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Wei W, Xu Q, Wu L, Gong G, Tian Y, Huang H, Li Z. Drug development and potential targets for Cushing's syndrome. Eur J Med Chem 2024; 270:116333. [PMID: 38569434 DOI: 10.1016/j.ejmech.2024.116333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/05/2024]
Abstract
Cushing's syndrome (CS) is a complex disorder characterized by the excessive secretion of cortisol, with Cushing's disease (CD), particularly associated with pituitary tumors, exhibiting heightened morbidity and mortality. Although transsphenoidal pituitary surgery (TSS) stands as the primary treatment for CD, there is a crucial need to optimize patient prognosis. Current medical therapy serves as an adjunctive measure due to its unsatisfactory efficacy and unpredictable side effects. In this comprehensive review, we delve into recent advances in understanding the pathogenesis of CS and explore therapeutic options by conducting a critical analysis of potential drug targets and candidates. Additionally, we provide an overview of the design strategy employed in previously reported candidates, along with a summary of structure-activity relationship (SAR) analyses and their biological efficacy. This review aims to contribute valuable insights to the evolving landscape of CS research, shedding light on potential avenues for therapeutic development.
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Affiliation(s)
- Wei Wei
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Qianqian Xu
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Liuyi Wu
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Guangyue Gong
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Yucheng Tian
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China
| | - Huidan Huang
- Center of Drug Screening & Evaluation, Wannan Medical College, Wuhu, Anhui, 241000, PR China.
| | - Zhiyu Li
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, PR China.
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Klak K, Maciuszek M, Pijanowski L, Marcinkowska M, Homa J, Verburg-van Kemenade BML, Rakus K, Chadzinska M. Evolutionarily conserved mechanisms regulating stress-induced neutrophil redistribution in fish. Front Immunol 2024; 15:1330995. [PMID: 38515741 PMCID: PMC10954836 DOI: 10.3389/fimmu.2024.1330995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/21/2024] [Indexed: 03/23/2024] Open
Abstract
Introduction Stress may pose a serious challenge to immune homeostasis. Stress however also may prepare the immune system for challenges such as wounding or infection, which are likely to happen during a fight or flight stress response. Methods In common carp (Cyprinus carpio L.) we studied the stress-induced redistribution of neutrophils into circulation, and the expression of genes encoding CXC chemokines known to be involved in the regulation of neutrophil retention (CXCL12) and redistribution (CXCL8), and their receptors (CXCR4 and CXCR1-2, respectively) in blood leukocytes and in the fish hematopoietic organ - the head kidney. The potential involvement of CXC receptors and stress hormone receptors in stress-induced neutrophil redistribution was determined by an in vivo study with selective CXCR inhibitors and antagonists of the receptors involved in stress regulation: glucocorticoid/mineralocorticoid receptors (GRs/MRs), adrenergic receptors (ADRs) and the melanocortin 2 receptor (MC2R). Results The stress-induced increase of blood neutrophils was accompanied by a neutrophil decrease in the hematopoietic organs. This increase was cortisol-induced and GR-dependent. Moreover, stress upregulated the expression of genes encoding CXCL12 and CXCL8 chemokines, their receptors, and the receptor for granulocytes colony-stimulation factor (GCSFR) and matrix metalloproteinase 9 (MMP9). Blocking of the CXCR4 and CXCR1 and 2 receptors with selective inhibitors inhibited the stress-induced neutrophil redistribution and affected the expression of genes encoding CXC chemokines and CXCRs as well as GCSFR and MMP9. Discussion Our data demonstrate that acute stress leads to the mobilization of the immune system, characterized by neutrophilia. CXC chemokines and CXC receptors are involved in this stress-induced redistribution of neutrophils from the hematopoietic tissue into the peripheral blood. This phenomenon is directly regulated by interactions between cortisol and the GR/MR. Considering the pivotal importance of neutrophilic granulocytes in the first line of defense, this knowledge is important for aquaculture, but will also contribute to the mechanisms involved in the stress-induced perturbation in neutrophil redistribution as often observed in clinical practice.
