Bacterial modulins: a novel class of virulence factors which cause host tissue pathology by inducing cytokine synthesis

Relationship of MMP-9 with the clinical course of apical periodontitis and the main bacterial species in the oral microbiota

Bacterial products, host immune cells and cytokines have been reported to play an important role in the pathogenesis of apical periodontitis (AP). This study aimed to determine the main bacterial species in the microbiota as gram positive and negative and to compare the relationship between matrix metalloproteinase (MMP)-9 and tumor necrosis factor (TNF)-α with controlled patient groups. 60 patients with AP and extraction indication were included in the study. 30 systemically healthy volunteers without AP were selected as the control group. After access cavity preparation, an initial microbiologic sample (S1) was taken from the root canal. After atraumatic extraction of the tooth, a second microbial sample (S2) was taken from the extraradicular region. After bacterial DNA extraction, 16S rRNA gene primer was designed for sequence analysis. Bacterial community profiling was made by Sanger sequencing of the PCR products. In addition, serum MMP-9 and TNF-α levels were measured from all patients. TNF-α levels of the AP group were higher than the control group, while MMP-9 levels were found to be lower (p = 0.0264 and p = 0.0146, respectively). There was no difference in the main bacterial species isolated from the samples taken from the intracanal and extraradicular region of the tooth with AP (p = 0.714). The main bacterial species in the intracanal region of the tooth with AP are similar to the main bacterial species in the extraradicular region. The pathophysiology of the tooth with AP is associated with low MMP-9 and high TNF-α, independent of the bacterial species in the intracanal and extraradicular regions.

The root canal microbiome diversity and function. A whole-metagenome shotgun analysis

AIM

To evaluate the root canal microbiome composition and bacterial functional capability in cases of primary and secondary apical periodontitis utilizing whole-metagenome shotgun sequencing.

METHODOLOGY

Twenty-two samples from patients with primary root canal infections, and 18 samples obtained from previously treated teeth currently diagnosed with apical periodontitis were analysed with whole-metagenome shotgun sequencing at a depth of 20 M reads. Taxonomic and functional gene annotations were made using MetaPhlAn3 and HUMAnN3 software. The Shannon and Chao1 indices were utilized to measure alpha diversity. Differences in community composition were evaluated utilizing analysis of similarity (ANOSIM) using Bray-Curtis dissimilarities. The Wilcoxon rank sum test was used to compare differences in taxa and functional genes.

RESULTS

Microbial community variations within a community were significantly lower in secondary relative to primary infections (alpha diversity p = .001). Community composition was significantly different in primary versus secondary infection (R = .11, p = .005). The predominant taxa observed among samples (>2.5%) were Pseudopropionibacterium propionicum, Prevotella oris, Eubacterium infirmum, Tannerella forsythia, Atopobium rimae, Peptostreptococcus stomatis, Bacteroidetes bacterium oral taxon 272, Parvimonas micra, Olsenella profusa, Streptococcus anginosus, Lactobacillus rhamnosus, Porphyromonas endodontalis, Pseudoramibacter alactolyticus, Fusobacterium nucleatum, Eubacterium brachy and Solobacterium moorei. The Wilcoxon rank test revealed no significant differences in relative abundances of functional genes in both groups. Genes with greater relative abundances (top 25) were associated with genetic, signalling and cellular processes including the iron and peptide/nickel transport system. Numerous genes encoding toxins were identified: exfoliative toxin, haemolysins, thiol-activated cytolysin, phospholipase C, cAMP factor, sialidase, and hyaluronic glucosaminidase.

CONCLUSIONS

Despite taxonomic differences between primary and secondary apical periodontitis, the functional capability of the microbiomes was similar.

Sterilization of Human Amniotic Membrane Using an Ozone Hydrodynamic System

Human amniotic membrane (hAM) is an important biomaterial for Tissue Engineering, due to its great regenerative properties and potential use as a scaffold. The most used procedure to sterilize biomaterials is gamma-irradiation, but this method can affect several properties, causing damage to the structure and reducing the growth factors. The present work evaluated the efficiency of a new method based on ozonated dynamic water for hAM sterilization. HAM fragments were experimentally contaminated with Staphylococcus aureus, Escherichia coli, Candida albicans, Staphylococcus epidermidis, and Clostridium sporogenes (106 CFU/mL) and submitted to sterilization process for 5, 10 and 15 min. The analyses did not reveal microbial activity after 10 min for S. aureus and C. sporogenes and after 15 min for E. coli and S. epidermidis. The microbial activity of C. albicans was reduced with the exposure time increase, but the evaluated time was insufficient for complete sterilization. The depyrogenation process was investigated for different ozonation times (15, 20, 25, 30, and 35 min) to evaluate the ozone sterilization potential and presented promising results after 35 min. The ozone effect on hAM structure was evaluated by histological analysis. A decrease in epithelium average thickness was observed with the exposure time increase. Furthermore, some damage in the epithelium was observed when hAM was exposed for 10 and 15 min. It can indicate that ozone, besides being effective in sterilization, could promote the hAM sample's de-epithelization, becoming a possible new method for removing the epithelial layer to use hAM as a scaffold.

Construction of an aerolysin-based multi-epitope vaccine against Aeromonas hydrophila: an in silico machine learning and artificial intelligence-supported approach

Aeromonas hydrophila, a gram-negative coccobacillus bacterium, can cause various infections in humans, including septic arthritis, diarrhea (traveler's diarrhea), gastroenteritis, skin and wound infections, meningitis, fulminating septicemia, enterocolitis, peritonitis, and endocarditis. It frequently occurs in aquatic environments and readily contacts humans, leading to high infection rates. This bacterium has exhibited resistance to numerous commercial antibiotics, and no vaccine has yet been developed. Aiming to combat the alarmingly high infection rate, this study utilizes in silico techniques to design a multi-epitope vaccine (MEV) candidate against this bacterium based on its aerolysin toxin, which is the most toxic and highly conserved virulence factor among the Aeromonas species. After retrieval, aerolysin was processed for B-cell and T-cell epitope mapping. Once filtered for toxicity, antigenicity, allergenicity, and solubility, the chosen epitopes were combined with an adjuvant and specific linkers to create a vaccine construct. These linkers and the adjuvant enhance the MEV's ability to elicit robust immune responses. Analyses of the predicted and improved vaccine structure revealed that 75.5%, 19.8%, and 1.3% of its amino acids occupy the most favored, additional allowed, and generously allowed regions, respectively, while its ERRAT score reached nearly 70%. Docking simulations showed the MEV exhibiting the highest interaction and binding energies (-1,023.4 kcal/mol, -923.2 kcal/mol, and -988.3 kcal/mol) with TLR-4, MHC-I, and MHC-II receptors. Further molecular dynamics simulations demonstrated the docked complexes' remarkable stability and maximum interactions, i.e., uniform RMSD, fluctuated RMSF, and lowest binding net energy. In silico models also predict the vaccine will stimulate a variety of immunological pathways following administration. These analyses suggest the vaccine's efficacy in inducing robust immune responses against A. hydrophila. With high solubility and no predicted allergic responses or toxicity, it appears safe for administration in both healthy and A. hydrophila-infected individuals.

