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Found 37684 matches. Displaying 1991-2000
Zou CH, Vercauteren KOA, Michailidis E, Kabbani M, Zoluthkin I, Quirk C, Chiriboga L, Yazicioglu M, Anguela XM, Meuleman P, High KA, Herzog RW, de Jong YP
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Experimental Variables that Affect Human Hepatocyte MV Transduction in Liver Chimeric Mice

MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020 SEP 11; 18(?):189-198
Adeno-associated virus (AAV) vector serotypes vary in their ability to transduce hepatocytes from different species. Chimeric mouse models harboring human hepatocytes have shown translational promise for liver-directed gene therapies. However, many variables that influence human hepatocyte transduction and transgene expression in such models remain poorly defined. Here, we aimed to test whether three experimental conditions influence AAV transgene expression in immunodeficient, fumaryl-acetoactetate-hydrolase-deficient (Fah(-/-)) chimeric mice repopulated with primary human hepatocytes. We examined the effects of the murine liver injury cycle, human donor variability, and vector doses on hepatocyte transduction with various AAV serotypes expressing a green fluorescent protein (GFP). We determined that the timing of AAV vector challenge in the liver injury cycle resulted in up to 7-fold differences in the percentage of GFP expressing human hepatocytes. The GFP+ hepatocyte frequency varied 7-fold between human donors without, however, changing the relative transduction efficiency between serotypes for an individual donor. There was also a clear relationship between AAV vector doses and human hepatocyte transduction and transgene expression. We conclude that several experimental variables substantially affect human hepatocyte transduction in the Fah(-/-) chimera model, attention to which may improve reproducibility between findings from different laboratories.
Fiore VF, Krajnc M, Quiroz FG, Levorse J, Pasolli HA, Shvartsman SY, Fuchs E
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Mechanics of a multilayer epithelium instruct tumour architecture and function

NATURE 2020 SEP 17; 585(7825):433-439
Mathematical and experimental approaches are used to investigate the mechanical forces that shape the tumour architecture of two different common forms of skin cancer: basal cell carcinomas and invasive squamous cell carcinomas. Loss of normal tissue architecture is a hallmark of oncogenic transformation(1). In developing organisms, tissues architectures are sculpted by mechanical forces during morphogenesis(2). However, the origins and consequences of tissue architecture during tumorigenesis remain elusive. In skin, premalignant basal cell carcinomas form 'buds', while invasive squamous cell carcinomas initiate as 'folds'. Here, using computational modelling, genetic manipulations and biophysical measurements, we identify the biophysical underpinnings and biological consequences of these tumour architectures. Cell proliferation and actomyosin contractility dominate tissue architectures in monolayer, but not multilayer, epithelia. In stratified epidermis, meanwhile, softening and enhanced remodelling of the basement membrane promote tumour budding, while stiffening of the basement membrane promotes folding. Additional key forces stem from the stratification and differentiation of progenitor cells. Tumour-specific suprabasal stiffness gradients are generated as oncogenic lesions progress towards malignancy, which we computationally predict will alter extensile tensions on the tumour basement membrane. The pathophysiologic ramifications of this prediction are profound. Genetically decreasing the stiffness of basement membranes increases membrane tensions in silico and potentiates the progression of invasive squamous cell carcinomas in vivo. Our findings suggest that mechanical forces-exerted from above and below progenitors of multilayered epithelia-function to shape premalignant tumour architectures and influence tumour progression.
Wong JJM, Ginter PS, Tyryshkin K, Yang XJ, Nanayakkara J, Zhou ZE, Tuschl T, Chen YT, Renwick N
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Classifying Lung Neuroendocrine Neoplasms through MicroRNA Sequence Data Mining

