1
|
Fan Z, Hao Y, Huo Y, Cao F, Li L, Xu J, Song Y, Yang K. Modulators for palmitoylation of proteins and small molecules. Eur J Med Chem 2024; 271:116408. [PMID: 38621327 DOI: 10.1016/j.ejmech.2024.116408] [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: 02/09/2024] [Revised: 04/03/2024] [Accepted: 04/10/2024] [Indexed: 04/17/2024]
Abstract
As an essential form of lipid modification for maintaining vital cellular functions, palmitoylation plays an important role in in the regulation of various physiological processes, serving as a promising therapeutic target for diseases like cancer and neurological disorders. Ongoing research has revealed that palmitoylation can be categorized into three distinct types: N-palmitoylation, O-palmitoylation and S-palmitoylation. Herein this paper provides an overview of the regulatory enzymes involved in palmitoylation, including palmitoyltransferases and depalmitoylases, and discusses the currently available broad-spectrum and selective inhibitors for these enzymes.
Collapse
Affiliation(s)
- Zeshuai Fan
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China
| | - Yuchen Hao
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China
| | - Yidan Huo
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China
| | - Fei Cao
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding, Hebei, 071002, China
| | - Longfei Li
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding, Hebei, 071002, China
| | - Jianmei Xu
- Department of hematopathology, Affiliated Hospital of Hebei University, Hebei University, Baoding, 071002, China
| | - Yali Song
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding, Hebei, 071002, China
| | - Kan Yang
- Key Laboratory of Pharmaceutical Quality Control of Hebei Province, College of Pharmaceutical Sciences, Hebei University, Baoding, 071002, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding, Hebei, 071002, China.
| |
Collapse
|
2
|
Pierce M, Ji J, Novak SX, Sieburg MA, Nangia S, Nangia S, Hougland JL. Combined Computational-Biochemical Approach Offers an Accelerated Path to Membrane Protein Solubilization. J Chem Inf Model 2023; 63:7159-7170. [PMID: 37939203 PMCID: PMC10685452 DOI: 10.1021/acs.jcim.3c00917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Membrane proteins are difficult to isolate and purify due to their dependence on the surrounding lipid membrane for structural stability. Detergents are often used to solubilize these proteins, with this approach requiring a careful balance between protein solubilization and denaturation. Determining which detergent is most appropriate for a given protein has largely been done empirically through screening, which requires large amounts of membrane protein and associated resources. Here, we describe an alternative to conventional detergent screening using a computational modeling approach to identify the most likely candidate detergents for solubilizing a protein of interest. We demonstrate our approach using ghrelin O-acyltransferase (GOAT), a member of the membrane-bound O-acyltransferase family of integral membrane enzymes that has not been solubilized or purified in active form. A computationally derived GOAT structural model provides the only structural information required for this approach. Using computational analysis of detergent ability to penetrate phospholipid bilayers and stabilize the GOAT structure, a panel of common detergents were rank-ordered for their proposed ability to solubilize GOAT. The simulations were performed at all-atom resolution for a combined simulation time of 24 μs. Independently, we biologically screened these detergents for their solubilization of fluorescently tagged GOAT constructs. We found computational prediction of protein structural stabilization was the better predictor of detergent solubilization ability, but neither approach was effective for predicting detergents that would support GOAT enzymatic function. The current rapid expansion of membrane protein computational models lacking experimental structural information and our computational detergent screening approach can greatly improve the efficiency of membrane protein detergent solubilization, supporting downstream functional and structural studies.
Collapse
Affiliation(s)
- Mariah
R. Pierce
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Jingjing Ji
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Sadie X. Novak
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Michelle A. Sieburg
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Shivangi Nangia
- Department
of Chemistry, University of Hartford, West Hartford, Connecticut 06117, United States
| | - Shikha Nangia
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
- BioInspired
Syracuse, Syracuse, New York 13244, United States
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
- BioInspired
Syracuse, Syracuse, New York 13244, United States
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
| |
Collapse
|
3
|
Li HZ, Wang YF, Zheng YS, Liu YL, Xu ZG, Guo ZY. The ghrelin receptor GHSR has two efficient agonists in the lobe-finned fish Latimeria chalumnae. Biochem Biophys Res Commun 2023; 679:110-115. [PMID: 37677979 DOI: 10.1016/j.bbrc.2023.09.002] [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: 08/14/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 09/09/2023]
Abstract
The peptide hormone ghrelin (an agonist) and LEAP2 (an antagonist) play important functions in energy metabolism via their receptor GHSR, an A-class G protein-coupled receptor. Ghrelin, LEAP2, and GHSR are widely present from fishes to mammals. However, our recent study suggested that fish GHSRs have different binding properties to ghrelin: a GHSR from the lobe-finned fish Latimeria chalumnae (coelacanth) is efficiently activated by ghrelin, but GHSRs from the ray-finned fish Danio rerio (zebrafish) and Larimichthys crocea (large yellow croaker) have lost binding to ghrelin. Do fish GHSRs use another peptide as their agonist? In the present study we tested to two fish motilins from D. rerio and L. chalumnae because motilin is distantly related to ghrelin. In ligand binding and activation assays, the fish GHSRs from D. rerio and L. crocea displayed no detectable or very low binding to all tested motilins; however, the fish GHSR from L. chalumnae bound to its motilin with high affinity and was efficiently activated by it. Therefore, it seemed that motilin is not a ligand for GHSR in the ray-finned fish D. rerio and L. crocea, but is an efficient agonist for GHSR in the lobe-finned fish L. chalumnae, one of the closest fish relatives of tetrapods. The results of present study suggested that GHSR might have two efficient agonists, ghrelin and motilin, in ancient fishes; however, this feature might be only preserved in some extant fishes with ancient evolutionary origins.
