scholarly journals Adenovirus flow in host cell networks

Open Biology ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 190012 ◽  
Author(s):  
Justin W. Flatt ◽  
Sarah J. Butcher
Keyword(s):  
Viral Vectors ◽  
Host Cells ◽  
Local Network ◽  
Virion Production ◽  
Cellular Behaviour ◽  
The Right ◽  
Cell Networks ◽  
Novel Delivery Systems ◽  
Discrete Functions ◽  
Protein Vi

Viruses are obligatory parasites that take advantage of intracellular niches to replicate. During infection, their genomes are carried in capsids across the membranes of host cells to sites of virion production by exploiting cellular behaviour and resources to guide and achieve all aspects of delivery and the downstream virus manufacturing process. Successful entry hinges on execution of a precisely tuned viral uncoating program where incoming capsids disassemble in consecutive steps to ensure that genomes are released at the right time, and in the right place for replication to occur. Each step of disassembly is cell-assisted, involving individual pathways that transmit signals to regulate discrete functions, but at the same time, these signalling pathways are organized into larger networks, which communicate back and forth in complex ways in response to the presence of virus. In this review, we consider the elegant strategy by which adenoviruses (AdVs) target and navigate cellular networks to initiate the production of progeny virions. There are many remarkable aspects about the AdV entry program; for example, the virus gains targeted control of a large well-defined local network neighbourhood by coupling several interacting processes (including endocytosis, autophagy and microtubule trafficking) around a collective reference state centred on the interactional topology and multifunctional nature of protein VI. Understanding the network targeting activity of protein VI, as well as other built-in mechanisms that allow AdV particles to be efficient at navigating the subsystems of the cell, can be used to improve viral vectors, but also has potential to be incorporated for use in entirely novel delivery systems.

Inherent hepatocytic heterogeneity determines expression and retention of edited F9 alleles post-AAV/CRISPR infusion

2021 ◽  
Vol 118 (42) ◽  
pp. e2110887118
Author(s):  
Qiang Wang ◽  
Lin Zhang ◽  
Guo-Wei Zhang ◽  
Jian-Hua Mao ◽  
Xiao-Dong Xi ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Gene Editing ◽  
Regulatory Region ◽  
Factor Ix ◽  
Host Cells ◽  
Clotting Factor ◽  
Dependent Manner ◽  
Coding Region ◽  
Therapeutic Benefits

Infusing CRISPR/donor-loaded adeno-associated viral vectors (AAV/CRISPR) could enable in vivo hepatic gene editing to remedy hemophilia B (HB) with inherited deficiency of clotting factor IX (FIX). Yet, current regimens focus on correcting HB with simple mutations in the coding region of the F9, overlooking those carrying complicated mutations involving the regulatory region. Moreover, a possible adverse effect of treatment-related inflammation remains unaddressed. Here we report that a single DNA cutting-mediated long-range replacement restored the FIX-encoding function of a mutant F9 (mF9) carrying both regulatory and coding defects in a severe mouse HB model, wherein incorporation of a synthetic Alb enhancer/promoter-mimic (P2) ensured FIX elevation to clinically meaningful levels. Through single-cell RNA sequencing (scRNA-seq) of liver tissues, we revealed that a subclinical hepatic inflammation post-AAV/CRISPR administration regulated the vulnerability of the edited mF9-harboring host cells to cytotoxic T lymphocytes (CTLs) and the P2 activity in a hepatocytic subset–dependent manner via modulating specific sets of liver-enriched transcription factors (LETFs). Collectively, our study establishes an AAV/CRISPR-mediated gene-editing protocol applicable to complicated monogenetic disorders, underscoring the potentiality of improving therapeutic benefits through managing inflammation.

scholarly journals Viral vector-based tools advance knowledge of basal ganglia anatomy and physiology

2016 ◽  
Vol 115 (4) ◽  
pp. 2124-2146 ◽  
Author(s):  
Rachel J. Sizemore ◽  
Sonja Seeger-Armbruster ◽  
Stephanie M. Hughes ◽  
Louise C. Parr-Brownlie
Keyword(s):  
Basal Ganglia ◽  
Viral Vectors ◽  
Viral Vector ◽  
Therapeutic Potential ◽  
Host Cells ◽  
Designer Drugs ◽  
Designer Drug ◽  
Anatomy And Physiology ◽  
Optogenetic Stimulation ◽  
New Treatments

