Biology subjects

Nguyen, T. T.

Publications and source records attributed to Nguyen, T. T..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Assessment of technical and clinical utility of a bead-based flow cytometry platform for multiparametric phenotyping of CNS-derived extracellular vesicles

Extracellular vesicles (EVs) derived from the CNS are potential liquid-biopsy markers for early detection and monitoring of neurodegenerative diseases and brain tumors. This study assessed the performance of a bead-based flow cytometry assay (EV Neuro) for multiparametric detection of CNS-derived EVs and identification of disease-specific markers. Different sample materials and EV isolation methods were compared. Glioblastoma- and primary human astrocyte-derived EVs exhibited distinct EV profiles, with signal intensities increasing with higher EV input. Analysis of serum or plasma from glioblastoma, multiple sclerosis, Alzheimers Disease patients and healthy controls showed varying marker signal intensities. Notably, data normalization improved marker identification. Specific EV populations, such as CD36+EVs in glioblastoma and GALC+EVs in multiple sclerosis, were significantly elevated in disease compared to controls. Clustering analysis techniques effectively differentiated glioblastoma patients from controls. A potential correlation between CD107a+EVs and neurofilament levels in the blood was identified in multiple sclerosis patients. Together, the semi-quantitative EV Neuro assay demonstrated its utility for EV profiling in complex samples. However, reliable statistical results in biomarker studies require large sample cohorts and high effect sizes. Nonetheless, this exploratory trial confirmed the feasibility of discovering EV-associated biomarkers and monitoring circulating EV profiles in CNS diseases using the EV Neuro assay.

neuroscience↗

bioRxiv2023

Chimeric oncolytic adenovirus evades neutralizing antibodies from human patients and exhibits enhanced anti-glioma efficacy in immunized mice

BACKGROUNDOncolytic adenoviruses, such as Delta-24-RGD, show promise as a potential breakthrough in treating patients with high-grade gliomas. However, their effectiveness against gliomas can be hindered by the presence of neutralizing antibodies. METHODSProduction of human neutralizing antibodies against adenoviruses was assessed in two cohorts of patients with malignant gliomas treated with Delta-24-RGD in a phase 1 clinical trial. Sera containing neutralizing antibodies were also obtained from mice immunized with intramuscular injections of wild-type Ad5. Chimeric adenovirus was constructed using molecular cloning, and its activity was assessed in vitro using quantitative PCR, western blot, and transmission electron microscopy. The therapeutic efficacy of the chimeric virus was tested in vivo using sera from patients previously treated with Delta-24-RGD and immunocompetent murine models of glioma. RESULTSExamination of sera from patients with malignant gliomas treated with Delta-24-RGD revealed that in the cohort treated with multiple injections of this oncolytic adenovirus, a higher percentage of patients developed neutralizing antibodies when compared to the patients treated with a single injection of Delta-24-RGD. Of note, long-term survival was only observed in patients who received a single injection. Delta-24-RGD-H43m, a chimeric oncolytic adenovirus engineered to overcome virus neutralization, demonstrated a potent anti-glioma effect both in vitro and in vivo. This chimeric virus showed resilience against anti-Ad5 neutralizing antibodies and conferred better therapeutic efficacy compared to Delta-24-RGD in mice with immunity against Ad5. Of further clinical relevance, Delta-24-RGD-H43m also evaded the inhibitory effects of sera from human patients treated with Delta-24-RGD. CONCLUSIONSThe development of neutralizing antibodies due to multiple virus injections was associated with lower frequency of long-term survivors in a clinical trial. The new chimeric virus shows increased resilience to inactivation by the sera of human patients compared to the parental virus. These findings lay the foundation for a novel oncolytic virus treatment approach targeting a significant percentage of glioma patients with prior exposure to adenovirus.

cancer biology↗

bioRxiv2023

Pasa: Leverage population pangenome graph to scaffold prokaryote genome assemblies.

