Publications by authors named "Vincent Ha"

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that infects the majority of the world's population. Lytic HCMV replication in immunocompromised individuals or neonates can lead to severe disease in multiple organ systems and even death. The establishment of lytic replication is driven by the first viral proteins expressed upon infection, the immediate early proteins, which play a key role in creating an intracellular environment conducive to virus replication.

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Unlabelled: Many viruses have evolved structured RNA elements that can influence transcript abundance and translational efficiency, and help evade host immune factors by hijacking cellular machinery during replication. Here, we evaluated the functional impact of sub-genomic flaviviral RNAs (sfRNAs) known to stall exoribonuclease activity, by incorporating these elements into recombinant adeno-associated viral (AAV) genome cassettes. Specifically, sfRNAs from Dengue, Zika, Japanese Encephalitis, Yellow Fever, Murray Valley Encephalitis, and West Nile viruses increased transcript stability and transgene expression compared to a conventional woodchuck hepatitis virus element (WPRE).

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RNA performs a wide variety of vital cellular functions. These functions typically require interactions with other biological macromolecules, often as part of an intricate communication network. High-throughput techniques capable of analyzing RNA-based interactions are therefore essential.

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The ability to enzymatically assemble DNA oligonucleotides into longer DNA duplexes in a process known as gene synthesis has wide-ranging applications in the fields of genetic engineering and synthetic biology. Thermodynamically balanced inside-out (TBIO) gene synthesis is one of several PCR-based primer extension gene synthesis protocols that have been developed. In TBIO gene synthesis, overlapping primers with equivalent melting temperatures (Ts) are designed so that the 5' half of the DNA is encoded by sense primers and the 3' half of the DNA molecule is encoded by antisense primers.

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Adeno-associated viruses (AAV) rely on helper viruses to transition from latency to lytic infection. Some AAV serotypes are secreted in a pre-lytic manner as free or extracellular vesicle (EV)-associated particles, although mechanisms underlying such are unknown. Here, we discover that the membrane-associated accessory protein (MAAP), expressed from a frameshifted open reading frame in the AAV cap gene, is a novel viral egress factor.

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Introduction: The metastatic pancreatic adenocarcinoma clinical trial (MPACT) trial established gemcitabine (gem) and nab-paclitaxel (nab) as a standard treatment for pancreatic cancer utilizing granulocyte colony-stimulating factors to manage neutropenia. This was a challenge for jurisdictions that do not use granulocyte colony-stimulating factors in palliative settings. We developed dosage guidelines to dose modify gem and nab without granulocyte colony-stimulating factors.

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Background: Body composition is increasingly being studied as a method of predicting chemotherapy toxicity. Our study aimed to evaluate associations of body composition with treatment toxicity in a group of pancreatic cancer patients treated with gemcitabine plus nab-paclitaxel.

Methods: A retrospective review was performed for all patients who received first-line gemcitabine plus nab-paclitaxel for metastatic pancreatic cancer at a northern Alberta cancer institute (Canada) from 2014 to 2017.

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Regulatory RNA-based interactions are critical for coordinating gene expression and are increasingly being targeted in synthetic biology, antimicrobial, and therapeutic fields. Bacterial -encoded small RNAs (sRNAs) regulate the translation and/or stability of mRNA targets through base-pairing interactions. These interactions are often integral to complex gene circuits which coordinate critical bacterial processes.

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The increase in antibacterial resistance is a serious challenge for both the health and defence sectors and there is a need for both novel antibacterial targets and antibacterial strategies. RNA degradation and ribonucleases, such as the essential endoribonuclease RNase E, encoded by the gene, are emerging as potential antibacterial targets while antisense oligonucleotides may provide alternative antibacterial strategies. As mRNA has not been previously targeted using an antisense approach, we decided to explore using antisense oligonucleotides to target the translation initiation region of the mRNA.

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Present in all organisms, DNA ligases catalyse the formation of a phosphodiester bond between a 3' hydroxyl and a 5' phosphate, a reaction that is essential for maintaining genome integrity during replication and repair. Eubacterial DNA ligases use NAD as a cofactor and possess low sequence and structural homology relative to eukaryotic DNA ligases which use ATP as a cofactor. These key differences enable specific targeting of bacterial DNA ligases as an antibacterial strategy.

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Circular RNAs (circRNAs) are highly stable RNA molecules that are attractive templates for expression of therapeutic proteins and non-coding RNAs. In eukaryotes, circRNAs are primarily generated by the spliceosome through backsplicing. Here, we interrogate different molecular elements including intron type and length, repeats, internal ribosome entry sites (IRESs), and exon length essential for circRNA formation and exploit this information to engineer robust backsplicing and circRNA expression.

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Article Synopsis
  • Chikungunya virus (CHIKV) is a mosquito-borne virus that leads to severe joint pain and has no approved treatments, highlighting the need for better understanding of its biology and replication mechanisms.
  • Researchers investigated the RNA secondary structures in the CHIKV genome using SHAPE-MaP, identifying 23 stable regions, including four known structures that are critical for the virus's function.
  • The study also examined variants of the 3'UTR region affecting virus replication, discovering novel RNA structures and a duplication that increases unstructured RNA, which could impact viral replication in mosquito cells.
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Adeno-associated viruses (AAVs) are dependoparvoviruses that have proven useful for therapeutic gene transfer; however, our understanding of host factors that influence AAV trafficking and transduction is still evolving. Here, we investigated the role of cellular calcium in the AAV infectious pathway. First, we demonstrated a critical role for the host Golgi compartment-resident ATP-powered calcium pump (secretory pathway calcium ATPase 1 [SPCA1]) encoded by the gene in AAV infection.

