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Jenei-Lanzl Z, Straub RH. β2-adrenoceptors kick osteoarthritis - Time to rethink prevention and therapy. Osteoarthritis Cartilage 2024:S1063-4584(24)01268-8. [PMID: 38945292 DOI: 10.1016/j.joca.2024.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 05/13/2024] [Accepted: 06/24/2024] [Indexed: 07/02/2024]
Abstract
Although, during the past decades, substantial advances emerged in identifying major local and systemic factors contributing to initiation and progression of osteoarthritis (OA), some neuroendocrine mechanisms are still not understood or even neglected when thinking about novel therapeutic options. One of which is the sympathetic nervous system that exhibits various OA-promoting effects in different tissues of the joint. Interestingly, the β2-adrenoceptor (AR) mediates the majority of these effects as demonstrated by several in vitro, in vivo as well as in clinical studies. This review article does not only summarize studies of the past two decades demonstrating that the β2-AR plays an OA-promoting role in different tissues of the joint but also aims to encourage the reader to think about next-level research to discover novel and innovative preventive and/or therapeutic strategies targeting the β2-AR in OA.
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Affiliation(s)
- Zsuzsa Jenei-Lanzl
- Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Department of Trauma Surgery and Orthopedics, Goethe University Frankfurt, University Hospital, Frankfurt am Main, Germany.
| | - Rainer H Straub
- Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Department of Internal Medicine, University Hospital Regensburg, Regensburg, Germany.
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2
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Özçete ÖD, Banerjee A, Kaeser PS. Mechanisms of neuromodulatory volume transmission. Mol Psychiatry 2024:10.1038/s41380-024-02608-3. [PMID: 38789677 DOI: 10.1038/s41380-024-02608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
A wealth of neuromodulatory transmitters regulate synaptic circuits in the brain. Their mode of signaling, often called volume transmission, differs from classical synaptic transmission in important ways. In synaptic transmission, vesicles rapidly fuse in response to action potentials and release their transmitter content. The transmitters are then sensed by nearby receptors on select target cells with minimal delay. Signal transmission is restricted to synaptic contacts and typically occurs within ~1 ms. Volume transmission doesn't rely on synaptic contact sites and is the main mode of monoamines and neuropeptides, important neuromodulators in the brain. It is less precise than synaptic transmission, and the underlying molecular mechanisms and spatiotemporal scales are often not well understood. Here, we review literature on mechanisms of volume transmission and raise scientific questions that should be addressed in the years ahead. We define five domains by which volume transmission systems can differ from synaptic transmission and from one another. These domains are (1) innervation patterns and firing properties, (2) transmitter synthesis and loading into different types of vesicles, (3) architecture and distribution of release sites, (4) transmitter diffusion, degradation, and reuptake, and (5) receptor types and their positioning on target cells. We discuss these five domains for dopamine, a well-studied monoamine, and then compare the literature on dopamine with that on norepinephrine and serotonin. We include assessments of neuropeptide signaling and of central acetylcholine transmission. Through this review, we provide a molecular and cellular framework for volume transmission. This mechanistic knowledge is essential to define how neuromodulatory systems control behavior in health and disease and to understand how they are modulated by medical treatments and by drugs of abuse.
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Affiliation(s)
- Özge D Özçete
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Aditi Banerjee
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
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3
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Ma C, Zhang Y, Cao Y, Hu CH, Zheng CX, Jin Y, Sui BD. Autonomic neural regulation in mediating the brain-bone axis: mechanisms and implications for regeneration under psychological stress. QJM 2024; 117:95-108. [PMID: 37252831 DOI: 10.1093/qjmed/hcad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Indexed: 06/01/2023] Open
Abstract
Efficient regeneration of bone defects caused by disease or significant trauma is a major challenge in current medicine, which is particularly difficult yet significant under the emerging psychological stress in the modern society. Notably, the brain-bone axis has been proposed as a prominent new concept in recent years, among which autonomic nerves act as an essential and emerging skeletal pathophysiological factor related to psychological stress. Studies have established that sympathetic cues lead to impairment of bone homeostasis mainly through acting on mesenchymal stem cells (MSCs) and their derivatives with also affecting the hematopoietic stem cell (HSC)-lineage osteoclasts, and the autonomic neural regulation of stem cell lineages in bone is increasingly recognized to contribute to the bone degenerative disease, osteoporosis. This review summarizes the distribution characteristics of autonomic nerves in bone, introduces the regulatory effects and mechanisms of autonomic nerves on MSC and HSC lineages, and expounds the crucial role of autonomic neural regulation on bone physiology and pathology, which acts as a bridge between the brain and the bone. With the translational perspective, we further highlight the autonomic neural basis of psychological stress-induced bone loss and a series of pharmaceutical therapeutic strategies and implications toward bone regeneration. The summary of research progress in this field will add knowledge to the current landscape of inter-organ crosstalk and provide a medicinal basis for the achievement of clinical bone regeneration in the future.
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Affiliation(s)
- C Ma
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Y Zhang
- Department of Medical Rehabilitation, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Y Cao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - C-H Hu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Xi'an Institute of Tissue Engineering and Regenerative Medicine, Xi'an, Shaanxi 710032, China
| | - C-X Zheng
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Y Jin
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Xi'an Institute of Tissue Engineering and Regenerative Medicine, Xi'an, Shaanxi 710032, China
| | - B-D Sui
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
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4
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Madhu MK, Shewani K, Murarka RK. Biased Signaling in Mutated Variants of β 2-Adrenergic Receptor: Insights from Molecular Dynamics Simulations. J Chem Inf Model 2024; 64:449-469. [PMID: 38194225 DOI: 10.1021/acs.jcim.3c01481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
The molecular basis of receptor bias in G protein-coupled receptors (GPCRs) caused by mutations that preferentially activate specific intracellular transducers over others remains poorly understood. Two experimentally identified biased variants of β2-adrenergic receptors (β2AR), a prototypical GPCR, are a triple mutant (T68F, Y132A, and Y219A) and a single mutant (Y219A); the former bias the receptor toward the β-arrestin pathway by disfavoring G protein engagement, while the latter induces G protein signaling explicitly due to selection against GPCR kinases (GRKs) that phosphorylate the receptor as a prerequisite of β-arrestin binding. Though rigorous characterizations have revealed functional implications of these mutations, the atomistic origin of the observed transducer selectivity is not clear. In this study, we investigated the allosteric mechanism of receptor bias in β2AR using microseconds of all-atom Gaussian accelerated molecular dynamics (GaMD) simulations. Our observations reveal distinct rearrangements in transmembrane helices, intracellular loop 3, and critical residues R1313.50 and Y3267.53 in the conserved motifs D(E)RY and NPxxY for the mutant receptors, leading to their specific transducer interactions. Moreover, partial dissociation of G protein from the receptor core is observed in the simulations of the triple mutant in contrast to the single mutant and wild-type receptor. The reorganization of allosteric communications from the extracellular agonist BI-167107 to the intracellular receptor-transducer interfaces drives the conformational rearrangements responsible for receptor bias in the single and triple mutants. The molecular insights into receptor bias of β2AR presented here could improve the understanding of biased signaling in GPCRs, potentially opening new avenues for designing novel therapeutics with fewer side-effects and superior efficacy.
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Affiliation(s)
- Midhun K Madhu
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh 462066, India
| | - Kunal Shewani
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh 462066, India
| | - Rajesh K Murarka
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal, Madhya Pradesh 462066, India
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5
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Dangat Y, Freindorf M, Kraka E. Mechanistic Insights into S-Depalmitolyse Activity of Cln5 Protein Linked to Neurodegeneration and Batten Disease: A QM/MM Study. J Am Chem Soc 2024; 146:145-158. [PMID: 38055807 DOI: 10.1021/jacs.3c06397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Ceroid lipofuscinosis neuronal protein 5 (Cln5) is encoded by the CLN5 gene. The genetic variants of this gene are associated with the CLN5 form of Batten disease. Recently, the first crystal structure of Cln5 was reported. Cln5 shows cysteine palmitoyl thioesterase S-depalmitoylation activity, which was explored via fluorescent emission spectroscopy utilizing the fluorescent probe DDP-5. In this work, the mechanism of the reaction between Cln5 and DDP-5 was studied computationally by applying a QM/MM methodology at the ωB97X-D/6-31G(d,p):AMBER level. The results of our study clearly demonstrate the critical role of the catalytic triad Cys280-His166-Glu183 in S-depalmitoylation activity. This is evidenced through a comparison of the pathways catalyzed by the Cys280-His166-Glu183 triad and those with only Cys280 involved. The computed reaction barriers are in agreement with the catalytic efficiency. The calculated Gibb's free-energy profile suggests that S-depalmitoylation is a rate-limiting step compared to the preceding S-palmitoylation, with barriers of 26.1 and 25.3 kcal/mol, respectively. The energetics were complemented by monitoring the fluctuations in the electron density distribution through NBO charges and bond strength alterations via local mode stretching force constants during the catalytic pathways. This comprehensive protocol led to a more holistic picture of the reaction mechanism at the atomic level. It forms the foundation for future studies on the effects of gene mutations on both the S-palmitoylation and S-depalmitoylation steps, providing valuable data for the further development of enzyme replacement therapy, which is currently the only FDA-approved therapy for childhood neurodegenerative diseases, including Batten disease.
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Affiliation(s)
- Yuvraj Dangat
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Marek Freindorf
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Elfi Kraka
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
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6
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Ziqubu K, Dludla PV, Mabhida SE, Jack BU, Keipert S, Jastroch M, Mazibuko-Mbeje SE. Brown adipose tissue-derived metabolites and their role in regulating metabolism. Metabolism 2024; 150:155709. [PMID: 37866810 DOI: 10.1016/j.metabol.2023.155709] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/28/2023] [Accepted: 10/14/2023] [Indexed: 10/24/2023]
Abstract
The discovery and rejuvenation of metabolically active brown adipose tissue (BAT) in adult humans have offered a new approach to treat obesity and metabolic diseases. Beyond its accomplished role in adaptive thermogenesis, BAT secretes signaling molecules known as "batokines", which are instrumental in regulating whole-body metabolism via autocrine, paracrine, and endocrine action. In addition to the intrinsic BAT metabolite-oxidizing activity, the endocrine functions of these molecules may help to explain the association between BAT activity and a healthy systemic metabolic profile. Herein, we review the evidence that underscores the significance of BAT-derived metabolites, especially highlighting their role in controlling physiological and metabolic processes involving thermogenesis, substrate metabolism, and other essential biological processes. The conversation extends to their capacity to enhance energy expenditure and mitigate features of obesity and its related metabolic complications. Thus, metabolites derived from BAT may provide new avenues for the discovery of metabolic health-promoting drugs with far-reaching impacts. This review aims to dissect the complexities of the secretory role of BAT in modulating local and systemic metabolism in metabolic health and disease.
