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Radomsky T, Anderson RC, Millar RP, Newton CL. Restoring function to inactivating G protein-coupled receptor variants in the hypothalamic-pituitary-gonadal axis 1. J Neuroendocrinol 2024; 36:e13418. [PMID: 38852954 DOI: 10.1111/jne.13418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 03/30/2024] [Accepted: 05/15/2024] [Indexed: 06/11/2024]
Abstract
G protein-coupled receptors (GPCRs) are central to the functioning of the hypothalamic-pituitary-gonadal axis (HPG axis) and include the rhodopsin-like GPCR family members, neurokinin 3 receptor, kappa-opioid receptor, kisspeptin 1 receptor, gonadotropin-releasing hormone receptor, and the gonadotropin receptors, luteinizing hormone/choriogonadotropin receptor and follicle-stimulating hormone receptor. Unsurprisingly, inactivating variants of these receptors have been implicated in a spectrum of reproductive phenotypes, including failure to undergo puberty, and infertility. Clinical induction of puberty in patients harbouring such variants is possible, but restoration of fertility is not always a realisable outcome, particularly for those patients suffering from primary hypogonadism. Thus, novel pharmaceuticals and/or a fundamental change in approach to treating these patients are required. The increasing wealth of data describing the effects of coding-region genetic variants on GPCR function has highlighted that the majority appear to be dysfunctional as a result of misfolding of the encoded receptor protein, which, in turn, results in impaired receptor trafficking through the secretory pathway to the cell surface. As such, these intracellularly retained receptors may be amenable to 'rescue' using a pharmacological chaperone (PC)-based approach. PCs are small, cell permeant molecules hypothesised to interact with misfolded intracellularly retained proteins, stabilising their folding and promoting their trafficking through the secretory pathway. In support of the use of this approach as a viable therapeutic option, it has been observed that many rescued variant GPCRs retain at least a degree of functionality when 'rescued' to the cell surface. In this review, we examine the GPCR PC research landscape, focussing on the rescue of inactivating variant GPCRs with important roles in the HPG axis, and describe what is known regarding the mechanisms by which PCs restore trafficking and function. We also discuss some of the merits and obstacles associated with taking this approach forward into a clinical setting.
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Affiliation(s)
- Tarryn Radomsky
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Ross C Anderson
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Robert P Millar
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Claire L Newton
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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Lazzaretti C, Simoni M, Casarini L, Paradiso E. Allosteric modulation of gonadotropin receptors. Front Endocrinol (Lausanne) 2023; 14:1179079. [PMID: 37305033 PMCID: PMC10248450 DOI: 10.3389/fendo.2023.1179079] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/12/2023] [Indexed: 06/13/2023] Open
Abstract
Gonadotropins regulate reproductive functions by binding to G protein-coupled receptors (FSHR and LHCGR) expressed in the gonads. They activate multiple, cell-specific signalling pathways, consisting of ligand-dependent intracellular events. Signalling cascades may be modulated by synthetic compounds which bind allosteric sites of FSHR and LHCGR or by membrane receptor interactions. Despite the hormone binding to the orthosteric site, allosteric ligands, and receptor heteromerizations may reshape intracellular signalling pattern. These molecules act as positive, negative, or neutral allosteric modulators, as well as non-competitive or inverse agonist ligands, providing a set of new compounds of a different nature and with unique pharmacological characteristics. Gonadotropin receptor allosteric modulation is gathering increasing interest from the scientific community and may be potentially exploited for clinical purposes. This review summarizes the current knowledge on gonadotropin receptor allosteric modulation and their potential, clinical use.
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Affiliation(s)
- Clara Lazzaretti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
- Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Baggiovara Hospital, Modena, Italy
| | - Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
- Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Elia Paradiso
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, Baggiovara Hospital, University of Modena and Reggio Emilia, Modena, Italy
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Anderson RC, Hanyroup S, Song YB, Mohamed-Moosa Z, van den Bout I, Schwulst AC, Kaiser UB, Millar RP, Newton CL. Functional Rescue of Inactivating Mutations of the Human Neurokinin 3 Receptor Using Pharmacological Chaperones. Int J Mol Sci 2022; 23:ijms23094587. [PMID: 35562976 PMCID: PMC9100388 DOI: 10.3390/ijms23094587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 12/04/2022] Open
Abstract
G protein-coupled receptors (GPCRs) facilitate the majority of signal transductions across cell membranes in humans, with numerous diseases attributed to inactivating GPCR mutations. Many of these mutations result in misfolding during nascent receptor synthesis in the endoplasmic reticulum (ER), resulting in intracellular retention and degradation. Pharmacological chaperones (PCs) are cell-permeant small molecules that can interact with misfolded receptors in the ER and stabilise/rescue their folding to promote ER exit and trafficking to the cell membrane. The neurokinin 3 receptor (NK3R) plays a pivotal role in the hypothalamic–pituitary–gonadal reproductive axis. We sought to determine whether NK3R missense mutations result in a loss of cell surface receptor expression and, if so, whether a cell-permeant small molecule NK3R antagonist could be repurposed as a PC to restore function to these mutants. Quantitation of cell surface expression levels of seven mutant NK3Rs identified in hypogonadal patients indicated that five had severely impaired cell surface expression. A small molecule NK3R antagonist, M8, increased cell surface expression in four of these five and resulted in post-translational receptor processing in a manner analogous to the wild type. Importantly, there was a significant improvement in receptor activation in response to neurokinin B (NKB) for all four receptors following their rescue with M8. This demonstrates that M8 may have potential for therapeutic development in the treatment of hypogonadal patients harbouring NK3R mutations. The repurposing of existing small molecule GPCR modulators as PCs represents a novel and therapeutically viable option for the treatment of disorders attributed to mutations in GPCRs that cause intracellular retention.
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Affiliation(s)
- Ross C. Anderson
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
- Correspondence:
| | - Sharika Hanyroup
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
| | - Yong Bhum Song
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.B.S.); (U.B.K.)
- Division of Research Center, Scripps Korea Antibody Institute, Chuncheon 24341, Korea
| | - Zulfiah Mohamed-Moosa
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
- Department of Anatomy and Physiology, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Pretoria 0110, South Africa
| | - Iman van den Bout
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
| | - Alexis C. Schwulst
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
| | - Ursula B. Kaiser
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (Y.B.S.); (U.B.K.)
| | - Robert P. Millar
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
- Department of Integrative Biomedical Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9JZ, UK
- School of Medicine, Medical and Biological Sciences Building, University of St Andrews, St Andrews KY16 9TF, UK
| | - Claire L. Newton
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa; (S.H.); (Z.M.-M.); (I.v.d.B.); (A.C.S.); (R.P.M.); (C.L.N.)
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Pretoria 0031, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9JZ, UK
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Haldar S, Agrawal H, Saha S, Straughn AR, Roy P, Kakar SS. Overview of follicle stimulating hormone and its receptors in reproduction and in stem cells and cancer stem cells. Int J Biol Sci 2022; 18:675-692. [PMID: 35002517 PMCID: PMC8741861 DOI: 10.7150/ijbs.63721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/21/2021] [Indexed: 11/05/2022] Open
Abstract
Follicle stimulating hormone (FSH) and its receptor (FSHR) have been reported to be responsible for several physiological functions and cancers. The responsiveness of stem cells and cancer stem cells towards the FSH-FSHR system make the function of FSH and its receptors more interesting in the context of cancer biology. This review is comprised of comprehensive information on FSH-FSHR signaling in normal physiology, gonadal stem cells, cancer cells, and potential options of utilizing FSH-FSHR system as an anti-cancer therapeutic target.
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Affiliation(s)
- Swati Haldar
- Molecular Endocrinology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India.,Current address: Drug Discovery and Development Division, Patanjali Research Institute, Haridwar, Uttarakhand 249405
| | - Himanshu Agrawal
- Molecular Endocrinology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Sarama Saha
- Department of Biochemistry, All India Institute of Medical Sciences Rishikesh, Uttarakhand 249203, India
| | - Alex R Straughn
- Department of Physiology, James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Partha Roy
- Molecular Endocrinology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Sham S Kakar
- Department of Physiology, James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
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5
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Ulloa-Aguirre A, Zariñán T, Gutiérrez-Sagal R, Tao YX. Targeting trafficking as a therapeutic avenue for misfolded GPCRs leading to endocrine diseases. Front Endocrinol (Lausanne) 2022; 13:934685. [PMID: 36093106 PMCID: PMC9452723 DOI: 10.3389/fendo.2022.934685] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/13/2022] [Indexed: 02/05/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are plasma membrane proteins associated with an array of functions. Mutations in these receptors lead to a number of genetic diseases, including diseases involving the endocrine system. A particular subset of loss-of-function mutant GPCRs are misfolded receptors unable to traffic to their site of function (i.e. the cell surface plasma membrane). Endocrine disorders in humans caused by GPCR misfolding include, among others, hypo- and hyper-gonadotropic hypogonadism, morbid obesity, familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism, X-linked nephrogenic diabetes insipidus, congenital hypothyroidism, and familial glucocorticoid resistance. Several in vitro and in vivo experimental approaches have been employed to restore function of some misfolded GPCRs linked to endocrine disfunction. The most promising approach is by employing pharmacological chaperones or pharmacoperones, which assist abnormally and incompletely folded proteins to refold correctly and adopt a more stable configuration to pass the scrutiny of the cell's quality control system, thereby correcting misrouting. This review covers the most important aspects that regulate folding and traffic of newly synthesized proteins, as well as the experimental approaches targeted to overcome protein misfolding, with special focus on GPCRs involved in endocrine diseases.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
- *Correspondence: Alfredo Ulloa-Aguirre,
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), National University of Mexico and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City, Mexico
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology & Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL, United States
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Rivero-Müller A, Huhtaniemi I. Genetic variants of gonadotrophins and their receptors: Impact on the diagnosis and management of the infertile patient. Best Pract Res Clin Endocrinol Metab 2022; 36:101596. [PMID: 34802912 DOI: 10.1016/j.beem.2021.101596] [Citation(s) in RCA: 2] [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] [Indexed: 12/13/2022]
Abstract
This narrative review is concerned with genetic variants of the genes encoding gonadotrophin subunits and their receptors, as well as their implications into the diagnosis and treatment of infertility. We first review briefly the basics of molecular biology and biochemistry of gonadotrophin and gonadotrophin receptor structure and function, then describe the phenotypic effects of polymorphisms and mutations of these genes, followed by diagnostic aspects. We will then summarise the information that inactivating gonadotrophin receptor mutations have provided about the controversial topic of extragonadal gonadotrophin action. Finally, we will close with the current and future therapeutic approaches on patients with gonadotrophin and their receptor mutations.