CANCERS 2020 SEP; 12(9):? Article 2653
Simple Summary Lung neuroendocrine neoplasms (NENs) are a subset of lung cancer that is difficult to diagnose. MicroRNAs (miRNAs) are small RNA molecules that are valuable markers in many cancers. In this study, we generated miRNA profiles for 55 preserved lung NEN samples (14 typical carcinoid (TC), 15 atypical carcinoid (AC), 11 small cell lung carcinoma (SCLC), and 15 large cell neuroendocrine carcinoma (LCNEC)), and randomly assigned them to either discovery or validation sets. We used machine learning and data mining algorithms to identify important miRNA that can distinguish between the types. Using the miRNAs identified with these algorithms, we were able to distinguish between carcinoids (TC and AC) and neuroendocrine carcinomas (SCLC and LCNEC) in the discovery set with 93% accuracy; in the validation set, we were able to distinguish between these groups with 100% accuracy. Using the same machine learning and data mining techniques, we also identified miRNAs that can distinguish between TC and AC, and SCLC and LCNEC, however more samples are needed to validate these findings. Lung neuroendocrine neoplasms (NENs) can be challenging to classify due to subtle histologic differences between pathological types. MicroRNAs (miRNAs) are small RNA molecules that are valuable markers in many neoplastic diseases. To evaluate miRNAs as classificatory markers for lung NENs, we generated comprehensive miRNA expression profiles from 14 typical carcinoid (TC), 15 atypical carcinoid (AC), 11 small cell lung carcinoma (SCLC), and 15 large cell neuroendocrine carcinoma (LCNEC) samples, through barcoded small RNA sequencing. Following sequence annotation and data preprocessing, we randomly assigned these profiles to discovery and validation sets. Through high expression analyses, we found that miR-21 and -375 are abundant in all lung NENs, and that miR-21/miR-375 expression ratios are significantly lower in carcinoids (TC and AC) than in neuroendocrine carcinomas (NECs; SCLC and LCNEC). Subsequently, we ranked and selected miRNAs for use in miRNA-based classification, to discriminate carcinoids from NECs. Using miR-18a and -155 expression, our classifier discriminated these groups in discovery and validation sets, with 93% and 100% accuracy. We also identified miR-17, -103, and -127, and miR-301a, -106b, and -25, as candidate markers for discriminating TC from AC, and SCLC from LCNEC, respectively. However, these promising findings require external validation due to sample size.
Saeed M, Kapell S, Hertz NT, Wu XF, Bell K, Ashbrook AW, Mark MT, Zebroski HA, Neal ML, Flodstrom-Tullberg M, MacDonald MR, Aitchison JD, Molina H, Rice CM
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Defining the proteolytic landscape during enterovirus infection

PLOS PATHOGENS 2020 SEP; 16(9):? Article e1008927
Viruses cleave cellular proteins to remodel the host proteome. The study of these cleavages has revealed mechanisms of immune evasion, resource exploitation, and pathogenesis. However, the full extent of virus-induced proteolysis in infected cells is unknown, mainly because until recently the technology for a global view of proteolysis within cells was lacking. Here, we report the first comprehensive catalog of proteins cleaved upon enterovirus infection and identify the sites within proteins where the cleavages occur. We employed multiple strategies to confirm protein cleavages and assigned them to one of the two enteroviral proteases. Detailed characterization of one substrate, LSM14A, a p body protein with a role in antiviral immunity, showed that cleavage of this protein disrupts its antiviral function. This study yields a new depth of information about the host interface with a group of viruses that are both important biological tools and significant agents of disease. Author summary Enteroviruses are associated with a variety of human diseases, including gastroenteritis, the common cold, hand-foot-and-mouth disease, acute hemorrhagic conjunctivitis, and skin rash. In some cases, the infection can lead to myocarditis, encephalitis, progressive muscle weakness, and paralysis. Exactly how enteroviruses invade human tissues, defeat the host immune system, and alter normal cell biology is unknown. Understanding these cellular and molecular mechanisms will blaze the trail for the development of novel vaccine and therapeutic strategies. Here, we have applied a global N-terminomics approach to investigate how various enteroviruses recruit their proteases to remodel an infected cell, disarm host immunity, and create a favorable environment for their replication. This effort identified several new protease substrates, which we then confirmed by other experimental approaches. To our knowledge, this is the first systematic analysis of host proteins targeted for cleavage during enterovirus infection. The data generated in this study will serve as a valuable resource for the research community in the quest to uncover the molecular details of enterovirus cell biology and disease pathogenesis.
Yu ZL, Yu YD, Wang F, Myasnikov AG, Coffino P, Cheng YF
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Allosteric coupling between alpha-rings of the 20S proteasome

