Biology subjects

Noble, A.

Publications and source records attributed to Noble, A..

6 recordsLinked to original sources

bioRxiv2026

Characterisation of prostate cancer sialome re-engineering via CMAH transfection reveals a bystander effect that propagates Neu5Gc presentation to neighbouring cells

Sialic acids are a family of nine-carbon -keto sugars that play essential roles in human health and disease. In mammals, they are found in two main forms: N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), with interactions between Neu5Ac-containing glycans and Siglec receptors on immune cells increasingly recognised as glyco-immune checkpoints, promoting immunosuppression. However, humans do not synthesise Neu5Gc due pseudogenisation of the CMAH gene which encodes the cytidine monophospho-N-acetylneuraminic acid hydroxylase enzyme responsible for CMP-Neu5Ac conversion into CMP-Neu5Gc, which then serves as the donor substrate for sialyltransferases. Here, we investigated the effects of re-engineering tumour cell-surface glycans in a prostate cancer cell model by expressing rat CMAH, thereby enabling the conversion of CMP-Neu5Ac to CMP-Neu5Gc. LNCaP cells transfected with the rat CMAH gene predominantly incorporated Neu5Gc into mucin-associated O-glycans implicated in immune suppression. Treatment with sialidase significantly reduced Neu5Gc expression, indicating that Neu5Gc was presented on cell-surface glycans, while cell-tracing experiments demonstrated the transfer of Neu5Gc to neighbouring cells, revealing a potential bystander effect capable of propagating Neu5Gc expression within the tumour microenvironment.

cancer biology↗

bioRxiv2025

The Actin regulator Mena promotes Wnt signalosome endocytosis and Wnt signalling.

Wnt signaling controls embryonic development and tissue maintenance. Endocytosis of Wnt-receptors is required for signalling, yet uptake mechanisms remain poorly understood. Here, we identify the actin regulator and Ena/VASP protein, Mena, as a key mediator. Upon Wnt stimulation, Mena redistributes from focal adhesions to signalosomes, Wnt-receptor clusters. Mena directly binds Wnt-coreceptors LRP5/6 in a phosphorylation-dependent manner increasing Wnt signal transduction. Sequestration of Ena/VASP proteins impedes in vivo Wnt activation driving Xenopus embryonic development. We resolve previous controversies by showing that Wnt3a triggers rapid Clathrin-Mediated and Fast Endophilin-Mediated LRP6 endocytosis at low concentrations sufficient for Wnt activation. This efficient endocytosis requires Ena/VASP proteins and is specifically promoted by Mena. Our results suggest Mena as a crucial mediator of Wnt signalosome endocytosis thus promoting canonical Wnt signalling.

cell biology↗

bioRxiv2024

Human and Mouse Models for Kabuki Syndrome Reveal Increase in Inhibitory Synapse Development.

Intellectual disability, affecting 2-3% of the general population, often co-occurs with neurodevelopmental disorders and is frequently caused by mutations that impair synaptic function. Kabuki syndrome (KS), a rare multisystem disorder associated with developmental delay and intellectual disability, results from mutations in either KMT2D (KS1) or KDM6A (KS2), encoding a histone methyltransferase and demethylase, respectively. The mechanisms underlying intellectual disability in KS remain poorly understood. Here, we generated human iPS cells carrying conditional Cre/lox-dependent loss-of-function mutations in KMT2D or KDM6A and differentiated them into excitatory or inhibitory neurons. Analysis revealed that KS1 and KS2 inhibitory neurons unexpectedly showed increased GABAergic synapse formation, whereas excitatory neurons displayed reduced synapse development and impaired synaptic transmission. We confirmed these findings in hippocampal neurons in vitro and in vivo using a mouse model for KS1 demonstrating a bidirectional shift: increase in inhibition and decrease in excitation. Synapse numbers and synaptic transmission in brain slices were shifted to increased inhibition/excitation ratio. Mechanistically, KS1 mutations activated neuroinflammatory signaling, impaired astrocytic function, and promoted glia-driven inhibitory synapse formation in human neurons. By integrating human neuron models with conditional KMT2D/KDM6A deletions and a Kmt2d-mutant mouse model, we identify a novel synaptic disease mechanism in KS that links chromatin remodeling defects to disrupted information transfer in neural circuits, providing a mechanistic explanation for intellectual disability. Significance StatementKabuki syndrome, a rare disorder with intellectual disability, is caused by mutations in the chromatin regulators KMT2D and KDM6A, yet its cellular pathophysiology has remained unclear. Using new Cre/lox-inducible human neuron models together with a mouse model, we reveal a conserved excitation-inhibition imbalance characterized by increased inhibitory and decreased excitatory synapse formation. Our findings establish the first mechanistic framework linking KMT2D/KDM6A mutations to synaptic dysfunction, uncover glial contributions to disease pathogenesis, and suggest potential therapeutic avenues for restoring synaptic balance. HighlightsO_LIKS1 and KS2 mutations cause decrease in excitatory synapses in human neurons C_LIO_LIKS1 and KS2 mutations cause increase in inhibitory synapses in human neurons C_LIO_LIKS1 mutation causes decrease in excitatory and increase in inhibitory synapses in mice C_LIO_LIKS1 mutant mouse astrocytes facilitate increase in inhibitory synapses in human neurons C_LI

