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October 2022 Coincident Regulation of PLCβ Signaling by Gq-Coupled and μOpioid Receptors Opposes Opioid- Mediated Antinociception "Pain management is a significant problem worldwide. The current frontline approach for pain-management is the use of opioid analgesics. The primary analgesic target of opioids is the μ-opioid receptor (MOR). Deletion of phospholipase Cβ3 (PLCβ3), or selective inhibition of Gβγ regulation of PLCβ3, enhances the potency of the antinociceptive effects of morphine suggesting a novel strategy for achieving opioid sparing effects. Here we investigated a potential mechanism for regulation of PLC signaling downstream of MOR in HEK293 cells and found that MOR alone could not stimulate PLC, but rather required a coincident signal from a Gq coupled receptor. Knockout of PLCβ3, or pharmacological inhibition of its upstream regulators, Gβγ or Gq, ex vivo in periaqueductal gray (PAG) slices increased the potency of the selective MOR agonist DAMGO in inhibiting presynaptic GABA release. Finally, inhibition of Gq-GPCR coupling in mice enhanced the antinociceptive effects of morphine. These data support a model where Gq and Gβγ-dependent signaling cooperatively regulate PLC activation to decrease MOR-dependent antinociceptive potency. Ultimately this could lead to identification of new non-MOR targets that would allow for lower dose utilization of opioid analgesics. " Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Newsletter HERE

October 2022 GPR125 (ADGRA3) is an autocleavable adhesion GPCR that traffics with Dlg1 to the basolateral membrane and regulates epithelial apicobasal polarity "The adhesion family of G protein-coupled receptors (GPCRs) is defined by an N-terminal large extracellular region that contains various adhesion-related domains and a highly-conserved GPCR-autoproteolysis-inducing (GAIN) domain, the latter of which is located immediately before a canonical seven-transmembrane domain. These receptors are expressed widely and involved in various functions including development, angiogenesis, synapse formation, and tumorigenesis. GPR125 (ADGRA3), an orphan adhesion GPCR, has been shown to modulate planar cell polarity in gastrulating zebrafish, but its biochemical properties and role in mammalian cells have remained largely unknown. Here, we show that human GPR125 likely undergoes cis-autoproteolysis when expressed in canine kidney epithelial MDCK cells and human embryonic kidney HEK293 cells. The cleavage appears to occur at an atypical GPCR proteolysis site within the GAIN domain during an early stage of receptor biosynthesis. The products, i.e., the N-terminal and C-terminal fragments, seem to remain associated after self-proteolysis, as observed in other adhesion GPCRs. Furthermore, in polarized MDCK cells, GPR125 is exclusively recruited to the basolateral domain of the plasma membrane. The recruitment likely requires the C-terminal PDZ-domain-binding motif of GPR125 and its interaction with the cell polarity protein Dlg1. Knockdown of GPR125 as well as that of Dlg1 results in formation of aberrant cysts with multiple lumens in Matrigel 3D culture of MDCK cells. Consistent with the multilumen phenotype, mitotic spindles are incorrectly oriented during cystogenesis in GPR125-KO MDCK cells. Thus, the basolateral protein GPR125, an autocleavable adhesion GPCR, appears to play a crucial role in apicobasal polarization in epithelial cells." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the newsletter HERE

November 2022 "Neuropeptides produce robust effects on behavior across species, and recent research has benefited from advances in high-resolution techniques to investigate peptidergic transmission and expression throughout the brain in model systems. Neuropeptides exhibit distinct characteristics which includes their post-translational processing, release from dense core vesicles, and ability to activate G-protein-coupled receptors (GPCRs). These complex properties have driven the need for development of specialized tools that can sense neuropeptide expression, cell activity, and release. Current research has focused on isolating when and how neuropeptide transmission occurs, as well as the conditions in which neuropeptides directly mediate physiological and adaptive behavioral states. Here we describe the current technological landscape in which the field is operating to decode key questions regarding these dynamic neuromodulators." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