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Affiliation(s)
- Adolfo Rivero-Müller
- Department of Biochemistry and Molecular Biology, Medical University of Lublin, Lublin, 20-093, Poland
| | - Ilpo Huhtaniemi
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, W12 0NN, UK.
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Hanyroup S, Anderson RC, Nataraja S, Yu HN, Millar RP, Newton CL. Rescue of Cell Surface Expression and Signaling of Mutant Follicle-Stimulating Hormone Receptors. Endocrinology 2021; 162:6311857. [PMID: 34192304 DOI: 10.1210/endocr/bqab134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 11/19/2022]
Abstract
Mutations in G protein-coupled receptors (GPCRs) underlie numerous diseases. Many cause receptor misfolding and failure to reach the cell surface. Pharmacological chaperones are cell-permeant small molecules that engage nascent mutant GPCRs in the endoplasmic reticulum, stabilizing folding and "rescuing" cell surface expression. We previously demonstrated rescue of cell surface expression of luteinizing hormone receptor mutants by an allosteric agonist. Here we demonstrate that a similar approach can be employed to rescue mutant follicle-stimulating hormone receptors (FSHRs) with poor cell surface expression using a small-molecule FSHR agonist, CAN1404. Seventeen FSHR mutations described in patients with reproductive dysfunction were expressed in HEK 293T cells, and cell surface expression was determined by enzyme-linked immunosorbent assay of epitope-tagged FSHRs before/after treatment with CAN1404. Cell surface expression was severely reduced to ≤18% of wild-type (WT) for 11, modestly reduced to 66% to 84% of WT for 4, and not reduced for 2. Of the 11 with severely reduced cell surface expression, restoration to ≥57% of WT levels was achieved for 6 by treatment with 1 µM CAN1404 for 24 h, and a corresponding increase in FSH-induced signaling was observed for 4 of these, indicating restored functionality. Therefore, CAN1404 acts as a pharmacological chaperone and can rescue cell surface expression and function of certain mutant FSHRs with severely reduced cell surface expression. These findings aid in advancing the understanding of the effects of genetic mutations on GPCR function and provide a proof of therapeutic principle for FSHR pharmacological chaperones.
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Affiliation(s)
- Sharika Hanyroup
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Ross C Anderson
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | | | | | - Robert P Millar
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Integrative Biomedical Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- School of Medicine, Medical and Biological Sciences Building, University of St Andrews, St Andrews, UK
| | - Claire L Newton
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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Ulloa-Aguirre A, Zariñán T, Jardón-Valadez E. Misfolded G Protein-Coupled Receptors and Endocrine Disease. Molecular Mechanisms and Therapeutic Prospects. Int J Mol Sci 2021; 22:ijms222212329. [PMID: 34830210 PMCID: PMC8622668 DOI: 10.3390/ijms222212329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/28/2021] [Accepted: 10/01/2021] [Indexed: 11/30/2022] Open
Abstract
Misfolding of G protein-coupled receptors (GPCRs) caused by mutations frequently leads to disease due to intracellular trapping of the conformationally abnormal receptor. Several endocrine diseases due to inactivating mutations in GPCRs have been described, including X-linked nephrogenic diabetes insipidus, thyroid disorders, familial hypocalciuric hypercalcemia, obesity, familial glucocorticoid deficiency [melanocortin-2 receptor, MC2R (also known as adrenocorticotropin receptor, ACTHR), and reproductive disorders. In these mutant receptors, misfolding leads to endoplasmic reticulum retention, increased intracellular degradation, and deficient trafficking of the abnormal receptor to the cell surface plasma membrane, causing inability of the receptor to interact with agonists and trigger intracellular signaling. In this review, we discuss the mechanisms whereby mutations in GPCRs involved in endocrine function in humans lead to misfolding, decreased plasma membrane expression of the receptor protein, and loss-of-function diseases, and also describe several experimental approaches employed to rescue trafficking and function of the misfolded receptors. Special attention is given to misfolded GPCRs that regulate reproductive function, given the key role played by these particular membrane receptors in sexual development and fertility, and recent reports on promising therapeutic interventions targeting trafficking of these defective proteins to rescue completely or partially their normal function.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City 14080, Mexico;
- Correspondence:
| | - Teresa Zariñán
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición SZ, Mexico City 14080, Mexico;
| | - Eduardo Jardón-Valadez
- Departamento de Recursos de la Tierra, Universidad Autónoma Metropolitana-Lerma, Lerma de Villada 52005, Estado de México, Mexico;
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Bustad HJ, Kallio JP, Vorland M, Fiorentino V, Sandberg S, Schmitt C, Aarsand AK, Martinez A. Acute Intermittent Porphyria: An Overview of Therapy Developments and Future Perspectives Focusing on Stabilisation of HMBS and Proteostasis Regulators. Int J Mol Sci 2021; 22:E675. [PMID: 33445488 PMCID: PMC7827610 DOI: 10.3390/ijms22020675] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease with low clinical penetrance, caused by mutations in the hydroxymethylbilane synthase (HMBS) gene, which encodes the third enzyme in the haem biosynthesis pathway. In susceptible HMBS mutation carriers, triggering factors such as hormonal changes and commonly used drugs induce an overproduction and accumulation of toxic haem precursors in the liver. Clinically, this presents as acute attacks characterised by severe abdominal pain and a wide array of neurological and psychiatric symptoms, and, in the long-term setting, the development of primary liver cancer, hypertension and kidney failure. Treatment options are few, and therapies preventing the development of symptomatic disease and long-term complications are non-existent. Here, we provide an overview of the disorder and treatments already in use in clinical practice, in addition to other therapies under development or in the pipeline. We also introduce the pathomechanistic effects of HMBS mutations, and present and discuss emerging therapeutic options based on HMBS stabilisation and the regulation of proteostasis. These are novel mechanistic therapeutic approaches with the potential of prophylactic correction of the disease by totally or partially recovering the enzyme functionality. The present scenario appears promising for upcoming patient-tailored interventions in AIP.
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Affiliation(s)
- Helene J. Bustad
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
| | - Juha P. Kallio
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
| | - Marta Vorland
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
| | - Valeria Fiorentino
- INSERM U1149, Center for Research on Inflammation (CRI), Université de Paris, 75018 Paris, France; (V.F.); (C.S.)
| | - Sverre Sandberg
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, 5009 Bergen, Norway
| | - Caroline Schmitt
- INSERM U1149, Center for Research on Inflammation (CRI), Université de Paris, 75018 Paris, France; (V.F.); (C.S.)
- Assistance Publique Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, 92700 Colombes, France
| | - Aasne K. Aarsand
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, 5009 Bergen, Norway
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
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Newton CL, Anderson RC, Kreuchwig A, Krause G, Katz AA, Millar RP. Rescue of Function of Mutant Luteinising Hormone Receptors with Deficiencies in Cell Surface Expression, Hormone Binding, and Hormone Signalling. Neuroendocrinology 2021; 111:451-464. [PMID: 32316022 DOI: 10.1159/000508000] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/18/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION G protein-coupled receptor (GPCR) mutations are implicated in many diseases. Most inactivating mutations cause receptor misfolding and prevent trafficking to the plasma membrane. Pharmacological chaperones can "rescue" cell surface expression of such mutants, presumably by stabilising correct folding of the nascent protein. OBJECTIVE Here we examine the scope of intracellularly retained luteinising hormone receptor (LHR) mutants that can be "rescued" by the pharmacological chaperone LHR-Chap, and whether this allosteric agonist can also restore the function of mutant LHRs with deficiencies in hormone binding or hormone-induced signalling. METHODS Mutant LHRs were expressed in HEK 293-T cells. Cell surface expression/localisation, hormone binding, and hCG/LHR-Chap signalling were determined by ELISA, radioligand binding, and inositol phosphate accumulation assays, respectively. Molecular modelling predicted LHR-Chap interactions. RESULTS LHR-Chap increased cell surface expression of a subset of retained mutants located in transmembrane helices predicted to be stabilised by LHR-Chap binding. For 3 (T4613.47I, L5024.61P, and S6167.46Y) hCG-responsiveness was increased following treatment. LHRs with mutations in the hormone-binding site (C131ECDR and I152ECDT) or in the hinge region (E354HingeK) had good cell surface expression but poor response to hormone stimulation, yet were responsive to allosteric activation by LHR-Chap. CONCLUSIONS LHR-Chap, in addition to rescuing cell surface expression of intracellularly retained LHR mutants, can rescue function in mutant receptors with binding and signalling deficiencies that have normal cell surface expression. This demonstration of rescue of multiple elements of LHR dysfunction arising from inactivating mutations offers exceptional potential for treating patients with diseases arising from GPCR mutations in general.
