Biology subjects

Rosenkilde, M. M.

Publications and source records attributed to Rosenkilde, M. M..

9 recordsLinked to original sources

bioRxiv2026

De novo macrocyclic peptide discovery produces potent class A GPCR ligands with diverse pharmacology

G protein-coupled receptors (GPCRs) represent one of the largest protein families of therapeutic importance, as over one third of all currently approved drugs target GPCRs. A growing proportion of GPCR drugs are peptides. However, class A GPCRs (over 80% of clinically studied targets) are underexploited as peptide targets, presumably since their only structured domain is the core, seven-helix, integral membrane fold presenting a limited solvent-exposed surface area. Screening libraries of de novo macrocyclic peptides have allowed for the targeting of otherwise intractable proteins, but their potential to generate selective ligands for class A GPCRs has not been demonstrated. Here, we used random nonstandard peptides integrated discovery (RaPID) to identify de novo macrocyclic peptide ligands targeting the chemokine receptor CXCR4. CXCR4 regulates cell migration, immune surveillance, and inflammation, making it an important therapeutic target for multiple diseases. We discovered novel, potent CXCR4-selective antagonists binding within the orthosteric pocket with nanomolar affinity. The most active peptides effectively inhibited receptor signaling, suppressed chemokine-driven cell migration, and blocked CXCR4-driven HIV entry. Our results show that even the structurally minimal class A GPCRs are viable targets for de novo cyclic peptide discovery, highlighting the potential for uncovering ligands towards other members of the GPCR superfamily.

pharmacology and toxicology↗

bioRxiv2026

Targeting the Oxysterol Receptor GPR183 to Mitigate Fibrogenesis in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal lung disease with a median survival of 3-5 years after diagnosis. Current antifibrotic therapies slow disease progression, but do not halt or reverse fibrosis, underscoring the need for new therapies. We identified a dysregulated oxysterol-GPR183 axis as a driver of IPF. Oxidized cholesterols were elevated in lungs from IPF patients, with myofibroblasts representing the dominant source of 7,25-hydroxycholesterol (7,25-OHC), the endogenous high affinity ligand for the oxysterol-sensing receptor GPR183. IPF patients had increased GPR183 expression in interstitial and monocyte-like macrophages compared to controls. In a bleomycin-induced model of pulmonary fibrosis genetic deletion of GPR183 reduced disease severity characterized by reduced fibrosis, inflammation, and accumulation of macrophages and myofibroblasts. Pharmacological inhibition of GPR183 with the antagonist NIBR189 attenuated fibrosis when administered preventatively from day 1-7 after bleomycin exposure. Notably, therapeutic treatment with the GPR183 antagonist after commencement of fibrosis development at day 10 post-bleomycin also significantly reduced fibrotic pathology, achieving efficacy comparable to the approved antifibrotic nintedanib. However, the GPR183 antagonist was more potent in reducing inflammation and myofibroblast activation compared to nintedanib. Together, these findings identify an oxysterol-GPR183 signaling axis that contributes to pulmonary fibrogenesis and provide a strong preclinical rationale for targeting GPR183 as a novel therapeutic strategy for IPF. One Sentence SummaryTargeting GPR183 reduced lung fibrosis and inflammation in a preclinical model, supporting GPR183 as a promising new therapy.

immunology↗

bioRxiv2026

Development of Potent G Protein Pathway-Biased GPR183 Agonists

GPR183 is an oxysterol-sensing GPCR predominantly expressed in lymphoid organs and tissues. Activation of the receptor by oxysterol 7,25-OHC leads to Gi protein-mediated signaling as well as {beta}-arrestin2 recruitment. GPR183/oxysterol signaling modulates localization of lymphoid cells, consequently the receptor is associated with several inflammation-associated diseases and is an interesting potential drug target. Previously, we reported the discovery of moderately potent G protein-biased partial agonists for GPR183 from a virtual screening based on the scaffold of the antagonist NIBR189. Herein, we present the detailed structure-activity investigations and optimizations, which led to the identification of full agonists for GPR183 with complete bias for Gi protein signaling and low nanomolar potency, including 63 (TUG-2604) with potency and efficacy similar to 7,25-OHC. Notably, 63 was unable to induce migration of human dendritic cells but inhibited migration induced by 7,25-OHC. This compound will be valuable for further explorations of the signaling-specific function and drug target potential of GPR183.

pharmacology and toxicology↗

bioRxiv2026

A quantitative imaging framework reveals density-dependent GPCR oligomerization and organization in living cells

