A Putative Frizzled 7-Targeting Compound Acts as a Firefly Luciferase Inhibitor.

The Frizzled family (FZD) of G protein-coupled receptors regulates WNT signaling mediating proliferative input. Dysregulation of FZD and exaggerated WNT/β-catenin signaling is frequently observed in intestinal cancers. Therefore, it is attractive to develop therapeutics targeting FZD for cancer treatment.

The 75-Year Anniversary of the Department of Physiology and Pharmacology at Karolinska Institutet-Examples of Recent Accomplishments and Future Perspectives.

Karolinska Institutet is a medical university encompassing 21 departments distributed across three departmental or campus groups. Pharmacological research has a long and successful tradition at the institute with a multitude of seminal findings in the areas of neuronal control of vasodilatation, cardiovascular pharmacology, neuropsychopharmacology, receptor pharmacology, and pharmacogenomics that resulted in, among many other recognitions, two Nobel prizes in Physiology and Medicine, one in 1970 to Ulf von Euler for his discovery of the processes involved in storage, release, and inactivation of neurotransmitters and the other in 1982 to Sune Bergström and Bengt Samuelsson for their work on prostaglandins and the discovery of leukotrienes. Pharmacology at Karolinska Institutet has over the last decade been ranked globally among the top 10 according to the QS World University Ranking.

A molecular mechanism to diversify Ca signaling downstream of Gs protein-coupled receptors.

A long-held tenet in inositol-lipid signaling is that cleavage of membrane phosphoinositides by phospholipase Cβ (PLCβ) isozymes to increase cytosolic Ca in living cells is exclusive to Gq- and Gi-sensitive G protein-coupled receptors (GPCRs). Here we extend this central tenet and show that Gs-GPCRs also partake in inositol-lipid signaling and thereby increase cytosolic Ca. By combining CRISPR/Cas9 genome editing to delete Gα, the adenylyl cyclase isoforms 3 and 6, or the PLCβ1-4 isozymes, with pharmacological and genetic inhibition of Gq and G11, we pin down Gs-derived Gβγ as driver of a PLCβ2/3-mediated cytosolic Ca release module.

Class-Wide Analysis of Frizzled-Dishevelled Interactions Using BRET Biosensors Reveals Functional Differences among Receptor Paralogs.

Wingless/Int-1 (WNT) signaling is mediated by WNT binding to 10 Frizzleds (FZD), which propagate the signal inside the cell by interacting with different transducers, most prominently the phosphoprotein Dishevelled (DVL). Despite recent progress, questions about WNT/FZD selectivity and paralog-dependent differences in the FZD/DVL interaction remain unanswered. Here, we present a class-wide analysis of the FZD/DVL interaction using the DEP domain of DVL as a proxy in bioluminescence resonance energy transfer (BRET) techniques.

Structural basis of frizzled 7 activation and allosteric regulation.

Frizzleds (ten paralogs: FZD) belong to the class F of G protein-coupled receptors (GPCRs), which remains poorly understood despite its crucial role in multiple key biological functions including embryonic development, stem cell regulation, and homeostasis in the adult. FZD, one of the most studied members of the family, is more specifically involved in the migration of mesendoderm cells during the development and renewal of intestinal stem cells in adults. Moreover, FZD has been highlighted for its involvement in tumor development predominantly in the gastrointestinal tract.

New Smoothened ligands based on the purine scaffold as potential agents for treating pancreatic cancer.

Aberrant activation of the Hedgehog (Hh) signalling pathway has been associated with the development and progression of pancreatic cancer. For this reason, blockade of Hh pathway by inhibitors targeting the G protein-coupled receptor Smoothened (SMO) has been considered as a therapeutic target for the treatment of this cancer. In our previous work, we obtained a new SMO ligand based on a purine scaffold (compound I), which showed interesting antitumor activity in several cancer cell lines.

International Union of Basic and Clinical Pharmacology CXV: The Class F of G Protein-Coupled Receptors.

The class F of G protein-coupled receptors (GPCRs) consists of 10 Frizzleds (FZD) and Smoothened (SMO). FZDs bind and are activated by secreted lipoglycoproteins of the Wingless/Int-1 (WNT) family, and SMO is indirectly activated by the Hedgehog (Hh) family of morphogens acting on the transmembrane protein Patched. The advance of our understanding of FZDs and SMO as dynamic transmembrane receptors and molecular machines, which emerged during the past 14 years since the first-class F GPCR IUPHAR nomenclature report, justifies an update.

Frizzleds act as dynamic pharmacological entities.

The Frizzled family of transmembrane receptors (FZD) belongs to the class F of G protein-coupled receptors (GPCRs). FZDs bind to and are activated by Wingless/Int1 (WNT) proteins. The WNT/FZD signaling system regulates crucial aspects of developmental biology and stem-cell regulation.

The dark sides of the GPCR tree - research progress on understudied GPCRs.

A large portion of the human GPCRome is still in the dark and understudied, consisting even of entire subfamilies of GPCRs such as odorant receptors, class A and C orphans, adhesion GPCRs, Frizzleds and taste receptors. However, it is undeniable that these GPCRs bring an untapped therapeutic potential that should be explored further. Open questions on these GPCRs span diverse topics such as deorphanisation, the development of tool compounds and tools for studying these GPCRs, as well as understanding basic signalling mechanisms.

Structural and functional insight into the interaction of Clostridioides difficile toxin B and FZD.

