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Guo X, Wen J, Gao Q, Zhao Y, Zhao Y, Wang C, Xu N, Shao Y, Chang X. Orexin-A/OX1R is involved in regulation of autophagy to promote cortisol secretion in adrenocortical cell. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166844. [PMID: 37572990 DOI: 10.1016/j.bbadis.2023.166844] [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: 02/24/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 08/14/2023]
Abstract
BACKGROUND Hypercortisolism has emerged as a prominent clinical condition worldwide caused by biochemical cortisol excess in patients, and optimization treatment is needed urgently in the clinic. Previously, we observed that orexin-A/orexin type 1 receptor (OX1R) promoted cell proliferation, inhibited apoptosis, and increased cortisol release in adrenocortical cells. However, the functions of orexin-A/OX1R on autophagy and its molecular mechanism are not known. METHODS Transmission electron microscopy and confocal microscope were performed to detect autophagosomes. Western blot were performed to detect autophagy proteins. The cortisol concentration was assessed with an ELISA. FINDINGS Our data demonstrated that orexin-A/OX1R activated the mammalian target of rapamycin/p70 ribosomal protein S6 kinase-1 pathway, thereby inhibiting autophagy in H295R cells and Y-1 cells. Furthermore, the orexin-A/OX1R-mediated suppression of autophagy played a crucial role in cortisol secretion. Mechanistically, the expression of 3β-hydroxysteroid dehydrogenase/isomerase, the rate-limiting enzyme in cortisol synthesis, was increased with autophagy inhibition mediated by orexin-A/OX1R. INTERPRETATION This study provided the evidence that orexin-A/OX1R participated in modulating mTOR/p70S6K1/autophagy signaling pathway to promote cortisol secretion in adrenocortical cell. The findings suggest the mechanistic basis for disorders of cortisol secretion, providing the potential therapeutic targets for hypercortisolism treatment. FUND: This work was supported by National Natural Science Foundation of China (32170603, 31871286), the Doctoral Start-up Foundation of Liaoning Province (20180540008, 2019-BS-298), the Natural Science Foundation of Liaoning Province (2019-ZD-0779), and Shenyang Science and Technology Plan Fund Projects (21-173-9-28).
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Affiliation(s)
- Xin Guo
- Department of Pediatrics, The Fourth Affiliated Hospital, China Medical University, Shenyang, Liaoning 110001, PR China
| | - Jing Wen
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital, China Medical University, Shenyang, Liaoning 110001, PR China
| | - Qianqian Gao
- Department of the First Obstetric Ward, Wei Fang People's Hospital, Weifang, Shandong 261041, PR China
| | - Yuyan Zhao
- Department of Endocrinology and Metabolism, The First Affiliated Hospital, China Medical University, Shenyang, Liaoning 110032, PR China
| | - Yue Zhao
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang, Liaoning 110122, PR China
| | - Chunyu Wang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang, Liaoning 110122, PR China
| | - Na Xu
- Natural Sciences Department, LaGuardia Community College (City University of New York), 31-10 Thomson Ave, Long Island City, NY 11101, USA
| | - Yaozhong Shao
- The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shanxi 710061, PR China
| | - Xiaocen Chang
- Department of Endocrinology and Metabolism, The Fourth Affiliated Hospital, China Medical University, Shenyang, Liaoning 110001, PR China.
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2
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Blais A, Lan A, Blachier F, Benamouzig R, Jouet P, Couvineau A. Efficiency of Orexin-A for Inflammatory Flare and Mucosal Healing in Experimental Colitis: Comparison with the Anti-TNF Alpha Infliximab. Int J Mol Sci 2023; 24:ijms24119554. [PMID: 37298505 DOI: 10.3390/ijms24119554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Inflammatory bowel diseases are chronic inflammation of the intestinal mucosa characterized by relapsing-remitting cycle periods of variable duration. Infliximab (IFX) was the first monoclonal antibody used for the treatment of Crohn's disease and ulcerative colitis (UC). High variability between treated patients and loss of IFX efficiency over time support the further development of drug therapy. An innovative approach has been suggested based on the presence of orexin receptor (OX1R) in the inflamed human epithelium of UC patients. In that context, the aim of this study was to compare, in a mouse model of chemically induced colitis, the efficacy of IFX compared to the hypothalamic peptide orexin-A (OxA). C57BL/6 mice received 3.5% dextran sodium sulfate (DSS) in drinking water for 5 days. Since the inflammatory flare was maximal at day 7, IFX or OxA was administered based on a curative perspective at that time for 4 days using intraperitoneal injection. Treatment with OxA promoted mucosal healing and decreased colonic myeloperoxidase activity, circulating concentrations of lipopolysaccharide-binding protein, IL-6 and tumor necrosis factor alpha (TNFα) and decreased expression of genes encoding cytokines in colonic tissues with better efficacy than IFX allowing for more rapid re-epithelization. This study demonstrates the comparable anti-inflammatory properties of OxA and IFX and shows that OxA is efficient in promoting mucosal healing, suggesting that OxA treatment is a promising new biotherapy.
