Biology subjects

Nguyen, A.

Publications and source records attributed to Nguyen, A..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Crystal structures of forty- and seventy-one-substitution variants of hydroxynitrile lyase from rubber tree

The /{beta}-hydrolase fold family contains mostly esterases but includes other enzymes such as hydroxynitrile lyase from Hevea brasiliensis (rubber tree, HbHNL). HbHNL shares 44% sequence identity and a Ser-His-Asp catalytic triad with esterase SABP2 (salicylic acid binding protein 2 from Nicotiana tabacum (tobacco)). To identify how large a region within HbHNL influences the positions of the catalytic residues, we created variants where increasingly large regions surrounding the substrate-binding site had identical amino acid sequences to those in SABP2. Variant HNL40 contains 40 mutations (two inserted amino acid residues, 38 substitutions), shares 59% sequence identity with SABP2, and is identical in sequence to SABP2 within 10 [A] of the substrate-binding site. Variant HNL71 contains 31 additional substitutions for a total of 71 changes (two insertions, 69 substitutions) and shares 71% sequence identity with SABP2. The sequences within 14 [A] of the substrate-binding site are identical in SABP2 and HNL71. The crystal structures of HNL40 and HNL71 show that the positions of main chain C[a] atoms move from their positions in HbHNL to more closely match those in SABP2 (RMSD = 0.51 [A] over 235 C[a] atoms for HNL40, 0.41 [A] over 219 C[a] atoms for HNL71) and even more closely in the region within 10 [A] of the substrate-binding site (RMSD = 0.38 [A] over 58 C[a] atoms for HNL40, 0.28 [A] over 53 C[a] atoms for HNL71). The pattern of tunnels in HNL40 and HNL71 are similar to each other and intermediate between the pattern in HbHNL and SABP2. SynopsisVariants HNL40 and HNL71 of hydroxynitrile lyase from Hevea brasiliensis contain 40 and 71 mutations, respectively, to make regions surrounding the substrate-binding site identical in sequence to esterase SABP2. X-ray structures reveal increasing similarities to SABP2 in HNL40 and HNL71. PDB reference: hydroxynitrile lyase from Hevea brasiliensis with forty mutations, 8SNI, hydroxynitrile lyase from Hevea brasiliensis with seventy-one mutations, 9CLR

biochemistry↗

bioRxiv2025

Stochastically Emergent Tumors offer in vivo whole genome interrogation of cancer evolution from non-malignant precursors

Interrogating the stochastic events underlying tumor evolution from non-malignant precursors is crucial for understanding therapy resistance. Current methods are complicated by chromosomal instability, obscuring driver identification and yielding non-representative genetics. Inspired by patient tumors that evolve without chromosomal instability, we developed Stochastically Emergent Tumors (SETs) by inducing mismatch repair deficiency in non-malignant precursors, then engrafting in mice. Barcoded SETs exhibited increased tumoral and drug target heterogeneity over current models. SETs delineated the stochastic contributions, mutational landscapes, and selective pressures distinguishing tumorigenesis from non-malignant precursor in vitro growth. SETs are an unlimited source for diverse Stochastically Emergent cell Lines (SELs), bolstering under-represented cancers. Since SETs composition dynamically reflects therapy exposure, they are a whole-genome platform for precision oncology. We identified three novel genetic drivers (ZFHX3, CIC, KMT2D) of differential prostate cancer therapy responses. These alterations are enriched in patients of African and Chinese ancestry and correlate with significant differences in survival.

cancer biology↗

bioRxiv2025

Octopamine regulates neural circuits in the mushroom body and central complex, influencing sleep and context-dependent arousal.

