Interaction between obesity-related genes, FTO and MC4R, associated to an increase of breast cancer risk

Breast cancer (BC) is a complex disease and obesity is a well-known risk factor for its development, especially after menopause. Several studies have shown Single Nucleotide Polymorphisms (SNPs) linked to overweight and obesity, such as: rs1121980 (T/C) and rs9939609 (A/T) in Fat Mass and Obesity Associated gene (FTO) and rs17782313 (T/C) in Melanocortin 4 Receptor gene (MC4R). Thus, we aimed to investigate the association between these obesity-related SNPs and BC risk. One hundred BC patients and 148 healthy women from Santa Catarina, Brazil entered the study. SNPs were genotyped using Taqman assays. For statistical analyses SNPStats and SPSS softwares were used. Association analyses were performed by logistic regression and were adjusted for age and Body mass index (BMI). Multiple SNPs inheritance models (log-additive, dominant, recessive, codominant) were performed to determine odds ratios (ORs), assuming 95 % confidence interval (CI) and P value = 0.05 as the significance limit. When analyzed alone, FTO rs1121980 and rs9939609 did not show significant associations with BC development, however MC4R rs17782313 showed increased risk for BC even after adjustments (P-value = 0.032). Interestingly, the interaction of FTO and MC4R polymorphisms showed a powerful association with BC. We observed a 4.59-fold increased risk for woman who have the allele combination C/T/C (FTO rs1121980/FTO rs9939609/MC4R rs17782313) (P-value = 0.0011, adjusted for age and BMI). We found important and unpublished associations between these obesity-related genes and BC risk. These associations seem to be independent of their effect on BMI, indicating a direct role of the interaction between FTO and MC4R polymorphisms in BC development.     

Tricellulin expression in brain endothelial and neural cells

Tricellulin is a tight junction (TJ) protein, which is not only concentrated at tricellular contacts but also present at bicellular contacts between epithelial tissues. We scrutinized the brain for tricellulin expression in endothelial and neural cells by using real-time polymerase chain reaction, Western blot and immunohistochemical and immunocytochemical analysis of cultured brain cells and paraffin sections of brain. Tricellulin mRNA was detected in primary cultures and in a cell line of human brain microvascular endothelial cells. Protein expression was confirmed by Western blot and immunofluorescence analysis, which further highlighted the localization of tricellulin in the cell membrane at tricellular and along bicellular contacts, and in the nucleus and perinuclear region. Compared with the well-studied TJ protein, zonula occludens-1, tricellulin expression was less marked at the cell membrane but more evident in the nuclear and perinuclear regions. The presence of tricellulin in cultured endothelial cells was corroborated by immunohistochemical and immunofluorescence staining in brain blood vessels, where it was colocalized with another TJ protein, claudin-5. Tricellulin mRNA was detected in neurons and astrocytes, whereas protein expression was observed in astrocytes but not in neurons, as shown by immunofluorescence analysis. This study reveals the presence and subcellular distribution of tricellulin in brain endothelial cells, both in vitro and in situ and its colocalization with other relevant TJ proteins. Moreover, it demonstrates the expression of the protein in astrocytes opening new avenues for future research to establish the biological significance of tricellulin expression in glial cells.     

Cross-Talk Between Neurons and Astrocytes in Response to Bilirubin: Early Beneficial Effects

Hyperbilirubinemia remains one of the most frequent clinical diagnoses in the neonatal period. This condition may lead to the deposition of unconjugated bilirubin (UCB) in the central nervous system, causing nerve cell damage by molecular and cellular mechanisms that are still being clarified. To date, all the studies regarding bilirubin-induced neurological dysfunction were performed in monotypic nerve cell cultures. The use of co-cultures, where astrocyte-containing culture inserts are placed on the top of neuron cultures, provides the means to directly evaluate the cross-talk between these two different cell types. Therefore, this study was designed to evaluate whether protective or detrimental effects are produced by astrocytes over UCB-induced neurodegeneration. Our experimental model used an indirect co-culture system where neuron-to-astrocyte signaling was established concomitantly with the 24 h exposure to UCB. In this model astrocytes abrogated the well-known UCB-induced neurotoxic effects by preventing the loss of cell viability, dysfunction and death by apoptosis, as well as the impairment of neuritic outgrowth. To this protection it may have accounted the induced expression of the multidrug resistance-associated protein 1 and the 3.5-fold increase in the values of S100B, when communication between both cells was established independently of UCB presence. In addition, the presence of astrocytes in the neuronal environment preserved the UCB-induced increase in glutamate levels, but raised the basal concentrations of nitric oxide and TNF-α although no UCB effects were noticed. Our data suggest that bidirectional signalling during astrocyte-neuron recognition exerts pro-survival effects, stimulates neuritogenesis and sustains neuronal homeostasis, thus protecting cells from the immediate UCB injury. These findings may help explain why irreversible brain damage usually develops only after the first day of post-natal life.     