Viral vectors were originally developed to deliver genes into host cells for therapeutic potential. However, viral vector use in neuroscience research has increased because they enhance interpretation of the anatomy and physiology of brain circuits compared with conventional tract tracing or electrical stimulation techniques. Viral vectors enable neuronal or glial subpopulations to be labeled or stimulated, which can be spatially restricted to a single target nucleus or pathway. Here we review the use of viral vectors to examine the structure and function of motor and limbic basal ganglia (BG) networks in normal and pathological states. We outline the use of viral vectors, particularly lentivirus and adeno-associated virus, in circuit tracing, optogenetic stimulation, and designer drug stimulation experiments. Key studies that have used viral vectors to trace and image pathways and connectivity at gross or ultrastructural levels are reviewed. We explain how optogenetic stimulation and designer drugs used to modulate a distinct pathway and neuronal subpopulation have enhanced our mechanistic understanding of BG function in health and pathophysiology in disease. Finally, we outline how viral vector technology may be applied to neurological and psychiatric conditions to offer new treatments with enhanced outcomes for patients.

scholarly journals A Single Maturation Cleavage Site in Adenovirus Impacts Cell Entry and Capsid Assembly

2015 ◽  
Vol 90 (1) ◽  
pp. 521-532 ◽  
Author(s):  
Crystal L. Moyer ◽  
Eli S. Besser ◽  
Glen R. Nemerow
Keyword(s):  
Cleavage Site ◽  
Proteolytic Processing ◽  
Cell Entry ◽  
Host Cells ◽  
Nuclear Accumulation ◽  
Cell Infection ◽  
Particle Assembly ◽  
Capsid Shell ◽  
N Terminus ◽  
Protein Vi

ABSTRACTProteolytic maturation drives the conversion of stable, immature virus particles to a mature, metastable state primed for cell infection. In the case of human adenovirus, this proteolytic cleavage is mediated by the virally encoded protease AVP. Protein VI, an internal capsid cement protein and substrate for AVP, is cleaved at two sites, one of which is near the N terminus of the protein. In mature capsids, the 33 residues at the N terminus of protein VI (pVIn) are sequestered inside the cavity formed by peripentonal hexon trimers at the 5-fold vertex. Here, we describe a glycine-to-alanine mutation in the N-terminal cleavage site of protein VI that profoundly impacts proteolytic processing, the generation of infectious particles, and cell entry. The phenotypic effects associated with this mutant provide a mechanistic framework for understanding the multifunctional nature of protein VI. Based on our findings, we propose that the primary function of the pVIn peptide is to mediate interactions between protein VI and hexon during virus replication, driving hexon nuclear accumulation and particle assembly. Once particles are assembled, AVP-mediated cleavage facilitates the release of the membrane lytic region at the amino terminus of mature VI, allowing it to lyse the endosome during cell infection. These findings highlight the importance of a single maturation cleavage site for both infectious particle production and cell entry and emphasize the exquisite spatiotemporal regulation governing adenovirus assembly and disassembly.IMPORTANCEPostassembly virus maturation is a cornerstone principle in virology. However, a mechanistic understanding of how icosahedral viruses utilize this process to transform immature capsids into infection-competent particles is largely lacking. Adenovirus maturation involves proteolytic processing of seven precursor proteins. There is currently no information for the role of each independent cleavage event in the generation of infectious virions. To address this, we investigated the proteolytic maturation of one adenovirus precursor molecule, protein VI. Structurally, protein VI cements the outer capsid shell and links it to the viral core. Functionally, protein VI is involved in endosome disruption, subcellular trafficking, transcription activation, and virus assembly. Our studies demonstrate that the multifunctional nature of protein VI is largely linked to its maturation. Through mutational analysis, we show that disrupting the N-terminal cleavage of preprotein VI has major deleterious effects on the assembly of infectious virions and their subsequent ability to infect host cells.

scholarly journals Characterization of the hrpF Pathogenicity Peninsula of Xanthomonas oryzae pv. oryzae

2005 ◽  
Vol 18 (6) ◽  
pp. 546-554 ◽  
Author(s):  
Akiko Sugio ◽  
Bing Yang ◽  
Frank F. White
Keyword(s):  
Gene Clusters ◽  
Hypersensitive Reaction ◽  
Xanthomonas Oryzae ◽  
Host Cells ◽  
Host Specialization ◽  
Rice Cultivars ◽  
Type Iii Effectors ◽  
Type Iii ◽  
The Right ◽  
And Function