Sleep is a complex and ubiquitous phenomenon in the animal kingdom, yet the mechanisms, modes, and effects of sleep on the brain and body remain highly variable and not fully understood. While sleep and wakefulness are often measured as two binary states at the behavioral level, animals exhibit a wide range of arousal states during wakefulness. Behaviors such as feeding, courting, escaping predators, or avoiding unfavorable environments are critical for survival and often compete with sleep. Biogenic amines, including dopamine, norepinephrine, and serotonin, are known to regulate sleep and arousal behaviors across species, offering valuable insights into how these states are co-regulated. In this study, we leverage the small number, discrete organization, and well-defined connectivity patterns of neuromodulatory neurons in the fly brain to investigate how specific octopamine (OA) neurons regulate sleep and context-dependent arousal. We focus on a pair of OA neurons, VPM3, which project extensively to the mushroom body (MB) and central complex (CX). Our findings reveal that VPM3 neurons are sexually monomorphic and that their activity is essential for sleep suppression and male courtship behavior. Furthermore, we demonstrate that the male-specific form of the fruitless gene in these neurons plays a critical role in sleep regulation and that their activity is influenced by sleep history. Using connectome data and highly specific genetic tools, we identify upstream inputs to VPM3 neurons from the CX and elucidate the downstream pathways mediated by the MB, as well as the role of specific OA receptors. These detailed investigations highlight the multifaceted role of octopamine in sleep suppression and context-specific arousal, providing a crucial link between identified sleep microcircuits in the mushroom body and central complex.

neuroscience↗

bioRxiv2025

Viscoelastic HyA Hydrogel Promotes Recovery of Muscle Quality and Vascularization in a Murine Model of Delayed Rotator Cuff Repair

Rotator cuff tears are among the most common musculotendinous injuries with high risk of permanent functional disability. Following surgical repair, sub-optimal patient outcomes are directly correlated with poor muscle quality; namely, injury site fatty infiltration (FI), fibrosis, and muscle atrophy. Muscle resident fibro-adipogenic progenitor cells (FAPs) have been identified as key regulators of post-injury skeletal muscle regeneration and repair by maintaining a promyogenic environment. In this work, human-derived FAPs (hFAPs) were encapsulated into hyaluronic acid (HyA)-based hydrogels functionalized with bsp-RGD(15) cell adhesion peptide, heparin, and a matrix metalloproteinase (MMP)-cleavable crosslinker. Hydrogel-encapsulated hFAPs increased expression of the promyogenic marker UCP1 and production of the anti-inflammatory cytokine IL-10, while downregulating the expression of the fibrotic marker SMA over time. A murine model of unilateral rotator cuff transection, denervation, and delayed repair was treated with the HyA hydrogel or PBS and compared to a contralateral, non-injured control limb. Muscle histology 6 weeks post-repair revealed that the hydrogel reduced fibrosis, FI, and muscle atrophy while supporting vascularization of the injured tissue region. Collectively, these results suggest that the hydrogel alone can promote muscle regeneration in a clinically relevant delayed repair model of rotator cuff tear, which we hypothesize is due to controlled FAP differentiation into promyogenic lineages.

bioengineering↗

bioRxiv2025

Structural and functional characterization of integrin a5-targeting antibodies for anti-angiogenic therapy

Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin 5{beta}1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and metastasis. Despite numerous efforts, 5{beta}1-targeting therapeutics have been unsuccessful due to poor efficacy and off-target effects. A contributing factor is our limited understanding of how integrin conformation influences interactions with therapeutics. Using cell-based functional assays, patient-derived xenografts, biophysics, and electron microscopy, we shed light on these relationships by characterizing two anti-5{beta}1 antibodies, BIIG2 and MINT1526A. We show that both antibodies bind 5{beta}1 with nanomolar affinity, reduce tube formation in vitro, and bind overlapping epitopes that block fibronectin binding. However, using electron microscopy, we reveal that while BIIG2 binding does not substantially alter the conformational states, MINT1526A preferentially recognizes the bent conformation and restricts the conformational ensemble. These insights can guide which aspects to prioritize to improve the design of future integrin-targeted therapeutics.