Collapse
Affiliation(s)
- Hao-Zheng Li
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ya-Fen Wang
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yong-Shan Zheng
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Ya-Li Liu
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zeng-Guang Xu
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhan-Yun Guo
- Research Center for Translational Medicine at East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China.
| |
Collapse
|
4
|
Campaña M, Davis TR, Novak SX, Cleverdon ER, Bates M, Krishnan N, Curtis ER, Childs MD, Pierce MR, Morales-Rodriguez Y, Sieburg MA, Hehnly H, Luyt LG, Hougland JL. Cellular Uptake of a Fluorescent Ligand Reveals Ghrelin O-Acyltransferase Interacts with Extracellular Peptides and Exhibits Unexpected Localization for a Secretory Pathway Enzyme. ACS Chem Biol 2023; 18:1880-1890. [PMID: 37494676 PMCID: PMC10442857 DOI: 10.1021/acschembio.3c00334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023]
Abstract
Ghrelin O-acyltransferase (GOAT) plays a central role in the maturation and activation of the peptide hormone ghrelin, which performs a wide range of endocrinological signaling roles. Using a tight-binding fluorescent ghrelin-derived peptide designed for high selectivity for GOAT over the ghrelin receptor GHSR, we demonstrate that GOAT interacts with extracellular ghrelin and facilitates ligand cell internalization in both transfected cells and prostate cancer cells endogenously expressing GOAT. Coupled with enzyme mutagenesis, ligand uptake studies support the interaction of the putative histidine general base within GOAT with the ghrelin peptide acylation site. Our work provides a new understanding of GOAT's catalytic mechanism, establishes that GOAT can interact with ghrelin and other peptides located outside the cell, and raises the possibility that other peptide hormones may exhibit similar complexity in their intercellular and organismal-level signaling pathways.
Collapse
Affiliation(s)
- Maria
B. Campaña
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Tasha R. Davis
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Sadie X. Novak
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | | | - Michael Bates
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
| | - Nikhila Krishnan
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
| | - Erin R. Curtis
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
| | - Marina D. Childs
- Department
of Chemistry, University of Western Ontario, London, Ontario N6A 2K7, Canada
| | - Mariah R. Pierce
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | | | - Michelle A. Sieburg
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Heidi Hehnly
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
- BioInspired
Syracuse, Syracuse University, Syracuse, New York 13244, United States
| | - Leonard G. Luyt
- Department
of Chemistry, University of Western Ontario, London, Ontario N6A 2K7, Canada
- Department
of Oncology and Department of Medical Imaging, London Regional Cancer
Program, Lawson Health Research Institute, 800 Commissioners Road East, London, Ontario N6A 5W9, Canada
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
- Department
of Biology, Syracuse University, Syracuse, New York 13244, United States
- BioInspired
Syracuse, Syracuse University, Syracuse, New York 13244, United States
| |
Collapse
|
5
|
Thomas AS, Sassi M, Angelini R, Morgan AH, Davies JS. Acylation, a Conductor of Ghrelin Function in Brain Health and Disease. Front Physiol 2022; 13:831641. [PMID: 35845996 PMCID: PMC9280358 DOI: 10.3389/fphys.2022.831641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
Acyl-ghrelin (AG) is an orexigenic hormone that has a unique octanoyl modification on its third serine residue. It is often referred to as the “hunger hormone” due to its involvement in stimulating food intake and regulating energy homeostasis. The discovery of the enzyme ghrelin-O-acyltransferase (GOAT), which catalyses ghrelin acylation, provided further insights into the relevance of this lipidation process for the activation of the growth hormone secretagogue receptor (GHS-R) by acyl-ghrelin. Although acyl-ghrelin is predominantly linked with octanoic acid, a range of saturated fatty acids can also bind to ghrelin possibly leading to specific functions. Sources of ghrelin acylation include beta-oxidation of longer chain fatty acids, with contributions from fatty acid synthesis, the diet, and the microbiome. In addition, both acyl-ghrelin and unacyl-ghrelin (UAG) have feedback effects on lipid metabolism which in turn modulate their levels. Recently we showed that whilst acyl-ghrelin promotes adult hippocampal neurogenesis and enhances memory function, UAG inhibits these processes. As a result, we postulated that the circulating acyl-ghrelin:unacyl-ghrelin (AG:UAG) ratio might be an important regulator of neurogenesis and cognition. In this review, we discuss emerging evidence behind the relevance of ghrelin acylation in the context of brain physiology and pathology, as well as the current challenges of identifying the provenance of the acyl moiety.