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Affiliation(s)
- Khanyisani Ziqubu
- Department of Biochemistry, North-West University, Mmabatho 2745, South Africa
| | - Phiwayinkosi V Dludla
- Cochrane South Africa, South African Medical Research Council, Tygerberg 7505, South Africa; Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa
| | - Sihle E Mabhida
- Non-Communicable Diseases Research Unit, South African Medical Research Council, Tygerberg 7505, South Africa
| | - Babalwa U Jack
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg 7505, South Africa
| | - Susanne Keipert
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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7
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Kurban N, Qin Y, Zhao HL, Hu X, Chen X, Zhao YY, Peng YS, Wang HB, Cui SY, Zhang YH. Chronic Stress-Induced Elevation of Melanin-Concentrating Hormone in the Locus Coeruleus Inhibits Norepinephrine Production and Associated With Depression-Like Behaviors in Rats. Int J Neuropsychopharmacol 2024; 27:pyad069. [PMID: 38135278 PMCID: PMC10799331 DOI: 10.1093/ijnp/pyad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that projects throughout the central nervous system, including the noradrenergic locus coeruleus (LC). Our previous study suggested that MCH/MCH receptor 1 (MCHR1) in the LC may be involved in the regulation of depression. The present study investigated whether the role of MCH/MCHR1 in the LC in depression-like behaviors is associated with the regulation of norepinephrine. METHOD Chronic unpredictable stress (CUS) and an acute intra-LC microinjection of MCH induced depression-like behaviors in rats. The MCHR1 antagonist SNAP-94847 was also microinjected in the LC in rats that were suffering CUS or treated with MCH. The sucrose preference, forced swim, and locomotor tests were used for behavioral evaluation. Immunofluorescence staining, enzyme-linked immunosorbent assay, western blot, and high-performance liquid chromatography with electrochemical detection were used to explore the mechanism of MCH/MCHR1 in the regulation of depression-like behaviors. RESULTS CUS induced an abnormal elevation of MCH levels and downregulated MCHR1 in the LC, which was highly correlated with the formation of depression-like behaviors. SNAP-94847 exerted antidepressant effects in CUS-exposed rats by normalizing tyrosine hydroxylase, dopamine β hydroxylase, and norepinephrine in the LC. An acute microinjection of MCH induced depression-like behaviors through its action on MCHR1. MCHR1 antagonism in the LC significantly reversed the MCH-induced downregulation of norepinephrine production by normalizing MCHR1-medicated cAMP-PKA signaling. CONCLUSIONS Our study confirmed that the MCH/MCHR1 system in the LC may be involved in depression-like behaviors by downregulating norepinephrine production. These results improve our understanding of the pathogenesis of depression that is related to the MCH/MCHR1 system in the LC.
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Affiliation(s)
- Nurhumar Kurban
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Yu Qin
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Hui-Ling Zhao
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Xiao Hu
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Xi Chen
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Yi-Yi Zhao
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Yu-Shuo Peng
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Hong-Bo Wang
- Key Laboratory of Molecular Pharmacology and Drug Evaluation, Ministry of Education, Yantai University, Yantai, China
| | - Su-Ying Cui
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
- Key Laboratory of Molecular Pharmacology and Drug Evaluation, Ministry of Education, Yantai University, Yantai, China
| | - Yong-He Zhang
- Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing, China
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8
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Kleinau G, Ali AH, Wiechert F, Szczepek M, Schmidt A, Spahn CMT, Liebscher I, Schöneberg T, Scheerer P. Intramolecular activity regulation of adhesion GPCRs in light of recent structural and evolutionary information. Pharmacol Res 2023; 197:106971. [PMID: 38032292 DOI: 10.1016/j.phrs.2023.106971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
The class B2 of GPCRs known as adhesion G protein-coupled receptors (aGPCRs) has come under increasing academic and nonacademic research focus over the past decade due to their physiological importance as mechano-sensors in cell-cell and cell-matrix contexts. A major advance in understanding signal transduction of aGPCRs was achieved by the identification of the so-called Stachel sequence, which acts as an intramolecular agonist at the interface between the N terminus (Nt) and the seven-transmembrane helix domain (7TMD). Distinct extracellular signals received by the Nt are integrated at the Stachel into structural changes of the 7TMD towards an active state conformation. Until recently, little information was available on how the activation process of aGPCRs is realized at the molecular level. In the past three years several structures of the 7TMD plus the Stachel in complex with G proteins have been determined, which provide new insights into the architecture and molecular function of this receptor class. Herein, we review this structural information to extract common and distinct aGPCR features with particular focus on the Stachel binding site within the 7TMD. Our analysis extends the current view of aGPCR activation and exposes similarities and differences not only between diverse aGPCR members, but also compared to other GPCR classes.
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Affiliation(s)
- Gunnar Kleinau
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany
| | - Amal Hassan Ali
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany
| | - Franziska Wiechert
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Michal Szczepek
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany
| | - Andrea Schmidt
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany
| | - Christian M T Spahn
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103 Leipzig, Germany; School of Medicine, University of Global Health Equity (UGHE), Kigali, Rwanda.
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.
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9
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Yang PC, Rose A, DeMarco KR, Dawson JRD, Han Y, Jeng MT, Harvey RD, Santana LF, Ripplinger CM, Vorobyov I, Lewis TJ, Clancy CE. A multiscale predictive digital twin for neurocardiac modulation. J Physiol 2023; 601:3789-3812. [PMID: 37528537 PMCID: PMC10528740 DOI: 10.1113/jp284391] [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: 01/17/2023] [Accepted: 07/11/2023] [Indexed: 08/03/2023] Open
Abstract
Cardiac function is tightly regulated by the autonomic nervous system (ANS). Activation of the sympathetic nervous system increases cardiac output by increasing heart rate and stroke volume, while parasympathetic nerve stimulation instantly slows heart rate. Importantly, imbalance in autonomic control of the heart has been implicated in the development of arrhythmias and heart failure. Understanding of the mechanisms and effects of autonomic stimulation is a major challenge because synapses in different regions of the heart result in multiple changes to heart function. For example, nerve synapses on the sinoatrial node (SAN) impact pacemaking, while synapses on contractile cells alter contraction and arrhythmia vulnerability. Here, we present a multiscale neurocardiac modelling and simulator tool that predicts the effect of efferent stimulation of the sympathetic and parasympathetic branches of the ANS on the cardiac SAN and ventricular myocardium. The model includes a layered representation of the ANS and reproduces firing properties measured experimentally. Model parameters are derived from experiments and atomistic simulations. The model is a first prototype of a digital twin that is applied to make predictions across all system scales, from subcellular signalling to pacemaker frequency to tissue level responses. We predict conditions under which autonomic imbalance induces proarrhythmia and can be modified to prevent or inhibit arrhythmia. In summary, the multiscale model constitutes a predictive digital twin framework to test and guide high-throughput prediction of novel neuromodulatory therapy. KEY POINTS: A multi-layered model representation of the autonomic nervous system that includes sympathetic and parasympathetic branches, each with sparse random intralayer connectivity, synaptic dynamics and conductance based integrate-and-fire neurons generates firing patterns in close agreement with experiment. A key feature of the neurocardiac computational model is the connection between the autonomic nervous system and both pacemaker and contractile cells, where modification to pacemaker frequency drives initiation of electrical signals in the contractile cells. We utilized atomic-scale molecular dynamics simulations to predict the association and dissociation rates of noradrenaline with the β-adrenergic receptor. Multiscale predictions demonstrate how autonomic imbalance may increase proclivity to arrhythmias or be used to terminate arrhythmias. The model serves as a first step towards a digital twin for predicting neuromodulation to prevent or reduce disease.
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Affiliation(s)
- Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | - Adam Rose
- Department of Mathematics, University of California Davis, Davis, CA
| | - Kevin R. DeMarco
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | - John R. D. Dawson
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | - Yanxiao Han
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | - Mao-Tsuen Jeng
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | | | - L. Fernando Santana
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | | | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
| | - Timothy J. Lewis
- Department of Mathematics, University of California Davis, Davis, CA
| | - Colleen E. Clancy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA
- Center for Precision Medicine and Data Science, University of California Davis, Sacramento, CA
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10
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Zhou H, Wang K, Xu Z, Liu D, Wang Y, Guo M. Chronic unpredictable stress induces depression/anxiety-related behaviors and alterations of hippocampal monoamine receptor mRNA expression in female mice at different ages. Heliyon 2023; 9:e18369. [PMID: 37539192 PMCID: PMC10393760 DOI: 10.1016/j.heliyon.2023.e18369] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 08/05/2023] Open
Abstract
Depression and anxiety are the most common mental health disorders. Though they affect people at any age and occur more often in females, the pathophysiological changes under these conditions are less investigated. In the present study, we examined the effects of age and stress on depression- and anxiety-related behaviors in female mice. Saccharin preference and the open field test were carried out before and after chronic unpredictable stress in 4-, 14- and 25-month-old female mice. After behavioral tests, mRNA levels of monoamine receptors in the hippocampus were measured by real-time RT-PCR. Chronic unpredictable stress decreased saccharin preference in 4-, 14- and 25-month-old mice and the time spent in the center in the open field test in 25-month-old mice. For monoamine receptors, analysis of variance revealed significant effects of age on mRNA levels of Htr1a, Htr2a, Htr6, Adra1a, Adrb2, and Adrb3, significant effects of stress on mRNA levels of Htr4, Adra2c, Adrb1, and Adrb2, and interactions of age × stress on mRNA levels of Htr1a, Htr5b, Adra1d, Adra2a, Adra2c, and Adrb1. Chronic unpredictable stress decreased mRNA levels of Htr4, Htr5b, Adra2c, and Adrb1 in 4-month-old female mice. Correlations were observed between saccharin preference and mRNA levels of Htr4, Htr5b, Htr6, Adra1d, Adra2a, and Adra2c in 4-month-old mice and between the time spent in the center in the open field test and mRNA levels of Htr1b in 4-month-old mice, Htr3a, Htr7, and Adrb2 in 14-month-old mice, and Drd2 in 4- and 14-month-old mice. Our findings support that stress induces depression- and anxiety-related behaviors and the expression of hippocampal monoamine receptors in an age-dependent manner in female mice.
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Affiliation(s)
- Han Zhou
- Department of Psychology, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
| | - Kaixin Wang
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
| | - Zhicheng Xu
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
| | - Dunjiang Liu
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
| | - Yameng Wang
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
| | - Ming Guo
- Department of Psychology, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
- Medical Research Center, Binzhou Medical University Hospital, The First School of Clinical Medicine of Binzhou Medical University, Binzhou, Shandong, 256603, China
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11
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Tricomi J, Landini L, Nieddu V, Cavallaro U, Baker JG, Papakyriakou A, Richichi B. Rational design, synthesis, and pharmacological evaluation of a cohort of novel beta-adrenergic receptors ligands enables an assessment of structure-activity relationships. Eur J Med Chem 2023; 246:114961. [PMID: 36495629 DOI: 10.1016/j.ejmech.2022.114961] [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: 10/05/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 11/30/2022]
Abstract
Biomedical applications of molecules that are able to modulate β-adrenergic signaling have become increasingly attractive over the last decade, revealing that β-adrenergic receptors (β-ARs) are key targets for a plethora of therapeutic interventions, including cancer. Despite successes in β-AR drug discovery, identification of β-AR ligands that are useful as selective chemical tools in pharmacological studies of the three β-AR subtypes, or lead compounds for drug development is still a highly challenging task. This is mainly due to the intrinsic plasticity of β-ARs as G protein-coupled receptors in conjunction with the requirement for functional receptor subtype selectivity, tissue specificity and minimal off-target effects. With the aim to provide insight into structure-activity relationships for the three β-AR subtypes, we have synthesized and obtained the pharmacological profile of a series of structurally diverse compounds (named MC) that were designed based on the aryloxy-propanolamine scaffold of SR59230A. Comparative analysis of their predicted binding mode within the active and inactive states of the receptors in combination with their pharmacological profile revealed key structural elements that control their activity as agonists or antagonists, in addition to clues about substituents that mediate selectivity for one receptor subtype over the others. We anticipate that these results will facilitate selective β-AR drug development efforts.