biochemistry↗

bioRxiv2024

Targeting de novo lipogenesis improves gemcitabine efficacy in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with few treatment options and poor survivability. In this work we sought to characterise metabolic adaptations to gemcitabine (GEMC)-based chemotherapy exposure to discover new therapeutic targets for improving treatment efficacy. We show that GEMC resistance (GEMR) upregulates de novo lipogenesis in Panc1 and MiaPaCa2 cells through increased activity and expression of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1). We also discovered alternate fatty acid desaturase 2 (FADS2) activity in Panc1 cells, which led to the production of sapienic acid (FA 16:1n-10, cis) from palmitic acid (FA 16:0). Knockdown of key lipid synthesis enzymes sensitised cells to GEMC treatment, with FAS (both cell lines), SCD1 (MiaPaCa2 only) and SCD1+FADS2 (Panc1) knockdown showing the greatest reduction in cell growth when combined with GEMC treatment. In Panc1 cells, both desaturases upregulated their activity when the alternate was knocked down, necessitating the need for dual desaturase knockdown in this cell line. PDAC cells attenuated to grow in combination GEMC/paclitaxel (CombAT) also displayed enhanced de novo lipogenesis; however, combination chemotherapy significantly downregulated FADS2 expression and activity in Panc1 CombAT cells rendering them more sensitive to SCD1 knockdown. We conclude that co-targeting lipid synthesis in PDAC could be a viable strategy for improving the efficacy of both GEMC monotherapy and combination GEMC/PTX therapy.

cancer biology↗

bioRxiv2024

Benchmarking concentration and direct extraction methods for wastewater-based surveillance of eight human respiratory viruses: implications for rapid application to novel pathogens

Wastewater monitoring is rapidly expanding to provide surveillance for a growing number of epidemic and endemic pathogens. To provide early warning and support rapid response to a novel virus through wastewater surveillance, it would be ideal to understand in advance which concentration and extraction methods are likely to be effective for dPCR-based methods, depending on virus characteristics. In this study, we spiked wastewater samples with eight human respiratory viruses and processed them with four commercial methods that concentrate and/or extract nucleic acids from both liquid and solid fractions (Promega, Nanotrap, InnovaPrep), or only the solid fraction of wastewater (Solids). Our findings provide encouraging evidence that all four concentration/extraction methods combined with dPCR could detect an emerging virus in wastewater, although they differed in sensitivity. The pattern of recovery efficiency for adenoviruses, coronaviruses, and influenza A viruses was consistent across methods, while distinct patterns were observed for coxsackieviruses. Promega produced higher median recovery efficiencies based on dPCR for all viruses except for coxsackieviruses, even though it had the highest dPCR inhibition. We suggest caution in applying Nanotrap to new targets, based on the low recovery of coxsackievirus B5 compared to the other viruses. We also quantified the endogenous indicators PMMoV and Carjivirus (formerly crAssphage), illustrating how normalization could either improve or worsen the comparison of virus concentrations measured by different methods. These findings can guide the selection of concentration and extraction methods for wastewater monitoring based on the properties of target viruses, thus enhancing pandemic preparedness. Synopsis StatementBenchmarking scalable concentration and extraction methods on respiratory viruses with diverse properties facilitates the rapid application of wastewater-based surveillance to emerging viruses.

microbiology↗

bioRxiv2024

Inhibition of serine and arginine-rich splicing factor 3 induces epidermal differentiation and decreases cutaneous squamous cell carcinoma risk

Serine/Arginine-rich splicing factor 3 (SRSF3) is one of 12 SRSFs that regulate gene expression via alternative splicing. SRSF3 is upregulated in cutaneous squamous cell carcinoma (cSCC) and several squamous cancer cell lines in relation to normal keratinocytes. We suppressed SRSF3 with a specific inhibitor, SFI003, and observed an increase in epidermal differentiation. Our data suggests that in cSCC, SRSF3 overexpression suppresses cellular differentiation to enable cancer progression. In a clinical setting, patients taking known SRSF3 inhibitors digoxin and amiodarone exhibited higher cSCC-free survival compared to a propensity score-matched cohort treated with beta blockers. Thus, SRSF3 upregulation may be a novel therapeutic target in cSCC that can improve patient prognoses.

cancer biology↗

bioRxiv2024

Complex system modelling reveals oxalate homeostasis is driven by diverse oxalate-degrading bacteria

