Biology subjects

Ngo, G.

Publications and source records attributed to Ngo, G..

7 recordsLinked to original sources

bioRxiv2025

Adenovirus-based vaccines transduce and activate human Langerhans cells

Langerhans cells (LCs) are specialized antigen-presenting cells (APCs) located in the epidermis and mucosal tissues and play a critical role in host immune surveillance. The role of LCs in antiviral responses is well established, but their involvement in vaccine-induced immunity, particularly with human adenovirus (HAdV) vectors, remains poorly understood. Here, we investigated how human LCs respond to HAdV vectors commonly used in vaccine development. We used CD34+ hematopoietic stem cells differentiated into LCs (CD34-LCs) to evaluate their ability to internalize replication-defective HAdV types C5, D26, and B35 vectors. CD34-LCs took up all three vectors, which induced an antiviral and pro-inflammatory cytokine response and morphological changes indicative of activation. To address the role of LCs in a more physiologically relevant setting, we injected human skin explants with the HAdV vectors. Epidermal LCs were recruited to the injection site and took up the vectors. Moreover, we show that the presence of lactoferrin (Lf), an antimicrobial protein, enhances HAdV uptake. Overall, our findings highlight a key role for LCs in the initiation of immune responses to HAdV-based vaccines. This work lays a foundation for strategies aiming to enhance vaccine efficacy by modulating LC activation and targeting. IMPORTANCEHAdV vectors are widely used in vaccine development, but the role of LCs, the epidermal immune sentinels, remains poorly defined. Here, we show using in vitro and ex vivo human systems that LCs efficiently detect, internalize and express transgenes delivered by three HAdV species. Because LCs link innate and adaptive immunity, the direct and indirect uptake of HAdVs may contribute to vaccine efficacy.

immunology↗

bioRxiv2025

Childhood brain tumours instruct cranial haematopoiesis and immunotolerance

Recent research has revealed a remarkable role for immunosurveillance in healthy and diseased brains, dispelling the notion that this organ is a passive immune-privileged site1-3. Better understanding of how this immunosurveillance operates could improve the treatment of neurological diseases. Here, using a novel genetically engineered mouse model of ZFTA-RELA ependymoma4-a childhood brain tumour-we characterised an immune circuit between the tumour and antigen presenting, haematopoietic stem/progenitor cells (HSPCs) in the skull bone marrow. The presentation of antigens in the cerebrospinal fluid (CSF) by HSPCs to CD4+ T cells, biased HSPC lineages toward myelopoiesis and polarised CD4+ T-cells to regulatory T cells (T- regs), culminating in tumour immunotolerance. Remarkably, a single infusion of antibodies directed against cytokines enriched in the CSF of mice bearing ZFTA-RELA ependymomas, choroid plexus carcinomas or Group-3 medulloblastoma-all aggressive childhood brain tumours-disrupted this process and caused profound tumour regression. These data unmask a mechanism by which skull bone marrow-derived HSPCs and CD4+ T cells cooperate to promote the immunotolerance of childhood brain tumours. Antibodies that disrupt this immunosurveillance could prove an effective therapy for these cancers that are less toxic than current treatments.

immunology↗

bioRxiv2025

CF2H: a Cell-Free Two-Hybrid platform for rapid protein binder screening

Protein binders that detect, activate, inhibit or otherwise modulate their targets are pivotal for biomedical applications. With the increasing accuracy and accessibility of de novo protein design, faster and cheaper experimental screening methods would democratize and accelerate the identification of high-affinity binders. Here we present Cell-Free Two-Hybrid (CF2H), a rapid and sensitive method for detecting high-affinity protein-protein interactions (PPI) that does not require cloning, protein purification nor high-end laboratory equipment. CF2H uses a dimerization-activated DNA binding domain (DBD) fused to prey and bait proteins to trigger transcription upon protein-protein interaction. We demonstrate that CF2H enables the detection of interactions between various types of target and binder proteins such as single-domain antibodies, DARPins and de novo designed binders. We benchmark CF2H as a screening platform by validating previously reported binders for Mdm2 and discover high-affinity binders targeting the checkpoint inhibitor PD-L1 in less than 24 hours. Finally, we show that CF2H can be used to characterize small-molecules modulators of PPI and detect protein biomarkers, opening the door for a new class of cell-free biosensors.

synthetic biology↗

bioRxiv2024

Neutrophils in People Living With HIV-1 on antiretroviral treatment conserve their cytokine and chemokine secretion capacity and display enhanced expression of Fc receptors

