Biology subjects

Bending, D.

Publications and source records attributed to Bending, D..

12 recordsLinked to original sources

bioRxiv2025

Towards active vaccination against tumour endothelial marker Robo4

Targeting tumour antigens is a major challenge in cancer-immunotherapy. We use active vaccination to induce antibodies targeting self-antigen Robo4, which is selectively expressed on tumour vascular endothelium, supporting vascular development. Our previous work showed that a conjugate of Robo4 with a foreign carrier protein can induce autoantibodies specific to Robo4, which inhibited angiogenesis and tumour growth. The current project aims to translate the vaccine protocol to exploit a carrier protein used in routine human vaccination schedules. The well-characterised, non-toxic fragment C of tetanus toxin (TTc) was selected as the carrier protein. Here we show that priming with the carrier TTc followed by boost with Robo4-TTc (R4-TTc) efficiently induces strong antibody responses to Robo4 and inhibits tumour growth in LLC1 and 4T1 tumour models. The growth inhibition was correlated with anti-Robo4 IgG1 titres. Furthermore, we observed decreased vessel formation and increased immune cell infiltration in tumours from R4-TTc vaccinated mice in the absence of detectable adverse effects on health. The data indicate that this vaccination strategy remodels tumour vessels and probably promotes immunogenic pathway activation, therefore repressing tumour growth. One Sentence SummaryA conjugate vaccine inducing antibody responses to tumour endothelial markers Robo4 can inhibit tumour growth.

immunology↗

bioRxiv2024

Remote force modulation of the T-cell receptor reveals an NFAT-threshold for CD4+ T cell activation

Abstract/SummaryMechano-modulation of cell surface proteins to influence cell activation has been shown as a promising new advanced therapy for regenerative medicine applications. These strategies rely on the manipulation of mechanosensitive cell surface receptors to initiate intracellular signal transduction. The cell surface receptor of T lymphocytes (TCR), which recognises peptide-MHC molecules central to driving the adaptive immune response, has recently been suggested to be mechano-responsive. Despite this advance, little is known as to whether the TCR can be mechanically modulated to achieve TCR signalling and subsequent T cell activation, and whether these characteristics can be exploited for immunotherapies. Here, we describe a magnetic particle-based platform for mechanical modulation of the TCR and outline how this platform can be utilised to achieve CD4+ T cell activation. We demonstrate that mechanical manipulation of the TCR induces cell surface clustering of the TCR and downstream TCR signalling, leading to eventual TCR downregulation and T cell activation. We investigate the temporal relationship between mechanical modulation of the TCR and subsequent T cell activation, hereby identifying that accumulation of signalling events within the NFAT-pathway is required to reach the threshold required for CD4+ T cell activation, outlining an axis which controls the CD4+ T cell response to external mechanical cues. These findings identify how CD4+ T cells can modulate their function in response to such cues, whilst also outlining a remote-magnetic particle-based platform that may be used for the control of T cell responses.

immunology↗

bioRxiv2024

LAG-3 blockade reactivates the CD8+ T cell expansion program to re-expand contracted clones in the tumor

Effective cancer immunotherapy relies on the clonal proliferation and expansion of CD8+ T cells in the tumor1,2. However, our insights into clonal expansions are limited, owing to an inability to track the same clones in tumors over time. Here, we developed a multi-tumor mouse model system to track hundreds of expanding and contracting CD8+ T cell clones over multiple timepoints in tumors of the same individual. Through coupling of clonal expansion dynamics and single-cell RNA/TCR-seq data, we identified a transcriptomic signature in PD-1+Ly108+ precursor exhausted cells3,4 that strongly predicts rates of intratumoral clone expansion in mice and humans. We found that expression of the signature successfully stratifies melanoma patient outcomes to PD-1/PD-L1 blockade5,6. Downregulation of the signature precedes clone contraction - a phase in which clones contract but maintain revivable precursor exhausted cells in the tumor. LAG-3 blockade - an FDA-approved therapy whose effects on CD8+ T cell responses are currently unclear7, re-activates the expansion signature, re-expanding pre-existing clones, including previously contracted clones. These findings reveal how the study of clonal expansion dynamics provide a powerful pan-immunotherapy signature for monitoring immunotherapies, including PD-1/PD-L1 and LAG-3 blockade, with implications for their future development.