Whole genome sequencing has increasingly become the essential method for studying the genetic mechanisms of antimicrobial resistance and for surveillance of drug-resistant bacterial pathogens. The majority of bacterial genomes sequenced to date have been sequenced with Illumina sequencing technology, owing to its high-throughput, excellent sequence accuracy, and low cost. However, because of the short-read nature of the technology, these assemblies are fragmented into large numbers of contigs, hindering the obtaining of full information of the genome. We develop Pasa, a graph-based algorithm that utilizes the pangenome graph and the assembly graph information to improve scaffolding quality. By leveraging the population information of the bacteria species, Pasa is able to utilize the linkage information of the gene families of the species to resolve the contig graph of the assembly. We show that our method outperforms the current state of the art in terms of accuracy, and at the same time, is computationally efficient to be applied to a large number of existing draft assemblies.

bioinformatics↗

bioRxiv2023

PanTA: An ultra-fast method for constructing large and growing microbial pangenomes

Pangenome analysis is an indispensable step in bacterial genomics to address the high variability of bacteria genomes. However, speed and scalability remain a challenge for pangenome inference software tools to cope with the fast-growing genomic collections. We present PanTA, a software package for constructing the pangenomes of large bacterial collections. We show that PanTA exhibits an unprecedented multiple times more efficient than the current state-of-the-arts while maintaining a similar pangenome accuracy. In addition, PanTA introduces a novel mechanism to construct the pangenome progressively where new samples are added into an existing pangenome without rebuilding the accumulated collection from scratch. In the progressive mode, PanTA is demonstrated to consume orders of magnitude less computational resource than existing solutions in managing the pangenomes of growing microbial datasets. We further show that PanTA can build the pangenome of the entire collection of >28000 Escherichia coli genomes from the RefSeq database on a laptop computer in 32 hours, highlighting the scalability and practicality of PanTA.The software is open source and is publicly available at https://github.com/amromics/panta under an MIT license.

bioinformatics↗

bioRxiv2023

TFAP2 paralogs regulate midfacial development in part through a conserved ALX genetic pathway.

Cranial neural crest development is governed by positional gene regulatory networks (GRNs). Fine-tuning of the GRN components underly facial shape variation, yet how those in the midface are connected and activated remain poorly understood. Here, we show that concerted inactivation of Tfap2a and Tfap2b in the murine neural crest even during the late migratory phase results in a midfacial cleft and skeletal abnormalities. Bulk and single-cell RNA-seq profiling reveal that loss of both Tfap2 members dysregulated numerous midface GRN components involved in midface fusion, patterning, and differentiation. Notably, Alx1/3/4 (Alx) transcript levels are reduced, while ChIP-seq analyses suggest TFAP2 directly and positively regulates Alx gene expression. TFAP2 and ALX co-expression in midfacial neural crest cells of both mouse and zebrafish further implies conservation of this regulatory axis across vertebrates. Consistent with this notion, tfap2a mutant zebrafish present abnormal alx3 expression patterns, and the two genes display a genetic interaction in this species. Together, these data demonstrate a critical role for TFAP2 in regulating vertebrate midfacial development in part through ALX transcription factor gene expression.

developmental biology↗

bioRxiv2023

CISD3 is required for Complex I function, mitochondrial integrity, and skeletal muscle maintenance

Mitochondria play a central role in muscle metabolism and function. In skeletal muscles, a unique family of iron-sulfur proteins, termed CISD proteins, support mitochondrial function. The abundance of these proteins declines with aging leading to muscle degeneration. Although the function of the outer mitochondrial proteins CISD1 and CISD2 has been defined, the role of the inner mitochondrial protein CISD3, is currently unknown. Here we show that CISD3 deficiency in mice results in muscle atrophy that shares proteomic features with Duchenne Muscular Dystrophy. We further reveal that CISD3 deficiency impairs the function and structure of skeletal muscle mitochondria, and that CISD3 interacts with, and donates its clusters to, Complex I respiratory chain subunit NDUFV2. These findings reveal that CISD3 is important for supporting the biogenesis and function of Complex I, essential for muscle maintenance and function. Interventions that target CISD3 could therefore impact muscle degeneration syndromes, aging, and related conditions.

cell biology↗

bioRxiv2023

Monocyte-derived Dll4 is a novel contributor to persistent systemic inflammation in HIV patients

