Primary dengue haemorrhagic fever in patients from northeast of Brazil is associated with high levels of interferon-β during acute phase

Dengue is an acute febrile disease caused by the mosquito-borne dengue virus (DENV) that according to clinical manifestations can be classified as asymptomatic, mild or severe dengue. Severe dengue cases have been associated with an unbalanced immune response characterised by an over secretion of inflammatory cytokines. In the present study we measured type I interferon (IFN-I) transcript and circulating levels in primary and secondary DENV infected patients. We observed that dengue fever (DF) and dengue haemorrhagic fever (DHF) patients express IFN-I differently. While DF and DHF patients express interferon-α similarly (52,71 ± 7,40 and 49,05 ± 7,70, respectively), IFN- β were associated with primary DHF patients. On the other hand, secondary DHF patients were not able to secrete large amounts of IFN- β which in turn may have influenced the high-level of viraemia. Our results suggest that, in patients from our cohort, infection by DENV serotype 3 elicits an innate response characterised by higher levels of IFN- β in the DHF patients with primary infection, which could contribute to control infection evidenced by the low-level of viraemia in these patients. The present findings may contribute to shed light in the role of innate immune response in dengue pathogenesis.

HCF-1 self-association via an interdigitated Fn3 structure facilitates transcriptional regulatory complex formation.

Host-cell factor 1 (HCF-1) is an unusual transcriptional regulator that undergoes a process of proteolytic maturation to generate N- (HCF-1(N)) and C- (HCF-1(C)) terminal subunits noncovalently associated via self-association sequence elements. Here, we present the crystal structure of the self-association sequence 1 (SAS1) including the adjacent C-terminal HCF-1 nuclear localization signal (NLS). SAS1 elements from each of the HCF-1(N) and HCF-1(C) subunits form an interdigitated fibronectin type 3 (Fn3) tandem repeat structure. We show that the C-terminal NLS recruited by the interdigitated SAS1 structure is required for effective formation of a transcriptional regulatory complex: the herpes simplex virus VP16-induced complex. Thus, HCF-1(N)-HCF-1(C) association via an integrated Fn3 structure permits an NLS to facilitate formation of a transcriptional regulatory complex.

An in vitro iron superoxide dismutase inhibitor decreases the parasitemia levels of Trypanosoma cruzi in BALB/c mouse model during acute phase.

In order to identify new compounds to treat Chagas disease during the acute phase with higher activity and lower toxicity than the reference drug benznidazole (Bz), two hydroxyphthalazine derivative compounds were prepared and their trypanocidal effects against Trypanosoma cruzi were evaluated by light microscopy through the determination of IC50 values. Cytotoxicity was determined by flow cytometry assays against Vero cells. In vivo assays were performed in BALB/c mice, in which the parasitemia levels were quantified by fresh blood examination; the assignment of a cure was determined by reactivation of blood parasitemia levels after immunosuppression. The mechanism of action was elucidated at metabolic and ultra-structural levels, by (1)H NMR and TEM studies. Finally, as these compounds are potentially capable of causing oxidative damage in the parasites, the study was completed, by assessing their activity as potential iron superoxide dismutase (Fe-SOD) inhibitors. High-selectivity indices observed in vitro were the basis of promoting one of the tested compounds to in vivo assays. The tests on the murine model for the acute phase of Chagas disease showed better parasitemia inhibition values than those found for Bz. Compound 2 induced a remarkable decrease in the reactivation of parasitemia after immunosuppression. Compound 2 turned out to be a great inhibitor of Fe-SOD. The high antiparasitic activity and low toxicity together with the modest costs for the starting materials render this compound an appropriate molecule for the development of an affordable anti-Chagas agent.

Describing ancient horizontal gene transfers at the nucleotide and gene levels by comparative pathogenicity island genometrics.

MOTIVATION: Lateral gene transfer is a major mechanism contributing to bacterial genome dynamics and pathovar emergence via pathogenicity island (PAI) spreading. However, since few of these genomic exchanges are experimentally reproducible, it is difficult to establish evolutionary scenarios for the successive PAI transmissions between bacterial genera. Methods initially developed at the gene and/or nucleotide level for genomics, i.e. comparisons of concatenated sequences, ortholog frequency, gene order or dinucleotide usage, were combined and applied here to homologous PAIs: we call this approach comparative PAI genometrics. RESULTS: YAPI, a Yersinia PAI, and related islands were compared with measure evolutionary relationships between related modules. Through use of our genometric approach designed for tracking codon usage adaptation and gene phylogeny, an ancient inter-genus PAI transfer was oriented for the first time by characterizing the genomic environment in which the ancestral island emerged and its subsequent transfers to other bacterial genera.