GPCR oligomerization has been reported for decades, yet its extent and functional relevance in living cells remain unresolved because existing approaches, often done in bulk, are poorly account for local receptor density, a major determinant of intermolecular interactions. Here, we establish a generic quantitative imaging framework that links spatially resolved FRET measurements describing protein oligomerization to local membrane protein in living cells. Using automated high-throughput analysis of fluorescence images, the method generates large density-resolved datasets that enable direct quantification of receptor oligomerization parameters, including apparent affinity, oligomerization state, and monomer/dimer populations at the submicrometer scale. Applied to class A GPCRs in HEK293 cells, the approach reveals receptor-specific density-dependent equilibria between monomers and dimers over physiologically relevant expression ranges, with no evidence for stable higher-order oligomers under basal conditions. The receptors studied exhibit distinct apparent affinities for dimerization, ranging from predominantly monomeric to dynamic monomer-dimer equilibria, indicating that local membrane density strongly influences receptor organization and that it is receptor dependent. The agreement between our measurements and low-density single-molecule studies further suggests that previously reported higher-order oligomers may partly reflect density-driven receptor proximity effects. By bridging single-molecule and ensemble measurements within a unified quantitative framework, this work reconciles conflicting observations in the GPCR oligomerization literature and provides a broadly applicable strategy for investigating membrane protein organization in living cells. SignificanceGPCR oligomerization in living cells is strongly influenced by the local protein density, yet most approaches do not quantitatively account for this parameter. Here, we introduce a quantitative high-throughput imaging framework that directly relates membrane protein local density to local oligomerization state in living cells. Applied to distinct GPCRs over physiologically relevant density ranges, the method reveals distinct density-dependent monomer-dimer equilibrium and apparent affinities for self-association. These results help reconcile longstanding discrepancies, where distinct oligomerization states have been measured depending on experimental conditions. More broadly, this work establishes local membrane protein density as a key determinant of membrane protein organization, and provides a quantitative framework applicable to membrane protein complexes in their native cellular context.

biophysics↗

bioRxiv2024

The SH Protein of Mumps Virus is a Druggable Pentameric Viroporin

Viral infections are on the rise and drugs targeting viral proteins are needed. Viroporins constitute a growing group of virus-encoded transmembrane oligomeric proteins that allow passage of small molecules across the membrane. Despite sparsity in viroporin structures, recent work has revealed diversity in both the number of transmembrane helices and oligomeric states. Here we provide evidence that the small hydrophobic protein (SH) from mumps virus is a pentameric viroporin. From extensive biophysical data, a HADDOCK model of full-length SH shows its intracellular C-terminal region to form an extended structure crucial to stabilization of the pentamer. Heterologous expression of wild type SH and variants in Xenopus laevis oocytes reveals the viroporin as a chloride channel, facilitated by conserved hydroxyl-carrying residues lining the pore. The channel function of SH is inhibited by the small-molecule BIT225, highlighting the potential for antiviral targeting through SH.

biophysics↗

bioRxiv2022

GIP receptor reduces osteoclast activity and improves osteoblast survival by activating multiple signaling pathways

Bone is a dynamic tissue that is remodeled throughout life by bone resorbing osteoclasts and bone forming osteoblasts, to adapt to physiological or mechanical demands. These processes are impaired in osteoporosis, and understanding how bone remodeling is regulated could improve anti-osteoporotic treatments. Clinical investigations show that short-term treatment with glucose-dependent insulinotropic polypeptide (GIP) acutely decreases serum markers of bone resorption and may increase bone formation. However, evidence for direct effects of GIP intracellular signaling and functions in mature human osteoclasts and osteoblasts have not been investigated. We report that the GIP receptor (GIPR) is robustly expressed in mature human osteoclasts. Exposure of osteoclasts to GIP inhibits osteoclastogenesis, delays bone resorption, and increases osteoclast apoptosis by acting upon multiple signaling pathways (cAMP, Src, Akt, calcium, p38) to impair nuclear translocation of nuclear factor of activated T cells 1 (NFATc1) and nuclear factor-{kappa}B (NF{kappa}B). Human osteoblasts also express GIPR, and GIP improves osteoblast survival via cAMP and Akt-mediated pathways. GIP treatment of co-cultures of osteoclasts and osteoblasts also decreased bone resorption. Antagonizing GIPR with GIP(3-30)NH2 abolished the effects of GIP on osteoclasts and osteoblasts. This study demonstrates that GIP inhibits bone resorption and improves survival of human osteoblasts, which could increase bone mass and strength, supporting clinical investigations of the effect of GIP on bone. Moreover, this study demonstrates that GIPR agonism could be beneficial in the treatment of disorders of bone remodeling, such as osteoporosis. One-sentence SummaryGIP acts directly on bone cells to regulate bone remodeling

cell biology↗

bioRxiv2022

Oxysterols drive inflammation via GPR183 during influenza virus and SARS-CoV-2 infection