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Coronaviruses, including SARS-CoV-2 the etiological agent of COVID-19 disease, have caused multiple epidemic and pandemic outbreaks in the past 20 years. With no vaccines, and only recently developed antiviral therapeutics, we are ill equipped to handle coronavirus outbreaks. A better understanding of the molecular mechanisms that regulate coronavirus replication and pathogenesis is needed to guide the development of new antiviral therapeutics and vaccines.

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Increasing resistance of bacteria to antibiotics is a serious global challenge and there is a need to unlock the potential of novel antibacterial targets. One such target is the essential prokaryotic endoribonuclease RNase E. Using a combination of high-throughput screening and validation we have identified three novel small molecule inhibitors of RNase E that are active against RNase E from , and .

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Introduction: Patients with advanced cancer often experience symptoms including pain, nausea, anorexia, fatigue, and depression. High symptom burden can be alleviated by multidisciplinary palliative care (PC) teams practicing symptom-directed management. Patients who are unable to access such services may be at higher risk of increased symptoms and poor outcomes.

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Human cytomegalovirus (HCMV) manipulates multiple cellular processes to facilitate virus replication, including the control of mRNA translation. We previously showed that the HCMV TRS1 protein (pTRS1) promotes cap-dependent mRNA translation independent of its ability to antagonize the antiviral protein PKR. Here we find that pTRS1 enhances internal ribosome entry site (IRES) activity using a novel circular RNA reporter that lacks an mRNA cap and poly(A) tail.

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A major limitation of current humanized mouse models is that they primarily enable the analysis of human-specific pathogens that infect hematopoietic cells. However, most human pathogens target other cell types, including epithelial, endothelial and mesenchymal cells. Here, we show that implantation of human lung tissue, which contains up to 40 cell types, including nonhematopoietic cells, into immunodeficient mice (lung-only mice) resulted in the development of a highly vascularized lung implant.

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Regulation of gene expression through processing and turnover of RNA is a key mechanism that allows bacteria to rapidly adapt to changing environmental conditions. Consequently, RNA degrading enzymes (ribonucleases; RNases) such as the endoribonuclease RNase E, frequently play critical roles in pathogenic bacterial virulence and are potential antibacterial targets. RNase E consists of a highly conserved catalytic domain and a variable non-catalytic domain that functions as the structural scaffold for the multienzyme degradosome complex.

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The discovery and engineering of more and more functions of RNA has highlighted the utility of RNA-targeting small molecules. Recently, several fluorogen-binding RNA aptamers have been developed that have been applied to live cell imaging of RNA and metabolites as RNA tags or biosensors, respectively. Although the design and application of these fluorogen-binding RNA aptamer-based devices is straightforward in theory, in practice, careful optimisation is required.

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The development of programmable regulators that precisely and predictably control gene expression is a major goal of synthetic biology. Consequently, rapid high-throughput biochemical methods capable of quantitatively analyzing all components of gene expression would be of value in the characterization and optimization of regulator performance. In this study we demonstrate a novel application of RNA arrays, involving the production of reporter-protein arrays, to gene expression analysis.

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Background: First-line adjuvant chemotherapy options for early-stage colorectal cancer (CRC) include CapeOx (capecitabine, intravenous oxaliplatin) and FOLFOX (intravenous 5-fluorouracil, leucovorin, oxaliplatin). Capecitabine is an oral prodrug analog of 5-fluorouracil, and recent studies have suggested that proton pump inhibitors (PPIs) may detrimentally affect capecitabine efficacy. Conversely, some literature suggests that PPIs may negatively affect CRC itself.

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Lysosomes maintain immune homeostasis through the degradation of phagocytosed apoptotic debris; however, the signaling events regulating lysosomal maturation remain undefined. In this study, we show that lysosome acidification, key to the maturation process, relies on mTOR complex 2 (mTORC2), activation of caspase-1, and cleavage of Rab39a. Mechanistically, the localization of cofilin to the phagosome recruits caspase-11, which results in the localized activation of caspase-1.

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We are just beginning to unravel the myriad of interactions in which non-coding RNAs participate. The intricate RNA interactome is the foundation of many biological processes, including bacterial virulence and human disease, and represents unexploited resources for the development of potential therapeutic interventions. However, identifying specific associations of a given RNA from the multitude of possible binding partners within the cell requires robust high-throughput systems for their rapid screening.

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Article Synopsis
  • Alphaviruses, like Sindbis virus (SINV) and Venezuelan equine encephalitis virus (VEEV), are mosquito-borne pathogens that cause a range of human diseases, highlighting the need to understand their RNA structural elements and their roles in viral replication and disease severity.!* -
  • Using a technique called SHAPE-MaP, researchers identified both known and novel RNA structures within the SINV and VEEV genomes, including a new functional element in SINV that impacts its infectivity when disrupted.!* -
  • The study found that although RNA structural elements are crucial for alphavirus biology, these structures are not conserved between SINV and VEEV, suggesting that alphaviruses often evolve
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