BackgroundIn people living with HIV (PLWH) on combination antiretroviral therapy (cART), persistent systemic inflammation is a driving force for the progression of comorbidities, such as cardiovascular and cerebrovascular diseases. In this context, monocyte- and macrophage-related inflammation rather than T cell activation is a major cause of chronic inflammation. However, the underlying mechanism of how monocytes cause persistent systemic inflammation in PLWH is elusive. Methods and ResultsIn vitro, we demonstrated that lipopolysaccharides (LPS) or tumor necrosis factor alpha (TNF), induced a robust increase of Delta-like ligand 4 (Dll4) mRNA and protein expression in human monocytes and Dll4 secretion (extracellular Dll4, exDll4) from monocytes. Enhanced membrane-bound Dll4 (mDll4) expression in monocytes triggered Notch1 activation to promote pro-inflammatory factors expression. Dll4 silencing and inhibition of Nocth1 activation diminished the LPS or TNF -induced inflammation. exDll4 releases in response to cytokines occurred in monocytes but not endothelial cells or T cells. In clinical specimens, we found that PLWH, both male and female, on cART, showed a significant increase in mDll4 expression, activation of Dll4-Notch1 signaling, and inflammatory markers in monocytes. Although there was no sex effect on mDII4 in PLWH, plasma exDll4 was significantly elevated in males but not females compared to HIV uninfected individuals. Furthermore, exDll4 plasma levels paralleled with monocytes mDll4 in male PLWH. Circulating exDll4 was also positively associated with pro-inflammatory monocytes phenotype and negatively associated with classic monocytes phenotype in male PLWH. ConclusionPro-inflammatory stimuli increase Dll4 expression and Dll4-Notch1 signaling activation in monocytes and enhance monocyte proinflammatory phenotype, contributing to persistent systemic inflammation in male and female PLWH. Therefore, monocyte mDll4 could be a potential biomarker and therapeutic target of systemic inflammation. Plasma exDll4 may also play an additional role in systemic inflammation but primarily in men.

molecular biology↗

bioRxiv2023

A rapid genome-wide analysis of isolated giant viruses only using MinION sequencing

Following the discovery of Acanthamoeba polyphaga mimivirus, diverse giant viruses have been isolated. However, only a small fraction of these isolates has been completely sequenced, limiting our understanding of the genomic diversity of giant viruses. MinION is a portable and low-cost long-read sequencer that can be readily used in a laboratory. Although MinION provides highly error-prone reads that require correction through additional short-read sequencing, recent studies assembled high-quality microbial genomes only using MinION sequencing. Here, we evaluated the accuracy of MinION-only genome assemblies for giant viruses by re-sequencing a prototype marseillevirus. Assembled genomes presented over 99.98% identity to the reference genome with a few gaps, demonstrating a high accuracy of the MinION-only assembly. As a proof of concept, we de novo assembled five newly isolated viruses. Average nucleotide identities to their closest known relatives suggest that the isolates represent new species of marseillevirus, pithovirus, and mimivirus. Assembly of subsampled reads demonstrated that their taxonomy and genomic composition could be analyzed at the 50x sequencing coverage. We also identified a pithovirus gene whose homologues were detected only in metagenome-derived relatives. Collectively, we propose that MinION-only assembly is an effective approach to rapidly perform a genome-wide analysis of isolated giant viruses.

microbiology↗

bioRxiv2023

A cell state specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma

Glioma cells hijack developmental transcriptional programs to control cell state. During neural development, lineage trajectories rely on specialized metabolic pathways. However, the link between tumor cell state and metabolic programs is poorly understood in glioma. Here we uncover a glioma cell state-specific metabolic liability that can be leveraged therapeutically. To model cell state diversity, we generated genetically engineered murine gliomas, induced by deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling cellular fate. N1IC tumors harbored quiescent astrocyte-like transformed cell states while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. N1IC cells exhibit distinct metabolic alterations, with mitochondrial uncoupling and increased ROS production rendering them more sensitive to inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Importantly, treating patient-derived organotypic slices with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles.