3D Organoids for Regenerative Endodontics

Apical periodontitis is the inflammation and destruction of periradicular tissues, mediated by microbial factors originating from the infected pulp space. This bacteria-mediated inflammatory disease is known to interfere with root development in immature permanent teeth. Current research on interventions in immature teeth has been dedicated to facilitating the continuation of root development as well as regenerating the dentin-pulp complex, but the fundamental knowledge on the cellular interactions and the role of periapical mediators in apical periodontitis in immature roots that govern the disease process and post-treatment healing is limited. The limitations in 2D monolayer cell culture have a substantial role in the existing limitations of understanding cell-to-cell interactions in the pulpal and periapical tissues. Three-dimensional (3D) tissue constructs with two or more different cell populations are a better physiological representation of in vivo environment. These systems allow the high-throughput testing of multi-cell interactions and can be applied to study the interactions between stem cells and immune cells, including the role of mediators/cytokines in simulated environments. Well-designed 3D models are critical for understanding cellular functions and interactions in disease and healing processes for future therapeutic optimization in regenerative endodontics. This narrative review covers the fundamentals of (1) the disease process of apical periodontitis; (2) the influence and challenges of regeneration in immature roots; (3) the introduction of and crosstalk between mesenchymal stem cells and macrophages; (4) 3D cell culture techniques and their applications for studying cellular interactions in the pulpal and periapical tissues; (5) current investigations on cellular interactions in regenerative endodontics; and, lastly, (6) the dental-pulp organoid developed for regenerative endodontics.

Exploring the anti-inflammatory potential of Colocasia esculenta root extract in in-vitro and in-vivo models of inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Colocasia esculenta (CE) (L.) Schott is an annual herbaceous tropical plant from the family of Araceae which has been traditionally used for the healing of various ailments such as asthma, arthritis, internal hemorrhage, diarrhea, and neurological disorders. The plant is reported to have potential anti-microbial, anti-fungal, antimetastatic, anti-hepatotoxic, and anti-lipid peroxidative activities.

AIM OF THE STUDY

The present study is designed to explore the potential anti-inflammatory property of Colocasia esculenta methanolic root extract (CEMRE) on carrageenan-induced rat paw edema and lipopolysaccharide (LPS) stimulated RAW264.7 cells.

MATERIALS AND METHODS

Carrageenan-induced rat paw edema model was used to investigate the in vivo anti-inflammatory action of CEMRE. Adult male Wistar rats (180-220 g; n = 6) were pre-treated with CEMRE (100, 200, and 400 mg/kg BW) orally before 1 h of injection of 1% carrageenan. Indomethacin (10 mg/kg BW) was given orally as the standard drug. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), nitric oxide (NO), prostaglandinE2 (PGE2), and cytokines levels were measured. Liquid chromatography-mass spectrometry (LC-MS) was done to identify the phytoconstituents present in CEMRE. The inhibitory activity of CEMRE was investigated against cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in in vitro assessment of LPS-stimulated RAW264.7 cells. The RAW 264.7 cells were pre-treated with Indomethacin (5 μM and 10 μM) and CEMRE (17 μg/ml and 34 μg/ml) followed by induction of LPS (1 μg/ml) for 24 h. Docking analyses were also performed to explore the interaction of important phytoconstituents (Sinapic acid, Acetylsalicylic acid, L-fucose, Salicylic acid, Quinic acid, Zingerone, and Gingerol) of CEMRE with COX-2 and iNOS.

RESULTS

Pre-treatment with CEMRE (400 mg/kg) could inhibit the paw inflammation significantly which was elevated due to carrageenan induction. The inhibition is comparable to that of the standard drug Indomethacin. The concentration of serum AST, ALT, ALP, NO, PGE2 and cytokines were also considerably lowered in the CEMRE-treated group as compared to the carrageenan-induced group. CEMRE (34 μg/ml) inhibited the LPS-stimulated relative expression of mRNA of COX-2 and iNOS and significantly reduced the expression of nitric oxide and prostaglandin E2. Docking analyses revealed promising interaction with low binding energies between Sinapic acid with both the target proteins COX-2 and iNOS.

CONCLUSION

Collectively, our results suggested that CEMRE exhibited effective anti-inflammatory actions on carrageenan-induced rat paw edema and LPS-treated RAW 264.7 cells by reducing the in vivo paw edema inhibition, inhibiting the serum NO, PGE2, cytokines and also reduced the in vitro production of NO, PGE2 along with expressions of mRNA COX-2 and iNOS. Molecular docking demonstrated good binding affinities among the target proteins and ligand Sinapic acid. Thus the bioactive compound from CE need to be isolated and purified.

Capsule formation around breast implants

All implants are rapidly coated by the host with glycoproteins forming a thin capsule, and this is a normal response. Where an inflammatory stimulus such as infection is present, the capsule can thicken and become microvascularised and sometimes calcified. This inflammatory stimulus can take the form of leachable chemicals from the implant, or bacteria live or dead. The presence of live bacteria can lead to biofilm development, which is part of the chronic infective, inflammatory process. Staphylococcus epidermidis and Cutibacterium acnes have been implicated in chronic infection around breast implants, and some animal models suggest their involvement in capsule contracture. Molecular methods have revealed an array of microorganisms from samples of removed capsular material, though they are extremely sensitive to contamination. The relevance of the results to capsular contracture remains poorly understood. Bacteria of low virulence are shown associated with capsular contracture and calcification, and measures beyond those conventionally applied need to be investigated to limit perioperative contamination.

Bacterial Invasion of Pulp Blood Vessels in Teeth with Symptomatic Irreversible Pulpitis

INTRODUCTION

This study described the degenerative changes and infection patterns of the pulp tissue associated with symptomatic irreversible pulpitis.

METHODS

The material consisted of 32 extracted teeth with untreated deep caries that were clinically and histologically diagnosed with irreversible pulpitis and were part of the histopathologic collection of 1 of the authors. The controls consisted of intact teeth with normal uninflamed pulps and teeth with reversible pulpitis. Teeth were processed for histopathologic and histobacteriologic analyses.

RESULTS

All teeth with irreversible pulpitis showed areas of severe acute inflammation, necrosis, microabscesses, and bacterial infection in the pulp chamber. These areas were surrounded by a chronic inflammatory infiltrate, and, at the distance, the pulp tissue was often uninflamed. Bacteria were also observed in the areas surrounding the necrotic foci, both as scattered cells through the extravascular space and at varying numbers within the blood vessel lumen. The number of bacteria and the density of the intravascular bacterial aggregations varied considerably. In one third of the cases, bacteria occurred in the lumen of venules in areas at a considerable distance from the necrotic focus in the coronal third of the root. No intravascular bacteria were noted in the middle and apical segments of the canal. No bacteria were found in the pulps of any of the control specimens.

CONCLUSIONS

Bacterial invasion and colonization of necrotic areas were observed in the pulp of all teeth with caries exposure and symptomatic irreversible pulpitis. Bacterial penetration of blood vessels occurred in all cases, suggesting that this may be an important mechanism of spread of bacterial infection through the pulp tissue in an endodontic infection.

The Effect of a Unique Region of Parvovirus B19 Capsid Protein VP1 on Endothelial Cells

Parvovirus B19 (B19V) is a widespread human pathogen possessing a high tropism for erythroid precursor cells. However, the persistence or active replication of B19V in endothelial cells (EC) has been detected in diverse human pathologies. The VP1 unique region (VP1u) of the viral capsid has been reported to act as a major determinant of viral tropism for erythroid precursor cells. Nevertheless, the interaction of VP1u with EC has not been studied. We demonstrate that recombinant VP1u is efficiently internalized by rats’ pulmonary trunk blood vessel-derived EC in vitro compared to the human umbilical vein EC line. The exposure to VP1u was not acutely cytotoxic to either human- or rat-derived ECs, but led to the upregulation of cellular stress signaling-related pathways. Our data suggest that high levels of circulating B19V during acute infection can cause endothelial damage, even without active replication or direct internalization into the cells.