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Affiliation(s)
- Anne Blais
- UMR-PNCA, Université Paris-Saclay, AgroParisTech, INRAE, 91120 Palaiseau, France
| | - Annaïg Lan
- UMR-PNCA, Université Paris-Saclay, AgroParisTech, INRAE, 91120 Palaiseau, France
| | - François Blachier
- UMR-PNCA, Université Paris-Saclay, AgroParisTech, INRAE, 91120 Palaiseau, France
| | - Robert Benamouzig
- UMR-PNCA, Université Paris-Saclay, AgroParisTech, INRAE, 91120 Palaiseau, France
- Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, 93000 Bobigny, France
| | - Pauline Jouet
- Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, 93000 Bobigny, France
| | - Alain Couvineau
- INSERM UMR 1149/Centre de Recherche sur l'Inflammation (CRI), Faculté de Médecine X. Bichat, Université Paris Cité, 75018 Paris, France
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3
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Ten-Blanco M, Flores Á, Cristino L, Pereda-Pérez I, Berrendero F. Targeting the orexin/hypocretin system for the treatment of neuropsychiatric and neurodegenerative diseases: from animal to clinical studies. Front Neuroendocrinol 2023; 69:101066. [PMID: 37015302 DOI: 10.1016/j.yfrne.2023.101066] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/15/2023] [Accepted: 03/30/2023] [Indexed: 04/06/2023]
Abstract
Orexins (also known as hypocretins) are neuropeptides located exclusively in hypothalamic neurons that have extensive projections throughout the central nervous system and bind two different G protein-coupled receptors (OX1R and OX2R). Since its discovery in 1998, the orexin system has gained the interest of the scientific community as a potential therapeutic target for the treatment of different pathological conditions. Considering previous basic science research, a dual orexin receptor antagonist, suvorexant, was the first orexin agent to be approved by the US Food and Drug Administration to treat insomnia. In this review, we discuss and update the main preclinical and human studies involving the orexin system with several psychiatric and neurodegenerative diseases. This system constitutes a nice example of how basic scientific research driven by curiosity can be the best route to the generation of new and powerful pharmacological treatments.
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Affiliation(s)
- Marc Ten-Blanco
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - África Flores
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Neurosciences Institute, University of Barcelona and Bellvitge University Hospital-IDIBELL, 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry (ICB), National Research Council (CNR), Pozzuoli, Italy
| | - Inmaculada Pereda-Pérez
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Fernando Berrendero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Madrid, Spain.
