Biology subjects

Norton, M.

Publications and source records attributed to Norton, M..

7 recordsLinked to original sources

bioRxiv2026

Multiplexed measurements of protein-protein interactions and protein abundance across cellular conditions using Prod&PQ-seq

Methods to profile protein-protein interactions (PPIs) have limited scalability and can only study a handful of conditions and/or targets. Here, we introduce Prod&PQ-seq, a framework for multiplexed detection and quantification of PPIs and proteins. Our framework uses cross-linked cells, antibody-oligonucleotide conjugates (ab-oligos), and captures PPIs by the DNA-caliper, a specialized oligonucleotide for bidirectional priming of proximal ab-oligos. We benchmarked Prod&PQ-seq using recombinant complexes, titrations and cell mixture experiments and show that our framework is quantitative, reproducible, sensitive and specific. Applying Prod&PQ-seq to study Polycomb Repressive Complex 2 (PRC2) shows that EZH2 inhibition and expression of the oncohistone H3.3K27M weakens both PRC2-H3K27me3 interactions and PPIs within PRC2. Further, H3.1K27M and H3.3K27M variants lead to distinct PPI profiles such as the intensity of H3K27ac-K27M or H3K27ac-EED. Together, Prod&PQ-seq enables detection of changes in PPI composition and intensity and protein quantification across biological conditions, small molecule inhibition and genetic perturbations. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=197 HEIGHT=200 SRC="FIGDIR/small/697286v2_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@1ed0805org.highwire.dtl.DTLVardef@a9c0d9org.highwire.dtl.DTLVardef@b411fborg.highwire.dtl.DTLVardef@8a12e_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2025

The microbial tryptophan metabolite indole acts on the gastrointestinal tract to improve glucose homeostasis by enhancing GLP-1 secretion and L-cell differentiation

Aims/hypothesisGrowing evidence implicates gut microbiota-derived metabolites in metabolic homeostasis. Indole, a microbial tryptophan metabolite, has been reported to enhance Glucagon-like peptide-1 (GLP-1) secretion in vitro, and its derivatives have been inversely associated with risk of type 2 diabetes (T2D). We hypothesised that indole acts via the gastrointestinal tract to modulate glucose homeostasis, and aimed to test this hypothesis using in vitro and in vivo models. MethodsThe acute effects of indole on GLP-1 secretion in vitro, and on glucose tolerance and hormone secretion in mice, were determined. Subsequently, the effects of indole on intestinal epithelial cell fate and L-cell differentiation in murine ileal organoids and in vivo were studied. Finally, the utility of chronic indole administration in a murine model of T2D was explored. ResultsIndole stimulated in vitro GLP-1 secretion in a concentration-dependent manner, and improved acute glucose control in vivo. Additionally, we demonstrate that indole drives enteroendocrine L-cell differentiation in murine ileal organoids, resulting in increased L-cell density and longer-term glucoregulatory benefits in vivo. Finally, sub-chronic indole administration improved glucose tolerance and insulin sensitivity in diabetic mice. Conclusions/interpretationOur findings identify indole as an anti-diabetic molecule that acts on the gut, and raise the possibility of incorporating indole into nutraceutical supplements to aid in the treatment or prevention of T2D. This highlights the importance of gut microbiota-derived metabolites in metabolic health and opens new avenues for developing novel strategies to combat T2D. Research in ContextO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LIGut microbiota-derived metabolites play a role in metabolic homeostasis. C_LIO_LIIndole, a microbial tryptophan metabolite, enhances GLP-1 secretion in vitro. C_LIO_LIIndole derivatives are inversely associated with type 2 diabetes (T2D) risk. C_LI What is the key question?O_LIDoes indole act on the gut to modulate glucose homeostasis? C_LI What are the new findings?O_LIIndole stimulates GLP-1 secretion and improves acute glucose control in vivo. C_LIO_LIIndole drives enteroendocrine L-cell differentiation in murine ileal organoids, increasing L-cell density and long-term glucoregulatory benefits. C_LIO_LISub-chronic indole administration improves glucose tolerance and insulin sensitivity in mice with type 2 diabetes, showing the potential of gut microbiota-derived metabolites as therapeutic targets. C_LI How might this impact clinical practice in the foreseeable future?O_LIIndole could be incorporated into nutraceutical supplements for T2D prevention or treatment. C_LI

physiology↗

bioRxiv2025

Extracellular Ca2+-Sensing Receptor (CaSR) Regulates Hypothalamic Function to Control Energy and Skeletal Metabolism in Mice

