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McNeill SM, Zhao P. The roles of RGS proteins in cardiometabolic disease. Br J Pharmacol 2024; 181:2319-2337. [PMID: 36964984 DOI: 10.1111/bph.16076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/12/2023] [Accepted: 03/20/2023] [Indexed: 03/27/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are the most prominent receptors on the surface of the cell and play a central role in the regulation of cardiac and metabolic functions. GPCRs transmit extracellular stimuli to the interior of the cells by activating one or more heterotrimeric G proteins. The duration and intensity of G protein-mediated signalling are tightly controlled by a large array of intracellular mediators, including the regulator of G protein signalling (RGS) proteins. RGS proteins selectively promote the GTPase activity of a subset of Gα subunits, thus serving as negative regulators in a pathway-dependent manner. In the current review, we summarise the involvement of RGS proteins in cardiometabolic function with a focus on their tissue distribution, mechanisms of action and dysregulation under various disease conditions. We also discuss the potential therapeutic applications for targeting RGS proteins in treating cardiometabolic conditions and current progress in developing RGS modulators. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Samantha M McNeill
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Peishen Zhao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins (CCeMMP), Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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Huang J, Xie Y, Chen B, Xia Y, Jiang Y, Sun Z, Liu Y. GPR146 regulates pulmonary vascular remodeling by promoting pulmonary artery smooth muscle cell proliferation through 5-lipoxygenase. Eur J Pharmacol 2023; 961:176123. [PMID: 37926274 DOI: 10.1016/j.ejphar.2023.176123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/07/2023]
Abstract
The pathological feature of hypoxic pulmonary hypertension (PH) is pulmonary vascular remodeling (PVR), primarily attributed to the hyperproliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs). Existing PH-targeted drugs have difficulties in reversing PVR. Therefore, it is vital to discover a new regulatory mechanism for PVR and develop new targeted drugs. G protein-coupled receptor 146 (GPR146) is believed to participate in this process. This study aimed to investigate the role of GPR146 in PASMCs during PH. We investigated the role of GPR146 in PVR and its underlying mechanism using hypoxic PASMCs and mouse model (Sugen 5416 (20 mg/kg)/hypoxia). In our recent study, we have observed a significant increase in the expression of GPR146 protein in animal models of PH as well as in patients diagnosed with pulmonary arterial hypertension (PAH). Through immunohistochemistry, we found that GPR146 was mainly localized in the smooth muscle and endothelial layers of the pulmonary vasculature. GPR146 deficiency induction exhibited protective effects against hypoxia-induced elevation of right ventricular systolic blood pressure (RVSP), right ventricular hypertrophy, and pulmonary vascular remodeling in mice. In particular, the deletion of GPR146 attenuated the hypoxia-triggered proliferation of PASMCs. Furthermore, 5-lipoxygenase (5-LO) was related to PH development. Hypoxia and overexpression of GPR146 increased 5-LO expression, which was reversed through GPR146 knockdown or siRNA intervention. Our study discovered that GPR146 exhibited high expression in the pulmonary vessels of pulmonary hypertension. Subsequent research revealed that GPR146 played a crucial role in the development of hypoxic PH by promoting lipid peroxidation and 5-LO expression. In conclusion, GPR146 may regulate pulmonary vascular remodeling by promoting PASMCs proliferation through 5-LO, which presents a feasible target for PH prevention and treatment.
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Affiliation(s)
- Jie Huang
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Yongpeng Xie
- Department of Emergency and Critical Care Medicine, Lianyungang Clinical College of Nanjing Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Bing Chen
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Yu Xia
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Yanjiao Jiang
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Zengxian Sun
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China; Department of Emergency and Critical Care Medicine, Lianyungang Clinical College of Nanjing Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China
| | - Yun Liu
- Department of Pharmacy, The Affiliated Lianyungang Hospital of Xuzhou Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China; Department of Pharmacy, Lianyungang Clinical College of Nanjing Medical University/The First People's Hospital of Lianyungang, Lianyungang, 222061, China.