Neutrophils are innate immune cells with key immunomodulatory functions. In a murine retroviral model, we previously showed their essential role in promoting protective immunity during antiviral antibody therapy via Fc-Fc{gamma} receptor (Fc{gamma}R) interactions. Here, we investigated the immunomodulatory properties of neutrophils in the context of HIV-1 infection and therapy through a comprehensive analysis of their functional activation and the regulation of Fc{gamma}R expression. Neutrophils from healthy donors (HD) and people living with HIV-1 (PLWH) were stimulated with TLR ligands, free HIV-1, immune complexes (ICs) formed with broadly neutralizing antibodies (bNAbs), or pro-inflammatory cytokines (TNF, IFN{gamma}). In response, they secreted various cytokines and chemokines that can recruit and activate immune cells in a stimulus-dependent manner. Compared to TLR agonist and cytokine activation, HD neutrophils showed limited cytokine production in response to free HIV-1 or ICs alone as well as a minimal Fc{gamma}R modulation. However, PLWH neutrophils showed heightened responsiveness to microbial stimuli linked to HIV-1 pathogenesis, secreting higher levels of IFN{gamma}, CXCL1, CCL2, CCL3, and CCL4. They also expressed higher levels of two activating Fc{gamma}Rs (Fc{gamma}RI and Fc{gamma}RIIIb), as well as CD11b, CD63, CXCR4, and PD-L1, indicating an altered activation state. These findings highlight the influence of the inflammatory milieu on neutrophil function and Fc{gamma}R regulation in HIV-1 infection and mAb-based therapies.

immunology↗

bioRxiv2021

Loss of BCL-3 sensitises colorectal cancer cells to DNA damage, revealing a role for BCL-3 in double strand break repair by homologous recombination

ObjectiveThe proto-oncogene BCL-3 is upregulated in a subset of colorectal cancers (CRC) and increased expression of the gene correlates with poor patient prognosis. The aim is to investigate whether inhibiting BCL-3 can increase the response to DNA damage in CRC. DesignThe function of BCL-3 in DNA damage response was studied in vitro using siRNA and CRISPR-Cas9 genome editing and in vivo using Bcl3-/- mice. DNA damage induced by {gamma}-irradiation and/or cisplatin was quantified using H2AX and RAD51 foci, repair pathways investigated using HR/NHEJ assays and treatment with the PARP inhibitor olaparib. ResultSuppression of BCL-3 increases double strand break number and decreases homologous recombination in CRC cells, supported by reduced RAD51 foci number and increased sensitivity to PARP inhibition. Importantly, a similar phenotype is seen in Bcl3-/- mice, where the intestinal crypts of these mice exhibit sensitivity to DNA damage and a greater number of double strand breaks compared to wild type mice. Furthermore Apc.Krasmutant x Bcl3-/- mice exhibit increased DNA damage and reduced RAD51+ cells compared to their wild type counterparts when treated with cisplatin. ConclusionThis work identifies BCL-3 as a regulator of the cellular response to DNA damage and suggests that elevated BCL-3 expression could increase resistance of tumour cells to DNA damaging agents including radiotherapy. These findings offer a rationale for targeting BCL-3 in CRC as an adjuvant to conventional therapies and suggest that BCL-3 expression in tumours could be a useful biomarker in stratification of rectal cancer patients for neo-adjuvant chemoradiotherapy.

cancer biology↗

bioRxiv2021

Predicting Individual Task Contrasts From Resting-state Functional Connectivity using a Surface-based Convolutional Network

Task-based and resting-state represent the two most common experimental paradigms of functional neuroimaging. While resting-state offers a flexible and scalable approach for characterizing brain function, task-based techniques provide superior localization. In this paper, we build on recent deep learning methods to create a model that predicts task-based contrast maps from resting-state fMRI scans. Specifically, we propose BrainSurfCNN, a surface-based fully-convolutional neural network model that works with a representation of the brains cortical sheet. Our model achieves state of the art predictive accuracy on independent test data from the Human Connectome Project and yields individual-level predicted maps that are on par with the target-repeat reliability of the measured contrast maps. We also demonstrate that BrainSurfCNN can generalize remarkably well to novel domains with limited training data.

neuroscience↗

bioRxiv2019

Drosophila p38 MAPK Interacts with BAG-3/starvin to Regulate Age-dependent Protein Homeostasis

As organisms age, they often accumulate protein aggregates that are thought to be toxic, potentially leading to age-related diseases. This accumulation of protein aggregates is partially attributed to a failure to maintain protein homeostasis. A variety of genetic factors have been linked to longevity, but how these factors also contribute to protein homeostasis is not completely understood. In order to understand the relationship between aging and protein aggregation, we tested how a gene that regulates lifespan and age-dependent locomotor behaviors, p38 MAPK (p38Kb), influences protein homeostasis as an organism ages. We find that p38Kb regulates age-dependent protein aggregation through an interaction with the Chaperone-Assisted Selective Autophagy complex. Furthermore, we have identified Lamin as an age-dependent target of p38Kb and the Chaperone-Assisted Selective Autophagy complex.

genetics↗