Rope trauma,sedation, disentanglement,and monitoring‐tag associated lesions in a terminally entangled North Atlantic right whale (Eubalaena glacialis)

A chronically entangled North Atlantic right whale, with consequent emaciation was sedated, disentangled to the extent possible, administered antibiotics, and satellite tag tracked for six subsequent days. It was found dead 11 d after the tag ceased transmission. Chronic constrictive deep rope lacerations and emaciation were found to be the proximate cause of death, which may have ultimately involved shark predation. A broadhead cutter and a spring‐loaded knife used for disentanglement were found to induce moderate wounds to the skin and blubber. The telemetry tag, with two barbed shafts partially penetrating the blubber was shed, leaving barbs embedded with localized histological reaction. One of four darts administered shed the barrel, but the needle was found postmortem in the whale with an 80º bend at the blubber‐muscle interface. This bend occurred due to epaxial muscle movement relative to the overlying blubber, with resultant necrosis and cavitation of underlying muscle. This suggests that rigid, implanted devices that span the cetacean blubber muscle interface, where the muscle moves relative to the blubber, could have secondary health impacts. Thus we encourage efforts to develop new tag telemetry systems that do not penetrate the subdermal sheath, but still remain attached for many months.     

Biomembrane simulations of 12 lipid types using the general amber force field in a tensionless ensemble

The AMBER family of force fields is one of the most commonly used alternatives to describe proteins and drug-like molecules in molecular dynamics simulations. However, the absence of a specific set of parameters for lipids has been limiting the widespread application of this force field in biomembrane simulations, including membrane protein simulations and drug-membrane simulations. Here, we report the systematic parameterization of 12 common lipid types consistent with the General Amber Force Field (GAFF), with charge-parameters determined with RESP at the HF/6–31G(d) level of theory, to be consistent with AMBER. The accuracy of the scheme was evaluated by comparing predicted and experimental values for structural lipid properties in MD simulations in an NPT ensemble with explicit solvent in 100:100 bilayer systems. Globally, a consistent agreement with experimental reference data on membrane structures was achieved for some lipid types when using the typical MD conditions normally employed when handling membrane proteins and drug-membrane simulations (a tensionless NPT ensemble, 310?K), without the application of any of the constraints often used in other biomembrane simulations (such as the surface tension and the total simulation box area). The present set of parameters and the universal approach used in the parameterization of all the lipid types described here, as well as the consistency with the AMBER force field family, together with the tensionless NPT ensemble used, opens the door to systematic studies combining lipid components with small drug-like molecules or membrane proteins and show the potential of GAFF in dealing with biomembranes.     

Evidence of tricellulin expression by immune cells, particularly microglia

Tight junctions (TJs) are elaborate structures located on the apical region of epithelial cells that limit paracellular permeability. Tricellulin is a recently discovered TJ protein, which is concentrated at the structurally specialized tricellular TJs but also present at bicellular contacts between epithelial cells, namely in the stomach. Interestingly, several TJ proteins have been found in other than epithelial cells, as astrocytes, and tricellulin mRNA expression was reported in mature dendritic cells. These findings prompted us to look for tricellulin expression in both epithelial and immune cells in the stomach, as well as in microglia, the brain resident immunocompetent cells. Immunohistochemical analysis of human stomach tissue sections revealed peroxidase staining at three-corner contact sites, as well as at the contact between two adjacent epithelial cells, thus evidencing the expression of tricellulin not only at tricellullar but at bicellular junctions as well. Such analysis, further revealed tricellulin immunostaining in cells of the monocyte/macrophage lineage, scattered throughout the lamina propria. Cultured rat microglia exhibited a notorious tricellulin staining, consistent with an extensive expression of the protein along the cell, which was not absolutely coincident with the lysosomal marker CD68. Detection of mRNA expression by real-time PCR provided supportive evidence for the expression of the TJ protein in microglia. These data demonstrate for the first time that microglia express a TJ protein. Moreover, the expression of tricellulin both in microglia and in the stomach immune cells point to a possible role of this new TJ protein in the immune system.     

Induced responses of Coffea arabica to attack of Coccus viridis stimulate locomotion of the herbivore

The green scale, Coccus viridis (Green) (Hemiptera: Coccidae), is an insect pest of coffee and several other perennial cultivated plant species. We investigated changes in alkaloid and phenolic contents in coffee plants as a response to herbivory by this insect. Greenhouse‐grown, 11‐month‐old coffee plants were artificially infested with the coccid and compared with control, uninfested plants. Leaf samples were taken at 15, 30, 45, and 60 days after infestation, and high‐performance liquid chromatography was used to identify and quantify alkaloid and phenolic compounds induced by the coccids at each sampling date. Of the compounds investigated, caffeine was the main coffee alkaloid detected in fully developed leaves, and its concentration in infested plants was twice as high as in the control plants. The main coffee phenolics were caffeic and chlorogenic acid, and a significant increase in their concentrations occurred only in plants infested by C. viridis. A positive and significant relationship was found between alkaloid and phenolic concentrations and the infestation level by adults and nymphs of C. viridis. Caffeine and chlorogenic acid applied on coffee leaves stimulated the locomotory activity of the green scale, thus reducing their feeding compared to untreated leaves. This is the first study to show increased levels of coffee alkaloids and phenolics in response to herbivory by scale insects. The elevation of caffeine and chlorogenic acid levels in coffee leaves because of C. viridis infestation seems to affect this generalist insect by stimulating the locomotion of crawlers.