Cytotoxicity of intracanal dressings on apical papilla cells differ upon activation with E. faecalis LTA

Abstract Objective The aim of this study was to investigate the cytotoxic effects of modified triple antibiotic paste and an experimental composition using calcium hydroxide on lipoteichoic acid (LTA)-primed apical papilla cells (APC). Material and Methods Human APC were tested for in vitro cytotoxicity of modified Triple Antibiotic Paste (mTAP - Ciprofloxacin, Metronidazole and Cefaclor at 1:1:1) and of a paste of Ciprofloxacin, Metronidazole and Calcium hydroxide (CMC - 1:1:2) and modified CMC (mCMC - 2:2:1) by using MTT assay. The substances were reconstituted in DMEM at 1,000 µg/mL and » serially diluted before being kept in contact with cells for 1, 3, 5 and 7 days. Further, cells were primed with 1 µg/mL of Enterococcus faecalis LTA for 7 days prior to the viability test with 1,000 µg/mL of each substance. Statistical analysis was performed using one-way analysis of variance (ANOVA) and two-way ANOVA respectively followed by Tukey's post-test. Significance levels were set at p<0.05. Results In the first assay, the higher cytotoxic rates were reached by mTAP for all experimental periods. CMC was found toxic for APC at 5 and 7 days, whereas mCMC did not affect the cell viability. Only CMC and mCMC were able to induce some cellular proliferation. In the second assay, when considering the condition with medium only, LTA-primed cells significantly proliferated in comparison to LTA-untreated ones. At this context, mTAP and CMC showed similar cytotoxicity than the observed for LTA-untreated cells, while mCMC was shown cytotoxic at 7 days only for LTA-primed APC. Comparing the medications, mTAP was more cytotoxic than CMC and mCMC. Conclusion mTAP showed higher cytotoxicity than CMC and mCMC and the effect of topic antimicrobials might differ when tested against apical papilla cells under physiological or activated conditions.

Anti-neuro-inflammatory effects of Nardostachys chinensis in lipopolysaccharide-and lipoteichoic acid-stimulated microglial cells / 中国天然药物

Excessive microglial cell activation is related to the progression of chronic neuro-inflammatory disorders. Heme oxygenase-1 (HO-1) expression mediated by the NFE2-related factor (Nrf-2) pathway is a key regulator of neuro-inflammation. Nardostachys chinensis is used as an anti-malarial, anti-nociceptive, and neurotrophic treatment in traditional Asian medicines. In the present study, we examined the effects of an ethyl acetate extract of N. chinensis (EN) on the anti-neuro-inflammatory effects mediated by HO-1 up-regulation in Salmonella lipopolysaccharide (LPS)- or Staphylococcus aureus lipoteichoic acid (LTA)-stimulated BV2 microglial cells. Our results indicated that EN suppressed pro-inflammatory cytokine production and induced HO-1 transcription and translation through Nrf-2/antioxidant response element (ARE) signaling. EN markedly inhibited LPS- and LTA-induced activation of nuclear factor-kappa B (NF-κB) as well as phosphorylation of mitogen-activated protein kinases (MAPKs) and signal transducer and activator of transcription (STAT). Furthermore, EN protected hippocampal HT22 cells from indirect neuronal toxicity mediated by LPS- and LTA-treated microglial cells. These results suggested that EN impairs LPS- and LTA-induced neuro-inflammatory responses in microglial cells and confers protection against indirect neuronal damage to HT22 cells. In conclusion, our findings indicate that EN could be used as a natural anti-neuro-inflammatory and neuroprotective agent.