Hyperresponsiveness of human gingival fibroblasts from patients with aggressive periodontitis against bacterial lipopolysaccharide

The present study aimed to investigate whether gingival fibroblasts (GFs) of patients with aggressive periodontitis (AgP) are more sensitive to lipopolysaccharide (LPS) stimulation than GFs of control subjects. AgP causes rapid periodontal destruction, including the production of cytokines [i.e. interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α] and matrix metalloproteinases (MMP)-1, -3 and -9 in AgP GFs. LPS upregulates IL-1β, IL-6, TNF-α, MMP-1, MMP-3, MMP-9 and mitochondrial reactive oxygen species (mtROS). Fibroblasts are known to be associated with immune responses to bacterial virulence factors, but the precise mechanisms underlying this severe periodontal disease are unclear. In the present study, primary human GFs of four patients with AgP and four healthy subjects were challenged in vitro with LPS from Porphyromonas gingivalis (P. gingivalis). The generation of mtROS in GFs was assessed using MitoSOX Red. The expression of genes encoding inflammatory cytokines and MMPs in GFs was analyzed using reverse transcription-quantitative polymerase chain reaction, and the expression of proteins was analyzed using ELISA and Western blotting. Human GFs of patients with AgP exhibited higher levels of mtROS, and higher mRNA and protein expression levels of proinflammatory cytokines, including IL-1β, IL-6, MMP-1, MMP-3 and MMP-9 compared with healthy human GFs following stimulation with LPS from P. gingivalis. In the present study, it was demonstrated that GFs of patients with AgP display hyperreactivity when challenged with LPS.

Bacterial Factors Targeting the Nucleus: The Growing Family of Nucleomodulins

Pathogenic bacteria secrete a variety of proteins that manipulate host cell function by targeting components of the plasma membrane, cytosol, or organelles. In the last decade, several studies identified bacterial factors acting within the nucleus on gene expression or other nuclear processes, which has led to the emergence of a new family of effectors called “nucleomodulins”. In human and animal pathogens, Listeria monocytogenes for Gram-positive bacteria and Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, Legionella pneumophila, Shigella flexneri, and Escherichia coli for Gram-negative bacteria, have led to pioneering discoveries. In this review, we present these paradigms and detail various mechanisms and core elements (e.g., DNA, histones, epigenetic regulators, transcription or splicing factors, signaling proteins) targeted by nucleomodulins. We particularly focus on nucleomodulins interacting with epifactors, such as LntA of Listeria and ankyrin repeat- or tandem repeat-containing effectors of Rickettsiales, and nucleomodulins from various bacterial species acting as post-translational modification enzymes. The study of bacterial nucleomodulins not only generates important knowledge about the control of host responses by microbes but also creates new tools to decipher the dynamic regulations that occur in the nucleus. This research also has potential applications in the field of biotechnology. Finally, this raises questions about the epigenetic effects of infectious diseases.

Early cytokine response to lethal challenge of Klebsiella pneumoniae averted the prognosis of pneumonia in FyuA immunized mice

Klebsiella pneumoniae, a multi drug resistant nosocomial pathogen is associated with pneumonia and immunization gives a hope to fight its infections. A possible vaccine candidate is the conserved protein, yersiniabactin receptor FyuA. Its expression along with the siderophore yersiniabactin increases in bacteria under iron starving conditions prevailing in lungs. In this study, the potential of recombinant FyuA of K. pneumoniae has been evaluated against lung infection in BALB/c mice. Immunization generated both humoral and cell mediated response which conferred protection against the lethal dose of bacteria. Bacterial burden in lungs reduced by 6 log₁₀ CFU/ml after 2nd day post infection as compared to control. Similarly, the levels of pro-inflammatory cytokines IL-17, TNF-α and IL-1β were also reduced significantly; reduced tissue damage was evident from histopathology of lungs in immunized mice. These results indicate the protective role of FyuA which can be a potential vaccine candidate.

Efficacy of Intranasal Administration of the Recombinant Endolysin SAL200 in a Lethal Murine Staphylococcus aureus Pneumonia Model

SAL200 is derived from a phage endolysin and is a novel candidate drug for the treatment of Staphylococcus aureus infection. We investigated the efficacy of the recombinant endolysin SAL200 in a lethal murine pneumonia model. Lethal pneumonia was established by intranasally administering a methicillin-susceptible (Newman) or methicillin-resistant (LAC) S. aureus strain into BALB/c mice. The mice were treated with a single intranasal administration of SAL200 or phosphate-buffered saline at 2 h after S. aureus infection. The survival rates were recorded until 60 h after the bacterial challenge. The bacterial loads in the lungs and blood, histopathology of lung tissues, and serum cytokine levels were evaluated following the S. aureus challenge. The SAL200-treated group and control group exhibited 90% to 95% and 10% to 40% survival rates, respectively. The bacterial loads in the lungs of the SAL200-treated group were significantly lower by ∼10-fold than those of the control group as early as 1 h after treatment. Histopathologic recovery of pneumonia was observed in the SAL200-treated mice. The cytokine levels were comparable between groups. These results suggest that direct administration of SAL200 into the lungs could be a potential adjunct treatment against severe pneumonia caused by S. aureus.

Endotoxin Contributes to Artificial Loosening of Prostheses Induced by Titanium Particles

Background

Aseptic loosening of orthopedic implants caused by wear particles is a major cause of joint replacement failure. However, the mechanism of aseptic loosening has not yet been defined. The present study explored whether endotoxin adherent on the titanium (Ti) particles contributes to aseptic loosening.

Material/Methods

Limulus amebocyte lysate detection was conducted to detect the levels of endotoxin adhered to the Ti particles. A mouse air pouches model was established and mice were divided into 4 groups and injected with phosphate-buffered saline (PBS) or Ti particles suspensions (0.1, 1, 10 mg/mL), following detection of the number of macrophages and the level of endotoxin. Scanning electron microscopy (SEM) was used to characterize the microstructures of Ti particles adhered with endotoxin.

Results

In vitro experiments showed that the level of endotoxin adhered to the Ti particles was significantly increased after adding LPS back to these “endotoxin-free” particles. In vivo experiments showed that Ti particles injection significantly increased the number of macrophages and the level of endotoxin.

Conclusions

In conclusion, these results suggest that adherent endotoxin may play an important role in aseptic loosening induced by Ti particles.

Targeting CREB-binding protein overrides LPS induced radioresistance in non-small cell lung cancer cell lines

Non-small cell lung cancer (NSCLC) has a very poor prognosis even when treated with the best therapies available today often including radiation. NSCLC is frequently complicated by pulmonary infections which appear to impair prognosis as well as therapy, whereby the underlying mechanisms are still not known. It was investigated here, whether the bacterial lipopolysaccharides (LPS) might alter the tumor cell radiosensitivity. LPS were found to induce a radioresistance but solely in cells with an active TLR-4 pathway. Proteome profiling array revealed that LPS combined with irradiation resulted in a strong phosphorylation of cAMP response element-binding protein (CREB). Inhibition of CREB binding protein (CBP) by the specific inhibitor ICG-001 not only abrogated the LPS-induced radioresistance but even led to an increase in radiosensitivity. The sensitization caused by ICG-001 could be attributed to a reduction of DNA double-strand break (DSB) repair.

It is shown that in NSCLC cells LPS leads to a CREB dependent radioresistance which is, however, reversible through CBP inhibition by the specific inhibitor ICG-001. These findings indicate that the combined treatment with radiation and CBP inhibition may improve survival of NSCLC patients suffering from pulmonary infections.

TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Pathogen-specific immune response and changes in the blood-milk barrier of the bovine mammary gland

Because of the decreasing use of antimicrobial drugs in animal food production, new treatments of infectious diseases such as mastitis are needed. This includes strategies to optimize the function of the animal's immune system. The present review discusses the components of the mammary immune response and the involvement of the blood-milk barrier during infections with different bacteria, strategies to manipulate the blood-milk barrier, and the potential to increase the efficiency of the animal's immune response. The mammary immune response is widely based on the cellular components of the innate immune system, which can be detected as an increase of the somatic cell count (SCC). During infection with Gram-negative bacteria such as , characterized by severe clinical symptoms, there is a considerable transfer of soluble blood components including immunoglobulins from blood into milk. This is not typically observed during intramammary infection with Gram-positive bacteria such as , which is typically observed as a chronic subclinical infection. We have simulated these different types of mastitis by administering cell wall components of these bacteria (i.e., lipopolysaccharide [LPS] from and lipoteichoic acid [LTA] from ). Dosages of these 2 components intramammarily administered were adjusted to induce a comparable increase in SCC. Treatment with LPS caused a comprehensive transfer of blood components including immunoglobulins into milk, whereas in the LTA-induced mastitis, only a small increase of blood components in milk occurred. The blood-milk barrier can be manipulated. Glucocorticoids such as prednisolone reduced the transfer of blood components from blood into milk while reducing the general inflammatory reaction. It is possible that this treatment also inhibits the transfer of immunoglobulins into milk, likely reducing the efficiency of the immune response. In contrast, an opening of the blood-milk barrier could be achieved by an extremely high dosage of oxytocin (e.g., 100 IU). We assume that the myoepithelial hypercontraction increases the epithelial permeability that allows an increased flux of blood components including immunoglobulins into milk. The potential for manipulating the blood-milk barrier permeability as a treatment for mastitis is possible if specific antibodies against pathogens can be efficiently transported to the infected mammary gland.

The Anti-Inflammatory Effect and Structure of EPCP1-2 from Crypthecodinium cohnii via Modulation of TLR4-NF-κB Pathways in LPS-Induced RAW 264.7 Cells

Exopolysaccharide from Crypthecodinium cohnii (EPCP1-2) is a marine exopolysaccharide that evidences a variety of biological activities. We isolated a neutral polysaccharide from the fermentation liquid of Crypthecodinium cohnii (CP). In this study, a polysaccharide that is derived from Crypthecodinium cohnii were analyzed and its anti-inflammatory effect was evaluated on protein expression of toll-like receptor 4 and nuclear factor κB pathways in macrophages. The structural characteristics of EPCP1-2 were characterized by GC (gas chromatography) and GC-MS (gas Chromatography-Mass Spectrometer) analyses. The molecular weight was about 82.5 kDa. The main chain of EPCP1-2 consisted of (1→6)-linked mannopyranosyl, (1→6)-linked glucopyranosyl, branched-chain consisted of (1→3,6)-linked galactopyranosyl and terminal consisted of t-l-Rhapyranosyl. The in vitro anti-inflammatory activity was representated through assay of proliferation rate, pro-inflammatory factor (NO) and expressions of proteins on RAW 264.7, the macrophage cell line. The results revealed that EPCP1-2 exhibited significant anti-inflammatory activity by regulating the expression of toll-like receptor 4, mitogen-activated protein kinases, and Nuclear Factor-κB protein.

Antivirals against animal viruses

Antivirals are compounds used since the 1960s that can interfere with viral development. Some of these antivirals can be isolated from a variety of sources, such as animals, plants, bacteria or fungi, while others must be obtained by chemical synthesis, either designed or random. Antivirals display a variety of mechanisms of action, and while some of them enhance the animal immune system, others block a specific enzyme or a particular step in the viral replication cycle. As viruses are mandatory intracellular parasites that use the host's cellular machinery to survive and multiply, it is essential that antivirals do not harm the host. In addition, viruses are continually developing new antiviral resistant strains, due to their high mutation rate, which makes it mandatory to continually search for, or develop, new antiviral compounds. This review describes natural and synthetic antivirals in chronological order, with an emphasis on natural compounds, even when their mechanisms of action are not completely understood, that could serve as the basis for future development of novel and/or complementary antiviral treatments.

Anti-inflammatory Activity of a High-molecular-weight Cranberry Fraction on Macrophages Stimulated by Lipopolysaccharides from Periodontopathogens

Periodontitis is a chronic inflammatory disease affecting oral tissues. The continuous, high production of cytokines by host cells triggered by periodontopathogens is thought to be responsible for the destruction of tooth-supporting tissues. Macrophages play a critical role in this host inflammatory response to periodontopathogens. The aim of this study was to investigate the effect of non-dialyzable material prepared from cranberry juice concentrate on the pro-inflammatory cytokine response of macrophages induced by lipopolysaccharides (LPS) from Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum subsp. nucleatum, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Escherichia coli. Interleukin-1 beta (IL-1β), IL-6, IL-8, tumor necrosis factor alpha (TNF-α), and Regulated on Activation Normal T-cell Expressed and Secreted (RANTES) production by macrophages treated with the cranberry fraction prior to stimulation by LPS was evaluated by ELISA. Our results clearly indicate that the cranberry fraction was a potent inhibitor of the pro-inflammatory cytokine and chemokine responses induced by LPS. This suggests that cranberry constituents may offer perspectives for the development of a new therapeutic approach to the prevention and treatment of periodontitis.

Dietary Administration of Bacillus subtilis Enhances Growth Performance, Immune Response and Disease Resistance in Cherry Valley Ducks

Given the promising results of applying Bacillus subtilis (B.subtilis) as a probiotic in both humans and animals, the aim of this study was to systematically investigate the effects of B. subtilis on growth performance, immune response and disease resistance in Cherry Valley ducks. At 28 d post-hatch (dph), ducks fed a diet with B. subtilis weighed significantly more, had higher relative immune organ weights (e.g., bursa of Fabricius, thymus, and spleen), and exhibited greater villus heights, villus height to crypt depth ratios (duodenum and jejunum), and shallower crypt depths in the duodenum than controls fed a normal diet (p < 0.05). Moreover, the major pro-inflammatory factors and antiviral proteins, as measured in the thymus and the spleen, were higher at 28 dph in ducks fed probiotics than those of 14 dph. After 28 d of feeding, the ducks were challenged with Escherichia coli (E. coli) and novel duck reovirus (NDRV), and ducks fed B. subtilis achieved survival rates of 43.3 and 100%, respectively, which were significantly greater than the control group's 20 and 83.3%. Altogether, diets with B. subtilis can improve Cherry Valley ducks' growth performance, innate immune response, and resistance against E. coli and NDRV.