immunology↗

bioRxiv2024

Vancomycin impairs macrophage fungal killing by disrupting mitochondrial morphology and function

Vancomycin is a widely prescribed antibiotic used in the treatment of Gram-positive bacterial infections. We recently showed that this antibiotic disrupted protective anti-fungal immune responses via microbiome dysbiosis, enhancing susceptibility to invasive candidiasis. Antibiotics are an independent risk factor for developing this life-threatening fungal infection, but whether microbiota-independent mechanisms also drive this association is not clear. Here, we show that vancomycin directly impairs macrophage responses to Candida albicans, the main causative agent of invasive candidiasis. Vancomycin-treated macrophages were less able to kill C. albicans despite normal phagocytosis rates and were hyper-inflammatory and more likely to die during infection. We found that vancomycin bound to macrophage mitochondria, leading to depolarisation, reduced respiratory capacity and a hyper-fragmented morphology associated with increased ROS production. Taken together, this work demonstrates direct effects of vancomycin on mammalian immune cells, helping us to understand pro-inflammatory effects of this drug and how it promotes susceptibility to life-threatening fungal infection.

immunology↗

bioRxiv2024

Interferonγ and IL-27 positively regulate type 1 regulatory T-cell development during adaptive tolerance

Strong T-cell receptor (TCR) and IL-27 signalling influence type-1 regulatory (Tr1) T-cell development but whether other signals determine their differentiation is unclear. Utilising Tg4 TCR transgenic mice we established a model for rapid Tr1 cell induction. A single high dose of [4Y]-MBP peptide drove the differentiation of Il10+ T-cells with bona fide Tr1 cell protein and mRNA signatures. Kinetic transcriptional analysis revealed that the Tr1 cell module was transient and preceded by a burst of Ifng transcription in CD4+ T-cells. Neutralisation of IFN{gamma} reduced Tr1 cell frequency and strong TCR signalling markers, which was correlated with reduced macrophage activation. Antibody depletion experiments inferred that T-cells - but not NK cells - provided the relevant source of IFN{gamma}. Additionally, we show that blocking IL-27 in combination with IFN{gamma} neutralisation additively reduced Tr1 cell frequency in vivo. These findings reveal that during strong tolerogenic TCR signalling IFN-{gamma} has a non-redundant regulatory role in augmenting the differentiation of Tr1 cells in vivo.

immunology↗

bioRxiv2024

Lag3 and PD-L1 govern T cell receptor signal duration in adaptively tolerised CD4+ T cells

Lag3 and PD-1 are immune checkpoints that regulate T cell responses and are current immunotherapy targets. Yet how they function to control early CD4+ T cell activation remains unclear. Here, we show that the PD-1 and Lag3 pathways exhibit layered control of the early CD4+ T cell activation process, with the effects of Lag3 more pronounced in the presence of PD-1 pathway co-blockade (CB). RNA-sequencing revealed that CB drove an early NFAT-dependent transcriptional profile, including promotion of ICOShi T follicular helper (Tfh) cell differentiation. NFAT pathway inhibition abolished CB-induced upregulation of NFAT-dependent co-receptors ICOS and OX40, whilst unaffecting the NFAT-independent gene Nr4a1. Mechanistically, Lag3 and PD-1 pathways functioned additively to regulate the duration of T cell receptor (TCR) signals during CD4+ T cell re-activation. Our data therefore reveal that PD-1 and Lag3 pathways converge to additively regulate TCR signal duration and NFAT-dependent transcriptional activity during early CD4+ T cell re-activation. HighlightsO_LIPD-1 and Lag3 pathways exhibit layered control of early CD4+ T cell activation C_LIO_LITheir co-blockade enhances NFAT-dependent TCR transcriptional programmes C_LIO_LIInhibition of NFAT signalling reverses the functional effects of PD-1 and Lag3 co-blockade C_LIO_LIMechanistically, PD-1 and Lag3 function to additively regulate TCR signal duration during re-activation of CD4+ T cells C_LI

immunology↗

bioRxiv2023

Rewiring of the TCR signalosome in natural intestinal Intraepithelial T lymphocytes drives non-deletional tolerance