The hrp gene cluster of Xanthomonas spp. contains genes for the assembly and function of a type III secretion system (TTSS). The hrpF genes reside in a region between hpaB and the right end of the hrp cluster. The region of the hrpF gene of Xanthomonas oryzae pv. oryzae is bounded by two IS elements and also contains a homolog of hpaF of X. campestris pv. vesicatoria and two newly identified genes, hpa3 and hpa4. A comparison of the hrp gene clusters of different species of Xanthomonas revealed that the hrpF region is a constant yet more variable peninsula of the hrp pathogenicity island. Mutations in hpaF, hpa3, and hpa4 had no effect on virulence, whereas hrpF mutants were severely reduced in virulence on susceptible rice cultivars. The hrpF genes from X. campestris pv. vesicatoria, X. campestris pv. campestris, and X. axonopodis pv. citri each were capable of restoring virulence to the hrpF mutant of X. oryzae pv. oryzae. Correspondingly, none of the Xanthomonas pathovars with hrpF from X. oryzae pv. oryzae elicited a hypersensitive reaction in their respective hosts. Therefore, no evidence was found for hrpF as a host-specialization factor. In contrast to the loss of Bs3-dependent reactions by hrpF mutants of X. campestris pv. vesicatoria, hrpF mutants of X. oryzae pv. oryzae with either avrXa10 or avrXa7 elicited hypersensitive reactions in rice cultivars with the corresponding R genes. A double hrpFxoo-hpa1 mutant also elicited an Xa10-dependent resistance reaction. Thus, loss of hrpF, hpa1, or both may reduce delivery or effectiveness of type III effectors. However, the mutations did not completely prevent the delivery of effectors from X. oryzae pv. oryzae into the host cells.

scholarly journals Generation of viral vectors specific to neuronal subtypes of targeted brain regions by Enhancer-Driven Gene Expression (EDGE)

2019 ◽  
Author(s):  
Rajeevkumar Raveendran Nair ◽  
Stefan Blankvoort ◽  
Maria Jose Lagartos ◽  
Cliff Kentros
Keyword(s):  
Gene Expression ◽  
Brain Function ◽  
Viral Vectors ◽  
Neural Circuits ◽  
Tissue Sample ◽  
Transgenic Animals ◽  
Regulatory Elements ◽  
Brain Regions ◽  
Transgenic Lines ◽  
The Right

SummaryUnderstanding brain function requires understanding neural circuits at the level of specificity at which they operate. While recent years have seen the development of a variety of remarkable molecular tools for the study of neural circuits, their utility is currently limited by the inability to deploy them in specific elements of native neural circuits, i.e. particular neuronal subtypes. One can obtain a degree of specificity with neuron-specific promoters, but native promoters are almost never sufficiently specific restricting this approach to transgenic animals. We recently showed that one can obtain transgenic mice with augmented anatomical specificity in targeted brain regions by identifyingcis-regulatory elements (i.e. enhancers) uniquely active in those brain regions and combining them with a heterologous promoter, an approach we call EDGE (Enhancer-Driven Gene Expression). Here we extend this strategy to the generation of viral (rAAV) vectors, showing that when combined with the right minimal promoter they largely recapitulate the specificity seen in the corresponding transgenic lines in wildtype animals, even of another species. Because active enhancers can be identified in any tissue sample, this approach promises to enable the kind of circuit-specific manipulations in any species. This should not only greatly enhance our understanding of brain function, but may one day even provide novel therapeutic avenues to correct the imbalances in neural circuits underlying many disorders of the brain.

scholarly journals Recent Advances in the Development of Bio-Reducible Polymers for Efficient Cancer Gene Delivery Systems

2019 ◽  
Vol 2 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Kiel Sung Yong ◽  
◽  
Wan Kim Sung ◽  
◽  
◽  
...  
Keyword(s):  
Gene Therapy ◽  
Gene Delivery ◽  
Ribonucleic Acid ◽  
Viral Vectors ◽  
Delivery Systems ◽  
Host Cells ◽  
Viral Gene ◽  
Cancer Gene ◽  
Inherited Disorders ◽  
Messenger Ribonucleic Acid