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Affiliation(s)
- Claire Louise Newton
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa,
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa,
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom,
| | - Ross Calley Anderson
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Annika Kreuchwig
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Gerd Krause
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Arieh Anthony Katz
- UCT Receptor Biology Research Unit and SAMRC Gynaecology Cancer Research Centre, Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Robert Peter Millar
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- School of Medicine, University of St Andrews, St Andrews, United Kingdom
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11
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Banerjee AA, Joseph S, Mahale SD. From cell surface to signalling and back: the life of the mammalian FSH receptor. FEBS J 2020; 288:2673-2696. [DOI: 10.1111/febs.15649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Antara A. Banerjee
- Division of Structural Biology National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
| | - Shaini Joseph
- Genetic Research Center National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
| | - Smita D. Mahale
- Division of Structural Biology National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
- ICMR Biomedical Informatics Centre National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
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12
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A 5-mer peptide derived from hinge region of hFSHR can function as positive allosteric modulator in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183492. [PMID: 33065137 DOI: 10.1016/j.bbamem.2020.183492] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/01/2020] [Accepted: 09/28/2020] [Indexed: 12/17/2022]
Abstract
Interaction of follicle stimulating hormone (FSH) with its cognate receptor (FSHR) is critical for maintaining reproductive health. FSHR has a large extracellular domain (ECD), composed of leucine rich repeats (LRRs) and hinge region, a transmembrane domain (TMD) and a short C-terminal domain (CTD). In this study, we have identified a short peptidic stretch in the hinge region (hFSHR(271-275)), through extensive computational modeling, docking and MD simulations, that is capable of independently interacting with the extracellular loops of FSHR(TMD). In vitro studies revealed that FSHR(271-275) peptide increased binding of [125I]-FSH to rat Fshr as well as FSH-induced cAMP production. Administration of FSHR(271-275) peptide in immature female rats significantly increased FSH-mediated ovarian weight gain and promoted granulosa cell proliferation. In summary, the results demonstrate that the synthetic peptide corresponding to amino acids 271-275 of hFSHR-hinge region stimulates FSH-FSHR interaction and behaves as positive allosteric modulator of FSHR. The study also lends evidence to the existing proposition that hinge region maintains the receptor in an inactive conformation in the absence of its ligand by engaging in intramolecular interactions with extracellular loops of TMD.
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13
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Bousfield GR, Harvey DJ. Follicle-Stimulating Hormone Glycobiology. Endocrinology 2019; 160:1515-1535. [PMID: 31127275 PMCID: PMC6534497 DOI: 10.1210/en.2019-00001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023]
Abstract
FSH glycosylation varies in two functionally important aspects: microheterogeneity, resulting from oligosaccharide structure variation, and macroheterogeneity, arising from partial FSHβ subunit glycosylation. Although advances in mass spectrometry permit extensive characterization of FSH glycan populations, microheterogeneity remains difficult to illustrate, and comparisons between different studies are challenging because no standard format exists for rendering oligosaccharide structures. FSH microheterogeneity is illustrated using a consistent glycan diagram format to illustrate the large array of structures associated with one hormone. This is extended to commercially available recombinant FSH preparations, which exhibit greatly reduced microheterogeneity at three of four glycosylation sites. Macroheterogeneity is demonstrated by electrophoretic mobility shifts due to the absence of FSHβ glycans that can be assessed by Western blotting of immunopurified FSH. Initially, macroheterogeneity was hoped to matter more than microheterogeneity. However, it now appears that both forms of carbohydrate heterogeneity have to be taken into consideration. FSH glycosylation can reduce its apparent affinity for its cognate receptor by delaying initial interaction with the receptor and limiting access to all of the available binding sites. This is followed by impaired cellular signaling responses that may be related to reduced receptor occupancy or biased signaling. To resolve these alternatives, well-characterized FSH glycoform preparations are necessary.
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Affiliation(s)
- George R Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, Kansas
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
| | - David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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15
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Modulation of proteostasis and protein trafficking: a therapeutic avenue for misfolded G protein-coupled receptors causing disease in humans. Emerg Top Life Sci 2019; 3:39-52. [PMID: 33523195 DOI: 10.1042/etls20180055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/17/2022]
Abstract
Proteostasis refers to the process whereby the cell maintains in equilibrium the protein content of different compartments. This system consists of a highly interconnected network intended to efficiently regulate the synthesis, folding, trafficking, and degradation of newly synthesized proteins. Molecular chaperones are key players of the proteostasis network. These proteins assist in the assembly and folding processes of newly synthesized proteins in a concerted manner to achieve a three-dimensional structure compatible with export from the endoplasmic reticulum to other cell compartments. Pharmacologic interventions intended to modulate the proteostasis network and tackle the devastating effects of conformational diseases caused by protein misfolding are under development. These include small molecules called pharmacoperones, which are highly specific toward the target protein serving as a molecular framework to cause misfolded mutant proteins to fold and adopt a stable conformation suitable for passing the scrutiny of the quality control system and reach its correct location within the cell. Here, we review the main components of the proteostasis network and how pharmacoperones may be employed to correct misfolding of two G protein-coupled receptors, the vasopressin 2 receptor and the gonadotropin-releasing hormone receptor, whose mutations lead to X-linked nephrogenic diabetes insipidus and congenital hypogonadotropic hypogonadism in humans respectively.
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16
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Tao YX, Conn PM. Pharmacoperones as Novel Therapeutics for Diverse Protein Conformational Diseases. Physiol Rev 2018; 98:697-725. [PMID: 29442594 DOI: 10.1152/physrev.00029.2016] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
After synthesis, proteins are folded into their native conformations aided by molecular chaperones. Dysfunction in folding caused by genetic mutations in numerous genes causes protein conformational diseases. Membrane proteins are more prone to misfolding due to their more intricate folding than soluble proteins. Misfolded proteins are detected by the cellular quality control systems, especially in the endoplasmic reticulum, and proteins may be retained there for eventual degradation by the ubiquitin-proteasome system or through autophagy. Some misfolded proteins aggregate, leading to pathologies in numerous neurological diseases. In vitro, modulating mutant protein folding by altering molecular chaperone expression can ameliorate some misfolding. Some small molecules known as chemical chaperones also correct mutant protein misfolding in vitro and in vivo. However, due to their lack of specificity, their potential as therapeutics is limited. Another class of compounds, known as pharmacological chaperones (pharmacoperones), binds with high specificity to misfolded proteins, either as enzyme substrates or receptor ligands, leading to decreased folding energy barriers and correction of the misfolding. Because many of the misfolded proteins are misrouted but do not have defects in function per se, pharmacoperones have promising potential in advancing to the clinic as therapeutics, since correcting routing may ameliorate the underlying mechanism of disease. This review will comprehensively summarize this exciting area of research, surveying the literature from in vitro studies in cell lines to transgenic animal models and clinical trials in several protein misfolding diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
| | - P Michael Conn
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
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Nataraja S, Sriraman V, Palmer S. Allosteric Regulation of the Follicle-Stimulating Hormone Receptor. Endocrinology 2018; 159:2704-2716. [PMID: 29800292 DOI: 10.1210/en.2018-00317] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 05/16/2018] [Indexed: 01/08/2023]
Abstract
Follicle-stimulating hormone receptor (FSHR) belongs to the leucine-rich repeat family of the G protein-coupled receptor (LGR), which includes the glycoprotein hormone receptors luteinizing hormone receptor, thyrotropin receptor, and other LGRs 4, 5, 6, and 7. FSH is the key regulator of folliculogenesis in females and spermatogenesis in males. FSH elicits its physiological response through its cognate receptor on the cell surface. Binding of the hormone FSH to its receptor FSHR brings about conformational changes in the receptor that are transduced through the transmembrane domain to the intracellular region, where the downstream effector interaction takes place, leading to activation of the downstream signaling cascade. Identification of small molecules that could activate or antagonize FSHR provided interesting tools to study the signal transduction mechanism of the receptor. However, because of the nature of the ligand-receptor interaction of FSH-FSHR, which contains multiple sites in the extracellular binding domain, most of the small-molecule modulators of FSHR are unable to bind to the orthosteric site of the receptors. Rather they modulate receptor activation through allosteric sites in the transmembrane region. This review will discuss allosteric modulation of FSHR primarily through the discovery of small-molecule modulators, focusing on current data on the status of development and the utility of these as tools to better understand signaling mechanisms.
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18
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Ulloa-Aguirre A, Zariñán T, Gutiérrez-Sagal R, Dias JA. Intracellular Trafficking of Gonadotropin Receptors in Health and Disease. Handb Exp Pharmacol 2018; 245:1-39. [PMID: 29063275 DOI: 10.1007/164_2017_49] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gonadotropin receptors belong to the highly conserved subfamily of the G protein-coupled receptor (GPCR) superfamily, the so-called Rhodopsin-like family (class A), which is the largest class of GPCRs and currently a major drug target. Both the follicle-stimulating hormone receptor (FSHR) and the luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) are mainly located in the gonads where they play key functions associated to essential reproductive functions. As any other protein, gonadotropin receptors must be properly folded into a mature tertiary conformation compatible with quaternary assembly and endoplasmic reticulum export to the cell surface plasma membrane. Several primary and secondary structural features, including presence of particular amino acid residues and short motifs and in addition, posttranslational modifications, regulate intracellular trafficking of gonadotropin receptors to the plasma membrane as well as internalization and recycling of the receptor back to the cell surface after activation by agonist. Inactivating mutations of gonadotropin receptors may derive from receptor misfolding and lead to absent or reduced plasma membrane expression of the altered receptor, thereby manifesting an array of phenotypical abnormalities mostly characterized by reproductive failure and/or abnormal or absence of development of secondary sex characteristics. In this chapter we review the structural requirements necessary for intracellular trafficking of the gonadotropin receptors, and describe how mutations in these receptors may lead to receptor misfolding and disease in humans.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico.
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - James A Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
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Abstract
Pharmacological chaperones (PCs) are small molecules that bind to nascent protein targets to facilitate their biogenesis. The ability of PCs to assist in the folding and subsequent forward trafficking of disease-causative protein misfolding mutants has opened new avenues for the treatment of conformational diseases such as cystic fibrosis and lysosomal storage disorders. In this chapter, an overview of the use of PCs for the treatment of conformational disorders is provided. Beyond the therapeutic application of PCs for the treatment of these disorders, pharmacological chaperoning of wild-type integral membrane proteins is discussed. Central to this discussion is the notion that the endoplasmic reticulum is a reservoir of viable but inefficiently processed wild-type protein folding intermediates whose biogenesis can be facilitated by PCs to increase functional pools. To date, the potential therapeutic use of PCs to enhance the biogenesis of wild-type proteins has received little attention. Here the rationale for the development of PCs that target WT proteins is discussed. Also considered is the likelihood that some commonly used therapeutic agents may exert unrecognized pharmacological chaperoning activity on wild-type targets in patient populations.