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Affiliation(s)
- Katarzyna Klak
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Magdalena Maciuszek
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
| | - Lukasz Pijanowski
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
| | - Magdalena Marcinkowska
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Joanna Homa
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
| | | | - Krzysztof Rakus
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
| | - Magdalena Chadzinska
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
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Luo P, Feng W, Ma S, Dai A, Wu K, Chen X, Yuan Q, Cai X, Yang D, Wang MW, Eric Xu H, Jiang Y. Structural basis of signaling regulation of the human melanocortin-2 receptor by MRAP1. Cell Res 2023; 33:46-54. [PMID: 36588120 PMCID: PMC9810661 DOI: 10.1038/s41422-022-00751-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/08/2022] [Indexed: 01/03/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are regulated by various downstream proteins, of which the melanocortin receptor accessory protein 1 (MRAP1) is closely involved in the regulation of melanocortin receptor 2 (MC2R). Assisted by MRAP1, MC2R responds to adrenocorticotropic hormone (ACTH) and stimulates glucocorticoid biogenesis and cortisol secretion. MC2R activation plays an essential role in the hypothalamic-pituitary-adrenal (HPA) axis that regulates stress response, while its dysfunction causes glucocorticoid insufficiency- or cortisol excess-associated disorders. Here, we present a cryo-electron microscopy (cryo-EM) structure of the ACTH-bound MC2R-Gs-MRAP1 complex. Our structure, together with mutagenesis analysis, reveals a unique sharp kink at the extracellular region of MRAP1 and the 'seat-belt' effect of MRAP1 on stabilizing ACTH binding and MC2R activation. Mechanisms of ACTH recognition by MC2R and receptor activation are also demonstrated. These findings deepen our understanding of GPCR regulation by accessory proteins and provide valuable insights into the ab initio design of therapeutic agents targeting MC2R.
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Affiliation(s)
- Ping Luo
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenbo Feng
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shanshan Ma
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Antao Dai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kai Wu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xianyue Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Qingning Yuan
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoqing Cai
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Dehua Yang
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - H Eric Xu
- The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Yi Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- Lingang Laboratory, Shanghai, China.
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Forfar R, Hussain M, Khurana P, Cook J, Lewis S, Popat D, Jackson D, McIver E, Jerman J, Taylor D, Clark AJL, Chan LF. Identification of a novel specific small-molecule melanocortin-2-receptor antagonist. Endocr Connect 2022; 11:e220338. [PMID: 36515667 PMCID: PMC9641778 DOI: 10.1530/ec-22-0338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 12/15/2022]
Abstract
The overproduction of adrenocorticotropic hormone (ACTH), in conditions such as Cushing's disease and congenital adrenal hyperplasia (CAH), leads to significant morbidity. Current treatment with glucocorticoids does not adequately suppress plasma ACTH, resulting in excess adrenal androgen production. At present, there is no effective medical treatment in clinical use that would directly block the action of ACTH. Such a therapy would be of great clinical value. ACTH acts via a highly selective receptor, the melanocortin-2 receptor (MC2R) associated with its accessory protein MRAP. ACTH is the only known naturally occurring agonist for this receptor. This lack of redundancy and the high degree of ligand specificity suggest that antagonism of this receptor could provide a useful therapeutic strategy in the treatment of conditions of ACTH excess. To this end, we screened an extensive library of low-molecular-weight drug-like compounds for MC2R antagonist activity using a high-throughput homogeneous time-resolved fluorescence cAMP assay in Chinese hamster ovary cells stably co-expressing human MC2R and MRAP. Hits that demonstrated MC2R antagonist properties were counter-screened against the β2 adrenergic receptor and dose-response analysis undertaken. This led to the identification of a highly specific MC2R antagonist capable of antagonising ACTH-induced progesterone release in murine Y-1 adrenal cells and having selectivity for MC2R amongst the human melanocortin receptors. This work provides a foundation for the clinical investigation of small-molecule ACTH antagonists as therapeutic agents and proof of concept for the screening and discovery of such compounds.
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Affiliation(s)
- Rachel Forfar
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Mashal Hussain
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Puneet Khurana
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Jennifer Cook
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Steve Lewis
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Dillon Popat
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - David Jackson
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Ed McIver
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Jeff Jerman
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Debra Taylor
- Centre for Therapeutics Discovery, LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, UK
| | - Adrian JL Clark
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Li F Chan
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
- Correspondence should be addressed to L F Chan:
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van der Valk ES, Kleinendorst L, Delhanty PJD, van der Voorn B, Visser JA, van Haelst MM, de Graaff LCG, Huisman M, White A, Ito S, Wakamatsu K, de Rijke YB, van den Akker ELT, Iyer AM, van Rossum EFC. Obesity and Hyperphagia With Increased Defective ACTH: A Novel POMC Variant. J Clin Endocrinol Metab 2022; 107:e3699-e3704. [PMID: 35737586 PMCID: PMC9797039 DOI: 10.1210/clinem/dgac342] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Patients with pro-opiomelanocortin (POMC) defects generally present with early-onset obesity, hyperphagia, hypopigmentation and adrenocorticotropin (ACTH) deficiency. Rodent models suggest that adequate cleavage of ACTH to α-melanocortin-stimulating hormone (α-MSH) and desacetyl-α-melanocortin-stimulating hormone (d-α-MSH) by prohormone convertase 2 at the KKRR region is required for regulating food intake and energy balance. METHODS We present 2 sisters with a novel POMC gene variant, leading to an ACTH defect at the prohormone convertase 2 cleavage site, and performed functional studies of this variant. RESULTS The patients had obesity, hyperphagia and hypocortisolism, with markerly raised levels of ACTH but unaffected pigmentation. Their ACTH has reduced potency to stimulate the melanocortin (MC) 2 receptor, explaining their hypocortisolism. CONCLUSION The hyperphagia and obesity support evidence that adequate cleavage of ACTH to α-MSH and d-α-MSH is also required in humans for feeding control.