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Areloegbe SE, Olaniyi KS. Acetate mitigates cardiac mitochondrial dysfunction in experimental model of polycystic ovarian syndrome by modulating GPCR41/43 and PROKR1. Biochem Biophys Res Commun 2023; 681:62-72. [PMID: 37757668 DOI: 10.1016/j.bbrc.2023.09.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/03/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023]
Abstract
The role of short chain fatty acid, acetate in cardiac mitochondrial dysfunction especially in PCOS individuals is unknown. Therefore, the present study investigated the modulatory role of GPCRs (41 and 43) by acetate on cardiac mitochondrial status in PCOS rat model. Eight-week-old female Wistar rats were randomly allotted into four groups (n = 5). Polycystic ovarian syndrome was induced by administering letrozole (1 mg/kg p.o.) once daily for 21 days, thereafter the animals were treated with 200 mg/kg (oral gavage) of acetate for six weeks. Letrozole-induced PCOS rats showed elevated circulating testosterone and anti-mullerian hormone, with multiple ovarian cysts. In addition, these rats also manifested insulin resistance, hyperinsulinemia, and increased plasma triglyceride (TG), TG/HDLc and decreased HDLc, as well as elevated level of cardiac TG, glycogen, glycogen synthase, and plasma/cardiac NF-kB, TNF-α, and SDF-1. Cardiac MDA and caspase-6 increased, while plasma/cardiac NrF2 decreased in PCOS animals. A decrease in mitochondrial ATP synthase, ATP/AMP ratio, CPT2 and SDH, and increased HDAC2 were observed in PCOS rats with decreased level of GPCR 41 and 43 when compared with control. Immunohistochemical evaluation of cardiac tissue also showed decrease expression of PROKR1 in PCOS rats compared with control rats. However, treatment with acetate reversed these systemic, cardiac and mitochondrial anomalies. The present results suggest the therapeutic benefit of acetate, an HDAC2i against cardiac mitochondrial dysfunction in PCOS rat model, by attenuating cardiac inflammation, oxidative stress and apoptosis and these effects are accompanied by modulation of GPCR41 and 43 as well as increased expression of PROKR1.
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Affiliation(s)
- Stephanie E Areloegbe
- Cardio/Endo-metabolic and Microbiome Research Unit, Department of Physiology, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, 360101, Nigeria
| | - Kehinde S Olaniyi
- Cardio/Endo-metabolic and Microbiome Research Unit, Department of Physiology, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, 360101, Nigeria.
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Lutz JA, Sulima A, Gutman ES, Bow EW, Luo D, Kaska S, Prisinzano TE, Paronis CA, Bergman J, Imler GH, Kerr AT, Jacobson AE, Rice KC. Discovery of a Potent Highly Biased MOR Partial Agonist among Diastereomeric C9-Hydroxyalkyl-5-phenylmorphans. Molecules 2023; 28:4795. [PMID: 37375350 DOI: 10.3390/molecules28124795] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
All possible diastereomeric C9-hydroxymethyl-, hydroxyethyl-, and hydroxypropyl-substituted 5-phenylmorphans were synthesized to explore the three-dimensional space around the C9 substituent in our search for potent MOR partial agonists. These compounds were designed to lessen the lipophilicity observed with their C9-alkenyl substituted relatives. Many of the 12 diastereomers that were obtained were found to have nanomolar or subnanomolar potency in the forskolin-induced cAMP accumulation assay. Almost all these potent compounds were fully efficacious, and three of those chosen for in vivo evaluation, 15, 21, and 36, were all extremely G-protein biased; none of the three compounds recruited beta-arrestin2. Only one of the 12 diastereomers, 21 (3-((1S,5R,9R)-9-(2-hydroxyethyl)-2-phenethyl-2-azabicyclo[3.3.1]nonan-5-yl)phenol), was a MOR partial agonist with good, but not full, efficacy (Emax = 85%) and subnanomolar potency (EC50 = 0.91 nM) in the cAMP assay. It did not have any KOR agonist activity. This compound was unlike morphine in that it had a limited ventilatory effect in vivo. The activity of 21 could be related to one or more of three well-known theories that attempt to predict a dissociation of the desired analgesia from the undesirable opioid-like side-effects associated with clinically used opioids. In accordance with the theories, 21 was a potent MOR partial agonist, it was highly G-protein biased and did not attract beta-arrestin2, and it was found to have both MOR and DOR agonist activity. All the other diastereomers that were synthesized were either much less potent than 21 or had either too little or too much efficacy for our purposes. It was also noted that a C9-methoxymethyl compound with 1R,5S,9R stereochemistry (41) was more potent than the comparable C9-hydroxymethyl compound 11 (EC50 = 0.65 nM for 41 vs. 2.05 nM for 11). Both 41 and 11 were fully efficacious.