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Affiliation(s)
- Nancy J Leidenheimer
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA, USA.
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20
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Mouillac B, Mendre C. Pharmacological Chaperones as Potential Therapeutic Strategies for Misfolded Mutant Vasopressin Receptors. Handb Exp Pharmacol 2018; 245:63-83. [PMID: 28939971 DOI: 10.1007/164_2017_50] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pharmacological chaperones recently opened new possibilities in G protein-coupled receptor drug discovery. Even more interestingly, some unique ligands combine pharmacological chaperoning and biased agonism properties, boosting their therapeutic interest in many human diseases resulting from G protein-coupled receptor mutation and misfolding. These compounds displaying dual characteristics would constitute a perfect treatment for congenital Nephrogenic Diabetes Insipidus, a typical conformational disease. This X-linked genetic pathology is mostly associated with inactivating mutations of the renal arginine-vasopressin V2 receptor leading to misfolding and intracellular retention of the receptor, causing the inability of patients to concentrate their urine in response to the antidiuretic hormone. Cell-permeable pharmacological chaperones have been successfully challenged to restore plasma membrane localization of many V2 receptor mutants. In addition, different classes of specific ligands such as antagonists, agonists as well as biased agonists of the V2 receptor have proven their usefulness in rescuing mutant receptor function. This is particularly relevant for small-molecule biased agonists which only trigger Gs protein activation and cyclic adenosine monophosphate production, the V2-induced signaling pathway responsible for water reabsorption. In parallel, high-throughput screening assays based on receptor trafficking rescue approaches have been developed to discover novel V2 pharmacological chaperone molecules from different chemical libraries. These new hit compounds, which still need to be pharmacologically characterized and functionally tested in vivo, represent promising candidates for the treatment of congenital Nephrogenic Diabetes Insipidus.
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Affiliation(s)
- Bernard Mouillac
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 141 rue de la cardonille, 34094, Montpellier Cedex 05, France.
| | - Christiane Mendre
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 141 rue de la cardonille, 34094, Montpellier Cedex 05, France
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Anderson RC, Newton CL, Millar RP. Small Molecule Follicle-Stimulating Hormone Receptor Agonists and Antagonists. Front Endocrinol (Lausanne) 2018; 9:757. [PMID: 30728807 PMCID: PMC6352558 DOI: 10.3389/fendo.2018.00757] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/29/2018] [Indexed: 12/19/2022] Open
Abstract
The follicle-stimulating hormone receptor (FSHR) has been targeted therapeutically for decades, due to its pivotal role in reproduction. To date, only purified and recombinant/biosimilar FSH have been used to target FSHR in assisted reproduction, with the exception of corifollitropin alfa; a modified gonadotropin in which the FSH beta subunit is joined to the C-terminal peptide of the human choriogonadotropin beta subunit, to extend serum half-life. Assisted reproduction protocols usually entail the trauma of multiple injections of FSH to initiate and promote folliculogenesis, which has prompted the development of a number of orally-available low molecular weight (LMW) chemical scaffolds targeting the FSHR. Furthermore, the recently documented roles of the FSHR in diverse extragonadal tissues, including cancer, fat metabolism, and bone density regulation, has highlighted the potential utility of LMW modulators of FSHR activity. Despite these chemical scaffolds encompassing a spectrum of in vitro and in vivo activities and pharmacological profiles, none have yet reached the clinic. In this review we discuss the major chemical classes of LMW molecules targeting the FSHR, and document their activity profiles and current status of development, in addition to discussing potential clinical applications.
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Affiliation(s)
- Ross C. Anderson
- Centre for Neuroendocrinology, Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- *Correspondence: Ross C. Anderson
| | - Claire L. Newton
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Robert P. Millar
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Institute of Infectious Disease and Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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22
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Abstract
The gonadotropin receptors (luteinising hormone receptor; LHR and follicle-stimulating hormone receptor; FSHR) are G protein-coupled receptors (GPCRs) that play an important role in the endocrine control of reproduction. Thus genetic mutations that cause impaired function of these receptors have been implicated in a number of reproductive disorders. Disease-causing genetic mutations in GPCRs frequently result in intracellular retention and degradation of the nascent protein through misfolding and subsequent recognition by cellular quality control machinery. The discovery and development of novel compounds termed pharmacological chaperones (pharmacoperones) that can stabilise misfolded receptors and restore trafficking and plasma membrane expression are therefore of great interest clinically, and promising in vitro data describing the pharmacoperone rescue of a number of intracellularly retained mutant GPCRs has provided a platform for taking these compounds into in vivo trials. Thienopyrimidine small molecule allosteric gonadotropin receptor agonists (Org 42599 and Org 41841) have been demonstrated to have pharmacoperone activity. These compounds can rescue cell surface expression and in many cases, hormone responsiveness, of a range of retained mutant gonadotropin receptors. Should gonadotropin receptor selectivity of these compounds be improved, they could offer therapeutic benefit to subsets of patients suffering from reproductive disorders attributed to defective gonadotropin receptor trafficking.
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Affiliation(s)
- Claire L Newton
- Centre for Neuroendocrinology and Department of Immunology, Faculty of Health Sciences, University of Pretoria, PO Box 2034, Pretoria, 0001, South Africa.
| | - Ross C Anderson
- Centre for Neuroendocrinology and Department of Immunology, Faculty of Health Sciences, University of Pretoria, PO Box 2034, Pretoria, 0001, South Africa
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Bousfield GR, May JV, Davis JS, Dias JA, Kumar TR. In Vivo and In Vitro Impact of Carbohydrate Variation on Human Follicle-Stimulating Hormone Function. Front Endocrinol (Lausanne) 2018; 9:216. [PMID: 29867757 PMCID: PMC5960776 DOI: 10.3389/fendo.2018.00216] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/17/2018] [Indexed: 12/11/2022] Open
Abstract
Human follicle-stimulating hormone (FSH) exhibits both macro- and microheterogeneity in its carbohydrate moieties. Macroheterogeneity results in three physiologically relevant FSHβ subunit variants, two that possess a single N-linked glycan at either one of the two βL1 loop glycosylation sites or one with both glycans. Microheterogeneity is characterized by 80 to over 100 unique oligosaccharide structures attached to each of the 3 to 4 occupied N-glycosylation sites. With respect to its receptor, partially glycosylated (hypo-glycosylated) FSH variants exhibit higher association rates, greater apparent affinity, and greater occupancy than fully glycosylated FSH. Higher receptor binding-activity is reflected by greater in vitro bioactivity and, in some cases, greater in vivo bioactivity. Partially glycosylated pituitary FSH shows an age-related decline in abundance that may be associated with decreased fertility. In this review, we describe an integrated approach involving genetic models, in vitro signaling studies, FSH biochemistry, relevance of physiological changes in FSH glycoform abundance, and characterize the impact of FSH macroheterogeneity on fertility and reproductive aging. We will also address the controversy with regard to claims of a direct action of FSH in mediating bone loss especially at the peri- and postmenopausal stages.
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Affiliation(s)
- George R. Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, KS, United States
- *Correspondence: George R. Bousfield,
| | - Jeffrey V. May
- Department of Biological Sciences, Wichita State University, Wichita, KS, United States
| | - John S. Davis
- Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, NE, United States
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
- Nebraska-Western Iowa Health Care System, Omaha, NE, United States
| | - James A. Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, United States
| | - T. Rajendra Kumar
- Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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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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Asjad HMM, Nasrollahi-Shirazi S, Sucic S, Freissmuth M, Nanoff C. Relax, Cool Down and Scaffold: How to Restore Surface Expression of Folding-Deficient Mutant GPCRs and SLC6 Transporters. Int J Mol Sci 2017; 18:ijms18112416. [PMID: 29135937 PMCID: PMC5713384 DOI: 10.3390/ijms18112416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 11/11/2017] [Accepted: 11/12/2017] [Indexed: 01/01/2023] Open
Abstract
Many diseases arise from mutations, which impair protein folding. The study of folding-deficient variants of G protein-coupled receptors and solute carrier 6 (SLC6) transporters has shed light on the folding trajectory, how it is monitored and how misfolding can be remedied. Reducing the temperature lowers the energy barrier between folding intermediates and thereby eliminates stalling along the folding trajectory. For obvious reasons, cooling down is not a therapeutic option. One approach to rescue misfolded variants is to use membrane-permeable orthosteric ligands. Antagonists of GPCRs are—in many instances—effective pharmacochaperones: they restore cell surface expression provided that they enter cells and bind to folding intermediates. Pharmacochaperoning of SLC6 transporters is less readily achieved because the ionic conditions in the endoplasmic reticulum (ER) are not conducive to binding of typical inhibitors. The second approach is to target the heat-shock protein (HSP) relay, which monitors the folding trajectory on the cytosolic side. Importantly, orthosteric ligands and HSP-inhibitors are not mutually exclusive. In fact, pharmacochaperones and HSP-inhibitors can act in an additive or synergistic manner. This was exemplified by rescuing disease-causing, folding-deficient variants of the human dopamine transporters with the HSP70 inhibitor pifithrin-μ and the pharmacochaperone noribogaine in Drosophila melanogaster.