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Affiliation(s)
- Eline S van der Valk
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | | | | | - Bibian van der Voorn
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Jenny A Visser
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - M M van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1100 DD Amsterdam, the Netherlands
| | - Laura C G de Graaff
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Martin Huisman
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Anne White
- Divison of Diabetes, Endocrinology & Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, 470-1192, Japan
| | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, 470-1192, Japan
| | - Yolanda B de Rijke
- Department of Clinical Chemistry, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Erica L T van den Akker
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Anand M Iyer
- Obesity Centre CGG, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
- Department of Internal Medicine, Division of Endocrinology, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, the Netherlands
| | - Elisabeth F C van Rossum
- Correspondence: Elisabeth F. C. van Rossum, MD, PhD, Obesity Center CGG (Centrum Gezond Gewicht), Erasmus MC, University Medical Center Rotterdam, the Netherlands, Rm Rg-5. P. O. Box 2400, 3000 CA Rotterdam, the Netherlands.
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Translational advances of melanocortin drugs: Integrating biology, chemistry and genetics. Semin Immunol 2022; 59:101603. [PMID: 35341670 DOI: 10.1016/j.smim.2022.101603] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 01/15/2023]
Abstract
Melanocortin receptors have emerged as important targets with a very unusual versatility, as their widespread distribution on multiple tissues (e.g. skin, adrenal glands, brain, immune cells, exocrine glands) together with the variety of physiological processes they control (pigmentation, cortisol release, satiety mechanism, inflammation, secretions), place this family of receptors as genuine therapeutic targets for many disorders. This review focuses in the journey of the development of melanocortin receptors as therapeutic targets from the discovery of their existence in the early 1990 s to the approval of the first few drugs of this class. Two major areas of development characterise the current state of melanocortin drug development: their role in obesity, recently culminated with the approval of setmelanotide, and their potential for the treatment of chronic inflammatory and autoimmune diseases like rheumatoid arthritis, multiple sclerosis or fibrosis. The pro-resolving nature of these drugs offers the advantage of acting by mimicking the way our body naturally resolves inflammation, expecting fewer side effects and a more balanced (i.e. non-immunosuppressive) response from them. Here we also review the approaches followed for the design and development of novel compounds, the importance of the GPCR nature of these receptors in the process of drug development, therapeutic value, current challenges and successes, and the potential for the implementation of precision medicine approaches through the incorporation of genetics advances.
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Hasenmajer V, Bonaventura I, Minnetti M, Sada V, Sbardella E, Isidori AM. Non-Canonical Effects of ACTH: Insights Into Adrenal Insufficiency. Front Endocrinol (Lausanne) 2021; 12:701263. [PMID: 34489864 PMCID: PMC8416901 DOI: 10.3389/fendo.2021.701263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/04/2021] [Indexed: 01/13/2023] Open
Abstract
Introduction Adrenocorticotropic hormone (ACTH) is produced from proopiomelanocortin, which is predominantly synthetized in the corticotroph and melanotroph cells of the anterior and intermediate lobes of the pituitary gland and the arcuate nucleus of the hypothalamus. Although ACTH clearly has an effect on adrenal homeostasis and maintenance of steroid hormone production, it also has extra-adrenal effects that require further elucidation. Methods We comprehensively reviewed English language articles, regardless of whether they reported the presence or absence of adrenal and extra-adrenal ACTH effects. Results In the present review, we provide an overview on the current knowledge on adrenal and extra-adrenal effects of ACTH. In the section on adrenal ACTH effects, we focused on corticosteroid rhythmicity and effects on steroidogenesis, mineralocorticoids and adrenal growth. In the section on extra-adrenal effects, we have analyzed the effects of ACTH on the osteoarticular and reproductive systems, adipocytes, immune system, brain and skin. Finally, we focused on adrenal insufficiency. Conclusions The role of ACTH in maintaining the function of the hypothalamic-pituitary-adrenal axis is well known. Conversely, if we broaden our vision and analyze its role as a potential treatment strategy in other conditions, it will be evident in the literature that researchers seem to have abandoned this aspect in studies conducted several years ago. We believe it is worth re-evaluating the role of ACTH considering its noncanonical effects on the adrenal gland itself and on extra-adrenal organs and tissues; however, this would not have been possible without the recent advances in the pertinent technologies.
