259 research outputs found

    Ezrin interacts with the SARS coronavirus spike protein and restrains infection at the entry stage

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    © 2012 Millet et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Entry of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and its envelope fusion with host cell membrane are controlled by a series of complex molecular mechanisms, largely dependent on the viral envelope glycoprotein Spike (S). There are still many unknowns on the implication of cellular factors that regulate the entry process. Methodology/Principal Findings: We performed a yeast two-hybrid screen using as bait the carboxy-terminal endodomain of S, which faces the cytosol during and after opening of the fusion pore at early stages of the virus life cycle. Here we show that the ezrin membrane-actin linker interacts with S endodomain through the F1 lobe of its FERM domain and that both the eight carboxy-terminal amino-acids and a membrane-proximal cysteine cluster of S endodomain are important for this interaction in vitro. Interestingly, we found that ezrin is present at the site of entry of S-pseudotyped lentiviral particles in Vero E6 cells. Targeting ezrin function by small interfering RNA increased S-mediated entry of pseudotyped particles in epithelial cells. Furthermore, deletion of the eight carboxy-terminal amino acids of S enhanced S-pseudotyped particles infection. Expression of the ezrin dominant negative FERM domain enhanced cell susceptibility to infection by SARS-CoV and S pseudotyped particles and potentiated S-dependent membrane fusion. Conclusions/Significance: Ezrin interacts with SARS-CoV S endodomain and limits virus entry and fusion. Our data present a novel mechanism involving a cellular factor in the regulation of S-dependent early events of infection.This work was supported by the Research Grant Council of Hong Kong (RGC#760208)and the RESPARI project of the International Network of Pasteur Institutes

    Acquisition of pneumococci specific effector and regulatory Cd4+ T cells localising within human upper respiratory-tract mucosal lymphoid tissue

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    The upper respiratory tract mucosa is the location for commensal Streptococcus (S.) pneumoniae colonization and therefore represents a major site of contact between host and bacteria. The CD4(+) T cell response to pneumococcus is increasingly recognised as an important mediator of immunity that protects against invasive disease, with data suggesting a critical role for Th17 cells in mucosal clearance. By assessing CD4 T cell proliferative responses we demonstrate age-related sequestration of Th1 and Th17 CD4(+) T cells reactive to pneumococcal protein antigens within mucosal lymphoid tissue. CD25(hi) T cell depletion and utilisation of pneumococcal specific MHCII tetramers revealed the presence of antigen specific Tregs that utilised CTLA-4 and PDL-1 surface molecules to suppress these responses. The balance between mucosal effector and regulatory CD4(+) T cell immunity is likely to be critical to pneumococcal commensalism and the prevention of unwanted pathology associated with carriage. However, if dysregulated, such responses may render the host more susceptible to invasive pneumococcal infection and adversely affect the successful implementation of both polysaccharide-conjugate and novel protein-based pneumococcal vaccines

    Social interaction style of children and adolescents with high-functioning autism spectrum disorder

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    Qualitative differences in social interaction style exist within the autism spectrum. In this study we examined whether these differences are associated with (1) the severity of autistic symptoms and comorbid disruptive behavior problems, (2) the child's psycho-social health, and (3) executive functioning and perspective taking skills. The social interaction style of 156 children and adolescents (6-19 years) with high-functioning autism spectrum disorder (HFASD) was determined with the Wing Subgroups Questionnaire. An active-but-odd social interaction style was positively associated with symptoms of autism, attention deficit and hyperactivity. Furthermore, an active-but-odd social interaction style was negatively associated with children's psycho-social health and positively with executive functioning problems. Social interaction style explains part of the heterogeneity among children with HFASD

    Couple’s Relationship After the Death of a Child: a Systematic Review

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    When a child dies, the parents must address the changes in their relationship as well as the way that these changes affect their individual adjustment. These two perspectives are addressed in this systematic review. Five databases were systematically searched for papers published in English between January 2000 and February 2014. Of the 646 publications, 24 papers met the inclusion criteria. The results suggest that a child’s death can cause cohesive as well as detrimental effects on a couple’s relationship. Variables that may produce differential outcomes for the marital relationship include situational factors, such as the cause and type of death and the child’s age at the time of death; dyad-level factors, such as surviving children, the pre-death characteristics of the relationship, communication and incongruent grieving; and individuallevel factors, such as the family of origin’s processing of trauma, social support, religious affiliation and finding meaning. Aspects such as marital quality and the couple’s interdependence were found to influence each parent’s individual adjustment. Larger, prospective, ethically conducted studies should be implemented to consolidate these findings. Mental health professionals may benefit from a deeper understanding of the risk and protective factors regarding marital adjustment after a child’s death

    The role of pharmacists in developing countries: the current scenario in Pakistan

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    During the past few years, the pharmacy profession has expanded significantly in terms of professional services delivery and now has been recognized as an important profession in the multidisciplinary provision of health care. In contrast to the situation in developed countries, pharmacists in developing countries are still underutilized and their role as health care professionals is not deemed important by either the community or other health care providers. The aim of this paper is to highlight the role of pharmacists in developing countries, particularly in Pakistan. The paper draws on the literature related to the socioeconomic and health status of Pakistan's population, along with background on the pharmacy profession in the country in the context of the current directions of health care