Decades of research have made clear that host-associated microbiomes touch all facets of health. However, effective therapies that target the microbiome have been elusive given its inherent complexity. Here, we experimentally examined diet-microbe-host interactions through a complex systems framework, centered on dietary oxalate. Using multiple, independent molecular, animal, and in vitro experimental models, we found that microbiome composition influenced multiple oxalate-microbe-host interfaces. Importantly, administration of the oxalate-degrading specialist, Oxalobacter formigenes, was only effective against a poor oxalate-degrading microbiota background and gives critical new insights into why clinical intervention trials with this species exhibit variable outcomes. Data suggest that, while heterogeneity in the microbiome impacts multiple diet-host-microbe interfaces, metabolic redundancy among diverse microorganisms in specific diet-microbe axes is a critical variable that may impact the efficacy of bacteriotherapies, which can help guide patient and probiotic selection criteria in probiotic clinical trials.

microbiology↗

bioRxiv2024

Sounds and Sights in Sequence Learning: Can Accessory Auditory Cues Enhance Motor Task Performance?

Motor sequence learning, or the ability to learn and remember sequences of actions, such as the sequence of actions required to tie ones shoelaces, is ubiquitous to everyday life. Contemporary research on motor sequence learning has been largely unimodal, ignoring the possibility that our nervous system might benefit from sensory inputs from multiple modalities. In this study, we investigated the properties of motor sequence learning in response to auditory-visual stimuli. We found that sequence learning with auditory-visual stimuli showed a hallmark feature of traditional unimodal sequence learning tasks: sensitivity to stimulus timing, where lengthier interstimulus intervals of 500 ms improved sequence learning compared to briefer interstimulus intervals of 200 ms. Consistent with previous findings, we also found that auditory-visual stimuli improved learning compared to a unimodal visual-only condition. Furthermore, the informativeness of the auditory stimuli was important, as auditory stimuli which predicted the location of visual cues improved sequence learning compared to uninformative auditory stimuli which did not predict the location of the visual cues. Our findings suggest a potential utility of leveraging audio-visual stimuli in sequence learning interventions to enhance skill acquisition in education and rehabilitation contexts.

neuroscience↗

bioRxiv2024

Fundamental trade-offs in the robustness of biological systems with feedback regulation

Natural biological systems use a complex network of feedback regulation to effectively respond to their changing environment. Even though in engineered systems we understand how accurate feedback can be depending on the electronic or mechanical parts that it is implemented with, we largely lack a similar theoretical framework to study biological feedback. Specifically, it is not fully understood or quantified how accurate or robust the implementation of biological feedback actually is. In this paper, we study the sensitivity of biological feedback to variations in biochemical parameters using five example circuits: positive autoregulation, negative autoregulation, double-positive feedback, positive-negative feedback and double-negative feedback (the toggle switch). We find that of these examples of biological feedback are subjected to fundamental trade-offs, and we propose multi-objective optimisation as a framework to study them. The impact of this work is to improve robust circuit design for synthetic biology and to improve our understanding of systems biology.

synthetic biology↗

bioRxiv2024

Cholesterol binding to VCAM-1 promotes vascular inflammation

Hypercholesterolemia has long been implicated in endothelial cell (EC) dysfunction, but the mechanisms by which excess cholesterol causes vascular pathology are incompletely understood. Here we used a cholesterol-mimetic probe to map cholesterol-protein interactions in primary human ECs and discovered that cholesterol binds to and stabilizes the adhesion molecule VCAM-1. We show that accessible plasma membrane (PM) cholesterol in ECs is acutely responsive to inflammatory stimuli and that the nonvesicular cholesterol transporter Aster-A regulates VCAM-1 stability in activated ECs by controlling the size of this pool. Deletion of Aster-A in ECs increases VCAM-1 protein, promotes immune cell recruitment to vessels, and impairs pulmonary immune homeostasis. Conversely, depleting cholesterol from the endothelium in vivo dampens VCAM-1 induction in response to inflammatory stimuli. These findings identify cholesterol binding to VCAM-1 as a key step during EC activation and provide a biochemical explanation for the ability of excess membrane cholesterol to promote immune cell recruitment to the endothelium.