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Affiliation(s)
- Jacopo Tricomi
- Department of Chemistry, University of Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy
| | - Luca Landini
- Department of Chemistry, University of Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy; Institute of Biosciences and Applications, National Centre for Scientific Research "Demokritos", 15341 Agia Paraskevi, Athens, Greece
| | - Valentina Nieddu
- Unit of Gynaecological Oncology Research, European Institute of Oncology IRCCS, Milan, Italy
| | - Ugo Cavallaro
- Unit of Gynaecological Oncology Research, European Institute of Oncology IRCCS, Milan, Italy
| | - Jillian G Baker
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Athanasios Papakyriakou
- Institute of Biosciences and Applications, National Centre for Scientific Research "Demokritos", 15341 Agia Paraskevi, Athens, Greece.
| | - Barbara Richichi
- Department of Chemistry, University of Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy.
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12
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Helmer N, Wolf S, Stock G. Energy Transport and Its Function in Heptahelical Transmembrane Proteins. J Phys Chem B 2022; 126:8735-8746. [PMID: 36261792 DOI: 10.1021/acs.jpcb.2c05892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Photoproteins such as bacteriorhodopsin (bR) and rhodopsin (Rho) need to effectively dissipate photoinduced excess energy to prevent themselves from damage. Another well-studied seven transmembrane (TM) helices protein is the β2 adrenergic receptor (β2AR), a G protein-coupled receptor for which energy dissipation paths have been linked with allosteric communication. To study the vibrational energy transport in the active and inactive states of these proteins, a master equation approach [J. Chem. Phys.2020, 152, 045103] is employed, which uses scaling rules that allow us to calculate energy transport rates solely based on the protein structure. Despite their overall structural similarity, the three 7TM proteins reveal quite different strategies to redistribute excess energy. While bR quickly removes the energy using the TM7 helix as a "lightning rod", Rho exhibits a rather poor energy dissipation, which might eventually require the hydrolysis of the Schiff base between the protein and the retinal chromophore to prevent overheating. Heating the ligand adrenaline of β2AR, the resulting energy transport network of the protein is found to change significantly upon switching from the active state to the inactive state. While the energy flow may highlight aspects of the inter-residue couplings of β2AR, it seems not particularly suited to explain allosteric phenomena.
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Affiliation(s)
- Nadja Helmer
- Biomolecular Dynamics, Institute of Physics, University of Freiburg, 79104Freiburg, Germany
| | - Steffen Wolf
- Biomolecular Dynamics, Institute of Physics, University of Freiburg, 79104Freiburg, Germany
| | - Gerhard Stock
- Biomolecular Dynamics, Institute of Physics, University of Freiburg, 79104Freiburg, Germany
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13
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Cloning of Grass Carp Chemokine XC Receptor 1 (XCR1) Gene and Evaluation of Its Expression in Various Organs after GCRV Infection. FISHES 2022. [DOI: 10.3390/fishes7030130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Interaction between the chemokine receptor XCR1 and its ligand is closely related to the immune function in animals; however, there are only a few reports on role of XCR1 in the immune system of fish. We aimed to analyze the expression of XCR1 in various organs or tissues of grass carp before and after Grass Carp Reovirus (GCRV) infection to better understand the function of XCR1 in resistance to GCRV infection. We cloned and sequenced the cDNA of grass carp XCR1 and analyzed the molecular structure of XCR1 based its amino acid sequence. Further, we analyzed the relative expression levels of XCR1 in different organs or tissues of male parent grass carp with GCRV resistance (P1) and their first-generation offspring (F1) before and after GCRV infection. Our results show that the total length of cDNA of the grass carp XCR1 gene is 1659 bp and encodes 365 amino acids. XCR1 contains seven conserved transmembrane helical domains. The homologous tertiary structure of XCR1 is similar to its homologs in other species. After artificial GCRV infection, there were significant differences in the expression of the grass carp XCR1 gene in different tissues, at different time points, and between P1 and F1 fish. These results will contribute to our understanding of the role of XCR1 in fish immune responses and contribute to the development of GCRV-resistant grass carp.
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14
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Xu X, Wu G. Human C1orf27 protein interacts with α 2A-adrenergic receptor and regulates its anterograde transport. J Biol Chem 2022; 298:102021. [PMID: 35551911 PMCID: PMC9168726 DOI: 10.1016/j.jbc.2022.102021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
The molecular mechanisms underlying the anterograde surface transport of G protein–coupled receptors (GPCRs) after their synthesis in the endoplasmic reticulum (ER) are not well defined. In C. elegans, odorant response abnormal 4 has been implicated in the delivery of olfactory GPCRs to the cilia of chemosensory neurons. However, the function and regulation of its human homolog, C1orf27, in GPCR transport or in general membrane trafficking remain unknown. Here, we demonstrate that siRNA-mediated knockdown of C1orf27 markedly impedes the ER-to-Golgi export kinetics of newly synthesized α2A-adrenergic receptor (α2A-AR), a prototypic GPCR, with the half-time being prolonged by more than 65%, in mammalian cells in retention using the selective hooks assays. Using modified bioluminescence resonance energy transfer assays and ELISAs, we also show that C1orf27 knockdown significantly inhibits the surface transport of α2A-AR. Similarly, C1orf27 knockout by CRISPR-Cas9 markedly suppresses the ER–Golgi-surface transport of α2A-AR. In addition, we demonstrate that C1orf27 depletion attenuates the export of β2-AR and dopamine D2 receptor but not of epidermal growth factor receptor. We further show that C1orf27 physically associates with α2A-AR, specifically via its third intracellular loop and C terminus. Taken together, these data demonstrate an important role of C1orf27 in the trafficking of nascent GPCRs from the ER to the cell surface through the Golgi and provide novel insights into the regulation of the biosynthesis and anterograde transport of the GPCR family members.
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Affiliation(s)
- Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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15
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Reiter E. [β-arrestins, their mechanisms of action and multiple roles in the biology of G protein-coupled receptors]. Biol Aujourdhui 2022; 215:107-118. [PMID: 35275055 DOI: 10.1051/jbio/2021010] [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: 09/07/2021] [Indexed: 06/14/2023]
Abstract
The stimulation of G protein-coupled receptors (GPCRs) induces biological responses to a wide range of extracellular cues. The heterotrimeric G proteins, which are recruited to the active conformation of GPCRs, lead to the generation of various diffusible second messengers. Only two other families of proteins exhibit the remarkable characteristic of recognizing and binding to the active conformation of most GPCRs: GPCR kinases (GRKs) and β-arrestins. These two families of proteins were initially identified as key players in the desensitization of G protein activation by GPCRs. Over the years, β-arrestins have been implicated in an increasing number of interactions with non-receptor proteins, expanding the range of cellular functions in which they are involved. It is now well established that β-arrestins, by scaffolding and recruiting protein complexes in an agonist-dependent manner, directly regulate the trafficking and signaling of GPCRs. Remarkable advances have been made in recent years which have made it possible i) to identify biased ligands capable, by stabilizing particular conformations of a growing number of GPCRs, of activating or blocking the action of β-arrestins independently of that of G proteins, some of these ligands holding great therapeutic interest; ii) to demonstrate β-arrestins' role in the compartmentalization of GPCR signaling within the cell, and iii) to understand the molecular details of their interaction with GPCRs and of their activation through structural and biophysical approaches.
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Affiliation(s)
- Eric Reiter
- CNRS, IFCE, INRAE, Université de Tours, PRC, 37380 Nouzilly, France - Inria, Centre de recherche Inria Saclay-Île-de-France, 91120 Palaiseau, France
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16
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Chandler B, Todd L, Smith SO. Magic angle spinning NMR of G protein-coupled receptors. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 128:25-43. [PMID: 35282868 PMCID: PMC10718405 DOI: 10.1016/j.pnmrs.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 06/14/2023]
Abstract
G protein-coupled receptors (GPCRs) have a simple seven transmembrane helix architecture which has evolved to recognize a diverse number of chemical signals. The more than 800 GPCRs encoded in the human genome function as receptors for vision, smell and taste, and mediate key physiological processes. Consequently, these receptors are a major target for pharmaceuticals. Protein crystallography and electron cryo-microscopy have provided high resolution structures of many GPCRs in both active and inactive conformations. However, these structures have not sparked a surge in rational drug design, in part because GPCRs are inherently dynamic and the structural changes induced by ligand or drug binding to stabilize inactive or active conformations are often subtle rearrangements in packing or hydrogen-bonding interactions. NMR spectroscopy provides a sensitive probe of local structure and dynamics at specific sites within these receptors as well as global changes in receptor structure and dynamics. These methods can also capture intermediate states and conformations with low populations that provide insights into the activation pathways. We review the use of solid-state magic angle spinning NMR to address the structure and activation mechanisms of GPCRs. The focus is on the large and diverse class A family of receptors. We highlight three specific class A GPCRs in order to illustrate how solid-state, as well as solution-state, NMR spectroscopy can answer questions in the field involving how different GPCR classes and subfamilies are activated by their associated ligands, and how small molecule drugs can modulate GPCR activation.
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Affiliation(s)
- Bianca Chandler
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Lauren Todd
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
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17
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Ujiantari NSO, Ham S, Nagiri C, Shihoya W, Nureki O, Hutchinson D, Schuster D. Pharmacophore-guided Virtual Screening to Identify New β3-Adrenergic Receptor Agonists. Mol Inform 2021; 41:e2100223. [PMID: 34963040 PMCID: PMC9400856 DOI: 10.1002/minf.202100223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/18/2021] [Indexed: 11/21/2022]
Abstract
The β3‐adrenergic receptor (β3‐AR) is found in several tissues such as adipose tissue and urinary bladder. It is a therapeutic target because it plays a role in thermogenesis, lipolysis, and bladder relaxation. Two β3‐AR agonists are used clinically: mirabegron 1 and vibegron 2, which are indicated for overactive bladder syndrome. However, these drugs show adverse effects, including increased blood pressure in mirabegron patients. Hence, new β3‐AR agonists are needed as starting points for drug development. Previous pharmacophore modeling studies of the β3‐AR did not involve experimental in vitro validation. Therefore, this study aimed to conduct prospective virtual screening and confirm the biological activity of virtual hits. Ligand‐based pharmacophore modeling was performed since no 3D structure of human β3‐AR is yet available. A dataset consisting of β3‐AR agonists was prepared to build and validate the pharmacophore models. The best model was employed for prospective virtual screening, followed by physicochemical property filtering and a docking evaluation. To confirm the activity of the virtual hits, an in vitro assay was conducted, measuring cAMP levels at the cloned β3‐AR. Out of 35 tested compounds, 4 compounds were active in CHO−K1 cells expressing the human β3‐AR, and 8 compounds were active in CHO−K1 cells expressing the mouse β3‐AR.