November 2022 Deciphering the signaling mechanisms of β-arrestin1 and β-arrestin2 in regulation of cancer cell cycle and metastasis "β-Arrestins are ubiquitously expressed intracellular proteins with many functions which interact directly and indirectly with a wide number of cellular partners and mediate downstream signaling. Originally, β-arrestins were identified for their contribution to GPCR desensitization to agonist-mediated activation, followed by receptor endocytosis and ubiquitylation. However, current investigations have now recognized that in addition to GPCR arresting (hence the name arrestin). β-Arrestins are adaptor proteins that control the recruitment, activation, and scaffolding of numerous cytoplasmic signaling complexes and assist in G-protein receptor signaling, thus bringing them into close proximity. They have participated in various cellular processes such as cell proliferation, migration, apoptosis, and transcription via canonical and noncanonical pathways. Despite their significant recognition in several physiological processes, these activities are also involved in the onset and progression of various cancers. This review delivers a concise overview of the role of β-arrestins with a primary emphasis on the signaling processes which underlie the mechanism of β-arrestins in the onset of cancer. Understanding these processes has important implications for understanding the therapeutic intervention and treatment of cancer in the future." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

November 2022 "Recently determined structures of class C G protein-coupled receptors (GPCRs) revealed the location of allosteric binding sites and opened new opportunities for the discovery of novel modulators. In this work, molecular docking screens for allosteric modulators targeting the metabotropic glutamate receptor 5 (mGlu5) were performed. The mGlu5 receptor is activated by the main excitatory neurotransmitter of the nervous central system, L-glutamate, and mGlu5 receptor activity can be allosterically modulated by negative or positive allosteric modulators. The mGlu5 receptor is a promising target for the treatment of psychiatric and neurodegenerative diseases, and several allosteric modulators of this GPCR have been evaluated in clinical trials. Chemical libraries containing fragment- (1.6 million molecules) and lead-like (4.6 million molecules) compounds were docked to an allosteric binding site of mGlu5 identified in X-ray crystal structures. Among the top-ranked compounds, 59 fragments and 59 lead-like compounds were selected for experimental evaluation. Of these, four fragment- and seven lead-like compounds were confirmed to bind to the allosteric site with affinities ranging from 0.43 to 8.6 μM, corresponding to a hit rate of 9%. The four compounds with the highest affinities were demonstrated to be negative allosteric modulators of mGlu5 signaling in functional assays. The results demonstrate that virtual screens of fragment- and lead-like chemical libraries have complementary advantages and illustrate how access to high-resolution structures of GPCRs in complex with allosteric modulators can accelerate lead discovery." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

November 2022 "Adhesion G-protein-coupled receptors (aGPCRs) play key roles in a diversity of physiologies. A hallmark of aGPCR activation is the removal of the inhibitory GAIN domain and the dipping of the cleaved stalk peptide into the ligand-binding pocket of receptors; however, the detailed mechanism remains obscure. Here, we present cryoelectron microscopy (cryo-EM) structures of ADGRL3 in complex with Gq, Gs, Gi, and G12. The structures reveal unique ligand-engaging mode, distinctive activation conformation, and key mechanisms of aGPCR activation. The structures also reveal the uncharted structural information of GPCR/G12 coupling. A comparison of Gq, Gs, Gi, and G12 engagements with ADGRL3 reveals the key determinant of G-protein coupling on the far end of αH5 of Gα. A detailed analysis of the engagements allows us to design mutations that specifically enhance one pathway over others. Taken together, our study lays the groundwork for understanding aGPCR activation and G-protein-coupling selectivity." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

November 2022 "Despite the growing number of G protein-coupled receptor (GPCR) structures, only 39 structures have been cocrystallized with allosteric inhibitors. These structures have been studied by protein mapping using the FTMap server, which determines the clustering of small organic probe molecules distributed on the protein surface. The method has found druggable sites overlapping with the cocrystallized allosteric ligands in 21 GPCR structures. Mapping of Alphafold2 generated models of these proteins confirms that the same sites can be identified without the presence of bound ligands. We then mapped the 394 GPCR X-ray structures available at the time of the analysis (September 2020). Results show that for each of the 21 structures with bound ligands there exist many other GPCRs that have a strong binding hot spot at the same location, suggesting potential allosteric sites in a large variety of GPCRs. These sites cluster at nine distinct locations, and each can be found in many different proteins. However, ligands binding at the same location generally show little or no similarity, and the amino acid residues interacting with these ligands also differ. Results confirm the possibility of specifically targeting these sites across GPCRs for allosteric modulation and help to identify the most likely binding sites among the limited number of potential locations." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

