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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.
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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.
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2
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Banahene N, Peters-Clarke TM, Biegas KJ, Shishkova E, Hart EM, McKitterick AC, Kambitsis NH, Johnson UG, Bernhardt TG, Coon JJ, Swarts BM. Chemical Proteomics Strategies for Analyzing Protein Lipidation Reveal the Bacterial O-Mycoloylome. J Am Chem Soc 2024; 146:12138-12154. [PMID: 38635392 PMCID: PMC11066868 DOI: 10.1021/jacs.4c02278] [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: 02/14/2024] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/20/2024]
Abstract
Protein lipidation dynamically controls protein localization and function within cellular membranes. A unique form of protein O-fatty acylation in Corynebacterium, termed protein O-mycoloylation, involves the attachment of mycolic acids─unusually large and hydrophobic fatty acids─to serine residues of proteins in these organisms' outer mycomembrane. However, as with other forms of protein lipidation, the scope and functional consequences of protein O-mycoloylation are challenging to investigate due to the inherent difficulties of enriching and analyzing lipidated peptides. To facilitate the analysis of protein lipidation and enable the comprehensive profiling and site mapping of protein O-mycoloylation, we developed a chemical proteomics strategy integrating metabolic labeling, click chemistry, cleavable linkers, and a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method employing LC separation and complementary fragmentation methods tailored to the analysis of lipophilic, MS-labile O-acylated peptides. Using these tools in the model organism Corynebacterium glutamicum, we identified approximately 30 candidate O-mycoloylated proteins, including porins, mycoloyltransferases, secreted hydrolases, and other proteins with cell envelope-related functions─consistent with a role for O-mycoloylation in targeting proteins to the mycomembrane. Site mapping revealed that many of the proteins contained multiple spatially proximal modification sites, which occurred predominantly at serine residues surrounded by conformationally flexible peptide motifs. Overall, this study (i) discloses the putative protein O-mycoloylome for the first time, (ii) yields new insights into the undercharacterized proteome of the mycomembrane, which is a hallmark of important pathogens (e.g., Corynebacterium diphtheriae, Mycobacterium tuberculosis), and (iii) provides generally applicable chemical strategies for the proteomic analysis of protein lipidation.
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Affiliation(s)
- Nicholas Banahene
- Department
of Chemistry and Biochemistry, Central Michigan
University, Mount
Pleasant, Michigan 48859, United States
- Biochemistry,
Cell, and Molecular Biology Graduate Programs, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
| | - Trenton M. Peters-Clarke
- Department
of Chemistry, University of Wisconsin, Madison, Wisconsin 53562, United States
- Department
of Biomolecular Chemistry, University of
Wisconsin, Madison, Wisconsin 53562, United States
- National
Center for Quantitative Biology of Complex Systems, University of Wisconsin, Madison, Wisconsin 53562, United States
| | - Kyle J. Biegas
- Department
of Chemistry and Biochemistry, Central Michigan
University, Mount
Pleasant, Michigan 48859, United States
- Biochemistry,
Cell, and Molecular Biology Graduate Programs, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
| | - Evgenia Shishkova
- Department
of Biomolecular Chemistry, University of
Wisconsin, Madison, Wisconsin 53562, United States
- National
Center for Quantitative Biology of Complex Systems, University of Wisconsin, Madison, Wisconsin 53562, United States
| | - Elizabeth M. Hart
- Department
of Microbiology, Harvard Medical School, Boston, Massachusetts 02115 United States
- Howard
Hughes Medical Institute, Chevy
Chase, Maryland 20815, United States
| | - Amelia C. McKitterick
- Department
of Microbiology, Harvard Medical School, Boston, Massachusetts 02115 United States
- Howard
Hughes Medical Institute, Chevy
Chase, Maryland 20815, United States