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18
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Schoof M, Wang L, Cogan JZ, Lawrence RE, Boone M, Wuerth JD, Frost A, Walter P. Viral evasion of the integrated stress response through antagonism of eIF2-P binding to eIF2B. Nat Commun 2021; 12:7103. [PMID: 34876554 PMCID: PMC8651678 DOI: 10.1038/s41467-021-26164-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/17/2021] [Indexed: 01/07/2023] Open
Abstract
Viral infection triggers activation of the integrated stress response (ISR). In response to viral double-stranded RNA (dsRNA), RNA-activated protein kinase (PKR) phosphorylates the translation initiation factor eIF2, converting it from a translation initiator into a potent translation inhibitor and this restricts the synthesis of viral proteins. Phosphorylated eIF2 (eIF2-P) inhibits translation by binding to eIF2's dedicated, heterodecameric nucleotide exchange factor eIF2B and conformationally inactivating it. We show that the NSs protein of Sandfly Fever Sicilian virus (SFSV) allows the virus to evade the ISR. Mechanistically, NSs tightly binds to eIF2B (KD = 30 nM), blocks eIF2-P binding, and rescues eIF2B GEF activity. Cryo-EM structures demonstrate that SFSV NSs and eIF2-P directly compete, with the primary NSs contacts to eIF2Bα mediated by five 'aromatic fingers'. NSs binding preserves eIF2B activity by maintaining eIF2B's conformation in its active A-State.
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Affiliation(s)
- Michael Schoof
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Lan Wang
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - J Zachery Cogan
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Rosalie E Lawrence
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | - Morgane Boone
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
| | | | - Adam Frost
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Peter Walter
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, USA.
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19
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Smith SO. Deconstructing the transmembrane core of class A G protein-coupled receptors. Trends Biochem Sci 2021; 46:1017-1029. [PMID: 34538727 PMCID: PMC8595765 DOI: 10.1016/j.tibs.2021.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 01/14/2023]
Abstract
Class A G protein-coupled receptors have evolved to recognize ligands ranging from small-molecule odorants to proteins. Although they are among the most diverse membrane receptors in eukaryotic organisms, they possess a highly conserved core within their seven-transmembrane helix framework. The conservation of the transmembrane core has led to the idea of a common mechanism by which ligand binding is coupled to the outward rotation of helix H6, the hallmark of an active receptor. Nevertheless, there is still no consensus on the mechanism of coupling or on the roles of specific residues within the core. Recent insights from crystallography and NMR spectroscopy provide a way to decompose the core into its essential structural and functional elements that shed new light on this important region.
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Affiliation(s)
- Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.
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20
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Rivera-Ortiz J, Pla-Tenorio J, Cruz ML, Colon K, Perez-Morales J, Rodriguez JA, Martinez-Sicari J, Noel RJ. Blockade of beta adrenergic receptors protects the blood brain barrier and reduces systemic pathology caused by HIV-1 Nef protein. PLoS One 2021; 16:e0259446. [PMID: 34784367 PMCID: PMC8594844 DOI: 10.1371/journal.pone.0259446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/19/2021] [Indexed: 01/14/2023] Open
Abstract
Combination antiretroviral therapy (cART) targets viral replication, but early viral protein production by astrocytes may still occur and contribute to the progression of HIV-1 associated neurocognitive disorders and secondary complications seen in patients receiving cART. In prior work with our model, astrocytic HIV-1 Nef expression exhibits neurotoxic effects leading to neurological damage, learning impairment, and immune upregulation that induces inflammation in the lungs and small intestine (SI). In this follow-up study, we focus on the sympathetic nervous system (SNS) as the important branch for peripheral inflammation resulting from astrocytic Nef expression. Male and female Sprague Dawley rats were infused with transfected astrocytes to produce Nef. The rats were divided in four groups: Nef, Nef + propranolol, propranolol and naïve. The beta-adrenergic blocker, propranolol, was administered for 3 consecutive days, starting one day prior to surgery. Two days after the surgery, the rats were sacrificed, and then blood, brain, small intestine (SI), and lung tissues were collected. Levels of IL-1β were higher in both male and female rats, and treatment with propranolol restored IL-1β to basal levels. We observed that Nef expression decreased staining of the tight junction protein claudin-5 in brain tissue while animals co-treated with propranolol restored claudin-5 expression. Lungs and SI of rats in the Nef group showed histological signs of damage including larger Peyer's Patches, increased tissue thickness, and infiltration of immune cells; these findings were abrogated by propranolol co-treatment. Results suggest that interruption of the beta adrenergic signaling reduces the peripheral organ inflammation caused after Nef expression in astrocytes of the brain.
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Affiliation(s)
- Jocelyn Rivera-Ortiz
- HIV-1 Immunopathogenesis Laboratory, The Wistar Institute, Philadelphia, PA, United States of America
| | - Jessalyn Pla-Tenorio
- Department of Basic Sciences, Ponce Health Sciences University, Ponce Research Institute, Ponce, Puerto Rico
| | - Myrella L. Cruz
- Department of Basic Sciences, Ponce Health Sciences University, Ponce Research Institute, Ponce, Puerto Rico
| | - Krystal Colon
- HIV-1 Immunopathogenesis Laboratory, The Wistar Institute, Philadelphia, PA, United States of America
| | - Jaileene Perez-Morales
- Department of Basic Sciences, Ponce Health Sciences University, Ponce Research Institute, Ponce, Puerto Rico
| | - Julio A. Rodriguez
- Cooper University Hospital Department of Orthopaedic Surgery, Camden, NJ, United States of America
| | - Jorge Martinez-Sicari
- Department of Basic Sciences, Ponce Health Sciences University, Ponce Research Institute, Ponce, Puerto Rico
| | - Richard J. Noel
- Department of Basic Sciences, Ponce Health Sciences University, Ponce Research Institute, Ponce, Puerto Rico
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21
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Structures of active melanocortin-4 receptor-Gs-protein complexes with NDP-α-MSH and setmelanotide. Cell Res 2021; 31:1176-1189. [PMID: 34561620 PMCID: PMC8563958 DOI: 10.1038/s41422-021-00569-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/31/2021] [Indexed: 02/07/2023] Open
Abstract
The melanocortin-4 receptor (MC4R), a hypothalamic master regulator of energy homeostasis and appetite, is a class A G-protein-coupled receptor and a prime target for the pharmacological treatment of obesity. Here, we present cryo-electron microscopy structures of MC4R–Gs-protein complexes with two drugs recently approved by the FDA, the peptide agonists NDP-α-MSH and setmelanotide, with 2.9 Å and 2.6 Å resolution. Together with signaling data from structure-derived MC4R mutants, the complex structures reveal the agonist-induced origin of transmembrane helix (TM) 6-regulated receptor activation. The ligand-binding modes of NDP-α-MSH, a high-affinity linear variant of the endogenous agonist α-MSH, and setmelanotide, a cyclic anti-obesity drug with biased signaling toward Gq/11, underline the key role of TM3 in ligand-specific interactions and of calcium ion as a ligand-adaptable cofactor. The agonist-specific TM3 interplay subsequently impacts receptor–Gs-protein interfaces at intracellular loop 2, which also regulates the G-protein coupling profile of this promiscuous receptor. Finally, our structures reveal mechanistic details of MC4R activation/inhibition, and provide important insights into the regulation of the receptor signaling profile which will facilitate the development of tailored anti-obesity drugs.
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22
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Pharmacological Characterization of Low Molecular Weight Biased Agonists at the Follicle Stimulating Hormone Receptor. Int J Mol Sci 2021; 22:ijms22189850. [PMID: 34576014 PMCID: PMC8469697 DOI: 10.3390/ijms22189850] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 01/14/2023] Open
Abstract
Follicle-stimulating hormone receptor (FSHR) plays a key role in reproduction through the activation of multiple signaling pathways. Low molecular weight (LMW) ligands composed of biased agonist properties are highly valuable tools to decipher complex signaling mechanisms as they allow selective activation of discrete signaling cascades. However, available LMW FSHR ligands have not been fully characterized yet. In this context, we explored the pharmacological diversity of three benzamide and two thiazolidinone derivatives compared to FSH. Concentration/activity curves were generated for Gαs, Gαq, Gαi, β-arrestin 2 recruitment, and cAMP production, using BRET assays in living cells. ERK phosphorylation was analyzed by Western blotting, and CRE-dependent transcription was assessed using a luciferase reporter assay. All assays were done in either wild-type, Gαs or β-arrestin 1/2 CRISPR knockout HEK293 cells. Bias factors were calculated for each pair of read-outs by using the operational model. Our results show that each ligand presented a discrete pharmacological efficacy compared to FSH, ranging from super-agonist for β-arrestin 2 recruitment to pure Gαs bias. Interestingly, LMW ligands generated kinetic profiles distinct from FSH (i.e., faster, slower or transient, depending on the ligand) and correlated with CRE-dependent transcription. In addition, clear system biases were observed in cells depleted of either Gαs or β-arrestin genes. Such LMW properties are useful pharmacological tools to better dissect the multiple signaling pathways activated by FSHR and assess their relative contributions at the cellular and physio-pathological levels.
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23
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Pereira PHS, Borges-Pereira L, Garcia CRS. Evidences of G Coupled-Protein Receptor (GPCR) Signaling in the human Malaria Parasite Plasmodium falciparum for Sensing its Microenvironment and the Role of Purinergic Signaling in Malaria Parasites. Curr Top Med Chem 2021; 21:171-180. [PMID: 32851963 DOI: 10.2174/1568026620666200826122716] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/15/2020] [Accepted: 07/20/2020] [Indexed: 11/22/2022]
Abstract
The nucleotides were discovered in the early 19th century and a few years later, the role of such molecules in energy metabolism and cell survival was postulated. In 1972, a pioneer work by Burnstock and colleagues suggested that ATP could also work as a neurotransmitter, which was known as the "purinergic hypothesis". The idea of ATP working as a signaling molecule faced initial resistance until the discovery of the receptors for ATP and other nucleotides, called purinergic receptors. Among the purinergic receptors, the P2Y family is of great importance because it comprises of G proteincoupled receptors (GPCRs). GPCRs are widespread among different organisms. These receptors work in the cells' ability to sense the external environment, which involves: to sense a dangerous situation or detect a pheromone through smell; the taste of food that should not be eaten; response to hormones that alter metabolism according to the body's need; or even transform light into an electrical stimulus to generate vision. Advances in understanding the mechanism of action of GPCRs shed light on increasingly promising treatments for diseases that have hitherto remained incurable, or the possibility of abolishing side effects from therapies widely used today.