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Affiliation(s)
| | | | | | | | | | - Andrea M. Isidori
- Department of Experimental Medicine, Sapienza University of Rome - Policlinico Umberto I Hospital, Rome, Italy
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Yang Y, Harmon CM. Molecular determinants of ACTH receptor for ligand selectivity. Mol Cell Endocrinol 2020; 503:110688. [PMID: 31866318 DOI: 10.1016/j.mce.2019.110688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/03/2019] [Accepted: 12/16/2019] [Indexed: 01/04/2023]
Abstract
The adrenocorticotropic hormone (ACTH) receptor, known as the melanocortin-2 receptor (MC2R), plays a key role in regulating adrenocortical function. ACTH receptor is a subtype of the melanocortin receptor family which is a member of the G-protein coupled receptor (GPCR) superfamily. ACTH receptor has unique characteristics among MCRs. α-MSH, β-MSH, γ-MSH and ACTH are agonists for MCRs but only ACTH is the agonist for ACTH receptor. In addition, the melanocortin receptor accessory protein (MRAP) is required for ACTH receptor expression at cell surface and function. In this review, we summarized the information available on the relationship between ACTH and ACTH receptor and provide the latest understanding of the molecular basis of the ACTH receptor responsible for ligand selectivity and function.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, State University of New York at Buffalo, USA.
| | - Carroll M Harmon
- Department of Surgery, State University of New York at Buffalo, USA
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Schnabl K, Westermeier J, Li Y, Klingenspor M. Opposing Actions of Adrenocorticotropic Hormone and Glucocorticoids on UCP1-Mediated Respiration in Brown Adipocytes. Front Physiol 2019; 9:1931. [PMID: 30705635 PMCID: PMC6344423 DOI: 10.3389/fphys.2018.01931] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/21/2018] [Indexed: 12/23/2022] Open
Abstract
Brown fat is a potential target in the treatment of metabolic disorders as recruitment and activation of this thermogenic organ increases energy expenditure and promotes satiation. A large variety of G-protein coupled receptors, known as classical drug targets in pharmacotherapy, is expressed in brown adipocytes. In the present study, we analyzed transcriptome data for the expression of these receptors to identify potential pathways for the recruitment and activation of thermogenic capacity in brown fat. Our analysis revealed 12 Gs-coupled receptors abundantly expressed in murine brown fat. We screened ligands for these receptors in brown adipocytes for their ability to stimulate UCP1-mediated respiration and Ucp1 gene expression. Adrenocorticotropic hormone (ACTH), a ligand for the melanocortin 2 receptor (MC2R), turned out to be the most potent activator of UCP1 whereas its capability to stimulate Ucp1 gene expression was comparably low. Adrenocorticotropic hormone is the glandotropic hormone of the endocrine hypothalamus–pituitary–adrenal-axis stimulating the release of glucocorticoids in response to stress. In primary brown adipocytes ACTH acutely increased the cellular respiration rate similar to isoproterenol, a β-adrenergic receptor agonist. The effect of ACTH on brown adipocyte respiration was mediated via the MC2R as confirmed by using an antagonist. Inhibitor-based studies revealed that ACTH-induced respiration was dependent on protein kinase A and lipolysis, compatible with a rise of intracellular cAMP in response to ACTH. Furthermore, it is dependent on UCP1, as cells from UCP1-knockout mice did not respond. Taken together, ACTH is a non-adrenergic activator of murine brown adipocytes, initiating the canonical adenylyl cyclase–cAMP–protein kinase A-lipolysis-UCP1 pathway, and thus a potential target for the recruitment and activation of thermogenic capacity. Based on these findings in primary cell culture, the physiological significance might be that cold-induced ACTH in concert with norepinephrine released from sympathetic nerves contributes to BAT thermogenesis. Notably, dexamethasone attenuated isoproterenol-induced respiration. This effect increased gradually with the duration of pretreatment. In vivo, glucocorticoid release triggered by ACTH might oppose beta-adrenergic stimulation of metabolic fuel combustion in BAT and limit stress-induced hyperthermia.
