Zinc Binding to Tau Influences Aggregation Kinetics and Oligomer Distribution

Metal ions are well known modulators of protein aggregation and are key players in Alzheimer’s Disease, being found to be associated to pathologic protein deposits in diseased brains. Therefore, understanding how metals influence amyloid aggregation is critical in establishing molecular mechanisms that underlie disease onset and progression. Here, we report data on the interaction of full-length human Tau protein with calcium and zinc ions, evidencing that Tau self-assembly is differently regulated, depending on the type of bound metal ion. We established that Tau binds 4 Zn²⁺ and 1 Ca²⁺ per monomer while using native mass spectrometry analysis, without inducing order or substantial conformational changes in the intrinsically disordered Tau, as determined by structural analysis using circular dichroism and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopies. However, Tau aggregation is found to proceed differently in the calcium- and -zinc bound forms. While the rate of aggregation, as determined from thioflavin-T (ThT) fluorescence kinetics, is highly increased in both cases, the reaction proceeds via different mechanisms, as evidenced by the absence of the lag phase in the reaction of zinc-bound Tau. Monitoring Tau aggregation using native mass spectrometry indeed evidenced a distinct distribution of Tau conformers along the reaction, as confirmed by dynamic light scattering analysis. We propose that such differences arise from zinc binding at distinct locations within the Tau sequence that prompt both the rapid formation of seeding oligomers through interactions at high affinity sites within the repeat domains, as well as amorphous aggregation, through low affinity interactions with residues elsewhere in the sequence, including at the fuzzy coat domain.

Vitis vinifera ‘Pinot noir’ leaves as a source of bioactive nutraceutical compounds

V. vinifera ‘Pinot noir’ leaves have a high content of biologically active phytochemical compounds of interest for pharmaceutical and food industries.

One-pot stapling of interchain disulfides of antibodies using an isobutylene motif

Stable monoclonal antibodies are generated by the mild and efficient re-bridging of interchain disulfides using an isobutylene motif. Effector functions and pharmacokinetics of the stapled antibodies are maintained at a similar level as their native forms.

Evening and morning alterations in Obstructive Sleep Apnea red blood cell proteome

This article presents proteomics data referenced in [1] Using proteomics-based evaluation of red blood cells (RBCs), we have identified differentially abundant proteins associated with Obstructive Sleep Apnea Syndrome (OSA). RBCs were collected from peripheral blood of patients with moderate/severe OSA or snoring at pre- (evening) and post-night (morning) polysomnography, so that proteome variations between these time points could be assessed. RBC cytoplasmic fraction depleted of hemoglobin, using Hemovoid^™ system, were analyzed by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE), the 2D image software-based analyzed and relevant differentially abundant proteins identified by mass spectrometry (MS). MS identified 31 protein spots differentially abundant corresponding to 21 unique proteins possibly due to the existence of post-translational modification regulations. Functional analysis by bioinformatics tools indicated that most proteins are associated with catalytic, oxidoreductase, peroxidase, hydrolase, ATPase and anti-oxidant activity. At morning a larger numbers of differential proteins including response to chemical stimulus, oxidation reduction, regulation of catalytic activity and response to stress were observed in OSA. The data might support further research in OSA biomarker discovery and validation.

Evening and morning peroxiredoxin-2 redox/oligomeric state changes in obstructive sleep apnea red blood cells: Correlation with polysomnographic and metabolic parameters

We have examined the effects of Obstructive Sleep Apnea (OSA) on red blood cell (RBC) proteome variation at evening/morning day time to uncover new insights into OSA-induced RBC dysfunction that may lead to OSA manifestations. Dysregulated proteins mainly fall in the group of catalytic enzymes, stress response and redox regulators such as peroxiredoxin 2 (PRDX2). Validation assays confirmed that at morning the monomeric/dimeric forms of PRDX2 were more overoxidized in OSA RBC compared to evening samples. Six month of positive airway pressure (PAP) treatment decreased this overoxidation and generated multimeric overoxidized forms associated with chaperone/transduction signaling activity of PRDX2. Morning levels of overoxidized PRDX2 correlated with polysomnographic (PSG)-arousal index and metabolic parameters whereas the evening level of disulfide-linked dimer (associated with peroxidase activity of PRDX2) correlated with PSG parameters. After treatment, morning overoxidized multimer of PRDX2 negatively correlated with fasting glucose and dopamine levels. Overall, these data point toward severe oxidative stress and altered antioxidant homeostasis in OSA RBC occurring mainly at morning time but with consequences till evening. The beneficial effect of PAP involves modulation of the redox/oligomeric state of PRDX2, whose mechanism and associated chaperone/transduction signaling functions deserves further investigation. RBC PRDX2 is a promising candidate biomarker for OSA severity and treatment monitoring, warranting further investigation and validation.

The effect of folic acid supplementation with ferrous sulfate on the linear and ponderal growth of children aged 6-24 months: a randomized controlled trial

BACKGROUND/OBJECTIVES

Studies evaluating the effect of folic acid supplementation, either alone or in combination with iron, on the linear and ponderal growth of children are practically nonexistent. The aim of this study was to assess the effect of folic acid supplementation with ferrous sulfate on both linear growth and weight gain in anemic and nonanemic children attending Municipal Daycare Centers in Goiania, State of Goias, Brazil.

SUBJECTS/METHODS

A double-blind, randomized, controlled trial was conducted on 188 children aged 6-24 months. The effects of ferrous sulfate and folic acid supplementation were evaluated using the analysis of variance procedure, based on a double factorial model with two factors of fixed effects (folic acid supplementation and ferrous sulfate supplementation), adjusted for initial weight. The level of significance was 0.05.