Anti-Inflammatory, Anti-Osteoclastogenic and Antioxidant Effects of Malva sylvestris Extract and Fractions: In Vitro and In Vivo Studies

Given their medical importance, natural products represent a tremendous source of drug discovery. The aim of this study was to investigate Malva sylvestris L. extract and fractions and their pharmacological activities followed by chemical identification. The aqueous fraction (AF) was identified as the bioactive fraction in the in vitro and in vivo assays. The AF controlled the neutrophil migration to the peritoneal cavity by 66%, inhibited the antiedematogenic activity by 58.8%, and controlled IL-1β cytokine expression by 54%. The in vitro viability tests showed a concentration-dependent effect, where the MSE and fractions at concentrations under 10 μg/mL were non-toxic to cells. Transcriptional factors of carbonic anhydrase II (CAII), cathepsin K (Ctsk) and tartrate-resistant acid phosphatase (TRAP) were analyzed by qPCR in RAW 264.7 cell lines. The gene expression analysis showed that the AF was the only treatment that could downregulate all the study genes: CAII, Ctsk and TRAP (p<0.05). TRAP staining was used to evaluate osteoclast formation. AF treatments reduced the number of osteoclastogenesis 2.6-fold compared to the vehicle control group. Matrix metalloproteinase 9 (MMP-9) activity decreased 75% with the AF treatment. Moreover, the bioactive fraction had the ability to regulate the oxidation pathway in the ABTS (2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) assay with an activity equivalent to 1.30 μmol Trolox/g and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals 1.01 g/L. Positive ion ESI-mass spectrometry for molecular ions at m/z 611 and 633 confirmed rutin as the major compound in the AF. The AF of M. sylvestris presented anti-inflammatory, controlled osteoclastogenic mechanisms and antioxidant abilities in different in vitro and in vivo methods. In addition, we suggest that given its multi-target activity the bioactive fraction may be a good candidate in the therapy of chronic inflammatory diseases.

Cultured Mesenchymal Stem Cells Stimulate an Immune Response by Providing Immune Cells with Toll-Like Receptor 2 Ligand

Mesenchymal stem cells (MSCs) serve as supporting and regulatory cells, by providing tissues with multiple factors and are also known for their immunosuppressive capabilities. Our laboratory had previously shown that MSCs expressed toll-like receptor (TLR) 2 and are activated by its ligand Pam3Cys. TLR2 is an important component of the innate immune system, as it recognizes bacterial lipopeptides, thus priming a pro-inflammatory immune response. This study showed that Pam3Cys attached extensively to cells of both wild-type and TLR2 deficient cultured MSCs, thus, independently of TLR2. The TLR2 independent binding occurred through the adsorption of the palmitoyl moieties of Pam3Cys. It was further showed that Pam3Cys was transferred from cultured MSCs to immune cells. Moreover, Pam3Cys provided to the immune cells induced a pro-inflammatory response in vitro and in vivo. Overall, it is demonstrated herein that a TLR2 ligand bound to MSCs also through a TLR2 independent mechanism. Furthermore, the ligand incorporated by MSCs is subsequently released to stimulate an immune response both in vitro and in vivo. It is thus suggested that during bacterial infection, stromal cells may retain a reservoir of the TLR2 ligands, in a long-term manner, and release them slowly to maintain an immune response.

MALP-2, a Mycoplasma lipopeptide with classical endotoxic properties: end of an era of LPS monopoly?

Although some activities of LPS are shared by other bacterial components, for half a century LPS has been regarded as unique in displaying many pathophysiological activities. Here we report on a synthetic lipopeptide, MALP-2 from Mycoplasma fermentans , which expresses potent endotoxin-like activity and whose lethal toxicity is comparable to that of LPS. With the exception of the Limulus lysate gelation test, in which MALP-2 was approximately 1000-fold less active than LPS, the synthetic lipopeptide induced all activities tested for, and in most cases to an extent comparable to that of LPS. Unlike LPS, the biological activities of MALP-2 were expressed both in LPSresponder and in LPS-non-responder mice (BALB/c/l, C57BL10/ScCr), indicating that MALP-2 signaling, unlike that of LPS, is not transduced via the Toll-like receptor (Tlr) 4 protein. MALP-2 expressed no toxicity in normal or sensitized Tlr2 knockout (Tlr2— /—) mice indicating that its toxic activity is induced via Tlr2 signaling. The phenomenology of the lethal shock induced by MALP-2 in normal or sensitized mice, i.e. the kinetics of its development and symptoms of illness exhibited by the treated animals, was very reminiscent of the lethal shock induced by LPS.

Toll-like receptor-2 transduces signals for NF-κB activation, apoptosis and reactive oxygen species production

The innate immune system coordinates the inflammatory response to pathogens. To do so, cells of the innate immune system must rapidly discriminate between self and non-self. All bacteria express membrane-associated lipoproteins. These molecules activate cells of the innate immune system to initiate host defense mechanisms. However, it is currently unknown how the innate immune system recognizes bacterial lipoproteins. Here, we describe that in response to bacterial lipoprotein, human Toll-like receptor-2 activates three different cellular responses: nuclear factor-κB dependent transcription, programmed cell death and reactive oxygen species production. We propose that Toll-like receptor-2 fulfils multiple roles in the genesis of the immune response to bacterial pathogens.

Identification of meningococcal LPS as a major monocyte activator in IL-10 depleted shock plasmas and CSF by blocking the CD14-TLR4 receptor complex

We have examined the in vitro stimulatory effects of lipopolysaccharide (LPS)-containing samples (meningococcal shock plasma, n = 10; non-shock plasma, n = 10; cerebrospinal fluid (CSF), n = 7) before and after immunodepletion of interleukin (IL)-10 in a monocyte target assay. We also studied the stimulatory effects of plasma collected from 3 patients with lethal septicemia caused by Streptococcus pneumoniae without detectable LPS but with 100-fold increased levels of heat-shock protein 70 (HSP70). HSP70 may, like LPS, activate monocytes via the Toll-like receptor 4 (TLR4). The samples were analyzed for LPS, tumor necrosis factor (TNF)-α, IL-10 and HSP70; applied on human monocytes (purity > 95%) before and after IL-10 immunodepletion, in the absence or presence of CD14 blocking mAb (60bca) or the lipid A antagonist, Rhodobacter sphaeroides diphosphoryl lipid A (RsDPLA) which blocks TLR4. Monocyte activation was measured by increased TNF-α secretion and tissue factor (TF) up-regulation by monocyte procoagulant activity (PCA). There was a positive correlation between patientplasma LPS levels ( n = 10) and increases in TNF-α secretion by the monocytes after immunodepletion of IL-10 ( r = 0.82). Pretreatment of the monocytes with mAbCD14 or RsDPLA reduced TNF-α secretion to median 5% and 12%, respectively, of the levels before the receptor complex was blocked. The median levels of HSP70 were 543 ng/ml (range, 468—962 ng/ml) in pneumococcal shock plasma, 81.5 ng/ml (range, 41—331 ng/ml) in meningococcal shock plasma and 24 ng/ml (range, < 0.8—41 ng/ml) in meningococcal non-shock plasma. Pneumococcal septic shock plasmas with significantly higher levels of HSP70 ( P < 0.05) did not induce TNF-α secretion in the monocytes. The results strongly suggest that LPS in meningococcal shock plasma is the major activator of monocytes whereas HSP70 (in plasma concentrations up to 963 ng/ml) does not activate monocytes in this assay.

Particle Disease: A Current Review of the Biological Mechanisms in Periprosthetic Osteolysis After Hip Arthroplasty

Background:

Inflammatory responses to wear debris cause osteolysis that leads to aseptic prosthesis loosening and hip arthroplasty failure. Although osteolysis is usually associated with aseptic loosening, it is rarely seen around stable implants. Aseptic implant loosening is a simple radiologic phenomenon, but a complex immunological process. Particulate debris produced by implants most commonly causes osteolysis, and this is called particle-associated periprosthetic osteolysis (PPO).

Objective:

The objective of this review is to outline the features of particle-associated periprosthetic osteolysis to allow the physician to recognise this condition and commence early treatment, thereby optimizing patient outcome.

Methods:

A thorough literature search was performed using available databases, including Pubmed, to cover important research published covering particle-associated PPO.

