Exosomes from bronchoalveolar fluid of tolerized mice prevent allergic reaction

Exosomes are nanovesicles originating from multivesicular bodies that are secreted by a variety of cell types. The dual capability of exosomes to promote immunity or to induce tolerance has prompted their clinical use as vehicles for vaccination against different human diseases. In the present study, the effect of allergen-specific exosomes from tolerized mice on the development of allergen-induced allergic response was determined using a mouse model. Mice were tolerized by respiratory exposure to the olive pollen allergen Ole e 1. Exosome-like vesicles were isolated from bronchoalveolar lavage fluid of the animals by the well-established filtration and ultracentrifugation procedure, characterized by electron microscopy, Western blot, and FACS analyses, and assessed in a prophylactic protocol. To this end, BALB/c mice were intranasally treated with tolerogenic exosomes or naive exosomes as control, 1 wk before sensitization/challenge to Ole e 1. Blood, lungs, and spleen were collected and analyzed for immune responses. Intranasal administration of tolerogenic exosomes inhibited the development of IgE response, Th2 cytokine production, and airway inflammation--cardinal features of allergy--and maintained specific long-term protection in vivo. This protective effect was associated with a concomitant increase in the expression of the regulatory cytokine TGF-beta. These observations demonstrate that exosomes can induce tolerance and protection against allergic sensitization in mice. Thus, exosome-based vaccines could represent an alternative to conventional therapy for allergic diseases in humans.     

Quantitative determination of the topological propensities of amyloidogenic peptides

One of the interesting puzzles of amyloid beta-peptide of Alzheimer's disease (Abeta) is that it appears to polymerize into amyloid fibrils in a parallel beta sheet topology, while smaller subsets of the peptide produce anti-parallel beta sheets. In order to target potential weak points of amyloid fibrils in a rational drug design effort, it would be helpful to understand the forces that drive this change. We have designed two peptides CHQKLVFFAEDYNGKDEAFFVLKQHW and CHQKLVFFAEDYNGKHQKLVFFAEDW that join the significant amyloidogenic Abeta (14-23) sequence HQKLVFFAED in parallel and anti-parallel topologies, respectively. (Here, the word "parallel" refers only to residue sequence and not backbone topology). The N-termini of the hairpins were labeled with the fluorescent dye 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid (IAEDANS), forming a fluorescence energy transfer donor-acceptor pair with the C-terminus tryptophan. Circular dichroism results show that the anti-parallel hairpin adopts a beta-sheet conformation, while the parallel hairpin is disordered. Fluorescent Resonance Energy Transfer (FRET) results show that the distance between the donor and the acceptor is significantly shorter in the anti-parallel topology than in the parallel topology. The fluorescence intensity of anti-parallel hairpin also displays a linear concentration dependence, indicating that the FRET observed in the anti-parallel hairpin is from intra-molecular interactions. The results thus provide a quantitative estimate of the relative topological propensities of amyloidogenic peptides. Our FRET and CD results show that beta sheets involving the essential Abeta (14-23) fragment, strongly prefer the anti-parallel topology. Moreover, we provide a quantitative estimate of the relative preference for these two topologies. Such analysis can be repeated for larger subsets of Abeta to determine quantitatively the relative degree of preference for parallel/anti-parallel topologies in given fragments of Abeta.     

Immunoproteomic analysis of the protective response obtained from vaccination with Candida albicans ecm33 cell wall mutant in mice

Systemic candidiasis remains a major cause of disease and death, particularly among immunocompromised patients. The cell wall of Candida albicans defines the interface between host and pathogen and surface proteins are major elicitors of host immune responses during candidiasis. The C. albicans ecm33 mutant (RML2U) presents an altered cell wall, which entails an increase in the outermost protein layer. Vaccination of BALB/c mice with RML2U mutant protected them from a subsequent lethal infection with virulent strain SC5314 in a systemic candidiasis model. Using immunoproteomics (2-DE followed by Immunoblotting) we detected 29 immunoreactive proteins specifically recognized by antibodies from vaccinated mice sera, six of which are described as immunogenic for the first time (Gnd1p, Cit1p, Rpl10Ep, Yst1p, Cys4p, Efb1p). Furthermore, identification of wild type and mutant cell surface proteome (surfome), confirmed us that the mutant surfome presented a larger number of proteins than the wild type. Interestingly, proteins exclusively identified in the mutant surfome (Met6p, Eft2p, Tkl1p, Rpl10Ep, Atp1p, Atp2p) were also detected as immunogenic, supporting the idea that their surface location enhances their immunoprotective capacity.     

Phylogenetic and biochemical characterisation of a recombinant laccase from Trametes versicolor

Laccases are important enzymes for bioremediation and the best-characterised are from the fungus Trametes versicolor. Here, we describe the cloning and characterisation of a new variant of laccase from T. versicolor and its expression in Saccharomyces cerevisiae. We have performed a sequence-based analysis of Trametes laccases that leads to a proposal for a new nomenclature of this fungus laccases according to their phylogenetic relationships since their nomenclature based on IPs is ambiguous. We also describe the kinetic properties of the recombinant enzyme.     

Adiponectin is synthesized and secreted by human and murine cardiomyocytes

Adiponectin is thought to play a decisive role in the relationships among obesity, insulin resistance and cardiovascular risk. This study investigated whether cardiomyocytes synthesize and secrete adiponectin, and the effects of this hormone on cardiac cells. RT-PCR showed that mouse, rat and human cardiomyocytes produced mRNA for adiponectin and adiponectin receptors 1 and 2. Immunohistochemistry confirmed the presence of adiponectin in the cytoplasm of cultured cardiomyocytes, and radioimmunoassay showed that these cells secreted adiponectin into the culture medium. Exogenous adiponectin enhanced glucose and fatty acid uptake and induced AMPK phosphorylation in cultured cardiomyocytes. Our results demonstrate that adiponectin is synthesized and secreted by isolated murine and human cardiomyocytes, and suggest that the local production of this hormone by cardiomyocytes could be involved in the regulation of cardiac metabolism and function.     

