulsatile controlled-release dropping pills was about 4 h and accumulative release rate reached 80% within 4 h. CONCLUSION: The drug release of Shuxiong pulsatile controlled-release dropping pill is shown in pulsatile way in vitro.

Yin-chen Wu-ling powder alleviate cholestatic liver disease: Network pharmacological analysis and experimental validation.

BACKGROUND: Yin-chen Wu-ling Powder (YWP) has potential therapeutic effects on cholestatic liver disease (CLD), however, its active compounds and conceivable mechanism are as yet indistinct. METHODS: The network pharmacology and gene function annotation examined the multiple active ingredients, potential targets, and possible mechanisms of YWP in CLD treatment. Then the molecular docking reassured the reliability of the core compounds including the key genes and farnesoid X receptor (FXR). Finally, The Mdr2-/- mice were used to test the effect and mechanism of YWP against CLD. RESULTS: The network analysis identified nine main active ingredients, including quercetin, capillarisin, eupalitin, isorhamnetin, skrofulein, genkwanin, cerevisterol, gederagenin, and sitosterol. The PPI network predicted the ten hub genes involved were AKT1, MAPK1, MAPK14, IL6, RXRA, ESR1, IL10, NCOA1, CAV1, and EGFR. The KEGG and GO analysis showed that YWP might contribute to CLD treatment through the PI3K/Akt and MAKP signalings to manage pathological reactions, for instance, inflammatory responses. The molecular docking displayed a functional similarity among the core compounds with ursodeoxycholic acid (UDCA) and Obeticholic acid (OCA) on the effects on AKT1, MAPK1, MAPK14, RXRA, and ESR, and the affinity to FXR. In addition, the YWP could significantly attenuate hepatic injury and improve inflammatory response in Mdr2-/- mice. The mechanism exploration showed that YWP mainly decreased inflammatory response by inhibiting AKT/P38MAPK signaling. CONCLUSION: This study firstly revealed the multiple active ingredients, potential targets, and possible mechanism of YWP to treat CLD based on network pharmacology Analysis and molecular docking. YWP could alleviate cholestasis in Mdr2-/- mice by impairing inflammation via inhibiting AKT/P38MAPK Signaling.

A nuclear ligand MRG15 involved in the proapoptotic activity of medicinal fungal galectin AAL (Agrocybe aegerita lectin).

BACKGROUND: We have previously reported a novel fungal galectin Agrocybe aegerita lectin (AAL) with apoptosis-induced activity and nuclear migration activity. The importance of nuclear localization for AAL's apoptosis-induced activity has been established by mutant study. However, the mechanism remains unclear. METHODS: We further investigated the mechanism using a previously reported carbohydrate recognition domain (CRD) mutant protein H59Q, which retained its nuclear localization activity but lost most of its apoptotic activity. The cell membrane-binding ability of recombinant AAL (rAAL) and H59Q was analyzed by FACS, and their cellular partners were identified by affinity chromatography and mass spectroscopy. Furthermore, the interaction of AAL and ligand was proved by mammalian two-hybrid and pull down assays. A knockdown assay was used to confirm the role of the ligand. RESULTS: The apoptotic activity of AAL could be blocked by lactose. Mutant H59Q retained comparable cell membrane-binding ability to rAAL. Four cellular binding partners of AAL in HeLa cells were identified: glucose-regulated protein 78 (GRP78); mortality factor 4-like protein 1 (MRG15); elongation factor 2 (EEF2); and heat shock protein 70 (Hsp70). CRD region of AAL was required for the interaction between AAL/mutant AAL and MRG15. MRG15 knockdown increased the cells' resistance to AAL treatment. CONCLUSION: MRG15 was a nuclear ligand for AAL in HeLa cells. These data implied the existence of a novel nuclear pathway for the antitumor activity of fungal galectin AAL. GENERAL SIGNIFICANCE: These findings provide a novel explanation of AAL bioactivity and contribute to the understanding of mushroom lectins' antitumor activity.

Importance of nuclear localization for the apoptosis-induced activity of a fungal galectin AAL (Agrocybe aegerita lectin).

Agrocybe aegerita lectin (AAL) was identified previously in our group as a novel galectin from medicinal fungi Agrocybe aegerita, and has been shown to effectively induce cancer cell cycle arrest and apoptosis in vitro and tumor regression in vivo. Here, AAL was observed to translocate into the HeLa cell nucleus and induce cell apoptosis when it was predominantly in the nucleus. The N-terminus and C-terminus of AAL were required for nuclear localization. Site mutated proteins were generated based on AAL structure. Dimer interface mutant I25G, carbohydrate recognition domain (CRD) mutant R63H, and loop region mutant L33A could not enter the nucleus and lost the ability to induce apoptosis. CRD mutant H59Q and loop region mutant I144G maintained nuclear localization activity, and H59Q retained residual bioability but I144G had no activity, indicating that nuclear localization is important but not sufficient for AAL to become apoptotically active. Our findings provide a novel antitumor mechanism of fungal galectin.