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Affiliation(s)
- H M Mazhar Asjad
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
| | - Shahrooz Nasrollahi-Shirazi
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
| | - Christian Nanoff
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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Beerepoot P, Nazari R, Salahpour A. Pharmacological chaperone approaches for rescuing GPCR mutants: Current state, challenges, and screening strategies. Pharmacol Res 2017; 117:242-251. [DOI: 10.1016/j.phrs.2016.12.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 12/11/2022]
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Janovick JA, Spicer TP, Smith E, Bannister TD, Kenakin T, Scampavia L, Conn PM. Receptor antagonism/agonism can be uncoupled from pharmacoperone activity. Mol Cell Endocrinol 2016; 434:176-85. [PMID: 27389877 PMCID: PMC4983495 DOI: 10.1016/j.mce.2016.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/01/2016] [Accepted: 07/01/2016] [Indexed: 10/21/2022]
Abstract
Pharmacoperones rescue misrouted mutants of the vasopressin receptor type 2 (V2R) and enable them to traffic to the correct biological locus where they function. Previously, a library of nearly 645,000 structures was interrogated with a high throughput screen; pharmacoperones were identified for V2R mutants with a view toward correcting the underlying mutational defects in nephrogenic diabetes insipidus. In the present study, an orthologous assay was used to evaluate hits from the earlier study. We found no consistent relation between antagonism or agonism and pharmacoperone activity. Active pharmacoperones were identified which had minimal antagonistic activity. This increases the therapeutic reach of these drugs, since virtually all pharmacoperone drugs reported to date were selected from peptidomimetic antagonists. Such mixed-activity drugs have a complex pharmacology limiting their therapeutic utility and requiring their removal prior to stimulation of the receptor with agonist.
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Affiliation(s)
- Jo Ann Janovick
- Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Timothy P Spicer
- Scripps Research Institute Molecular Screening Center, Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, FL, United States
| | - Emery Smith
- Scripps Research Institute Molecular Screening Center, Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, FL, United States
| | - Thomas D Bannister
- Department of Chemistry, Scripps Research Institute, Jupiter, FL, United States
| | - Terry Kenakin
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC, United States
| | - Louis Scampavia
- Scripps Research Institute Molecular Screening Center, Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, FL, United States
| | - P Michael Conn
- Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
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Bramble MS, Goldstein EH, Lipson A, Ngun T, Eskin A, Gosschalk JE, Roach L, Vashist N, Barseghyan H, Lee E, Arboleda VA, Vaiman D, Yuksel Z, Fellous M, Vilain E. A novel follicle-stimulating hormone receptor mutation causing primary ovarian failure: a fertility application of whole exome sequencing. Hum Reprod 2016; 31:905-14. [PMID: 26911863 DOI: 10.1093/humrep/dew025] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/28/2016] [Indexed: 12/11/2022] Open
Abstract
STUDY QUESTION Can whole exome sequencing (WES) and in vitro validation studies be used to find the causative genetic etiology in a patient with primary ovarian failure and infertility? SUMMARY ANSWER A novel follicle-stimulating hormone receptor (FSHR) mutation was found by WES and shown, via in vitro flow cytometry studies, to affect membrane trafficking. WHAT IS KNOWN ALREADY WES may diagnose up to 25-35% of patients with suspected disorders of sex development (DSD). FSHR mutations are an extremely rare cause of 46, XX gonadal dysgenesis with primary amenorrhea due to hypergonadotropic ovarian failure. STUDY DESIGN, SIZE, DURATION A WES study was followed by flow cytometry studies of mutant protein function. PARTICIPANTS/MATERIALS, SETTING, METHODS The study subjects were two Turkish sisters with hypergonadotropic primary amenorrhea, their parents and two unaffected sisters. The affected siblings and both parents were sequenced (trio-WES). Transient transfection of HEK 293T cells was performed with a vector containing wild-type FSHR as well as the novel FSHR variant that was discovered by WES. Cellular localization of FSHR protein as well as FSH-stimulated cyclic AMP (cAMP) production was evaluated using flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE Both affected sisters were homozygous for a previously unreported missense mutation (c.1222G>T, p.Asp408Tyr) in the second transmembrane domain of FSHR. Modeling predicted disrupted secondary structure. Flow cytometry demonstrated an average of 48% reduction in cell-surface signal detection (P < 0.01). The mean fluorescent signal for cAMP (second messenger of FSHR), stimulated by FSH, was reduced by 50% in the mutant-transfected cells (P < 0.01). LIMITATIONS, REASONS FOR CAUTION This is an in vitro validation. All novel purported genetic variants can be clinically reported only as 'variants of uncertain significance' until more patients with a similar phenotype are discovered with the same variant. WIDER IMPLICATIONS OF THE FINDINGS We report the first WES-discovered FSHR mutation, validated by quantitative flow cytometry. WES is a valuable tool for diagnosis of rare genetic diseases, and flow cytometry allows for quantitative characterization of purported variants. WES-assisted diagnosis allows for treatments aimed at the underlying molecular etiology of disease. Future studies should focus on pharmacological and assisted reproductive treatments aimed at the disrupted FSHR, so that patients with FSH resistance can be treated by personalized medicine. STUDY FUNDING/COMPETING INTERESTS E.V. is partially funded by the DSD Translational Research Network (NICHD 1R01HD068138). M.S.B. is funded by the Neuroendocrinology, Sex Differences and Reproduction training grant (NICHD 5T32HD007228). The authors have no competing interests to disclose.
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Affiliation(s)
- Matthew S Bramble
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Ellen H Goldstein
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of California Los Angeles, 10833 Le Conte Avenue, Room 24-130 CHS, Los Angeles, CA 90095, USA
| | - Allen Lipson
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Tuck Ngun
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Ascia Eskin
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Jason E Gosschalk
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Lara Roach
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Neerja Vashist
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Hayk Barseghyan
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Eric Lee
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Valerie A Arboleda
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
| | - Daniel Vaiman
- Department of Development, Reproduction, and Cancer, Institut Cochin, U1016 Inserm, University Sorbonne Paris, CNRS UMR8104, Paris, France
| | - Zafer Yuksel
- Department of Medical Genetics, Women and Children Hospital, Halkkent Mh. Fatih Sultan Mehmet Boulevard No. 23, Mersin 33240, Turkey
| | - Marc Fellous
- Department of Development, Reproduction, and Cancer, Institut Cochin, U1016 Inserm, University Sorbonne Paris, CNRS UMR8104, Paris, France
| | - Eric Vilain
- Department of Human Genetics, David Geffen School of Medicine at the University of California Los Angeles, 695 Charles E Young Drive South, Los Angeles, CA 90095, USA
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Charmandari E, Guan R, Zhang M, Silveira LG, Fan QR, Chrousos GP, Sertedaki AC, Latronico AC, Segaloff DL. Misfolding Ectodomain Mutations of the Lutropin Receptor Increase Efficacy of Hormone Stimulation. Mol Endocrinol 2015; 30:62-76. [PMID: 26554443 DOI: 10.1210/me.2015-1205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We demonstrate 2 novel mutations of the LHCGR, each homozygous, in a 46,XY patient with severe Leydig cell hypoplasia. One is a mutation in the signal peptide (p.Gln18_Leu19ins9; referred to here as SP) that results in an alteration of the coding sequence of the N terminus of the mature mutant receptor. The other mutation (p.G71R) is also within the ectodomain. Similar to many other inactivating mutations, the cell surface expression of recombinant human LHR(SP,G71R) is greatly reduced due to intracellular retention. However, we made the unusual discovery that the intrinsic efficacy for agonist-stimulated cAMP in the reduced numbers of receptors on the cell surface was greatly increased relative to the same low number of cell surface wild-type receptor. Remarkably, this appears to be a general attribute of misfolding mutations in the ectodomains, but not serpentine domains, of the gonadotropin receptors. These findings suggest that there must be a common, shared mechanism by which disparate mutations in the ectodomain that cause misfolding and therefore reduced cell surface expression concomitantly confer increased agonist efficacy to those receptor mutants on the cell surface. Our data further suggest that, due to their increased agonist efficacy, extremely small changes in cell surface expression of misfolded ectodomain mutants cause larger than expected alterations in the cellular response to agonist. Therefore, for inactivating LHCGR mutations causing ectodomain misfolding, the numbers of cell surface mutant receptors on fetal Leydig cells of 46,XY individuals exert a more exquisite effect on the relative severity of the clinical phenotypes than already appreciated.
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Affiliation(s)
- E Charmandari
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - R Guan
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - M Zhang
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - L G Silveira
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Q R Fan
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - G P Chrousos
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - A C Sertedaki
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - A C Latronico
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - D L Segaloff
- Division of Endocrinology, Metabolism and Diabetes (E.C., G.P.C., A.C.S.), First Department of Pediatrics, University of Athens Medical School, Aghia Sophia Children's Hospital, and Division of Endocrinology and Metabolism (E.C., G.P.C., A.C.S.), Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece; Department of Pharmacology (Q.R.F.), Columbia University Medical Center, New York, New York 10032; Unidade de Endocrinologia do Desenvolvimento (L.G.S., A.C.L.), Laboratório de Hormônios e Genética Molecular LIM/42, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and Department of Molecular Physiology and Biophysics (M.Z., R.G., D.L.S.), The University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
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Conn PM, Spicer TP, Scampavia L, Janovick JA. Assay strategies for identification of therapeutic leads that target protein trafficking. Trends Pharmacol Sci 2015; 36:498-505. [PMID: 26067100 DOI: 10.1016/j.tips.2015.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/09/2015] [Accepted: 05/13/2015] [Indexed: 12/12/2022]
Abstract
Receptors, enzymes, and ion channels are traditional targets of therapeutic development. A common strategy is to target these proteins with agents that either activate or suppress their activity with ligands or substrates that occupy orthosteric sites or have allosteric interactions. An alternative approach involves regulation of protein trafficking. In principle, this approach enables 'rescue' of misfolded and misrouted mutant proteins to restore function, 'shipwrecking' of undesirable proteins by targeting them for destruction, and regulation of levels of partially expressed wild type (WT) proteins at their functional sites of action. Here, we present drug discovery strategies that identify 'pharmacoperones', which are small molecules that serve as molecular templates and cause otherwise misfolded mutant proteins to fold and route correctly.