Collapse
|
6
|
Deschaine SL, Farokhnia M, Gregory-Flores A, Zallar LJ, You ZB, Sun H, Harvey DM, Marchette RCN, Tunstall BJ, Mani BK, Moose JE, Lee MR, Gardner E, Akhlaghi F, Roberto M, Hougland JL, Zigman JM, Koob GF, Vendruscolo LF, Leggio L. A closer look at alcohol-induced changes in the ghrelin system: novel insights from preclinical and clinical data. Addict Biol 2022; 27:e13033. [PMID: 33908131 PMCID: PMC8548413 DOI: 10.1111/adb.13033] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/16/2021] [Accepted: 03/06/2021] [Indexed: 02/06/2023]
Abstract
Ghrelin is a gastric-derived peptide hormone with demonstrated impact on alcohol intake and craving, but the reverse side of this bidirectional link, that is, the effects of alcohol on the ghrelin system, remains to be fully established. To further characterize this relationship, we examined (1) ghrelin levels via secondary analysis of human laboratory alcohol administration experiments with heavy-drinking participants; (2) expression of ghrelin, ghrelin receptor, and ghrelin-O-acyltransferase (GOAT) genes (GHRL, GHSR, and MBOAT4, respectively) in post-mortem brain tissue from individuals with alcohol use disorder (AUD) versus controls; (3) ghrelin levels in Ghsr knockout and wild-type rats following intraperitoneal (i.p.) alcohol administration; (4) effect of alcohol on ghrelin secretion from gastric mucosa cells ex vivo and GOAT enzymatic activity in vitro; and (5) ghrelin levels in rats following i.p. alcohol administration versus a calorically equivalent non-alcoholic sucrose solution. Acyl- and total-ghrelin levels decreased following acute alcohol administration in humans, but AUD was not associated with changes in central expression of ghrelin system genes in post-mortem tissue. In rats, alcohol decreased acyl-ghrelin, but not des-acyl-ghrelin, in both Ghsr knockout and wild-type rats. No dose-dependent effects of alcohol were observed on acyl-ghrelin secretion from gastric mucosa cells or on GOAT acylation activity. Lastly, alcohol and sucrose produced distinct effects on ghrelin in rats despite equivalent caloric value. Our findings suggest that alcohol acutely decreases peripheral ghrelin concentrations in vivo, but not in proportion to alcohol's caloric value or through direct interaction with ghrelin-secreting gastric mucosal cells, the ghrelin receptor, or the GOAT enzyme.
Collapse
Affiliation(s)
- Sara L. Deschaine
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA
| | - Mehdi Farokhnia
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Adriana Gregory-Flores
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Lia J. Zallar
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Zhi-Bing You
- Neuropsychopharmacology Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Hui Sun
- Clinical Core Laboratory, Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Deon M. Harvey
- Office of the Scientific Director, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Renata C. N. Marchette
- Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Brendan J. Tunstall
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Bharath K. Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jacob E. Moose
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, USA,Department of Chemistry, Syracuse University, Syracuse, New York, USA
| | - Mary R. Lee
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA
| | - Eliot Gardner
- Neuropsychopharmacology Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Fatemeh Akhlaghi
- Clinical Pharmacokinetics Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Marisa Roberto
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, USA
| | - James L. Hougland
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, USA,Department of Chemistry, Syracuse University, Syracuse, New York, USA,BioInspired Syracuse, Syracuse University, Syracuse, New York, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA,Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA,Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
| | - George F. Koob
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Leandro F. Vendruscolo
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA,Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island, USA,Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA,Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
| |
Collapse
|
7
|
Davis TR, Pierce MR, Novak SX, Hougland JL. Ghrelin octanoylation by ghrelin O-acyltransferase: protein acylation impacting metabolic and neuroendocrine signalling. Open Biol 2021; 11:210080. [PMID: 34315274 PMCID: PMC8316800 DOI: 10.1098/rsob.210080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The acylated peptide hormone ghrelin impacts a wide range of physiological processes but is most well known for controlling hunger and metabolic regulation. Ghrelin requires a unique posttranslational modification, serine octanoylation, to bind and activate signalling through its cognate GHS-R1a receptor. Ghrelin acylation is catalysed by ghrelin O-acyltransferase (GOAT), a member of the membrane-bound O-acyltransferase (MBOAT) enzyme family. The ghrelin/GOAT/GHS-R1a system is defined by multiple unique aspects within both protein biochemistry and endocrinology. Ghrelin serves as the only substrate for GOAT within the human proteome and, among the multiple hormones involved in energy homeostasis and metabolism such as insulin and leptin, acts as the only known hormone in circulation that directly stimulates appetite and hunger signalling. Advances in GOAT enzymology, structural modelling and inhibitor development have revolutionized our understanding of this enzyme and offered new tools for investigating ghrelin signalling at the molecular and organismal levels. In this review, we briefly summarize the current state of knowledge regarding ghrelin signalling and ghrelin/GOAT enzymology, discuss the GOAT structural model in the context of recently reported MBOAT enzyme superfamily member structures, and highlight the growing complement of GOAT inhibitors that offer options for both ghrelin signalling studies and therapeutic applications.
Collapse
Affiliation(s)
- Tasha R Davis
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - Mariah R Pierce
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - Sadie X Novak
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA.,BioInspired Syracuse, Syracuse University, Syracuse, NY 13244 USA
| |
Collapse
|
8
|
Iyer MR, Wood CM, Kunos G. Recent progress in the discovery of ghrelin O-acyltransferase (GOAT) inhibitors. RSC Med Chem 2020; 11:1136-1144. [PMID: 33479618 PMCID: PMC7651998 DOI: 10.1039/d0md00210k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/03/2020] [Indexed: 12/29/2022] Open
Abstract
Ghrelin is a stomach-derived peptide hormone which stimulates appetite. For ghrelin to exert its orexigenic effect, octanoylation on the serine-3 residue of this gut-brain peptide is essential. The octanoylation of ghrelin is mediated by a unique acyltransferase enzyme known as ghrelin O-acyltransferase (GOAT). Thus modulating this enzyme offers viable approaches to alter feeding behaviors. Over the past decade, several small-molecule based approaches have appeared dealing with the discovery of compounds able to modulate this enzyme for the treatment of obesity and type 2 diabetes. Drug discovery efforts from academic groups and several pharmaceutical companies have fielded compounds having efficacy in altering acylated ghrelin levels in animal models but to date, compounds modulating the activity of the GOAT enzyme do not yet represent clinical options. This mini-review covers the drug discovery approaches of the last decade since the discovery of the GOAT enzyme.
