Biology subjects

Roberts, W.

Publications and source records attributed to Roberts, W..

4 recordsLinked to original sources

bioRxiv2026

Nitric oxide inhibits platelet adhesion to platelet-microparticles through reducing integrin αIIbβ3 activation

Increased platelet microparticle (PMP) levels in individuals with risk factors for cardiovascular disease correlate with clinical outcomes in these patient groups. PMPs promote thrombosis through enhancing platelet aggregation and binding to the sub-endothelial matrix following vascular injury. Thus, PMPs behave as soluble ligands and adhesive substrates for platelets, and may drive cardiovascular disease progression. Nitric oxide (NO) is released continually from the endothelium as a potent regulator of platelet activation that is crucial to the balance between haemostasis and thrombosis. However, it is unknown if NO regulates PMP-induced platelet activation. In this study we isolated platelets and PMPs from whole blood and measured their interactions in adhesion assays and by flow cytometry. Platelet activation was analysed by ELISA for ADP and thromboxane-B2; both secondary platelet agonists released by activated platelets which enhance thrombosis. The affinity upregulation of the principal platelet integrin receptor responsible for platelet aggregation, integrin IIb{beta}3, was measured using the antibody PAC-1. Our data show that PMP induced platelet adhesion was associated with, and partially dependent upon, platelet ADP release, TxA2 production and IIb{beta}3 upregulation. Crucially, NO dose-dependently reduced these events through cGMP dependent signalling. This is the first report that NO signalling can regulate PMP induced platelet activation and may open an avenue of exploration for clinically targeting PMP driven cardiovascular disease processes.

cell biology↗

bioRxiv2026

Stress-responsive enhancer RNAs couple chromatin reprogramming to post-transcriptional control of senescence

BackgroundCellular senescence is accompanied by extensive epigenomic reprogramming leading to changes in enhancer RNA levels, yet how enhancer activity is translated into functional RNA-level regulation remains unclear. Here we investigate how enhancer reprogramming during senescence impacts functional RNA-level regulation by eRNAs. ResultsBy integrating time-resolved transcriptomic analyses across multiple primary human cell types, we identify a set of recurrently dysregulated senescence-associated enhancer RNAs (SAeRs). We focus on one of these transcripts, EN526, which is reproducibly repressed during senescence while its locus remains broadly stable across cell states. EN526 eRNA exhibits cytoplasmic localisation and extensive eRNA-mRNA interactions, and cytoplasmic depletion of EN526 recapitulates its senescence-associated loss and alters the stability and translation of the cell-cycle regulator CDKN2C. EN526 perturbation further mediates stress responses, cellular survival, and extracellular remodelling associated with the senescence phenotype. ConclusionTogether, these findings show that SAeRs changes accompanying enhancer reprogramming in senescence are not merely passive events but can act as functional intermediates linking enhancer dynamics to post-transcriptional regulatory networks that phenocopy key senescence-associated cellular features. Extending this model, genetic associations at the EN526 locus further connect this regulatory axis to age-related traits and circulating protein phenotypes, supporting its broader relevance to human ageing and disease.

genomics↗

bioRxiv2025

Extracellular vesicles from a model of melanoma cancer-associated fibroblasts induce changes in brain microvascular cells consistent with pre-metastatic niche priming.

Malignant melanoma has one of the lowest 5-year survival rates of any cancer, and is recognised for being particularly invasive and metastatic, with the poorest survival outcomes in brain metastases patients. A key characteristic of these tumours is crosstalk between melanoma cells and cells of the tumour microenvironment (TME), such as cancer associated fibroblasts (CAFs). The role of melanoma-derived small extracellular vesicles (sEVs) in potentiating CAFs has been studied extensively, however the role of CAF sEVs in regulation of the local TME and distal pre-metastatic niche (PMN) is less clear. Here, we demonstrate that sEVs derived from an in vitro model of melanoma CAFs alter melanoma to promote oncogenic parameters within models of the TME and target a model of the brain PMN to promote changes associated with melanoma extravasation. Cargo profiling of these sEVs found significant differential expression of proteins, and RNA associated with pre-metastatic niche remodelling and unfavourable outcomes in patients. Together these data suggest a role for CAF sEVs in local and distal PMN formation, highlighting a potential therapeutic target for metastatic melanoma and identifying prospective liquid biomarker reservoirs.

cancer biology↗

bioRxiv2017

Mapping nonapoptotic caspase activity with a transgenic reporter in mice

The protease caspase-3 is a key mediator of apoptotic programmed cell death. But weak or transient caspase activity can contribute to neuronal differentiation, axonal pathfinding, and synaptic long-term depression. Despite the importance of sublethal, or nonapoptotic, caspase activity in neurodevelopment and neural plasticity, there has been no simple method for mapping and quantifying nonapoptotic caspase activity in rodent brains. We therefore generated a transgenic mouse expressing a highly sensitive and specific fluorescent reporter of caspase activity, with peak signal localized to the nucleus. As a proof of concept, we first obtained evidence that nonapoptotic caspase activity influences neurophysiology in an amygdalar circuit. Then focusing on the amygdala, we were able to quantify a sex-specific persistent elevation in caspase activity in females after restraint stress. This simple in vivo caspase activity reporter will facilitate systems-level studies of apoptotic and nonapoptotic phenomena in behavioral and pathological models. Significance StatementCaspase-3 is an enzyme that can cause cell death when highly active but can also perform important cellular functions, such as maturation and structural changes, when only weakly or transiently active. Despite the importance of this nonlethal type of caspase activity, there is no straightforward method to measure it in live rodents. We therefore developed mice that have a fluorescent reporter that is sensitive enough to detect nonlethal caspase activity. Surprisingly, we found that weak caspase activity influences the synchrony of neuronal firing across different brain regions. We also observed increased caspase activity in female mice after severe stress. This simple caspase activity reporter can subserve multiple applications in behavior and pathology research.

neuroscience↗