cancer biology↗

bioRxiv2022

The effects of multifactorial stress combination on rice and maize

The complexity of environmental factors affecting plants is gradually increasing due to global warming, an increase in the number and intensity of climate change-driven weather events, such as droughts, heat waves, and floods, and the accumulation of different pollutants. The impact of multiple stress conditions on plants was recently termed multifactorial stress combination (MFSC) and defined as the occurrence of three or more stressors that impact plants simultaneously or sequentially. We recently reported that with the increased number and complexity of different stressors, the growth and survival of Arabidopsis thaliana seedlings declines; even if the level of each individual stress is low enough to have no significant effect on plants. This finding is alarming since it reveals that MFSCs of different low-level stressors could impact crops and cause a dramatic reduction in overall growth. However, whether MFSC would impact commercial crop cultivars has not been studied. Here, we reveal that a MFSC of 5 different low level abiotic stresses (salinity, heat, the herbicide paraquat, phosphorus deficiency, and the heavy metal cadmium), applied in an increasing level of complexity, has a significant negative impact on the growth and biomass of a commercial rice (Oryza sativa) cultivar and a maize (Zea mays) hybrid. We further report on the first proteomics analysis of MFSC in plants that identified over 300 proteins common to all 4- and 5-MFSCs. Taken together our findings reveal that the impacts of MFSC on two different crop species are severe, and that MFSC may significantly affect agricultural productivity.

plant biology↗

bioRxiv2022

Novel EGFR-Mutant Mouse Models of Lung Adenocarcinoma Reveal Adaptive Immunity Requirement for Durable Osimertinib Response

Lung cancers bearing oncogenically-mutated EGFR represent a significant fraction of lung adenocarcinomas (LUADs) for which EGFR-targeting tyrosine kinase inhibitors (TKIs) provide a highly effective therapeutic approach. However, these lung cancers eventually acquire resistance and undergo progression within a characteristically broad treatment duration range. Our previous study of EGFR mutant lung cancer biopsies highlighted the positive association of a TKI-induced interferon {gamma} transcriptional response with increased time to treatment progression. To test the hypothesis that host immunity contributes to the TKI response, we developed novel genetically-engineered mouse models of EGFR mutant lung cancer bearing exon 19 deletions (del19) or the L860R missense mutation. Both oncogenic EGFR mouse models developed multifocal LUADs from which transplantable cancer cell lines sensitive to the EGFR-specific TKIs, gefitinib and osimertinib, were derived. When propagated orthotopically in the left lungs of syngeneic C57BL/6 mice, deep and durable shrinkage of the cell line-derived tumors was observed in response to daily treatment with osimertinib. By contrast, orthotopic tumors propagated in immune deficient nu/nu mice exhibited modest tumor shrinkage followed by rapid progression on continuous osimertinib treatment. Importantly, osimertinib treatment significantly increased intratumoral CD3+ T cell content relative to diluent treatment. The findings provide strong evidence supporting the requirement for adaptive immunity in the durable therapeutic control of EGFR mutant lung cancer.

cancer biology↗

bioRxiv2022

An ER phospholipid hydrolase drives ER-associated mitochondrial constriction for fission and fusion

Mitochondria are dynamic organelles that undergo cycles of fission and fusion at a unified platform defined by endoplasmic reticulum (ER)-mitochondria membrane contact sites (MCSs). These MCSs or nodes co-localize fission and fusion machinery. We set out to identify how ER-associated mitochondrial nodes can regulate both fission and fusion machinery assembly. We have used a promiscuous biotin ligase linked to the fusion machinery, Mfn1, and proteomics to identify an ER membrane protein, Aphyd, as a major regulator of node formation. In the absence of Aphyd, fission and fusion machineries fail to recruit to ER-associated mitochondrial nodes and fission and fusion rates are significantly reduced. Aphyd contains an acyltransferase motif and an /{beta} hydrolase domain and point mutations in critical residues of these regions fail to rescue the formation of ER-associated mitochondrial hot spots. These data suggest a mechanism whereby Aphyd functions by altering phospholipid composition at ER-mitochondria MCSs. Our data present the first example of an ER membrane protein that regulates the recruitment of both fission and fusion machineries to mitochondria.