Collapse
Affiliation(s)
- Malliga R Iyer
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
| | - Casey M Wood
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
| | - George Kunos
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
| |
Collapse
|
9
|
Moose JE, Leets KA, Mate NA, Chisholm JD, Hougland JL. An overview of ghrelin O-acyltransferase inhibitors: a literature and patent review for 2010-2019. Expert Opin Ther Pat 2020; 30:581-593. [PMID: 32564644 DOI: 10.1080/13543776.2020.1776263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The peptide hormone ghrelin regulates physiological processes associated with energy homeostasis such as appetite, insulin signaling, glucose metabolism, and adiposity. Ghrelin has also been implicated in a growing number of neurological pathways involved in stress response and addiction behavior. For ghrelin to bind the growth hormone secretagogue receptor 1a (GHS-R1a) and activate signaling, the hormone must first be octanoylated on a specific serine side chain. This key transformation is performed by the enzyme ghrelin O-acyltransferase (GOAT), and therefore GOAT inhibitors may be useful in treating disorders related to ghrelin signaling such as diabetes, obesity, and related metabolic syndromes. AREAS COVERED This report covers ghrelin and GOAT as potential therapeutic targets and summarizes work on GOAT inhibitors through the end of 2019, highlighting recent successes with both peptidomimetics and small molecule GOAT inhibitors as potent modulators of GOAT-catalyzed ghrelin octanoylation. EXPERT OPINION A growing body of biochemical and structural knowledge regarding the ghrelin/GOAT system now enables multiple avenues for identifying and optimizing GOAT inhibitors. We are at the beginning of a new era with increased opportunities for leveraging ghrelin and GOAT in the understanding and treatment of multiple health conditions including diabetes, obesity, and addiction.
Collapse
Affiliation(s)
- Jacob E Moose
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - Katelyn A Leets
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - Nilamber A Mate
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - John D Chisholm
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - James L Hougland
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| |
Collapse
|
10
|
Abizaid A, Hougland JL. Ghrelin Signaling: GOAT and GHS-R1a Take a LEAP in Complexity. Trends Endocrinol Metab 2020; 31:107-117. [PMID: 31636018 PMCID: PMC7299083 DOI: 10.1016/j.tem.2019.09.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/30/2022]
Abstract
Ghrelin and the growth hormone secretagogue receptor 1a (GHS-R1a) are important targets for disorders related to energy balance and metabolic regulation. Pharmacological control of ghrelin signaling is a promising avenue to address health issues involving appetite, weight gain, obesity, and related metabolic disorders, and may be an option for patients suffering from wasting conditions like cachexia. In this review, we summarize recent developments in the biochemistry of ghrelin and GHS-R1a signaling. These include unravelling the enzymatic transformations that generate active ghrelin and the discovery of multiple proteins that interact with ghrelin and GHS-R1a to regulate signaling. Furthermore, we propose that harnessing these processes will lead to highly selective treatments to address obesity, diabetes, and other metabolism-linked disorders.
Collapse
Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
| |
Collapse
|
11
|
Campaña MB, Irudayanathan FJ, Davis TR, McGovern-Gooch KR, Loftus R, Ashkar M, Escoffery N, Navarro M, Sieburg MA, Nangia S, Hougland JL. The ghrelin O-acyltransferase structure reveals a catalytic channel for transmembrane hormone acylation. J Biol Chem 2019; 294:14166-14174. [PMID: 31413115 DOI: 10.1074/jbc.ac119.009749] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/12/2019] [Indexed: 01/17/2023] Open
Abstract
Integral membrane proteins represent a large and diverse portion of the proteome and are often recalcitrant to purification, impeding studies essential for understanding protein structure and function. By combining co-evolutionary constraints and computational modeling with biochemical validation through site-directed mutagenesis and enzyme activity assays, we demonstrate here a synergistic approach to structurally model purification-resistant topologically complex integral membrane proteins. We report the first structural model of a eukaryotic membrane-bound O-acyltransferase (MBOAT), ghrelin O-acyltransferase (GOAT), which modifies the metabolism-regulating hormone ghrelin. Our structure, generated in the absence of any experimental structural data, revealed an unanticipated strategy for transmembrane protein acylation with catalysis occurring in an internal channel connecting the endoplasmic reticulum lumen and cytoplasm. This finding validated the power of our approach to generate predictive structural models for other experimentally challenging integral membrane proteins. Our results illuminate novel aspects of membrane protein function and represent key steps for advancing structure-guided inhibitor design to target therapeutically important but experimentally intractable membrane proteins.