Gene therapy is the unique method for the use of genetic materials such as Messenger ribonucleic acid (mRNA), plasmid deoxyribonucleic acid (pDNA), and small interfering ribonucleic acid (siRNA) into specific host-cells for the treatment of inherited disorders in any diseases. The successful way to utilize the gene therapy is to develop the efficient cancer gene delivery systems. In this paper, the successful and efficient gene delivery systems are briefly reviewed on the basis of bio-reducible polymeric systems for cancer therapy. The viral gene delivery systems such as RNA-based viral and DNA-based viral vectors are also discussed. The development of bio-reducible polymer for gene delivery system has briefly discussed for the efficient cancer gene delivery of viral vectors and non-viral vectors.

scholarly journals An entropic characterization of protein interaction networks and cellular robustness

2006 ◽  
Vol 3 (11) ◽  
pp. 843-850 ◽  
Author(s):  
Thomas Manke ◽  
Lloyd Demetrius ◽  
Martin Vingron
Keyword(s):  
Protein Interaction ◽  
Large Scale ◽  
Global Network ◽  
Molecular Networks ◽  
Local Network ◽  
Large Contribution ◽  
Fundamental Relation ◽  
Cellular Behaviour ◽  
Network Entropy

The structure of molecular networks is believed to determine important aspects of their cellular function, such as the organismal resilience against random perturbations. Ultimately, however, cellular behaviour is determined by the dynamical processes, which are constrained by network topology. The present work is based on a fundamental relation from dynamical systems theory, which states that the macroscopic resilience of a steady state is correlated with the uncertainty in the underlying microscopic processes, a property that can be measured by entropy. Here, we use recent network data from large-scale protein interaction screens to characterize the diversity of possible pathways in terms of network entropy. This measure has its origin in statistical mechanics and amounts to a global characterization of both structural and dynamical resilience in terms of microscopic elements. We demonstrate how this approach can be used to rank network elements according to their contribution to network entropy and also investigate how this suggested ranking reflects on the functional data provided by gene knockouts and RNAi experiments in yeast and Caenorhabditis elegans . Our analysis shows that knockouts of proteins with large contribution to network entropy are preferentially lethal. This observation is robust with respect to several possible errors and biases in the experimental data. It underscores the significance of entropy as a fundamental invariant of the dynamical system, and as a measure of structural and dynamical properties of networks. Our analytical approach goes beyond the phenomenological studies of cellular robustness based on local network observables, such as connectivity. One of its principal achievements is to provide a rationale to study proxies of cellular resilience and rank proteins according to their importance within the global network context.

Endovascular Restorative Neurosurgery: A Novel Concept for Molecular and Cellular Therapy of the Nervous System

Neurosurgery ◽  
2003 ◽  
Vol 52 (2) ◽  
pp. 402-413 ◽  
Author(s):  
Arun Paul Amar ◽  
Berislav V. Zlokovic ◽  
Michael L.J. Apuzzo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Gene Transfer ◽  
Viral Vectors ◽  
Developmental Disorders ◽  
Cellular Therapy ◽  
Genetically Engineered ◽  
Host Cells ◽  
The Central Nervous System ◽  
The Brain

Abstract THE AMALGAM OF molecular biology and neurosurgery offers immense promise for neurorestoration and the management of neurodegenerative deficiencies, developmental disorders, neoplasms, stroke, and trauma. This article summarizes present strategies for and impediments to gene therapy and stem cell therapy of the central nervous system and advances the concept of a potential new approach, namely endovascular restorative neurosurgery. The objectives of gene transfer to the central nervous system are efficient transfection of host cells, selective sustained expression of the transgene, and lack of toxicity or immune excitation. The requisite elements of this process are the identification of candidate diseases, the construction of vehicles for gene transfer, regulated expression, and physical delivery. In the selection of target disorders, the underlying genetic events to be overcome, as well as their spatial and temporal distributions, must be considered. These factors determine the requirements for the physical dispersal of the transgene, the duration of transgene expression, and the quantity of transgene product needed to abrogate the disease phenotype. Vehicles for conveying the transgene to the central nervous system include viral vectors (retroviruses, lentiviruses, adenoviruses, adeno-associated viruses, and herpes simplex virus), liposomes, and genetically engineered cells, including neural stem cells. Delivery of the transgene into the brain presents several challenges, including limited and potentially risky access through the cranium, sensitivity to volumetric changes, restricted diffusion, and the blood-brain barrier. Genetic or cellular therapeutic agents may be injected directly into the brain parenchyma (via stereotaxy or craniotomy), into the cerebrospinal fluid (in the ventricles or cisterns), or into the bloodstream (intravenously or intra-arterially). The advantages of the endovascular route include the potential for widespread distribution, the ability to deliver large volumes, limited perturbation of neural tissue, and the feasibility of repeated administration.

