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Found 37769 matches. Displaying 4561-4570
Liu FY, Zhang Z, Csanady L, Gadsby DC, Chen J
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Molecular Structure of the Human CFTR Ion Channel

CELL 2017 MAR 23; 169(1):85-95.e8
The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP- binding cassette (ABC) transporter that uniquely functions as an ion channel. Here, we present a 3.9 angstrom structure of dephosphorylated human CFTR without nucleotides, determined by electron cryomicroscopy (cryo- EM). Close resemblance of this human CFTR structure to zebrafish CFTR under identical conditions reinforces its relevance for understanding CFTR function. The human CFTR structure reveals a previously unresolved helix belonging to the R domain docked inside the intracellular vestibule, precluding channel opening. By analyzing the sigmoid time course of CFTR current activation, we propose that PKA phosphorylation of the R domain is enabled by its infrequent spontaneous disengagement, which also explains residual ATPase and gating activity of dephosphorylated CFTR. Fromcomparison with MRP1, a feature distinguishing CFTR from all other ABC transporters is the helix- loop transition in transmembrane helix 8, which likely forms the structural basis for CFTR's channel function.
Sagner M, McNeil A, Puska P, Auffray C, Price ND, Hood L, Lavie CJ, Han ZG, Chen Z, Brahmachari SK, McEuien BS, Soares MB, Balling R, Epel E, Arena R
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The P4 Health Spectrum - A Predictive, Preventive, Personalized and Participatory Continuum for Promoting Healthspan

PROGRESS IN CARDIOVASCULAR DISEASES 2017 MAR-APR; 59(5):506-521
Chronic diseases (i.e., noncommunicable diseases), mainly cardiovascular disease, cancer, respiratory diseases and type-2-diabetes, are now the leading cause of death, disability and diminished quality of life on the planet. Moreover, these diseases are also a major financial burden worldwide, significantly impacting the economy of many countries. Healthcare systems and medicine have progressively improved upon the ability to address infectious diseases arid react to adverse health events through both surgical-interventions and pharmacology; we have become efficient in delivering reactive care (i.e., initiating interventions once an individual is on the verge of or has actually suffered a negative health event). However, with slowly progressing and often 'silent' chronic diseases now being the main cause of illness, healthcare and medicine must evolve into a proactive system, moving away from a merely reactive approach to care. Minimal interactions among the specialists and limited information to the general practitioner and to the individual receiving care lead to a fragmented health approach, non-concerted prescriptions, a cattered follow-up and a suboptimal cost-effectiveness ratio. A new approach in medicine that is predictive, preventive, personalized and participatory, which we label here as "P4" holds great promise to reduce the burden of chronic diseases by harnessing technology and an increasingly better understanding of environment-biology interactions, evidence-based interventions and the underlying mechanisms of chronic diseases. In this concept paper, we propose a 'P4 Health Continuum' model as a framework to promote and facilitate multi-stakeholder collaboration with an orchestrated common language and an integrated care model to increase the healthspan. (C) 2016 Elsevier Inc. All rights reserved.
Tangye SG, Pillay B, Randall KL, Avery DT, Phan TG, Gray P, Ziegler JB, Smart JM, Peake J, Arkwright PD, Hambleton S, Orange J, Goodnow CC, Uzel G, Casanova JL, Reyes SOL, Freeman AF, Su HC, Ma CS
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Dedicator of cytokinesis 8-deficient CD4(+) T cells are biased to a T(H)2 effector fate at the expense of T(H)1 and T(H)17 cells

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY 2017 MAR; 139(3):933-949
Background: Dedicator of cytokinesis 8 (DOCK8) deficiency is a combined immunodeficiency caused by autosomal recessive loss-of- function mutations in DOCK8. This disorder is characterized by recurrent cutaneous infections, increased serum IgE levels, and severe atopic disease, including food-induced anaphylaxis. However, the contribution of defects in CD4(+) T cells to disease pathogenesis in these patients has not been thoroughly investigated. Objective: We sought to investigate the phenotype and function of DOCK8-deficient CD4(+) T cells to determine (1) intrinsic and extrinsic CD4 1 T-cell defects and (2) how defects account for the clinical features of DOCK8 deficiency. Methods: We performed in-depth analysis of the CD4(+) T-cell compartment of DOCK8-deficient patients. We enumerated subsets of CD4(+) T helper cells and assessed cytokine production and transcription factor expression. Finally, we determined the levels of IgE specific for staple foods and house dust mite allergens in DOCK8-deficient patients and healthy control subjects. Results: DOCK8-deficient memory CD4 1 T cells were biased toward a T(H)2 type, and this was at the expense of T(H)1 and T(H)17 cells. In vitro polarization of DOCK8-deficient naive CD4(+) T cells revealed the TH2 bias and TH17 defect to be T-cell intrinsic. Examination of allergen-specific IgE revealed plasma IgE from DOCK8-deficient patients is directed against staple food antigens but not house dust mites. Conclusion: Investigations into the DOCK8-deficient CD4(+) T cells provided an explanation for some of the clinical features of this disorder: the T(H)2 bias is likely to contribute to atopic disease, whereas defects in T(H)1 and T(H)17 cells compromise antiviral and antifungal immunity, respectively, explaining the infectious susceptibility of DOCK8-deficient patients.
Kang JY
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Structural basis of transcription arrest by coliphage HK022 Nun in an