physiology↗

bioRxiv2024

Evaluating Best Practices for Isolating Pyrophilous Bacteria and Fungi from Burned Soil

A live microbial culture is invaluable to assess traits and functions, yet culturing immediately from fresh soil is logistically challenging and media selection is not trivial. Deeper ecological understanding of pyrophilous microbes and their traits is hampered by a lack of culture-based work causing researchers to rely heavily on community sequence analysis. To improve our understanding of isolating pyrophilous bacteria and fungi after wildfires from burned soil, we tested which: 1) soil storage method and 2) media retained highest genera richness and highest culturable viability as measured by CFUs retained. We tested four soil storage methods (dried, refrigerated at 4{degrees}C, stored at -80{degrees}C with or without glycerol) using a well-homogenized soil sample, plated microbes on rich media, and compared to fresh soil obtained 6 months after a severe California shrubland wildfire. From the fresh soils, we tested 3 media types: rich (Lysogeny Broth (LB) for bacteria; Malt Yeast Agar (MYA) for fungi), oligotrophic (Reasoners 2 Agar (R2A)) and media made from pyrogenic organic matter (PyOM). For bacteria, storing soil frozen at -80{degrees}C without glycerol yielded the highest genera richness and with glycerol preserved the most species. For fungi, storing soil at -80{degrees}C without glycerol preserved the most species but preserved equivalent richness of genera as fresh and 4{degrees}C soil. R2A yielded the highest bacterial and fungal genus richness but some species of interest were only captured with PyOM. Using a combination of these storage and media methods along with a few additional techniques (mushroom cultivation, smoke cultivation, etc.) from 2018-2022, we cultured >500 isolates (286 bacteria; 258 fungi) after 7 California wildfires for testing pyrophilous microbial traits. ImportanceFires are increasing in frequency and severity across the globe, making the understanding of the traits of the pyrophilous microbes that survive and thrive post-fire and influence post-fire ecosystem regeneration critical and pressing. Yet, our ability to characterize the traits of pyrophilous microbes through genomics, transcriptomics, and phenotypic assays is hampered by lack of organisms in culture. Here, we debut a new medium created from pyrogenic organic matter that helps to cultivate fastidious pyrophilous microbes, and also describe a large-scale culture collection of pyrophilous bacteria and fungi (>500 isolates) that can be used for future collaborative research. We comprehensively test how soil storage and media type affect the cultivation of both bacteria and fungi, and for the first time, we test the best method to store soil to retain fungal diversity. Our work can be applied to improve culture collections of fastidious microbes from a variety of environments.

microbiology↗

bioRxiv2024

Divergent response to radio-immunotherapy is defined by intrinsic features of the tumor microenvironment

BackgroundTreatment with immunotherapy can elicit varying responses across cancer types, and the mechanistic underpinnings that contribute to response vs. progression remain poorly understood. However, to date there are few preclinical models that accurately represent these disparate disease scenarios. MethodsUsing combinatorial radio-immunotherapy consisting of PD-1 blockade, IL2R{beta}{gamma} biased signaling, and OX40 agonism we were able to generate preclinical tumor models with conflicting responses, where head and neck squamous cell carcinoma (HNSCC) models responds and pancreatic ductal adenocarcinoma (PDAC) progresses. ResultsBy modeling these disparate states, we find that regulatory T cells (Tregs) are expanded in PDAC tumors undergoing treatment, constraining tumor reactive CD8 T cell activity. Consequently, the depletion of Tregs restores the therapeutic efficacy of our treatment and abrogates the disparity between models. Moreover, we show that through heterotopic implantations that the site of tumor development defines the response to therapy, as implantation of HNSCC tumors into the pancreas resulted in comparable levels of tumor progression. ConclusionsThis work highlights complexity of combining immunotherapies within the tumor microenvironment and further defines the immune and non-immune components of the tumor microenvironment as an intrinsic feature of immune suppression. What is already known on this topicO_LIIn Head and neck squamous cell carcinomas (HNSCC) and pancreatic ductal adenocarcinoma (PDAC), targeting PD-1 and IL2R{beta}{gamma} simultaneously (PD1-IL2v) has been shown to be effective when combined with radiation therapy (RT), yet complete response is still limited. The T cell co-stimulatory receptor OX40 (TNFRSF4) has pleiotropic effects, promoting T cell survival, expansion, and memory differentiation in conventional effector T cells, while subsequently limiting regulatory T cell (Treg) suppression by constraining induction and expression of Foxp3. Expression of OX40 is highly upregulated after treatment with PD1-IL2v, and we postulated that combining OX40 agonism with PD1-IL2v and RT would provide additional benefit. C_LI What this study addsO_LIUsing orthotopic models of HNSCC and PDAC, we found that the addition of OX40 agonism unexpectedly drives tumor progression in PDAC, but not HNSCC. Intriguingly, this effect dependent on the tumor microenvironment as the effect is reversed by swapping the location of tumor implantation. This progression was also abrogated by the depletion of regulatory T cells (Tregs), a known mediator of resistance in these models. C_LI How this study might affect research, practice or policyO_LIOur data demonstrate that unexpected and deleterious effects can stem from combining multiple immunotherapies. These findings hold particular translational relevance as the use of combination immunotherapies is increasingly common on trial. C_LI