NATURE COMMUNICATIONS 2020 SEP 11; 11(1):? Article 4580
Proteasomal machinery performs essential regulated protein degradation in eukaryotes. Classic proteasomes are symmetric, with a regulatory ATPase docked at each end of the cylindrical 20S. Asymmetric complexes are also present in cells, either with a single ATPase or with an ATPase and non-ATPase at two opposite ends. The mechanism that populates these different proteasomal complexes is unknown. Using archaea homologs, we construct asymmetric forms of proteasomes. We demonstrate that the gate conformation of the two opposite ends of 20S are coupled: binding one ATPase opens a gate locally, and also opens the opposite gate allosterically. Such allosteric coupling leads to cooperative binding of proteasomal ATPases to 20S and promotes formation of proteasomes symmetrically configured with two identical ATPases. It may also promote formation of asymmetric complexes with an ATPase and a non-ATPase at opposite ends. We propose that in eukaryotes a similar mechanism regulates the composition of the proteasomal population.
Marrocco J
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Bruce S. McEwen: the evolution of stress

STRESS-THE INTERNATIONAL JOURNAL ON THE BIOLOGY OF STRESS 2020 SEP 2; 23(5):497-498
Kereiakes DJ, Henry TD, DeMaria AN, Bentur O, Carlson M, Yue CS, Martin LH, Midkiff J, Mueller M, Meek T, Garza D, Gibson CM, Coller BS
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First Human Use of RUC-4: A Nonactivating Second-Generation Small-Molecule Platelet Glycoprotein IIb/IIIa (Integrin alpha IIb beta 3) Inhibitor Designed for Subcutaneous Point-of-Care Treatment of ST-Segment-Elevation Myocardial Infarction

JOURNAL OF THE AMERICAN HEART ASSOCIATION 2020 SEP 1; 9(17):? Article e016552
Background: Despite reductions in door-to-balloon times for primary coronary intervention, mortality from ST-segment-elevation myocardial infarction has plateaued. Early pre-primary coronary intervention treatment of ST-segment-elevation myocardial infarction with glycoprotein IIb/IIIa inhibitors improves pre-primary coronary intervention coronary flow, limits infarct size, and improves survival. We report the first human use of a novel glycoprotein IIb/IIIa inhibitor designed for subcutaneous first point-of-care ST-segment-elevation myocardial infarction treatment. Methods and Results: Healthy volunteers and patients with stable coronary artery disease receiving aspirin received escalating doses of RUC-4 or placebo in a sentinel-dose, randomized, blinded fashion. Inhibition of platelet aggregation (IPA) to ADP (20 mu mol/L), RUC-4 blood levels, laboratory evaluations, and clinical assessments were made through 24 hours and at 7 days. Doses were increased until reaching the biologically effective dose (the dose producing >= 80% IPA within 15 minutes, with return toward baseline within 4 hours). In healthy volunteers, 15 minutes after subcutaneous injection, mean +/- SD IPA was 6.9%+7.1% after placebo and 71.8%+/- 15.0% at 0.05 mg/kg (n=6) and 84.7%+/- 16.7% at 0.075 mg/kg (n=6) after RUC-4. IPA diminished over 90 to 120 minutes. In patients with coronary artery disease, 15 minutes after subcutaneous injection of placebo or 0.04 mg/kg (n=2), 0.05 mg/kg (n=6), and 0.075 mg/kg (n=18) of RUC-4, IPA was 14.6%+/- 11.7%, 53.6%+/- 17.0%, 76.9%+/- 10.6%, and 88.9%+/- 12.7%, respectively. RUC-4 blood levels correlated with IPA. Aspirin did not affect IPA or RUC-4 blood levels. Platelet counts were stable and no serious adverse events, bleeding, or injection site reactions were observed. Conclusions: RUC-4 provides rapid, high-grade, limited-duration platelet inhibition following subcutaneous administration that appears to be safe and well tolerated. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NTC03844191.
Farrell RJ, Ryan TA
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Local Sourcing of Secretory Proteins in Faraway Places