ELIFE 2017 MAR 20; 6(?):? Article e25478
Coliphage HK022 Nun blocks superinfection by coliphage lambda, by
Milosevic A, Liebmann T, Knudsen M, Schintu N, Svenningsson P, Greengard P
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Cell- and region-specific expression of depression-related protein p11 (S100a10) in the brain

JOURNAL OF COMPARATIVE NEUROLOGY 2017 MAR 1; 525(4):955-975
P11 (S100a10), a member of the S100 family of proteins, has widespread distribution in the vertebrate body, including in the brain, where it has a key role in membrane trafficking, vesicle secretion, and endocytosis. Recently, our laboratory has shown that a constitutive knockout of p11 (p11-KO) in mice results in a depressive-like phenotype. Furthermore, p11 has been implicated in major depressive disorder (MDD) and in the actions of antidepressants. Since depression affects multiple brain regions, and the role of p11 has only been determined in a few of these areas, a detailed analysis of p11 expression in the brain is warranted. Here we demonstrate that, although widespread in the brain, p11 expression is restricted to distinct regions, and specific neuronal and nonneuronal cell types. Furthermore, we provide comprehensive mapping of p11 expression using in situ hybridization, immunocytochemistry, and whole-tissue volume imaging. Overall, expression spans multiple brain regions, structures, and cell types, suggesting a complex role of p11 in depression. J. Comp. Neurol. 525:955-975, 2017. (c) 2016 Wiley Periodicals, Inc.
Timashev LA, Babcock H, Zhuang XW, de Lange T
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The DDR at telomeres lacking intact shelterin does not require substantial chromatin decompaction

GENES & DEVELOPMENT 2017 MAR 15; 31(6):578-589
Telomeres are protected by shelterin, a six-subunit protein complex that represses the DNA damage response (DDR) at chromosome ends. Extensive data suggest that TRF2 in shelterin remodels telomeres into the t-loop structure, thereby hiding telomere ends from double-stranded break repair and ATM signaling, whereas POT1 represses ATR signaling by excluding RPA. An alternative protection mechanism was suggested recently by which shelterin subunits TRF1, TRF2, and TIN2 mediate telomeric chromatin compaction, which was proposed to minimize access of DDR factors. We performed superresolution imaging of telomeres in mouse cells after conditional deletion of TRF1, TRF2, or both, the latter of which results in the complete loss of shelterin. Upon removal of TRF1 or TRF2, we observed only minor changes in the telomere volume in most of our experiments. Upon codeletion of TRF1 and TRF2, the telomere volume increased by varying amounts, but even those samples exhibiting small changes in telomere volume showed DDR at nearly all telomeres. Upon shelterin removal, telomeres underwent 53BP1-dependent clustering, potentially explaining at least in part the apparent increase in telomere volume. Furthermore, chromatin accessibility, as determined by ATAC-seq (assay for transposase-accessible chromatin [ATAC] with high-throughput sequencing), was not substantially altered by shelterin removal. These results suggest that the DDR induced by shelterin removal does not require substantial telomere decompaction.
Takacs CN, Andreo U, Belote RL, Pulupa J, Scull MA, Gleason CE, Rice CM, Simon SM
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Green fluorescent protein-tagged apolipoprotein E: A useful marker for the study of hepatic lipoprotein egress

TRAFFIC 2017 MAR; 18(3):192-204
Apolipoprotein E (ApoE), a component of very-low-density and high-density lipoproteins, participates in many aspects of lipid transport in the bloodstream. Underscoring its important functions, ApoE isoforms have been associated with metabolic and circulatory disease. ApoE is also incorporated into hepatitis C virus (HCV) particles, and promotes their production and infectivity. Live cell imaging analysis of ApoE behavior during secretion from producing cells thus has the potential to reveal important details regarding lipoprotein and HCV particle biogenesis and secretion from cells. However, this approach requires expression of fluorescently tagged ApoE constructs that need to faithfully reproduce known ApoE behaviors. Herein, we evaluate the usefulness of using an ApoE-GFP fusion protein in studying hepatocyte-derived, ApoEcontaining lipoproteins and HCV particles. We show that while ApoE-GFP alone is not sufficient to support infectious HCV production, it nonetheless colocalizes intracellularly and associates with secreted untagged lipoprotein components. Furthermore, its rate of secretion from hepatic cells is indistinguishable from that of untagged ApoE. ApoE-GFP thus represents a useful marker for ApoE-containing hepatic lipoproteins.
Gleicher N, Orvieto R
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Is the hypothesis of preimplantation genetic screening (PGS) still supportable? A review