Collapse
Affiliation(s)
- Maria B Campaña
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | | | - Tasha R Davis
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | | | - Rosemary Loftus
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | - Mohammad Ashkar
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | - Najae Escoffery
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | - Melissa Navarro
- Department of Chemistry, Syracuse University, Syracuse, New York 13244
| | | | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244 .,Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York 13244
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, New York 13244 .,Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York 13244
| |
Collapse
|
12
|
Ghrelin octanoylation by ghrelin O-acyltransferase: Unique protein biochemistry underlying metabolic signaling. Biochem Soc Trans 2019; 47:169-178. [PMID: 30626708 DOI: 10.1042/bst20180436] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023]
Abstract
Ghrelin is a small peptide hormone that requires a unique post-translational modification, serine octanoylation, to bind and activate the GHS-R1a receptor. Ghrelin signaling is implicated in a variety of neurological and physiological processes, but is most well known for its roles in controlling hunger and metabolic regulation. Ghrelin octanoylation is catalyzed by ghrelin O-acyltransferase (GOAT), a member of the membrane-bound O-acyltransferase (MBOAT) enzyme family. From the status of ghrelin as the only substrate for GOAT in the human genome to the source and requirement for the octanoyl acyl donor, the ghrelin-GOAT system is defined by multiple unique aspects within both protein biochemistry and endocrinology. In this review, we examine recent advances in our understanding of the interactions and mechanisms leading to ghrelin modification by GOAT, discuss the potential sources for the octanoyl acyl donor required for ghrelin's activation, and summarize the current landscape of molecules targeting ghrelin octanoylation through GOAT inhibition.
Collapse
|
13
|
Sieburg MA, Cleverdon ER, Hougland JL. Biochemical Assays for Ghrelin Acylation and Inhibition of Ghrelin O-Acyltransferase. Methods Mol Biol 2019; 2009:227-241. [PMID: 31152408 DOI: 10.1007/978-1-4939-9532-5_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ghrelin O-acyltransferase (GOAT) is an enzyme responsible for octanoylating and activating ghrelin, a peptide hormone that plays a key role in energy regulation and hunger signaling. Due to its nature as an integral membrane protein, GOAT has yet to be purified in active form which has complicated biochemical and structural studies of GOAT-catalyzed ghrelin acylation. In this chapter, we describe protocols for efficient expression and enrichment of GOAT in insect cell-derived microsomal fraction, HPLC-based assays for GOAT acylation activity employing fluorescently labeled peptides, and assessment of inhibitor potency against GOAT.
Collapse
Affiliation(s)
| | | | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
| |
Collapse
|
14
|
Lemarié F, Beauchamp E, Drouin G, Legrand P, Rioux V. Dietary caprylic acid and ghrelin O-acyltransferase activity to modulate octanoylated ghrelin functions: What is new in this nutritional field? Prostaglandins Leukot Essent Fatty Acids 2018; 135:121-127. [PMID: 30103923 DOI: 10.1016/j.plefa.2018.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 12/15/2022]
Abstract
Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils such as coconut oil are natural sources of dietary caprylic acid. MCFAs display distinct chemico-physical and metabolic properties from those of long-chain saturated fatty acids (LCFAs ≥ 12 carbons) and potential beneficial physiological effects of dietary C8:0 have been studied for many years. More recently, caprylic acid was shown to octanoylate ghrelin, the only known peptide hormone with an orexigenic effect. Through its covalent binding to the ghrelin peptide, caprylic acid exhibits an emerging and specific role in modulating physiological functions themselves regulated by octanoylated ghrelin. Dietary caprylic acid is therefore now suspected to provide the ghrelin O-acyltransferase (GOAT) enzyme with octanoyl-CoA co-substrates necessary for the acyl modification of ghrelin. Recent studies suggest that decreasing the circulating octanoylated ghrelin level through the inhibition of GOAT activity, or simply by modulating the availability of its C8:0 substrate, might constitute a therapeutic strategy against obesity. Both dietary caprylic acid availability and GOAT activity may indeed be important to modulate octanoylated ghrelin concentration and functions. This review highlights recent findings in the field of nutrition.
Collapse
Affiliation(s)
- Fanny Lemarié
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France; Centre for Molecular Medicine and Therapeutics (CMMT), The University of British Columbia, BC Children's Hospital Research Institute, Vancouver, Canada
| | - Erwan Beauchamp
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Gaëtan Drouin
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Philippe Legrand
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Vincent Rioux
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France.
| |
Collapse
|
15
|
Abstract
Click chemistry has emerged as a powerful tool in our arsenal for unlocking new biology. This includes its utility in both chemical biology and drug discovery. An emerging application of click chemistry is in the development of biochemical assays for high-throughput screening to identify new chemical probes and drug leads. This Feature Article will discuss the advancements in click chemistry that were necessary for the development of a new class of biochemical assay, catalytic enzyme-linked click chemistry assay or cat-ELCCA. Inspired by enzyme immunoassays, cat-ELCCA was designed as a click chemistry-based amplification assay where bioorthogonally-tagged analytes and enzymes are used in place of the enzyme-linked secondary antibodies used in immunoassays. The result is a robust assay format with demonstrated applicability in several important areas of biology and drug discovery, including post-translational modifications, pre-microRNA maturation, and protein-protein and RNA-protein interactions. Through the use of cat-ELCCA and other related click chemistry-based assays, new chemical probes for interrogating promising drug targets have been discovered. These examples will be discussed, in addition to a future outlook on the impact of this approach in probe and drug discovery.