neuroscience↗

bioRxiv2024

Cleland Immunoblotting Unmasks Unexpected Cysteine Redox Proteoforms

Cysteine redox proteoforms are virtually unstudied because they are extremely difficult to detect. They are difficult to detect by immunoblotting when the polyethylene glycol (PEG)-payloads used to mobility-shift proteoforms into distinct bands block antibody binding. Here, we synthesised a novel compound to reversibly crosslink the PEG-payloads to oxidised cysteines using disulfide bonds. To reductively release the PEG-payloads from mobility-shifted proteoforms, we soaked the gel in Clelands reagent: 1,4-dithiothreitol (DTT). Hence, Cleland immunoblotting. Cleland immunoblotting unmasked hitherto undetectable cysteine redox proteoforms. In Xenopus oocytes, we detected 2 cdc20-specific coordinates in an otherwise abstract space housing 1,024 theoretical proteoforms. The coordinates mapped to the fully, all 10 cysteine residues, 100%-reduced and 100%-oxidised proteoforms. The unexpected absence of partially oxidised molecules along the 10-reaction path to the 100%-oxidised proteoform implies novel biology. By providing the technological means to detect cysteine redox proteoforms, Cleland immunoblotting opens new avenues of discovery.

biochemistry↗

bioRxiv2020

Role for both myeloid and plasmacytoid DC in driving primary T helper cell response to Burkholderia pseudomallei in healthy individuals.

Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis, an infectious disease endemic to south-east Asia. As B. pseudomallei is antibiotic-resistant, the need for cell-based vaccines and therapies is crucial to managing melioidosis. Dendritic cells (DC) provide the first line of defense to infection and direct downstream immune responses. Using practical volumes of fresh healthy donor blood, we show that heat-killed B. pseudomallei activated and stimulated expression of pro-inflammatory cytokines TNF-, IL-1{beta} and IL-6 from both myeloid and plasmacytoid DC. Furthermore, B. pseudomallei-pulsed DC induced activation and proliferation of CD4+ T-cells. Thus, both DC subsets are important for driving primary T helper cell responses to B. pseudomallei in healthy individuals and have the potential to be targeted for future therapies and vaccines. Author SummaryMelioidosis is an infectious disease endemic to south-east Asia and northern Australia caused by the bacterium Burkholderia pseudomallei. Melioidosis presents a significant public health threat because it has no effective vaccine or cure, leading to a high mortality rate of between 10-50%. We highlight the possibility of immune-based strategies targeting Burkholderia pseudomallei to better treat and prevent melioidosis. Specifically, we show that dendritic cells-the sentinel cells of the immune system-respond to B. pseudomallei in healthy individuals and in turn can orchestrate downstream protective immune responses. Thus, dendritic cells may be key players in the development of both vaccines and therapeutics for melioidosis as well as other bacteria-driven diseases.

immunology↗

bioRxiv2017

HTX: a tool for the exploration and visualization of high-throughput image assays

High-throughput screening (HTS) techniques have enabled large scale image-based studies, but extracting biological insights from the imaging data in an exploratory setting remains a challenge. Existing packages for this task either require expert annotations, which can bias the outcome of the study, or are completely unsupervised, failing to leverage the information present in the assay design. We present HTX, an interactive tool to aid in the exploration of large microscopy data sets by allowing the visualization of entire image-based assays according to visual similarities between the samples in an intuitive and navigable manner. Underlying HTX are a collection of novel algorithmic techniques for deep texture descriptor learning, 2D data visualization, adversarial suppression of batch effects, and backprop-based image saliency estimation.\n\nWe demonstrate that HTX can exploit the screen meta-data in order to learn screen-specific image descriptors, which are then used to quantify the visual similarity between samples in the assay. Given these similarities and the different visualization resources of HTX, it is shown that screens of small-molecule libraries on cell data can be easily explored, reproducing the results of previous studies where highly-specific domain knowledge was required.

bioinformatics↗