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Found 37684 matches. Displaying 1841-1850
Zheng FW, Georgescu RE, Li HL, O'Donnell ME
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Structure of eukaryotic DNA polymerase 8 bound to the PCNA clamp while encircling DNA

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2020 DEC 8; 117(48):30344-30353
The DNA polymerase (Pol) 8 of Saccharomyces cerevisiae (S.c.) is composed of the catalytic subunit Pol3 along with two regulatory subunits, Pol31 and Pol32. Pol 8 binds to proliferating cell nuclear antigen (PCNA) and functions in genome replication, repair, and recombination. Unique among DNA polymerases, the Pol3 catalytic subunit contains a 4Fe-4S cluster that may sense the cellular redox state. Here we report the 3.2-angstrom cryo-EM structure of S.c. Pol 8 in complex with primed DNA, an incoming ddTTP, and the PCNA clamp. Unexpectedly, Pol 8 binds only one subunit of the PCNA trimer. This singular yet extensive interaction holds DNA such that the 2-nm-wide DNA threads through the center of the 3-nm interior channel of the clamp without directly contacting the protein. Thus, a water-mediated clamp and DNA interface enables the PCNA clamp to "waterskate" along the duplex with minimum drag. Pol31 and Pol32 are positioned off to the side of the catalytic Pol3-PCNA-DNA axis. We show here that Pol31-Pol32 binds single stranded DNA that we propose underlies polymerase recycling during lagging strand synthesis, in analogy to Escherichia coli replicase. Interestingly, the 4Fe-4S cluster in the C-terminal CysB domain of Pol3 forms the central interface to Pol31-Pol32, and this strategic location may explain the regulation of the oxidation state on Pol 8 activity, possibly useful during cellular oxidative stress. Importantly, human cancer and other disease mutations map to nearly every domain of Pol3, suggesting that all aspects of Pol 8 replication are important to human health and disease.
Eisinger S, Sarhan D, Boura VF, Ibarlucea-Benitez I, Tyystjarvi S, Oliynyk G, Arsenian-Henriksson M, Lane D, Wikstrom SL, Kiessling R, Virgilio T, Gonzalez SF, Kaczynska D, Kanatani S, Daskalaki E, Wheelock CE, Sedimbi S, Chambers BJ, Ravetch JV, Karlsson MCI
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Targeting a scavenger receptor on tumor-associated macrophages activates tumor cell killing by natural killer cells

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2020 DEC 15; 117(50):32005-32016
Tumor-associated macrophages (TAMs) can have protumor properties, including suppressing immune responses, promoting vascularization and, consequently, augmenting tumor progression. To stop TAM-mediated immunosuppression, we use a novel treatment by injecting antibodies specific for scavenger receptor MARCO, which is expressed on a specific subpopulation of TAMs in the tumor. We now report the location of this TAM as well as the pleiotropic mechanism of action of anti-MARCO antibody treatment on tumor progression and further show that this is potentially relevant to humans. Using specific targeting, we observed decreased tumor vascularization, a switch in the metabolic program of MARCO-expressing macrophages, and activation of natural killer (NK) cell killing through TNF-related apoptosis-inducing ligand (TRAIL). This latter activity reverses the effect of melanoma cell-conditioned macrophages in blocking NK activation and synergizes with T cell-directed immunotherapy, such as antibodies to PD-1 or PD-L1, to enhance tumor killing. Our study thus reveals an approach to targeting the immunosuppressive tumor microenvironment with monoclonal antibodies to enhance NK cell activation and NK cell-mediated killing. This can complement existing T cell-directed immunotherapy, providing a promising approach to combinatorial immunotherapy for cancer.
Hatten ME
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Adding cognitive connections to the cerebellum