scholarly journals Novel molecular approaches to cystic fibrosis gene therapy

2005 ◽  
Vol 387 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Tim W. R. LEE ◽  
David A. MATTHEWS ◽  
G. Eric BLAIR
Keyword(s):  
Cystic Fibrosis ◽  
Gene Therapy ◽  
Gene Delivery ◽  
Viral Vectors ◽  
Bronchial Tree ◽  
Endosomal Escape ◽  
Host Cells ◽  
Cystic Fibrosis Gene ◽  
Viral Gene ◽  
Molecular Approaches

Gene therapy holds promise for the treatment of a range of inherited diseases, such as cystic fibrosis. However, efficient delivery and expression of the therapeutic transgene at levels sufficient to result in phenotypic correction of cystic fibrosis pulmonary disease has proved elusive. There are many reasons for this lack of progress, both macroscopically in terms of airway defence mechanisms and at the molecular level with regard to effective cDNA delivery. This review of approaches to cystic fibrosis gene therapy covers these areas in detail and highlights recent progress in the field. For gene therapy to be effective in patients with cystic fibrosis, the cDNA encoding the cystic fibrosis transmembrane conductance regulator protein must be delivered effectively to the nucleus of the epithelial cells lining the bronchial tree within the lungs. Expression of the transgene must be maintained at adequate levels for the lifetime of the patient, either by repeat dosage of the vector or by targeting airway stem cells. Clinical trials of gene therapy for cystic fibrosis have demonstrated proof of principle, but gene expression has been limited to 30 days at best. Results suggest that viral vectors such as adenovirus and adeno-associated virus are unsuited to repeat dosing, as the immune response reduces the effectiveness of each subsequent dose. Nonviral approaches, such as cationic liposomes, appear more suited to repeat dosing, but have been less effective. Current work regarding non-viral gene delivery is now focused on understanding the mechanisms involved in cell entry, endosomal escape and nuclear import of the transgene. There is now increasing evidence to suggest that additional ligands that facilitate endosomal escape or contain a nuclear localization signal may enhance liposome-mediated gene delivery. Much progress in this area has been informed by advances in our understanding of the mechanisms by which viruses deliver their genomes to the nuclei of host cells.

scholarly journals Self-Amplifying RNA Viruses as RNA Vaccines

2020 ◽  
Vol 21 (14) ◽  
pp. 5130 ◽  
Author(s):  
Kenneth Lundstrom
Keyword(s):  
Immune Responses ◽  
Viral Vectors ◽  
Ebola Virus ◽  
Tumor Antigens ◽  
Vaccine Development ◽  
Rna Viruses ◽  
Emerging Diseases ◽  
Host Cells ◽  
Phase Iii ◽  
Rna Replicon

Single-stranded RNA viruses such as alphaviruses, flaviviruses, measles viruses and rhabdoviruses are characterized by their capacity of highly efficient self-amplification of RNA in host cells, which make them attractive vehicles for vaccine development. Particularly, alphaviruses and flaviviruses can be administered as recombinant particles, layered DNA/RNA plasmid vectors carrying the RNA replicon and even RNA replicon molecules. Self-amplifying RNA viral vectors have been used for high level expression of viral and tumor antigens, which in immunization studies have elicited strong cellular and humoral immune responses in animal models. Vaccination has provided protection against challenges with lethal doses of viral pathogens and tumor cells. Moreover, clinical trials have demonstrated safe application of RNA viral vectors and even promising results in rhabdovirus-based phase III trials on an Ebola virus vaccine. Preclinical and clinical applications of self-amplifying RNA viral vectors have proven efficient for vaccine development and due to the presence of RNA replicons, amplification of RNA in host cells will generate superior immune responses with significantly reduced amounts of RNA delivered. The need for novel and efficient vaccines has become even more evident due to the global COVID-19 pandemic, which has further highlighted the urgency in challenging emerging diseases.

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