Biology subjects

Truong, P.

Publications and source records attributed to Truong, P..

7 recordsLinked to original sources

bioRxiv2026

Spatial immune profiling reveals lymphocyte confinement to myeloid-mesenchymal niches and heterogeneous therapeutic T-cell opportunity in pediatric ependymoma

Pediatric posterior fossa group A (PFA) ependymoma is an aggressive, chemo-resistant brain tumor with a poor 10-year overall survival and no therapeutic options at relapse. Although conventionally classified as immune-cold, the spatial organization and therapeutic relevance of its rare immune infiltrates remain poorly characterized. Here, we present a spatially resolved immune analysis of 14 PFA ependymoma sections using published Visium spatial transcriptomics data analyzed through a multi-stage immune-focused computational framework combining reference-guided deconvolution, functional lymphocyte state scoring, ligand-receptor inference, and {beta}/{gamma}{delta} T cell immunotherapy opportunity scoring. Lymphocyte-associated hotspots were identified in 6 of 14 sections and, among confidently classified hotspots, were dominated by inflammatory-associated and retention-associated transcriptional states rather than cytotoxic or exhausted programs. These hotspots were preferentially confined to myeloid- and mesenchymal-rich tumor zones with near-complete exclusion from epithelial regions; ligand-receptor analysis identified four candidate restriction axes (SPP1-CD44, FN1-integrin, collagen VI-integrin, and APP-CD74). Immunotherapy opportunity scoring revealed heterogeneous and spatially compartmentalized {beta} and {gamma}{delta} T cell recognition landscapes across sections: {beta}T ligand availability and immunosuppressive tone both rose in the mesenchymal compartment, while the two components of {gamma}{delta} phosphoantigen-mediated recognition were spatially and transcriptionally dissociated from one another. Together, these findings reframe PFA ependymoma not as a monolithic immune desert but as a tumor type with spatially compartmentalized, mechanistically tractable immune niches, and provide a generalizable computational strategy for mapping immune architecture and T cell therapy susceptibility in low-infiltrated pediatric CNS tumors.

cancer biology↗

bioRxiv2026

SCIMETAR-seq tracks immunophenotype, demethylation, mutations, and transcriptomes in single cells undergoing HMA therapy

5-azacytidine improves haematopoiesis and delays leukaemic progression in myelodysplastic neoplasms, but responses vary and are complicated by clonal mosaicism and heterogenous demethylation. Using a novel single-cell pipeline ("SCIMETAR-seq"), we found 5-azacytidine induced clonally distinct differentiation responses, with nuclear DNA demethylation occurring primarily in cycling progenitors. Despite the absence of significant nuclear DNA demethylation, quiescent stem cells underwent transcriptional remodelling in vivo, accompanied by 5-azacytidine-induced C*G-to-G*C mutations in mitochondria.

cancer biology↗

bioRxiv2026

Transcriptomic Profiling of Thyroid Eye Disease Orbital Fibroblasts Identifies Sorafenib as a Novel Therapeutic

Thyroid eye disease (TED) is a debilitating condition characterized by orbital fibroblast (OF) activation and excessive hyaluronic acid (HA) accumulation within the retro-ocular space. While IGF-1R blockade with teprotumumab has significantly advanced TED management, incomplete clinical responses and disease relapse underscore the need to identify alternative targets. In this study, we used high-throughput RNA sequencing to map the transcriptomic landscape in TED OFs compared with non-TED OF controls. Our analysis identified robust enrichment of pathways critical to the TED phenotype, including PI3K-AKT signaling, the platelet-derived growth factor (PDGF) pathway, and extracellular matrix remodeling. We validated several key upregulated mediators that may contribute to orbital remodeling, including FOXC2, HGF, MET, and HMGA2, alongside the downregulation of the Wnt antagonist SFRP2. By employing a computational drug-repositioning approach, we identified the multi-kinase inhibitor sorafenib, which targets VEGFR, PDGFR, and RAF, as a potent candidate to neutralize the TED-specific gene signature. Functional assays demonstrated that sorafenib dose-dependently inhibited PDGF-induced AKT phosphorylation and significantly attenuated HA synthesis in primary TED OFs. These results define a persistent, receptor tyrosine kinase-driven program in the TED orbit and suggest that multi-kinase inhibition represents a viable therapeutic strategy for refractory TED. HighlightsO_LIThyroid eye disease (TED) orbital fibroblasts exhibit a transcriptomic signature characterized by elevated PI3K/AKT, angiogenic, and growth factor signaling. C_LIO_LIComputational drug prediction identifies sorafenib as a candidate to reverse the TED gene signature. C_LIO_LISorafenib dose-dependently inhibits AKT activation and hyaluronic acid production in TED orbital fibroblasts. C_LI

