151 research outputs found

    Circular dichroism spectroscopic detection of ligand binding induced subdomain IB specific structural adjustment of human serum albumin

    Get PDF
    This work demonstrates for the first time that binding of various compounds within subdomain IB of human serum albumin (HSA) provokes characteristic changes in the near-UV circular dichroism (CD) spectrum of the protein. It can be inferred from the spectroscopic features of difference ellipticity signals and from CD displacement experiments that tyrosine residues located in subdomain IB are the source of the observed spectral alterations. It is proposed that inclusion of some ligand molecules (bile acids, dehydroepiandrosterone sulfate, steroidal terpenes, fatty acids, ibuprofen, and gemfibrozil) into the pocket of subdomain IB disrupts the Tyr138?Tyr161 interhelical π?π stacking interaction, which is reflected in the CD spectrum. This phenomenon can be utilized for the CD detection of subdomain IB specific binding of endo- as well as exogenous agents and to study the drug binding associated local conformational adaptation of the HSA molecule

    Cardiometabolic risk profiles in a Sri Lankan twin and singleton sample.

    Get PDF
    INTRODUCTION: Prevention of cardiovascular disease and diabetes is a priority in low- and middle-income countries, especially in South Asia where these are leading causes of morbidity and mortality. The metabolic syndrome is a tool to identify cardiometabolic risk, but the validity of the metabolic syndrome as a clinical construct is debated. This study tested the existence of the metabolic syndrome, explored alternative cardiometabolic risk characterisations, and examined genetic and environmental factors in a South Asian population sample. METHODS: Data came from the Colombo Twin and Singleton follow-up Study, which recruited twins and singletons in Colombo, Sri Lanka, in 2012-2015 (n = 3476). Latent class analysis tested the clustering of metabolic syndrome indicators (waist circumference, high-density lipoprotein cholesterol, triglycerides, blood pressure, fasting plasma glucose, medications, and diabetes). Regression analyses tested cross-sectional associations between the identified latent cardiometabolic classes and sociodemographic covariates and health behaviours. Structural equation modelling estimated genetic and environmental contributions to cardiometabolic risk profiles. All analyses were stratified by sex (n = 1509 men, n = 1967 women). RESULTS: Three classes were identified in men: 1) "Healthy" (52.3%), 2) "Central obesity, high triglycerides, high fasting plasma glucose" (40.2%), and 3) "Central obesity, high triglycerides, diabetes" (7.6%). Four classes were identified in women: 1) "Healthy" (53.2%), 2) "Very high central obesity, low high-density lipoprotein cholesterol, raised fasting plasma glucose" (32.8%), 3) "Very high central obesity, diabetes" (7.2%) and 4) "Central obesity, hypertension, raised fasting plasma glucose" (6.8%). Older age in men and women, and high socioeconomic status in men, was associated with cardiometabolic risk classes, compared to the "Healthy" classes. In men, individual differences in cardiometabolic class membership were due to environmental effects. In women, genetic differences predicted class membership. CONCLUSION: The findings did not support the metabolic syndrome construct. Instead, distinct clinical profiles were identified for men and women, suggesting different aetiological pathways

    Foot-and-Mouth Disease Virus 3C Protease Induces Fragmentation of the Golgi Compartment and Blocks Intra-Golgi Transport

    Get PDF
    Picornavirus infection can cause Golgi fragmentation and impose a block in the secretory pathway which reduces expression of major histocompatibility antigens at the plasma membrane and slows secretion of proinflammatory cytokines. In this study, we show that Golgi fragmentation and a block in secretion are induced by expression of foot-and-mouth disease virus (FMDV) 3C(pro) and that this requires the protease activity of 3C(pro). 3C(pro) caused fragmentation of early, medial, and late Golgi compartments, but the most marked effect was on early Golgi compartments, indicated by redistribution of ERGIC53 and membrin. Golgi fragments were dispersed in the cytoplasm and were able to receive a model membrane protein exported from the endoplasmic reticulum (ER). Golgi fragments were, however, unable to transfer the protein to the plasma membrane, indicating a block in intra-Golgi transport. Golgi fragmentation was coincident with a loss of microtubule organization resulting from an inhibition of microtubule regrowth from the centrosome. Inhibition of microtubule regrowth also required 3C(pro) protease activity. The loss of microtubule organization induced by 3C(pro) caused Golgi fragmentation, but loss of microtubule organization does not block intra-Golgi transport. It is likely that the block of intra-Golgi transport is imposed by separate actions of 3C(pro), possibly through degradation of proteins required for intra-Golgi transport

    Structure of a Murine Norovirus NS6 Protease-Product Complex Revealed by Adventitious Crystallisation