Introductory paragraphThe extracellular Calcium-sensing receptor (CaSR) regulates cellular responsiveness to physiological changes in ionized calcium (Ca2+) concentrations. The CaSR is expressed in the brain, including in hypothalamic growth hormone stimulating GHRH and anorectic POMC neurons that control growth and energy homeostasis. We embryonically deleted the Casr gene in neurons to create NeuronCaSR-/- mice to delineate the role of this receptor in regulating growth, skeletal development, and energy metabolism. NeuronCaSR-/- mice had reduced size, weight and bone mass compared to littermate controls, with a dysregulated growth hormone axis. They also showed increased adiposity and circulating leptin levels, leptin resistance, and decreased glucose tolerance, along with reduced expression of the anorectic precursor peptide POMC and secondary increases in the expression of the anorectic peptide AgRP in the hypothalamus of NeuronCaSR-/- mice. Knockdown of CaSR in adult mice specifically in the hypothalamic arcuate nucleus, where GHRH, POMC and AgRP neurons reside, also resulted in increased body weight, adiposity, leptin resistance, and glucose intolerance, and reduced bone mass. Together these data suggest that neuronal CaSR critically regulates energy and skeletal metabolism and body growth by modulating hypothalamic function, representing a new paradigm for central integration of calcaemic activities with body function.

physiology↗

bioRxiv2025

NodoMap: a spatio-cellular map of the mouse nodose ganglia

The vagus nerve is a key component of the parasympathetic nervous system, innervating multiple abdominal organs to monitor and regulate their function. It forms the main neural pathway between the gastrointestinal tract and the brain, playing a major role in the regulation of energy homeostasis. The cell bodies for vagal sensory neurons reside in the nodose ganglia, with the left and right ganglia reported to have distinct roles in food intake and reward. Here, we have integrated our own single nucleus RNA sequencing data with multiple publicly available datasets to create a database of 108,482 nuclei and cells, and combined this with spatial transcriptomics to present a spatio-cellular transcriptional map of the mouse nodose ganglia, the NodoMap. Nodose ganglia neuronal cells clustered into twenty-two different subtypes, all found in both left and right nodose ganglia, but with significant differences in gene expression between left and right ganglia across multiple neuronal subtypes. Overnight fasting modulated gene expression across specific neuronal subtypes, including nutrient responsive pathways. Spatial transcriptomics showed that while vagal neuronal types were highly interspersed, patterns of organisation into cellular neighbourhoods could be observed, with neighbourhoods identified of predominantly non-neuronal cells and of different neuronal populations accompanied by glial-like cells. Thus, NodoMap provides a detailed atlas of the mouse nodose ganglia in a spatial context, providing a platform for vagovagal neurocircuit analysis, and serving as an important resource to identify targets for pharmacotherapies for metabolic disease.

physiology↗

bioRxiv2025

Enteropancreatic neurons drive the glucoregulatory response to ingested lipid

Enteropancreatic neurons project from the small intestinal wall to the pancreas. Though well positioned to mediate the effects of ingested nutrients on pancreatic function, the metabolic role of these neurons is unclear. Diets rich in olive oil promote weight loss and improve remission rates in patients with T2DM. Here, we show that olive oil improves acute glucose tolerance by stimulating insulin release via neurotensin receptor type 1 (NTSR1)-expressing enteropancreatic neurons. These neurons are necessary for the effects of olive and neurotensin on glucose tolerance, and their activation is sufficient to improve glucose tolerance. These findings suggest a mechanism by which dietary olive oil regulates blood glucose levels and present a novel functional role for enteropancreatic neurons in regulating glucose homeostasis.