cell biology↗

bioRxiv2022

Characterizing the differential distribution and targets of Sumo paralogs in the mouse brain

SUMOylation is an evolutionarily conserved and essential mechanism whereby Small Ubiquitin Like Modifiers, or SUMO proteins (Sumo in mice), are covalently bound to protein substrates in a highly dynamic and reversible manner. SUMOylation is involved in a variety of basic neurological processes including learning and memory, and central nervous system development, but is also linked with neurological disorders. However, studying SUMOylation in vivo remains challenging due to limited tools to study Sumo proteins and their targets in their native context. More complexity arises from the fact that Sumo1 and Sumo2 are [~]50% homologous, whereas Sumo2 and Sumo3 are nearly identical and indistinguishable with antibodies. While Sumo paralogues can compensate for one anothers loss, Sumo2 is highest expressed and only paralog essential for embryonic development making it critical to uncover roles specific to Sumo2 in vivo. To further examine the roles of Sumo2, and to begin to tease apart the redundancy and similarity between key Sumo paralogs, we generated (His6-)HA epitope-tagged Sumo2 knock-in mouse alleles, expanding the current Sumo knock-in mouse tool-kit comprising of the previously generated His6-HA-Sumo1 knock-in model. Using these HA-Sumo mouse lines, we performed whole brain imaging and mapping to the Allen Brain Atlas to analyze the relative distribution of the Sumo1 and Sumo2 paralogues in the adult mouse brain. We observed differential staining patterns between Sumo1 and Sumo2, including a partial localization of Sumo2 in nerve cell synapses of the hippocampus. Combining immunoprecipitation with mass spectrometry, we identified native substrates targeted by Sumo1 or Sumo2 in the mouse brain. We validated select hits using proximity ligation assays, further providing insight into the subcellular distribution of neuronal Sumo2-conjugates. These mouse models thus serve as valuable tools to study the cellular and biochemical roles of SUMOylation in the central nervous system.

neuroscience↗

bioRxiv2022

Testis-specific H2BFWT disrupts nucleosome integrity through reductions of DNA-histone interactions

During spermatogenesis, multiple testis-specific histone variants are involved in the dynamic chromatin transitions. H2BFWT is a primate testis-specific H2B variant with hitherto unclear functions, and SNPs of H2BFWT are closely associated with male non-obstructive infertility. Here, we found that H2BFWT is preferentially localized in the sub-telomeric regions and the promoters of genes highly expressed in testis from differentiated spermatogonia to early spermatocytes. Cryo-EM structural analysis shows that H2BFWT nucleosomes are defined by weakened interactions between H2A-H2BFWT dimer and H4, and between histone octamer and DNA. Furthermore, one of its SNPs, H2BFWTH100R further destabilizes nucleosomes and increases the nucleosome unwrapping rate by interfering with the interaction with H4K91. Our results suggest that H2BFWT may be necessary for the regulation of spermatogenesis-related gene expression by decreasing transcriptional barriers, and that H2BFWTH100R overdrives its nucleosome-destabilizing effects which causes infertility.

biochemistry↗

bioRxiv2022

Computational Prediction of Synthetic Circuit Function Across Growth Conditions

A challenge in the design and construction of synthetic genetic circuits is that they will operate within biological systems that have noisy and changing parameter regimes that are largely unmeasurable. The outcome is that these circuits do not operate within design specifications or have a narrow operational envelope in which they can function. This behavior is often observed as a lack of reproducibility in function from day to day or lab to lab. Moreover, this narrow range of operating conditions does not promote reproducible circuit function in deployments where environmental conditions for the chassis are changing, as environmental changes can affect the parameter space in which the circuit is operating. Here we describe a computational method for assessing the robustness of circuit function across broad parameter regions. Previously designed circuits are assessed by this computational method and then circuit performance is measured across multiple growth conditions in budding yeast. The computational predictions are correlated with experimental findings, suggesting that the approach has predictive value for assessing the robustness of a circuit design.

synthetic biology↗

bioRxiv2022

Robustness and reproducibility of simple and complex synthetic logic circuit designs using a DBTL loop