SCIENCE 2020 DEC 18; 370(6523):1411-1412
Although the cerebellum was first described in the 17th century and its cytoarchitecture was mapped in the early 20th century, our understanding of the role of the cerebellum is rapidly changing. Initially thought to carry out simple motor control, the cerebellum is now considered to function in complex cognitive tasks. On page 1436 of this issue, Kebschull et al. (1) show that the cerebellar nuclei (CN) evolved from amniotes to humans by duplicating “subnuclei” consisting of two classes of excitatory neurons and three classes of inhibitory neurons. The excitatory cell class of the lateral nucleus that projects to the frontal cortex in mice and is affected in developmental disorders such as autism spectrum disorder (ASD) (2, 3) predominates in the greatly expanded human cerebellum. These studies thus provide molecular insights into emerging studies showing a role for the cerebellum in cognitive behaviors, including modulating dopaminergic reward circuits (4), language (5), and social behavior (6, 7).
Freiwald WA
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Gross means Great

PROGRESS IN NEUROBIOLOGY 2020 DEC; 195(?):? Article 101924
Toubiana J, Levy C, Allali S, Jung C, Leruez-Ville M, Varon E, Bajolle F, Ouldali N, Chareyre J, Bechet S, Elbez A, Casanova JL, Chalumeau M, Cohen R, Cohen JF
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Association between SARS-CoV-2 infection and Kawasaki-like multisystem inflammatory syndrome: a retrospective matched case-control study, Paris, France, April to May 2020

EUROSURVEILLANCE 2020 DEC 3; 25(48):?
Talal AH, Sofikitou EM, Jaanimagi U, Zeremski M, Tobin JN, Marianthi M
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A framework for patient-centered telemedicine: Application and lessons learned from vulnerable populations

JOURNAL OF BIOMEDICAL INFORMATICS 2020 DEC; 112(?):? Article 103622
Virtual technologies can facilitate clinical monitoring, clinician-patient interactions, and enhance patient centered approaches to healthcare delivery. Telemedicine, two-way communication between a healthcare provider and a patient not in the same physical location, emphasizes patient preference and convenience by substituting the transportation of patients with information transfer. We present a framework for implementation of a comprehensive, dynamic, patient-centered telemedicine network deployed in 12 opioid treatment programs (OTP) located throughout New York State (NYS). The program aims to effectively manage hepatitis C virus (HCV) infection via telemedicine with co-administration of HCV and substance use medications. We have found that the Sociotechnical System model with emphasis on patient-centered factors provides a framework for telemedicine deployment and implementation to a vulnerable population. The issue of interoperability between the telemedicine platform and the electronic health record (EHR) system as well as clinical information retrieval for medical decision-making are challenges with implementation of a comprehensive, dynamic telemedicine system. Targeting telemedicine to a vulnerable population requires additional consideration of trust in the security and confidentiality of the telemedicine system. Our contribution is the valuable lessons learned from implementing a comprehensive, dynamic, patient-centered telemedicine system among an OTP network throughout NYS as applied to a vulnerable population that can be generalized to other difficult-to-reach populations.
Jove V, Gong ZY, Hol FJH, Zhao ZL, Sorrells TR, Carroll TS, Prakash M, McBride CS, Vosshall LB
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Sensory Discrimination of Blood and Floral Nectar by Aedes aegypti Mosquitoes

NEURON 2020 DEC 23; 108(6):?
Blood-feeding mosquitoes survive by feeding on nectar for metabolic energy but require a blood meal to develop eggs. Aedes aegypti females must accurately discriminate blood and nectar because each meal promotes mutually exclusive feeding programs with distinct sensory appendages, meal sizes, digestive tract targets, and metabolic fates. We investigated the syringe-like blood-feeding appendage, the stylet, and discovered that sexually dimorphic stylet neurons taste blood. Using pan-neuronal calcium imaging, we found that blood is detected by four functionally distinct stylet neuron classes, each tuned to specific blood components associated with diverse taste qualities. Stylet neurons are insensitive to nectar-specific sugars and respond to glucose only in the presence of additional blood components. The distinction between blood and nectar is therefore encoded in specialized neurons at the very first level of sensory detection in mosquitoes. This innate ability to recognize blood is the basis of vector-borne disease transmission to millions of people worldwide.
Freiwald WA
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Social interaction networks in the primate brain