Human soluble dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin inhibits phagocytosis of Staphylococcus aureus by immature dendritic cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect and mechanism of soluble dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (sDC-SIGN) on the phagocytosis of Staphylococcus aureus (S. aureus) by immature dendritic cells (imDCs).</p><p><b>METHODS</b>Flow cytometry was employed to examine the effect of sDC-SIGN on the phagocytosis of S. aureus by imDCs. Enzyme-linked immunosorbent assay (ELISA) was used to analyze the binging of sDC-SIGN to S. aureus, lipoteichoic acid (LTA) and lipopolysaccharides (LPS) and investigate the effect of the ligands mannan and LTA and anti-DC-SIGN antibodies 1C6 and 4H3 on the binging of sDC-SIGN to S. aureus.</p><p><b>RESULTS</b>sDC-SIGN inhibited the phagocytosis of S. aureus by imDCs. sDC-SIGN bound to S. aureus in a Ca(2+)-dependent manner. sDC-SIGN concentration-dependently bound to LTA, but not to LTA, and the binging of sDC-SIGN to S. aureus was blocked by mannan, LTA, 1C6 and 4H3.</p><p><b>CONCLUSION</b>sDC-SIGN preferentially binds to the carbohydrate constituents on S. aureus to affect the binding between membrane-bound DC-SIGN and S. aureus, thus suppressing the phagocytosis of S. aureus by imDCs.</p>

Binding Specificity of Philyra pisum Lectin to Pathogen-Associated Molecular Patterns, and Its Secondary Structure

We recently reported a Philyra pisum lectin (PPL) that exerts mitogenic effects on human lymphocytes, and its molecular characterization. The present study provides a more detailed characterization of PPL based on the results from a monosaccharide analysis indicating that PPL is a glycoprotein, and circular dichroism spectra revealing its estimated alpha-helix, beta-sheet, beta-turn, and random coil contents to be 14.0%, 39.6%, 15.8%, and 30.6%, respectively. These contents are quite similar to those of deglycosylated PPL, indicating that glycans do not affect its intact structure. The binding properties to different pathogen-associated molecular patterns were investigated with hemagglutination inhibition assays using lipoteichoic acid from Gram-positive bacteria, lipopolysaccharide from Gram-negative bacteria, and both mannan and beta-1,3-glucan from fungi. PPL binds to lipoteichoic acids and mannan, but not to lipopolysaccharides or beta-1,3-glucan. PPL exerted no significant antiproliferative effects against human breast or bladder cancer cells. These results indicate that PPL is a glycoprotein with a lipoteichoic acid or mannan-binding specificity and which contains low and high proportions of alpha-helix and beta-structures, respectively. These properties are inherent to the innate immune system of P. pisum and indicate that PPL could be involved in signal transmission into Gram-positive bacteria or fungi.

Study on the expression of Toll like receptor 2 and interleukin-1 beta induced by Enterococcus faecalis lipoteichoic acid on human periodontal ligament cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression of Toll like receptor 2 (TLR2) and interleukin-1 beta (IL-1 beta) of cultured human periodontal ligament cells (HPDLCs) activated by Enterococcus faecalis (E. faecalis) lipoteichoic acid (LTA).</p><p><b>METHODS</b>HPDLCs that were obtained from the periodontal tissues of healthy humans were maintained in proper condition. Flow cytometry was used to detect the expression of TLR2 on normal HPDLCs and infectious HPDLCs which were incubated with 0.1, 1, 10 microg mL(-1) E. faecalis LTA for 24 h. IL-1 beta was detected by enzyme linked immunosorbent assay (ELISA) after incubating with LTA of the above concentration for 12, 24 and 48 h or pretreated with TLR2 neutralizing antibody for 1 h and then co-cultured with 1 microg mL(-1) LTA for 24 h.</p><p><b>RESULTS</b>E. faecalis LTA promoted the expression of TLR2 in normal HPDLCs. The difference had statistical significance (P<0.05). IL-1 beta secretion could be detected 12h after stimulation with LTA and increasingly escalate within 48h (P<0.05). TLR2 neutralizing antibody had no evident effect on IL-1 beta generation stimulating by E. faecalis LTA.</p><p><b>CONCLUSION</b>E. faecalis LTA can increase the expression of TLR2 and IL-1 beta in normal HPDLCs.</p>

