Mechanisms of interleukin-6 protection against ischemia-reperfusion injury in rat liver

Numerous animal studies simulating liver injury have demonstrated that interleukin-6 (IL-6) exerts a protective effect. This study was designed to further analyze the molecular mechanisms underlying the protective role of IL-6 in a rat model of liver ischemia/reperfusion injury. We show that IL-6: (i) at high doses reduces cell damage which occurs in ischemic-reperfused liver, while at low doses displays only a limited protective capacity, (ii) anticipates and enhances hepatocyte compensatory proliferation seen in ischemic-reperfused liver also at a low, more pharmacologically acceptable dose, (iii) sustains the acute phase response which is dampened in ischemic-reperfused liver, (iv) strengthens the heat shock-stress response shown by ischemic-reperfused liver and (v) overcomes the dysfunctions of the unfolding protein response found in ischemic-reperfused liver. We also show that IL-6-enhanced STAT3 activation probably plays a crucial role in the potentiation of the different protective pathways activated in ischemic-reperfused liver. Our data confirm that IL-6 is a potential therapeutic in liver injury of different etiologies and reveal novel mechanisms by which IL-6 sustains liver function after ischemia/reperfusion injury.     

Monomorphism of human cytochrome c

Cytochrome c (Cyt c) has key roles in both mitochondrial electron transfer and apoptosis onset and is therefore likely undergoing a strong selective pressure against amino acid variation. Nevertheless, a phylogenetically fast amino acid replacement rate in the Cyt c of species of the anthropoid primate lineage was recently reported. We therefore looked for the presence of nonsynonymous single nucleotide polymorphisms (nsSNPs) in the human Cyt c (HGNC approved gene symbol: CYCS), which, given its cellular constraints, could have important functional consequences, and found a large number of putative nsSNPs reported in the dbSNP database. We then subjected these putative SNPs to experimental validation by sequencing the Cyt c gene in a panel of 95 individuals assumed as a standard reference of the human population diversity. Surprisingly, none of the putative SNPs survived experimental validation. We conclude that non-rare allelic variants of the Cyt c protein are absent in the human populations analyzed in this study.     

Mutant PrP suppresses glutamatergic neurotransmission in cerebellar granule neurons by impairing membrane delivery of VGCC α(2)δ-1 Subunit

How mutant prion protein (PrP) leads to neurological dysfunction in genetic prion diseases is unknown. Tg(PG14) mice synthesize a misfolded mutant PrP which is partially retained in the neuronal endoplasmic reticulum (ER). As these mice age, they develop ataxia and massive degeneration of cerebellar granule neurons (CGNs). Here, we report that motor behavioral deficits in Tg(PG14) mice emerge before neurodegeneration and are associated with defective glutamate exocytosis from granule neurons due to impaired calcium dynamics. We found that mutant PrP interacts with the voltage-gated calcium channel α(2)δ-1 subunit, which promotes the anterograde trafficking of the channel. Owing to ER retention of mutant PrP, α(2)δ-1 accumulates intracellularly, impairing delivery of the channel complex to the cell surface. Thus, mutant PrP disrupts cerebellar glutamatergic neurotransmission by reducing the number of functional channels in CGNs. These results link intracellular PrP retention to synaptic dysfunction, indicating new modalities of neurotoxicity and potential therapeutic strategies.     

Impact of Fungicides on the Diversity and Function of Non-target Ammonia-Oxidizing Microorganisms Residing in a Litter Soil Cover

Litter soil cover constitutes an important micro-ecosystem in sustainable viticulture having a key role in nutrient cycling and serving as a habitat of complex microbial communities. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are known to regulate nitrification in soil while little is known regarding their function and diversity in litter. We investigated the effects of two fungicides, penconazole and cyprodinil, commonly used in vineyards, on the function and diversity of total and active AOB and AOA in a microcosm study. Functional changes measured via potential nitrification and structural changes assessed via denaturating gradient gel electrophoresis (DGGE) at the DNA and RNA levels were contrasted with pesticide dissipation in the litter layer. The latter was inversely correlated with potential nitrification, which was temporarily inhibited at the initial sampling dates (0 to 21?days) when nearly 100?% of the applied pesticide amounts was still present in the litter. Fungicides induced changes in AOB and AOA communities with RNA-DGGE analysis showing a higher sensitivity. AOA were more responsive to pesticide application compared to AOB. Potential nitrification was less sensitive to the fungicides and was restored faster than structural changes, which persisted. These results support the theory of microbial redundancy for nitrification in a stressed litter environment.     

Evidence of host-associated populations of Cryptosporidium parvum in Italy

Recent studies have revealed extensive genetic variation among isolates of Cryptosporidium parvum, an Apicomplexan parasite that causes gastroenteritis in both humans and animals worldwide. The parasite's population structure is influenced by the intensity of transmission, the host-parasite interaction, and husbandry practices. As a result, C. parvum populations can be panmictic, clonal, or even epidemic on both a local scale and a larger geographical scale. To extend the study of C. parvum populations to an unexplored region, 173 isolates of C. parvum collected in Italy from humans and livestock (calf, sheep, and goat) over a 10-year period were genotyped using a multilocus scheme based on 7 mini- and microsatellite loci. In agreement with other studies, extensive polymorphism was observed, with 102 distinct multilocus genotypes (MLGs) identified among 173 isolates. The presence of linkage disequilibrium, the confinement of MLGs to individual farms, and the relationship of many MLGs inferred using network analysis (eBURST) suggest a predominantly clonal population structure, but there is also evidence that part of the diversity can be explained by genetic exchange. MLGs from goats were found to differ from bovine and sheep MLGs, supporting the existence of C. parvum subpopulations. Finally, MLGs from isolates collected between 1997 and 1999 were also identified as a distinct subgroup in principal-component analysis and eBURST analysis, suggesting a continuous introduction of novel genotypes in the parasite population.     