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Affiliation(s)
- Joshua A Lutz
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
| | - Agnieszka Sulima
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
| | - Eugene S Gutman
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
| | - Eric W Bow
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
| | - Dan Luo
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA
| | - Sophia Kaska
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA
| | - Thomas E Prisinzano
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, KY 40536, USA
| | - Carol A Paronis
- McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA
| | - Jack Bergman
- McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA
| | - Gregory H Imler
- Center for Biomolecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375-0001, USA
| | - Andrew T Kerr
- Center for Biomolecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375-0001, USA
| | - Arthur E Jacobson
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
| | - Kenner C Rice
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, Intramural Research Program, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Department of Health and Human Services, 9800 Medical Center Drive, Bethesda, MD 20892-3373, USA
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Duan S, Jiang X, Li J, Fu M, Li Z, Cheng Y, Zhuang Y, Yang M, Xiao W, Ping H, Xie Y, Xie X, Zhang X. The RXFP2-PLC/PKC signaling pathway mediates INSL3-induced regulation of the proliferation, migration and apoptosis of mouse gubernacular cells. Cell Mol Biol Lett 2023; 28:16. [PMID: 36849880 PMCID: PMC9972740 DOI: 10.1186/s11658-023-00433-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/20/2023] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Testicular hypoplasia can affect the sexual and reproductive ability in adulthood, and even increase the risk of cancer. Abnormal development of the gubernaculum is one of the important factors of testicular hypoplasia. Therefore, a study of the structure and function of the gubernaculum is an important but neglected new breakthrough point for investigating the normal/abnormal development of the testis. Previous findings showed that Insulin like factor 3 (INSL3) is a key factor regulating the growth of gubernaculum, however, the mechanism by which INSL3 acts on the gubernaculum remains unknown. Therefore, we probed the mechanism associated with INSL3-induced the proliferation, migration, and apoptosis of gubernacular cells in mice. METHODS A culture cell model of neonatal mice gubernaculum is established by INSL3 intervention. We blocked PLC/PKC signaling pathway with U73122 pretreat to investigate the role of the PLC/PKC signaling pathway. The changes of cell proliferation, migration, and apoptosis were detected by molecular biological methods. In addition, the levels of PCNA and F-action were detected by immunofluorescence and western blotting. RESULTS We found that INSL3 can promote the proliferation and migration of gubernacular cells and inhibit their apoptosis, meanwhile, INSL3 significantly up-regulated PLC/PKC protein phosphorylation. However, treatment with the PLC/PKC signaling pathway inhibitor U73122 significantly inhibited these effects of INSL3. Besides, we found that INSL3 could up-regulate the protein expression level of PCNA and F-actin, while the PCNA and F-actin expression was significantly weakened after U73122 pretreatment. CONCLUSIONS This research revealed that INSL3 binding to RXFP2 may up-regulate the expression levels of PCNA and F-actin by activating the PLC/PKC signaling pathway to promote the proliferation and migration of gubernacular cells. It suggests that the RXFP2-PLC/PKC axis may serve as a novel molecular mechanism by which INSL3 regulates growth of the gubernaculum.
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Affiliation(s)
- Shouxing Duan
- Department of Pediatric Surgery, Huazhong University of Science and Technology Union Shenzhen Hospital (Nanshan Hospital), No. 89 Taoyuan Road, Shenzhen, 518052, Guangdong, China
- Department of Pediatric Surgery, The First Affiliated Hospital of Shantou University Medical College, No. 57 Changping Road, Shantou, 515041, Guangdong, China
| | - Xuewu Jiang
- Department of Pediatric Surgery, Pingshan District Maternal and Child Healthcare Hospital of Shenzhen, Pingshan General Hospital of Southern Medical University, No. 6 Longxingnan Road, Shenzhen, 518118, Guangdong, China
| | - Jianhong Li
- Department of Pediatric Surgery, The Second Affiliated Hospital of Shantou University Medical College, No. 69 Dongxiabei Road, Shantou, 515041, Guangdong, China
| | - Maxian Fu
- Department of Pediatric Surgery, Huazhong University of Science and Technology Union Shenzhen Hospital (Nanshan Hospital), No. 89 Taoyuan Road, Shenzhen, 518052, Guangdong, China
| | - Zhuo Li
- Department of Pediatric Surgery, Huazhong University of Science and Technology Union Shenzhen Hospital (Nanshan Hospital), No. 89 Taoyuan Road, Shenzhen, 518052, Guangdong, China
| | - Yiyi Cheng
- Department of Pediatric Surgery, The First Affiliated Hospital of Shantou University Medical College, No. 57 Changping Road, Shantou, 515041, Guangdong, China
| | - Yangmu Zhuang
- Department of Pediatric Surgery, The First Affiliated Hospital of Shantou University Medical College, No. 57 Changping Road, Shantou, 515041, Guangdong, China
| | - Ming Yang
- Department of Pediatric Surgery, The First Affiliated Hospital of Shantou University Medical College, No. 57 Changping Road, Shantou, 515041, Guangdong, China
| | - Wenfeng Xiao
- Department of Pediatric Surgery, The Second Affiliated Hospital of Shantou University Medical College, No. 69 Dongxiabei Road, Shantou, 515041, Guangdong, China
| | - Hongyan Ping
- Department of Pediatric Surgery, Pingshan District Maternal and Child Healthcare Hospital of Shenzhen, Pingshan General Hospital of Southern Medical University, No. 6 Longxingnan Road, Shenzhen, 518118, Guangdong, China
| | - Yao Xie
- Department of Radiology, Cancer Hospital of Shantou University Medical College, No. 7 Raoping Road, Shantou, 515041, Guangdong, China.
| | - Xiaojun Xie
- Department of General Surgery, The First Affiliated Hospital of Shantou University Medical College, No. 57 Changping Road, Shantou, 515041, Guangdong, China.
| | - Xuan Zhang
- Department of Pediatric Surgery, Pingshan District Maternal and Child Healthcare Hospital of Shenzhen, Pingshan General Hospital of Southern Medical University, No. 6 Longxingnan Road, Shenzhen, 518118, Guangdong, China.