KDM3A and KDM4C Regulate Mesenchymal Stromal Cell Senescence and Bone Aging via Condensin-mediated Heterochromatin Reorganization.

Epigenomic changes and stem cell deterioration are two hallmarks of aging. Accumulating evidence suggest that senescence of mesenchymal stromal cells (MSCs) perpetuates aging or age-related diseases. Here we report that two H3K9 demethylases, KDM3A and KDM4C, regulate heterochromatin reorganization via transcriptionally activating condensin components NCAPD2 and NCAPG2 during MSC senescence. Suppression of KDM3A or KDM4C by either genetic or biochemical approach leads to robust DNA damage response and aggravates cellular senescence, whereas overexpression of KDM3A/KDM4C or NCAPD2 promotes heterochromatin reorganization and blunts DNA damage response. Moreover, MSCs derived from Kdm3a-/- mice exhibit defective chromosome organization and exacerbated DNA damage response, which are associated with accelerated bone aging. Consistently, analysis of human bone marrow MSCs and transcriptome database reveals inverse correlation of KDM3A/KDM4C and/or NCAPD2/NCAPG2 with aging. Taken together, the present finding unveils that H3K9 demethylases function as a surveillance mechanism to restrain DNA damage accumulation in stem cells during aging.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens.

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs.

Etiology and Prevention of Gastric Cancer.

BACKGROUND: Gastric cancer is a heterogeneous malignant disease associated with environmental and genetic predisposing factors. While gastric cancer incidence and mortality fell greatly globally over the past decades, it remains the fourth cause of cancer-related death worldwide. Thus, prevention of gastric cancer is still a major strategy for improvement of gastric cancer prognosis. SUMMARY: Helicobacter pylori infection has been demonstrated to be a major risk factor for the development of gastric cancer. Unhealthy diet and lifestyle, including high-salt food, smoking and drinking, are able to induce genotypic and phenotypic transformation of gastric epithelial cells. Gene mutations (such as E-cadherin) in stomach epithelial cells are major genetic causes for gastric cancer. The eradication of H. pylori has been demonstrated to be an effective approach for primary prevention of gastric cancer. Increased intake of a diet rich in vegetables and fresh fruits as well as smoking cessation have been shown to reduce the incidence of gastric cancer. The secondary prevention strategy is to screen premalignant gastric lesions by endoscopy. Biomarker tests are also reliable methods to identify gastric precancerous lesions. Endoscopy screening is still the gold standard for diagnosis of gastric cancer. KEY MESSAGE: H. pylori infection, a diet rich in salted and/or smoked food and red meat, as well as gene mutations are major risk factors for the development of gastric cancer. PRACTICAL IMPLICATIONS: The eradication of H. pylori is a major primary preventive strategy of gastric cancer. A healthy lifestyle, including increased intake of a diet rich in fruit and vegetables, reduced intake of salted and smoked food and red meat, a reduction of alcohol intake as well as smoking cessation will be effective approaches for the prevention of gastric cancer.

Survivin inhibitor YM155 suppresses gastric cancer xenograft growth in mice without affecting normal tissues.

Survivin overexpression is associated with poor prognosis of human gastric cancer, and is a target for gastric cancer therapy. YM155 is originally identified as a specific inhibitor of survivin. In this study, we investigated the antitumor effect of YM155 on human gastric cancer. Our results showed that YM155 treatment significantly inhibited cell proliferation, reduced colony formation and induced apoptosis of gastric cancer cells in a dose-dependent manner. Accordingly, YM155 treatment significantly decreased survivin expression without affecting XIAP expression and increased the cleavage of apoptosis-associated proteins caspase 3, 7, 8, 9. YM155 significantly inhibited sphere formation of gastric cancer cells, suppressed expansion and growth of the formed spheres (cancer stem cell-like cells, CSCs) and downregulated the protein levels of ß-catenin, c-Myc, Cyclin D1 and CD44 in gastric cancer cells. YM155 infusion at 5 mg/kg/day for 7 days markedly inhibited growth of gastric cancer xenograft in a nude mouse model. Immunohistochemistry staining and Western Blot showed that YM155 treatment inhibited expression of survivin and CD44, induced apoptosis and reduced CD44+ CSCs in xenograft tumor tissues in vivo. No obvious pathological changes were observed in organs (e.g. heart, liver, lung and kidney) in YM155-treated mice. Our results demonstrated that YM155 inhibits cell proliferation, induces cell apoptosis, reduces cancer stem cell expansion, and inhibits xenograft tumor growth in gastric cancer cells. Our results elucidate a new mechanism by which YM155 inhibits gastric cancer growth by inhibition of CSCs. YM155 may be a promising agent for gastric cancer treatment.