Mitofusins 1/2 and ERRalpha expression are increased in human skeletal muscle after physical exercise

Mitochondrial impairment is hypothesized to contribute to the pathogenesis of insulin resistance. Mitofusin (Mfn) proteins regulate the biogenesis and maintenance of the mitochondrial network, and when inactivated, cause a failure in the mitochondrial architecture and decreases in oxidative capacity and glucose oxidation. Exercise increases muscle mitochondrial content, size, oxidative capacity and aerobic glucose oxidation. To address if Mfn proteins are implicated in these exercise-induced responses, we measured Mfn1 and Mfn2 mRNA levels, pre-, post-, 2 and 24 h post-exercise. Additionally, we measured the expression levels of transcriptional regulators that control mitochondrial biogenesis and functions, including PGC-1alpha, NRF-1, NRF-2 and the recently implicated ERRalpha. We show that Mfn1, Mfn2, NRF-2 and COX IV mRNA were increased 24 h post-exercise, while PGC-1alpha and ERRalpha mRNA increased 2 h post-exercise. Finally, using in vitro cellular assays, we demonstrate that Mfn2 gene expression is driven by a PGC-1alpha programme dependent on ERRalpha. The PGC-1alpha/ERRalpha-mediated induction of Mfn2 suggests a role of these two factors in mitochondrial fusion. Our results provide evidence that PGC-1alpha not only mediates the increased expression of oxidative phosphorylation genes but also mediates alterations in mitochondrial architecture in response to aerobic exercise in humans

REST Regulates Oncogenic Properties of Glioblastoma Stem Cells.

Glioblastoma multiforme (GBM) tumors are the most common malignant primary brain tumors in adults. Although many GBM tumors are believed to be caused by self-renewing, glioblastoma-derived stem-like cells (GSCs), the mechanisms that regulate self-renewal and other oncogenic properties of GSCs are only now being unraveled. Here we showed that GSCs derived from GBM patient specimens express varying levels of the transcriptional repressor repressor element 1 silencing transcription factor (REST), suggesting heterogeneity across different GSC lines. Loss- and gain-of-function experiments indicated that REST maintains self-renewal of GSCs. High REST-expressing GSCs (HR-GSCs) produced tumors histopathologically distinct from those generated by low REST-expressing GSCs (LR-GSCs) in orthotopic mouse brain tumor models. Knockdown of REST in HR-GSCs resulted in increased survival in GSC-transplanted mice and produced tumors with higher apoptotic and lower invasive properties. Conversely, forced expression of exogenous REST in LR-GSCs produced decreased survival in mice and produced tumors with lower apoptotic and higher invasive properties, similar to HR-GSCs. Thus, based on our results, we propose that a novel function of REST is to maintain self-renewal and other oncogenic properties of GSCs and that REST can play a major role in mediating tumorigenicity in GBM. STEM CELLS 2012;30:405-414.

The circadian clock modulates renal sodium handling.

The circadian clock contributes to the control of BP, but the underlying mechanisms remain unclear. We analyzed circadian rhythms in kidneys of wild-type mice and mice lacking the circadian transcriptional activator clock gene. Mice deficient in clock exhibited dramatic changes in the circadian rhythm of renal sodium excretion. In parallel, these mice lost the normal circadian rhythm of plasma aldosterone levels. Analysis of renal circadian transcriptomes demonstrated changes in multiple mechanisms involved in maintaining sodium balance. Pathway analysis revealed the strongest effect on the enzymatic system involved in the formation of 20-HETE, a powerful regulator of renal sodium excretion, renal vascular tone, and BP. This correlated with a significant decrease in the renal and urinary content of 20-HETE in clock-deficient mice. In summary, this study demonstrates that the circadian clock modulates renal function and identifies the 20-HETE synthesis pathway as one of its principal renal targets. It also suggests that the circadian clock affects BP, at least in part, by exerting dynamic control over renal sodium handling.

Discovery and refinement of loci associated with lipid levels.

Levels of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and total cholesterol are heritable, modifiable risk factors for coronary artery disease. To identify new loci and refine known loci influencing these lipids, we examined 188,577 individuals using genome-wide and custom genotyping arrays. We identify and annotate 157 loci associated with lipid levels at P < 5 × 10(-8), including 62 loci not previously associated with lipid levels in humans. Using dense genotyping in individuals of European, East Asian, South Asian and African ancestry, we narrow association signals in 12 loci. We find that loci associated with blood lipid levels are often associated with cardiovascular and metabolic traits, including coronary artery disease, type 2 diabetes, blood pressure, waist-hip ratio and body mass index. Our results demonstrate the value of using genetic data from individuals of diverse ancestry and provide insights into the biological mechanisms regulating blood lipids to guide future genetic, biological and therapeutic research.

