Immunoregulatory potential of exopolysaccharide from Lactobacillus rhamnosus KL37: effects on the production of inflammatory mediators by mouse macrophages

The ability to produce exopolysaccharides (EPS) is widespread among lactobacilli including Lactobacillus rhamnosus, the commonly used probiotic bacteria. Exopolysaccharides are a major component of the bacterial biofilm with a well‐documented impact on adherence of bacteria to host cells. However, their immunoregulatory properties are unknown. The aim of this study was to examine the immunostimulatory potential of EPS derived from L. rhamnosus KL37. We investigated the effect of EPS on the production of inflammatory mediators by mouse peritoneal macrophages and compared it with the effect of Lipopolysaccharide (LPS). Exopolysaccharides, at concentrations higher than those of LPS, stimulated production of both pro‐inflammatory (TNF‐α, IL‐6, IL‐12) and anti‐inflammatory (IL‐10) cytokines. Interestingly, analysis of the balance of TNF‐α/IL‐10 production showed a potential pro‐inflammatory effect of EPS. Furthermore, our data demonstrate that exposure of macrophages to LPS induced a state of hyporesponsiveness, as indicated by reduced production of TNF‐α after restimulation with either LPS or EPS (‘cross‐tolerance’). By contrast, EPS could make cells tolerant only to subsequent stimulation by the same stimulus. We also examined the relationship between TNF‐α production and activation of mitogen‐activated protein kinases (MAPKs) by EPS and LPS. Pretreatment of macrophages with specific inhibitors of p38 and ERK MAPKs reduced TNF‐α production induced by both stimuli to the same extent. In conclusion, these data demonstrate that EPS can effectively stimulate production of inflammatory mediators by macrophages in vitro. However, to predict whether EPS could be clinically useful as an immunomodulatory agent, further in vivo studies with highly purified EPS are necessary.     

SMN-assisted assembly of snRNP-specific Sm cores in trypanosomes

Spliceosomal small nuclear ribonucleoproteins (snRNPs) in trypanosomes contain either the canonical heptameric Sm ring (U1, U5, spliced leader snRNPs), or variant Sm cores with snRNA-specific Sm subunits (U2, U4 snRNPs). Searching for specificity factors, we identified SMN and Gemin2 proteins that are highly divergent from known orthologs. SMN is splicing-essential in trypanosomes and nuclear-localized, suggesting that Sm core assembly in trypanosomes is nuclear. We demonstrate in vitro that SMN is sufficient to confer specificity of canonical Sm core assembly and to discriminate against binding to nonspecific RNA and to U2 and U4 snRNAs. SMN interacts transiently with the SmD3B subcomplex, contacting specifically SmB. SMN remains associated throughout the assembly of the Sm heteroheptamer and dissociates only when a functional Sm site is incorporated. These data establish a novel role of SMN, mediating snRNP specificity in Sm core assembly, and yield new biochemical insight into the mechanism of SMN activity.     

A European network for virtual microscopy—design,implementation and evaluation of performance

Web-based virtual microscopy has enabled new applications within pathology. Here, we introduce and evaluate a network of academic servers, designed to maximize image accessibility to users from all regions of Europe. Whole-slide imaging was utilized to digitize the entire slide set (n = 154) for the slide seminars of the 21st European Congress of Pathology. The virtual slides were mirrored to five academic servers across Europe using a novel propagation method. Functionality was implemented that automatically selects the fastest server connection in order to optimize the slide-viewing speed (). Results show that during 6 months of monitoring the uptime of the network was 100%. The average viewing speed with the network was 3.1 Mbit/s, as compared to 1.9 Mbit/s using single servers. A good viewing speed (>2Mbit/s) was observed in 32 of 37 countries (86%), compared to 25 of 37 (68%) using single servers. Our study shows that implementing a virtual microscopy network spanning a large geographical area is technically feasible. By utilizing existing academic networks and cost-minimizing image compression, it is also economically feasible. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Association between vascular endothelial growth factor gene polymorphisms and age-related macular degeneration in a Polish population

The pathogenesis of age-related macular degeneration (AMD) is thought to be determined by an array of environmental and genetic factors. The association of increased expression of vascular endothelial growth factor (VEGF) with AMD, especially the wet form of AMD, was reported in several studies. The VEGF gene is highly polymorphic and some of its polymorphisms may affect its expression. In our work, we searched for an association between the −460C> (rs833061) and −634G>C (rs2010963) polymorphisms of the VEGF gene and the occurrence of AMD and its dry and wet forms. We have chosen these polymorphisms because they were shown to be significant in other studies and we previously showed their association with diabetic retinopathy. A total of 401 individuals were enrolled in this study: 136 controls, and 88 patients with dry and 177 with wet AMD. The polymorphisms were determined with DNA from peripheral blood lymphocytes by allele-specific and restriction fragment length polymorphism polymerase chain reaction. The significance of the polymorphisms was assessed by multiple logistic regression, producing odds ratios (ORs) and 95% confidence intervals (CIs). We observed a weak association (OR 2.90) between AMD occurrence and the C/T genotype of the −460C>T polymorphism. An association (OR 3.77) between the C/T genotype of the −460C>T polymorphism and the occurrence of dry AMD was observed. The T/T genotype considerably lowered the risk of dry AMD (OR 0.19). Dry AMD was associated with the C/C genotype of the −634G>C polymorphism (OR 3.68). Another weak association (OR 2.63) was found between the C/T genotype of the −460C>T polymorphism and the occurrence of wet AMD. The occurrence of AMD was correlated with the presence of the combined C/T–G/G genotype of both polymorphisms (OR 2.41), whereas the T/T–G/G and T/T–G/C genotypes exerted a protective effect against the disease (OR 0.22 and 0.48, respectively). The presence of the C/T–G/G and C/T–C/C combined genotypes increased the risk of dry AMD (OR 2.08 and 3.77, respectively), whereas the presence of the T/T–G/G and T/T–G/C genotypes decreased the risk (OR 0.15 and 0.28, respectively). In the wet form of AMD, the combined genotype C/T–G/G slightly favored the disease (OR 2.61) and the T/T–G/G genotype had a protective effect (OR 0.25). Analysis of haplotypes of both polymorphisms yielded similar results for AMD in general as well as for the dry and wet forms of the disease: the CG haplotype favored both forms of AMD, whereas the TG haplotype protected against both forms of AMD. The results obtained indicate that the −460C>T and −634G>C polymorphisms of the VEGF gene may be associated with the dry and wet forms of AMD in a Polish population.     