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Affiliation(s)
- Katharina Schnabl
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Julia Westermeier
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Yongguo Li
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Martin Klingenspor
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
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10
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Sanders K, Mol JA, Kooistra HS, Galac S. Melanocortin 2 receptor antagonists in canine pituitary-dependent hypercortisolism: in vitro studies. Vet Res Commun 2018; 42:283-288. [PMID: 30187173 PMCID: PMC6244543 DOI: 10.1007/s11259-018-9737-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/30/2018] [Indexed: 11/16/2022]
Abstract
Canine hypercortisolism is most often caused by an ACTH-secreting pituitary adenoma (pituitary-dependent hypercortisolism; PDH). An interesting target for a selective medical treatment of PDH would be the receptor for ACTH: the melanocortin 2 receptor (MC2R). In this study we investigated whether two peptide compounds, BIM-22776 (#776) and BIM-22A299 (#299), are effective MC2R antagonists in vitro. Their effects on cortisol production and mRNA expression of steroidogenic enzymes, MC2R and melanocortin 2 receptor accessory protein (MRAP) were evaluated in primary adrenocortical cell cultures (n = 8) of normal canine adrenal glands. Cortisol production stimulated by 50 nM ACTH was dose-dependently inhibited by #299 (inhibition 90.7 ± 2.3% at 5 μM) and by #776 (inhibition 38.0 ± 5.2% at 5 μM). The ACTH-stimulated mRNA expression of steroidogenic enzymes, MC2R and MRAP was significantly inhibited by both compounds, but most potently by #299. These results indicate that canine primary cell culture is a valuable in vitro system to test MC2R antagonists, and that these compounds, but especially #299, are effective MC2R antagonists in vitro. To determine its efficacy in vivo, further studies are warranted. Antagonism of the MC2R is a promising potential treatment approach in canine PDH.
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Affiliation(s)
- Karin Sanders
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, the Netherlands.
| | - Jan A Mol
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, the Netherlands
| | - Hans S Kooistra
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, the Netherlands
| | - Sara Galac
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, the Netherlands
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Sanders K, Kooistra HS, Galac S. Treating canine Cushing's syndrome: Current options and future prospects. Vet J 2018; 241:42-51. [PMID: 30340659 DOI: 10.1016/j.tvjl.2018.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/17/2018] [Accepted: 09/25/2018] [Indexed: 12/17/2022]
Abstract
Naturally occurring hypercortisolism, also known as Cushing's syndrome, is a common endocrine disorder in dogs that can be caused by an adenocorticotrophic hormone (ACTH)-producing pituitary adenoma (pituitary-dependent hypercortisolism, PDH; 80-85% of cases), or by an adrenocortical tumor (ACT; 15-20% of cases). To determine the optimal treatment strategy, differentiating between these two main causes is essential. Good treatment options are surgical removal of the causal tumor, i.e. hypophysectomy for PDH and adrenalectomy for an ACT, or radiotherapy in cases with PDH. Because these options are not without risks, not widely available and not suitable for every patient, pharmacotherapy is often used. In cases with PDH, the steroidogenesis inhibitor trilostane is most often used. In cases with an ACT, either trilostane or the adrenocorticolytic drug mitotane can be used. Although mostly effective, both treatments have disadvantages. This review discusses the current treatment options for canine hypercortisolism, and considers their mechanism of action, efficacy, adverse effects, and effect on survival. In addition, developments in both adrenal-targeting and pituitary-targeting drugs that have the potential to become future treatment options are discussed, as a more selective and preferably also tumor-targeted approach could have many advantages for both PDH and ACTs.
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Affiliation(s)
- K Sanders
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands
| | - H S Kooistra
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands
| | - S Galac
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands.