Lactose derivatives are inhibitors of Trypanosoma cruzi trans-sialidase activity toward conventional substrates in vitro and in vivo

Chagas' disease, caused by Trypanosoma cruzi, affects about 18 million people in Latin America, and no effective treatment is available to date. To acquire sialic acid from the host glycoconjugates, T. cruzi expresses an unusual surface sialidase with trans-sialidase activity (TcTS) that transfers the sugar to parasite mucins. Surface sialic acid was shown to have relevant functions in protection of the parasite against the lysis by complement and in mammalian host cell invasion. The recently determined 3D structure of TcTS allowed a detailed analysis of its catalytic site and showed the presence of a lactose-binding site where the beta-linked galactose accepting the sialic acid is placed. In this article, the acceptor substrate specificity of lactose derivatives was studied by high pH anion-exchange chromatography with pulse amperometric detection. The lactose open chain derivatives lactitol and lactobionic acid, as well as other derivatives, were found to be good acceptors of sialic acid. Lactitol, which was the best of the ones tested, effectively inhibited the transfer of sialic acid to N-acetyllactosamine. Furthermore, lactitol inhibited parasite mucins re-sialylation when incubated with live trypanosomes and TcTS. Lactitol also diminished the T. cruzi infection in cultured Vero cells by 20-27%. These results indicate that compounds directed to the lactose binding site might be good inhibitors of TcTS.     

It Weigh(t)s on You: Everyday Discrimination and Adiposity Among Latinos

Objective

Evidence suggests discrimination increases the risk of obesity. The biopsychosocial model of racism posits that psychological factors such as depressive symptoms may link experiences of perceived interpersonal discrimination to obesity. This study tested whether self‐reported experiences of everyday discrimination were associated with adiposity indicators and whether depressive symptoms explained these associations.

Methods

Cross‐sectional survey data of 602 Latino adults living in Lawrence, Massachusetts, from the Latino Health and Well‐being Project (2011‐2013) were used. Participants completed questionnaires assessing perceived everyday discrimination and depressive symptoms. Anthropometric measures (i.e., BMI and waist circumference [WC]) were obtained by trained staff. Structural equation modeling was employed to test for direct and indirect effects of perceived everyday discrimination on adiposity.

Results

Perceived everyday discrimination was directly and positively associated with higher BMI and WC, independent of sociodemographic factors, physical activity, and stressful life events. Perceived everyday discrimination was not indirectly associated with BMI and WC through depressive symptoms. However, perceived everyday discrimination was associated with higher levels of depressive symptoms.

Conclusions

Self‐reported everyday discrimination among Latino adults is associated with adiposity. Day‐to‐day interpersonal discrimination may be implicated in obesity disparities for Latino adults.

     

The Oldest Beetle and Bee Ichnofossils from Mexico and their Paleoenvironmental Implications

ABSTRACT

Specimens of Fictovichnus gobiensis, Celliforma curvata, Celliforma rosellii, Celliforma germanica and Celliforma isp. were collected from paleosol horizons in a fluviolacustrine succession near Santiago Yolomécatl town, in northwestern Oaxaca, southern Mexico. These ichnofossils represent the oldest evidence of beetles and bees in Mexican localities. K–Ar ages and the record of the equid Miohippus assiniboiensis, an index fossil, indicate that the age of the deposits is late Eocene. Based on the presence of the insect ichnofossils, pedogenic carbonate isotopes and mammal proxies, the inferred type of vegetation present in the study area was scrubland/woodland, within subhumid to subarid conditions.     

Prognostic and Predictive Significance of MYC and KRAS Alterations in Breast Cancer from Women Treated with Neoadjuvant Chemotherapy

Breast cancer is a complex disease, with heterogeneous clinical evolution. Several analyses have been performed to identify the risk factors for breast cancer progression and the patients who respond best to a specific treatment. We aimed to evaluate whether the hormone receptor expression, HER2 and MYC genes and their protein status, and KRAS codon 12 mutations may be prognostic or predictive biomarkers of breast cancer. Protein, gene and mutation status were concomitantly evaluated in 116 breast tumors from women who underwent neoadjuvant chemotherapy with doxorubicin plus cyclophosphamide. We observed that MYC expression was associated with luminal B and HER2 overexpression phenotypes compared to luminal A (p<0.05). The presence of MYC duplication or polysomy 8, as well as KRAS mutation, were also associated with the HER2 overexpression subtype (p<0.05). MYC expression and MYC gain were more frequently observed in early-onset compared to late-onset tumors (p<0.05). KRAS mutation was a risk factor of grade 3 tumors (p<0.05). A multivariate logistic regression demonstrated that MYC amplification defined as MYC/nucleus ratio of ≥2.5 was a protective factor for chemotherapy resistance. On the other hand, age and grade 2 tumors were a risk factor. Additionally, luminal B, HER2 overexpression, and triple-negative tumors presented increased odds of being resistant to chemotherapy relative to luminal A tumors. Thus, breast tumors with KRAS codon 12 mutations seem to present a worse prognosis. Additionally, MYC amplification may help in the identification of tumors that are sensitive to doxorubicin plus cyclophosphamide treatment. If confirmed in a large set of samples, these markers may be useful for clinical stratification and prognosis.