Results:

Although osteolysis causes bone resorption, clinical, animal, and in vitro studies of particle bioreactivity suggest that particle-associated PPO represents the culmination of several biological reactions of many cell types, rather than being caused solely by the osteoclasts. The biological activity is highly dependent on the characteristics and quantity of the wear particles.

Conclusion:

Despite advances in total hip arthroplasty (THA), particle-associated PPO and aseptic loosening continue to be major factors that affect prosthetic joint longevity. Biomarkers could be exploited as easy and objective diagnostic and prognostic targets that would enable testing for osteolysis after THA. Further research is needed to identify new biomarkers in PPO. A comprehensive understanding of the underlying biological mechanisms is crucial for developing new therapeutic interventions to reverse or suppress biological responses to wear particles.

Combination Therapy of LysGH15 and Apigenin as a New Strategy for Treating Pneumonia Caused by Staphylococcus aureus

Pneumonia is one of the most prevalent Staphylococcus aureus-mediated diseases, and the treatment of this infection is becoming challenging due to the emergence of multidrug-resistant S. aureus, especially methicillin-resistant S. aureus (MRSA) strains. It has been reported that LysGH15, the lysin derived from phage GH15, displays high efficiency and a broad lytic spectrum against MRSA and that apigenin can markedly diminish the alpha-hemolysin of S. aureus. In this study, the combination therapy of LysGH15 and apigenin was evaluated in vitro and in a mouse S. aureus pneumonia model. No mutual adverse influence was detected between LysGH15 and apigenin in vitro. In animal experiments, the combination therapy showed a more effective treatment effect than LysGH15 or apigenin monotherapy (P < 0.05). The bacterial load in the lungs of mice administered the combination therapy was 1.5 log units within 24 h after challenge, whereas the loads in unprotected mice or mice treated with apigenin or LysGH15 alone were 10.2, 4.7, and 2.6 log units, respectively. The combination therapy group showed the best health status, the lowest ratio of wet tissue to dry tissue of the lungs, the smallest amount of total protein and cells in the lung, the fewest pathological manifestations, and the lowest cytokine level compared with the other groups (P < 0.05). With regard to its better protective efficacy, the combination therapy of LysGH15 and apigenin exhibits therapeutic potential for treating pneumonia caused by MRSA. This paper reports the combination therapy of lysin and natural products derived from traditional Chinese medicine.

Gamma-irradiated resveratrol negatively regulates LPS-induced MAPK and NF-κB signaling through TLR4 in macrophages

Resveratrol was irradiated at various doses of 15, 30, 50, and 70kGy for the development of physiological functionalities through modification of the structural properties. Gamma irradiation induced a decrease in the resveratrol peak, and the appearance of several new peaks by gamma irradiation was gradually increased up to 70kGy. Gamma-irradiated resveratrol did not exert cytotoxicity to macrophages in dose ranges from 15 to 70kGy; therefore, 70kGy gamma-irradiated resveratrol was used as the maximum dose throughout subsequent experiments. Treatment of LPS-stimulated macrophages with 70kGy gamma-irradiated resveratrol resulted in a dose-dependent decrease in iNOS-mediated NO, PGE2, and pro-inflammatory cytokine level, such as TNF-α, IL-6 and IL-1β. 70kGy gamma-irradiated resveratrol significantly inhibited cyclooxygenase-2 levels, as well as the expression of cell surface molecules, such as CD80 and CD86, in LPS-induced macrophages. Furthermore, the inhibitory action of these pro-inflammatory mediators occurred through an inhibition of MAPKs (ERK1/2, p38 and JNK) and NF-κB signaling pathways based on a toll-like receptor 4 in macrophages, which may be closely mediated with the radiolysis products of resveratrol transformed by gamma-irradiation. From these findings, it seems likely that gamma irradiation can be an effective tool for a reduction of the toxicity and play a potent role in the treatment of inflammatory disease.

Changes in peripheral blood leucocytes of sheep experimentally infected with Mycoplasma agalactiae

Contagious agalactia is a serious disease of small ruminants affecting mainly mammary glands, joints and eyes. In sheep, the main aetiological agent is Mycoplasma agalactiae (Ma) whose abilities to persist in the target organs are known. Since there is no information on the effect of acute and chronic Ma infection on circulating leucocytes, the present study was designed to monitor granulocytes, monocytes, T and B lymphocytes, by flow cytometry, in female lactating sheep nasally infected with Ma. A profound depletion of leucocytes was observed from day 5 to day 34 post infection (p.i.). In particular, while the granulocytes returned to baseline levels by day 12 p.i., the monocytes remained significantly low until day 20 p.i. The infection caused a prolonged depletion of peripheral T lymphocytes (both CD4(+) and CD8(+)) while B lymphocytes remained unaltered throughout the study. Mycoplasma agalactiae was detected by real-time PCR in several anatomical sites (ear, nose and milk) from day 2-5 p.i. until the end of the study (i.e., day 50 p.i.) while a transient bacteraemia was observed from day 5 to day 12 p.i. The leucopenia observed following intranasal Ma infection is likely due to leucocyte infiltration within the target organs.

Antioxidant effects of cranberry powder in lipopolysaccharide treated hypercholesterolemic rats

This study was conducted to investigate the effects of cranberry power on antioxidant defense system in rats fed an atherogenic diet and injected with lipopolysaccharide (LPS). Sprague-Dawley rats were divided into the following 5 groups: normal diet+saline (NS), atherogenic diet+saline (AS), atherogenic diet+LPS (AL), atherogenic diet with 5% cranberry powder+LPS (AL-C5), and atherogenic diet with 10% cranberry powder+LPS (AL-C10). Total antioxidant status measured by ferric reducing ability of plasma (FRAP) was significantly reduced by LPS injection (24%) and was restored by the cranberry powder treatment (P<0.05). In addition, the mean level of plasma total phenolics was significantly decreased by LPS injection (P<0.05) and tended to be increased when cranberry powder was incorporated in to the diet. Activity of serum superoxide dismutase (SOD) tended to be lowered by LPS injection and declined further in cranberry powder fortified groups. Overall results indicate that dietary cranberry powder may provide appropriate antioxidants to counter the diminished antioxidant status induced by exposing hypercholesterolemic rats to LPS.

Bacterial factors exploit eukaryotic Rho GTPase signaling cascades to promote invasion and proliferation within their host

Actin cytoskeleton is a main target of many bacterial pathogens. Among the multiple regulation steps of the actin cytoskeleton, bacterial factors interact preferentially with RhoGTPases. Pathogens secrete either toxins which diffuse in the surrounding environment, or directly inject virulence factors into target cells. Bacterial toxins, which interfere with RhoGTPases, and to some extent with RasGTPases, catalyze a covalent modification (ADPribosylation, glucosylation, deamidation, adenylation, proteolysis) blocking these molecules in their active or inactive state, resulting in alteration of epithelial and/or endothelial barriers, which contributes to dissemination of bacteria in the host. Injected bacterial virulence factors preferentially manipulate the RhoGTPase signaling cascade by mimicry of eukaryotic regulatory proteins leading to local actin cytoskeleton rearrangement, which mediates bacterial entry into host cells or in contrast escape to phagocytosis and immune defense. Invasive bacteria can also manipulate RhoGTPase signaling through recognition and stimulation of cell surface receptor(s). Changes in RhoGTPase activation state is sensed by the innate immunity pathways and allows the host cell to adapt an appropriate defense response.

The virulence of Streptococcus mutans and the ability to form biofilms

In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?