Increased cardiac angiotensin II levels induce right and left ventricular hypertrophy in normotensive mice.

Angiotensin II is a potent arterial vasoconstrictor and induces hypertension. Angiotensin II also exerts a trophic effect on cardiomyocytes in vitro. The goals of the present study were to document an in vivo increase in cardiac angiotensins in the absence of elevated plasma levels or hypertension and to investigate prevention or regression of ventricular hypertrophy by renin-angiotensin system blockade. We demonstrate that high cardiac angiotensin II is directly responsible for right and left ventricular hypertrophy. We used transgenic mice overexpressing angiotensinogen in cardiomyocytes characterized by cardiac hypertrophy without fibrosis and normal blood pressure. Angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade prevent or normalize ventricular hypertrophy. Surprisingly, in control mice, receptor blockade decreases tissue angiotensin II despite increased plasma levels. This suggests that angiotensin II may be protected from metabolization by binding to its receptor. Blocking of the angiotensin II type 1 receptor rather than enhanced stimulation of the angiotensin II type 2 receptor may prevent remodeling and account for the beneficial effects of angiotensin antagonists.

The Role of AtPHO1 in the Guard Cell Movements of Arabidopsis thaliana

In plants, stomatal opening and closing are driven by ion fluxes that cause changes in guard cell turgor and volume, a process that is in turn regulated by complex environ¬mental and hormonal signals such as light and the phytohormone abscisic acid (ABA). With this study, we present genetic evidence that stomatal movements in response to ABA are influenced by PHOl expression in guard cells of Arabidopsis thaliana. PHOl is a phosphate exporter involved in phosphate loading into the root xylem ves¬sels and, as a result, the phol mutant is characterized by low shoot phosphate lev¬els. In leaves, PHOl was found expressed at higher level in guard cells, and was quickly up-regulated following treatment with ABA. The phol mutant was unaffected in ROS production following ABA treatment, and in stomatal movements in response to different light cues, high extracellular calcium, auxin, and fusicoccin. However, stomatal movements in response to ABA treatment were severely impaired, both in terms of induction of closure and inhibition of opening. Stomatal movements in re¬sponse to hydrogen peroxide and reduced CO2 was altered as well. Micro-grafting a phol shoot scion onto wild-type root stock resulted in plants with normal shoot growth and Pi content, but failed to restore normal stomatal response to ABA treat-ment, showing that the impairment was not a simple pleiotropic consequence of phos¬phate deficiency. PHOl knockdown using RNAi specifically in guard cells of wild-type plants caused a reduced stomatal response to ABA. In agreement, specific expression of PHOl in guard cells of phol plants complemented the mutant guard cell phenotype and re-established ABA sensitivity, although full functional complementation was co- dependent on shoot Pi sufficiency. Down-regulation of PHOl in guard cells did not alter the expression of ABA marker genes, indicating that PHOl does not affect the ABA signal transduction cascade at the transcriptional level. Together, these data reveal an important role for phosphate and PHOl action in the stomatal response to ABA. Résumé L'ouverture et la fermeture des stomates des plantes sont des mouvements contrôlés par des flux d'ions causant des fluctuations de la turgescence des cellules de garde. Ce procédé est en retour régulé par des signaux environnementaux et hormonaux complexes, comme la lumière et l'hormone végétale acide abscissique (ABA). Nous présentons ici des preuves génétiques montrant que les mouvements stomatiques en réponse à l'ABA sont influencés par l'expression de PHOl dans les cellules de garde d'Arabidopsis thaliana. PHOl est un exporteur de phosphate, impliqué dans l'efflux de phosphate des cellules corticales racinaires vers les vaisseaux de xylème. En con¬séquence, le mutant phol est caractérisé par de faibles niveaux de phosphate dans les parties aériennes. Dans les feuilles, PHOl est exprimé préférentiellement dans les cellules de garde, comparé au mésophylle, et est rapidement induit par le traitement à l'ABA. Le mutant phol n'est pas affecté dans la perception de l'ABA, dans la pro¬duction de ROS en réponse à l'ABA, et dans la réponse des stomates aux traitements de lumière, à l'auxine, à la fusiccocine, et la forte concentration extracellulaire de cal¬cium. En revanche, les mouvements de stomates en réponse aux traitements à l'ABA sont fortement affectés, dans l'induction de la fermeture des stomates comme dans l'inhibition de leur ouverture. De plus, les mouvements de stomates en réponse au péroxyde d'hydrogène et à la diminution du CO2 sont aussi compromis. La création de micro-greffes composées d'une partie aérienne phol greffés sur un système racinaire sauvage génère des plantes avec une croissance et une teneur en phosphate normale, mais ne permet pas de restaurer la réponse des stomates à l'ABA, ce qui démontre que le défaut de réponse à l'ABA n'est pas une simple conséquence pléiotropique de la carence en phosphate. La répression par RNAi de l'expression de PHOl dans les stomates de plantes sauvages provoque une réduction de la réponse des stomates à l'ABA, mais n'affecte pas la réponse de gènes marqueurs à l'ABA, ce qui suggère que PHOl n'agit pas au niveau transcriptionnel. Parallèlement, l'expression de PHOl dans les cellules de gardes de mutants phol complémente le phénotype stomatique mutant et rétablit la réponse à l'ABA, bien que la totale complémentation nécessite l'apport normal de phosphate aux parties aériennes. Ensemble, ces résultats révè¬lent l'influence importante de PHOl et du phosphate dans la réponse des stomates à l'ABA.