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4
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Dale NC, Hoyer D, Jacobson LH, Pfleger KDG, Johnstone EKM. Orexin Signaling: A Complex, Multifaceted Process. Front Cell Neurosci 2022; 16:812359. [PMID: 35496914 PMCID: PMC9044999 DOI: 10.3389/fncel.2022.812359] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/07/2022] [Indexed: 11/15/2022] Open
Abstract
The orexin system comprises two G protein-coupled receptors, OX1 and OX2 receptors (OX1R and OX2R, respectively), along with two endogenous agonists cleaved from a common precursor (prepro-orexin), orexin-A (OX-A) and orexin-B (OX-B). For the receptors, a complex array of signaling behaviors has been reported. In particular, it becomes obvious that orexin receptor coupling is very diverse and can be tissue-, cell- and context-dependent. Here, the early signal transduction interactions of the orexin receptors will be discussed in depth, with particular emphasis on the direct G protein interactions of each receptor. In doing so, it is evident that ligands, additional receptor-protein interactions and cellular environment all play important roles in the G protein coupling profiles of the orexin receptors. This has potential implications for our understanding of the orexin system’s function in vivo in both central and peripheral environments, as well as the development of novel agonists, antagonists and possibly allosteric modulators targeting the orexin system.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Laura H. Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Kevin D. G. Pfleger,
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- Elizabeth K. M. Johnstone,
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5
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Madaan P, Behl T, Sehgal A, Singh S, Sharma N, Yadav S, Kaur S, Bhatia S, Al-Harrasi A, Abdellatif AAH, Ashraf GM, Abdel-Daim MM, Dailah HG, Anwer MK, Bungau S. Exploring the Therapeutic Potential of Targeting Purinergic and Orexinergic Receptors in Alcoholic Neuropathy. Neurotox Res 2022; 40:646-669. [DOI: 10.1007/s12640-022-00477-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 12/11/2022]
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Coleman P, de Lecea L, Gotter A, Hagan J, Hoyer D, Kilduff T, Kukkonen JP, Porter R, Renger J, Siegel JM, Sutcliffe G, Upton N, Winrow CJ. Orexin receptors in GtoPdb v.2021.3. IUPHAR/BPS GUIDE TO PHARMACOLOGY CITE 2021; 2021. [PMID: 34927075 DOI: 10.2218/gtopdb/f51/2021.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Orexin receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Orexin receptors [42]) are activated by the endogenous polypeptides orexin-A and orexin-B (also known as hypocretin-1 and -2; 33 and 28 aa) derived from a common precursor, preproorexin or orexin precursor, by proteolytic cleavage and some typical peptide modifications [109]. Currently the only orexin receptor ligands in clinical use are suvorexant and lemborexant, which are used as hypnotics. Orexin receptor crystal structures have been solved [134, 133, 54, 117, 46].
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Fan Y, Jiang E, Gao H, Bigalke J, Chen B, Yu C, Chen Q, Shan Z. Activation of Orexin System Stimulates CaMKII Expression. Front Physiol 2021; 12:698185. [PMID: 34276418 PMCID: PMC8282234 DOI: 10.3389/fphys.2021.698185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/08/2021] [Indexed: 11/18/2022] Open
Abstract
Hyperactivity of the orexin system within the paraventricular nucleus (PVN) has been shown to contribute to increased sympathetic nerve activity (SNA) and blood pressure (BP) in rodent animals. However, the underlying molecular mechanisms remain unclear. Here, we test the hypothesis that orexin system activation stimulates calcium/calmodulin-dependent kinase II (CaMKII) expression and activation, and stimulation of CaMKII expressing PVN neurons increases SNA and BP. Real-time PCR and/or western blot were carried out to test the effect of orexin-A administration on CaMKII expression in the PVN of normal Sprague Dawley (SD) rats and orexin receptor 1 (OX1R) expressing PC12 cells. Immunostaining was performed to assess OX1R cellular localization in the PVN of SD rats as well as orexin-A treatment on CaMKII activation in cultured hypothalamic neurons. In vivo sympathetic nerve recordings were employed to test the impact of optogenetic stimulation of CaMKII-expressing PVN neurons on the renal SNA (RSNA) and BP. The results showed that intracerebroventricular injection of orexin-A into the SD rat increases mRNA expression of CaMKII subunits in the PVN. In addition, Orexin-A treatment increases CaMKII expression and its phosphorylation in OX1R-expressing PC12 cells. Furthermore, Orexin-A treatment increases CaMKII activation in cultured hypothalamic neurons from neonatal SD rats. Finally, optogenetic excitation of PVN CaMKII-expressing neurons results in robust increases in RSNA and BP in SD rats. Our results suggest that increased orexin system activity activates CaMKII expression in cardiovascular relevant regions, and this may be relevant to the downstream cardiovascular effects of CaMKII.