Natural intraepithelial T lymphocytes (T-IELs) are innate-like, intestine-resident T cells essential for gut homeostasis. These cells express self-reactive T cell antigen receptors (TCRs) due to thymic agonist selection, but they do not cause autoimmunity. The mechanism underlying natural T-IELs tolerance in the gut is unclear. Using TCR reporter mouse models and phosphoproteomics, we demonstrate that TCR signaling is intrinsically suppressed in natural T-IELs. We discover that this suppression occurs post-selection in the thymus through altered expression of TCR signalosome components, a mechanism we term RePrESS (Rewiring of Proximal Elements of TCR Signalosome for Suppression). RePrESS is evolutionarily conserved and also found in autoreactive innate-like T cells from skin, breast and prostate. In coeliac disease, tolerance breakdown is associated with loss of RePrESS in natural T-IELs. Our findings reveal a distinct, conserved mechanism of tolerance involving TCR signaling rewiring, with implications for understanding barrier tissue homeostasis and autoimmune disease. One sentence summaryAutoreactive innate-like T lymphocytes are developmentally suppressed by rewiring of the T cell antigen receptor signaling pathway to maintain tolerance.

immunology↗

bioRxiv2023

Salmonella cancer therapy metabolically disrupts tumours at the collateral cost of T cell immunity

Bacterial cancer therapy (BCT) is a promising therapeutic for solid tumours. Salmonella enterica Typhimurium (STm) is well-studied amongst bacterial vectors due to advantages in genetic modification and metabolic adaptation. A longstanding paradox is the redundancy of T cells for treatment efficacy; instead, STm BCT depends on innate phagocytes for tumour control. Here, we used distal T cell receptor (TCR) reporter mice (Nr4a3-Tocky-Ifng-YFP) and a colorectal cancer (CRC) model to interrogate T cell activity during BCT with attenuated STm. We found that colonic TILs exhibited a variety of activation defects, including IFN-{gamma} production decoupled from TCR signalling, decreased polyfunctionality and reduced TCM formation. Modelling of T-cell-tumour interactions with a tumour organoid platform revealed an intact TCR signalosome, but paralysed metabolic reprogramming due to inhibition of the master metabolic controller, c-Myc. Restoration of c-Myc by deletion of the bacterial asparaginase ansB reinvigorated T cell activation, but at the cost of decreased metabolic control of the tumour by STm. This work shows for the first time that T cells are metabolically defective during BCT, but also that this same phenomenon is inexorably tied to intrinsic tumour suppression by the bacterial vector.

immunology↗

bioRxiv2021

Antigen and Checkpoint Receptor Recalibration of T Cell Receptor Signal Strength

How T cell receptor (TCR) signal strength modulates T cell function and to what extent this is modified by immune checkpoint blockade (ICB) are key questions in immunology. Using Nr4a3-Tocky mice as a digital read-out of NFAT pathway activity, we identify the rapid quantitative and qualitative changes that occur in CD4+ T cells in response to a range of TCR signalling strengths. We demonstrate that the time and dose dependent programming of distinct co-inhibitory receptors rapidly re-calibrates T cell activation thresholds. By developing a new in vivo model, we analyse the immediate effects of ICB on T cell re-activation. Our findings reveal that anti-PD1 but not anti-Lag3 immunotherapy leads to an increased TCR signal strength. We define a strong TCR signal metric of five genes specifically upregulated by anti-PD1 in T cells (TCR.strong), which can stratify clinical outcomes during anti-PD1 monotherapy in melanoma patients. Our study therefore reveals how analysis of TCR signal strength - and its manipulation - can provide powerful metrics for monitoring outcomes to immunotherapy. Key PointsO_LITCR signal strength-dependent programming of CD4+ T cells revealed over time in vivo C_LIO_LIInhibitory receptor expression is dynamic, TCR signal strength dependent, and rapidly re-calibrates T cell activation thresholds C_LIO_LIPD1 but not Lag3 blockade leads to a unique and increased TCR signal strength signature (coined TCR.strong) C_LIO_LITCR.strong metric stratifies melanoma patient survival in response to Nivolumab (anti-PD1) therapy C_LI

immunology↗

bioRxiv2019

Distinct regulation of Nr4a receptors by NFAT and ERK signalling during T cell activation