physiology↗

bioRxiv2025

The Freshwater Sounds Archive

Freshwater ecosystems are full of underwater sounds produced by amphibians, aquatic arthropods, reptiles, plants, fishes, and methane bubbles escaping from the sediment. Although much headway has been made in recent years investigating the overall soundscapes of various freshwater ecosystems around the world, there remains a significant knowledge gap in our collective inability to accurately and reliably link recorded sounds with the species that produced them. Here, we present The Freshwater Sounds Archive, a new global initiative, which seeks to address this knowledge gap by collating species-specific freshwater sound recordings into a publicly available database. By means of metadata collection, we also present a snapshot of the species studied, the recording equipment, and recording parameters used by freshwater ecoacousticians globally. In total, 61 entries were submitted to the archive between the 4th of March 2023 and the 30th of April 2025, representing 16 countries and 6 continents. The most numerous taxonomic group was arthropods (29 entries), followed by fishes (14 entries), amphibians (10 entries), macrophytes (7 entries), and a freshwater mollusk (1 entry). The majority of the submissions were from European countries (27 entries), of which the United Kingdom was the most represented with 14 entries. The next most represented region was North America (11 entries), followed by South America (8 entries), Oceania and Asia (5 entries each), Africa (3 entries), and the Middle East and Central America with 1 entry each. The global south, polar regions, and areas with an elevation >500 m (asl) were underrepresented. The field of freshwater ecoacoustics to date has largely focused on the analysis of sound types due to a current lack of knowledge of species-specific sounds. The Freshwater Sounds Archive presents an opportunity to move beyond the sound type approach, and towards an approach with higher taxonomic resolution, ultimately resulting in species-specific descriptions. Furthermore, The Freshwater Sounds Archive will provide freshwater ecoacousticians with one of the main tools required to start creating annotated training datasets for machine learning models from soundscape recordings by referring to known species sounds present in the archive. In the long-term, this will result in the automatic detection and classification of species-specific freshwater sounds from soundscape recordings, such as indicator, invasive, and endangered species.

ecology↗

bioRxiv2022

Intra-islet glucagon signalling regulates pulsatile insulin secretion and glucose homeostasis

BackgroundType 2 diabetes (T2D) is characterised by the loss of pulsatile insulin secretion. We studied mice with {beta}-cell specific loss of the glucagon receptor (Gcgr fl/fl X Ins-1Cre), to investigate the role of intra-islet glucagon receptor signalling on pan-islet calcium oscillations and insulin pulsatility. MethodsFrequently sampled intravenous glucose tolerance tests were conducted on Gcgr {beta}-cell-/- and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for {beta}-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged in vitro and in vivo. Wild-type mice were transplanted with islets expressing GCaMP6f in {beta}-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment. ResultsGcgr {beta}-cell-/- mice exhibited impaired glucose tolerance following intraperitoneal glucose challenge (control 12.7mmol/L {+/-}0.6 vs. Gcgr {beta}-cell-/- 15.4mmol/L {+/-}0.0 at 15 min, p=0.002); fasting glycaemia was not different to controls. In vitro, Gcgr {beta}-cell-/- islets showed profound loss of synchronised calcium waves in response to glucose which was only partially rescued in vivo. First-phase insulin pulsatility on peripheral blood sampling (n=5) was significantly disordered in Gcgr {beta}-cell-/- mice (burst mass Gcgr {beta}-cell-/- 0.30 {+/-}0.03 versus 0.84 {+/-}0.23 for controls p=0.04). Diet induced obesity and hyperglycaemia resulted in a loss of co-ordinated [Ca2+]I waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n=8). ConclusionThese data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised calcium oscillations and support a possible therapeutic role for glucagonergic agents to restore the insulin pulsatility lost in T2D.

physiology↗