CURRENT OPINION IN NEUROBIOLOGY 2020 DEC; 65(?):49-58
Primate brains have evolved to understand and engage with their social world. Much about the structure of this world can be gleaned from social interactions. Circuits for the analysis of and participation in social interactions have now been mapped. Increased knowledge about their functional specializations and relative spatial locations promises to greatly improve the understanding of the functional organization of the primate social brain. Detailed electrophysiology, as in the case of the face-processing network, of local operations and functional interactions between areas is necessary to uncover neural mechanisms and computation principles of social cognition. New naturalistic behavioral paradigms, behavioral tracking, and new analytical approaches for parallel non-stationary data will be important components toward a neuroscientific theory of primates' interactive minds.
Lafont E, Marciano BE, Mahlaoui N, Neven B, Bustamante J, Rodriguez-Nava V, Rawat A, Unzaga MJ, Fischer A, Blanche S, Lortholary O, Holland SM, Lebeaux D
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Nocardiosis Associated with Primary Immunodeficiencies (Nocar-DIP): an International Retrospective Study and Literature Review

JOURNAL OF CLINICAL IMMUNOLOGY 2020 NOV; 40(8):1144-1155
Purpose Nocardiosis is a life-threatening infectious disease. We aimed at describing nocardiosis in patients with primary immunodeficiency diseases (PID). Methods This international retrospective cohort included patients with PID and nocardiosis diagnosed and/or published from Jan 1, 2000, to Dec 31, 2016. To identify nocardiosis cases, we analyzed PID databases from the French National Reference Center for PID (Paris, France) and the National Institute of Health (NIH, United States of America) and we performed a literature review on PubMed. Results Forty-nine cases of nocardiosis associated with PID were included: median age at diagnosis of nocardiosis was 19 (0-56) years and most cases were observed among chronic granulomatous disease (CGD) patients (87.8%). Median time from symptoms to diagnosis ofNocardiainfection was 20 (2-257) days. Most frequent clinical nocardiosis presentation was pneumonia (86.7%). Twelve-month mortality rate was 4.2%, and 11.9% of patients experienced a possible recurrence of infection. Nocardiosis more frequently led to the diagnosis of PID among non-CGD patients than in CGD patients. Non-CGD patients experienced more cerebral nocardiosis and more disseminated infections, but mortality and recurrence rates were similar. Highest incidences of nocardiosis among PID cohorts were observed among CGD patients (0.0057 and 0.0044 cases/patient-year in the USA and in France, respectively), followed by IL-12p40 deficiency. Conclusions Among 49 cases of nocardiosis associated with PID, most patients had CGD and lung involvement. Both mortality and recurrence rates were low.
Jain SU, Khazaei S, Marchione DM, Lundgren SM, Wang XS, Weinberg DN, Deshmukh S, Juretic N, Lu C, Allis CD, Garcia BA, Jabado N, Lewis PW
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Histone H3.3 G34 mutations promote aberrant PRC2 activity and drive tumor progression

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2020 NOV 3; 117(44):27354-27364
A high percentage of pediatric gliomas and bone tumors reportedly harbor missense mutations at glycine 34 in genes encoding histone variant H3.3. We find that these H3.3 G34 mutations directly alter the enhancer chromatin landscape of mesenchymal stem cells by impeding methylation at lysine 36 on histone H3 (H3K36) by SETD2, but not by the NSD1/2 enzymes. The reduction of H3K36 methylation by G34 mutations promotes an aberrant gain of PRC2-mediated H3K27me2/3 and loss of H3K27ac at active enhancers containing SETD2 activity. This altered histone modification profile promotes a unique gene expression profile that supports enhanced tumor development in vivo. Our findings are mirrored in G34W-containing giant cell tumors of bone where patient-derived stromal cells exhibit gene expression profiles associated with early osteoblastic differentiation. Overall, we demonstrate that H3.3 G34 oncohistones selectively promote PRC2 activity by interfering with SETD2-mediated H3K36 methylation. We propose that PRC2-mediated silencing of enhancers involved in cell differentiation represents a potential mechanism by which H3.3 G34 mutations drive these tumors.