Obstetric consequences of uncontrolled gestational diabetes--a case study

This paper presents a case of a pregnant woman who was admitted to the obstetrics and gynecology department because of a new onset of uncontrolled diabetes in 27 weeks gestation. The maternal and fetal diabetic complications suggested a chronic character of the disease which must have been undiagnosed before pregnancy. Many of the co-existing infections caused a life-threatening ketoacidosis. Fortunately with the adequate treatment it was possible to ensure appropriate birth weight of the newborn baby despite the ultrasound markers for LGA (Large For Gestational Age) observed during pregnancy. Intensive insulin therapy was obligatorily continued by the mother after the delivery.     

Severe bronchopulmonary dysplasia – incidence and predictive factors in a prospective,multicenter study in very preterm infants with respiratory distress syndrome

Background: Severe bronchopulmonary dysplasia (BPD) remains a major complication of prematurity and can have significant impact on long-term pulmonary sequelae and adverse neurodevelopmental outcomes.

Objective: To assess the incidence and evaluate the predictive factors for severe BPD in very preterm infants with respiratory distress syndrome.

Methods: Of the 846 premature infants born at ≤32-week gestation who developed respiratory distress syndrome (RDS), 707 infants with known oxygen dependency at 36 weeks gestational age were included in the analysis of BPD incidence. With univariate and multiple logistic regression models we evaluated the risk factors for the development of severe BPD and calculated odds ratios (ORs).

Results: The overall incidence of BPD was 45.2%. Severe BPD accounted for 6%, with morbidity pertaining mainly to infants <29-week gestation (incidence 10%). The risk factors for severe BPD included male gender (OR 3.02 95%CI 1.30–7.46), intubation in the delivery room (OR 2.57, 95%CI 1.00–7.18), and invasive ventilation >7 days (OR 7.05, 95%CI 2.63–22.4). The protective factors were early continuous positive airway pressure (CPAP) in the univariate analysis and receiving surfactant <15?min after birth in the multivariate model.

Conclusions: Mechanical ventilation >7 days is the most prevalent risk factor for severe BPD. CPAP initiated in the delivery room and early surfactant are key preventive measures.     

Prognostic value of 5-microRNA based signature in T2-T3N0 colon cancer

The role of adjuvant chemotherapy in stage T2-T3N0 colon cancer (CC) is controversial and there are currently no reliable factors allowing for individual selection of patients with high risk of relapse for such therapy. We searched for microRNA-based signature with prognostic significance in this group. We assessed by qRT-PCR expression of 754 microRNAs (miRNAs) in tumour samples from 85 stage pT2-3N0 CC patients treated with surgery alone. MiRNA expression was compared between two groups of patients: 40 and 45 patients who did and did not develop distant metastases after resection, respectively. Additionally, miRNA expression was compared between CC and normal colon mucosa samples and between the mismatch repair (MMR) competent and deficient tumours. Low expression of miR-1300 and miR-939 was significantly correlated with shorter distant metastasis-free survival (DMFS) in Cox univariate analysis (p.adjusted = 0.049). The expression signature of five miRNAs (miR-1296, miR-135b, miR-539, miR-572 and miR-185) was found to be prognostic [p = 1.28E?07, HR 8.4 (95 % CI: 3.81–18.52)] for DMFS and cross-validated in a leave-one-out analysis, with the sensitivity and specificity of 74 and 78 %, respectively. The expression of miR-592 was significantly associated with the MMR status (p.adjusted <0.01). The expression of several novel miRNAs were found to be tumour specific, e.g. miR-888, miR-523, miR-18b, miR-302a, miR-423-5p, miR-582-3p (p < 0.05). We developed a miRNA expression signature that may be predictive for the risk of distant relapse in early stage CC and confirmed previously reported association between miR-592 expression and MMR status.     

Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation

Objective

Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge.

Methods

We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM?C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM.

Results

Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM?C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge.

Conclusions

Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

     

Discussions and decisions of the 2012–2014 International Committee on Taxonomy of Viruses (ICTV) Filoviridae Study Group,January 2012–June 2013

The International Committee on Taxonomy of Viruses (ICTV) Filoviridae Study Group prepares proposals on the classification and nomenclature of filoviruses to reflect current knowledge or to correct disagreements with the International Code of Virus Classification and Nomenclature (ICVCN). In recent years, filovirus taxonomy has been corrected and updated, but parts of it remain controversial, and several topics remain to be debated. This article summarizes the decisions and discussion of the currently acting ICTV Filoviridae Study Group since its inauguration in January 2012.