Computational tools addressing various components of design-build-test-learn loops (DBTL) for the construction of synthetic genetic networks exist, but do not generally cover the entire DBTL loop. This manuscript introduces an end-to-end sequence of tools that together form a DBTL loop called DART (Design Assemble Round Trip). DART provides rational selection and refinement of genetic parts to construct and test a circuit. Computational support for experimental process, metadata management, standardized data collection, and reproducible data analysis is provided via the previously published Round Trip (RT) test-learn loop. The primary focus of this work is on the Design Assemble (DA) part of the tool chain, which improves on previous techniques by screening up to thousands of network topologies for robust performance using a novel robustness score derived from dynamical behavior based on circuit topology only. In addition, novel experimental support software is introduced for the assembly of genetic circuits. A complete design-through-analysis sequence is presented using several OR and NOR circuit designs, with and without structural redundancy, that are implemented in budding yeast. The execution of DART tested the predictions of the design tools, specifically with regard to robust and reproducible performance under different experimental conditions. The data analysis depended on a novel application of machine learning techniques to segment bimodal flow cytometry distributions. Evidence is presented that, in some cases, a more complex build may impart more robustness and reproducibility across experimental conditions.

synthetic biology↗

bioRxiv2022

Genome-wide association study of brain biochemical phenotypes reveals distinct genetic architecture of Alzheimer's Disease related proteins

Alzheimers disease (AD) is neuropathologically characterized by amyloid-beta (A{beta}) plaques and neurofibrillary tangles. Main protein components of these hallmarks include A{beta}40, A{beta}42, tau, phospho-tau and APOE. With the exception of the APOE-{varepsilon}4 variant, genetic risk factors associated with brain biochemical measures of these proteins have yet to be characterized. We performed a genome-wide association study in brains of 441 AD patients for quantitative levels of these proteins collected from three distinct fractions reflecting soluble, membrane-bound and insoluble biochemical states. We identified 123 genome-wide significant associations at seven novel loci and the APOE locus. Genes and variants at these loci also associate with multiple AD- related measures, regulate gene expression, have cell-type specific enrichment, and roles in brain health and other neuropsychiatric diseases. Pathway analysis identified significant enrichment of shared and distinct biological pathways. Although all biochemical measures tested reflect proteins core to AD pathology, our results strongly suggest that each have unique genetic architecture and biological pathways that influence their specific biochemical states in the brain. Our novel approach of deep brain biochemical endophenotype GWAS has implications for pathophysiology of proteostasis in AD that can guide therapeutic discovery efforts focused on these proteins.

genetics↗

bioRxiv2022

CITE-Viz: Replicating the Interactive Flow Cytometry Workflow in CITE-Seq

SummaryThe rapid advancement of new genomic sequencing technology has enabled the development of multi-omic single-cell sequencing assays. These assays profile multiple modalities in the same cell and can often yield new insights not revealed with a single modality. For example, CITE-Seq (Cellular Indexing of Transcriptomes and Epitopes by Sequencing) simultaneously profiles the single-cell RNA transcriptome and the surface protein expression. The extra dimension of surface protein markers can be used to further identify cell clusters - an essential step for downstream analyses and interpretation. Additionally, multi-dimensional datasets like CITE-Seq require nuanced visualization methods to accurately assess the data. To facilitate cell cluster classification and visualization in CITE-Seq, we developed CITE-Viz. CITE-Viz is a single-cell visualization platform with a custom module that replicates the interactive flow-cytometry gating workflow. With CITE-Viz, users can investigate CITE-Seq specific quality control (QC) metrics, view multi-omic co-expression feature plots, and classify cell clusters by iteratively gating on the abundance of cell surface markers. CITE-Viz was developed to make multi-modal single-cell analysis accessible to a wide variety of biologists, with the aim to discover new insights into their data and to facilitate novel hypothesis generation. Availability and ImplementationCITE-Viz installation and usage instructions can be found in the GitHub repository https://github.com/maxsonBraunLab/CITE-Viz Contactmaxsonj@ohsu.edu Supplementary InformationDown-sampled peripheral blood mononuclear dataset (Hao et al. 2021): https://bit.ly/3vxbhfW

bioinformatics↗