Effects of Peroxisome Proliferator-Activated Receptor-gamma on the Production of Tumor Necrosis Factor-alpha in Stimulated Human Monocoytes / 감염과화학요법

BACKGROUND: We evaluated the effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) on the production of tumor necrosis factor-alpha (TNF-alpha) and expression of nuclear factor-kappaB (NF-kappaB) in stimulated THP-1 cells, a human monocyte cell line. MATERIALS AND METHODS: We evaluated the cytotoxic effect of 15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), one of natural PPAR-gamma ligands, using commercial cell proliferation assay. Cells were pretreated with 15d-PGJ(2) and then stimulated with lipopolysaccharide (LPS) or lipoteichoic acid (LTA). The amount of TNF-alpha was measured by using commercial ELISA method. NF-kappaB activation was evaluated by Western blot analysis. RESULTS: 15d-PGJ(2) showed dose-dependent cytotoxic effect on the tested cells after 4 hr of treatment. Stimulation of cells by LPS or LTA induced TNF-alpha production. TNF-alpha production was markedly decreased in the cells pretreated with 15d-PGJ(2) compared to cells treated only with LPS or LTA in a dose-dependent manner. Pretreatment of 15d-PGJ(2) reduced LPS or LTA induced NF-kappaB expression in the nuclear extracts of THP-1 cells. CONCLUSION: 15d-PGJ(2) pretreatment decreased TNF-alpha production from the THP-1 cells stimulated by LPS or LTA, and this assumed to be associated with inhibition of NF-kappaB activation.

Expression of Toll-like Receptor 2 in Cultured Human Keratinocytes: The Effect of Bacterial Antigens, Cytokines and Calcium Concentration

BACKGROUND: Toll-like receptors (TLRs) are expressed by human epidermal keratinocytes and are involved in immune responses. OBJECTIVE: The goal of this was to investigate the expression of TLR2 in response to bacterial antigens, cytokines, and different calcium concentrations. METHODS: The expression of TLR2 was assessed after stimulation by lipoteichoic acid (LTA) and streptolysin O (SLO). In addition, TLR2 expression was evaluated after treatment with IFN-gamma and TNF-alpha, and different concentrations of calcium. The expression levels of TLR2 mRNA and protein were studied using RT-PCR and Western blot analysis. RESULTS: Cultured human epidermal keratinocytes constitutively expressed TLR2 and the expression was stimulated by LTA and SLO; in addition, IFN-gamma and TNF-alpha upregulated TLR2 expression. However, the changes in TLR2 expression associated with the calcium concentrations were insignificant. CONCLUSION: TLR2 expression increased with the concentration and duration of bacterial pathogens and this increase was amplified by several cytokines, from activated keratinocytes and other cells.

Toll-like Receptors 2 and 4 and Their Mutations in Patients with Otitis Media and Middle Ear Effusion

OBJECTIVES: Toll-like receptors (TLRs) detect microbial infections and they can directly induce innate host defense responses. TLR 2 has been shown to be primarily involved in the recognition of peptidoglycans and lipoteichoic acid of gram positive bacteria. TLR 4 recognizes lipopolysaccharides and lipoteichoic acids from both gram-negative and gram-positive bacteria. Both mutations lead a reduced capacity to elicit inflammation and they increase the risk for gram-positive and negative infections. This study was performed to investigate the expressions of TLR 2 and 4 and their mutations in patients suffering with otitis media and middle ear effusion. METHODS: Middle ear fluid samples were collected from 40 otitis media effusion (OME) patients who had ventilating tubesinserted. Bacteria in the effusion fluid were detected by standard bacterial culture. The secreted IgG, IgA and IgM were measured by Enzyme-linked immunosorbent assay. TLR 2 and 4 were assessed by performing RT-PCR. The genomic DNA from each patient was isolated from the middle ear fluid samples that were collected from 60 OME patients, and the presence of mutations was determined by performing restriction digestion and DNA sequencing analysis. RESULTS: Among the 40 middle ear fluid samples, bacteria were detected in 13 middle ear fluid samples. The amounts of IgM, IgA, and IgG were 151.20+/-60.94 ng/mL, 21.59+/-7.96 ng/mL and 11.55+/-16.98 ng/mL, respectively. TLR 2 and 4 were expressed in the middle ear fluid and the expression of TLR 2 was higher than that of TLR 4. However, there was no correlation between the expressions of TLR 2 and 4, and the concentration of immunoglobulin or the presence of bacteria (P>0.05). There ware no mutations of TLR 2 (Arg753Gln, Arg677Trp) and TLR 4 (Asp299Gly, Thr399Ile). CONCLUSION: TLR 2 and 4 were expressed in all the middle ear fluid samples of OME, but the mutations of TLR 2 and 4 were not detected. TLR 2 and 4 may play a vital role in the immunological responses of patients with OME.