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Affiliation(s)
- Yuanyuan Fan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,School of Life Sciences, Henan University, Kaifeng, China
| | - Enshe Jiang
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Institute of Nursing and Health, Henan University, Kaifeng, China
| | - Huanjia Gao
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,The Second Clinical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jeremy Bigalke
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Bojun Chen
- Department of Emergency, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Chunxiu Yu
- Health Research Institute, Michigan Technological University, Houghton, MI, United States.,Department of Biological Sciences, Michigan Technological University, Houghton, MI, United States
| | - Qinghui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
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8
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Synchronous neuronal interactions in rat hypothalamic culture: a novel model for the study of network dynamics in metabolic disorders. Exp Brain Res 2021; 239:755-764. [PMID: 33388905 DOI: 10.1007/s00221-020-05977-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/29/2020] [Indexed: 12/23/2022]
Abstract
Synchronous neural activity is a feature of normal brain function, and altered synchronization is observed in several neurological diseases. Dysfunction in hypothalamic pathways leads to obesity, suggesting that hypothalamic neural synchrony is critical for energy homeostasis. The lateral hypothalamic orexin neurons are extensively interconnected with other brain structures and are important for energy balance. Earlier studies show that rats with higher orexin sensitivity are obesity resistant. Similarly, topiramate, an anti-epileptic drug, has been shown to reduce weight in humans. Since orexin enhances neuronal excitation, we hypothesized that obesity-resistant rats with higher orexin sensitivity may exhibit enhanced hypothalamic synchronization. We further hypothesized that anti-obesity agents such as orexin and topiramate will enhance hypothalamic synchronization. To test this, we examined neural synchronicity in primary embryonic hypothalamic cell cultures, obtained from embryonic day 18 (E18) obesity-susceptible Sprague-Dawley (SD) and obesity-resistant rats. Hypothalamic tissue was cultured in multielectrode array (MEA), and recordings were performed twice weekly, from 4th to 32nd day in vitro (DIV). Next, we tested the effects of orexin and topiramate application on neural synchronicity of hypothalamic cultures obtained from SD rat embryos. Signals were analyzed for synchronization using cross correlation. Our results showed that (1) obesity-resistant hypothalamus exhibits significantly higher synchronization compared to obesity-sensitive hypothalamus; and (2) orexin and topiramate enhance hypothalamic synchronization. These results support that enhanced orexin sensitivity is associated with greater neural synchronization, and that anti-obesity treatments enhance network synchronization, thus constrain variability in hypothalamic output signals, to extrahypothalamic structures involved in energy homeostasis.
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9
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Allosteric interactions via the orthosteric ligand binding sites in a constitutive G-protein-coupled receptor homodimer. Pharmacol Res 2020; 166:105116. [PMID: 32783977 DOI: 10.1016/j.phrs.2020.105116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 11/23/2022]
Abstract
I interpret some recent data to indicate that co-operative effects take place between the (identical) orthosteric binding sites in a G-protein-coupled receptor dimer. In the current study, the reasonability of this concept was tested by creating a mathematical model. The model is composed of a symmetrical constitutive receptor dimer in which the protomers are able to affect each other allosterically, and it includes binding, receptor activation and signal amplification steps. The model was utilized for analyses of previous data as well as simulations of predicted behaviour. The model demonstrates the behaviour stated in the hypotheses, i.e. even an apparently neutral receptor ligand can allosterically affect agonist binding or receptor activation by binding to the normal orthosteric ligand binding site. Therewith the speculated allosteric action originating from the orthosteric binding site of the dimeric receptor is a realistic possibility. The results of the simulations and curve fitting constitute a reasonable starting point for further studies, and the model can be utilized to design meaningful experiments to investigate these questions.
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10
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Turku A, Leino TO, Karhu L, Yli-Kauhaluoma J, Kukkonen JP, Wallén EAA, Xhaard H. Structure-Activity Relationships of 1-Benzoylazulenes at the OX 1 and OX 2 Orexin Receptors. ChemMedChem 2019; 14:965-981. [PMID: 30892823 DOI: 10.1002/cmdc.201900074] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/20/2019] [Indexed: 11/08/2022]
Abstract
We previously demonstrated the potential of di- or trisubstituted azulenes as ligands (potentiators, weak agonists, and antagonists) of the orexin receptors. In this study we investigated 27 1-benzoylazulene derivatives, uncovering seven potentiators of the orexin response on OX1 and two weak dual orexin receptor agonists. For potentiators, replacement of the azulene scaffold by indole retained the activity of four out of six compounds. The structure-activity relationships for agonism and potentiation can be summarized into a bicyclic aromatic ring system substituted with two hydrogen-bond acceptors (1-position, benzoyl; 6-position, carboxyl/ester) within 7-8 Å of each other; a third acceptor at the 3-position is also well tolerated. The same pharmacophoric signature is found in the preferred conformations of the orexin receptor agonist Nag26 from molecular dynamics simulations. Subtle changes switch the activity between weak agonism and potentiation, suggesting overlapping binding sites.