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Affiliation(s)
- Pedro H S Pereira
- Department of Clinical and Toxicological Analyses, University of Sao Paulo, Sao Paulo, Brazil
| | - Lucas Borges-Pereira
- Department of Clinical and Toxicological Analyses, University of Sao Paulo, Sao Paulo, Brazil
| | - Célia R S Garcia
- Department of Clinical and Toxicological Analyses, University of Sao Paulo, Sao Paulo, Brazil
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24
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Glucose Metabolism in Burns-What Happens? Int J Mol Sci 2021; 22:ijms22105159. [PMID: 34068151 PMCID: PMC8153015 DOI: 10.3390/ijms22105159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 11/16/2022] Open
Abstract
Severe burns represent an important challenge for patients and medical teams. They lead to profound metabolic alterations, trigger a systemic inflammatory response, crush the immune defense, impair the function of the heart, lungs, kidneys, liver, etc. The metabolism is shifted towards a hypermetabolic state, and this situation might persist for years after the burn, having deleterious consequences for the patient's health. Severely burned patients lack energy substrates and react in order to produce and maintain augmented levels of glucose, which is the fuel "ready to use" by cells. In this paper, we discuss biological substances that induce a hyperglycemic response, concur to insulin resistance, and determine cell disturbance after a severe burn. We also focus on the most effective agents that provide pharmacological modulations of the changes in glucose metabolism.
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Hudzik TJ, Patel M, Brown A. β 2 -Adrenoceptor agonist activity of higenamine. Drug Test Anal 2021; 13:261-267. [PMID: 33369180 PMCID: PMC7898339 DOI: 10.1002/dta.2992] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/24/2020] [Accepted: 12/04/2020] [Indexed: 12/29/2022]
Abstract
Higenamine was included in the World Anti-Doping Agency (WADA) Prohibited Substances and Methods List as a β2 -adrenoceptor agonist in 2017, thereby resulting in its prohibition both in and out of competition. The present mini review describes the physiology and pharmacology of adrenoceptors, summarizes the literature addressing the mechanism of action of higenamine and extends these findings with previously unpublished in silico and in vitro work. Studies conducted in isolated in vitro systems, whole-animal preparations and a small number of clinical studies suggest that higenamine acts in part as a β2 -adrenoceptor agonist. In silico predictive tools indicated that higenamine and possibly a metabolite have a high probability of interacting with the β2 -receptor as an agonist. Stable expression of human β2 -receptors in Chinese hamster ovary (CHO) cells to measure agonist activity not only confirmed the activity of higenamine at β2 but also closely agreed with the in silico prediction of potency for this compound. These data confirm and extend literature findings supporting the inclusion of higenamine in the Prohibited List.
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Affiliation(s)
- Thomas J. Hudzik
- Department of ResearchGlaxoSmithKline1250 S. Collegeville RdCollegevillePA1926USA
| | - Metul Patel
- Department of ResearchGlaxoSmithKlineGunnels Wood RdStevenageSG1 2NYUK
| | - Andrew Brown
- Department of ResearchGlaxoSmithKlineGunnels Wood RdStevenageSG1 2NYUK
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Xu D, Xie L, Zhang Z, Wang D, Qiu J, Yu W, Xu C, He C, Xu X, Yin J. Preliminary Investigation about the Expression of G Protein-Coupled Receptors in Platelets from Patients with Chronic Immune Thrombocytopenic Purpura. Acta Haematol 2021; 144:551-559. [PMID: 33849009 DOI: 10.1159/000514907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 02/02/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The objective of this study was to determine the expression of G protein-coupled receptors (GPCRs) in platelets from adult patients with chronic immune thrombocytopenic purpura (ITP). METHODS Peripheral blood samples were collected from 40 patients with chronic ITP in the Second Affiliated Hospital of Shantou University Medical College, and 40 peripheral blood samples from healthy volunteers were collected; expressions of the adenosine diphosphate receptors (P2Y1 and P2Y12), alpha-2A adrenergic receptor (α2A-AR), and thromboxane A2 receptor (TP) in platelets were detected by flow cytometry. Gα protein, protease-activated receptor 1 (PAR1), and protease-activated receptor 4 (PAR4) were analyzed by Western blot and analyzed statistically. RESULTS Flow cytometry measurements of mean fluorescence intensities showed platelets from patients with chronic ITP, compared to healthy individuals, had significantly higher levels of P2Y1 (31.4 ± 2.2 vs. 7.8 ± 0.8), P2Y12 (29.6 ± 2.1 vs. 7.2 ± 1.3), α2A-AR (25.8 ± 2.9 vs. 9.8 ± 0.9), and TP (39.8 ± 3.1 vs. 4.7 ± 0.6) (all p < 0.01). Similarly, integrated optical density analysis of Western blots showed that platelets from patients with chronic ITP had significantly higher levels of Gα (1046.3 ± 159.96 vs. 254.49 ± 39.51), PAR1 (832.98 ± 98.81 vs. 203.92 ± 27.47), and PAR4 (1518.80 ± 272.45 vs. 431.27 ± 41.86) (all p < 0.01). CONCLUSION Expression of GPCRs is increased in platelets from patients with chronic ITP, suggesting that platelets of chronic ITP may participate in the complicated biological process by means of GPCR-mediated signaling pathways.
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Affiliation(s)
- Daming Xu
- Division of Urological Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Long Xie
- Department of Clinical Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Zewen Zhang
- Division of Hematology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Duanxu Wang
- Office of Medical Affairs Administration, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Jinfeng Qiu
- Division of Respirology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Wenjun Yu
- Division of Hematology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Chengwei Xu
- Department of Hemodialysis, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Chunling He
- Department of Pathology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Xianru Xu
- Division of Inventional Ultrasonic Therapeutics, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Jun Yin
- Department of Clinical Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
- Division of Hematology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
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Xing G, Woo AYH, Pan L, Lin B, Cheng MS. Recent Advances in β 2-Agonists for Treatment of Chronic Respiratory Diseases and Heart Failure. J Med Chem 2020; 63:15218-15242. [PMID: 33213146 DOI: 10.1021/acs.jmedchem.0c01195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
β2-Adrenoceptor (β2-AR) agonists are widely used as bronchodilators. The emerge of ultralong acting β2-agonists is an important breakthrough in pulmonary medicine. In this review, we will provide mechanistic insights into the application of β2-agonists in asthma, chronic obstructive pulmonary disease (COPD), and heart failure (HF). Recent studies in β-AR signal transduction have revealed opposing functions of the β1-AR and the β2-AR on cardiomyocyte survival. Thus, β2-agonists and β-blockers in combination may represent a novel strategy for HF management. Allosteric modulation and biased agonism at the β2-AR also provide a theoretical basis for developing drugs with novel mechanisms of action and pharmacological profiles. Overlap of COPD and HF presents a substantial clinical challenge but also a unique opportunity for evaluation of the cardiovascular safety of β2-agonists. Further basic and clinical research along these lines can help us develop better drugs and innovative strategies for the management of these difficult-to-treat diseases.
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Affiliation(s)
- Gang Xing
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Anthony Yiu-Ho Woo
- Department of Pharmacology, School of Life Sciences and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Li Pan
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Bin Lin
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Mao-Sheng Cheng
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang 110016, China.,Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
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Gupte TM, Ritt M, Sivaramakrishnan S. ER/K-link-Leveraging a native protein linker to probe dynamic cellular interactions. Methods Enzymol 2020; 647:173-208. [PMID: 33482988 PMCID: PMC8009693 DOI: 10.1016/bs.mie.2020.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ER/K α-helices are a subset of single alpha helical domains, which exhibit unusual stability as isolated protein secondary structures. They adopt an elongated structural conformation, while regulating the frequency of interactions between proteins or polypeptides fused to their ends. Here we review recent advances on the structure, stability and function of ER/K α-helices as linkers (ER/K linkers) in native proteins. We describe methodological considerations in the molecular cloning, protein expression and measurement of interaction strengths, using sensors incorporating ER/K linkers. We highlight biological insights obtained over the last decade by leveraging distinct biophysical features of ER/K-linked sensors. We conclude with the outlook for the use of ER/K linkers in the selective modulation of dynamic cellular interactions.
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Affiliation(s)
- Tejas M Gupte
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States.
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Protein-ligand binding with the coarse-grained Martini model. Nat Commun 2020; 11:3714. [PMID: 32709852 PMCID: PMC7382508 DOI: 10.1038/s41467-020-17437-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 06/29/2020] [Indexed: 02/06/2023] Open
Abstract
The detailed understanding of the binding of small molecules to proteins is the key for the development of novel drugs or to increase the acceptance of substrates by enzymes. Nowadays, computer-aided design of protein–ligand binding is an important tool to accomplish this task. Current approaches typically rely on high-throughput docking essays or computationally expensive atomistic molecular dynamics simulations. Here, we present an approach to use the recently re-parametrized coarse-grained Martini model to perform unbiased millisecond sampling of protein–ligand interactions of small drug-like molecules. Remarkably, we achieve high accuracy without the need of any a priori knowledge of binding pockets or pathways. Our approach is applied to a range of systems from the well-characterized T4 lysozyme over members of the GPCR family and nuclear receptors to a variety of enzymes. The presented results open the way to high-throughput screening of ligand libraries or protein mutations using the coarse-grained Martini model. Computer-aided design of protein-ligand binding is important for the development of novel drugs. Here authors present an approach to use the recently re-parametrized coarse-grained Martini model to perform unbiased millisecond sampling of protein-ligand binding interactions of small drug-like molecules.
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Casarini L, Crépieux P, Reiter E, Lazzaretti C, Paradiso E, Rochira V, Brigante G, Santi D, Simoni M. FSH for the Treatment of Male Infertility. Int J Mol Sci 2020; 21:ijms21072270. [PMID: 32218314 PMCID: PMC7177393 DOI: 10.3390/ijms21072270] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/22/2020] [Accepted: 03/24/2020] [Indexed: 12/11/2022] Open
Abstract
Follicle-stimulating hormone (FSH) supports spermatogenesis acting via its receptor (FSHR), which activates trophic effects in gonadal Sertoli cells. These pathways are targeted by hormonal drugs used for clinical treatment of infertile men, mainly belonging to sub-groups defined as hypogonadotropic hypogonadism or idiopathic infertility. While, in the first case, fertility may be efficiently restored by specific treatments, such as pulsatile gonadotropin releasing hormone (GnRH) or choriogonadotropin (hCG) alone or in combination with FSH, less is known about the efficacy of FSH in supporting the treatment of male idiopathic infertility. This review focuses on the role of FSH in the clinical approach to male reproduction, addressing the state-of-the-art from the little data available and discussing the pharmacological evidence. New compounds, such as allosteric ligands, dually active, chimeric gonadotropins and immunoglobulins, may represent interesting avenues for future personalized, pharmacological approaches to male infertility.