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Abstract
INTRODUCTION Cushing's disease is a rare systemic and disabling disease due to oversecretion of adrenocorticotrophic hormone (ACTH) resulting in excess cortisol levels. Diagnosis and treatment are difficult; despite the availability of various pharmaceutical treatment options, there is an ongoing, unmet need for even more effective treatment. AREAS COVERED The present review aims at providing an overview of available drugs and presenting new developments. Focusing on the pituitary as a target, the review covers compounds targeting pituitary cell signaling or cell cycle control such as heat shock protein inhibitors (e.g. silibinin), histone deacetylase inhibitors (trichostatin A, vorinostat), kinase inhibitors (gefitinib, seliciclib), and others (such as triptolide, AT-101). Levoketoconazole and osilodrostat are in clinical testing and inhibit steroidogenesis. Blockade of ACTH receptor binding at the adrenal level is explained as a theoretical drug target. Inhibition of binding of the glucocorticoid receptor in the peripheral tissue plays a minor role due to its lack of biomonitoring options. EXPERT OPINION In our opinion, further research and drug development of pituitary-directed targets are necessary. Combination therapies may exert synergistic effects and allow for smaller and better tolerated doses, but more experience and data are needed to guide such treatment schemes.
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Affiliation(s)
- Sylvère Störmann
- a Medizinische Klinik und Poliklinik IV , Klinikum der Universität München , München , Germany
| | - Jochen Schopohl
- a Medizinische Klinik und Poliklinik IV , Klinikum der Universität München , München , Germany
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13
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Goldenberg AJ, Gehrand AL, Waples E, Jablonski M, Hoeynck B, Raff H. Effect of a melanocortin type 2 receptor (MC2R) antagonist on the corticosterone response to hypoxia and ACTH stimulation in the neonatal rat. Am J Physiol Regul Integr Comp Physiol 2018; 315:R128-R133. [PMID: 29718699 DOI: 10.1152/ajpregu.00009.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The adrenal stress response in the neonatal rat shifts from ACTH-independent to ACTH-dependent between postnatal days 2 (PD2) and 8 (PD8). This may be due to an increase in an endogenous, bioactive, nonimmunoreactive ligand to the melanocortin type 2 receptor (MC2R). GPS1574 is a newly described MC2R antagonist that we have shown to be effective in vitro. Further experimentation with GPS1574 would allow better insight into this seemingly ACTH-independent steroidogenic response in neonates. We evaluated the acute corticosterone response to hypoxia or ACTH injection following pretreatment with GPS1574 (32 mg/kg) or vehicle for GPS1574 in PD2, PD8, and PD15 rat pups. Pretreatment with GPS1574 decreased baseline corticosterone in PD2 pups but increased baseline corticosterone in PD8 and PD15 pups. GPS1574 did not attenuate the corticosterone response to hypoxia in PD2 pups and augmented the corticosterone response in PD8 and PD15 pups. GPS1574 augmented the corticosterone response to ACTH in PD2 and PD15 pups but had no significant impact on the response in PD8 pups. Baseline adrenal Mrap and Star mRNA increased from PD2 to PD15, whereas Mrap2 mRNA expression was low and did not change with age. The data suggest that GPS1574 is not a pure MC2R antagonist, but rather acts as a biasing agonist/antagonist. Its ability to attenuate or augment the adrenal response may depend on the ambient plasma ACTH concentration and/or developmental changes in early transduction steroidogenic pathway genes.
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Affiliation(s)
- Adam J Goldenberg
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin.,Department of Medicine, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Ashley L Gehrand
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin
| | - Emily Waples
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin
| | - Mack Jablonski
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin
| | - Brian Hoeynck
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin
| | - Hershel Raff
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute , Milwaukee, Wisconsin.,Department of Medicine, Medical College of Wisconsin , Milwaukee, Wisconsin.,Department of Surgery, Medical College of Wisconsin , Milwaukee, Wisconsin.,Department of Physiology, Medical College of Wisconsin , Milwaukee, Wisconsin
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Ghaddhab C, Vuissoz JM, Deladoëy J. From Bioinactive ACTH to ACTH Antagonist: The Clinical Perspective. Front Endocrinol (Lausanne) 2017; 8:17. [PMID: 28228747 PMCID: PMC5296294 DOI: 10.3389/fendo.2017.00017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/18/2017] [Indexed: 12/11/2022] Open
Abstract
The adrenocorticotropic hormone (ACTH) is a pituitary hormone derived from a larger peptide, the proopiomelanocortin (POMC), as are the MSHs (α-MSH, β-MSH, and γ-MSH) and the β-LPH-related polypeptides (Figure 1A). ACTH drives adrenal steroidogenesis and growth of the adrenal gland. ACTH is a 39 amino acid polypeptide that binds and activates its cognate receptor [melanocortin receptor 2 (MC2R)] through the two regions H6F7R8W9 and K15K16R17R18P19. Most POMC-derived polypeptides contain the H6F7R8W9 sequence that is conserved through evolution. This explains the difficulties in developing selective agonists or antagonists to the MCRs. In this review, we will discuss the clinical aspects of the role of ACTH in physiology and disease, and potential clinical use of selective ACTH antagonists.