| | - Nikolas H. Kambitsis
- Department
of Chemistry and Biochemistry, Central Michigan
University, Mount
Pleasant, Michigan 48859, United States
| | - Ulysses G. Johnson
- Department
of Chemistry and Biochemistry, Central Michigan
University, Mount
Pleasant, Michigan 48859, United States
- Biochemistry,
Cell, and Molecular Biology Graduate Programs, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
| | - Thomas G. Bernhardt
- Department
of Microbiology, Harvard Medical School, Boston, Massachusetts 02115 United States
- Howard
Hughes Medical Institute, Chevy
Chase, Maryland 20815, United States
| | - Joshua J. Coon
- Department
of Chemistry, University of Wisconsin, Madison, Wisconsin 53562, United States
- Department
of Biomolecular Chemistry, University of
Wisconsin, Madison, Wisconsin 53562, United States
- National
Center for Quantitative Biology of Complex Systems, University of Wisconsin, Madison, Wisconsin 53562, United States
- Morgridge
Institute for Research, Madison, Wisconsin 53562, United States
| | - Benjamin M. Swarts
- Department
of Chemistry and Biochemistry, Central Michigan
University, Mount
Pleasant, Michigan 48859, United States
- Biochemistry,
Cell, and Molecular Biology Graduate Programs, Central Michigan University, Mount
Pleasant, Michigan 48859, United States
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3
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Zhang Z, Li X, Cao C. Octanoic acid-rich enteral nutrition attenuated hypercatabolism through the acylated ghrelin-POMC pathway in endotoxemic rats. Nutrition 2024; 119:112329. [PMID: 38215672 DOI: 10.1016/j.nut.2023.112329] [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: 10/09/2023] [Revised: 12/02/2023] [Accepted: 12/12/2023] [Indexed: 01/14/2024]
Abstract
OBJECTIVES Metabolic disorders and no response to intravenous nutrition because of sepsis have been urgent problems for clinical nutrition support. Enteral nutrition (EN) has been an important clinical therapeutic measure in septic patients; however, simple EN has not demonstrated good performance. This study aimed to investigate the effects of different concentrations of octanoic acid (OA)-rich EN on hypercatabolism in endotoxemic rats and test whether OA-rich EN could attenuate hypercatabolism through the acylated ghrelin-proopiomelanocortin (POMC) pathway. METHODS Rats were randomly divided into six groups: sham, lipopolysaccharide (LPS), LPS + EN and LPS + EN + OA (0.25, 0.5, and 1 g/kg, respectively) groups to investigate the effects of different concentrations of OA-rich EN on hypercatabolism in endotoxemic rats. The rats were then randomly divided into four groups: sham, LPS, LPS + OA, and LPS + OA + Go-CoA-Tat, to test whether OA-rich EN attenuated hypercatabolism through the acylated ghrelin-POMC pathway. Rats received nutrition support via a gastric tube for 3 d (100 kcal/kg daily). Insulin resistance, muscle protein synthesis and atrophy, inflammatory cytokines, ghrelin in circulation and hypothalamus, ghrelin O-acyltransferase (GOAT), and the adenosine 5'-monophosphate-activated protein kinase (AMPK)-autophagy-POMC pathway were measured. RESULTS Compared with simple EN, OA-rich EN promoted the acylation of ghrelin in a dose-dependent manner and attenuated POMC-mediated hypercatabolism in endotoxemic rats. Inhibition of GOAT activity decreased the level of acylated ghrelin and aggravated POMC-mediated hypercatabolism conferred by OA-rich EN. CONCLUSIONS OA-rich EN could increase the level of acylated ghrelin and attenuate hypercatabolism through the acylated ghrelin-POMC pathway compared with simple EN in endotoxemic rats.
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Affiliation(s)
- Zihao Zhang
- Department of General Surgery, the Second Affiliated Hospital of Soochow University, Suzhou, China; Department of Anesthesiology, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaohua Li
- Department of General Surgery, the Second Affiliated Hospital of Soochow University, Suzhou, China; Department of Thyroid and Breast Surgery, Suzhou Wuzhong People's Hospital, Suzhou, China
| | - Chun Cao
- Department of General Surgery, the Second Affiliated Hospital of Soochow University, Suzhou, China.
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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.