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Affiliation(s)
- Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- Center for Genomic Research, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
- Correspondence: ; Tel.: +39-0593961705; Fax: +39-0593962018
| | - Pascale Crépieux
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Institut Français du Cheval et de l’Equitation (IFCE), Université de Tours, 37380 Nouzilly, France; (P.C.); (E.R.)
| | - Eric Reiter
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Institut Français du Cheval et de l’Equitation (IFCE), Université de Tours, 37380 Nouzilly, France; (P.C.); (E.R.)
| | - Clara Lazzaretti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- International PhD School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
| | - Elia Paradiso
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- International PhD School in Clinical and Experimental Medicine (CEM), University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
| | - Vincenzo Rochira
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Via P. Giardini 1355, 41126 Modena, Italy
| | - Giulia Brigante
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Via P. Giardini 1355, 41126 Modena, Italy
| | - Daniele Santi
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Via P. Giardini 1355, 41126 Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini 1355, 41126 Modena, Italy; (C.L.); (E.P.); (V.R.); (G.B.); (D.S.); (M.S.)
- Center for Genomic Research, University of Modena and Reggio Emilia, Via G. Campi 287, 41125 Modena, Italy
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Institut Français du Cheval et de l’Equitation (IFCE), Université de Tours, 37380 Nouzilly, France; (P.C.); (E.R.)
- Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Via P. Giardini 1355, 41126 Modena, Italy
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AGAP2: Modulating TGFβ1-Signaling in the Regulation of Liver Fibrosis. Int J Mol Sci 2020; 21:ijms21041400. [PMID: 32092977 PMCID: PMC7073092 DOI: 10.3390/ijms21041400] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/16/2020] [Accepted: 02/17/2020] [Indexed: 12/22/2022] Open
Abstract
AGAP2 (Arf GAP with GTP-binding protein-like domain, Ankyrin repeat and PH domain 2) isoform 2 is a protein that belongs to the Arf GAP (GTPase activating protein) protein family. These proteins act as GTPase switches for Arfs, which are Ras superfamily members, being therefore involved in signaling regulation. Arf GAP proteins have been shown to participate in several cellular functions including membrane trafficking and actin cytoskeleton remodeling. AGAP2 is a multi-tasking Arf GAP that also presents GTPase activity and is involved in several signaling pathways related with apoptosis, cell survival, migration, and receptor trafficking. The increase of AGAP2 levels is associated with pathologies as cancer and fibrosis. Transforming growth factor beta-1 (TGF-β1) is the most potent pro-fibrotic cytokine identified to date, currently accepted as the principal mediator of the fibrotic response in liver, lung, and kidney. Recent literature has described that the expression of AGAP2 modulates some of the pro-fibrotic effects described for TGF-β1 in the liver. The present review is focused on the interrelated molecular effects between AGAP2 and TGFβ1 expression, presenting AGAP2 as a new player in the signaling of this pro-fibrotic cytokine, thereby contributing to the progression of hepatic fibrosis.
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Lamichhane R, Liu JJ, White KL, Katritch V, Stevens RC, Wüthrich K, Millar DP. Biased Signaling of the G-Protein-Coupled Receptor β 2AR Is Governed by Conformational Exchange Kinetics. Structure 2020; 28:371-377.e3. [PMID: 31978323 DOI: 10.1016/j.str.2020.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/11/2019] [Accepted: 01/03/2020] [Indexed: 01/14/2023]
Abstract
G-protein-coupled receptors (GPCRs) mediate a wide range of human physiological functions by transducing extracellular ligand binding events into intracellular responses. GPCRs can activate parallel, independent signaling pathways mediated by G proteins or β-arrestins. Whereas "balanced" agonists activate both pathways equally, "biased" agonists dominantly activate one pathway, which is of interest for designing GPCR-targeting drugs because it may mitigate undesirable side effects. Previous studies demonstrated that β-arrestin activation is associated with transmembrane helix VII (TM VII) of GPCRs. Here, single-molecule fluorescence spectroscopy with the β2-adrenergic receptor (β2AR) in the ligand-free state showed that TM VII spontaneously fluctuates between one inactive and one active-like conformation. The presence of the β-arrestin-biased agonist isoetharine prolongs the dwell time of TM VII in the active-like conformation compared with the balanced agonist formoterol, suggesting that ligands can induce signaling bias by modulating the kinetics of receptor conformational exchange.
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Affiliation(s)
- Rajan Lamichhane
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jeffrey J Liu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Kate L White
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Childs Way, MC3502, Los Angeles, CA 90089, USA
| | - Vsevolod Katritch
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Childs Way, MC3502, Los Angeles, CA 90089, USA
| | - Raymond C Stevens
- Departments of Biological Sciences and Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Childs Way, MC3502, Los Angeles, CA 90089, USA
| | - Kurt Wüthrich
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - David P Millar
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Klepac K, Yang J, Hildebrand S, Pfeifer A. RGS2: A multifunctional signaling hub that balances brown adipose tissue function and differentiation. Mol Metab 2019; 30:173-183. [PMID: 31767169 PMCID: PMC6807268 DOI: 10.1016/j.molmet.2019.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/12/2019] [Accepted: 09/28/2019] [Indexed: 12/28/2022] Open
Abstract
Objective Recruitment of brown adipose tissue (BAT) is a potential new strategy for increasing energy expenditure (EE) to treat obesity. G protein–coupled receptors (GPCRs) represent promising targets to activate BAT, as they are the major regulators of BAT biological function. To identify new regulators of GPCR signaling in BAT, we studied the role of Regulator of G protein Signaling 2 (RGS2) in brown adipocytes and BAT. Methods We combined pharmacological and genetic tools to investigate the role of RGS2 in BAT in vitro and in vivo. Adipocyte progenitors were isolated from wild-type (WT) and RGS2 knockout (RGS2−/−) BAT and differentiated to brown adipocytes. This approach was complemented with knockdown of RGS2 using lentiviral shRNAs (shRGS2). Adipogenesis was analyzed by Oil Red O staining and by determining the expression of adipogenic and thermogenic markers. Pharmacological modulators and fluorescence staining of F-acting stress fibers were employed to identify the underlying signaling pathways. In vivo, the activity of BAT was assessed by ex vivo lipolysis and by measuring whole-body EE by indirect calorimetry in metabolic cages. Results RGS2 is highly expressed in BAT, and treatment with cGMP—an important enhancer of brown adipocyte differentiation—further increased RGS2 expression. Loss of RGS2 strongly suppressed adipogenesis and the expression of thermogenic genes in brown adipocytes. Mechanistically, we found increased Gq/Rho/Rho kinase (ROCK) signaling in the absence of RGS2. Surprisingly, in vivo analysis revealed elevated BAT activity in RGS2-deficient mice that was caused by enhanced Gs/cAMP signaling. Conclusion Overall, RGS2 regulates two major signaling pathways in BAT: Gq and Gs. On the one hand, RGS2 promotes brown adipogenesis by counteracting the inhibitory action of Gq/Rho/ROCK signaling. On the other hand, RGS2 decreases the activity of BAT through the inhibition of Gs signaling and cAMP production. Thus, RGS2 might represent a stress modulator that protects BAT from overstimulation. RGS2 regulates brown adipose tissue (BAT) by inhibiting two major G protein-coupled receptor (GPCR) pathways – Gq and Gs. Deletion of RGS2 impairs the differentiation of murine brown adipocytes due to elevated Gq/Rho/ROCK signaling. In vivo, RGS2 knock-out mice show an increase in BAT lipolysis and whole-body energy expenditure.
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Affiliation(s)
- Katarina Klepac
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany; Research Training Group 1873, University of Bonn, 53127 Bonn, Germany.
| | - JuHee Yang
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany; Research Training Group 1873, University of Bonn, 53127 Bonn, Germany
| | - Staffan Hildebrand
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, 53127 Bonn, Germany; Research Training Group 1873, University of Bonn, 53127 Bonn, Germany; PharmaCenter, University of Bonn, 53127 Bonn, Germany.
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Mitochondrial-Derived Peptide MOTS-c Increases Adipose Thermogenic Activation to Promote Cold Adaptation. Int J Mol Sci 2019; 20:ijms20102456. [PMID: 31109005 PMCID: PMC6567243 DOI: 10.3390/ijms20102456] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 05/09/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023] Open
Abstract
Cold exposure stress causes hypothermia, cognitive impairment, liver injury, and cardiovascular diseases, thereby increasing morbidity and mortality. Paradoxically, cold acclimation is believed to confer metabolic improvement to allow individuals to adapt to cold, harsh conditions and to protect them from cold stress-induced diseases. However, the therapeutic strategy to enhance cold acclimation remains less studied. Here, we demonstrate that the mitochondrial-derived peptide MOTS-c efficiently promotes cold adaptation. Following cold exposure, the improvement of adipose non-shivering thermogenesis facilitated cold adaptation. MOTS-c, a newly identified peptide, is secreted by mitochondria. In this study, we observed that the level of MOTS-c in serum decreased after cold stress. MOTS-c treatment enhanced cold tolerance and reduced lipid trafficking to the liver. In addition, MOTS-c dramatically upregulated brown adipose tissue (BAT) thermogenic gene expression and increased white fat “browning”. This effect might have been mediated by MOTS-c-activated phosphorylation of the ERK signaling pathway. The inhibition of ERK signaling disturbed the up-regulatory effect of MOTS-c on thermogenesis. In summary, our results indicate that MOTS-c treatment is a potential therapeutic strategy for defending against cold stress by increasing the adipose thermogenesis via the ERK pathway.
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Banister SD, Krishna Kumar K, Kumar V, Kobilka BK, Malhotra SV. Selective modulation of the cannabinoid type 1 (CB 1) receptor as an emerging platform for the treatment of neuropathic pain. MEDCHEMCOMM 2019; 10:647-659. [PMID: 31191856 PMCID: PMC6533890 DOI: 10.1039/c8md00595h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/12/2019] [Indexed: 12/27/2022]
Abstract
Neuropathic pain is caused by a lesion or dysfunction in the nervous system, and it may arise from illness, be drug-induced or caused by toxin exposure. Since the discovery of two G-protein-coupled cannabinoid receptors (CB1 and CB2) nearly three decades ago, there has been a rapid expansion in our understanding of cannabinoid pharmacology. This is currently one of the most active fields of neuropharmacology, and interest has emerged in developing cannabinoids and other small molecule modulators of CB1 and CB2 as therapeutics for neuropathic pain. This short review article provides an overview of the chemotypes currently under investigation for the development of novel neuropathic pain treatments targeting CB1 receptors.
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Affiliation(s)
- Samuel D Banister
- Department of Radiation Oncology , Stanford University School of Medicine , Stanford , CA 94305 , USA .
| | - Kaavya Krishna Kumar
- Department of Molecular and Cellular Physiology , Stanford University School of Medicine , Stanford , CA 94305 , USA
| | - Vineet Kumar
- Department of Radiation Oncology , Stanford University School of Medicine , Stanford , CA 94305 , USA .
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology , Stanford University School of Medicine , Stanford , CA 94305 , USA
| | - Sanjay V Malhotra
- Department of Radiation Oncology , Stanford University School of Medicine , Stanford , CA 94305 , USA .