Production of interleukin-1beta, interleukin-6 and tumor necrosis factor a in cultured human fibroblast with stimulation of abstract from Actinomyces naeslundii ATCC19246 / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the production of interleukin (IL)-1beta, IL-6 and tumor necrosis factor alpha (TNFalpha) from stimulated human fibroblast with abstract from cell wall of Actinomyces naeslundii ATCC19246.</p><p><b>METHODS</b>The abstract from the cell wall from Actinomyces naeslundii were extracted and purified with the method of purifying lipoteichoic acid(LTA) and stimulated the THP-1 with three different concentrations (1, 10, 100 mg/mL). The level of IL-1beta, IL-6 and TNFalpha in the supernatant was quantitatively analyzed by ELISA. Results Abstracts at the concentrations of 10, 100 mg/mL significantly produced IL-1beta, IL-6 and TNFalpha, especially 10 mg/mL.</p><p><b>CONCLUSION</b>The abstract from cell wall of Actinomyces naeslundii may significantly increase IL-1beta, IL-6 and TNFalpha level in the supernatant of THP-1, and the increasing level is different with the concentrations.</p>

Effect of lipoteichoic acid of Bifidobacterium on survivin and its regulatory genes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The aim of this study is designed to explore the anti-tumor effect of lipoteichoic acid (LTA) of Bifidobacterium on the expression of survivin in colon cancer LoVo cells and its possible regulatory mechanism.</p><p><b>METHODS</b>The changes of survivin mRNA and protein in LoVo cells treated with LTA of Bifidobacterium were detected by RT-PCR and Western blot. Meanwhile, the expressions of pAKT (the key protein kinase in P13K/AKT signal transduction pathway), p53 and PTEN were measured by Western blot.</p><p><b>RESULTS</b>There were overexpressions of survivin mRNA and protein in LoVo cells. After treated with different dose of LTA of Bifidobacterium, the expressions of survivin mRNA and protein were markedly decreased in a dose-dependent manner (P < 0.01). Besides, the activity of pAKT was decreased significantly (P < 0.01) and the expression of p53 and PTEN was increased (P < 0.01).</p><p><b>CONCLUSION</b>LTA of Bifidobacterium can down-regulate the expression of survivin in LoVo cells through inhibiting the activity of PI3K/AKT signal transduction pathway and up-regulate the expression of p53. Accordingly, the activity of caspases is increased, and apoptosis of LoVo cells occurs ultimately.</p>

Endogenous nitric oxide mediates lipoteichoic acid induced preconditioning on reoxygenation injury of cultured human coronary artery endothelial cells / 药学学报

