Linking GPCR organization states with functional heterogeneity in the pancreatic islet

Lead Research Organisation: University of Oxford
Department Name: RDM OCDEM

Abstract

The current view of tissue complexity is mainly based upon single-cell screening technologies, which classify cells according to shared traits, such as maturity, proliferative capacity and mutational potential. Often, inferences about cell function are based upon measurements made outside of the tissue context, as well as the characteristics of the state to which the cell belongs. Thus, immature cells tend to be considered as proliferative, but poorly functional, whereas more mature cells are long-lived and highly functional. While single-cell screening approaches are high-dimensional, they do not have the spatiotemporal resolution inherent to light microscopy. The present proposal will leverage recent advances in genome editing, protein labelling, super-resolution imaging and spatial transcriptomics to provide a higher-order in situ organization of cell heterogeneity at the tissue level, with repercussions for our understanding of tissue (dys)function. Using pancreatic islets as an exemplar micro-organ, and GPCRs as candidate cell surface signalling proteins, we will: 1) map GPCR organization/dynamics at the cell population level and integrate this information with underlying transcriptomic features, before re-classifying cell states; 2) understand how higher-order GPCR organization/dynamics change during cell stimulation, metabolic stress and other states of tissue perturbation; 3) functionally interrogate cell states defined by GPCR organization/dynamics using novel activity integrators and cell-specific transcription factor re-expression; and 4) examine higher-order cell heterogeneity across species. The proposed work will show for the first time how the organization and dynamics of individual signalling proteins relate to cell state and cell activity across the cell population. More broadly, these studies will establish a high-resolution view of cell heterogeneity, leading to a step-change in our understanding of the functional organisation of complex tissues.

Publications

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Mendive-Tapia L (2023) Acid-Resistant BODIPY Amino Acids for Peptide-Based Fluorescence Imaging of GPR54 Receptors in Pancreatic Islets. in Angewandte Chemie (International ed. in English)

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Peercy B (2024) Synchronizing beta cells in the pancreas in eLife

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Pezhman L (2023) PEPITEM modulates leukocyte trafficking to reduce obesity-induced inflammation in Clinical and Experimental Immunology

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Rückert AK (2023) Fine-tuned photochromic sulfonylureas for optical control of beta cell Ca2+ fluxes. in Diabetic medicine : a journal of the British Diabetic Association

 
Description Steve Morgan Foundation-Diabetes UK Grand Challenge
Amount £2,546,826 (GBP)
Funding ID 23/0006627 
Organisation Diabetes UK 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2024 
End 03/2029
 
Title Chemical probes for the detection and visualization of GIPR 
Description We developed the GIPR probes and are testing their specificity in pancreatic islets. Our partners (Frank Reimann and Fiona Gribble) are testing the ligands in the brain. We recently filed a European patent to protect intellectual property surrounding these probes, and will look to commercialize going forward. 
Type Of Material Technology assay or reagent 
Year Produced 2023 
Provided To Others? Yes  
Impact There is no specific antibody for GIPR, which is holding back understanding of sites of action of this important therapeutic receptor. 
 
Title Chemical probes for the detection and visualization of tirzepatide targets (2024) 
Description Fluorescently labelled tirzepatide to delineate target GLP1R/GIPR binding sites in the periphery and brain, which might underlie effects of the drug on glucose homeostasis and food intake. 
Type Of Material Technology assay or reagent 
Year Produced 2023 
Provided To Others? No  
Impact Tirzepatide is a major new drug therapy for type 2 diabetes and obesity. The cells/neurons that tirzepatide binds to exert its biological effects are unknown, in part due to unreliable antibodies for GLP1R/GIPR. Fluorescently-labelled tirzepatide is thus very timely for the field, allowing us to understand how this drug distributes in the body. 
 
Description Development and testing of GIPR probes 
Organisation University of Cambridge
Department Institute of Metabolic Science (IMS)
Country United Kingdom 
Sector Academic/University 
PI Contribution We have developed GIPR probes. No antibody exists for this GPCR, which is becoming translationally very relevant, since it is targeted by GLP1R/GIPR dual agonists for the treatment of diabetes and obesity.
Collaborator Contribution We developed the GIPR probes and are testing their specificity in pancreatic islets. Our partners (Frank Reimann and Fiona Gribble) are testing the ligands in the brain. We recently filed a European patent to protect intellectual property surrounding these probes, and will look to commercialize going forward.
Impact The partnership is still in its early phase, but we have already filed a patent, have a mansucript under revision with Eli Lilly and University Cambridge. The collaboration is multi-disciplinary spanning chemical biology, neuroscience, and involves an industrial partner (Eli Lilly).
Start Year 2021
 
Description Endogenous GPCR clustering analysis 
Organisation University of Birmingham
Country United Kingdom 
Sector Academic/University 
PI Contribution We collaborated with Prof Dylan Owen's lab to perform dSTORM microscopy, as well as clustering analysis of the ensuing datasets.
Collaborator Contribution Dylan's lab provided free time on an ONI nanoimager system (usually 37 GBP per hr), as well as technical assistance with analysis.
Impact We recently published a manuscript together in Nature Communications, which shows data from the collaboration. https://pubmed.ncbi.nlm.nih.gov/36653347/
Start Year 2021
 
Description Optimization of methods to purify stem cell-derived beta cells 
Organisation Novo Nordisk
Department Novo Nordisk Research Centre Oxford
Country United Kingdom 
Sector Private 
PI Contribution We discovered that only ~ 50% of stem cell-derived beta cells (SBC) express GLP1R, a mature functional marker. Using our proprietary technology (GLP1R chemical probes), we have devised steps to increase mature SBC yield by sorting according to GLP1R positivity.
Collaborator Contribution Novo Nordisk Research Centre Oxford funded a postdoctoral researcher to conduct the research. They also provide access to their facility, including provision of reagent for production and screening of SBCs.
Impact N/A
Start Year 2023
 
Description Diabetes UK supporter visit 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Patients, carers and/or patient groups
Results and Impact Diabetes UK site visit for their South East supporter group, including individuals with lived experience. Visitors were provided with an overview of MRC-funded activities, as well as provided with a tour of OCDEM clinical research unit, islet transplantation and research facilities, including hands-on demos.
Year(s) Of Engagement Activity 2023
 
Description Oxford Science and Ideas Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The lab participated in the Oxford Science Festival, on behalf of the Radcliffe Department of Medicine. We set up a stall with hands-on demo relevant to diabetes/obesity.
Year(s) Of Engagement Activity 2023
URL https://if-oxford.com/events/