November 2022 "Dimerization of beta 2-adrenergic receptor (β2-AR) has been observed across various physiologies. However, the function of dimeric β2-AR is still elusive. Here, we revealed that dimerization of β2-AR is responsible for the constitutive activity of β2-AR generating inverse agonism. Using a co-immunoimmobilization assay, we found that transient β2-AR dimers exist in a resting state, and the dimer was disrupted by the inverse agonists. A Gαs preferentially interacts with dimeric β2-AR, but not monomeric β2-AR, in a resting state, resulting in the production of a resting cAMP level. The formation of β2-AR dimers requires cholesterol on the plasma membrane. The cholesterol did not interfere with the agonist-induced activation of monomeric β2-AR, unlike the inverse agonists, implying that the cholesterol is a specific factor regulating the dimerization of β2-AR. Our model not only shows the function of dimeric β2-AR but also provides a molecular insight into the mechanism of the inverse agonism of β2-AR." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter HERE

October 2022 β-arrestin1 and 2 exhibit distinct phosphorylation-dependent conformations when coupling to the same GPCR in living cells "β-arrestins mediate regulatory processes for over 800 different G protein-coupled receptors (GPCRs) by adopting specific conformations that result from the geometry of the GPCR-β-arrestin complex. However, whether β-arrestin1 and 2 respond differently for binding to the same GPCR is still unknown. Employing GRK knockout cells and β-arrestins lacking the finger-loop-region, we show that the two isoforms prefer to associate with the active parathyroid hormone 1 receptor (PTH1R) in different complex configurations ("hanging" and "core"). Furthermore, the utilisation of advanced NanoLuc/FlAsH-based biosensors reveals distinct conformational signatures of β-arrestin1 and 2 when bound to active PTH1R (P-R*). Moreover, we assess β-arrestin conformational changes that are induced specifically by proximal and distal C-terminal phosphorylation and in the absence of GPCR kinases (GRKs) (R*). Here, we show differences between conformational changes that are induced by P-R* or R* receptor states and further disclose the impact of site-specific GPCR phosphorylation on arrestin-coupling and function." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter

September 2022 "Sound is converted by hair cells in the cochlea into electrical signals, which are transmitted by spiral ganglion neurons (SGNs) and heard by the auditory cortex. G protein-coupled receptors (GPCRs) are crucial receptors that regulate a wide range of physiological functions in different organ and tissues. The research of GPCRs in the cochlea is essential for the understanding of the cochlea development, hearing disorders, and the treatment for hearing loss. Recently, several GPCRs have been found to play important roles in the cochlea. Frizzleds and Lgrs are dominant GPCRs that regulate stem cell self-renew abilities. Moreover, Frizzleds and Celsrs have been demonstrated to play core roles in the modulation of cochlear planar cell polarity (PCP). In addition, hearing loss can be caused by mutations of certain GPCRs, such as Vlgr1, Gpr156, S1P2, and Gpr126. And A1, A2A, and CB2 activation by agonists has protective functions on noise- or drug-induced hearing loss. Here, we review the key findings of GPCR in the cochlea and discuss the role of GPCR in the cochlea, such as stem cell fate, PCP, hearing loss, and hearing protection." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter

October 2022 Dimerization of β2-adrenergic receptor is responsible for the constitutive activity subjected to inverse agonism "Dimerization of beta 2-adrenergic receptor (β2-AR) has been observed across various physiologies. However, the function of dimeric β2-AR is still elusive. Here, we revealed that dimerization of β2-AR is responsible for the constitutive activity of β2-AR generating inverse agonism. Using a co-immunoimmobilization assay, we found that transient β2-AR dimers exist in a resting state, and the dimer was disrupted by the inverse agonists. A Gαs preferentially interacts with dimeric β2-AR, but not monomeric β2-AR, in a resting state, resulting in the production of a resting cAMP level. The formation of β2-AR dimers requires cholesterol on the plasma membrane. The cholesterol did not interfere with the agonist-induced activation of monomeric β2-AR, unlike the inverse agonists, implying that the cholesterol is a specific factor regulating the dimerization of β2-AR. Our model not only shows the function of dimeric β2-AR but also provides a molecular insight into the mechanism of the inverse agonism of β2-AR." Read more at the source #DrGPCR #GPCR #IndustryNews Subscribe to the Dr. GPCR Newsletter