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Affiliation(s)
- Chiraz Ghaddhab
- Endocrinology Service and Research Center, Sainte-Justine University Hospital Center, Department of Pediatrics, Université de Montréal, Montreal, QC, Canada
| | - Jean-Marc Vuissoz
- Division of Pediatric Endocrinology, University Children’s Hospital Basel (UKBB), University of Basel, Basel, Switzerland
| | - Johnny Deladoëy
- Endocrinology Service and Research Center, Sainte-Justine University Hospital Center, Department of Pediatrics, Université de Montréal, Montreal, QC, Canada
- *Correspondence: Johnny Deladoëy,
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Ciato D, Mumbach AG, Paez-Pereda M, Stalla GK. Currently used and investigational drugs for Cushing´s disease. Expert Opin Investig Drugs 2016; 26:75-84. [PMID: 27894193 DOI: 10.1080/13543784.2017.1266338] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Cushing's disease (CD) is caused by a corticotroph adenoma of the pituitary gland that secretes excess adrenocorticotropic hormone (ACTH) causing increased morbidity and mortality. Surgery is the treatment of choice, but is not always successful. Alternatives include radiotherapy, adrenal surgery, and pharmaceutical therapy. The latter is increasingly gaining momentum due to the recent development of compounds that reduce hypercortisolaemia or its symptoms, acting through different mechanisms. Areas covered: In this article, the authors provide a complete overview of the treatment options for Cushing´s disease, including adrenal-directed, tumor-targeted, and peripheral therapies that are currently used or in development, and discuss their potential advantages and limitations. Expert opinion: Considering the lack of long-term remission in up to half of the patients after surgery, and the delayed response to radiotherapy along with potential side effects, there is a strong need for an effective pharmaceutical treatment. Pasireotide, mifepristone, ketoconazole and metyrapone have been approved by regulatory authorities but their use remains limited due to considerable costs and side effects. Research in this field has focused recently on the improvement of pre-existing drugs and the development of safe new ones. However, few approaches aim at targeting the source of the disease, the ACTH-secreting adenoma.
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Affiliation(s)
- Denis Ciato
- a Clinical Neuroendocrinology , Max Planck Institute of Psychiatry , Munich , Germany.,b Endocrinology Division, Department of Medicine , University-Hospital of Padua , Padua , Italy
| | - Aizhar G Mumbach
- c Endocrinology Division , Carlos G. Durand Hospital , Buenos Aires , Argentina
| | - Marcelo Paez-Pereda
- a Clinical Neuroendocrinology , Max Planck Institute of Psychiatry , Munich , Germany
| | - Günter K Stalla
- a Clinical Neuroendocrinology , Max Planck Institute of Psychiatry , Munich , Germany
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Clark AJ, Forfar R, Hussain M, Jerman J, McIver E, Taylor D, Chan L. ACTH Antagonists. Front Endocrinol (Lausanne) 2016; 7:101. [PMID: 27547198 PMCID: PMC4974254 DOI: 10.3389/fendo.2016.00101] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/08/2016] [Indexed: 12/28/2022] Open
Abstract
Adrenocorticotropin (ACTH) acts via a highly selective receptor that is a member of the melanocortin receptor subfamily of type 1 G protein-coupled receptors. The ACTH receptor, also known as the melanocortin 2 receptor (MC2R), is unusual in that it is absolutely dependent on a small accessory protein, melanocortin receptor accessory protein (MRAP) for cell surface expression and function. ACTH is the only known naturally occurring agonist for this receptor. This lack of redundancy and high degree of ligand specificity suggests that antagonism of this receptor could provide a useful therapeutic aid and a potential investigational tool. Clinical situations in which this could be useful include (1) Cushing's disease and ectopic ACTH syndrome - especially while preparing for definitive treatment of a causative tumor, or in refractory cases, or (2) congenital adrenal hyperplasia - as an adjunct to glucocorticoid replacement. A case for antagonism in other clinical situations in which there is ACTH excess can also be made. In this article, we will explore the scientific and clinical case for an ACTH antagonist, and will review the evidence for existing and recently described peptides and modified peptides in this role.