Nr4a receptors are activated by T cell receptor (TCR) and B cell receptor (BCR) signalling and play key roles in T cell differentiation and promoting T cell exhaustion. How TCR signalling pathways regulate Nr4a receptors and their sensitivities to different physiological types of TCR signalling (e.g. tonic versus activating) remains unknown. Here we utilise Nr4a1/Nur77-GFP and Nr4a3-Tocky mice to elucidate the signalling pathways that govern Nr4a receptor expression in CD4+ and CD8+ T cells. Our findings reveal that Nr4a1-3 are Src family kinase-dependent. Moreover, Nr4a2 and Nr4a3 are abolished by calcineurin inhibitors and bind NFAT1, highlighting a necessary and sufficient role for NFAT in the control of Nr4a2 and Nr4a3, but redundancy for NFAT for Nr4a1. During T cell development, Nr4a1 is activated by tonic signalling during TCR-beta selection in the thymus, whilst Nr4a3 requires cognate peptide:MHC interactions for expression. Thus, due to differential sensitivity of Nr4a1 and Nr4a3 to TCR signalling pathways, T cells undergoing tonic versus activating TCR signalling events can be distinguished in vivo.

immunology↗

bioRxiv2018

A temporally dynamic Foxp3 autoregulatory transcriptional circuit controls the effector Treg programme

Regulatory T cells (Treg) are negative regulators of the immune response. Whilst thymic Treg generation is well studied, it is not known whether and how Foxp3 transcription is induced and regulated in the periphery during immune responses. Here we use Foxp3 Timer of cell kinetics and activity (Tocky) mice, which report real-time Foxp3 gene transcription by measuring the spontaneous maturation of Fluorescent Timer protein from Blue to Red fluorescence, to identify the flux of Foxp3-to Foxp3+ T cells within the periphery and analyse the real-time activity of Foxp3 transcription. Using a murine model of skin allergy, we show that both the flux of new Foxp3 expressors and the rate of Foxp3 transcription are increased at inflamed sites. These persistent dynamics of Foxp3 transcription determine the effector Treg programme, and are dependent on a Foxp3 autoregulatory transcriptional circuit, as evidenced by analysis of T cells lacking functional Foxp3 protein. Such reactive and persistent Foxp3 transcriptional activity controls the expression of coinhibitory molecules including CTLA-4 and effector-Treg signature genes. Using RNA-seq, we identify two groups of surface proteins based on their relationship to the temporal dynamics of Foxp3 transcription, and we show proof-of-principle for the manipulation of Foxp3 dynamics by immunotherapy: new Foxp3 flux is promoted by anti-TNFRII antibody, and high frequency Foxp3 expressors are depleted by anti-OX40 antibody. Collectively, our study dissects time-dependent mechanisms behind Foxp3-driven T cell regulation, and establishes the Foxp3-Tocky system as a tool to investigate the mechanisms behind T cell immunotherapies.

immunology↗

bioRxiv2017

An engineered cellular Timer for analysing the time domain of cellular differentiation in vivo

Understanding the mechanisms of cellular differentiation is challenging because differentiation is initiated by signaling pathways that drive temporally dynamic processes, which are difficult to analyse in vivo. We establish a new Tool, Timer-of-cell-kinetics-and-activity (Tocky [toki], time in Japanese). Tocky uses the Fluorescent Timer protein, which spontaneously shifts its emission spectrum from blue-to-red, in combination with computer algorithms to reveal the dynamics of differentiation in vivo. Using a transcriptional target of T cell receptor (TCR)-signaling, we establish Nr4a3-Tocky to follow downstream effects of TCR signaling. Nr4a3-Tocky reveals the temporal sequence of events during regulatory T cell (Treg) differentiation and shows that persistent TCR signals occur during Treg generation. Remarkably, antigen-specific T cells at the site of autoimmune inflammation also show persistent TCR signaling. In addition, by generating Foxp3-Tocky, we reveal the in vivo dynamics of demethylation of the Foxp3 gene. Thus, Tocky is a Tool for cell biologists to address previously inaccessible questions by directly revealing dynamic processes in vivo.\n\nSummaryThe authors establish a new Tool, Timer-of-cell-kinetics-and-activity (Tocky) revealing the temporal dynamics of cellular activation and differentiation in vivo. The tool analyses the temporal sequence of molecular processes during cellular differentiation and identifies cells that receive persistent signals in vivo.

cell biology↗