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Affiliation(s)
- P Michael Conn
- Department of Internal Medicine, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Department of Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Timothy P Spicer
- Lead Identification Division, Translational Research Institute and Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, FL, USA
| | - Louis Scampavia
- Lead Identification Division, Translational Research Institute and Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, FL, USA
| | - Jo Ann Janovick
- Department of Internal Medicine, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Department of Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Conn PM, Smith E, Spicer T, Chase P, Scampavia L, Janovick JA. A phenotypic high throughput screening assay for the identification of pharmacoperones for the gonadotropin releasing hormone receptor. Assay Drug Dev Technol 2015; 12:238-46. [PMID: 24831790 DOI: 10.1089/adt.2014.576] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We describe a phenotypic high throughput screening (HTS) calcium flux assay designed to identify pharmacoperones for the gonadotropin releasing hormone receptor (GnRHR). Pharmacoperones are target-specific, small molecules that diffuse into cells, rescue misfolded protein mutants, and restore them to function. Rescue is based on correcting the trafficking of mutants that would otherwise be retained in the endoplasmic reticulum and unable to function correctly. This approach identifies drugs with a significant degree of novelty, relying on cellular mechanisms that are not currently exploited. Development of such assays is important, since the extensive use of agonist/antagonist screens alone means that useful chemical structures may be present in existing libraries but have not been previously identified using existing methods. Our assay utilizes cell lines stably expressing a GnRHR mutant under the control of a tetracycline (OFF) transactivator. This allows us to quantitate the level of functional and properly trafficked G protein coupled receptors present in each test well. Furthermore, since we are able to turn receptor expression on and off, we can rapidly eliminate the majority of false positives from our screening results. Our data show that this approach is likely to be successful in identifying hits from large chemical libraries.
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Affiliation(s)
- P Michael Conn
- 1 Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center , Lubbock, Texas
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Nataraja SG, Yu HN, Palmer SS. Discovery and Development of Small Molecule Allosteric Modulators of Glycoprotein Hormone Receptors. Front Endocrinol (Lausanne) 2015; 6:142. [PMID: 26441832 PMCID: PMC4568768 DOI: 10.3389/fendo.2015.00142] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/31/2015] [Indexed: 11/30/2022] Open
Abstract
Glycoprotein hormones, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid-stimulating hormone (TSH) are heterodimeric proteins with a common α-subunit and hormone-specific β-subunit. These hormones are dominant regulators of reproduction and metabolic processes. Receptors for the glycoprotein hormones belong to the family of G protein-coupled receptors. FSH receptor (FSHR) and LH receptor are primarily expressed in somatic cells in ovary and testis to promote egg and sperm production in women and men, respectively. TSH receptor is expressed in thyroid cells and regulates the secretion of T3 and T4. Glycoprotein hormones bind to the large extracellular domain of the receptor and cause a conformational change in the receptor that leads to activation of more than one intracellular signaling pathway. Several small molecules have been described to activate/inhibit glycoprotein hormone receptors through allosteric sites of the receptor. Small molecule allosteric modulators have the potential to be administered orally to patients, thus improving the convenience of treatment. It has been a challenge to develop a small molecule allosteric agonist for glycoprotein hormones that can mimic the agonistic effects of the large natural ligand to activate similar signaling pathways. However, in the past few years, there have been several promising reports describing distinct chemical series with improved potency in preclinical models. In parallel, proposal of new structural model for FSHR and in silico docking studies of small molecule ligands to glycoprotein hormone receptors provide a giant leap on the understanding of the mechanism of action of the natural ligands and new chemical entities on the receptors. This review will focus on the current status of small molecule allosteric modulators of glycoprotein hormone receptors, their effects on common signaling pathways in cells, their utility for clinical application as demonstrated in preclinical models, and use of these molecules as novel tools to dissect the molecular signaling pathways of these receptors.
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Affiliation(s)
- Selvaraj G. Nataraja
- TocopheRx Inc., Burlington, MA, USA
- *Correspondence: Selvaraj G. Nataraja, TocopheRx Inc., 15 New England Executive Park, Suite 1087, Burlington, MA 01803, USA,
| | - Henry N. Yu
- TocopheRx Inc., Burlington, MA, USA
- EMD Serono Research and Development Institute Inc., Billerica, MA, USA
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Banerjee AA, Mahale SD. Role of the Extracellular and Intracellular Loops of Follicle-Stimulating Hormone Receptor in Its Function. Front Endocrinol (Lausanne) 2015; 6:110. [PMID: 26236283 PMCID: PMC4505104 DOI: 10.3389/fendo.2015.00110] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/03/2015] [Indexed: 12/20/2022] Open
Abstract
Follicle-stimulating hormone receptor (FSHR) is a leucine-rich repeat containing class A G-protein coupled receptor belonging to the subfamily of glycoprotein hormone receptors (GPHRs), which includes luteinizing hormone/choriogonadotropin receptor (LH/CGR) and thyroid-stimulating hormone receptor. Its cognate ligand, follicle-stimulating hormone binds to, and activates FSHR expressed on the surface of granulosa cells of the ovary, in females, and Sertoli cells of the testis, in males, to bring about folliculogenesis and spermatogenesis, respectively. FSHR contains a large extracellular domain (ECD) consisting of leucine-rich repeats at the N-terminal end and a hinge region at the C-terminus that connects the ECD to the membrane spanning transmembrane domain (TMD). The TMD consists of seven α-helices that are connected to each other by means of three extracellular loops (ELs) and three intracellular loops (ILs) and ends in a short-cytoplasmic tail. It is well established that the ECD is the primary hormone binding domain, whereas the TMD is the signal transducing domain. However, several studies on the ELs and ILs employing site directed mutagenesis, generation of chimeric receptors and in vitro characterization of naturally occurring mutations have proven their indispensable role in FSHR function. Their role in every phase of the life cycle of the receptor like post translational modifications, cell surface trafficking, hormone binding, activation of downstream signaling, receptor phosphorylation, hormone-receptor internalization, and recycling of hormone-receptor complex have been documented. Mutations in the loops causing dysregulation of these processes lead to pathophysiological conditions. In other GPHRs as well, the loops have been convincingly shown to contribute to various aspects of receptor function. This review article attempts to summarize the extensive contributions of FSHR loops and C-terminal tail to its function.
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Affiliation(s)
- Antara A. Banerjee
- Division of Structural Biology, National Institute for Research in Reproductive Health, Indian Council of Medical Research, Mumbai, India
| | - Smita D. Mahale
- Division of Structural Biology, National Institute for Research in Reproductive Health, Indian Council of Medical Research, Mumbai, India
- ICMR Biomedical Informatics Centre, National Institute for Research in Reproductive Health, Indian Council of Medical Research, Mumbai, India
- *Correspondence: Smita D. Mahale, Division of Structural Biology, ICMR Biomedical Informatics Centre, National Institute for Research in Reproductive Health, Indian Council of Medical Research, Jehangir Merwanji Street, Parel, Mumbai 400 012, India,
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Jiang X, Fischer D, Chen X, McKenna SD, Liu H, Sriraman V, Yu HN, Goutopoulos A, Arkinstall S, He X. Evidence for Follicle-stimulating Hormone Receptor as a Functional Trimer. J Biol Chem 2014; 289:14273-82. [PMID: 24692546 PMCID: PMC4022893 DOI: 10.1074/jbc.m114.549592] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Follicle-stimulating hormone receptor (FSHR), a G-protein coupled receptor, is an important drug target in the development of novel therapeutics for reproductive indications. The FSHR extracellular domains were observed in the crystal structure as a trimer, which enabled us to propose a novel model for the receptor activation mechanism. The model predicts that FSHR binds Asnα52-deglycosylated FSH at a 3-fold higher capacity than fully glycosylated FSH. It also predicts that, upon dissociation of the FSHR trimer into monomers, the binding of glycosylated FSH, but not deglycosylated FSH, would increase 3-fold, and that the dissociated monomers would in turn enhance FSHR binding and signaling activities by 3-fold. This study presents evidence confirming these predictions and provides crystallographic and mutagenesis data supporting the proposed model. The model also provides a mechanistic explanation to the agonist and antagonist activities of thyroid-stimulating hormone receptor autoantibodies. We conclude that FSHR exists as a functional trimer.
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Affiliation(s)
- Xuliang Jiang
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - David Fischer
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Xiaoyan Chen
- the Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Sean D McKenna
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Heli Liu
- the Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Venkataraman Sriraman
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Henry N Yu
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Andreas Goutopoulos
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Steve Arkinstall
- From the EMD Serono Research and Development Institute, Billerica, Massachusetts 01821 and
| | - Xiaolin He
- the Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Pharmacological chaperoning: a primer on mechanism and pharmacology. Pharmacol Res 2014; 83:10-9. [PMID: 24530489 DOI: 10.1016/j.phrs.2014.01.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 12/26/2022]
Abstract
Approximately forty percent of diseases are attributable to protein misfolding, including those for which genetic mutation produces misfolding mutants. Intriguingly, many of these mutants are not terminally misfolded since native-like folding, and subsequent trafficking to functional locations, can be induced by target-specific, small molecules variably termed pharmacological chaperones, pharmacoperones, or pharmacochaperones (PCs). PC targets include enzymes, receptors, transporters, and ion channels, revealing the breadth of proteins that can be engaged by ligand-assisted folding. The purpose of this review is to provide an integrated primer of the diverse mechanisms and pharmacology of PCs. In this regard, we examine the structural mechanisms that underlie PC rescue of misfolding mutants, including the ability of PCs to act as surrogates for defective intramolecular interactions and, at the intermolecular level, overcome oligomerization deficiencies and dominant negative effects, as well as influence the subunit stoichiometry of heteropentameric receptors. Not surprisingly, PC-mediated structural correction of misfolding mutants normalizes interactions with molecular chaperones that participate in protein quality control and forward-trafficking. A variety of small molecules have proven to be efficacious PCs and the advantages and disadvantages of employing orthostatic antagonists, active-site inhibitors, orthostatic agonists, and allosteric modulator PCs are considered. Also examined is the possibility that several therapeutic agents may have unrecognized activity as PCs, and this chaperoning activity may mediate/contribute to therapeutic action and/or account for adverse effects. Lastly, we explore evidence that pharmacological chaperoning exploits intrinsic ligand-assisted folding mechanisms. Given the widespread applicability of PC rescue of mutants associated with protein folding disorders, both in vitro and in vivo, the therapeutic potential of PCs is vast. This is most evident in the treatment of lysosomal storage disorders, cystic fibrosis, and nephrogenic diabetes insipidus, for which proof of principle in humans has been demonstrated.