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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
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5
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Sarkar K, Das B, Das RK. Discovery of new oxadiazolo pyridine derivatives as potent ghrelin O-acyltransferase inhibitors using molecular modeling techniques. In Silico Pharmacol 2023; 11:35. [PMID: 37954893 PMCID: PMC10632319 DOI: 10.1007/s40203-023-00167-z] [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: 02/16/2023] [Accepted: 10/04/2023] [Indexed: 11/14/2023] Open
Abstract
Diabesity is a major global health concern, and ghrelin O-acyltransferase (GOAT) acts as an important target for the development of new inhibitors of this disease. The present work highlights a detailed QSAR study using QSARINS software, which provides an excellent model equation using descriptors. Here, the best model equation developed has two variables, namely MLFER_E and XlogP, with statistical parameters R2 = 0.8433, LOF = 0.0793, CCCtr = 0.915, Q2LOO = 0.8303, Q2LMO = 0.8275, CCCcv = 0.9081, R2ext = 0.7712, and CCCext = 0.8668. A higher correlation of the key structural fragments with activity is validated by the developed QSAR model. Furthermore, molecular docking helped us identify the binding interactions. Thirty four new molecules with better predicted biological activity (pIC50) were designed. The binding energy of four compounds have shown higher binding activity into the membrane protein (PDB Id: 6BUG). Molecular dynamics simulation has established the stability of the protein-ligand complex over 100 ns. DFT and ADME-toxicity analyses also confirmed their drug-like properties. Based on our findings, we report that these new oxadiazolo pyridine derivatives lead to the development of potent candidates for further development. Graphical abstract METTL3-mediated HOTAIRM1 promotes vasculogenic mimicry in glioma via regulating IGFBP2 expression. METTL3 expression is high in glioma cells and tissues that stabilize and enhance HOTAIRM1 expression. This HOTAIRM1 then interacts with IGFBP2 which in turn promotes glioma cell malignancy and vasculogenic mimicry (VM) formation, thus providing a new direction for glioma therapy. Supplementary Information The online version contains supplementary material available at 10.1007/s40203-023-00167-z.
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Affiliation(s)
- Kaushik Sarkar
- Department of Chemistry, University of North Bengal, Darjeeling, 734013 West Bengal India
| | - Bipasha Das
- Department of Chemistry, University of North Bengal, Darjeeling, 734013 West Bengal India
| | - Rajesh Kumar Das
- Department of Chemistry, University of North Bengal, Darjeeling, 734013 West Bengal India
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6
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Fernández-Verdejo R, Mey JT, Ravussin E. Effects of ketone bodies on energy expenditure, substrate utilization, and energy intake in humans. J Lipid Res 2023; 64:100442. [PMID: 37703994 PMCID: PMC10570604 DOI: 10.1016/j.jlr.2023.100442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023] Open
Abstract
The potential of ketogenic approaches to regulate energy balance has recently gained attention since ketones may influence both energy expenditure and energy intake. In this narrative review, we summarized the most relevant evidence about the role of ketosis on energy expenditure, substrate utilization, and energy intake in humans. We considered different strategies to induce ketosis, such as fasting, dietary manipulation, and exogenous ketone sources. In general, ketosis does not have a major influence on energy expenditure but promotes a shift in substrate utilization towards ketone body oxidation. The strategies to induce ketosis by reduction of dietary carbohydrate availability (e.g., ketogenic diets) do not independently influence energy intake, being thus equally effective for weight loss as diets with higher carbohydrate content. In contrast, the intake of medium-chain triglycerides and ketone esters induces ketosis and appears to increase energy expenditure and reduce energy intake in the context of high carbohydrate availability. These latter strategies lead to slightly enhanced weight loss. Unfortunately, distinguishing the effects of the various ketogenic strategies per se from the effects of other physiological responses is not possible with the available human data. Highly controlled, inpatient studies using targeted strategies to isolate the independent effects of ketones are required to adequately address this knowledge gap.
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Affiliation(s)
- Rodrigo Fernández-Verdejo
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA; Laboratorio de Fisiología del Ejercicio y Metabolismo (LABFEM), Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Jacob T Mey
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
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7
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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.