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Loken LC, Corsi SR, Alvarez DA, Ankley GT, Baldwin AK, Blackwell BR, De Cicco LA, Nott MA, Oliver SK, Villeneuve DL. Prioritizing Pesticides of Potential Concern and Identifying Potential Mixture Effects in Great Lakes Tributaries Using Passive Samplers. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:340-366. [PMID: 36165576 PMCID: PMC10107608 DOI: 10.1002/etc.5491] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/06/2022] [Accepted: 09/22/2022] [Indexed: 05/24/2023]
Abstract
To help meet the objectives of the Great Lakes Restoration Initiative with regard to increasing knowledge about toxic substances, 223 pesticides and pesticide transformation products were monitored in 15 Great Lakes tributaries using polar organic chemical integrative samplers. A screening-level assessment of their potential for biological effects was conducted by computing toxicity quotients (TQs) for chemicals with available US Environmental Protection Agency (USEPA) Aquatic Life Benchmark values. In addition, exposure activity ratios (EAR) were calculated using information from the USEPA ToxCast database. Between 16 and 81 chemicals were detected per site, with 97 unique compounds detected overall, for which 64 could be assessed using TQs or EARs. Ten chemicals exceeded TQ or EAR levels of concern at two or more sites. Chemicals exceeding thresholds included seven herbicides (2,4-dichlorophenoxyacetic acid, diuron, metolachlor, acetochlor, atrazine, simazine, and sulfentrazone), a transformation product (deisopropylatrazine), and two insecticides (fipronil and imidacloprid). Watersheds draining agricultural and urban areas had more detections and higher concentrations of pesticides compared with other land uses. Chemical mixtures analysis for ToxCast assays associated with common modes of action defined by gene targets and adverse outcome pathways (AOP) indicated potential activity on biological pathways related to a range of cellular processes, including xenobiotic metabolism, extracellular signaling, endocrine function, and protection against oxidative stress. Use of gene ontology databases and the AOP knowledgebase within the R-package ToxMixtures highlighted the utility of ToxCast data for identifying and evaluating potential biological effects and adverse outcomes of chemicals and mixtures. Results have provided a list of high-priority chemicals for future monitoring and potential biological effects warranting further evaluation in laboratory and field environments. Environ Toxicol Chem 2023;42:340-366. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Luke C. Loken
- US Geological SurveyUpper Midwest Water Science CenterMadisonWisconsinUSA
| | - Steven R. Corsi
- US Geological SurveyUpper Midwest Water Science CenterMadisonWisconsinUSA
| | - David A. Alvarez
- US Geological SurveyColumbia Environmental Research CenterColombiaMissouriUSA
| | - Gerald T. Ankley
- US Environmental Protection Agency, Center for Computational Toxicology and ExposureGreat Lakes Toxicology and Ecology DivisionDuluthMinnesotaUSA
| | | | - Brett R. Blackwell
- US Environmental Protection Agency, Center for Computational Toxicology and ExposureGreat Lakes Toxicology and Ecology DivisionDuluthMinnesotaUSA
| | - Laura A. De Cicco
- US Geological SurveyUpper Midwest Water Science CenterMadisonWisconsinUSA
| | - Michele A. Nott
- US Geological SurveyUpper Midwest Water Science CenterMadisonWisconsinUSA
| | - Samantha K. Oliver
- US Geological SurveyUpper Midwest Water Science CenterMadisonWisconsinUSA
| | - Daniel L. Villeneuve
- US Environmental Protection Agency, Center for Computational Toxicology and ExposureGreat Lakes Toxicology and Ecology DivisionDuluthMinnesotaUSA
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Su M, Paknejad N, Zhu L, Wang J, Do HN, Miao Y, Liu W, Hite RK, Huang XY. Structures of β 1-adrenergic receptor in complex with Gs and ligands of different efficacies. Nat Commun 2022; 13:4095. [PMID: 35835792 PMCID: PMC9283524 DOI: 10.1038/s41467-022-31823-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) receive signals from ligands with different efficacies, and transduce to heterotrimeric G-proteins to generate different degrees of physiological responses. Previous studies revealed how ligands with different efficacies activate GPCRs. Here, we investigate how a GPCR activates G-proteins upon binding ligands with different efficacies. We report the cryo-EM structures of β1-adrenergic receptor (β1-AR) in complex with Gs (GαsGβ1Gγ2) and a partial agonist or a very weak partial agonist, and compare them to the β1-AR-Gs structure in complex with a full agonist. Analyses reveal similar overall complex architecture, with local conformational differences. Cellular functional studies with mutations of β1-AR residues show effects on the cellular signaling from β1-AR to the cAMP response initiated by the three different ligands, with residue-specific functional differences. Biochemical investigations uncover that the intermediate state complex comprising β1-AR and nucleotide-free Gs is more stable when binding a full agonist than a partial agonist. Molecular dynamics simulations support the local conformational flexibilities and different stabilities among the three complexes. These data provide insights into the ligand efficacy in the activation of GPCRs and G-proteins.