    Cellular Mechanisms Underlying the Laxative Effect of Flavonol Naringenin on Rat Constipation Model

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    BACKGROUND & AIMS: Symptoms of constipation are extremely common, especially in the elderly. The present study aim to identify an efficacious treatment strategy for constipation by evaluating the secretion-promoting and laxative effect of a herbal compound, naringenin, on intestinal epithelial anion secretion and a rat constipation model, respectively. METHODS/PRINCIPAL FINDINGS: In isolated rat colonic crypts, mucosal addition of naringenin (100 microM) elicited a concentration-dependent and sustained increase in the short-circuit current (I(SC)), which could be inhibited in Cl- free solution or by bumetanide and DPC (diphenylamine-2-carboxylic acid), but not by DIDS (4, 4'- diisothiocyanatostilbene-2, 2'-disulfonic acid). Naringenin could increase intracellular cAMP content and PKA activity, consisted with that MDL-12330A (N-(Cis-2-phenyl-cyclopentyl) azacyclotridecan-2-imine-hydrochloride) pretreatment reduced the naringenin-induced I(SC). In addition, significant inhibition of the naringenin-induced I(SC) by quinidine indicated that basolateral K+ channels were involved in maintaining this cAMP-dependent Cl- secretion. Naringenin-evoked whole cell current which exhibited a linear I-V relationship and time-and voltage- independent characteristics was inhibited by DPC, indicating that the cAMP activated Cl- conductance most likely CFTR (cystic fibrosis transmembrane conductance regulator) was involved. In rat constipation model, administration of naringenin restored the level of fecal output, water content and mucus secretion compared to loperamide-administrated group. CONCLUSIONS: Taken together, our data suggest that naringenin could stimulate Cl- secretion in colonic epithelium via a signaling pathway involving cAMP and PKA, hence provide an osmotic force for subsequent colonic fluid secretion by which the laxative effect observed in the rat constipation model. Naringenin appears to be a novel alternative treatment strategy for constipation

    Uncoupling Protein-4 (UCP4) Increases ATP Supply by Interacting with Mitochondrial Complex II in Neuroblastoma Cells

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    Mitochondrial uncoupling protein-4 (UCP4) protects against Complex I deficiency as induced by 1-methyl-4-phenylpyridinium (MPP+), but how UCP4 affects mitochondrial function is unclear. Here we investigated how UCP4 affects mitochondrial bioenergetics in SH-SY5Y cells. Cells stably overexpressing UCP4 exhibited higher oxygen consumption (10.1%, p<0.01), with 20% greater proton leak than vector controls (p<0.01). Increased ATP supply was observed in UCP4-overexpressing cells compared to controls (p<0.05). Although state 4 and state 3 respiration rates of UCP4-overexpressing and control cells were similar, Complex II activity in UCP4-overexpressing cells was 30% higher (p<0.05), associated with protein binding between UCP4 and Complex II, but not that of either Complex I or IV. Mitochondrial ADP consumption by succinate-induced respiration was 26% higher in UCP4-overexpressing cells, with 20% higher ADP:O ratio (p<0.05). ADP/ATP exchange rate was not altered by UCP4 overexpression, as shown by unchanged mitochondrial ADP uptake activity. UCP4 overexpression retained normal mitochondrial morphology in situ, with similar mitochondrial membrane potential compared to controls. Our findings elucidate how UCP4 overexpression increases ATP synthesis by specifically interacting with Complex II. This highlights a unique role of UCP4 as a potential regulatory target to modulate mitochondrial Complex II and ATP output in preserving existing neurons against energy crisis

    Escitalopram and Neuroendocrine Response in Healthy First-Degree Relatives to Depressed Patients – A Randomized Placebo-Controlled Trial

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    INTRODUCTION: The mechanisms by which selective serotonin re-uptake inhibitors (SSRI) act in depressed patients remain unknown. The serotonergic neurotransmitter system and the hypothalamic-pituitary-adrenal (HPA) system may interact. The aim of the AGENDA trial was to investigate whether long-term intervention with SSRI versus placebo affects the cortisol response in the dexamethasone corticotropin-releasing hormone (DEX-CRH) test in healthy first-degree relatives to patients with major depressive disorder (MDD). METHODS: Eighty healthy first-degree relatives to patients with MDD were randomized to escitalopram 10 mg versus matching placebo daily for four weeks. The primary outcome measure was the intervention difference in the change of the total area under the curve (CorAUC(total)) for plasma cortisol in the DEX-CRH test at entry to after four weeks of intervention. RESULTS: Change in CorAUC(total) showed no statistically significant difference between the escitalopram and the placebo group, p = 0.47. There were large intra- and inter-individual differences in the results of the DEX-CRH test. There was statistically significant negative correlation between the plasma escitalopram concentration and change in CorAUC(total), rho = -0.41, p = 0.01. Post-hoc analyses showed a statistically significant interaction between age and intervention group and change in log CorAUC(total). CONCLUSION: The present trial does not support an effect of escitalopram 10 mg daily compared with placebo on the HPA-axis in healthy first-degree relatives to patients with MDD. Increasing levels of escitalopram tended to decrease the HPA-response in the DEX-CRH test and this effect increased with age. TRIAL REGISTRATION: ClinicalTrials.gov NCT00386841
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