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Affiliation(s)
- Ainoleena Turku
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.,Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014, Helsinki, Finland
| | - Teppo O Leino
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Lasse Karhu
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Jari Yli-Kauhaluoma
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Jyrki P Kukkonen
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014, Helsinki, Finland.,Department of Physiology, Faculty of Medicine, University of Helsinki, P.O. Box 63, 00014, Helsinki, Finland
| | - Erik A A Wallén
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Henri Xhaard
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
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11
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Leino TO, Turku A, Yli-Kauhaluoma J, Kukkonen JP, Xhaard H, Wallén EA. Azulene-based compounds for targeting orexin receptors. Eur J Med Chem 2018; 157:88-100. [DOI: 10.1016/j.ejmech.2018.07.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 06/29/2018] [Accepted: 07/15/2018] [Indexed: 01/08/2023]
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Abstract
Purpose of Review The aim of this review was to summarize collected data on the role of orexin and orexin neurons in the control of sleep and blood pressure. Recent Findings Although orexins (hypocretins) have been known for only 20 years, an impressive amount of data is now available regarding their physiological role. Hypothalamic orexin neurons are responsible for the control of food intake and energy expenditure, motivation, circadian rhythm of sleep and wake, memory, cognitive functions, and the cardiovascular system. Multiple studies show that orexinergic stimulation results in increased blood pressure and heart rate and that this effect may be efficiently attenuated by orexinergic antagonism. Increased activity of orexinergic neurons is also observed in animal models of hypertension. Summary Pharmacological intervention in the orexinergic system is now one of the therapeutic possibilities in insomnia. Although the role of orexin in the control of blood pressure is well described, we are still lacking clinical evidence that this is a possibility for a new approach in the treatment of cardiovascular diseases.
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Affiliation(s)
- Mariusz Sieminski
- Department of Emergency Medicine, Medical University of Gdansk, Smoluchowskiego 17, 80-235, Gdansk, Poland.
| | - Jacek Szypenbejl
- Department of Emergency Medicine, Medical University of Gdansk, Smoluchowskiego 17, 80-235, Gdansk, Poland
| | - Eemil Partinen
- Department of Neurology, University of Helsinki, Helsinki, Finland
- Vitalmed Helsinki Sleep Clinic, Helsinki, Finland
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13
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Karhu L, Weisell J, Turunen PM, Leino TO, Pätsi H, Xhaard H, Kukkonen JP, Wallén EAA. Stapled truncated orexin peptides as orexin receptor agonists. Peptides 2018; 102:54-60. [PMID: 29475074 DOI: 10.1016/j.peptides.2018.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/29/2018] [Accepted: 02/16/2018] [Indexed: 10/18/2022]
Abstract
The peptides orexin-A and -B, the endogenous agonists of the orexin receptors, have similar 19-amino-acid C-termini which retain full maximum response as truncated peptides with only marginally reduced potency, while further N-terminal truncations successively reduce the activity. The peptides have been suggested to bind in an α-helical conformation, and truncation beyond a certain critical length is likely to disrupt the overall helical structure. In this study, we set out to stabilize the α-helical conformation of orexin-A15-33 via peptide stapling at four different sites. At a suggested hinge region, we varied the length of the cross-linker as well as replaced the staple with two α-aminoisobutyric acid residues. Modifications close to the peptide C-terminus, which is crucial for activity, were not allowed. However, central and N-terminal modifications yielded bioactive peptides, albeit with decreased potencies. This provides evidence that the orexin receptors can accommodate and be activated by α-helical peptides. The decrease in potency is likely linked to a stabilization of suboptimal peptide conformation or blocking of peptide backbone-receptor interactions at the hinge region by the helical stabilization or the modified amino acids.