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Affiliation(s)
- Minfei Su
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY, 10065, USA
| | - Navid Paknejad
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Lan Zhu
- Cancer Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Jinan Wang
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA
| | - Hung Nguyen Do
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA
| | - Wei Liu
- Cancer Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
| | - Xin-Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY, 10065, USA.
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8
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Durník R, Šindlerová L, Babica P, Jurček O. Bile Acids Transporters of Enterohepatic Circulation for Targeted Drug Delivery. Molecules 2022; 27:molecules27092961. [PMID: 35566302 PMCID: PMC9103499 DOI: 10.3390/molecules27092961] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/24/2022] [Accepted: 05/02/2022] [Indexed: 12/29/2022] Open
Abstract
Bile acids (BAs) are important steroidal molecules with a rapidly growing span of applications across a variety of fields such as supramolecular chemistry, pharmacy, and biomedicine. This work provides a systematic review on their transport processes within the enterohepatic circulation and related processes. The focus is laid on the description of specific or less-specific BA transport proteins and their localization. Initially, the reader is provided with essential information about BAs′ properties, their systemic flow, metabolism, and functions. Later, the transport processes are described in detail and schematically illustrated, moving step by step from the liver via bile ducts to the gallbladder, small intestine, and colon; this description is accompanied by descriptions of major proteins known to be involved in BA transport. Spillage of BAs into systemic circulation and urine excretion are also discussed. Finally, the review also points out some of the less-studied areas of the enterohepatic circulation, which can be crucial for the development of BA-related drugs, prodrugs, and drug carrier systems.
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Affiliation(s)
- Robin Durník
- Department of Biochemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic;
| | - Lenka Šindlerová
- Department of Biophysics of Immune System, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech Republic;
| | - Pavel Babica
- RECETOX, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic;
| | - Ondřej Jurček
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
- CEITEC—Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
- Department of Natural Drugs, Faculty of Pharmacy, Masaryk University, Palackého 1946/1, 61200 Brno, Czech Republic
- Correspondence:
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9
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Hoare SRJ, Tewson PH, Sachdev S, Connor M, Hughes TE, Quinn AM. Quantifying the Kinetics of Signaling and Arrestin Recruitment by Nervous System G-Protein Coupled Receptors. Front Cell Neurosci 2022; 15:814547. [PMID: 35110998 PMCID: PMC8801586 DOI: 10.3389/fncel.2021.814547] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
Neurons integrate inputs over different time and space scales. Fast excitatory synapses at boutons (ms and μm), and slow modulation over entire dendritic arbors (seconds and mm) are all ultimately combined to produce behavior. Understanding the timing of signaling events mediated by G-protein-coupled receptors is necessary to elucidate the mechanism of action of therapeutics targeting the nervous system. Measuring signaling kinetics in live cells has been transformed by the adoption of fluorescent biosensors and dyes that convert biological signals into optical signals that are conveniently recorded by microscopic imaging or by fluorescence plate readers. Quantifying the timing of signaling has now become routine with the application of equations in familiar curve fitting software to estimate the rates of signaling from the waveform. Here we describe examples of the application of these methods, including (1) Kinetic analysis of opioid signaling dynamics and partial agonism measured using cAMP and arrestin biosensors; (2) Quantifying the signaling activity of illicit synthetic cannabinoid receptor agonists measured using a fluorescent membrane potential dye; (3) Demonstration of multiplicity of arrestin functions from analysis of biosensor waveforms and quantification of the rates of these processes. These examples show how temporal analysis provides additional dimensions to enhance the understanding of GPCR signaling and therapeutic mechanisms in the nervous system.