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Affiliation(s)
- Adrian John Clark
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Rachel Forfar
- Centre for Therapeutics Discovery, MRC Technology, Stevenage, UK
| | - Mashal Hussain
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Jeff Jerman
- Centre for Therapeutics Discovery, MRC Technology, Stevenage, UK
| | - Ed McIver
- Centre for Therapeutics Discovery, MRC Technology, Stevenage, UK
| | - Debra Taylor
- Centre for Therapeutics Discovery, MRC Technology, Stevenage, UK
| | - Li Chan
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, London, UK
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17
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Nensey NK, Bodager J, Gehrand AL, Raff H. Effect of Novel Melanocortin Type 2 Receptor Antagonists on the Corticosterone Response to ACTH in the Neonatal Rat Adrenal Gland In Vivo and In Vitro. Front Endocrinol (Lausanne) 2016; 7:23. [PMID: 27047449 PMCID: PMC4800183 DOI: 10.3389/fendo.2016.00023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
Stress-induced increases in neonatal corticosterone demonstrate a unique shift from ACTH independence to ACTH dependence between postnatal day 2 (PD2) and day 8 (PD8) in newborn rats. This shift could be due to the binding of a bioactive, non--immunoreactive plasma ligand to the adrenocortical melanocortin 2 receptor (MC2R) (ACTH receptor). A potent MC2R antagonist would be useful to evaluate this phenomenon in the neonate. Therefore, we investigated the acute corticosterone response to ACTH(1-39) injection in rat pups pretreated with newly developed MC2R antagonists (GPS1573 and GPS1574), which have not been tested in vivo. The doses used in vivo were based on their in vitro potency, with GP1573 being more potent than GPS1574. GPS1573 (PD2 and PD8), GPS1574 (PD2 only), or vehicle were injected intraperitoneally (ip) 10 min before baseline sampling. Then, 0.001 mg/kg of ACTH(1-39) was injected ip, and subsequent blood samples obtained for the measurement of plasma corticosterone. Pretreatment of PD2 pups with GPS1573 demonstrated augmentation, rather than inhibition, of the corticosterone response to ACTH. In PD8 pups, pretreatment with 0.1 mg/kg GPS1573, but not 4 mg/kg, augmented the corticosterone response to ACTH. Pretreatment with GPS1574 attenuated the plasma corticosterone response to ACTH at 30 min in PD2 pups. The activity of these two compounds in vivo do not match their potency in vitro, with GPS1573 leading to a small augmentation of the corticosterone response to ACTH in vivo while GPS1574 resulted in inhibition.
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Affiliation(s)
- Nasha K. Nensey
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
- Endocrine Research Laboratory, Aurora St. Luke’s Medical Center, Aurora Research Institute, Milwaukee, WI, USA
| | - Jonathan Bodager
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
- Endocrine Research Laboratory, Aurora St. Luke’s Medical Center, Aurora Research Institute, Milwaukee, WI, USA
| | - Ashley L. Gehrand
- Endocrine Research Laboratory, Aurora St. Luke’s Medical Center, Aurora Research Institute, Milwaukee, WI, USA
| | - Hershel Raff
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
- Endocrine Research Laboratory, Aurora St. Luke’s Medical Center, Aurora Research Institute, Milwaukee, WI, USA
- *Correspondence: Hershel Raff,
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19
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Jackson DS, Ramachandrappa S, Clark AJ, Chan LF. Melanocortin receptor accessory proteins in adrenal disease and obesity. Front Neurosci 2015; 9:213. [PMID: 26113808 PMCID: PMC4461818 DOI: 10.3389/fnins.2015.00213] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/28/2015] [Indexed: 12/02/2022] Open
Abstract
Melanocortin receptor accessory proteins (MRAPs) are regulators of the melanocortin receptor family. MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency type 2. The role of its paralog melanocortin-2-receptor accessory protein 2 (MRAP2), which is predominantly expressed in the hypothalamus including the paraventricular nucleus, has recently been linked to mammalian obesity. Whole body deletion and targeted brain specific deletion of the Mrap2 gene result in severe obesity in mice. Interestingly, Mrap2 complete knockout (KO) mice have increased body weight without detectable changes to food intake or energy expenditure. Rare heterozygous variants of MRAP2 have been found in humans with severe, early-onset obesity. In vitro data have shown that Mrap2 interaction with the melanocortin-4-receptor (Mc4r) affects receptor signaling. However, the mechanism by which Mrap2 regulates body weight in vivo is not fully understood and differences between the phenotypes of Mrap2 and Mc4r KO mice may point toward Mc4r independent mechanisms.
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Affiliation(s)
- David S Jackson
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London London, UK
| | - Shwetha Ramachandrappa
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London London, UK
| | - Adrian J Clark
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London London, UK
| | - Li F Chan
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London London, UK
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