The G protein-coupled receptors of the Frizzled (FZD) family, in particular FZD, are receptors that are exploited by Clostridioides difficile toxin B (TcdB), the major virulence factor responsible for pathogenesis associated with Clostridioides difficile infection. We employ a live-cell assay examining the affinity between full-length FZDs and TcdB. Moreover, we present cryoelectron microscopy structures of TcdB alone and in complex with full-length FZD, which reveal that large structural rearrangements of the combined repetitive polypeptide domain are required for interaction with FZDs and other TcdB receptors, constituting a first step for receptor recognition.

Wnt/β-catenin and NFκB signaling synergize to trigger growth factor-free regeneration of adult primary human hepatocytes.

Background And Aims: The liver has a remarkable capacity to regenerate, which is sustained by the ability of hepatocytes to act as facultative stem cells that, while normally quiescent, re-enter the cell cycle after injury. Growth factor signaling is indispensable in rodents, whereas Wnt/β-catenin is not required for effective tissue repair. However, the molecular networks that control human liver regeneration remain unclear.

Pathway selectivity in Frizzleds is achieved by conserved micro-switches defining pathway-determining, active conformations.

The class Frizzled of G protein-coupled receptors (GPCRs), consisting of ten Frizzled (FZD) paralogs and Smoothened, remains one of the most enigmatic GPCR families. This class mediates signaling predominantly through Disheveled (DVL) or heterotrimeric G proteins. However, the mechanisms underlying pathway selection are elusive.

Conformational GPCR BRET Sensors Based on Bioorthogonal Labeling of Noncanonical Amino Acids.

Here we describe the application of genetic code expansion and site-specific incorporation of noncanonical amino acids that serve as anchor points for fluorescent labeling to generate bioluminescence resonance energy transfer (BRET)-based conformational sensors. Using a receptor with an N-terminal NanoLuciferase (Nluc) and a fluorescently labeled noncanonical amino acid in the receptor's extracellular part allows to analyze receptor complex formation, dissociation, and conformational rearrangements over time and in living cells. These BRET sensors can be used to investigate ligand-induced intramolecular (cysteine-rich domain [CRD] dynamics), but also intermolecular (dimer dynamics) receptor rearrangements.

NanoBiT- and NanoBiT/BRET-based assays allow the analysis of binding kinetics of Wnt-3a to endogenous Frizzled 7 in a colorectal cancer model.

Background And Purpose: Wnt binding to Frizzleds (FZD) is a crucial step that leads to the initiation of signalling cascades governing multiple processes during embryonic development, stem cell regulation and adult tissue homeostasis. Recent efforts have enabled us to shed light on Wnt-FZD pharmacology using overexpressed HEK293 cells. However, assessing ligand binding at endogenous receptor expression levels is important due to differential binding behaviour in a native environment.

WNT stimulation induces dynamic conformational changes in the Frizzled-Dishevelled interaction.

Frizzleds (FZDs) are G protein-coupled receptors (GPCRs) that bind to WNT family ligands. FZDs signal through multiple effector proteins, including Dishevelled (DVL), which acts as a hub for several downstream signaling pathways. To understand how WNT binding to FZD stimulates intracellular signaling and influences downstream pathway selectivity, we investigated the dynamic changes in the FZD-DVL2 interaction elicited by WNT-3A and WNT-5A.

Isoforms of GPR35 have distinct extracellular N-termini that allosterically modify receptor-transducer coupling and mediate intracellular pathway bias.

Within the intestine, the human G protein-coupled receptor (GPCR) GPR35 is involved in oncogenic signaling, bacterial infections, and inflammatory bowel disease. GPR35 is known to be expressed as two distinct isoforms that differ only in the length of their extracellular N-termini by 31 amino acids, but detailed insights into their functional differences are lacking. Through gene expression analysis in immune and gastrointestinal cells, we show that these isoforms emerge from distinct promoter usage and alternative splicing.

Prognosis of shoulder pain in those with and without a psychological disorder: A prospective cohort study with a six-month follow-up.

Background: Because shoulder pain can have an unfavorable prognosis, it is important to have a better understanding of factors that may influence recovery.

Objective: To determine the association between recovery from shoulder pain and the presence of depression, anxiety, and pain catastrophizing.

Methods: In a prospective cohort study with a six months follow-up, we included patients visiting an orthopaedic department with shoulder pain.

Biosensing with a scanning planar Yagi-Uda antenna.

We investigate a model bioassay in a liquid environment using a -scanning planar Yagi-Uda antenna, focusing on the fluorescence collection enhancement of ATTO-647N dye conjugated to DNA (deoxyribonucleic acid) molecules. The antenna changes the excitation and the decay rates and, more importantly, the emission pattern of ATTO-647N, resulting in a narrow emission angle (41°) and improved collection efficiency. We efficiently detect immobilized fluorescently-labeled DNA molecules, originating from solutions with DNA concentrations down to 1 nM.

Frizzled BRET sensors based on bioorthogonal labeling of unnatural amino acids reveal WNT-induced dynamics of the cysteine-rich domain.

Frizzleds (FZD) are G protein–coupled receptors containing an extracellular cysteine-rich domain (CRD) binding Wingless/Int-1 lipoglycoproteins (WNTs). Despite the role of WNT/FZD signaling in health and disease, our understanding of how WNT binding is translated into receptor activation and transmembrane signaling remains limited. Current hypotheses dispute the roles for conformational dynamics.

NanoBRET and NanoBiT/BRET-Based Ligand Binding Assays Permit Quantitative Assessment of Small Molecule Ligand Binding to Smoothened.

Smoothened (SMO) is a G protein-coupled receptor (GPCR) that mediates Hedgehog (Hh) signaling. SMO activity is regulated following the binding of Hh to the transmembrane protein Patched. Overactive SMO signaling is oncogenic, and hence this receptor is a target for several marketed drugs.