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Affiliation(s)
- Lasse Karhu
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, POB 56, FI-00014 University of Helsinki, Finland.
| | - Janne Weisell
- School of Pharmacy, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland.
| | - Pauli M Turunen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, Faculty of Veterinary Medicine, POB 66, FI-00014, University of Helsinki, Finland; Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, POB 63, FI-00014 University of Helsinki, Finland.
| | - Teppo O Leino
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, POB 56, FI-00014 University of Helsinki, Finland.
| | - Henri Pätsi
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, POB 56, FI-00014 University of Helsinki, Finland.
| | - Henri Xhaard
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, POB 56, FI-00014 University of Helsinki, Finland.
| | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, Faculty of Veterinary Medicine, POB 66, FI-00014, University of Helsinki, Finland; Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, POB 63, FI-00014 University of Helsinki, Finland.
| | - Erik A A Wallén
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, POB 56, FI-00014 University of Helsinki, Finland.
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Abstract
Orexin/hypocretin peptide (orexin-A and orexin-B) signaling is believed to take place via the two G-protein-coupled receptors (GPCRs), named OX1 and OX2 orexin receptors, as described in the previous chapters. Signaling of orexin peptides has been investigated in diverse endogenously orexin receptor-expressing cells - mainly neurons but also other types of cells - and in recombinant cells expressing the receptors in a heterologous manner. Findings in the different systems are partially convergent but also indicate cellular background-specific signaling. The general picture suggests an inherently high degree of diversity in orexin receptor signaling.In the current chapter, I present orexin signaling on the cellular and molecular levels. Discussion of the connection to (potential) physiological orexin responses is only brief since these are in focus of other chapters in this book. The same goes for the post-synaptic signaling mechanisms, which are dealt with in Burdakov: Postsynaptic actions of orexin. The current chapter is organized according to the tissue type, starting from the central nervous system. Finally, receptor signaling pathways are discussed across tissues, cell types, and even species.
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Affiliation(s)
- Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, POB 66, FIN-00014, Helsinki, Finland.
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15
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Dynamics of ligand binding to GPCR: Residence time of melanocortins and its modulation. Pharmacol Res 2016; 113:747-753. [DOI: 10.1016/j.phrs.2016.05.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 05/22/2016] [Accepted: 05/27/2016] [Indexed: 01/06/2023]
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16
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Turku A, Borrel A, Leino TO, Karhu L, Kukkonen JP, Xhaard H. Pharmacophore Model To Discover OX1 and OX2 Orexin Receptor Ligands. J Med Chem 2016; 59:8263-75. [DOI: 10.1021/acs.jmedchem.6b00333] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Ainoleena Turku
- Faculty of Pharmacy,
Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
- Faculty of Veterinary Medicine, Department of Veterinary Biosciences, University of Helsinki, P.O. Box 66, FIN-00014 Helsinki, Finland
| | - Alexandre Borrel
- Faculty of Pharmacy,
Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
| | - Teppo O. Leino
- Faculty of Pharmacy,
Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
| | - Lasse Karhu
- Faculty of Pharmacy,
Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
| | - Jyrki P. Kukkonen
- Faculty of Veterinary Medicine, Department of Veterinary Biosciences, University of Helsinki, P.O. Box 66, FIN-00014 Helsinki, Finland
| | - Henri Xhaard
- Faculty of Pharmacy,
Division of Pharmaceutical Chemistry and Technology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
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17
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Imperatore R, Palomba L, Morello G, Spiezio AD, Piscitelli F, Marzo VD, Cristino L. Formation of OX-1R/CB 1 R heteromeric complexes in embryonic mouse hypothalamic cells: Effect on intracellular calcium, 2-arachidonoyl-glycerol biosynthesis and ERK phosphorylation. Pharmacol Res 2016; 111:600-609. [DOI: 10.1016/j.phrs.2016.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/27/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022]
