Publications
136 results found
Xu W, Qadir MMF, Nasteska D, et al., 2023, Architecture of androgen receptor pathways amplifying glucagon-like peptide-1 insulinotropic action in male pancreatic β cells., Cell Rep, Vol: 42
Male mice lacking the androgen receptor (AR) in pancreatic β cells exhibit blunted glucose-stimulated insulin secretion (GSIS), leading to hyperglycemia. Testosterone activates an extranuclear AR in β cells to amplify glucagon-like peptide-1 (GLP-1) insulinotropic action. Here, we examined the architecture of AR targets that regulate GLP-1 insulinotropic action in male β cells. Testosterone cooperates with GLP-1 to enhance cAMP production at the plasma membrane and endosomes via: (1) increased mitochondrial production of CO2, activating the HCO3--sensitive soluble adenylate cyclase; and (2) increased Gαs recruitment to GLP-1 receptor and AR complexes, activating transmembrane adenylate cyclase. Additionally, testosterone enhances GSIS in human islets via a focal adhesion kinase/SRC/phosphatidylinositol 3-kinase/mammalian target of rapamycin complex 2 actin remodeling cascade. We describe the testosterone-stimulated AR interactome, transcriptome, proteome, and metabolome that contribute to these effects. This study identifies AR genomic and non-genomic actions that enhance GLP-1-stimulated insulin exocytosis in male β cells.
Mendive-Tapia L, Miret-Casals L, Barth ND, et al., 2023, Acid-Resistant BODIPY Amino Acids for Peptide-Based Fluorescence Imaging of GPR54 Receptors in Pancreatic Islets., Angew Chem Int Ed Engl, Vol: 62
The G protein-coupled kisspeptin receptor (GPR54 or KISS1R) is an important mediator in reproduction, metabolism and cancer biology; however, there are limited fluorescent probes or antibodies for direct imaging of these receptors in cells and intact tissues, which can help to interrogate their multiple biological roles. Herein, we describe the rational design and characterization of a new acid-resistant BODIPY-based amino acid (Trp-BODIPY PLUS), and its implementation for solid-phase synthesis of fluorescent bioactive peptides. Trp-BODIPY PLUS retains the binding capabilities of both short linear and cyclic peptides and displays notable turn-on fluorescence emission upon target binding for wash-free imaging. Finally, we employed Trp-BODIPY PLUS to prepare some of the first fluorogenic kisspeptin-based probes and visualized the expression and localization of GPR54 receptors in human cells and in whole mouse pancreatic islets by fluorescence imaging.
Pezhman L, Hopkin SJ, Begum J, et al., 2023, PEPITEM modulates leukocyte trafficking to reduce obesity-induced inflammation., Clin Exp Immunol, Vol: 212, Pages: 1-10
Dysregulation of leukocyte trafficking, lipid metabolism, and other metabolic processes are the hallmarks that underpin and drive pathology in obesity. Current clinical management targets alternations in lifestyle choices (e.g. exercise, weight loss) to limit the impact of the disease. Crucially, re-gaining control over the pathogenic cellular and molecular processes may offer an alternative, complementary strategy for obese patients. Here we investigate the impact of the immunopeptide, PEPITEM, on pancreas homeostasis and leukocyte trafficking in mice on high-fed obesogenic diet (HFD). Both prophylactic and therapeutic treatment with PEPITEM alleviated the effects of HFD on the pancreas, reducing pancreatic beta cell size. Moreover, PEPITEM treatment also limited T-cell trafficking (CD4+ T-cells and KLRG1+ CD3+ T-cells) to obese visceral, but not subcutaneous, adipose tissue. Similarly, PEPITEM treatment reduced macrophage numbers within the peritoneal cavity of mice on HFD diet at both 6 and 12 weeks. By contrast, PEPITEM therapy elevated numbers of T and B cells were observed in the secondary lymphoid tissues (e.g. spleen and inguinal lymph node) when compared to the untreated HFD controls. Collectively our data highlights the potential for PEPITEM as a novel therapy to combat the systemic low-grade inflammation experienced in obesity and minimize the impact of obesity on pancreatic homeostasis. Thus, offering an alternative strategy to reduce the risk of developing obesity-related co-morbidities, such as type 2 diabetes mellitus, in individuals at high risk and struggling to control their weight through lifestyle modifications.