<p><b>AIM</b>To explore the effects of lipoteichoic acid (LTA) induced delayed preconditioning (PC) on hypoxia-reoxygenation (H/R) injury of cultured human coronary artery endothelial cells (HCAECs), and to investigate the potential role of endogenous nitric oxide (NO) participated in the protective mechanism.</p><p><b>METHODS</b>HCAECs were incubated for 2 h in a hypoxic atmosphere and reoxygenated for 4 h in a normoxic atmosphere. The delayed PC was induced by pretreatment with LTA (30 or 300 microg x L(-1)) for 4 h before 24 h recovery. The extent of cellular injury after reoxygenation was assessed by the percentage of cellular injury with Trypan blue exclusion and by the amount of lactate dehydrogenase (LDH) in culture media. The NO level of the culture media was measured spectrophotometrically. Furthermore, HCAECs were exposed to 300 microg x L(-1) of LTA for 4 h, and to detect the expression of eNOS mRNA by RT-PCR method after cells were recovered from different points.</p><p><b>RESULTS</b>LTA pretreatment significantly decreased the percentage of the killed cell and the concentration of LDH in media. Also, LTA pretreatment obviously raised the concentrations of NO in culture media. The protective effects of LTA were abrogated by pretreatment with N-monomethyl-L-arginine (L-NMMA). Moreover, the expression of eNOS mRNA was significantly upregulated after HCAECs exposure to LTA for 4 h following 2 h or 4 h recovery.</p><p><b>CONCLUSION</b>LTA could induce the delayed protection against H/R induced endothelial injury and dysfunction of cultured HCAECs. NO produced by eNOS acts initially as a trigger and subsequently as a mediator of delayed PC.</p>

The reaction of dental pulp to Escherichia coli lipopolysaccharide and Enterococcus faecalis lipoteichoic acid

This research evaluates the effects of the lipopolysaccharides (LPS) from Escherichia coli and lipoteichoic acid (LTA) from Enterococcus faecalis on dental pulp. These molecules are components of the Gram-negative and Gram-positive bacteria cell wall, respectively. Ten dogs were used in the experiment. Inoculation in surgically opened pulp and coronal restoration with glass ionomer was the method chosen. The evaluation times were 1, 7, 15, 30 and 60 days. The results showed that the LPS and LTA, at 150 icg/ml, produced a negative interference in the pulp leading to destruction. LTA caused less damage than LPS.

Tissue reactions to a component of root canal system bacteria: lipoteichoic acid

Lipoteichoic acid (LTA), present in Gram-positive microorganisms, has physiochemical characteristics that allow it to act as an immunogen. Due to polymicrobial characteristics of root canal infections, LTA can participate in the development of periapical disease. The reaction of the rat subcutaneous tissue to Teflon tube implants, filled with Fibrinol soaked in lipoteichoic acid (concentration of 150 æg/ml), was observed. Lipoteichoic acid provoked an inflammatory tissue reaction

Effects of lipoteichoic acid induced delayed preconditioning on ischemia-reperfusion injury in isolated rat hearts / 华中科技大学学报（医学）（英德文版）

To explore the potential of lipoteichoic acid (LTA) induced cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts and whether endogenous nitric oxide (NO) participates in the protection, the rats were pretreated with LTA (1 mg/kg, i.p.) 24 h before the experiment, and the isolated hearts were subjected to 30 min no-flow normothermic global ischemia and 60 min reperfusion after a 20-min stabilization period by the langendorff method. Cardiac functions were evaluated at the end of stabilization, and at 30 min, 60 min of reperfusion. The amounts of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase(LDH) and total NO oxidation products in the coronary effluent were measured spectrophotometrically at the end of reperfusion. It was revealed that pretreatment with LTA could significantly improve the recovery of cardiac function, reduce the release of CK-MB and LDH, and increase the concentrations of NO in coronary effluent. The protective effects were abrogated by pretreatment of the rats with L-NAME. It was concluded that LTA could induce the delayed cardioprotection against I/R injury, and endogenous NO may be involved in the mechanisms.