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Affiliation(s)
- Sam R. J. Hoare
- Pharmechanics LLC, Owego, NY, United States
- *Correspondence: Sam R. J. Hoare
| | | | - Shivani Sachdev
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mark Connor
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
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10
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Seibel-Ehlert U, Plank N, Inoue A, Bernhardt G, Strasser A. Label-Free Investigations on the G Protein Dependent Signaling Pathways of Histamine Receptors. Int J Mol Sci 2021; 22:9739. [PMID: 34575903 PMCID: PMC8467282 DOI: 10.3390/ijms22189739] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 01/14/2023] Open
Abstract
G protein activation represents an early key event in the complex GPCR signal transduction process and is usually studied by label-dependent methods targeting specific molecular events. However, the constrained environment of such "invasive" techniques could interfere with biological processes. Although histamine receptors (HRs) represent (evolving) drug targets, their signal transduction is not fully understood. To address this issue, we established a non-invasive dynamic mass redistribution (DMR) assay for the human H1-4Rs expressed in HEK cells, showing excellent signal-to-background ratios above 100 for histamine (HIS) and higher than 24 for inverse agonists with pEC50 values consistent with literature. Taking advantage of the integrative nature of the DMR assay, the involvement of endogenous Gαq/11, Gαs, Gα12/13 and Gβγ proteins was explored, pursuing a two-pronged approach, namely that of classical pharmacology (G protein modulators) and that of molecular biology (Gα knock-out HEK cells). We showed that signal transduction of hH1-4Rs occurred mainly, but not exclusively, via their canonical Gα proteins. For example, in addition to Gαi/o, the Gαq/11 protein was proven to contribute to the DMR response of hH3,4Rs. Moreover, the Gα12/13 was identified to be involved in the hH2R mediated signaling pathway. These results are considered as a basis for future investigations on the (patho)physiological role and the pharmacological potential of H1-4Rs.
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Affiliation(s)
- Ulla Seibel-Ehlert
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany; (N.P.); (G.B.)
| | - Nicole Plank
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany; (N.P.); (G.B.)
| | - Asuka Inoue
- Department of Pharmacological Sciences, Tohoku University, Sendai 980-8578, Japan;
| | - Guenther Bernhardt
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany; (N.P.); (G.B.)
| | - Andrea Strasser
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, 93040 Regensburg, Germany; (N.P.); (G.B.)
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11
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Lu S, He X, Yang Z, Chai Z, Zhou S, Wang J, Rehman AU, Ni D, Pu J, Sun J, Zhang J. Activation pathway of a G protein-coupled receptor uncovers conformational intermediates as targets for allosteric drug design. Nat Commun 2021; 12:4721. [PMID: 34354057 PMCID: PMC8342441 DOI: 10.1038/s41467-021-25020-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 07/17/2021] [Indexed: 02/07/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are the most common proteins targeted by approved drugs. A complete mechanistic elucidation of large-scale conformational transitions underlying the activation mechanisms of GPCRs is of critical importance for therapeutic drug development. Here, we apply a combined computational and experimental framework integrating extensive molecular dynamics simulations, Markov state models, site-directed mutagenesis, and conformational biosensors to investigate the conformational landscape of the angiotensin II (AngII) type 1 receptor (AT1 receptor) - a prototypical class A GPCR-activation. Our findings suggest a synergistic transition mechanism for AT1 receptor activation. A key intermediate state is identified in the activation pathway, which possesses a cryptic binding site within the intracellular region of the receptor. Mutation of this cryptic site prevents activation of the downstream G protein signaling and β-arrestin-mediated pathways by the endogenous AngII octapeptide agonist, suggesting an allosteric regulatory mechanism. Together, these findings provide a deeper understanding of AT1 receptor activation at an atomic level and suggest avenues for the design of allosteric AT1 receptor modulators with a broad range of applications in GPCR biology, biophysics, and medicinal chemistry.
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Affiliation(s)
- Shaoyong Lu
- College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, China.
- State Key Laboratory of Oncogenes and Related Genes, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, China.
| | - Xinheng He
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Material Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhao Yang
- Department of Biochemistry and Molecular Biology, Key Laboratory Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Zongtao Chai
- Department of Hepatic Surgery VI, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Shuhua Zhou
- Department of Biochemistry and Molecular Biology, Key Laboratory Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Junyan Wang
- Department of Biochemistry and Molecular Biology, Key Laboratory Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Ashfaq Ur Rehman
- State Key Laboratory of Oncogenes and Related Genes, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Duan Ni
- State Key Laboratory of Oncogenes and Related Genes, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Jun Pu
- Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Jinpeng Sun
- Department of Biochemistry and Molecular Biology, Key Laboratory Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong, China.
| | - Jian Zhang
- College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, China.
- State Key Laboratory of Oncogenes and Related Genes, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, China.
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China.
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12
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Mobbs JI, Belousoff MJ, Harikumar KG, Piper SJ, Xu X, Furness SGB, Venugopal H, Christopoulos A, Danev R, Wootten D, Thal DM, Miller LJ, Sexton PM. Structures of the human cholecystokinin 1 (CCK1) receptor bound to Gs and Gq mimetic proteins provide insight into mechanisms of G protein selectivity. PLoS Biol 2021; 19:e3001295. [PMID: 34086670 PMCID: PMC8208569 DOI: 10.1371/journal.pbio.3001295] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/16/2021] [Accepted: 05/19/2021] [Indexed: 01/08/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are critical regulators of cellular function acting via heterotrimeric G proteins as their primary transducers with individual GPCRs capable of pleiotropic coupling to multiple G proteins. Structural features governing G protein selectivity and promiscuity are currently unclear. Here, we used cryo-electron microscopy (cryo-EM) to determine structures of the cholecystokinin (CCK) type 1 receptor (CCK1R) bound to the CCK peptide agonist, CCK-8 and 2 distinct transducer proteins, its primary transducer Gq, and the more weakly coupled Gs. As seen with other Gq/11-GPCR complexes, the Gq-α5 helix (αH5) bound to a relatively narrow pocket in the CCK1R core. Surprisingly, the backbone of the CCK1R and volume of the G protein binding pocket were essentially equivalent when Gs was bound, with the Gs αH5 displaying a conformation that arises from "unwinding" of the far carboxyl-terminal residues, compared to canonically Gs coupled receptors. Thus, integrated changes in the conformations of both the receptor and G protein are likely to play critical roles in the promiscuous coupling of individual GPCRs.