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Jiang X, Dias JA, He X. Structural biology of glycoprotein hormones and their receptors: insights to signaling. Mol Cell Endocrinol 2014; 382:424-451. [PMID: 24001578 DOI: 10.1016/j.mce.2013.08.021] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/20/2013] [Accepted: 08/24/2013] [Indexed: 01/18/2023]
Abstract
This article reviews the progress made in the field of glycoprotein hormones (GPH) and their receptors (GPHR) by several groups of structural biologists including ourselves aiming to gain insight into GPH signaling mechanisms. The GPH family consists of four members, with follicle-stimulating hormone (FSH) being the prototypic member. GPH members belong to the cystine-knot growth factor superfamily, and their receptors (GPHR), possessing unusually large N-terminal ectodomains, belong to the G-protein coupled receptor Family A. GPHR ectodomains can be divided into two subdomains: a high-affinity hormone binding subdomain primarily centered on the N-terminus, and a second subdomain that is located on the C-terminal region of the ectodomain that is involved in signal specificity. The two subdomains unexpectedly form an integral structure comprised of leucine-rich repeats (LRRs). Following the structure determination of hCG in 1994, the field of FSH structural biology has progressively advanced. Initially, the FSH structure was determined in partially glycosylated free form in 2001, followed by a structure of FSH bound to a truncated FSHR ectodomain in 2005, and the structure of FSH bound to the entire ectodomain in 2012. Comparisons of the structures in three forms led a proposal of a two-step monomeric receptor activation mechanism. First, binding of FSH to the FSHR high-affinity hormone-binding subdomain induces a conformational change in the hormone to form a binding pocket that is specific for a sulfated-tyrosine found as sTyr 335 in FSHR. Subsequently, the sTyr is drawn into the newly formed binding pocket, producing a lever effect on a helical pivot whereby the docking sTyr provides as the 'pull & lift' force. The pivot helix is flanked by rigid LRRs and locked by two disulfide bonds on both sides: the hormone-binding subdomain on one side and the last short loop before the first transmembrane helix on the other side. The lift of the sTyr loop frees the tethered extracellular loops of the 7TM domain, thereby releasing a putative inhibitory influence of the ectodomain, ultimately leading to the activating conformation of the 7TM domain. Moreover, the data lead us to propose that FSHR exists as a trimer and to present an FSHR activation mechanism consistent with the observed trimeric crystal form. A trimeric receptor provides resolution of the enigmatic, but important, biological roles played by GPH residues that are removed from the primary FSH-binding site, as well as several important GPCR phenomena, including negative cooperativity and asymmetric activation. Further reflection pursuant to this review process revealed additional novel structural characteristics such as the identification of a 'seat' sequence in GPH. Together with the 'seatbelt', the 'seat' enables a common heteodimeric mode of association of the common α subunit non-covalently and non-specifically with each of the three different β subunits. Moreover, it was possible to establish a dimensional order that can be used to estimate LRR curvatures. A potential binding pocket for small molecular allosteric modulators in the FSHR 7TM domain has also been identified.
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Affiliation(s)
- Xuliang Jiang
- EMD Serono Research & Development Institute, Billerica, MA 01821, United States.
| | - James A Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany-SUNY, Albany, NY 12222, United States
| | - Xiaolin He
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
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Ulloa-Aguirre A, Zariñán T, Dias JA, Conn PM. Mutations in G protein-coupled receptors that impact receptor trafficking and reproductive function. Mol Cell Endocrinol 2014; 382:411-423. [PMID: 23806559 PMCID: PMC3844050 DOI: 10.1016/j.mce.2013.06.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 05/28/2013] [Accepted: 06/17/2013] [Indexed: 11/15/2022]
Abstract
G protein coupled receptors (GPCRs) are a large superfamily of integral cell surface plasma membrane proteins that play key roles in transducing extracellular signals, including sensory stimuli, hormones, neurotransmitters, or paracrine factors into the intracellular environment through the activation of one or more heterotrimeric G proteins. Structural alterations provoked by mutations or variations in the genes coding for GPCRs may lead to misfolding, altered plasma membrane expression of the receptor protein and frequently to disease. A number of GPCRs regulate reproductive function at different levels; these receptors include the gonadotropin-releasing hormone receptor (GnRHR) and the gonadotropin receptors (follicle-stimulating hormone receptor and luteinizing hormone receptor), which regulate the function of the pituitary-gonadal axis. Loss-of-function mutations in these receptors may lead to hypogonadotropic or hypergonadotropic hypogonadism, which encompass a broad spectrum of clinical phenotypes. In this review we describe mutations that provoke misfolding and failure of these receptors to traffick from the endoplasmic reticulum to the plasma membrane. We also discuss some aspects related to the therapeutic potential of some target-specific drugs that selectively bind to and rescue function of misfolded mutant GnRHR and gonadotropin receptors, and that represent potentially valuable strategies to treat diseases caused by inactivating mutations of these receptors.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Division of Reproductive Health, Research Center in Population Health, National Institute of Public Health, Cuernavaca, Mexico; Divisions of Reproductive Sciences and Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA.
| | - Teresa Zariñán
- Research Unit in Reproductive Medicine, UMAE Hospital de Ginecobstetricia "Luis Castelazo Ayala", Mexico, DF, Mexico
| | - James A Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
| | - P Michael Conn
- Divisions of Reproductive Sciences and Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA; Department of Pharmacology and Physiology, Oregon Health and Science University, Beaverton, OR 97006, USA; Department of Cell and Developmental Biology, Oregon Health and Science University, Beaverton, OR 97006, USA; Department of Obstetrics and Gynecology, Oregon Health and Science University, Beaverton, OR 97006, USA
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Conn PM, Smithson DC, Hodder PS, Stewart MD, Behringer RR, Smith E, Ulloa-Aguirre A, Janovick JA. Transitioning pharmacoperones to therapeutic use: in vivo proof-of-principle and design of high throughput screens. Pharmacol Res 2013; 83:38-51. [PMID: 24373832 DOI: 10.1016/j.phrs.2013.12.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/16/2013] [Accepted: 12/16/2013] [Indexed: 12/26/2022]
Abstract
A pharmacoperone (from "pharmacological chaperone") is a small molecule that enters cells and serves as molecular scaffolding in order to cause otherwise-misfolded mutant proteins to fold and route correctly within the cell. Pharmacoperones have broad therapeutic applicability since a large number of diseases have their genesis in the misfolding of proteins and resultant misrouting within the cell. Misrouting may result in loss-of-function and, potentially, the accumulation of defective mutants in cellular compartments. Most known pharmacoperones were initially derived from receptor antagonist screens and, for this reason, present a complex pharmacology, although these are highly target specific. In this summary, we describe efforts to produce high throughput screens that identify these molecules from chemical libraries as well as a mouse model which provides proof-of-principle for in vivo protein rescue using existing pharmacoperones.
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Affiliation(s)
- P Michael Conn
- Department of Internal Medicine, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States; Department of Cell Biology, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States.
| | - David C Smithson
- Oregon Translational Research and Drug Development Institute (OTRADI), Portland, OR 97201, United States
| | - Peter S Hodder
- Translational Research Institute, Scripps Research Institute, Jupiter, FL 33458, United States
| | - M David Stewart
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States; Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, United States
| | - Richard R Behringer
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States
| | - Emery Smith
- Translational Research Institute, Scripps Research Institute, Jupiter, FL 33458, United States
| | - Alfredo Ulloa-Aguirre
- Research Support Network, Instituto Nacional de Ciencias Medicas y Nutricion, S-Z Universidad Autonoma de Mexico, Mexico, D.F., Mexico
| | - Jo Ann Janovick
- Department of Internal Medicine, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States; Department of Cell Biology, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States
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Ulloa-Aguirre A, Michael Conn P. Pharmacoperones: a new therapeutic approach for diseases caused by misfolded G protein-coupled receptors. ACTA ACUST UNITED AC 2012; 5:13-24. [PMID: 22074574 DOI: 10.2174/187221411794351851] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 11/13/2010] [Indexed: 01/10/2023]
Abstract
G Protein-coupled receptors (GPCRs) are cell membrane proteins that recognize specific chemical signals such as drugs and hormones and transduce these signals into cellular responses by activating G-proteins. As is the case for all newly synthesized proteins, GPCRs are subjected to conformational scrutiny at the endoplasmic reticulum prior to processing and trafficking to the cell surface membrane. Because of this stringent quality control screening mechanism, mutations that result in protein misfolding frequently lead to retention in the endoplasmic reticulum, aggregation or other misrouting and, eventually, to disease. This article reviews some patents and new therapeutic opportunities based on the misfolding and retention of otherwise functional GPCRs that represent promising approaches to correct conformational abnormalities leading to distinct disease states.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Research Unit in Reproductive Medicine, Hospital de Ginecobstetricia Luis Castelazo Ayala, Instituto Mexicano del Seguro Social, Av. Rio Magdalena 289, 60. piso, Col. Tizapan San Angel, C.P. 01090, Mexico D.F., Mexico.
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Heitman LH, Kleinau G, Brussee J, Krause G, Ijzerman AP. Determination of different putative allosteric binding pockets at the lutropin receptor by using diverse drug-like low molecular weight ligands. Mol Cell Endocrinol 2012; 351:326-36. [PMID: 22269095 DOI: 10.1016/j.mce.2012.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/09/2012] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
The lutropin/choriogonadotrophin receptor (LHCGR) is a family A G protein-coupled receptor (GPCR) which binds the endogenous hormone-ligands at the large extracellular domain. In contrast, several drug-like low-molecular-weight ligands (LMWs) have been reported to interact allosterically within the seven transmembrane domain (7TMD) of the LHCGR. Here, we were interested to study the putative allosteric LHCGR binding region with focus on the determination of two pockets for LMW ligands. A library of compounds was screened for their ability to modify the binding of an allosteric radiolabeled LMW agonist [³H]Org 43553. Further experimental and computational studies revealed that the putative binding pocket for a newly identified allosteric enhancer (LUF5419) and a previously described allosteric inhibitor (LUF5771) are overlapping and that this site is different from the Org 43553 binding site. The present study showed that these compounds are useful tools to reveal details on different allosteric binding sites located within the 7TMD of the LHCGR.