Influence of bacterial factors on proliferation of bovine mammary epithelial cells

Effects of bovine mastitis pathogen virulence factors on mammary epithelial cell function are not clearly understood. In this study, the effect of streptococcal lipoteichoic acid (LTA), streptokinase, and Escherichia coli lipopolysaccharide (LPS) on proliferation of a primary bovine mammary epithelial cell culture (BTE) and on an established bovine mammary epithelial cell line (MAC-T) was evaluated. Mammary epithelial cells were cultured in the presence of bacterial virulence factors for 48 h at 37 degrees C. BTE cell proliferation was inhibited by streptococcal LTA at 8 and 16 micrograms/ml whereas MAC-T cell proliferation was reduced significantly by concentrations of LTA > or = 2 micrograms/ml. Streptokinase had no effect on proliferation of either MAC-T or BTE cells and LPS inhibited proliferation of BTE but not of MAC-T cells. Effect of LTA and LPS on mammary epithelial cell proliferation could be relevant during the periparturient period when mammary glands are markedly susceptible to new intramammary infection and when mammary epithelial cells undergo extensive proliferation, differentiation and synthesis of milk components.

Spectrophotometric study of the relative affinities of teichoic acid for different metal ions.

Spectrophotometric study of the relative affinities of teichoic acid (TA) for Na+, Ca2+, Mg2+, Cd2+, Hg2+, Cu2+ and Pb2+ described on the basis of the disruption of metachromasia of dye 1,9-dimethyl methylene blue (DMMB)-polyanion (TA) system has revealed the following sequence of relative affinities of TA for these metals: Na+ < Ca2+ < or = Mg2+ < Cd2+ < Hg2+ < Cu2+ < Pb2+. Some of the metal ions particularly Pb2+ and Hg2+ have specific interactions with the dye, and induce distinct metachromatic band of the dye even in the absence of the polyanion.

Determination of teichoic acid antibody for the diagnosis of pediatric staphylococcal infections.

Determination of teichoic acid antibodies by Enzyme-linked Immunosorbent Assay (ELISA) was done in 39 patients with Staphylococcus aureus infections and 151 patients who did not have a history of serious staphylococcal infections. The latter who were treated for other diseases served as controls. Various levels of teichoic acid antibodies below 1:3,200 were detected in controls while significantly higher levels were seen in patients with Staphylococcus aureus infections.

Antiribitol-teichoic acid antibody (ARTA) in diagnosis of deep seated Staphylococcus aureus infections.

Antiribitol-teichoic acid antibody (ARTA) was detected in sera of 30 out of 50 patients (60%) with various acute deep seated Staphylococcus aureus infections and 5 out of 10 chronic osteomyelitis cases, whereas none of the sera from 50 patients with superficial Staphylococcus aureus infections as well from 50 patients without Staphylococcus aureus infections showed antibody response (p less than 0.01). This test is a definite advantage in diagnosis of deep seated staphylococcal infections like endocarditis, lung disease, meningitis and specially in osteomyelitis cases where organisms cannot be isolated and therefore helps in predicting the need for long term antimicrobial therapy.

Induction of metachromasia and circular dichroism in the dye 1,9-dimethyl methylene blue by S. aureus wall teichoic acid.

Teichoic acid (TA) isolated from the Gram-positive bacteria Staphylococcus aureus induces blue shifted metachromasia in the dye 1,9-dimethyl methyleneblue (DMMB). Results of conductometric titrations show that DMMB binds to TA with 1:1 stoichiometry. Unlike DNA, this TA does not induce a definite metachromatic band in the dye acridine orange. S. aureus TA also induces strong circular dichroism (CD) in this dye with molar ellipticity value of the order of 10(4). This induction of CD in DMMB supports our earlier inference that TA in dilute solution at neutral pH has a helical conformation, and is not a random coil polymer.

Spectrophotometric and spectrofluorometric titrations of teichoic acid.

Spectrophotometric and spectrofluorometric titrations of two strongly aggregating dyes, 1,9-dimethylmethylene blue (DMMB) and acridine orange (AO), by three anionic biopolymers, chondroitin sulphate A, DNA and teichoic acid (TA), have been described. Though the three polymers differ in their dye binding efficiencies and TA is a weak chromotrope, the equivalent weights of the polymers can be estimated accurately by these methods using the two dyes. Results show DMMB to be the preferred dye for spectrophotometric titration. The titrations can be used to estimate the equivalent weights of anionic polymers, and also for the quantitative estimation of such polymers of known equivalent weights.