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Ma C, Gao T, Ju J, Zhang Y, Ni Q, Li Y, Zhao Z, Chai J, Yang X, Sun M. Sympathetic innervation contributes to perineural invasion of salivary adenoid cystic carcinoma via the β2-adrenergic receptor. Onco Targets Ther 2019; 12:1475-1495. [PMID: 30863115 PMCID: PMC6391132 DOI: 10.2147/ott.s190847] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose Perineural invasion (PNI) is reported to correlate with local recurrence and poor prognosis of salivary adenoid cystic carcinoma (SACC). However, the pathogenesis of PNI remains unclear. The aims of this study were to investigate the correlation between sympathetic innervation and SACC PNI and to elucidate how the sympathetic neurotransmitter norepinephrine (NE) regulates the PNI process. Materials and methods Sympathetic innervation and β2-adrenergic receptor (β2-AR) expression in SACC tissues were evaluated by immunohistochemistry. The NE concentrations in SACC tissues and dorsal root ganglia (DRG) coculture models were measured by ELISA. β2-AR expression in SACC cells was detected by performing quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence assay. SACC cells were treated with NE, the nonselective α-AR blocker phentolamine, the β2-AR antagonist ICI118,551, or were transfected with β2-AR small interfering RNA (siRNA). Proliferation was evaluated in methyl thiazolyl tetrazolium assay, and migration was evaluated in Transwell assay and wound-healing assay. PNI was tested through both Transwell assay and a DRG coculture model. The expressions of epithelial–mesenchymal transition (EMT) markers and matrix metalloproteinases (MMPs) were measured by performing qRT-PCR and Western blot assay. Results Sympathetic innervation and β2-AR were highly distributed in SACC tissues and correlated positively with PNI (P=0.035 and P=0.003, respectively). The sympathetic neurotransmitter NE was overexpressed in SACC tissues and DRG coculture models. Exogenously added NE promoted proliferation, migration, and PNI of SACC cells via β2-AR activation. NE/β2-AR signaling may promote proliferation, migration, and PNI by inducing EMT and upregulating MMPs. However, β2-AR inhibition with either an antagonist or siRNA abrogated NE-induced PNI. Conclusion Collectively, our findings reveal the supportive role of sympathetic innervation in the pathogenesis of SACC PNI and suggest β2-AR as a potential therapeutic target for treating PNI in SACC.
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Affiliation(s)
- Chao Ma
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China,
| | - Tao Gao
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China, .,Department of Stomatology, The First Hospital of Yu Lin, Yu Lin, Shaanxi, China
| | - Jun Ju
- Department of Otolaryngology Head and Neck Surgery, Navy General Hospital, Beijing, China
| | - Yi Zhang
- Department of Geriatrics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Qianwei Ni
- Department of Oral and Maxillofacial Surgery, General Hospital of Xinjiang Military Region, Urumqi, Xin Jiang, China
| | - Yun Li
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China,
| | - Zhenyan Zhao
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China,
| | - Juan Chai
- Department of Oral and Maxillofacial Surgery, School of Stomatology, Xi'an Medical University, Xi'an, Shaanxi, China
| | - Xiangming Yang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China,
| | - Moyi Sun
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, China,
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Schnabl K, Westermeier J, Li Y, Klingenspor M. Opposing Actions of Adrenocorticotropic Hormone and Glucocorticoids on UCP1-Mediated Respiration in Brown Adipocytes. Front Physiol 2019; 9:1931. [PMID: 30705635 PMCID: PMC6344423 DOI: 10.3389/fphys.2018.01931] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/21/2018] [Indexed: 12/23/2022] Open
Abstract
Brown fat is a potential target in the treatment of metabolic disorders as recruitment and activation of this thermogenic organ increases energy expenditure and promotes satiation. A large variety of G-protein coupled receptors, known as classical drug targets in pharmacotherapy, is expressed in brown adipocytes. In the present study, we analyzed transcriptome data for the expression of these receptors to identify potential pathways for the recruitment and activation of thermogenic capacity in brown fat. Our analysis revealed 12 Gs-coupled receptors abundantly expressed in murine brown fat. We screened ligands for these receptors in brown adipocytes for their ability to stimulate UCP1-mediated respiration and Ucp1 gene expression. Adrenocorticotropic hormone (ACTH), a ligand for the melanocortin 2 receptor (MC2R), turned out to be the most potent activator of UCP1 whereas its capability to stimulate Ucp1 gene expression was comparably low. Adrenocorticotropic hormone is the glandotropic hormone of the endocrine hypothalamus–pituitary–adrenal-axis stimulating the release of glucocorticoids in response to stress. In primary brown adipocytes ACTH acutely increased the cellular respiration rate similar to isoproterenol, a β-adrenergic receptor agonist. The effect of ACTH on brown adipocyte respiration was mediated via the MC2R as confirmed by using an antagonist. Inhibitor-based studies revealed that ACTH-induced respiration was dependent on protein kinase A and lipolysis, compatible with a rise of intracellular cAMP in response to ACTH. Furthermore, it is dependent on UCP1, as cells from UCP1-knockout mice did not respond. Taken together, ACTH is a non-adrenergic activator of murine brown adipocytes, initiating the canonical adenylyl cyclase–cAMP–protein kinase A-lipolysis-UCP1 pathway, and thus a potential target for the recruitment and activation of thermogenic capacity. Based on these findings in primary cell culture, the physiological significance might be that cold-induced ACTH in concert with norepinephrine released from sympathetic nerves contributes to BAT thermogenesis. Notably, dexamethasone attenuated isoproterenol-induced respiration. This effect increased gradually with the duration of pretreatment. In vivo, glucocorticoid release triggered by ACTH might oppose beta-adrenergic stimulation of metabolic fuel combustion in BAT and limit stress-induced hyperthermia.
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Affiliation(s)
- Katharina Schnabl
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Julia Westermeier
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Yongguo Li
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Martin Klingenspor
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
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Abstract
Ubiquitination of G protein-coupled receptors (GPCRs) is an important dynamic posttranslational modification that has been linked to the intracellular trafficking of internalized GPCRs to lysosomes. Ubiquitination of GPCRs is mediated by specific E3 ubiquitin ligases that are scaffolded by the adaptor proteins called β-arrestins. Traditionally, detection of GPCR ubiquitination is achieved by using ubiquitin antibodies to Western blot immunoprecipitates of detergent-solubilized GPCRs expressed in heterologous cells. However, studies have also shown that bioluminescence resonance energy transfer (BRET)-based techniques can reveal ubiquitination of GPCRs in intact cells and in real time. This chapter describes a step-by-step protocol to evaluate ubiquitination of GPCRs using the BRET methodology.
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Choi M, Staus DP, Wingler LM, Ahn S, Pani B, Capel WD, Lefkowitz RJ. G protein-coupled receptor kinases (GRKs) orchestrate biased agonism at the β 2-adrenergic receptor. Sci Signal 2018; 11:11/544/eaar7084. [PMID: 30131371 DOI: 10.1126/scisignal.aar7084] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Biased agonists of G protein-coupled receptors (GPCRs), which selectively activate either G protein- or β-arrestin-mediated signaling pathways, are of major therapeutic interest because they have the potential to show improved efficacy and specificity as drugs. Efforts to understand the mechanistic basis of this phenomenon have focused on the hypothesis that G proteins and β-arrestins preferentially couple to distinct GPCR conformations. However, because GPCR kinase (GRK)-dependent receptor phosphorylation is a critical prerequisite for the recruitment of β-arrestins to most GPCRs, GRKs themselves may play an important role in establishing biased signaling. We showed that an alanine mutant of the highly conserved residue tyrosine 219 (Y219A) in transmembrane domain five of the β2-adrenergic receptor (β2AR) was incapable of β-arrestin recruitment, receptor internalization, and β-arrestin-mediated activation of extracellular signal-regulated kinase (ERK), whereas it retained the ability to signal through G protein. We found that the impaired β-arrestin recruitment in cells was due to reduced GRK-mediated phosphorylation of the β2AR Y219A C terminus, which was recapitulated in vitro with purified components. Furthermore, in vitro ligation of a synthetically phosphorylated peptide onto the C terminus of β2AR Y219A rescued both the initial recruitment of β-arrestin and its engagement with the intracellular core of the receptor. These data suggest that the Y219A mutation generates a G protein-biased state primarily by conformational selection against GRK coupling, rather than against β-arrestin. Together, these findings highlight the importance of GRKs in modulating the biased agonism of GPCRs.
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Affiliation(s)
- Minjung Choi
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Dean P Staus
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA. .,Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Laura M Wingler
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Seungkirl Ahn
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Biswaranjan Pani
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - William D Capel
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Robert J Lefkowitz
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA. .,Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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Ulloa-Aguirre A, Reiter E, Crépieux P. FSH Receptor Signaling: Complexity of Interactions and Signal Diversity. Endocrinology 2018; 159:3020-3035. [PMID: 29982321 DOI: 10.1210/en.2018-00452] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022]
Abstract
FSH is synthesized in the pituitary by gonadotrope cells. By binding to and interacting with its cognate receptor [FSH receptor (FSHR)] in the gonads, this gonadotropin plays a key role in the control of gonadal function and reproduction. Upon activation, the FSHR undergoes conformational changes leading to transduction of intracellular signals, including dissociation of G protein complexes into components and activation of several associated interacting partners, which concertedly regulate downstream effectors. The canonical Gs/cAMP/protein kinase A pathway, considered for a long time as the sole effector of FSHR-mediated signaling, is now viewed as one of several mechanisms employed by this receptor to transduce intracellular signals in response to the FSH stimulus. This complex network of signaling pathways allows for a fine-tuning regulation of the gonadotropic stimulus, where activation/inhibition of its multiple components vary depending on the cell context, cell developmental stage, and concentration of associated receptors and corresponding ligands. Activation of these multiple signaling modules eventually converge to the hormone-integrated biological response, including survival, proliferation and differentiation of target cells, synthesis and secretion of paracrine/autocrine regulators, and, at the molecular level, functional selectivity and differential gene expression. In this mini-review, we discuss the complexity of FSHR-mediated intracellular signals activated in response to ligand stimulation. A better understanding of the signaling pathways involved in FSH action might potentially influence the development of new therapeutic strategies for reproductive disorders.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eric Reiter
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
| | - Pascale Crépieux
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
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The role of catecholamines in HIV neuropathogenesis. Brain Res 2018; 1702:54-73. [PMID: 29705605 DOI: 10.1016/j.brainres.2018.04.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/21/2022]
Abstract
The success of anti-retroviral therapy has improved the quality of life and lifespan of HIV + individuals, transforming HIV infection into a chronic condition. These improvements have come with a cost, as chronic HIV infection and long-term therapy have resulted in the emergence of a number of new pathologies. This includes a variety of the neuropathological and neurocognitive effects collectively known as HIVassociated neurocognitive disorders (HAND) or NeuroHIV. These effects persist even in the absence of viral replication, suggesting that they are mediated the long-term changes in the CNS induced by HIV infection rather than by active replication. Among these effects are significant changes in catecholaminergic neurotransmission, especially in dopaminergic brain regions. In HIV-infected individuals not treated with ARV show prominent neuropathology is common in dopamine-rich brain regions and altered autonomic nervous system activity. Even infected individuals on therapy, there is significant dopaminergic neuropathology, and elevated stress and norepinephrine levels correlate with a decreased effectiveness of antiretroviral drugs. As catecholamines function as immunomodulatory factors, the resultant dysregulation of catecholaminergic tone could substantially alter the development of HIVassociated neuroinflammation and neuropathology. In this review, we discuss the role of catecholamines in the etiology of HIV neuropathogenesis. Providing a comprehensive examination of what is known about these molecules in the context of HIV-associated disease demonstrates the importance of further studies in this area, and may open the door to new therapeutic strategies that specifically ameliorate the effects of catecholaminergic dysregulation on NeuroHIV.