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Affiliation(s)
- Laura H Heitman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, University of Leiden, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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Melancon BJ, Hopkins CR, Wood MR, Emmitte KA, Niswender CM, Christopoulos A, Conn PJ, Lindsley CW. Allosteric modulation of seven transmembrane spanning receptors: theory, practice, and opportunities for central nervous system drug discovery. J Med Chem 2012; 55:1445-64. [PMID: 22148748 DOI: 10.1021/jm201139r] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Bruce J Melancon
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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Pharmacological chaperones correct misfolded GPCRs and rescue function: protein trafficking as a therapeutic target. Subcell Biochem 2012; 63:263-89. [PMID: 23161143 DOI: 10.1007/978-94-007-4765-4_14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
G-protein-coupled receptors (GPCRs) are a large superfamily of plasma membrane proteins that play central roles in transducing endocrine, neural and -sensory signals. In humans, more than 30 disorders are associated with mutations in GPCRs and these proteins are common drug development targets, with 30-50% of drugs targeting them. GPCR mutants are frequently misfolded, recognized as defective by the cellular quality control system, retained in the endoplasmic reticulum and do not traffic to the plasma membrane. The use of small molecules chaperones (pharmacological chaperones or "pharmacoperones") to rescue misfolded GPCRs has provided a new approach for treatment of human diseases caused by misfolding and misrouting. This chapter provides an overview of the molecular basis of this approach using the human gonadotropin-releasing hormone receptor (hGnRHR) as model for treatment of conformational diseases provoked by -misfolded GPCRs.
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Abstract
The LH receptor (LHR) and FSH receptor (FSHR), collectively termed the gonadotropin receptors, are members of the Family A of GPCRs. The gonadotropin receptors each contain N-linked carbohydrates that are not directly involved in hormone binding, but contribute to the proper folding, and therefore, cell surface expression of the receptor. Loss-of-function mutations of an LHR or FSHR results in decreased target cell responsiveness. Most inactivating mutations cause receptor misfolding, resulting in the retention of the mutant in its immature form in the endoplasmic reticulum. A membrane-permeable allosteric agonist of the LHR has been shown to serve as a pharmacological chaperone for misfolded and intracellularly retained LHRs by promoting their cell surface expression. Wild-type LHR and FSHR each form homodimers and heterodimers while in the ER. Therefore, when wild-type receptor is co-expressed with a misfolded mutant, the misfolded receptor dimerizes with immature wild-type receptor in the ER, causing a dominant-negative effect on cell surface expression of the mature wild-type receptor. Notably, the propensity for homodimerization is not affected by the activation status of the receptor. However, within a receptor dimer, the activity of one protomer may allosterically regulate the other protomer. Therefore, the dimerization of the gonadotropin receptors appears to be an obligate process that is part of the normal itinerary for trafficking to the cell surface and, once there, the dimerized receptors allow for additional modulations of cell signaling.
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Affiliation(s)
- Deborah L Segaloff
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA,
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Ulloa-Aguirre A, Crépieux P, Poupon A, Maurel MC, Reiter E. Novel pathways in gonadotropin receptor signaling and biased agonism. Rev Endocr Metab Disord 2011; 12:259-74. [PMID: 21526415 DOI: 10.1007/s11154-011-9176-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gonadotropins play a central role in the control of male and female reproduction. Selective agonists and antagonists of gonadotropin receptors would be of great interest for the treatment of infertility or as non steroidal contraceptive. However, to date, only native hormones are being used in assisted reproduction technologies as there is no pharmacological agent available to manipulate gonadotropin receptors. Over the last decade, there has been a growing perception of the complexity associated with gonadotropin receptors' cellular signaling. It is now clear that the Gs/cAMP/PKA pathway is not the sole mechanism that must be taken into account in order to understand these hormones' biological actions. In parallel, consistent with the emerging paradigm of biased agonism, several examples of ligand-mediated selective signaling pathway activation by gonadotropin receptors have been reported. Small molecule ligands, modulating antibodies interacting with the hormones and glycosylation variants of the native glycoproteins have all demonstrated their potential to trigger such selective signaling. Altogether, the available data and emerging concepts give rise to intriguing opportunities towards a more efficient control of reproductive function and associated disorders.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France.
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Abstract
G protein-coupled receptors (GPCRs), which includes the gonadotropin releasing hormone (GnRH) receptor (GnRHR), comprises the largest family of validated drug targets-more than half of all approved drugs derive their benefits by selective targeting of GPCRs. Most drugs in this class are either agonists or antagonists of GPCRs and high throughput screens (HTSs) have typically been designed and performed with a view toward identification of such compounds as lead drug candidates. This manuscript presents the case that valuable drugs which effect the trafficking of GPCRs may have been overlooked because pharmacoperones have been selected from existing screens that identify agonists and antagonists. A "gain of activity assay" is proposed; this assay relies on the expression of a mutant of the GnRHR that is known to be rescuable by pharmacoperone drugs, and which is restored to activity in their presence. Accordingly, "hits" are identified by the appearance of activity. The gene for the mutant is under control of tetracycline and may be prevented from being expressed. This is a valuable feature since it allows false positives to be identified. Such drugs will show apparent activity whether or not the mutant is expressed. This assay will enable identification of these drugs from chemical libraries and does not rely on their activity as agonists or antagonists.
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Affiliation(s)
- P. Michael Conn
- Division of Reproductive Sciences, Oregon National Primate Research Center, Oregon Health and Science UniversityBeaverton, OR, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science UniversityBeaverton, OR, USA
- Department of Physiology and Pharmacology, Oregon Health and Science UniversityBeaverton, OR, USA
- Department of Cell Biology and Development, Oregon Health and Science UniversityBeaverton, OR, USA
- Department of Obstetrics and Gynecology, Oregon Health and Science UniversityBeaverton, OR, USA
- *Correspondence: P. Michael Conn, Oregon National Primate Research Center, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA. e-mail:
| | - Jo Ann Janovick
- Division of Reproductive Sciences, Oregon National Primate Research Center, Oregon Health and Science UniversityBeaverton, OR, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science UniversityBeaverton, OR, USA
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Mendre C, Mouillac B. [Pharmacological chaperones: a potential therapeutic treatment for conformational diseases]. Med Sci (Paris) 2010; 26:627-35. [PMID: 20619166 DOI: 10.1051/medsci/2010266-7627] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Many genetic and neurodegenerative diseases in humans result from protein misfolding and/or aggregation. These diseases are named conformational diseases. As a result, the misfolded non functional proteins are rejected and misrouted by the cellular quality control system, and cannot play their endogenous physiological roles. Specific compounds (ligands, substrates or inhibitors) known as pharmacological chaperones are able to bind and stabilize these misfolded proteins. Their interaction allows the target proteins to escape the quality control system and to be functionally rescued. These pharmacochaperones may possess different intrinsic activity: they can be antagonists (inhibitors), agonists (activators) or allosteric modulators of the target receptors, ionic channels or enzymes. Pharmacological chaperones have obviously a therapeutic potential to treat rare diseases like cystic fibrosis, retinitis pigmentosa, nephrogenic diabetes insipidus, Fabry disease, Gaucher disease, but also for cancers and more frequent and highly invalidant neurodegenerative disorders such as Alzheimer's disease or Parkinson's disease.
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Affiliation(s)
- Christiane Mendre
- Universités Montpellier 1 et 2, 141, 34094 Montpellier Cedex 05, France.
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Conn PM, Ulloa-Aguirre A. Trafficking of G-protein-coupled receptors to the plasma membrane: insights for pharmacoperone drugs. Trends Endocrinol Metab 2010; 21:190-7. [PMID: 20005736 PMCID: PMC2831145 DOI: 10.1016/j.tem.2009.11.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/18/2022]
Abstract
G protein-coupled receptors (GPCRs) are among the most common potential targets for pharmacological design. Synthesized in the endoplasmic reticulum, they interact with endogenous chaperones that assist in folding (or can retain incorrectly folded proteins) and are transferred to the plasma membrane where they exert their physiological functions. We summarize trafficking of the gonadotropin-releasing hormone receptor (GnRHR) to the plasma membrane. The trafficking of GnRHR is among the best characterized due in part to its small size and the consequent ease of making mutant proteins. Human mutations that cause disease through the misrouting of GPCRs including GnRHR are also reviewed. Special emphasis is placed on therapeutic opportunities presented by pharmacological chaperone drugs, or pharmacoperones, that allow misrouted mutants to be routed correctly and restored to function.
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Affiliation(s)
- P Michael Conn
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA.
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Tao YX, Segaloff DL. Follicle stimulating hormone receptor mutations and reproductive disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 89:115-31. [PMID: 20374735 DOI: 10.1016/s1877-1173(09)89005-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The follicle stimulating hormone receptor (FSHR) plays a critical role in reproductive function. In the males, FSH supports spermatogenesis, whereas in females, FSH is absolutely required for ovarian follicle growth. In females, inactivating mutations in the FSHR result in ovarian dysgenesis with amenorrhea and infertility. The few males reported with severe inactivating mutations exhibited varying spermatogenic defects, but not azoospermia. While these findings may potentially suggest that FSH action is not absolutely required for spermatogenesis, it cannot be ruled out that these individuals have some residual FSHR activity. Gain-of-function mutations in the FSHR cause spontaneous ovarian hyperstimulation syndrome in females due to the inappropriate stimulation of the mutant FSHR by human choriogonadotropin.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Alabama 36849, USA
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Conn PM, Janovick JA. Drug development and the cellular quality control system. Trends Pharmacol Sci 2009; 30:228-33. [DOI: 10.1016/j.tips.2009.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 02/11/2009] [Accepted: 02/12/2009] [Indexed: 01/01/2023]
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