molecular biology↗

bioRxiv2025

difFUBAR: Scalable Bayesian comparison of adaptive evolution

While many phylogenetic methods exist to characterize evolutionary pressure at individual codon sites, relatively few allow direct comparison between different a priori selected sets of branches. Such comparisons may be useful for pinpointing precisely the codon sites that are under differing selective pressures due to differing environmental contexts, or differing genomic contexts via epistatic interactions. Indeed, this was only recently addressed by an approach, developed in the frequentist framework, that proposes a site-wise likelihood ratio hypothesis test. Previously, we have demonstrated that approximate grid-based Bayesian approaches to characterizing site-wise variation in selection parameters can outperform individual site-wise likelihood ratio tests. Such grid-based approaches can exhibit poor computational scaling when the number of site-wise parameters expands, but here we show that this is still tractable up to four parameters, and that a simple subtree-likelihood caching strategy can provide efficiency improvements in some cases. We propose difFUBAR, which allows the demarcation of two branch sets of interest and, optionally, a background set, and estimates joint site-specific posterior distributions over , {omega}1,{omega} 2, and{omega} BG using a Gibbs sampler. Evidence for hypotheses of interest can then be quantified directly from the posterior distribution, and we standardly report P ({omega}1 > {omega}2), P ({omega}2 > {omega}1), P ({omega}1 > 1), and P ({omega}2 > 1). We characterize the computational and statistical performance of this approach on previous simulations, comparing it to the site-wise likelihood ratio test approach, where it shows moderate statistical benefits, and substantial computational gains, typically being more than two orders of magnitude faster on the same datasets. We also demonstrate that it can scale to datasets of over ten thousand taxa, on a laptop in under ten minutes. difFUBAR is implemented in MolecularEvolution.jl - a Julia framework for phylogenetic model development - and can be run locally, or online via a Colab notebook.

bioinformatics↗

bioRxiv2024

Genome-Wide CRISPR-Cas9 Screening Identifies a Synergy between Hypomethylating Agents and SUMOylation Blockade in MDS/AML

Hypomethylating agents (HMAs) are frontline therapies effective at altering the natural course of Myelodysplastic Neoplasms (MDS) and Acute Myeloid Leukemia (AML). However, acquired resistance and treatment failure are hallmarks of HMA therapy. To address this clinical need, we performed a genome-wide CRISPR-Cas9 screen in a human MDS-derived cell line, MDS-L, and identified TOPORS as a highly ranked loss-of-function target that synergizes with HMAs, reducing leukemic burden and improving survival in xenograft models. We demonstrate that the depletion of TOPORS mediates sensitivity to HMAs by predisposing leukemic blasts to an impaired DNA damage response (DDR) accompanied by an accumulation of SUMOylated DNMT1 in HMA-treated TOPORS-depleted cells. Importantly, the combination of HMAs with targeting of TOPORS did not functionally impair healthy hematopoiesis. While inhibitors of TOPORS are currently unavailable, we show that inhibition of protein SUMOylation (upstream of TOPORS functions) with TAK-981 partially phenocopies HMA-sensitivity and DDR impairment. Overall, our data suggest that the combination of HMAs with the inhibition of SUMOylation or TOPORS demonstrates a favourable therapeutic index and is a rational treatment framework for High-Risk MDS (HR-MDS) or AML.

molecular biology↗

bioRxiv2020

Depth relationships and measures of tissue thickness in dorsal midbrain

Dorsal human midbrain contains two nuclei with clear laminar organization, the superior and inferior colliculi. These nuclei extend in depth between the superficial dorsal surface of midbrain and a deep midbrain nucleus, the periaqueductal gray matter (PAG). The PAG, in turn, surrounds the cerebral aqueduct (CA). This study examined the use of two depth metrics to characterize depth and thickness relationships within dorsal midbrain using the superficial surface of midbrain and CA as references. The first utilized nearest-neighbor Euclidean distance from one reference surface, while the second used a level-set approach that combines signed distance from both reference surfaces. Both depth methods provided similar functional depth profiles generated by saccadic eye movements in a functional MRI task, confirming their efficacy for superficial functional activity. Next, the boundaries of the PAG were estimated using Euclidean distance together with elliptical fitting, indicating that the PAG can be readily characterized by a smooth surface surrounding PAG. Finally, we used the level-set approach to measure tissue depth between the superficial surface and the PAG, thus characterizing the variable thickness of the colliculi. Overall, this study demonstrates depth-mapping schemes for human midbrain that enables accurate segmentation of the PAG and consistent depth and thickness estimates of the superior and inferior colliculi.

neuroscience↗

bioRxiv2020

An unsupervised algorithm for host identification in flaviviruses

Early characterization is essential to control the spread of emerging viruses, such as the Zika Virus outbreak in 2014. A major challenge is the identification of potential hosts for novel viruses. We introduce an algorithm to identify the host range of a virus from its raw genome sequence that will be a useful tool to understand host-virus relationships.

bioinformatics↗