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18
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Kukkonen JP. G-protein-dependency of orexin/hypocretin receptor signalling in recombinant Chinese hamster ovary cells. Biochem Biophys Res Commun 2016; 476:379-385. [PMID: 27237973 DOI: 10.1016/j.bbrc.2016.05.130] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 05/25/2016] [Indexed: 01/07/2023]
Abstract
Multiple signalling pathways for orexin receptors have been discovered, and most thoroughly mapped in Chinese hamster ovary K1 (CHO-K1) cells. It is also known that orexin receptors can couple to the G-protein families Gi, Gs and Gq. However, the connection between the G-proteins and the downstream signals is only vaguely established, and we now set out to resolve this for human orexin receptors expressed in CHO-K1 cells. Adenylyl cyclase (AC), phospholipase A2, C and D, and diacylglycerol lipase activities were assessed by precursor radiolabelling and chromatographic separation, and calcium by fluorescent methods. Pertussis toxin, cholera toxin and the cyclic depsipeptide, UBO-QIC a.k.a. FR900359, were used to assess the involvement of Gi-, Gs- and Gq-family G-proteins, respectively. Calcium elevations as well as activation of the phospholipases and diacylglycerol lipase were dependent on Gq, as they were fully blocked by UBO-QIC. The low-potency AC activation fully depended on Gs. Surprisingly, the assumed Gi-dependent inhibition of AC was (fully or partially) inhibited by UBO-QIC, in opposition to the previous findings of no sensitivity of Gi proteins to UBO-QIC. Orexin receptor signalling is indeed mostly Gq-driven in CHO-K1 cells, even with respect to the less clearly mapped cascades such as phospholipase A2 and C and calcium influx, underlining the importance of Gq even under physiological conditions. AC regulation warrants more studies.
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Affiliation(s)
- Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, POB 66, FIN-00014, University of Helsinki, Helsinki, Finland.
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19
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Lu GL, Lee CH, Chiou LC. Orexin A induces bidirectional modulation of synaptic plasticity: Inhibiting long-term potentiation and preventing depotentiation. Neuropharmacology 2016; 107:168-180. [PMID: 26965217 DOI: 10.1016/j.neuropharm.2016.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/19/2016] [Accepted: 03/01/2016] [Indexed: 01/30/2023]
Abstract
The orexin system consists of two peptides, orexin A and B and two receptors, OX1R and OX2R. It is implicated in learning and memory regulation while controversy remains on its role in modulating hippocampal synaptic plasticity in vivo and in vitro. Here, we investigated effects of orexin A on two forms of synaptic plasticity, long-term potentiation (LTP) and depotentiation of field excitatory postsynaptic potentials (fEPSPs), at the Schaffer Collateral-CA1 synapse of mouse hippocampal slices. Orexin A (≧30 nM) attenuated LTP induced by theta burst stimulation (TBS) in a manner antagonized by an OX1R (SB-334867), but not OX2R (EMPA), antagonist. Conversely, at 1 pM, co-application of orexin A prevented the induction of depotentiation induced by low frequency stimulation (LFS), i.e. restoring LTP. This re-potentiation effect of sub-nanomolar orexin A occurred at LFS of 1 Hz, but not 2 Hz, and with LTP induced by either TBS or tetanic stimulation. It was significantly antagonized by SB-334867, EMPA and TCS-1102, selective OX1R, OX2R and dual OXR antagonists, respectively, and prevented by D609, SQ22536 and H89, inhibitors of phospholipase C (PLC), adenylyl cyclase (AC) and protein kinase A (PKA), respectively. LFS-induced depotentiation was antagonized by blockers of NMDA, A1-adenosine and type 1/5 metabotropic glutamate (mGlu1/5) receptors, respectively. However, orexin A (1 pM) did not affect chemical-induced depotentiation by agonists of these receptors. These results suggest that orexin A bidirectionally modulates hippocampal CA1 synaptic plasticity, inhibiting LTP via OX1Rs at moderate concentrations while inducing re-potentiation via OX1Rs and OX2Rs, possibly through PLC and AC-PKA signaling at sub-nanomolar concentrations.
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Affiliation(s)
- Guan-Ling Lu
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Hsu Lee
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Lih-Chu Chiou
- Graduate Institute and College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Reserach Center for Chinese Medicine & Acupuncture, China Medical University, Taichung, Taiwan.