Romano N, Lafont C, Campos P, et al., 2023, Median eminence blood flow influences food intake by regulating ghrelin access to the metabolic brain, JCI INSIGHT, Vol: 8
Viloria K, Nasteska D, Ast J, et al., 2023, GC-Globulin/Vitamin D-Binding Protein Is Required for Pancreatic α-Cell Adaptation to Metabolic Stress., Diabetes, Vol: 72, Pages: 275-289
GC-globulin (GC), or vitamin D-binding protein, is a multifunctional protein involved in the transport of circulating vitamin 25(OH)D and fatty acids, as well as actin scavenging. In the pancreatic islets, the gene encoding GC, GC/Gc, is highly localized to glucagon-secreting α-cells. Despite this, the role of GC in α-cell function is poorly understood. We previously showed that GC is essential for α-cell morphology, electrical activity, and glucagon secretion. We now show that loss of GC exacerbates α-cell failure during metabolic stress. High-fat diet-fed GC-/- mice have basal hyperglucagonemia, which is associated with decreased α-cell size, impaired glucagon secretion and Ca2+ fluxes, and changes in glucose-dependent F-actin remodelling. Impairments in glucagon secretion can be rescued using exogenous GC to replenish α-cell GC levels, increase glucagon granule area, and restore the F-actin cytoskeleton. Lastly, GC levels decrease in α-cells of donors with type 2 diabetes, which is associated with changes in α-cell mass, morphology, and glucagon expression. Together, these data demonstrate an important role for GC in α-cell adaptation to metabolic stress.
Ast J, Nasteska D, Fine NHF, et al., 2023, Revealing the tissue-level complexity of endogenous glucagon-like peptide-1 receptor expression and signaling., Nat Commun, Vol: 14
The glucagon-like peptide-1 receptor (GLP1R) is a class B G protein-coupled receptor (GPCR) involved in glucose homeostasis and food intake. GLP1R agonists (GLP1RA) are widely used in the treatment of diabetes and obesity, yet visualizing the endogenous localization, organization and dynamics of a GPCR has so far remained out of reach. In the present study, we generate mice harboring an enzyme self-label genome-edited into the endogenous Glp1r locus. We also rationally design and test various fluorescent dyes, spanning cyan to far-red wavelengths, for labeling performance in tissue. By combining these technologies, we show that endogenous GLP1R can be specifically and sensitively detected in primary tissue using multiple colors. Longitudinal analysis of GLP1R dynamics reveals heterogeneous recruitment of neighboring cell subpopulations into signaling and trafficking, with differences observed between GLP1RA classes and dual agonists. At the nanoscopic level, GLP1Rs are found to possess higher organization, undergoing GLP1RA-dependent membrane diffusion. Together, these results show the utility of enzyme self-labels for visualization and interrogation of endogenous proteins, and provide insight into the biology of a class B GPCR in primary cells and tissue.
Trumpp M, Oliveras A, Gonschior H, et al., 2022, Enzyme self-label-bound ATTO700 in single-molecule and super-resolution microscopy, CHEMICAL COMMUNICATIONS, Vol: 58, Pages: 13724-13727, ISSN: 1359-7345
Kravets V, Dwulet JM, Schleicher WE, et al., 2022, Functional architecture of pancreatic islets identifies a population of first responder cells that drive the first-phase calcium response, PLOS BIOLOGY, Vol: 20, ISSN: 1544-9173
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- Citations: 3
Cahil KN, Amin T, Boutaud O, et al., 2022, Glucagon-Like Peptide-1 Receptor Regulates Thromboxane-Induced Activation, JACC-BASIC TO TRANSLATIONAL SCIENCE, Vol: 7, Pages: 713-715, ISSN: 2452-302X
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- Citations: 3
Michau A, Lafont C, Bargi-Souza P, et al., 2022, Metabolic Stress Impairs Pericyte Response to Optogenetic Stimulation in Pancreatic Islets, FRONTIERS IN ENDOCRINOLOGY, Vol: 13, ISSN: 1664-2392
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- Citations: 1
Mugabo Y, Zhao C, Tan JJ, et al., 2022, 14-3-3 sigma Constrains insulin secretion by regulating mitochondrial function in pancreatic beta cells, JCI INSIGHT, Vol: 7
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- Citations: 2
Guerineau NC, Campos P, Le Tissier PR, et al., 2022, Cell Networks in Endocrine/Neuroendocrine Gland Function, COMPREHENSIVE PHYSIOLOGY, Vol: 12, Pages: 3371-3415, ISSN: 2040-4603
Karsai M, Zuellig RA, Lehmann R, et al., 2022, Lack of ZnT8 protects pancreatic islets from hypoxia- and cytokine-induced cell death, JOURNAL OF ENDOCRINOLOGY, Vol: 253, Pages: 1-11, ISSN: 0022-0795
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- Citations: 3
Allen SL, Seabright AP, Quinlan J, et al., 2022, The Effect of Ex Vivo Human Serum from Liver Disease Patients on Cellular Protein Synthesis and Growth, CELLS, Vol: 11
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- Citations: 1