RationaleSevere viral respiratory infections are often characterized by extensive myeloid cell infiltration and activation and persistent lung tissue injury. However, the immunological mechanisms driving excessive inflammation in the lung remain elusive. ObjectivesTo identify the mechanisms that drive immune cell recruitment in the lung during viral respiratory infections and identify novel drug targets to reduce inflammation and disease severity. MethodsPreclinical murine models of influenza virus and SARS-CoV-2 infection. ResultsOxidized cholesterols and the oxysterol-sensing receptor GPR183 were identified as drivers of monocyte-macrophage infiltration to the lung during influenza virus (IAV) and SARS-CoV-2 infections. Both IAV and SARS-CoV-2 infections upregulated the enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) in the lung, resulting in local production of the oxidized cholesterols 25-hydroxycholesterol and 7,25-dihydroxycholesterol (7,25-OHC). Loss-of-function mutation of GPR183, or treatment with a GPR183 antagonist, reduced macrophage infiltration and inflammatory cytokine production in the lungs of IAV- or SARS-CoV-2-infected mice. The GPR183 antagonist also significantly attenuated the severity of SARS-CoV-2 infection by reducing weight loss and viral loads. ConclusionThis study demonstrates that oxysterols drive inflammation in the lung and provides the first preclinical evidence for therapeutic benefit of targeting GPR183 during severe viral respiratory infections. Author SummaryViral infections trigger oxysterol production in the lung, attracting macrophages via GPR183. Blocking GPR183 reduced inflammation and disease severity in SARS-CoV-2 infection, making GPR183 a putative target for therapeutic intervention.

immunology↗

bioRxiv2022

A blunted GPR183/oxysterol axis during dysglycemia results in delayed recruitment of macrophages to the lung during M. tuberculosis infection

We previously reported that the oxidised cholesterol-sensing receptor GPR183 is significantly downregulated in blood from tuberculosis (TB) patients with diabetes compared to TB patients without co-morbidities and that lower GPR183 expression in blood is associated with more severe pulmonary TB on chest-x-ray consistent with observations in dysglycemic mice. To further elucidate the role of this receptor and its endogenous high affinity agonist 7,25-di-hydroxycholesterol (7,25-OHC) in the lung, we studied high fat diet (HFD)-induced dysglycemic mice infected with M.tuberculosis. We found that the 7,25-OHC-producing enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) were highly upregulated upon M. tuberculosis infection in the lungs of normoglycemic mice, and this was associated with increased expression of GPR183 indicative of effective recruitment of GPR183-expressing immune cells to the site of infection. We demonstrated that CYP7B1 was predominantly expressed by macrophages in the centre of TB granulomas. Expression of CYP7B1 was significantly blunted in lungs from HFD-fed dysglycemic animals and this coincided with delayed recruitment of macrophages to the lung during early infection and more severe lung pathology. GPR183 deficient mice similarly had reduced macrophage recruitment during early infection demonstrating a requirement of the GPR183/oxysterol axis for macrophage infiltration into the lung in TB. Together our data demonstrate that oxidised cholesterols and GPR183 play an important role in positioning macrophages to the site of M. tuberculosis infection and that this is impaired by HFD-induced dysglycemia, adding a mechanistic explanation to the poorer TB outcomes in patients with diabetes.

immunology↗

bioRxiv2020

GPR183 regulates interferons and bacterial growth during Mycobacterium tuberculosis infection: interaction with type 2 diabetes and TB disease severity

Oxidized cholesterols have emerged as important signaling molecules of immune function, but little is known about the role of these oxysterols during mycobacterial infections. We found that expression of the oxysterol-receptor GPR183 was reduced in blood from patients with tuberculosis (TB) and type 2 diabetes (T2D) compared to TB patients without T2D and was associated with TB disease severity on chest x-ray. GPR183 activation by 7,25-hydroxycholesterol (7,25-OHC) reduced growth of Mycobacterium tuberculosis (Mtb) and Mycobacterium bovis BCG in primary human monocytes, an effect abrogated by the GPR183 antagonist GSK682753. Growth inhibition was associated with reduced IFN-{beta} and IL-10 expression and enhanced autophagy. Mice lacking GPR183 had significantly increased lung Mtb burden and dysregulated IFNs during early infection. Together, our data demonstrate that GPR183 is an important regulator of intracellular mycobacterial growth and interferons during mycobacterial infection. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/203398v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@76c86dorg.highwire.dtl.DTLVardef@60a3bcorg.highwire.dtl.DTLVardef@9dc233org.highwire.dtl.DTLVardef@138db01_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