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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
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8
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Coupland CE, Ansell TB, Sansom MSP, Siebold C. Rocking the MBOAT: Structural insights into the membrane bound O-acyltransferase family. Curr Opin Struct Biol 2023; 80:102589. [PMID: 37040671 DOI: 10.1016/j.sbi.2023.102589] [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: 11/10/2022] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 04/13/2023]
Abstract
The membrane-bound O-acyltransferase (MBOAT) superfamily catalyses the transfer of acyl chains to substrates implicated in essential cellular functions. Aberrant function of MBOATs is associated with various diseases and MBOATs are promising drug targets. There has been recent progress in structural characterisation of MBOATs, advancing our understanding of their functional mechanism. Integrating information across the MBOAT family, we characterise a common MBOAT fold and provide a blueprint for substrate and inhibitor engagement. This work provides context for the diverse substrates, mechanisms, and evolutionary relationships of protein and small-molecule MBOATs. Further work should aim to characterise MBOATs, as inherently lipid-associated proteins, within their membrane environment.
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Affiliation(s)
- Claire E Coupland
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - T Bertie Ansell
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
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9
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Pierce MR, Hougland JL. A rising tide lifts all MBOATs: recent progress in structural and functional understanding of membrane bound O-acyltransferases. Front Physiol 2023; 14:1167873. [PMID: 37250116 PMCID: PMC10213974 DOI: 10.3389/fphys.2023.1167873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/19/2023] [Indexed: 05/31/2023] Open
Abstract
Acylation modifications play a central role in biological and physiological processes. Across a range of biomolecules from phospholipids to triglycerides to proteins, introduction of a hydrophobic acyl chain can dramatically alter the biological function and cellular localization of these substrates. Amongst the enzymes catalyzing these modifications, the membrane bound O-acyltransferase (MBOAT) family occupies an intriguing position as the combined substrate selectivities of the various family members span all three classes of these biomolecules. MBOAT-dependent substrates are linked to a wide range of health conditions including metabolic disease, cancer, and neurodegenerative disease. Like many integral membrane proteins, these enzymes have presented challenges to investigation due to their intractability to solubilization and purification. However, over the last several years new solubilization approaches coupled with computational modeling, crystallography, and cryoelectron microscopy have brought an explosion of structural information for multiple MBOAT family members. These studies enable comparison of MBOAT structure and function across members catalyzing modifications of all three substrate classes, revealing both conserved features amongst all MBOATs and distinct architectural features that correlate with different acylation substrates ranging from lipids to proteins. We discuss the methods that led to this renaissance of MBOAT structural investigations, our new understanding of MBOAT structure and implications for catalytic function, and the potential impact of these studies for development of new therapeutics targeting MBOAT-dependent physiological processes.
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Affiliation(s)
- Mariah R. Pierce
- Department of Chemistry, Syracuse University, Syracuse, NY, United States
| | - James L. Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, United States
- Department of Biology, Syracuse University, Syracuse, NY, United States
- BioInspired Syracuse, Syracuse University, Syracuse, NY, United States
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10
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Boudry G, Cahu A, Romé V, Janvier R, Louvois M, Catheline D, Rioux V, Le Huërou-Luron I, Blat S. The ghrelin system follows a precise post-natal development in mini-pigs that is not impacted by dietary medium chain fatty-acids. Front Physiol 2022; 13:1010586. [PMID: 36225304 PMCID: PMC9549131 DOI: 10.3389/fphys.2022.1010586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/13/2022] Open
Abstract
The ghrelin-ghrelin receptor (GHSR1) system is one of the most important mechanisms regulating food intake and energy balance. To be fully active, ghrelin is acylated with medium-chain fatty acids (MCFA) through the ghrelin-O-acetyl transferase (GOAT). Several studies reported an impact of dietary MCFA on ghrelin acylation in adults. Our study aimed at describing early post-natal development of the ghrelin system in mini-pigs as a model of human neonates and evaluating the impact of dietary MCFA. Suckled mini-pigs were sacrificed at post-natal day (PND) 0, 2, 5, and 10 or at adult stage. In parallel, other mini-pigs were fed from birth to PND10 a standard or a dairy lipid-enriched formula with increased MCFA concentration (DL-IF). Plasma ghrelin transiently peaked at PND2, with no variation of the acylated fraction except in adults where it was greater than during the neonatal period. Levels of mRNA coding pre-proghrelin (GHRL) and GOAT in the antrum did not vary during the post-natal period but dropped in adults. Levels of antral pcsk1/3 (cleaving GHRL into ghrelin) mRNA decreased significantly with age and was negatively correlated with plasma acylated, but not total, ghrelin. Hypothalamic ghsr1 mRNA did not vary in neonates but increased in adults. The DL-IF formula enriched antral tissue with MCFA but did not impact the ghrelin system. In conclusion, the ghrelin maturation enzyme PCSK1/3 gene expression exhibited post-natal modifications parallel to transient variations in circulating plasma ghrelin level in suckling piglets but dietary MCFA did not impact this post-natal development.