August 2022 GPCRs steer G i and G s selectivity via TM5-TM6 switches as revealed by structures of serotonin receptors "Serotonin (or 5-hydroxytryptamine, 5-HT) is an important neurotransmitter that activates 12 different G protein-coupled receptors (GPCRs) through selective coupling of Gs, Gi, or Gq proteins. The structural basis for G protein subtype selectivity by these GPCRs remains elusive. Here, we report the structures of the serotonin receptors 5-HT4, 5-HT6, and 5-HT7 with Gs, and 5-HT4 with Gi1. The structures reveal that transmembrane helices TM5 and TM6 alternate lengths as a macro-switch to determine receptor's selectivity for Gs and Gi, respectively. We find that the macro-switch by the TM5-TM6 length is shared by class A GPCR-G protein structures. Furthermore, we discover specific residues within TM5 and TM6 that function as micro-switches to form specific interactions with Gs or Gi. Together, these results present a common mechanism of Gs versus Gi protein coupling selectivity or promiscuity by class A GPCRs and extend the basis of ligand recognition at serotonin receptors." Read more at the source #DrGPCR #GPCR #IndustryNews

August 2022 "As the only member of the CX3C chemokine receptor subfamily, CX3CR1 binds to its sole endogenous ligand CX3CL1, which shows notable potential as a therapeutic target in atherosclerosis, cancer, and neuropathy. However, the drug development of CX3CR1 is hampered partially by the lack of structural information. Here, we present two cryo-electron microscopy structures of CX3CR1-Gi1 complexes in ligand-free and CX3CL1-bound states at 2.8- and 3.4-Å resolution, respectively. Together with functional data, the structures reveal the key factors that govern the recognition of CX3CL1 by both CX3CR1 and US28. A much smaller conformational change of helix VI upon activation than previously solved class A GPCR-Gi complex structures is observed in CX3CR1, which may correlate with three cholesterol molecules that play essential roles in conformation stabilization and signaling transduction. Thus, our data deepen the understanding of cholesterol modulation in GPCR (G protein-coupled receptor) signaling and provide insights into the diversity of G protein coupling." Read more at the source #DrGPCR #GPCR #IndustryNews

September 2022 "Pregnant and lactating women have been discouraged from using cannabis by Health Canada. However, the increasing rate of cannabis use among pregnant women has presented an urgent need to investigate its physiological effects during the perinatal period. During pregnancy, the mammary gland (MG) undergoes remodeling, which involves alveolar differentiation of mammary epithelial cells (MECs), which is essential for breast milk production and secretion. Limited evidence has been reported on the impact of cannabis or its components, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), on MG development or MEC differentiation. In this study, we investigated the effects of THC and CBD on the differentiation of MECs by assessing changes in cellular viability, lipid accumulation, and gene and protein expression of major milk protein and lipid synthesizing markers. using the HC11 cells as a model. We hypothesized that THC and CBD will negatively impact the synthesis of milk proteins and lipids, as well as lipid markers in HC11 cells. Our results demonstrated that THC and CBD reduced cellular viability at concentrations above 30μM and 20μM, respectively. Relative to control, 10μM THC and 10μM CBD reduced mRNA levels of milk proteins (CSN2 and WAP), lipid synthesizing and glucose transport markers (GLUT 1, HK2, FASN, FABP4, PLIN2 and LPL), as well as whey acidic protein and lipid levels. In addition, co-treatment of a CB2 antagonist with THC, and a CB2 agonist with CBD, reversed the impact of THC and CBD on the mRNA levels of key markers, respectively. In conclusion, 10μM THC and CBD altered the differentiation of HC11 cells, in part via the CB2 receptor." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 High hedgehog signaling is transduced by a multikinase-dependent switch controlling the apico-basal distribution of the GPCR smoothened "The oncogenic G-protein-coupled receptor (GPCR) Smoothened (SMO) is a key transducer of the hedgehog (HH) morphogen, which plays an essential role in the patterning of epithelial structures. Here, we examine how HH controls SMO subcellular localization and activity in a polarized epithelium using the Drosophila wing imaginal disc as a model. We provide evidence that HH promotes the stabilization of SMO by switching its fate after endocytosis toward recycling. This effect involves the sequential and additive action of protein kinase A, casein kinase I, and the Fused (FU) kinase. Moreover, in the presence of very high levels of HH, the second effect of FU leads to the local enrichment of SMO in the most basal domain of the cell membrane. Together, these results link the morphogenetic effects of HH to the apico-basal distribution of SMO and provide a novel mechanism for the regulation of a GPCR." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "Arrestins interact with G protein-coupled receptors (GPCRs) to stop G protein activation and to initiate key signaling pathways. Recent structural studies shed light on the molecular mechanisms involved in GPCR-arrestin coupling, but whether this process is conserved among GPCRs is poorly understood. Here, we report the cryo-electron microscopy active structure of the wild-type arginine-vasopressin V2 receptor (V2R) in complex with β-arrestin1. It reveals an atypical position of β-arrestin1 compared to previously described GPCR-arrestin assemblies, associated with an original V2R/β-arrestin1 interface involving all receptor intracellular loops. Phosphorylated sites of the V2R carboxyl terminus are clearly identified and interact extensively with the β-arrestin1 N-lobe, in agreement with structural data obtained with chimeric or synthetic systems. Overall, these findings highlight a notable structural variability among GPCR-arrestin signaling complexes." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Dual loss of regulator of G protein signaling 2 and 5 exacerbates ventricular myocyte arrhythmias and disrupts the fine-tuning of Gi/o signaling "Aims: Cardiac contractility, essential to maintaining proper cardiac output and circulation, is regulated by G protein-coupled receptor (GPCR) signaling. Previously, the absence of regulator of G protein signaling (RGS) 2 and 5, separately, was shown to cause G protein dysregulation, contributing to modest blood pressure elevation and exaggerated cardiac hypertrophic response to pressure-overload. Whether RGS2 and 5 redundantly control G protein signaling to maintain cardiovascular homeostasis is unknown. Here we examined how the dual absence of RGS2 and 5 (Rgs2/5 dbKO) affects blood pressure and cardiac structure and function." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "G protein-coupled receptors (GPCRs) are important drug targets characterized by a canonical seven transmembrane (TM) helix architecture. Recent advances in X-ray crystallography and cryo-EM have resulted in a wealth of GPCR structures that have been used in drug design and formed the basis for mechanistic activation hypotheses. Here, ensemble refinement (ER) of crystallographic structures is applied to explore the impact of binding of agonists and antagonist/inverse agonists to selected structures of cannabinoid receptor 1 (CB1R), β2 adrenergic receptor (β2 AR) and A2A adenosine receptor (A2A AR). " Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Increased Anxiety-like Behaviors in Adgra1-/- Male But Not Female Mice are Attributable to Elevated Neuron Dendrite Density, Upregulated PSD95 Expression, and Abnormal Activation of the PI3K/AKT/GSK-3β and MEK/ERK Pathways "Adhesion G protein-coupled receptor A1 (ADGRA1) belongs to the G protein-coupled receptor (GPCR) family, and its physiological function remains largely unknown. We found that Adgra1 is highly and exclusively expressed in the brain, suggesting that Adgra1 may be involved in the regulation of neurological behaviors including anxiety, depression, learning and memory. To this end, we comprehensively analyzed the potential role of ADGRA1 in the neurobehaviors of mice by comparing Adgra1-/- and their wild-type (wt) littermates. We found that Adgra1-/- male but not female mice exhibited elevated anxiety levels in the open field, elevated plus maze, and light-dark box tests, with normal depression levels in the tail-suspension and forced-swim tests, and comparable learning and memory abilities in the Morris water maze, Y maze, fear condition, and step-down avoidance tests. Further studies showed that ADGRA1 deficiency resulted in higher dendritic branching complexity and spine density as evidenced by elevated expression levels of SYN and PSD95 in amygdalae of male mice. Finally, we found that PI3K/AKT/GSK-3β and MEK/ERK in amygdalae of Adgra1-deficient male mice were aberrantly activated when compared to wt male mice. Together, our findings reveal an important suppressive role of ADGRA1 in anxiety control and synaptic function by regulating the PI3K/AKT/GSK-3β and MEK/ERK pathways in amygdalae of male mice, implicating a potential, therapeutic application in novel anti-anxiety drug development." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "Visual phototransduction is the most extensively studied G protein-coupled receptor (GPCR) signaling pathway because of its quantifiable stimulus, non-redundancy of genes, and immense importance in vision. We summarize recent discoveries that have advanced our understanding of rod outer segment (ROS) morphology and the pathological basis of retinal diseases. We have combined recently published cryo-electron tomography (cryo-ET) data on the ROS with structural knowledge on individual proteins to define the precise spatial limitations under which phototransduction occurs. Although hypothetical, the reconstruction of the rod phototransduction system highlights the potential roles of phosphodiesterase 6 (PDE6) and guanylate cyclases (GCs) in maintaining the spacing between ROS discs, suggesting a plausible mechanism by which intrinsic optical signals are generated in the retina." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Case Report of a Juvenile Patient with Autism Spectrum Disorder with a Novel Combination of Copy Number Variants in ADGRL3 (LPHN3) and Two Pseudogenes "We report the finding of two copy number variants (CNVs) in a 12-year-old boy presenting both with autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD). Clinical features included aggressive behavior, mood instability, suicidal statements, repetitive and restrictive behavior, sensitivity to noise, learning problems and dyslexia, though no intellectual disability was present. Using array-based comparative genomic hybridization (array-CGH), we identified two CNVs, both triplex duplications of 324 kb on 3p26.3, and 284 kb on 4q13.1, respectively. One of the CNVs is located on chromosome 4q13.1 in the region of the gene encoding for adhesion G protein-coupled receptor L3 (ADGRL3, former name: latrophilin-3, LPHN3), the other on chromosome 3p26.3 in the region of the two pseudogenes AC090043.1 and RPL23AP39. The patient described in the present study showed increased symptoms under methylphenidate treatment but responded positively to 3 mg per day of the atypical neuroleptic drug aripiprazole. To our knowledge, this is the first report of a CNV in the ADGRL3 gene and its first association with ASD in humans." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Discovery and In Vivo Evaluation of ACT-660602: A Potent and Selective Antagonist of the Chemokine Receptor CXCR3 for Autoimmune Diseases "The chemokine receptor CXCR3 is a seven-transmembrane G-protein-coupled receptor (GPCR) involved in various pathologies, in particular autoimmune diseases. It is activated by the three chemokine ligands CXCL9, CXCL10, and CXCL11 and enables the recruitment of immune cell subsets leading to damage of inflamed tissues. Starting from a high-throughput screening hit, we describe the iterative optimization of a chemical series culminating in the discovery of the selective CXCR3 antagonist ACT-660602 (9j). The careful structural modifications during the lead optimization phase led to a compound with high biological potency in inhibiting cell migration together with improvements of the metabolic stability and hERG issue. In a LPS-induced lung inflammation model in mice, ACT-660602 led to significantly reduced recruitment of the CXCR3+ CD8+ T cell in the bronchoalveolar lavage compartment when administered orally at a dose of 30 mg/kg." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Recurrent hypoglycemia increases hepatic gluconeogenesis without affecting glycogen metabolism or systemic lipolysis in rat "Introduction: Recurrent hypoglycemia (RH) impairs secretion of counterregulatory hormones. Whether and how RH affects responses within metabolically important peripheral organs to counterregulatory hormones are poorly understood. Objective: To study the effects of RH on metabolic pathways associated with glucose counterregulation within liver, white adipose tissue and skeletal muscle. Methods: Using a widely adopted rodent model of 3-day recurrent hypoglycemia, we first checked expression of counterregulatory hormone G-protein coupled receptors (GPCRs), their inhibitory regulators and downstream enzymes catalyzing glycogen metabolism, gluconeogenesis and lipolysis by qPCR and western blot. Then, we examined epinephrine-induced phosphorylation of PKA substrates to validate adrenergic sensitivity in each organ. Next, we measured hepatic and skeletal glycogen content, degree of breakdown by epinephrine and abundance of phosphorylated glycogen phosphorylase under hypoglycemia and that of phosphorylated glycogen synthase during recovery to evaluate glycogen turnover. Further, we performed pyruvate and lactate tolerance tests to assess gluconeogenesis. Additionally, we measured circulating FFA and glycerol to check lipolysis. The abovementioned studies were repeated in streptozotocin-induced diabetic rat model. Finally, we conducted epinephrine tolerance test to investigate systemic glycemic excursions to counterregulatory hormones. Saline-injected rats served as controls." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "Understanding the dopaminergic system is a priority in neurobiology and neuropharmacology. Dopamine receptors are involved in the modulation of fundamental physiological functions, and dysregulation of dopaminergic transmission is associated with major neurological disorders. However, the available tools to dissect the endogenous dopaminergic circuits have limited specificity, reversibility, resolution, or require genetic manipulation. Here, we introduce azodopa, a novel photoswitchable ligand that enables reversible spatiotemporal control of dopaminergic transmission. We demonstrate that azodopa activates D1-like receptors in vitro in a light-dependent manner. Moreover, it enables reversibly photocontrolling zebrafish motility on a timescale of seconds and allows separating the retinal component of dopaminergic neurotransmission. Azodopa increases the overall neural activity in the cortex of anesthetized mice and displays illumination-dependent activity in individual cells. Azodopa is the first photoswitchable dopamine agonist with demonstrated efficacy in wild-type animals and opens the way to remotely controlling dopaminergic neurotransmission for fundamental and therapeutic purposes." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "Understanding the activation of G protein-coupled receptors (GPCRs) is of paramount importance to the field of cardiovascular medicine due to the critical physiological roles of these receptors and their prominence as drug targets. Although many cardiovascular GPCRs have been extensively studied as model receptors for decades, new complexities in their regulation continue to emerge. As a result, there is an ongoing need to develop novel approaches to monitor and to modulate GPCR activation. In less than a decade, nanobodies, or recombinant single-domain antibody fragments from camelids, have become indispensable tools for interrogating GPCRs both in purified systems and in living cells. Nanobodies have gained traction rapidly due to their biochemical tractability and their ability to recognize defined states of native proteins. Here, we review how nanobodies have been adopted to elucidate the structure, pharmacology, and signaling of cardiovascular GPCRs, resolving long-standing mysteries and revealing unexpected mechanisms. We also discuss how advancing technologies to discover nanobodies with tailored specificities may expand the impact of these tools for both basic science and therapeutic applications." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "Adhesion G protein-coupled receptors (aGPCRs) are keys of many physiological events and attractive targets for various diseases. aGPCRs are also known to be capable of self-activation via an autoproteolysis process that removes the inhibitory GAIN domain on the extracellular side of receptor and releases a stalk peptide to bind and activate the transmembrane side of receptor. However, the detailed mechanism of aGPCR activation remains elusive. Here, we report the cryo-electron microscopy structures of GPR110 (ADGRF1), a member of aGPCR, in complex with Gq, Gs, Gi, G12 and G13. The structures reveal distinctive ligand engaging model and activation conformations of GPR110. The structures also unveil the rarely explored GPCR/G12 and GPCR/G13 engagements. A comparison of Gq, Gs, Gi, G12 and G13 engagements with GPR110 reveals details of G-protein engagement, including a dividing point at the far end of the alpha helix 5 (αH5) of Gα subunit that separates Gq/Gs engagements from Gi/G12/G13 engagements. This is also where Gq/Gs bind the receptor through both hydrophobic and polar interaction, while Gi/G12/G13 engage receptor mainly through hydrophobic interaction. We further provide physiological evidence of GPR110 activation via stalk peptide. Taken together, our study fills the missing information of GPCR/G-protein engagement and provides a framework for understanding aGPCR activation and GPR110 signaling." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "The canonical model for G protein-coupled receptors (GPCRs) activation assumes that stimulation of heterotrimeric G protein signaling upon ligand binding occurs solely at the cell surface and that duration of the stimulation is transient to prevent overstimulation. In this model, GPCR signaling is turned-off by receptor phosphorylation via GPCR kinases (GRKs) and subsequent recruitment of β-arrestins, resulting in receptor internalization into endosomes. Internalized receptors can then recycle back to the cell surface or be trafficked to lysosomes for degradation. However, over the last decade, this model has been extended by discovering that some internalized GPCRs continue to signal via G proteins from endosomes. This is the case for the parathyroid hormone (PTH) type 1 receptor (PTHR), which engages on sustained cAMP signaling from endosomes upon PTH stimulation. Accumulative evidence shows that the location of signaling has an impact on the physiological effects of GPCR signaling. This mini-review discusses recent insights into the mechanisms of PTHR endosomal signaling and its physiological impact." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "CXCR1 and CXCR2 chemokine receptors, mainly activated by interleukin 8 (IL-8 or CXCL8), are expressed in a variety of cells including, leukocytes, fibroblasts, endothelial cells, and smooth muscle cells. Numerous intracellular mediators are activated by these G protein-coupled receptors based on several factors, including the nature of the ligand, its concentration, and the binding sites with the receptor, levels of the receptor, cell type, and stimulatory environment. Much focus is currently being directed towards CXCR1/2 inhibitors, as these receptors primarily induce the chemotaxis of leukocytes, especially neutrophils, during inflammation, a key process in cardiovascular disease (CVD) progression. CXCR1/2 inhibitors show beneficial effects in various animal models of CVD. These effects include reducing the atherosclerotic plaque area, improving the serum lipid profile, attenuation of the damage following ischemia-reperfusion, the regulation of blood pressure, and the restriction of cardiac remodeling. Based on these encouraging results, testing CXCR1/2 inhibitors in clinical trials could be of a great importance to limit the inflammatory complications associated with CVDs." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 "G protein-coupled receptors (GPCRs) play critical roles in human physiology and are one of the prime targets for marketed drugs. While traditional drug discovery programs have focused on the development of ligands targeting the binding site of endogenous ligands (orthosteric site), allosteric modulators offer new avenues for the regulation of GPCR function with potential therapeutic benefits. Recent advances in the structure determination of GPCRs bound to different types of allosteric modulators have led to the identification of multiple allosteric sites and significantly enhanced our understanding of how allosteric ligands interact with receptors. These structural insights, together with the plethora of GPCR structures available today, will facilitate structure-based discovery and development of allosteric modulators as novel therapeutic candidates. In this review, we provide a systematic analysis of the currently available GPCR structures in complex with small-molecule allosteric ligands in terms of the location of allosteric pockets, receptor-ligand interactions, and the chemical features of the allosteric modulators. In addition, we summarize current strategies for the identification of allosteric sites as well as ligand-based and structure-based drug discovery and design." Read more at the source #DrGPCR #GPCR #IndustryNews

October 2022 Structural perspectives on the mechanism of signal activation, ligand selectivity and allosteric modulation in angiotensin receptors: IUPHAR Review 34 "Functional advances have guided our knowledge of physiological and fatal pathological mechanisms of the hormone angiotensin II (AngII) and its antagonists. Such studies revealed that tissue response to a given dose of the hormone or its antagonist depends on receptors that engage the ligand. Thus, we need to know much more about the structures of receptor-ligand complexes at high resolution. Recently, X-ray structures of both AngII receptors (AT1 and AT2 receptors) bound to peptide and non-peptide ligands have been elucidated, providing new opportunities to examine the dynamic fluxes in the 3D architecture of the receptors, as the basis of ligand selectivity, efficacy, and regulation of the molecular functions of the receptors. Constituent structural motifs cooperatively transform ligand selectivity into specific functions, thus conceptualizing the primacy of the 3D structure over individual motifs of receptors. This review covers the new data elucidating the structural dynamics of AngII receptors and how structural knowledge can be transformative in understanding the mechanisms underlying the physiology of AngII." Read more at the source #DrGPCR #GPCR #IndustryNews