Comparisons of serum vitamin d levels, status, and determinants in populations with and without chronic kidney disease not requiring renal dialysis: a 24-hour urine collection population-based study.

OBJECTIVE: Vitamin D deficiency is frequent in the general population and might be even more prevalent among populations with kidney failure. We compared serum vitamin D levels, vitamin D insufficiency/deficiency status, and vitamin D level determinants in populations without chronic kidney disease (CKD) and with CKD not requiring renal dialysis. DESIGN AND METHODS: This was a cross-sectional, multicenter, population-based study conducted from 2010 to 2011. Participants were from 10 centers that represent the geographical and cultural diversity of the Swiss adult population (≥15 years old). INTERVENTION: CKD was defined using estimated glomerular filtration rate and 24-hour albuminuria. Serum vitamin D was measured by liquid chromatography-tandem mass spectrometry. Statistical procedures adapted for survey data were used. MAIN OUTCOME MEASURE: We compared 25-hydroxy-vitamin D (25(OH)D) levels and the prevalence of vitamin D insufficiency/deficiency (serum 25(OH)D < 30 ng/mL) in participants with and without CKD. We tested the interaction of CKD status with 6 a priori defined attributes (age, sex, body mass index, walking activity, serum albumin-corrected calcium, and altitude) on serum vitamin D level or insufficiency/deficiency status taking into account potential confounders. RESULTS: Overall, 11.8% (135 of 1,145) participants had CKD. The 25(OH)D adjusted means (95% confidence interval [CI]) were 23.1 (22.6-23.7) and 23.5 (21.7-25.3) ng/mL in participants without and with CKD, respectively (P = .70). Vitamin D insufficiency or deficiency was frequent among participants without and with CKD (75.3% [95% CI 69.3-81.5] and 69.1 [95% CI 53.9-86.1], P = .054). CKD status did not interact with major determinants of vitamin D, including age, sex, BMI, walking minutes, serum albumin-corrected calcium, or altitude for its effect on vitamin D status or levels. CONCLUSION: Vitamin D concentration and insufficiency/deficiency status are similar in people with or without CKD not requiring renal dialysis.

Levels of PSP toxins in bivalves exposed to natural blooms of Alexandrium minutum in Catalan harbours

The development, validation, comparison and evaluation of analytical methods for marine toxins rely on the availability of toxic material. Within the project JACUMAR PSP, our interest is mainly focused on autochthonous bivalve species with the toxic profile of Alexandrium minutum, since this is the principal species involved regionally in PSP outbreaks. Mussels and oysters were exposed during few days in the harbor of Vilanova i la Geltrú, to blooms reaching a maximum A. minutum concentration of 200,000 cells L-1 in 2008, and 40,000 and 800,000 cells L-1, in 2009. Mussels, oysters and clams were exposed to one bloom of 22,000 cells L-1 in the harbor of Cambrils in 2009. In all situations higher toxic levels analyzed by HPLC-FD with postcolumn oxidation were observed in mussels (i.e. 1,200-2,500 μg eq. STX kg-1) than in oysters (i.e. 60-800 μg eq. STX kg-1) exposed to the same bloom. Blooms with higher concentrations of A. minutum did not correspond to higher levels of PSP toxins in bivalves. These differences may be explained by differences in A. minutum population dynamics, toxin production or in the physiological state or behaviour of shellfish. These results confirm that mussels concentrate more PSP toxins from A. minutum than oysters and clams.