Biology subjects

Beck-Sickinger, A. G.

Publications and source records attributed to Beck-Sickinger, A. G..

4 recordsLinked to original sources

bioRxiv2026

Neuropeptide Y4 receptor activation delays autoimmune diabetes by reprogramming β-cell stress and immune tolerance

Type 1 diabetes (T1D) involves immune-mediated destruction of pancreatic {beta}-cells, yet current disease-modifying therapies mainly target immunity without enhancing {beta}-cell resilience. We show selective neuropeptide Y4 receptor (Y4R) agonism protects {beta}-cells while reshaping islet immunity across T1D models. Multi-modal localisation using cell sorting, qPCR, RNAscope and fluorescent ligand competition demonstrated predominant Y4R expression and functional accessibility on mouse and human {beta}-cells. Selective Y4R agonism was non-toxic and did not impair islet network integrity, Ca{superscript 2} dynamics, glucose-stimulated insulin secretion or systemic glucose tolerance. Y4R activation conferred cytoprotection against inflammatory cytokines, streptozotocin, lipotoxicity and ER stress, reducing caspase-3/7 activation and {beta}-cell loss whilst sustaining insulin release and promoting proliferation in both mouse and human islets. Bulk RNA-seq revealed a coordinated {beta}-cell resilience programme characterised by reinforced identity and insulin processing, KEAP1-NFE2L2-driven antioxidative and proteostatic activation, and suppression of EIF2 signalling and associated biosynthetic and ER stress pathways. Concurrently, Y4R agonism dampened pathogenic chemokine and cytokine networks, including CXCL10, CCL3/4/7 and IL-6, while preserving IL-2 and Foxp3 signals, thereby limiting CD8 T cell, CD4 T cell and macrophage chemotaxis toward cytokine-stressed islets. Reduced immune-cell recruitment was conserved in a fully human immune-islet system, where Y4R activation significantly attenuated IL-2-activated human PBMC migration and invasion toward cytokine-stressed human islets. In a stringent NY8.3 CD8 T cell adoptive-transfer model, systemic Y4R agonism significantly delayed diabetes onset. These data position Y4R as a {beta}-cell-centric therapeutic target coupling intrinsic resilience with local immune modulation, offering a complementary approach for {beta}-cell preservation in T1D and islet replacement therapies. Graphical abstractThe selective Y4 receptor agonist K22 binds {beta}-cell-enriched NPY4R in mouse and human islets, activates a {beta}-cell resilience programme that preserves insulin secretion under inflammatory and metabolic stress, and simultaneously dampens islet chemokine output, thereby limiting innate and adaptive immune-cell recruitment and delaying autoimmune diabetes onset. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=119 SRC="FIGDIR/small/736290v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@7efd48org.highwire.dtl.DTLVardef@1268860org.highwire.dtl.DTLVardef@c38a81org.highwire.dtl.DTLVardef@1ba3e6c_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

Identification of key Y4R residues enables the discovery of selective non-peptide small-molecule agonists

G protein-coupled receptors (GPCRs) are central regulators of human physiology and disease, classifying them as relevant targets for therapeutic interventions. As transmembrane proteins, they convert extracellular signals into intracellular responses through agonist-induced conformational changes. Understanding how agonists stabilize active receptor conformations is decisive for rational drug design. In this study, we used the endogenous ligand pancreatic polypeptide (PP) and the cyclic hexapeptides UR-AK95c and UR-AK86c as molecular tools to determine key interactions critical for Y4R activation, which plays a crucial role in metabolic diseases. Guided by molecular docking, we systematically replaced Y4R residues and assessed activation. The in vitro and in silico studies delineated a key Y4R activation interface centered around the conserved C-terminal RXRY-NH2 motif of the peptides and, separately, identified receptor residues with distinct peptide-specific functional effects. Next, we performed an ultra-large library screening (ULLS) and experimentally validated three predicted hits as selective Y4R agonists that engage in a substantial subset of the identified critical receptor contacts. This study demonstrates how GPCR activation interface knowledge can be translated into the discovery of novel small-molecule agonists and outlines a general strategy for advanced GPCR drug discovery.

biochemistry↗

bioRxiv2023

Structural basis of CMKLR1 signaling induced by chemerin9

Chemokine-like receptor 1 (CMKLR1), also known as chemerin receptor 23 (ChemR23) or chemerin receptor 1, is a chemoattractant G protein-coupled receptor (GPCR) that responds to the adipokine chemerin and is highly expressed in innate immune cells, including macrophages and neutrophils. The signaling pathways of CMKLR1 can lead to both pro- and anti-inflammatory effects depending on the ligands and physiological contexts. To understand the molecular mechanisms of CMKLR1 signaling, we determined a high-resolution cryo-electron microscopy (cryo-EM) structure of the CMKLR1-Gi signaling complex with chemerin9, a nanopeptide agonist derived from chemerin, which induced complex phenotypic changes of macrophages in our assays. The cryo-EM structure, together with molecular dynamics simulations and mutagenesis studies, revealed the molecular basis of CMKLR1 signaling by elucidating the interactions at the ligand-binding pocket and the agonist-induced conformational changes. Our results are expected to facilitate the development of small molecule CMKLR1 agonists that mimic the action of chemerin9 to promote the resolution of inflammation.

biophysics↗

bioRxiv2020

Live cell PNA labelling enables erasable fluorescence imaging of membrane proteins

DNA nanotechnology is an emerging field, which promises fascinating opportunities for the manipulation and imaging of proteins on a cell surface. The key to progress in the area is the ability to create the nucleic acid-protein junction in the context of living cells. Here we report a covalent labelling reaction, which installs a biostable peptide nucleic acid (PNA) tag. The reaction proceeds within minutes and is specific for proteins carrying a 2 kDa coiled coil peptide tag. Once installed the PNA label serves as a generic landing platform that enables the recruitment of fluorescent dyes via nucleic acid hybridization. We demonstrate the versatility of this approach by recruiting different fluorophores, assembling multiple fluorophores for increased brightness, and achieving reversible labelling by way of toehold mediated strand displacement. Additionally, we show that labelling can be carried out using two different coiled coil systems, with EGFR and ETBR, on both HEK293 and CHO cells. Finally, we apply the method to monitor internalization of EGFR on CHO cells.

biophysics↗