immunology↗

bioRxiv2024

EEG source imaging technique to investigate sleep oscillations for simultaneous EEG-fMRI

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a widely used non-invasive neuroimaging technique in sleep studies. However, EEG data are strongly influenced by two types of MRI-related artefacts: gradient artefacts (GA) and ballistocardiogram artefacts (BCG). If artefacts correction is suboptimal, the BCG obscures the EEG signals below 20Hz and could make it difficult to investigate sleep oscillations, especially sleep spindles, sleep specific oscillations occurring within 11-16Hz frequency band. We previously demonstrated the utility of beamforming spatial filtering in correcting MRI-related artefacts on EEG. Here, we investigated the use of beamforming spatial filtering for improving the detection of EEG oscillations during sleep, in particular, 1) to accurately estimate single-event spindle EEG power changes, and 2) to demonstrate the potential improvement of fMRI general linear model (GLM) analysis when involving such additional EEG information. We analysed EEG-fMRI data acquired during a recovery nap after sleep deprivation in 20 young healthy participants (12 females, 8 males, age = 21.3 {+/-} 2.5 years). Based on spindle events (onset and duration) detected by trained sleep scorers on BCG corrected EEG signals through a conventional average artefact subtraction (AAS) method, we compared four different EEG processing steps: non-BCG corrected; AAS BCG corrected; beamforming BCG corrected; beamforming+AAS BCG corrected. These processing steps consist of non-BCG corrected and AAS BCG corrected considered either at the sensor level or at the source-level (after beamformer localization) to evaluate the impact of the BCG artefact on the detection of spindle activity. Then we further investigated four different fMRI GLM approaches using 1) the spindle onset and duration (GLM1), 2) spindle onset, duration, and parametric modulation of single-spindle power change from the Cz electrode of the AAS BCG corrected data (GLM2), 3) spindle onset, duration, and parametric modulation of single-spindle power change from the beamforming+AAS BCG corrected (GLM3) and 4) spindle onset, duration, and parametric modulation of single-spindle power change from the beamforming BCG corrected data (GLM4). We found that the beamforming approach did not only attenuate the BCG artefacts, but also recovered sleep spindle activity occurring during NREM sleep. Furthermore, this beamforming approach allowed us to accurately estimate single-event power change of each spindle in the source space when compared to the channel level analysis, and therefore to further improve the specificity of fMRI GLM analysis, better localizing the recruited brain regions during spindles. Our findings show the benefit of applying beamforming source imaging technique to EEG-fMRI acquired during sleep. We demonstrate that this approach would be beneficial especially for long EEG-fMRI data acquisitions (i.e., sleep, resting-state), when the BCG correction becomes problematic due to inherent dynamic changes of heart rates. Our findings extend previous work regarding the application of the source imaging to the sleep EEG-fMRI. Combining with this advanced methodology and analysis, sleep EEG-fMRI will help us better understand the functional roles of human sleep.