Phenol-soluble modulins: novel virulence-associated peptides of staphylococci

 Phenol-soluble modulins (PSMs), a novel class of small peptides with an amphipathic α-helical structure and strong surfactant-like properties, are produced by most staphylococci, especially pathogenic Staphylococcus aureus and Staphylococcus epidermidis. PSMs can: induce the production of proinflammatory cytokines; recruit, activate and lyse neutrophils to help staphylococci evade immune damage; lyse erythrocytes and are associated with the hemolysis of staphylococcal disease; facilitate the structuring and detachment of staphylococcal biofilms and disseminate biofilm-associated infection; and kill competing microbes and act as weapons in interbacterial warfare. Therefore, PSMs are considered to be critical virulence-associated factors and to play important roles in the pathogenesis of staphylococci. This review summarizes the classification, structure, expression regulation and biological functions of PSMs. The possible means to prevent PSM-associated diseases are also outlined in order to emphasize the need to investigate PSMs as potential targets for drug and vaccine design against staphylococcal infections.

The pathogenicity of the Streptococcus genus

Streptococcus infections are still one of the important problems facing contemporary medicine. As the World Health Organization (WHO) warns, Streptococcus pneumoniae is responsible for the highest number of pneumonia cases all over the world. Despite an increasing number of pneumococcal vaccinations, incidences of disease connected to this pathogen's infection stay at the same level, which is related to a constantly increasing number of infections caused by nonvaccinal serotypes. Unfortunately, the pathogenicity of bacteria of the Streptococcus genus is also connected to species considered to be physiological flora in humans or animals and, additionally, new species exhibiting pathogenic potential have been discovered. This paper presents an opinion concerning the epidemiology of streptococci infections based on case studies and other publications devoted to this problem. It also sheds new light based on recent reports on the prevention of protective vaccinations application in the case of streptococci infections.

Procyanidin dimer B2-mediated IRAK-M induction negatively regulates TLR4 signaling in macrophages

Polyphenolic compounds have been found to possess a wide range of physiological activities that may contribute to their beneficial effects against inflammation-related diseases; however, the molecular mechanisms underlying this anti-inflammatory activity are not completely characterized, and many features remain to be elucidated. In this study, we investigated the molecular basis for the down-regulation of toll-like receptor 4 (TLR4) signal transduction by procyanidin dimer B2 (Pro B2) in macrophages. Pro B2 markedly elevated the expression of the interleukin (IL)-1 receptor-associated kinase (IRAK)-M protein, a negative regulator of TLR signaling. Lipopolysaccharide (LPS)-induced expression of cell surface molecules (CD80, CD86, and MHC class I/II) and production of pro-inflammatory cytokines (tumor necrosis factor-α, IL-1β, IL-6, and IL-12p70) were inhibited by Pro B2, and this action was prevented by IRAK-M silencing. In addition, Pro B2-treated macrophages inhibited LPS-induced activation of mitogen-activated protein kinases such as extracellular signal-regulated kinase 1/2, p38, and c-Jun N-terminal kinase and the translocation of nuclear factor κB and p65 through IRAK-M. We also found that Pro B2-treated macrophages inactivated naïve T cells by inhibiting LPS-induced interferon-γ and IL-2 secretion through IRAK-M. These novel findings provide new insights into the understanding of negative regulatory mechanisms of the TLR4 signaling pathway and the immune-pharmacological role of Pro B2 in the immune response against the development and progression of many chronic diseases.

Protective effect of phosphatidylcholine on lipopolysaccharide-induced acute inflammation in multiple organ injury

Soybean polyunsaturated phosphatidylcholine (PC) is thought to exert anti-inflammatory activities and has potent effects in attenuating acute renal failure and liver dysfunction. The aim of this study was to investigate the effects of PC in protecting multiple organ injury (MOI) from lipopolysaccharide (LPS). Six groups of rats (N=8) were used in this study. Three groups acted as controls and received only saline, hydrocortisone (HC, 6 mg/kg, i.v.) or PC (600 mg/kg, i.p.) without LPS (15 mg/kg, i.p.) injections. Other 3 groups, as the test groups, were administered saline, HC or PC in the presence of LPS. Six hours after the LPS injection, blood and organs (lung, liver and kidney) were collected from each group to measure inflammatory cytokines and perform histopathology and myeloperoxidase (MPO) assessment. Serum cytokines (TNF-α, IL-6 and IL-10) and MPO activities were significantly increased, and significant histopathological changes in the organs were observed by LPS challenge. These findings were significantly attenuated by PC or HC. The treatment with PC or HC resulted in a significant attenuation on the increase in serum levels of TNF-α and IL-6, pro-inflammatory cytokines, while neither PC nor HC significantly attenuated serum levels of IL-10, anti-inflammatory cytokine. In the organs, the enhanced infiltration of neutrophils and expression of ED2 positive macrophage were attenuated by PC or HC. Inductions of MPO activity were also significantly attenuated by PC or HC. From the findings, we suggest that PC may be a functional material for its use as an anti-inflammatory agent.

Anti-inflammatory activity of edible brown alga Saccharina japonica and its constituents pheophorbide a and pheophytin a in LPS-stimulated RAW 264.7 macrophage cells

Anti-inflammatory activity of Saccharina japonica and its active components was evaluated via in vitro inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) expression in RAW 264.7 murine macrophage cells. Since the methanolic extract of S. japonica showed strong anti-inflammatory activity, it was fractionated with several solvents. Among the fractions, the ethyl acetate fraction demonstrated the highest inhibition of LPS-induced NO production (IC50=25.32μg/mL), followed by the CH2Cl2 fraction (IC50=75.86μg/mL). Considering the yield and anti-inflammatory potential together, the CH2Cl2 fraction was selected for chromatographic separation to yield two active porphyrin derivatives, pheophorbide a and pheophytin a, together with an inactive fucoxanthin. In contrast to fucoxanthin, pheophorbide a and pheophytin a showed dose-dependent inhibition against LPS-induced NO production at nontoxic concentrations in RAW 264.7 cells. Both compounds also suppressed the expression of iNOS proteins, while they did not inhibit the COX-2 expression in LPS-stimulated macrophages. These results indicate that pheophorbide a and pheophytin a are two important candidates of S. japonica as anti-inflammatory agents which can inhibit the production of NO via inhibition of iNOS protein expression. Thus, these compounds hold great promise for use in the treatment of various inflammatory diseases.

Anthrax Lethal Toxin Inhibits the Production of Proinflammatory Cytokines

In previous studies, we have found that anthrax lethal toxin (LeTx) induces apoptosis in both murine macrophages and human peripheral blood mononuclear cells (PBMCs). In this study, we further report that bacterial cell wall (CW) components of Bacillus (B.) anthracis are powerful inducers of proinflammatory cytokines from the PBMCs. These effects are deprived when the LeTx is present. The major causative element for this suppression is lethal factor (LF) rather than protective antigen (PA). These results indicate that the roles of LeTx in anthrax pathogenesis, particularly its effects on cytokine production, should be reevaluated as our findings and other reports are controversial to the conventional concept.

Treponema denticola interactions with host proteins

Oral Treponema species, most notably T. denticola, are implicated in the destructive effects of human periodontal disease. Progress in the molecular analysis of interactions between T. denticola and host proteins is reviewed here, with particular emphasis on the characterization of surface-expressed and secreted proteins of T. denticola involved in interactions with host cells, extracellular matrix components, and components of the innate immune system.