Pauza AG, Thakkar P, Tasic T, et al., 2022, GLP1R Attenuates Sympathetic Response to High Glucose via Carotid Body Inhibition, CIRCULATION RESEARCH, Vol: 130, Pages: 694-707, ISSN: 0009-7330
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- Citations: 12
Birke R, Ast J, Roosen DA, et al., 2022, Sulfonated red and far-red rhodamines to visualize SNAP- and Halo-tagged cell surface proteins, ORGANIC & BIOMOLECULAR CHEMISTRY, Vol: 20, Pages: 5967-5980, ISSN: 1477-0520
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- Citations: 4
Westbrook RL, Bridges E, Roberts J, et al., 2022, Proline synthesis through PYCR1 is required to support cancer cell proliferation and survival in oxygen-limiting conditions, CELL REPORTS, Vol: 38, ISSN: 2211-1247
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- Citations: 5
Hoang M, Jentz E, Janssen SM, et al., 2022, Isoform-specific Roles of Prolyl Hydroxylases in the Regulation of Pancreatic beta-Cell Function, ENDOCRINOLOGY, Vol: 163, ISSN: 0013-7227
Costa A, Ai M, Nunn N, et al., 2021, Anorectic and aversive effects of GLP-1 receptor agonism are mediated by brainstem cholecystokinin neurons, and modulated by GIP receptor activation, MOLECULAR METABOLISM, Vol: 55, ISSN: 2212-8778
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- Citations: 6
Ast J, Broichhagen J, Hodson DJ, 2021, Reagents and models for detecting endogenous GLP1R and GIPR, EBIOMEDICINE, Vol: 74, ISSN: 2352-3964
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- Citations: 6
Cartwright DM, Oakey LA, Fletcher RS, et al., 2021, Nicotinamide riboside has minimal impact on energy metabolism in mouse models of mild obesity., J Endocrinol, Vol: 251, Pages: 111-123
Supplementation with precursors of NAD has been shown to prevent and reverse insulin resistance, mitochondrial dysfunction, and liver damage in mouse models of diet-induced obesity. We asked whether the beneficial effects of supplementation with the NAD precursor nicotinamide riboside (NR) are dependent on mouse strain. We compared the effects of NR supplementation on whole-body energy metabolism and mitochondrial function in mildly obese C57BL/6N and C57BL/6J mice, two commonly used strains to investigate metabolism. Male C57BL/6N and C57BL/6J mice were fed a high-fat diet (HFD) or standard chow with or without NR supplementation for 8 weeks. Body and organ weights, glucose tolerance, and metabolic parameters as well as mitochondrial O2 flux in liver and muscle fibers were assessed. We found that NR supplementation had no influence on body or organ weight, glucose metabolism or hepatic lipid accumulation, energy expenditure, or metabolic flexibility but increased mitochondrial respiration in soleus muscle in both mouse strains. Strain-dependent differences were detected for body and fat depot weight, fasting blood glucose, hepatic lipid accumulation, and energy expenditure. We conclude that, in mild obesity, NR supplementation does not alter metabolic phenotype in two commonly used laboratory mouse strains.
Pickford P, Lucey M, Rujan R-M, et al., 2021, Partial agonism improves the anti-hyperglycaemic efficacy of an oxyntomodulin-derived GLP-1R/GCGR co-agonist, Molecular Metabolism, Vol: 51, ISSN: 2212-8778
OBJECTIVE: Glucagon-like peptide-1 and glucagon receptor (GLP-1R/GCGR) co-agonism can maximise weight loss and improve glycaemic control in type 2 diabetes and obesity. In this study we investigated the cellular and metabolic effects of modulating the balance between G protein and β-arrestin-2 recruitment at GLP-1R and GCGR using oxyntomodulin (OXM)-derived co-agonists. This strategy has been previously shown to improve the duration of action of GLP-1R mono-agonists by reducing target desensitisation and downregulation. METHODS: Dipeptidyl dipeptidase-4 (DPP-4)-resistant OXM analogues were generated and assessed for a variety of cellular readouts. Molecular dynamic simulations were used to gain insights into the molecular interactions involved. In vivo studies were performed in mice to identify effects on glucose homeostasis and weight loss. RESULTS: Ligand-specific reductions in β-arrestin-2 recruitment were associated with slower GLP-1R internalisation and prolonged glucose-lowering action in vivo. The putative benefits of GCGR agonism were retained, with equivalent weight loss compared to the GLP-1R mono-agonist liraglutide in spite of a lesser degree of food intake suppression. The compounds tested showed only a minor degree of biased agonism between G protein and β-arrestin-2 recruitment at both receptors and were best classified as partial agonists for the two pathways measured. CONCLUSIONS: Diminishing β-arrestin-2 recruitment may be an effective way to increase the therapeutic efficacy of GLP-1R/GCGR co-agonists. These benefits can be achieved by partial rather than biased agonism.