JOURNAL OF OVARIAN RESEARCH 2017 MAR 27; 10(?):? Article 21
The hypothesis of preimplantation genetic diagnosis (PGS) was first proposed 20 years ago, suggesting that elimination of aneuploid embryos prior to transfer will improve implantation rates of remaining embryos during in vitro fertilization (IVF), increase pregnancy and live birth rates and reduce miscarriages. The aforementioned improved outcome was based on 5 essential assumptions: (i) Most IVF cycles fail because of aneuploid embryos. (ii) Their elimination prior to embryo transfer will improve IVF outcomes. (iii) A single trophectoderm biopsy (TEB) at blastocyst stage is representative of the whole TE. (iv) TE ploidy reliably represents the inner cell mass (ICM). (v) Ploidy does not change (i. e., self-correct) downstream from blastocyst stage. We aim to offer a review of the aforementioned assumptions and challenge the general hypothesis of PGS. We reviewed 455 publications, which as of January 20, 2017 were listed in PubMed under the search phrase < preimplantation genetic screening (PGS) for aneuploidy>. The literature review was performed by both authors who agreed on the final 55 references. Various reports over the last 18 months have raised significant questions not only about the basic clinical utility of PGS but the biological underpinnings of the hypothesis, the technical ability of a single trophectoderm (TE) biopsy to accurately assess an embryo's ploidy, and suggested that PGS actually negatively affects IVF outcomes while not affecting miscarriage rates. Moreover, due to high rates of false positive diagnoses as a consequence of high mosaicism rates in TE, PGS leads to the discarding of large numbers of normal embryos with potential for normal euploid pregnancies if transferred rather than disposed of. We found all 5 basic assumptions underlying the hypothesis of PGS to be unsupported: (i) The association of embryo aneuploidy with IVF failure has to be reevaluated in view how much more common TE mosaicism is than has until recently been appreciated. (ii) Reliable elimination of presumed aneuploid embryos prior to embryo transfer appears unrealistic. (iii) Mathematical models demonstrate that a single TEB cannot provide reliable information about the whole TE. (iv) TE does not reliably reflect the ICM. (v) Embryos, likely, still have strong innate ability to self0-correct downstream from blastocyst stage, with ICM doing so better than TE. The hypothesis of PGS, therefore, no longer appears supportable. With all 5 basic assumptions underlying the hypothesis of PGS demonstrated to have been mistaken, the hypothesis of PGS, itself, appears to be discredited. Clinical use of PGS for the purpose of IVF outcome improvements should, therefore, going forward be restricted to research studies.
Wright MS, Ulrich MR, Fins JJ
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Guardianship and Clinical Research Participation: The Case of Wards with Disorders of Consciousness

KENNEDY INSTITUTE OF ETHICS JOURNAL 2017 MAR; 27(1):43-70
We review relevant federal law about research on human subjects and state laws on guardian authority to determine whether guardians can consent on behalf of their wards to participation in research. The Common Rule is silent on the issue as are most state guardianship laws. Our analysis shows significant variation in guardians' decision-making authority in the states that do regulate wards' participation in research. We consider how the appointment of guardians for patients with disorders of consciousness (DOC) impacts such patients' access to research. We assert that it is important that such persons be permitted to participate in research, so that their conditions and potential medical interventions can be studied, and that those with similar conditions can benefit from the knowledge gained from these studies. We argue that state guardianship laws should be adapted to specifically give guardians the authority to consent to research on behalf of wards who may be able to regain decisional capacity.
Mendoza JL, Schneider WM, Hoffmann HH, Vercauteren K, Jude KM, Xiong AM, Moraga I, Horton TM, Glenn JS, de Jong YP, Rice CM, Garcia KC
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The IFN-lambda-IFN-lambda R1-IL-10R beta Complex Reveals Structural Features Underlying Type III IFN Functional Plasticity

IMMUNITY 2017 MAR 21; 46(3):379-392
Type III interferons (IFN-lambda s) signal through a heterodimeric receptor complex composed of the IFN-lambda R1 subunit, specific for IFN-lambda s, and interleukin-10Rb (IL-10Rb), which is shared by multiple cytokines in the IL-10 superfamily. Low affinity of IL-10Rb for cytokines has impeded efforts aimed at crystallizing cytokine-receptor complexes. Weused yeast surface display to engineer a higher-affinity IFN-lambda variant, H11, which enabled crystallization of the ternary complex. The structure revealed that IL-10Rb uses a network of tyrosine residues as hydrophobic anchor points to engage IL-10 family cytokines that present complementary hydrophobic binding patches, explaining its role as both a cross-reactive but cytokine-specific receptor. H11 elicited increased antiproliferative and antiviral activities in vitro and in vivo. In contrast, engineered higher-affinity type I IFNs did not increase antiviral potency over wild-type type I IFNs. Our findings provide insight into cytokine recognition by the IL-10R family and highlight the plasticity of type III interferon signaling and its therapeutic potential.