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20
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G-protein inhibition profile of the reported Gq/11 inhibitor UBO-QIC. Biochem Biophys Res Commun 2015; 469:101-107. [PMID: 26614908 DOI: 10.1016/j.bbrc.2015.11.078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 11/18/2015] [Indexed: 11/22/2022]
Abstract
UBO-QIC (FR900359) is the only currently available Gq/11 protein inhibitor. However, its characterization has not been published, and we thus set out to do this. Gi, Gs and Gq protein-mediated responses were assessed utilizing endogenous or heterologously expressed receptors in Chinese hamster ovary cells. UBO-QIC, at 1 μM, was an effective inhibitor of the Gq-mediated responses, but was inactive at Gi- and Gs-mediated responses. Gq/11 and G16 responses were additionally compared in HEL92.1.7 cells, showing inhibition of Gq/11 responses. However, UBO-QIC also appeared to inhibit G16. Further studies are required to establish its profile with respect to the different Gq-family proteins.
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21
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OX2 orexin/hypocretin receptor signal transduction in recombinant Chinese hamster ovary cells. Cell Signal 2015; 28:51-60. [PMID: 26582739 DOI: 10.1016/j.cellsig.2015.11.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/30/2015] [Accepted: 11/10/2015] [Indexed: 01/06/2023]
Abstract
There are two subtypes of orexin receptors, OX1 and OX2. Signalling pathways have been mapped in much higher detail for OX1 receptors than OX2 receptors. Almost all the detailed studies have been performed in Chinese hamster ovary cells, and we thus chose the same cell background for the studies on human OX2 receptors to allow comparison to human OX1 receptors. Adenylyl cyclase, phospholipase A2, C and D and diacylglycerol lipase activities were assessed by precursor radiolabelling and chromatographic separation (ion exchange, affinity or thin layer), calcium by a fluorescent method, and receptor binding with [(125)I]-orexin-A. Upon activation with orexin-A, OX2 receptors stimulated phospholipase A2, C and D, diacylglycerol lipase and calcium elevation, and both inhibited and stimulated adenylyl cyclase; i.e., the responses to OX2 activation by orexin-A were principally like those of OX1, in contrast to some previous suggestions. The responses occurred mostly in the same concentration range as those for OX1 activation and via the same signal cascades. However, some responses were weaker, suggesting a partially differential coupling to some cascades. In summary, OX2 receptor signalling is principally similar to OX1 receptor signalling suggesting also a physiologically similar coupling, though this needs to be verified in physiological contexts. Some (relatively weak) differences between the receptors may be investigated in further studies.
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22
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Karhu L, Turku A, Xhaard H. Modeling of the OX1R-orexin-A complex suggests two alternative binding modes. BMC STRUCTURAL BIOLOGY 2015; 15:9. [PMID: 25957175 PMCID: PMC4469407 DOI: 10.1186/s12900-015-0036-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/21/2015] [Indexed: 01/25/2023]
Abstract
Background Interactions between the orexin peptides and their cognate OX1 and OX2 receptors remain poorly characterized. Site-directed mutagenesis studies on orexin peptides and receptors have indicated amino acids important for ligand binding and receptor activation. However, a better understanding of specific pairwise interactions would benefit small molecule discovery. Results We constructed a set of three-dimensional models of the orexin 1 receptor based on the 3D-structures of the orexin 2 receptor (released while this manuscript was under review), neurotensin receptor 1 and chemokine receptor CXCR4, conducted an exhaustive docking of orexin-A16–33 peptide fragment with ZDOCK and RDOCK, and analyzed a total of 4301 complexes through multidimensional scaling and clustering. The best docking poses reveal two alternative binding modes, where the C-terminus of the peptide lies deep in the binding pocket, on average about 5–6 Å above Tyr6.48 and close to Gln3.32. The binding modes differ in the about 100° rotation of the peptide; the peptide His26 faces either the receptor’s fifth transmembrane helix or the seventh helix. Both binding modes are well in line with previous mutation studies and partake in hydrogen bonding similar to suvorexant. Conclusions We present two binding modes for orexin-A into orexin 1 receptor, which help rationalize previous results from site-directed mutagenesis studies. The binding modes should serve small molecule discovery, and offer insights into the mechanism of receptor activation. Electronic supplementary material The online version of this article (doi:10.1186/s12900-015-0036-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lasse Karhu
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
| | - Ainoleena Turku
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
| | - Henri Xhaard
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
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