Collapse
Affiliation(s)
- Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 1600 Huron Parkway, NCRC B520, Ann Arbor, Michigan 48109, USA.
| |
Collapse
|
16
|
Cleverdon ER, Davis TR, Hougland JL. Functional group and stereochemical requirements for substrate binding by ghrelin O-acyltransferase revealed by unnatural amino acid incorporation. Bioorg Chem 2018; 79:98-106. [PMID: 29738973 DOI: 10.1016/j.bioorg.2018.04.009] [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] [Received: 02/08/2018] [Revised: 04/02/2018] [Accepted: 04/13/2018] [Indexed: 12/22/2022]
Abstract
Ghrelin is a small peptide hormone that undergoes a unique posttranslational modification, serine octanoylation, to play its physiological roles in processes including hunger signaling and glucose metabolism. Ghrelin O-acyltransferase (GOAT) catalyzes this posttranslational modification, which is essential for ghrelin to bind and activate its cognate GHS-R1a receptor. Inhibition of GOAT offers a potential avenue for modulating ghrelin signaling for therapeutic effect. Defining the molecular characteristics of ghrelin that lead to binding and recognition by GOAT will facilitate the development and optimization of GOAT inhibitors. We show that small peptide mimics of ghrelin substituted with 2,3-diaminopropanoic acid in place of the serine at the site of octanoylation act as submicromolar inhibitors of GOAT. Using these chemically modified analogs of desacyl ghrelin, we define key functional groups within the N-terminal sequence of ghrelin essential for binding to GOAT and determine GOAT's tolerance to backbone methylations and altered amino acid stereochemistry within ghrelin. Our study provides a structure-activity analysis of ghrelin binding to GOAT that expands upon activity-based investigations of ghrelin recognition and establishes a new class of potent substrate-mimetic GOAT inhibitors for further investigation and therapeutic interventions targeting ghrelin signaling.
Collapse
Affiliation(s)
| | - Tasha R Davis
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA.
| |
Collapse
|
17
|
Cleverdon ER, McGovern-Gooch KR, Hougland JL. The octanoylated energy regulating hormone ghrelin: An expanded view of ghrelin's biological interactions and avenues for controlling ghrelin signaling. Mol Membr Biol 2017; 33:111-124. [PMID: 29143554 DOI: 10.1080/09687688.2017.1388930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ghrelin is a small peptide hormone that requires a unique post-translational modification, serine octanoylation, to bind and activate the GHS-R1a receptor. Initially demonstrated to stimulate hunger and appetite, ghrelin-dependent signaling is implicated in a variety of neurological and physiological processes influencing diseases such as diabetes, obesity, and Prader-Willi syndrome. In addition to its cognate receptor, recent studies have revealed ghrelin interacts with a range of binding partners within the bloodstream. Defining the scope of ghrelin's interactions within the body, understanding how these interactions work in concert to modulate ghrelin signaling, and developing molecular tools for controlling ghrelin signaling are essential for exploiting ghrelin for therapeutic effect. In this review, we discuss recent findings regarding the biological effects of ghrelin signaling, outline binding partners that control ghrelin trafficking and stability in circulation, and summarize the current landscape of inhibitors targeting ghrelin octanoylation.
Collapse
Affiliation(s)
| | | | - James L Hougland
- a Department of Chemistry , Syracuse University , Syracuse , NY , USA
| |
Collapse
|
18
|
Yoneyama-Hirozane M, Deguchi K, Hirakawa T, Ishii T, Odani T, Matsui J, Nakano Y, Imahashi K, Takakura N, Chisaki I, Takekawa S, Sakamoto J. Identification and Characterization of a New Series of Ghrelin O-Acyl Transferase Inhibitors. SLAS DISCOVERY 2017; 23:154-163. [PMID: 28846466 DOI: 10.1177/2472555217727097] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ghrelin O-acyl transferase (GOAT; MBOAT4) catalyzes O-acylation at serine-3 of des-acyl ghrelin. Acyl ghrelin is secreted by stomach X/A-like cells and plays a role in appetite and metabolism. Therefore, GOAT has been expected to be a novel antiobesity target because it is responsible for acyl ghrelin production. Here, we report homogeneous time-resolved fluorescence (HTRF) and enzyme-linked immunosorbent assay (ELISA) methods utilizing human GOAT-expressing microsomes as a novel high-throughput assay system for the discovery of hit compounds and optimization of lead compounds. Hit compounds exemplified by compound A (2-[(2,4-dichlorobenzyl)sulfanyl]-1,3-benzoxazole-5-carboxylic acid) were identified by high-throughput screening using the HTRF assay and confirmed to have GOAT inhibitory activity using the ELISA. Based on the hit compound information, the novel lead compound (compound B, (4-chloro-6-{[2-methyl-6-(trifluoromethyl)pyridin-3-yl]methoxy}-1-benzothiophen-3-yl)acetic acid) was synthesized and exhibited potent GOAT inhibition with oral bioavailability. Both the hit compound and lead compound showed octanoyl-CoA competitive inhibitory activity. Moreover, these two compounds decreased acyl ghrelin production in the stomach of mice after their oral administration. These novel findings demonstrate that GOAT is a druggable target, and its inhibitors are promising antiobesity drugs.