Comparison of Microarray Platforms for Measuring Differential MicroRNA Expression in Paired Normal/Cancer Colon Tissues

Background

Microarray technology applied to microRNA (miRNA) profiling is a promising tool in many research fields; nevertheless, independent studies characterizing the same pathology have often reported poorly overlapping results. miRNA analysis methods have only recently been systematically compared but only in few cases using clinical samples.

Methodology/Principal Findings

We investigated the inter-platform reproducibility of four miRNA microarray platforms (Agilent, Exiqon, Illumina, and Miltenyi), comparing nine paired tumor/normal colon tissues. The most concordant and selected discordant miRNAs were further studied by quantitative RT-PCR. Globally, a poor overlap among differentially expressed miRNAs identified by each platform was found. Nevertheless, for eight miRNAs high agreement in differential expression among the four platforms and comparability to qRT-PCR was observed. Furthermore, most of the miRNA sets identified by each platform are coherently enriched in data from the other platforms and the great majority of colon cancer associated miRNA sets derived from the literature were validated in our data, independently from the platform. Computational integration of miRNA and gene expression profiles suggested that anti-correlated predicted target genes of differentially expressed miRNAs are commonly enriched in cancer-related pathways and in genes involved in glycolysis and nutrient transport.

Conclusions

Technical and analytical challenges in measuring miRNAs still remain and further research is required in order to increase consistency between different microarray-based methodologies. However, a better inter-platform agreement was found by looking at miRNA sets instead of single miRNAs and through a miRNAs – gene expression integration approach.     

Soil Bacterial Diversity Screening Using Single 16S rRNA Gene V Regions Coupled with Multi-Million Read Generating Sequencing Technologies

The novel multi-million read generating sequencing technologies are very promising for resolving the immense soil 16S rRNA gene bacterial diversity. Yet they have a limited maximum sequence length screening ability, restricting studies in screening DNA stretches of single 16S rRNA gene hypervariable (V) regions. The aim of the present study was to assess the effects of properties of four consecutive V regions (V3-6) on commonly applied analytical methodologies in bacterial ecology studies. Using an in silico approach, the performance of each V region was compared with the complete 16S rRNA gene stretch. We assessed related properties of the soil derived bacterial sequence collection of the Ribosomal Database Project (RDP) database and concomitantly performed simulations based on published datasets. Results indicate that overall the most prominent V region for soil bacterial diversity studies was V3, even though it was outperformed in some of the tests. Despite its high performance during most tests, V4 was less conserved along flanking sites, thus reducing its ability for bacterial diversity coverage. V5 performed well in the non-redundant RDP database based analysis. However V5 did not resemble the full-length 16S rRNA gene sequence results as well as V3 and V4 did when the natural sequence frequency and occurrence approximation was considered in the virtual experiment. Although, the highly conserved flanking sequence regions of V6 provide the ability to amplify partial 16S rRNA gene sequences from very diverse owners, it was demonstrated that V6 was the least informative compared to the rest examined V regions. Our results indicate that environment specific database exploration and theoretical assessment of the experimental approach are strongly suggested in 16S rRNA gene based bacterial diversity studies.     

Biomarkers of Good EULAR Response to the B Cell Depletion Therapy in All Seropositive Rheumatoid Arthritis Patients: Clues for the Pathogenesis

Objective

To find out whether a high number of auto-antibodies can increase the probability of a “good-EULAR response” and to identify the possible biomarkers of response in seropositive rheumatoid arthritis (RA) patients undergoing the B cell depletion therapy (BCDT).

Patients and Methods

One hundred and thirty-eight patients with long standing RA (LSRA), 75% non or poorly responsive to one or more TNFα blockers, all seropositive for at least one autoantibody (AAB) (RF-IgM, RF-IgA, RF-IgG, anti-MCV, ACPA-IgG, ACPA-IgA, ACPA-IgM) received one full course of BCDT. The major outcomes (moderate or good-EULAR response) were assessed after 6 months of therapy. The IL6 and BAFF levels were also determined.

Results

At a 6-month follow-up, 33 (23.9%) of the RA patients achieved a good EULAR response. Having up to 5-AABs positivity increased the chances for treatment response. After a logistic regression analysis, however, only 4 baseline factors arose as associated with a good-EULAR response: no steroid therapy (OR = 6.25), a lymphocyte count <1875/uL (OR = 10.74), a RF-IgG level >52.1 IU/ml (OR = 8.37) and BAFF levels <1011 pg/ml (OR = 7.38). When all the AABs, except for RF-IgM and ACPA-IgG, were left in the analysis, the two final predictors were no-steroid therapy and low lymphocyte count.

Discussion

The number of AABs increased the chances of being a “good-EULAR” responder. The only predictors, however, at the baseline of a good response in this seropositive cohort of RA patients were 2 simple variables – no steroids and lymphocyte count – and two laboratory assays – IgG-RF and BAFF.