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MESH Headings
- Cholecystokinin/metabolism
- Cholesterol/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/chemistry
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/ultrastructure
- GTP-Binding Protein alpha Subunits, Gs/chemistry
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- GTP-Binding Protein alpha Subunits, Gs/ultrastructure
- HEK293 Cells
- Humans
- Models, Molecular
- Protein Binding
- Receptors, Cholecystokinin/chemistry
- Receptors, Cholecystokinin/metabolism
- Receptors, Cholecystokinin/ultrastructure
- Signal Transduction
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Affiliation(s)
- Jesse I. Mobbs
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Matthew J. Belousoff
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Kaleeckal G. Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Sarah J. Piper
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Xiaomeng Xu
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Sebastian G. B. Furness
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Radostin Danev
- Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Denise Wootten
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - David M. Thal
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Laurence J. Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Patrick M. Sexton
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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13
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Functional approaches to the study of G-protein-coupled receptors in postmortem brain tissue: [ 35S]GTPγS binding assays combined with immunoprecipitation. Pharmacol Rep 2021; 73:1079-1095. [PMID: 33876404 DOI: 10.1007/s43440-021-00253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 10/21/2022]
Abstract
G-protein-coupled receptors (GPCRs) have an enormous biochemical importance as they bind to diverse extracellular ligands and regulate a variety of physiological and pathological responses. G-protein activation measures the functional consequence of receptor occupancy at one of the earliest receptor-mediated events. Receptor coupling to G-proteins promotes the GDP/GTP exchange on Gα subunits. Thus, modulation of the binding of the poorly hydrolysable GTP analog [35S]GTPγS to the Gα-protein subunit can be used as a functional approach to quantify GPCR interaction with agonist, antagonist or inverse agonist drugs. In order to determine receptor-mediated selective activation of the different Gα-proteins, [35S]GTPγS binding assays combined with immunodetection by specific antibodies have been developed and applied to physiological and pathological brain conditions. Currently, immunoprecipitation with magnetic beads and scintillation proximity assays are the most habitual techniques for this purpose. The present review summarizes the different procedures, advantages and limitations of the [35S]GTPγS binding assays combined with selective Gα-protein sequestration methods. Experience of functional coupling of several GPCRs to different Gα-proteins and recommendations for optimal performance in brain membranes are described. One of the biggest opportunities opened by these techniques is that they enable evaluation of biased agonism in the native tissue, which results in high interest in drug discovery. The available results derived from application of these functional methodologies to study GPCR dysfunctions in neuro-psychiatric disorders are also described. In conclusion, [35S]GTPγS binding combined with antibody-mediated immunodetection represents an useful method to separately evaluate the functional activity of drugs acting on GPCRs over each Gα-protein subtype.
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14
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Abstract
The endocannabinoid system (ECS) is a highly versatile signaling system within the nervous system. Despite its widespread localization, its functions within the context of distinct neural processes are very well discernable and specific. This is remarkable, and the question remains as to how such specificity is achieved. One key player in the ECS is the cannabinoid type 1 receptor (CB1), a G protein-coupled receptor characterized by the complexity of its cell-specific expression, cellular and subcellular localization, and its adaptable regulation of intracellular signaling cascades. CB1 receptors are involved in different synaptic and cellular plasticity processes and in the brain's bioenergetics in a context-specific manner. CB2 receptors are also important in several processes in neurons, glial cells, and immune cells of the brain. As polymorphisms in ECS components, as well as external impacts such as stress and metabolic challenges, can both lead to dysregulated ECS activity and subsequently to possible neuropsychiatric disorders, pharmacological intervention targeting the ECS is a promising therapeutic approach. Understanding the neurobiology of cannabinoid receptor signaling in depth will aid optimal design of therapeutic interventions, minimizing unwanted side effects.