TRENDS IN NEUROSCIENCES 2020 SEP; 43(9):649-650
A recent paper by Carter et al. identifies a novel organelle, the ribosome-associated vesicle (RAV), that might serve as a portable, local factory for producing proteins destined for the secretory pathway. The appearance of RAVs in den-drites suggests they may serve to generate membrane and secreted proteins in distal processes.
Watkins TBK, Lim EL, Petkovic M, Elizalde S, Birkbak NJ, Wilson GA, Moore DA, Gronroos E, Rowan A, Dewhurst SM, Demeulemeester J, Dentro SC, Horswell S, Au L, Haase K, Escudero M, Rosenthal R, Al Bakir M, Xu H, Litchfield K, Lu WT, Mourikis TP, Dietzen M, Spain L, Cresswell GD, Biswas D, Lamy P, Nordentoft I, Harbst K, Castro-Giner F, Yates LR, Caramia F, Jaulin F, Vicier C, Tomlinson IPM, Brastianos PK, Cho RJ, Bastian BC, Dyrskjot L, Jonsson GB, Savas P, Loi S, Campbell PJ, Andre F, Luscombe NM, Steeghs N, Tjan-Heijnen VCG, Szallasi Z, Turajlic S, Jamal-Hanjani M, Van Loo P, Bakhoum SF, Schwarz RF, McGranahan N, Swanton C
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Pervasive chromosomal instability and karyotype order in tumour evolution

NATURE 2020 SEP 2; ?(?):?
Chromosomal instability in cancer consists of dynamic changes to the number and structure of chromosomes(1,2). The resulting diversity in somatic copy number alterations (SCNAs) may provide the variation necessary for tumour evolution(1,3,4). Here we use multi-sample phasing and SCNA analysis of 1,421 samples from 394 tumours across 22 tumour types to show that continuous chromosomal instability results in pervasive SCNA heterogeneity. Parallel evolutionary events, which cause disruption in the same genes (such asBCL9, MCL1,ARNT(also known asHIF1B),TERTandMYC) within separate subclones, were present in 37% of tumours. Most recurrent losses probably occurred before whole-genome doubling, that was found as a clonal event in 49% of tumours. However, loss of heterozygosity at the human leukocyte antigen (HLA) locus and loss of chromosome 8p to a single haploid copy recurred at substantial subclonal frequencies, even in tumours with whole-genome doubling, indicating ongoing karyotype remodelling. Focal amplifications that affected chromosomes 1q21 (which encompassesBCL9, MCL1andARNT), 5p15.33 (TERT), 11q13.3 (CCND1), 19q12 (CCNE1) and 8q24.1 (MYC) were frequently subclonal yet appeared to be clonal within single samples. Analysis of an independent series of 1,024 metastatic samples revealed that 13 focal SCNAs were enriched in metastatic samples, including gains in chromosome 8q24.1 (encompassingMYC) in clear cell renal cell carcinoma and chromosome 11q13.3 (encompassingCCND1) in HER2(+)breast cancer. Chromosomal instability may enable the continuous selection of SCNAs, which are established as ordered events that often occur in parallel, throughout tumour evolution. Chromosomal instability enables the continuous selection of somatic copy number alterations, which are established as ordered events that often occur in parallel, throughout tumour evolution and metastasis.
Schaeffer DJ, Selvanayagam J, Johnston KD, Menon RS, Freiwald WA, Everling S
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Face selective patches in marmoset frontal cortex

NATURE COMMUNICATIONS 2020 SEP 25; 11(1):? Article 4856
In humans and macaque monkeys, socially relevant face processing is accomplished via a distributed functional network that includes specialized patches in frontal cortex. It is unclear whether a similar network exists in New World primates, who diverged similar to 35 million years from Old World primates. The common marmoset is a New World primate species ideally placed to address this question given their complex social repertoire. Here, we demonstrate the existence of a putative high-level face processing network in marmosets. Like Old World primates, marmosets show differential activation in anterior cingulate and lateral prefrontal cortices while they view socially relevant videos of marmoset faces. We corroborate the locations of these frontal regions by demonstrating functional and structural connectivity between these regions and temporal lobe face patches. Given the evolutionary separation between macaques and marmosets, our results suggest this frontal network specialized for social face processing predates the separation between Platyrrhini and Catarrhini.