RESULTS

The children who received folic acid supplementation showed greater weight gain than the monthly average weight gain of those not given the supplement (P=0.026). This effect was independent of the dose of ferrous sulfate (P for interaction=0.693). Folic acid supplementation increased the gain of weight-for-age Z-score when compared with the placebo group (P=0.018), independent of the dose of ferrous sulfate.

CONCLUSION

Folic acid had no effect on linear growth. The use of folic acid supplementation increased the monthly average weight gain and the gain in weight-for-age Z-score compared with the placebo group. This effect was independent of the dose of ferrous sulfate.

Effects of occupational exposure to tobacco smoke: is there a link between environmental exposure and disease?

In a previous study, evidence was provided that indoor secondhand tobacco smoke (SHS) air pollution remains high in Lisbon restaurants where smoking is allowed, regardless of the protective measures used. The aim of this study was to determine in these locations the levels of polycyclic aromatic hydrocarbons (PAH) associated with the particulate phase of SHS (PPAH), a fraction that contains recognized carginogens, such as benzo[a]pyrene (BaP). Data showed that restaurant smoking areas might contain PPAH levels as high as 110 ng/m(3), a value significantly higher than that estimated for nonsmoking areas (30 ng/m(3)) or smoke-free restaurants (22 ng/m(3)). The effective exposure to SHS components in restaurant smoking rooms was confirmed as cotinine levels found in workers' urine. Considering that all workers exhibited normal lung function, eventual molecular changes in blood that might be associated with occupational exposure to SHS and SHS-associated PPAH were investigated by measurement of two oxidative markers, total antioxidant status (TAS) and 8-hydroxyguanosine (8-OHdG) in plasma and serum, respectively. SHS-exposed workers exhibited higher mean levels of serum 8-OHdG than nonexposed workers, regardless of smoking status. By using a proteomics approach based on 2D-DIGE-MS, it was possible to identify nine differentially expressed proteins in the plasma of SHS-exposed nonsmoker workers. Two acute-phase inflammation proteins, ceruloplasmin and inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), were predominant. These two proteins presented a high number of isoforms modulated by SHS exposure with the high-molecular-weight (high-MW) isoforms decreased in abundance while low-MW isoforms were increased in abundance. Whether these expression profiles are due to (1) a specific proteolytic cleavage, (2) a change on protein stability, or (3) alterations on post-translational modification pattern of these proteins remains to be investigated. Considering that these events seem to precede the first symptoms of tobacco-related diseases, our findings might contribute to elucidation of early SHS-induced pathogenic mechanisms and constitute a useful tool for monitoring the effects of SHS on occupationally exposed individuals such as those working in the hospitality industry.

Effects of low molecular weight sulfated galactan fragments from Botryocladia occidentalis on the pharmacological and enzymatic activity of sPLA2 from Crotalus durissus cascavella

Low molecular weight fragments of sulfated galactans (Boc-5 and Boc-10) from the red algae Botryocladia occidentalis significantly inhibited Crotalus durissus cascavella sPLA2 enzymatic activity. Equimolar ratios of sPLA2 to Boc-5 or Boc-10 resulted in allosteric inhibition of sPLA2. Under the conditions tested, we observed that both Boc-5 and Boc-10 strongly decreased edema, myonecrosis, and neurotoxicity induced by native sPLA2.

Selenium sulfide in tinea versicolor: blood and urine levels

The safety of topical selenium sulfide lotion in man has been demonstrated previously. Twenty male patients with a diagnosis of tinea versicolor were randomly assigned to two parallel groups who applied selenium sulfide lotion or the vehicle to the entire skin surface, excluding mucous membranes, for 10 minutes once daily for 7 consecutive days. Blood and urine selenium levels were determined before and after treatment and showed no significant differences between the active drug and vehicle groups on any study day. It would appear that no significant absorption of selenium took place as a result of this treatment regimen.

Double-blind efficacy study of selenium sulfide in tinea versicolor

Selenium sulfide (2.5%) lotion applied daily for 10 minutes for 7 consecutive days was found to be an effective therapeutic agent, significantly superior to the vehicle, in a double-blind study in the treatment of tinea versicolor. Mild transitory contact dermatitis of the primary irritant type occurred in all the treatment groups and was apparently due to the detergent base.

Diffuse eosinophilic fasciitis. A new syndrome or variant of Scleroderma?

Recently, attention has been drawn to a scleroderma-like illness, characterized by transient eosinophilia, which is commonly antedated by unusual physical exertion, is apparently free from significant systemic changes, and in which the primary pathological alterations, consisting of intense inflammation and thickening with or without eosinophils, occur initially in the fascia, not the skin. These patients are said to respond well to oral corticosteroids and an occasional one may undergo spontaneous resolution. Clinicopathologic study of a patient with this syndrome, suggests an even deeper tissue genesis than that recently proposed for some of the cutaneoindurative disorders. Eosinophilic fasciitis probably represents an impressive, but perhaps relatively benign variant of diffuse scleroderma, according to reported cases.

Dermatologic manifestations of Schistosomiasis mansoni

Schistosomiasis mansoni, a potentially severe disease that victimizes an appreciable number of US citizens in this hemisphere, shows cutaneous changes corresponding to various stages in the life cycle of the causative parasite within its definitive host. A transient pruritus or dermatitis, probably irritative, characterizes the stage of cercarial penetration. Urticaria, periorbital edema, and rarely a purpuric eruption may occur four to six weeks later, shortly after oviposition by adult worms, probably as an expression of hypersensitivity to ova and their products. Papulonodular lesions, similar to but not as devasting as those developing internally, may rarely appear months later at the perineum or distant cutaneous sites as a manifestation of granulomatous hypersensitivity to eggs and, very rarely, worms, accidentally carried there through collateral and anastomosing vascular pathways.