Nasteska D, Cuozzo F, Viloria K, et al., 2021, Prolyl-4-hydroxylase 3 maintains beta cell glucose metabolism during fatty acid excess in mice, JCI INSIGHT, Vol: 6
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- Citations: 2
Ast J, Novak AN, Podewin T, et al., 2021, An expanded LUXendin color palette for GLP1R detection and visualization in vitro and in vivo, Publisher: ChemRxiv
The glucagon-like peptide-1 receptor (GLP1R) is expressed in peripheral tissues and the brain, where it exerts pleiotropic actions on metabolic and inflammatory processes. Detection and visualization of GLP1R remains challenging, partly due to a lack of validated reagents. Previously, we generated LUXendins, antagonistic red and far-red fluorescent probes for specific labeling of GLP1R in live and fixed cells/tissue. We now extend this concept to the green and near-infrared color ranges by synthesizing and testing LUXendin492, LUXendin551, LUXendin615 and LUXendin762. All four probes brightly and specifically label GLP1R in cells and pancreatic islets. Further, LUXendin551 acts as chemical beta cell reporter in preclinical rodent models, while LUXendin762 allows non-invasive imaging, highlighting differentially-accessible GLP1R populations. We thus expand the color palette of LUXendins to seven different spectra, opening up a range of experiments using widefield microscopy available in most labs through super-resolution imaging and whole animal imaging. With this, we expect that LUXendins will continue to generate novel and specific insight into GLP1R biology.
Nasteska D, Fine NHF, Ashford FB, et al., 2021, PDX1(LOW) MAFA(LOW) beta-cells contribute to islet function and insulin release (vol 12, 674, 2021), NATURE COMMUNICATIONS, Vol: 12, ISSN: 2041-1723
Viloria K, Hewison M, Hodson DJ, 2021, Vitamin D binding protein/GC-globulin: a novel regulator of alpha cell function and glucagon secretion, JOURNAL OF PHYSIOLOGY-LONDON, Vol: 600, Pages: 1119-1133, ISSN: 0022-3751
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- Citations: 1
McLean BA, Wong CK, Campbell JE, et al., 2021, Revisiting the Complexity of GLP-1 Action from Sites of Synthesis to Receptor Activation, ENDOCRINE REVIEWS, Vol: 42, Pages: 101-132, ISSN: 0163-769X
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- Citations: 55
Nasteska D, Fine NHF, Ashford FB, et al., 2021, PDX1(LOW) MAFA(LOW) beta-cells contribute to islet function and insulin release, NATURE COMMUNICATIONS, Vol: 12
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- Citations: 26
Jones B, Fang Z, Chen S, et al., 2020, Ligand-specific factors influencing GLP-1 receptor post-endocytic trafficking and degradation in pancreatic beta cells, International Journal of Molecular Sciences, Vol: 212, Pages: 1-24, ISSN: 1422-0067
The glucagon-like peptide-1 receptor (GLP-1R) is an important regulator of blood glucose homeostasis. Ligand-specific differences in membrane trafficking of the GLP-1R influence its signalling properties and therapeutic potential in type 2 diabetes. Here, we have evaluated how different factors combine to control the post-endocytic trafficking of GLP-1R to recycling versus degradative pathways. Experiments were performed in primary islet cells, INS-1 832/3 clonal beta cells and HEK293 cells, using biorthogonal labelling of GLP-1R to determine its localisation and degradation after treatment with GLP-1, exendin-4 and several further GLP-1R agonist peptides. We also characterised the effect of a rare GLP1R coding variant, T149M, and the role of endosomal peptidase endothelin-converting enzyme-1 (ECE-1), in GLP1R trafficking. Our data reveal how treatment with GLP-1 versus exendin-4 is associated with preferential GLP-1R targeting towards a recycling pathway. GLP-1, but not exendin-4, is a substrate for ECE-1, and the resultant propensity to intra-endosomal degradation, in conjunction with differences in binding affinity, contributes to alterations in GLP-1R trafficking behaviours and degradation. The T149M GLP-1R variant shows reduced signalling and internalisation responses, which is likely to be due to disruption of the cytoplasmic region that couples to intracellular effectors. These observations provide insights into how ligand- and genotype-specific factors can influence GLP-1R trafficking.
Ast J, Arvaniti A, Fine NHF, et al., 2020, Author Correction: Super-resolution microscopy compatible fluorescent probes reveal endogenous glucagon-like peptide-1 receptor distribution and dynamics., Nature Communications, Vol: 11, Pages: 1-1, ISSN: 2041-1723
Correction to: Nature Communications https://doi.org/10.1038/s41467-020-14309-w, published online 24 January 2020.
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