Collapse
Affiliation(s)
| | - Kohei Deguchi
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Takeshi Hirakawa
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Tsuyoshi Ishii
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Tomoyuki Odani
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Junji Matsui
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Yoshihide Nakano
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Kenichi Imahashi
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | | | - Ikumi Chisaki
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Shiro Takekawa
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Junichi Sakamoto
- 1 Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| |
Collapse
|
19
|
McGovern-Gooch KR, Mahajani NS, Garagozzo A, Schramm AJ, Hannah LG, Sieburg MA, Chisholm JD, Hougland JL. Synthetic Triterpenoid Inhibition of Human Ghrelin O-Acyltransferase: The Involvement of a Functionally Required Cysteine Provides Mechanistic Insight into Ghrelin Acylation. Biochemistry 2017; 56:919-931. [PMID: 28134508 DOI: 10.1021/acs.biochem.6b01008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The peptide hormone ghrelin plays a key role in regulating hunger and energy balance within the body. Ghrelin signaling presents a promising and unexploited target for development of small molecule therapeutics for treatment of obesity, diabetes, and other health conditions. Inhibition of ghrelin O-acyltransferase (GOAT), which catalyzes an essential octanoylation step in ghrelin maturation, offers a potential avenue for controlling ghrelin signaling. Through screening a small molecule library, we have identified a class of synthetic triterpenoids that efficiently inhibit ghrelin acylation by the human isoform of GOAT (hGOAT). These compounds function as covalent reversible inhibitors of hGOAT, providing the first evidence of the involvement of a nucleophilic cysteine residue in substrate acylation by a MBOAT family acyltransferase. Surprisingly, the mouse form of GOAT does not exhibit susceptibility to cysteine-modifying electrophiles, revealing an important distinction in the activity and behavior between these closely related GOAT isoforms. This study establishes these compounds as potent small molecule inhibitors of ghrelin acylation and provides a foundation for the development of novel hGOAT inhibitors as therapeutics targeting diabetes and obesity.
Collapse
Affiliation(s)
| | - Nivedita S Mahajani
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Ariana Garagozzo
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Anthony J Schramm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Lauren G Hannah
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Michelle A Sieburg
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - John D Chisholm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - James L Hougland
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| |
Collapse
|
20
|
McGovern-Gooch KR, Rodrigues T, Darling JE, Sieburg MA, Abizaid A, Hougland JL. Ghrelin Octanoylation Is Completely Stabilized in Biological Samples by Alkyl Fluorophosphonates. Endocrinology 2016; 157:4330-4338. [PMID: 27623288 DOI: 10.1210/en.2016-1657] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin is a peptide hormone involved in multiple physiological processes related to energy homeostasis. This hormone features a unique posttranslational serine octanoylation modification catalyzed by the enzyme ghrelin O-acyltransferase, with serine octanoylation essential for ghrelin to bind and activate its cognate receptor. Ghrelin deacylation rapidly occurs in circulation, with both ghrelin and desacyl ghrelin playing important roles in biological signaling. Understanding the regulation and physiological impact of ghrelin signaling requires the ability to rapidly protect ghrelin from deacylation in biological samples such as blood serum or cell lysates to preserve the relative concentrations of ghrelin and desacyl ghrelin. In in vitro ghrelin O-acyltransferase activity assays using insect microsomal protein fractions and mammalian cell lysate and blood serum, we demonstrate that alkyl fluorophosphonate treatment provides rapid, complete, and long-lasting protection of ghrelin acylation against serine ester hydrolysis without interference in enzyme assay or ELISA analysis. Our results support alkyl fluorophosphonate treatment as a general tool for stabilizing ghrelin and improving measurement of ghrelin and desacyl ghrelin concentrations in biochemical and clinical investigations and suggest current estimates for active ghrelin concentration and the ghrelin to desacyl ghrelin ratio in circulation may underestimate in vivo conditions.
Collapse
Affiliation(s)
- Kayleigh R McGovern-Gooch
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Trevor Rodrigues
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Joseph E Darling
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Michelle A Sieburg
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Alfonso Abizaid
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - James L Hougland
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| |
Collapse
|
21
|
Taylor MS, Dempsey DR, Hwang Y, Chen Z, Chu N, Boeke JD, Cole PA. Mechanistic analysis of ghrelin-O-acyltransferase using substrate analogs. Bioorg Chem 2015; 62:64-73. [PMID: 26246082 DOI: 10.1016/j.bioorg.2015.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 11/15/2022]
Abstract
Ghrelin-O-Acyltransferase (GOAT) is an 11-transmembrane integral membrane protein that octanoylates the metabolism-regulating peptide hormone ghrelin at Ser3 and may represent an attractive target for the treatment of type II diabetes and the metabolic syndrome. Protein octanoylation is unique to ghrelin in humans, and little is known about the mechanism of GOAT or of related protein-O-acyltransferases HHAT or PORC. In this study, we explored an in vitro microsomal ghrelin octanoylation assay to analyze its enzymologic features. Measurement of Km for 10-mer, 27-mer, and synthetic Tat-peptide-containing ghrelin substrates provided evidence for a role of charge interactions in substrate binding. Ghrelin substrates with amino-alanine in place of Ser3 demonstrated that GOAT can catalyze the formation of an octanoyl-amide bond at a similar rate compared with the natural reaction. A pH-rate comparison of these substrates revealed minimal differences in acyltransferase activity across pH 6.0-9.0, providing evidence that these reactions may be relatively insensitive to the basicity of the substrate nucleophile. The conserved His338 residue was required both for Ser3 and amino-Ala3 ghrelin substrates, suggesting that His338 may have a key catalytic role beyond that of a general base.