Additive effects of C(2)-ceramide on paclitaxel-induced premature senescence of human lung cancer cells.

AIMS: the aims of the study are to investigate the additive effect of exogenous short-carbon chain phospholipids, C(2)-ceramide, on an anti-cancer drug paclitaxel (PTX)-induced senescence of human non-small cell lung cancer (NSCLC) cells deficient in functional p53 and p16, and to examine whether mitogen-activated protein kinase (MAPK) plays a role in ceramide-sensitized senescence of NSCLC cells. MAIN METHODS: to determine whether exogenous C(2)-ceramide renders lung cancer cells more sensitive to PTX treatment, techniques employing a flow cytometry-based cell cycle analysis and acidic ß-galactosidase staining for senescent cells were used. Furthermore, to elucidate the role of MAPK proteins in modulating senescence, assays for protein levels of selective MAPKs and Bcl-2 family members, and detection of transcriptional levels senescence-associated genes were used in the study. KEY FINDINGS: a sub-lethal dose of C(2)-ceramide sensitized the NSCLC H1299 cells to PTX treatment. The additive effects of C(2)-ceramide and PTX resulted in proliferative inhibition, G(2)-phase arrest of cell cycle, activation of p38 and eventually premature senescence. Importantly, neither p53, p21(waf1/cip1) nor p16(ink4) was shown to be involved in C(2)-ceramide-sensitized proliferative inhibition and senescence of H1299 cells by PTX in our study. SIGNIFICANCE: our study demonstrates that the short-carbon chain C(2)-ceramide can effectively sensitize PTX-induced senescence of H1299 cells via both p21(waf1/cip1)- and p16(ink4)-independent pathways.

[Clinical effect of pit and fissure sealant used in combination with self-etching adhesive on permanent teeth].

PURPOSE: To determine the role of pit and fissure sealant used in combination with self-etching adhesive in retention of the sealants and caries decrease of the permanent teeth. METHODS: Sixty two children aged 6-14 years old were chosen from the outpatients in the Department of Pediatric Dentistry, the first or the second permanent molars (n= 156) were sealed with two kinds of sealant. The tooth in one side was sealed with sealant (Concise, 3M-ESPE) and self-etching system (Adper and Prompt, 3M-ESPE) while the tooth in the other side was sealed with sealant (Concise, 3M-ESPE) and phosphate acid system. All the patients were followed up and reexamined 3, 6 and 12 months after treatment. Statistical analysis was carried out with SPSS 12.0 (SPSS Inc., Chicago, IL, USA) software package for Chi-square test and t test. RESULTS: The operating time using self-etching system was (122 +/- 13)s, shorter than (219 +/- 13)s using phosphate acid system (P < 0.05). The self-etching system used only one step to finish etching, adhesion and treatment of tooth surface, saving the steps of rinsing and drying. The retention rates of pit and fissure sealant in self-etching system and phosphate acid system were 97.4% and 96.2% respectively at the third month, 94.9% and 92.3% at the sixth month, 91.0% and 88.4% at the end of one year after treatment. The prevalence rate of caries in both groups had no significant difference (P>0.05); No caries in both groups were found in the first three months; In patients using self-etching system, caries decreased by 100% at the sixth month and by 50% at the end of one year. CONCLUSION: Adper Prompt self-etching adhesive, with an advantage of simple operation and shorter operation period, is effective in bonding sealant to the enamel. The retention rates of pit and fissure sealant were not different between the two groups.

[MGB probes detect Streptococcus mutans and Streptococcus sobrinus in real time].

OBJECTIVE: To detect and distinguish Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) quickly in epidemiology and investigate the distribution of S. mutans in the oral of children with rampant caries. METHODS: Designed minor groove binder (MGB) probes according to the gtf gene of S. mutans and S. sobrinus. Detected 9 reference strains of Streptococcus mutans group by MGB probes in real time and after cultivation. Evaluated the results of these two methods. 92 dental plaques from pre-school children with rampant caries were detected in real time with MGB probes. RESULTS: The primers could amplify the target sequences specificity and distinguished S. mutans and S. sobrinus from each other using MGB probes. Though the fluorescence occurred earlier in S. mutans than in S. sobrinus, they had the same results in nature. In 92 children with rampant caries, the detective ratio of S. mutans was 96.7% and that of S. sobrinus was 32.6%. All the samples which could detect S. sobrinus were positive for S. mutans. CONCLUSION: The primers and probe designed from gtf genes of S. mutans and S. sobrinus can amplify the target sequence and distinguish them from each other in real time.