neuroscience↗

bioRxiv2024

Manipulating the EphB4-ephrinB2 axis to reduce metastasis in HSNCC

The EphB4-ephrinB2 signaling axis has been heavily implicated in metastasis across numerous cancer types. Our emerging understanding of the dichotomous roles that EphB4 and ephrinB2 play in head and neck squamous cell carcinoma (HNSCC) poses a significant challenge to rational drug design. We find that EphB4 knockdown in cancer cells enhances metastasis in preclinical HNSCC models by augmenting immunosuppressive cells like T regulatory cells (Tregs) within the tumor microenvironment. EphB4 inhibition in cancer cells also amplifies their ability to metastasize through increased expression of genes associated with epithelial mesenchymal transition and hallmark pathways of metastasis. In contrast, vascular ephrinB2 knockout coupled with radiation therapy (RT) enhances anti-tumor immunity, reduces Treg accumulation into the tumor, and decreases metastasis. Notably, targeting the EphB4-ephrinB2 signaling axis with the engineered EphB4 ligands EFNB2-Fc-His and Fc-TNYL-RAW-GS reduces local tumor growth and distant metastasis in a preclinical model of HNSCC. Our data suggest that targeted inhibition of vascular ephrinB2 while avoiding inhibition of EphB4 in cancer cells could be a promising strategy to mitigate HNSCC metastasis.

cancer biology↗

bioRxiv2024

Bona fide cytotoxic iNKT cells with superior antitumour responses identified in mice and humans

Adoptive cell therapies (ACT) using unmodified or engineered invariant Natural Killer T (iNKT) cells are in clinical trials for cancer treatment. While promising, outcomes are still suboptimal, possibly due to iNKT cell heterogeneity. This study identified unique iNKT cell populations with strong cytotoxic activity in mice and humans. In mice, iNKT1c cells showed potent CD1d-dependent and -independent antitumor functions, with responses influenced by NK receptors. IL-15 enhances their cytolytic activity, while retinoic acid is essential for their generation. In humans, terminally differentiated CD57+ iNKT cells showed marked NK-receptor expression and most effectively killed C1R tumor cells in vitro. These cells appeared activated/exhausted within tumors of non-small cell lung cancer patients. Additionally, a central memory-like CD62L+ CD4- iNKT subset efficiently expanded and generated cytotoxic CD57+ iNKT cells in vitro, making them an appealing candidate for ACT. This study paves the way for the design of more effective iNKT cell-based immunotherapies.

immunology↗

bioRxiv2024

Global Phylogeography and Microdiversity of the Marine Diazotrophic Cyanobacteria Trichodesmium and UCYN-A

Cyanobacterial diazotrophs, specifically the genera Trichodesmium and UCYN-A, play a pivotal role in marine nitrogen cycling through their capacity for nitrogen fixation. Despite their global distribution, the microdiversity and environmental drivers of these diazotrophs remain underexplored. This study provides a comprehensive analysis of the global diversity and distribution of Trichodesmium and UCYN-A using the nitrogenase gene (nifH) as a genetic marker. We sequenced 954 samples from the Pacific, Atlantic, and Indian Oceans as part of the Bio-GO-SHIP project. Our results reveal significant phylogenetic and biogeographic differences between and within the two genera. Trichodesmium exhibited greater microdiversity compared to UCYN-A, with clades showing region-specific distribution. Trichodesmium clades were primarily influenced by temperature and nutrient availability, and particularly frequent in regions of phosphorus stress. In contrast UCYN-A was found in regions of iron stress. UCYN-A clades demonstrated a more homogeneous distributions, with a single sequencing variant within the UCYN-A1 clade dominating across varied environments. The biogeographic patterns and environmental correlations of Trichodesmium and UCYN-A highlight the role of microdiversity in their ecological adaptation and reflect their different ecological strategies. This study underscores the importance of characterizing the global patterns of fine-scale genetic diversity to better understand the functional roles and distribution of marine nitrogen-fixing cyanobacteria.

microbiology↗