Collapse
Affiliation(s)
- Martin S Taylor
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Molecular Biology & Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Daniel R Dempsey
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yousang Hwang
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zan Chen
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nam Chu
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jef D Boeke
- Department of Molecular Biology & Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Philip A Cole
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
22
|
A new class of ghrelin O-acyltransferase inhibitors incorporating triazole-linked lipid mimetic groups. Bioorg Med Chem Lett 2015; 25:2800-3. [PMID: 26009163 DOI: 10.1016/j.bmcl.2015.05.009] [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: 02/28/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 02/06/2023]
Abstract
Inhibitors of ghrelin O-acyltransferase (GOAT) have untapped potential as therapeutics targeting obesity and diabetes. We report the first examples of GOAT inhibitors incorporating a triazole linkage as a biostable isosteric replacement for the ester bond in ghrelin and amide bonds in previously reported GOAT inhibitors. These triazole-containing inhibitors exhibit sub-micromolar inhibition of the human isoform of GOAT (hGOAT), and provide a foundation for rapid future chemical diversification and optimization of hGOAT inhibitors.
Collapse
|
23
|
Martínez-García G, Serafín V, Agüí L, Yáñez-Sedeño P, Pingarrón JM. Electrochemical Immunosensor for the Determination of Total Ghrelin Hormone in Saliva. ELECTROANAL 2015. [DOI: 10.1002/elan.201400662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
24
|
Darling JE, Zhao F, Loftus RJ, Patton LM, Gibbs RA, Hougland JL. Structure–Activity Analysis of Human Ghrelin O-Acyltransferase Reveals Chemical Determinants of Ghrelin Selectivity and Acyl Group Recognition. Biochemistry 2015; 54:1100-10. [DOI: 10.1021/bi5010359] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph E. Darling
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Feifei Zhao
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rosemary J. Loftus
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Leslie M. Patton
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Richard A. Gibbs
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| |
Collapse
|
25
|
Wellman MK, Patterson ZR, MacKay H, Darling JE, Mani BK, Zigman JM, Hougland JL, Abizaid A. Novel Regulator of Acylated Ghrelin, CF801, Reduces Weight Gain, Rebound Feeding after a Fast, and Adiposity in Mice. Front Endocrinol (Lausanne) 2015; 6:144. [PMID: 26441834 PMCID: PMC4585333 DOI: 10.3389/fendo.2015.00144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/01/2015] [Indexed: 01/04/2023] Open
Abstract
Ghrelin is a 28 amino acid hormonal peptide that is intimately related to the regulation of food intake and body weight. Once secreted, ghrelin binds to the growth hormone secretagogue receptor-1a, the only known receptor for ghrelin and is capable of activating a number of signaling cascades, ultimately resulting in an increase in food intake and adiposity. Because ghrelin has been linked to overeating and the development of obesity, a number of pharmacological interventions have been generated in order to interfere with either the activation of ghrelin or interrupting ghrelin signaling as a means to reducing appetite and decrease weight gain. Here, we present a novel peptide, CF801, capable of reducing circulating acylated ghrelin levels and subsequent body weight gain and adiposity. To this end, we show that IP administration of CF801 is sufficient to reduce circulating plasma acylated ghrelin levels. Acutely, intraperitoneal injections of CF801 resulted in decreased rebound feeding after an overnight fast. When delivered chronically, they decreased weight gain and adiposity without affecting caloric intake. CF801, however, did cause a change in diet preference, decreasing preference for a high-fat diet and increasing preference for regular chow diet. Given the complexity of ghrelin receptor function, we propose that CF801, along with other compounds that regulate ghrelin secretion, may prove to be a beneficial tool in the study of the ghrelin system, and potential targets for ghrelin-based obesity treatments without altering the function of ghrelin receptors.
Collapse
Affiliation(s)
| | | | - Harry MacKay
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | - Bharath K. Mani
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
- *Correspondence: Alfonso Abizaid, Department of Neuroscience, Carleton University, 1125 Colonel By Drive, 329 Life Science Research Building, Ottawa, ON K1S 5B6, Canada,
| |
Collapse
|
26
|
Delporte C. Structure and physiological actions of ghrelin. SCIENTIFICA 2013; 2013:518909. [PMID: 24381790 PMCID: PMC3863518 DOI: 10.1155/2013/518909] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/10/2013] [Indexed: 05/30/2023]
Abstract
Ghrelin is a gastric peptide hormone, discovered as being the endogenous ligand of growth hormone secretagogue receptor. Ghrelin is a 28 amino acid peptide presenting a unique n-octanoylation modification on its serine in position 3, catalyzed by ghrelin O-acyl transferase. Ghrelin is mainly produced by a subset of stomach cells and also by the hypothalamus, the pituitary, and other tissues. Transcriptional, translational, and posttranslational processes generate ghrelin and ghrelin-related peptides. Homo- and heterodimers of growth hormone secretagogue receptor, and as yet unidentified receptors, are assumed to mediate the biological effects of acyl ghrelin and desacyl ghrelin, respectively. Ghrelin exerts wide physiological actions throughout the body, including growth hormone secretion, appetite and food intake, gastric secretion and gastrointestinal motility, glucose homeostasis, cardiovascular functions, anti-inflammatory functions, reproductive functions, and bone formation. This review focuses on presenting the current understanding of ghrelin and growth hormone secretagogue receptor biology, as well as the main physiological effects of ghrelin.
Collapse
Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, 808 Route de Lennik, Bat G/E-CP611, 1070 Brussels, Belgium
| |
Collapse
|