    Get PDF
    Murine noroviruses have emerged as a valuable tool for investigating the molecular basis of infection and pathogenesis of the closely related human noroviruses, which are the major cause of non-bacterial gastroenteritis. The replication of noroviruses relies on the proteolytic processing of a large polyprotein precursor into six non-structural proteins (NS1–2, NS3, NS4, NS5, NS6pro, NS7pol) by the virally-encoded NS6 protease. We report here the crystal structure of MNV NS6pro, which has been determined to a resolution of 1.6 Å. Adventitiously, the crystal contacts are mediated in part by the binding of the C-terminus of NS6pro within the peptide-binding cleft of a neighbouring molecule. This insertion occurs for both molecules in the asymmetric unit of the crystal in a manner that is consistent with physiologically-relevant binding, thereby providing two independent views of a protease-peptide complex. Since the NS6pro C-terminus is formed in vivo by NS6pro processing, these crystal contacts replicate the protease-product complex that is formed immediately following cleavage of the peptide bond at the NS6-NS7 junction. The observed mode of binding of the C-terminal product peptide yields new insights into the structural basis of NS6pro specificity

    The preclinical pharmacology of the high affinity anti-IL-6R Nanobody (R) ALX-0061 supports its clinical development in rheumatoid arthritis

    Get PDF
    Introduction: The pleiotropic cytokine interleukin-6 (IL-6) plays an important role in the pathogenesis of different diseases, including rheumatoid arthritis (RA). ALX-0061 is a bispecific Nanobody (R) with a high affinity and potency for IL-6 receptor (IL-6R), combined with an extended half-life by targeting human serum albumin. We describe here the relevant aspects of its in vitro and in vivo pharmacology. Methods: ALX-0061 is composed of an affinity-matured IL-6R-targeting domain fused to an albumin-binding domain representing a minimized two-domain structure. A panel of different in vitro assays was used to characterize the biological activities of ALX-0061. The pharmacological properties of ALX-0061 were examined in cynomolgus monkeys, using plasma levels of total soluble (s)IL-6R as pharmacodynamic marker. Therapeutic effect was evaluated in a human IL-6-induced acute phase response model in the same species, and in a collagen-induced arthritis (CIA) model in rhesus monkeys, using tocilizumab as positive control. Results: ALX-0061 was designed to confer the desired pharmacological properties. A 200-fold increase of target affinity was obtained through affinity maturation of the parental domain. The high affinity for sIL-6R (0.19 pM) translated to a concentration-dependent and complete neutralization of sIL-6R in vitro. In cynomolgus monkeys, ALX-0061 showed a dose-dependent and complete inhibition of hIL-6-induced inflammatory parameters, including plasma levels of C-reactive protein (CRP), fibrinogen and platelets. An apparent plasma half-life of 6.6 days was observed after a single intravenous administration of 10 mg/kg ALX-0061 in cynomolgus monkeys, similar to the estimated expected half-life of serum albumin. ALX-0061 and tocilizumab demonstrated a marked decrease in serum CRP levels in a non-human primate CIA model. Clinical effect was confirmed in animals with active drug exposure throughout the study duration. Conclusions: ALX-0061 represents a minimized bispecific biotherapeutic of 26 kDa, nearly six times smaller than monoclonal antibodies. High in vitro affinity and potency was demonstrated. Albumin binding as a half-life extension technology resulted in describable and expected pharmacokinetics. Strong IL-6R engagement was shown to translate to in vivo effect in non-human primates, demonstrated via biomarker deregulation as well as clinical effect. Presented results on preclinical pharmacological properties of ALX-0061 are supportive of clinical development in RA

    Antidepressants increase human hippocampal neurogenesis by activating the glucocorticoid receptor

    Get PDF
    Antidepressants increase adult hippocampal neurogenesis in animal models, but the underlying molecular mechanisms are unknown. In this study, we used human hippocampal progenitor cells to investigate the molecular pathways involved in the antidepressant-induced modulation of neurogenesis. Because our previous studies have shown that antidepressants regulate glucocorticoid receptor (GR) function, we specifically tested whether the GR may be involved in the effects of these drugs on neurogenesis. We found that treatment (for 3–10 days) with the antidepressant, sertraline, increased neuronal differentiation via a GR-dependent mechanism. Specifically, sertraline increased both immature, doublecortin (Dcx)-positive neuroblasts (+16%) and mature, microtubulin-associated protein-2 (MAP2)-positive neurons (+26%). This effect was abolished by the GR-antagonist, RU486. Interestingly, progenitor cell proliferation, as investigated by 5′-bromodeoxyuridine (BrdU) incorporation, was only increased when cells were co-treated with sertraline and the GR-agonist, dexamethasone, (+14%) an effect which was also abolished by RU486. Furthermore, the phosphodiesterase type 4 (PDE4)-inhibitor, rolipram, enhanced the effects of sertraline, whereas the protein kinase A (PKA)-inhibitor, H89, suppressed the effects of sertraline. Indeed, sertraline increased GR transactivation, modified GR phosphorylation and increased expression of the GR-regulated cyclin-dependent kinase-2 (CDK2) inhibitors, p27Kip1 and p57Kip2. In conclusion, our data suggest that the antidepressant, sertraline, increases human hippocampal neurogenesis via a GR-dependent mechanism that requires PKA signaling, GR phosphorylation and activation of a specific set of genes. Our data point toward an important role for the GR in the antidepressant-induced modulation of neurogenesis in humans
    • …
    corecore