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43
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Wang W, Qiao Y, Li Z. New Insights into Modes of GPCR Activation. Trends Pharmacol Sci 2018; 39:367-386. [DOI: 10.1016/j.tips.2018.01.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/03/2018] [Accepted: 01/08/2018] [Indexed: 12/22/2022]
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44
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Wang G, Wei Z, Wu G. Role of Rab GTPases in the export trafficking of G protein-coupled receptors. Small GTPases 2018; 9:130-135. [PMID: 28125329 PMCID: PMC5902197 DOI: 10.1080/21541248.2016.1277000] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute a superfamily of cell surface receptors that regulate a variety of cell functions. As the cell surface is the functional destination for most GPCRs, the cell surface targeting process represents a crucial checkpoint in controlling the functionality of the receptors. However, the molecular mechanisms underlying the cell surface delivery of newly synthesized GPCRs remain poorly understood. In this review, we will highlight the role of Rab GTPases in GPCR cell surface transport, particularly post-Golgi traffic, and discuss the underlying molecular mechanisms.
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Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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45
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Follicle-Stimulating Hormone Receptor: Advances and Remaining Challenges. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:1-58. [DOI: 10.1016/bs.ircmb.2018.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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46
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Wolf S, Jovancevic N, Gelis L, Pietsch S, Hatt H, Gerwert K. Dynamical Binding Modes Determine Agonistic and Antagonistic Ligand Effects in the Prostate-Specific G-Protein Coupled Receptor (PSGR). Sci Rep 2017; 7:16007. [PMID: 29167480 PMCID: PMC5700038 DOI: 10.1038/s41598-017-16001-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 11/03/2017] [Indexed: 01/14/2023] Open
Abstract
We analysed the ligand-based activation mechanism of the prostate-specific G-protein coupled receptor (PSGR), which is an olfactory receptor that mediates cellular growth in prostate cancer cells. Furthermore, it is an olfactory receptor with a known chemically near identic antagonist/agonist pair, α- and β-ionone. Using a combined theoretical and experimental approach, we propose that this receptor is activated by a ligand-induced rearrangement of a protein-internal hydrogen bond network. Surprisingly, this rearrangement is not induced by interaction of the ligand with the network, but by dynamic van der Waals contacts of the ligand with the involved amino acid side chains, altering their conformations and intraprotein connectivity. Ligand recognition in this GPCR is therefore highly stereo selective, but seemingly lacks any ligand recognition via polar contacts. A putative olfactory receptor-based drug design scheme will have to take this unique mode of protein/ligand action into account.
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Affiliation(s)
- Steffen Wolf
- Department of Biophysics, ND 04 North, Ruhr-University Bochum, 44780, Bochum, Germany.
- Department of Biophysics, CAS-MPG Partner Institute for Computational Biology, Key Laboratory of Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, P.R. China.
| | - Nikolina Jovancevic
- Department of Cellphysiology, ND 4, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Lian Gelis
- Department of Cellphysiology, ND 4, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Sebastian Pietsch
- Department of Biophysics, ND 04 North, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Hanns Hatt
- Department of Cellphysiology, ND 4, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Klaus Gerwert
- Department of Biophysics, ND 04 North, Ruhr-University Bochum, 44780, Bochum, Germany
- Department of Biophysics, CAS-MPG Partner Institute for Computational Biology, Key Laboratory of Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, P.R. China
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Geithe C, Protze J, Kreuchwig F, Krause G, Krautwurst D. Structural determinants of a conserved enantiomer-selective carvone binding pocket in the human odorant receptor OR1A1. Cell Mol Life Sci 2017; 74:4209-4229. [PMID: 28656349 PMCID: PMC11107518 DOI: 10.1007/s00018-017-2576-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/29/2017] [Accepted: 06/16/2017] [Indexed: 12/17/2022]
Abstract
Chirality is a common phenomenon within odorants. Most pairs of enantiomers show only moderate differences in odor quality. One example for enantiomers that are easily discriminated by their odor quality is the carvones: humans significantly distinguish between the spearmint-like (R)-(-)-carvone and caraway-like (S)-(+)-carvone enantiomers. Moreover, for the (R)-(-)-carvone, an anosmia is observed in about 8% of the population, suggesting enantioselective odorant receptors (ORs). With only about 15% de-orphaned human ORs, the lack of OR crystal structures, and few comprehensive studies combining in silico and experimental approaches to elucidate structure-function relations of ORs, knowledge on cognate odorant/OR interactions is still sparse. An adjusted homology modeling approach considering OR-specific proline-caused conformations, odorant docking studies, single-nucleotide polymorphism (SNP) analysis, site-directed mutagenesis, and subsequent functional studies with recombinant ORs in a cell-based, real-time luminescence assay revealed 11 amino acid positions to constitute an enantioselective binding pocket necessary for a carvone function in human OR1A1 and murine Olfr43, respectively. Here, we identified enantioselective molecular determinants in both ORs that discriminate between minty and caraway odor. Comparison with orthologs from 36 mammalian species demonstrated a hominid-specific carvone binding pocket with about 100% conservation. Moreover, we identified loss-of-function SNPs associated with the carvone binding pocket of OR1A1. Given carvone enantiomer-specific receptor activation patterns including OR1A1, our data suggest OR1A1 as a candidate receptor for constituting a carvone enantioselective phenotype, which may help to explain mechanisms underlying a (R)-(-)-carvone-specific anosmia in humans.
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Affiliation(s)
- Christiane Geithe
- Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institut (DFA), Freising, Germany
| | - Jonas Protze
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Franziska Kreuchwig
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Gerd Krause
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
| | - Dietmar Krautwurst
- Deutsche Forschungsanstalt für Lebensmittelchemie Leibniz Institut (DFA), Freising, Germany.
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48
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Li C, Wei Z, Fan Y, Huang W, Su Y, Li H, Dong Z, Fukuda M, Khater M, Wu G. The GTPase Rab43 Controls the Anterograde ER-Golgi Trafficking and Sorting of GPCRs. Cell Rep 2017; 21:1089-1101. [PMID: 29069590 PMCID: PMC6051424 DOI: 10.1016/j.celrep.2017.10.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/21/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) constitute the largest superfamily of cell-surface signaling proteins. However, mechanisms underlying their surface targeting and sorting are poorly understood. Here, we screen the Rab family of small GTPases in the surface transport of multiple GPCRs. We find that manipulation of Rab43 function significantly alters the surface presentation and signaling of all GPCRs studied without affecting non-GPCR membrane proteins. Rab43 specifically regulates the transport of nascent GPCRs from the endoplasmic reticulum (ER) to the Golgi. More interestingly, Rab43 directly interacts with GPCRs in an activation-dependent fashion. The Rab43-binding domain identified in the receptors effectively converts non-GPCR membrane protein transport into a Rab43-dependent pathway. These data reveal a crucial role for Rab43 in anterograde ER-Golgi transport of nascent GPCRs, as well as the ER sorting of GPCR members by virtue of its ability to interact directly.
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Affiliation(s)
- Chunman Li
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yi Fan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Wei Huang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yunchao Su
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Honglin Li
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Zheng Dong
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Mitsunori Fukuda
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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Sanchez-Reyes OB, Cooke ALG, Tranter DB, Rashid D, Eilers M, Reeves PJ, Smith SO. G Protein-Coupled Receptors Contain Two Conserved Packing Clusters. Biophys J 2017; 112:2315-2326. [PMID: 28591604 DOI: 10.1016/j.bpj.2017.04.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 01/01/2023] Open
Abstract
G protein-coupled receptors (GPCRs) have evolved a seven-transmembrane helix framework that is responsive to a wide range of extracellular signals. An analysis of the interior packing of family A GPCR crystal structures reveals two clusters of highly packed residues that facilitate tight transmembrane helix association. These clusters are centered on amino acid positions 2.47 and 4.53, which are highly conserved as alanine and serine, respectively. Ala2.47 mediates the interaction between helices H1 and H2, while Ser4.53 mediates the interaction between helices H3 and H4. The helical interfaces outside of these clusters are lined with residues that are more loosely packed, a structural feature that facilitates motion of helices H5, H6, and H7, which is required for receptor activation. Mutation of the conserved small side chain at position 4.53 within packing cluster 2 is shown to disrupt the structure of the visual receptor rhodopsin, whereas sites in packing cluster 1 (e.g., positions 1.46 and 2.47) are more tolerant to mutation but affect the overall stability of the protein. These findings reveal a common structural scaffold of GPCRs that is important for receptor folding and activation.
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Affiliation(s)
- Omar B Sanchez-Reyes
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York
| | - Aidan L G Cooke
- School of Biological Sciences, University of Essex, Essex, United Kingdom
| | - Dale B Tranter
- School of Biological Sciences, University of Essex, Essex, United Kingdom
| | - Dawood Rashid
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York
| | - Markus Eilers
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York
| | - Philip J Reeves
- School of Biological Sciences, University of Essex, Essex, United Kingdom.
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York.
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Prosser RS, Ye L, Pandey A, Orazietti A. Activation processes in ligand-activated G protein-coupled receptors: A case study of the adenosine A 2A receptor. Bioessays 2017; 39. [PMID: 28787091 DOI: 10.1002/bies.201700072] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Here we review concepts related to an ensemble description of G-protein-coupled receptors (GPCRs). The ensemble is characterized by both inactive and active states, whose equilibrium populations and exchange rates depend sensitively on ligand, environment, and allosteric factors. This review focuses on the adenosine A2 receptor (A2A R), a prototypical class A GPCR. 19 F Nuclear Magnetic Resonance (NMR) studies show that apo A2A R is characterized by a broad ensemble of conformers, spanning inactive to active states, and resembling states defined earlier for rhodopsin. In keeping with ideas associated with a conformational selection mechanism, addition of agonist serves to allosterically restrict the overall degrees of freedom at the G protein binding interface and bias both states and functional dynamics to facilitate G protein binding and subsequent activation. While the ligand does not necessarily "induce" activation, it does bias sampling of states, increase the cooperativity of the activation process and thus, the lifetimes of functional activation intermediates, while restricting conformational dynamics to that needed for activation.
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Affiliation(s)
- R Scott Prosser
- Department of Chemistry, University of Toronto, UTM, Mississauga, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Libin Ye
- Department of Chemistry, University of Toronto, UTM, Mississauga, ON, Canada
| | - Aditya Pandey
- Department of Chemistry, University of Toronto, UTM, Mississauga, ON, Canada
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