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Affiliation(s)
- Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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15
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Hoare SRJ, Tewson PH, Quinn AM, Hughes TE, Bridge LJ. Analyzing kinetic signaling data for G-protein-coupled receptors. Sci Rep 2020; 10:12263. [PMID: 32704081 PMCID: PMC7378232 DOI: 10.1038/s41598-020-67844-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023] Open
Abstract
In classical pharmacology, bioassay data are fit to general equations (e.g. the dose response equation) to determine empirical drug parameters (e.g. EC50 and Emax), which are then used to calculate chemical parameters such as affinity and efficacy. Here we used a similar approach for kinetic, time course signaling data, to allow empirical and chemical definition of signaling by G-protein-coupled receptors in kinetic terms. Experimental data are analyzed using general time course equations (model-free approach) and mechanistic model equations (mechanistic approach) in the commonly-used curve-fitting program, GraphPad Prism. A literature survey indicated signaling time course data usually conform to one of four curve shapes: the straight line, association exponential curve, rise-and-fall to zero curve, and rise-and-fall to steady-state curve. In the model-free approach, the initial rate of signaling is quantified and this is done by curve-fitting to the whole time course, avoiding the need to select the linear part of the curve. It is shown that the four shapes are consistent with a mechanistic model of signaling, based on enzyme kinetics, with the shape defined by the regulation of signaling mechanisms (e.g. receptor desensitization, signal degradation). Signaling efficacy is the initial rate of signaling by agonist-occupied receptor (kτ), simply the rate of signal generation before it becomes affected by regulation mechanisms, measurable using the model-free analysis. Regulation of signaling parameters such as the receptor desensitization rate constant can be estimated if the mechanism is known. This study extends the empirical and mechanistic approach used in classical pharmacology to kinetic signaling data, facilitating optimization of new therapeutics in kinetic terms.
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Affiliation(s)
- Sam R J Hoare
- Pharmechanics, LLC, 14 Sunnyside Drive South, Owego, NY, 13827, USA.
| | - Paul H Tewson
- Montana Molecular, 366 Gallatin Park Dr. Suite A, Bozeman, MT, 59715, USA
| | - Anne Marie Quinn
- Montana Molecular, 366 Gallatin Park Dr. Suite A, Bozeman, MT, 59715, USA
| | - Thomas E Hughes
- Montana Molecular, 366 Gallatin Park Dr. Suite A, Bozeman, MT, 59715, USA
| | - Lloyd J Bridge
- Department of Engineering Design and Mathematics, University of the West of England, Frenchay Campus, Bristol, BS16 1QY, UK
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16
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Stephens BS, Ngo T, Kufareva I, Handel TM. Functional anatomy of the full-length CXCR4-CXCL12 complex systematically dissected by quantitative model-guided mutagenesis. Sci Signal 2020; 13:eaay5024. [PMID: 32665413 PMCID: PMC7437921 DOI: 10.1126/scisignal.aay5024] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Because of their prominent roles in development, cancer, and HIV, the chemokine receptor CXCR4 and its ligand CXCL12 have been the subject of numerous structural and functional studies, but the determinants of ligand binding, selectivity, and signaling are still poorly understood. Here, building on our latest structural model, we used a systematic mutagenesis strategy to dissect the functional anatomy of the CXCR4-CXCL12 complex. Key charge swap mutagenesis experiments provided evidence for pairwise interactions between oppositely charged residues in the receptor and chemokine, confirming the accuracy of the predicted orientation of the chemokine relative to the receptor and providing insight into ligand selectivity. Progressive deletion of N-terminal residues revealed an unexpected contribution of the receptor N terminus to chemokine signaling. This finding challenges a longstanding "two-site" hypothesis about the essential features of the receptor-chemokine interaction in which the N terminus contributes only to binding affinity. Our results suggest that although the interaction of the chemokine N terminus with the receptor-binding pocket is the key driver of signaling, the signaling amplitude depends on the extent to which the receptor N terminus binds the chemokine. Together with systematic characterization of other epitopes, these data enable us to propose an experimentally consistent structural model for how CXCL12 binds CXCR4 and initiates signal transmission through the receptor transmembrane domain.
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Affiliation(s)
- Bryan S Stephens
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA.
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA.
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17
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Abstract
Primary aldosteronism (PA) is the most common form of endocrine hypertension. Agonistic autoantibodies against the angiotensin II type 1 receptor (AT1R-Abs) have been described in transplantation medicine and women with pre-eclampsia and more recently in patients with PA. Any functional role of AT1R-Abs in either of the two main subtypes of PA (aldosterone-producing adenoma or bilateral adrenal hyperplasia) requires clarification. In this review, we discuss the studies performed to date on AT1R-Abs in PA.
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Affiliation(s)
- Lucie S. Meyer
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität
München, LMU München, Germany
| | - Siyuan Gong
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität
München, LMU München, Germany
| | - Martin Reincke
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität
München, LMU München, Germany
| | - Tracy Ann Williams
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität
München, LMU München, Germany
- Division of Internal Medicine and Hypertension, Department of Medical
Sciences, University of Turin, Turin, Italy
- Correspondence Tracy Ann Williams PhD Medizinische Klinik und Poliklinik IV, Klinikum der
UniversitätMünchen, LMU MünchenZiemssenstr. 180336 MünchenGermany+49 89 4400 52941+49 89 4400 54428
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