The virulence regulator Agr controls the staphylococcal capacity to activate human neutrophils via the formyl peptide receptor 2

The Agr quorum-sensing system represents the master regulator for staphylococcal virulence factors and is known to have a strong impact on the release of pathogen-associated molecular pattern (PAMP) molecules. Among the various staphylococcal PAMPs, phenol-soluble modulin (PSM) peptides have attracted increasing interest because they are crucial for staphylococcal virulence and have neutrophil-recruiting properties. The latter depend on recognition of PSMs by the neutrophil formyl peptide receptor 2 (FPR2/ALX), for which PSMs are highly efficient agonists. We demonstrate that Agr inactivation in Staphylococcus aureus or S. epidermidis leads to strongly reduced neutrophil responses, which is in agreement with the previously reported strict control of PSM expression by Agr. Agr had a distinct and profound impact on activation of FPR2/ALX but not of the related FPR1 receptor that senses bacterial formylated peptides. S. epidermidis PSMs had similar FPR2/ALX-activating properties but differed in their dependence on N-terminal formylation compared to S. aureus PSMs. Moreover, S. aureus and S. epidermidis PSMs upregulated the neutrophil complement receptor CD11b via FPR2/ALX stimulation in an Agr-dependent fashion. Hence, Agr controls the capacity of staphylococcal pathogens to activate FPR2/ALX-dependent neutrophil responses, underscoring the crucial role of FPR2/ALX and PSMs in staphylococcus-host interaction.

MK615: a new therapeutic approach for the treatment of oral disease

The oral cavity is inhabited by over 500 different bacterial species. Dental caries and periodontitis are major bacterial infectious diseases in the oral cavity. Prunus mume Sieb. et Zucc., which is a variety of Japanese apricot known as Ume in Japanese, has been a traditional Japanese medicine for centuries, and is a familiar and commonly consumed food. The health benefits of Ume are now being widely recognized. Recent studies showed that MK615, an extract of compounds from Ume, has strong anticancer and anti-inflammatory effects. However, the potential role of MK615 in the antimicrobial field remains unknown. Therefore, we hypothesize that MK615 has antimicrobial activities against a range of oral bacterial pathogens. Here, we show that MK615 may be a potent inhibitor of the growth of some oral bacteria and an inhibitor of biofilm formation by Streptococcus mutans, the principal etiological agent of human dental caries. Our findings suggest that MK615 has potential as a therapeutic agent for treating and preventing oral diseases such as dental caries and periodontitis.

Antibacterial and anti-inflammatory activities of 4-hydroxycordoin: potential therapeutic benefits

4-Hydroxycordoin (1), a natural isopentenyloxychalcone, is a plant secondary metabolite that is relatively rare. Since there are very few reports about the biological activities of 1, its potential benefits for periodontal disease were investigated. A marked and dose-dependent antibacterial activity of 1 was observed against the three major periodontal pathogens, Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia. Moreover, compound 1 showed an antiadhesion effect, since it inhibited attachment of P. gingivalis to oral epithelial cells. Finally, using a macrophage model, the ability of 1 to inhibit the secretion of inflammatory mediators induced by Aggregatibacter actinomycetemcomitans lipopolysaccharide was demonstrated. The anti-inflammatory effect observed was associated with reduced activation of the nuclear factor-κB (NF-κB) p65 and activator protein-1 (AP-1) pathways.

Expression of UDP-glucuronosyltransferase 1A6 isoform in Caco-2 cells stimulated with lipopolysaccharide

Glucuronidation is an important metabolic process of detoxification in all vertebrates. The reaction is catalyzed by a multigene family of UDP-glucuronosyltransferases (UGTs) able to convert many xenobiotics and endobiotics (hydrophobic substances) to inactive, water-soluble glucuronides. The UGTs play a protective role, facilitating the elimination of potentially toxic metabolites via urine, bile and feces; therefore, impairment of UGTs may have important toxicological consequences. The regulation of UGTs during bacterial infection or inflammation is not well described. In this study, we investigated the in vitro effect of lipopolysaccharide (LPS) on the expression of the UGT1A6 isoform in human colon carcinoma Caco-2 cells. Results demonstrated a significant down-regulation of UGT1A6 expression, both in terms of mRNA and protein levels, and a reduced UGT activity after LPS exposure of cell cultures, suggesting a role for endotoxins on UGT regulation mechanisms.

Important aspects of Toll-like receptors, ligands and their signaling pathways

Due to the rapid increase of new information on the multiple roles of Toll-like receptors (TLRs), this paper reviews several main properties of TLRs and their ligands and signaling pathways. The investigation of pathogen infections in knockout mice suggests that specific TLRs play a key role in the activation of immune responses. Although the investigation of TLR biology is just beginning, a number of important findings are emerging. This review focuses on the following seven aspects of this emerging field: (a) a history of TLR and ligand studies; (b) the molecular basis of recognition by TLRs: TLR structures, pathogen-associated molecular pattern binding sites, TLR locations and functional responses; (c) cell types in TLR expression; (d) an overview of TLRs and their ligands: expression and ligands of cell-surface TLRs and of intracellular TLRs; (e) TLR-signaling pathways; (f) discussion: TLRs control of innate and adaptive systems; the trafficking of intracellular TLRs to endolysosomes; investigation of TLRs in regulating microRNA; investigation of crystal structure of TLRs with ligand binding; incidence of infectious diseases associated with single nucleotide polymorphisms (SNPs) in TLR genes; risk of cancer related to SNPs in TLR genes; TLR-ligand mediated anti-cancer effects; and TLR-ligand induced chronic inflammation and tumorigenesis; and (g) conclusions.

Structure-activity relationships in toll-like receptor-2 agonistic diacylthioglycerol lipopeptides

The N-termini of bacterial lipoproteins are acylated with a (S)-(2,3-bisacyloxypropyl)cysteinyl residue. Lipopeptides derived from lipoproteins activate innate immune responses by engaging Toll-like receptor 2 (TLR2) and are highly immunostimulatory and yet without apparent toxicity in animal models. The lipopeptides may therefore be useful as potential immunotherapeutic agents. Previous structure-activity relationships in such lipopeptides have largely been obtained using murine cells, and it is now clear that significant species-specific differences exist between human and murine TLR responses. We have examined in detail the role of the highly conserved Cys residue as well as the geometry and stereochemistry of the Cys-Ser dipeptide unit. (R)-Diacylthioglycerol analogues are maximally active in reporter gene assays using human TLR2. The Cys-Ser dipeptide unit represents the minimal part-structure, but its stereochemistry was found not to be a critical determinant of activity. The thioether bridge between the diacyl and dipeptide units is crucial, and replacement by an oxoether bridge results in a dramatic decrease in activity.

MK615 attenuates Porphyromonas gingivalis lipopolysaccharide-induced pro-inflammatory cytokine release via MAPK inactivation in murine macrophage-like RAW264.7 cells

The Japanese apricot, known as Ume in Japanese, has been a traditional Japanese medicine for centuries, and is a familiar and commonly consumed food. The health benefits of Ume are now being widely recognized and have been strengthened by recent studies showing that MK615, an extract of compounds from Ume, has strong anticancer and anti-inflammatory effects. However, the potential role of MK615 in the periodontal field remains unknown. Here, we found that MK615 significantly reduced the production of pro-inflammatory mediators (tumor necrosis factor-alpha and interleukin-6) induced by Porphyromonas gingivalis lipopolysaccharide (LPS), a major etiological agent in localized chronic periodontitis, in murine macrophage-like RAW264.7 cells. MK615 markedly inhibited the phosphorylation of ERK1/2, p38MAPK, and JNK, which is associated with pro-inflammatory mediator release pathways. Moreover, MK615 completely blocked LPS-triggered NF-kappaB activation. The present results suggest that MK615 has potential as a therapeutic agent for treating inflammatory diseases such as periodontitis.