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Affiliation(s)
- Gaëlle Boudry
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
- *Correspondence: Gaëlle Boudry,
| | - Armelle Cahu
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
| | - Véronique Romé
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
| | - Régis Janvier
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
| | - Margaux Louvois
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
| | - Daniel Catheline
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
- Institut Agro, Rennes, France
| | - Vincent Rioux
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
- Institut Agro, Rennes, France
| | | | - Sophie Blat
- Institut Numecan, INRAE, INSERM, Univ Rennes, Saint-Gilles-Rennes, France
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11
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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.
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12
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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.
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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
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13
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In Search of Small Molecules That Selectively Inhibit MBOAT4. Molecules 2021; 26:molecules26247599. [PMID: 34946685 PMCID: PMC8709388 DOI: 10.3390/molecules26247599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 01/31/2023] Open
Abstract
Ghrelin is a 28-residue peptide hormone produced by stomach P/D1 cells located in oxyntic glands of the fundus mucosa. Post-translational octanoylation of its Ser-3 residue, catalyzed by MBOAT4 (aka ghrelin O-acyl transferase (GOAT)), is essential for the binding of the hormone to its receptor in target tissues. Physiological roles of acyl ghrelin include the regulation of food intake, growth hormone secretion from the pituitary, and inhibition of insulin secretion from the pancreas. Here, we describe a medicinal chemistry campaign that led to the identification of small lipopeptidomimetics that inhibit GOAT in vitro. These molecules compete directly for substrate binding. We further describe the synthesis of heterocyclic inhibitors that compete at the acyl coenzyme A binding site.
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14
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Gao X, Mazière AD, Beard R, Klumperman J, Hannoush RN. Fatty acylation enhances the cellular internalization and cytosolic distribution of a cystine-knot peptide. iScience 2021; 24:103220. [PMID: 34712919 PMCID: PMC8529511 DOI: 10.1016/j.isci.2021.103220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/14/2021] [Accepted: 09/30/2021] [Indexed: 02/07/2023] Open
Abstract
Delivering peptides into cells could open up possibilities for targeting intracellular proteins. Although fatty acylation of peptide therapeutics improves their systemic half-life, it remains unclear how it influences their cellular uptake. Here, we demonstrate that a fatty acylated peptide exhibits enhanced cellular internalization and cytosolic distribution compared to the un-acylated version. By using a cystine-knot peptide as a model system, we report an efficient strategy for site-specific conjugation of fatty acids. Peptides modified with fatty acids of different chain lengths entered cells through clathrin-mediated and macropinocytosis pathways. The cellular uptake was mediated by the length of the hydrocarbon chain, with myristic acid conjugates displaying the highest distribution across the cytoplasm including the cytosol, and endomembranes of the ER, Golgi and mitochondria. Our studies demonstrate how fatty acylation improves the cellular uptake of peptides, and lay the groundwork for future development of bioactive peptides with enhanced intracellular distribution. A synthetic strategy comprises site-specific conjugation of fatty acids to peptides Fatty acylation of a peptide enhances its cellular uptake and cytosolic distribution Myristoylated peptides display a high cytoplasmic distribution Fatty acylated peptides are internalized via multiple endocytic routes
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Affiliation(s)
- Xinxin Gao
- Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA
| | - Ann De Mazière
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rhiannon Beard
- Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA
| | - Judith Klumperman
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rami N Hannoush
- Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA
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15
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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.
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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
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16
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Stoyanova I, Lutz D. Ghrelin-Mediated Regeneration and Plasticity After Nervous System Injury. Front Cell Dev Biol 2021; 9:595914. [PMID: 33869167 PMCID: PMC8046019 DOI: 10.3389/fcell.2021.595914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
The nervous system is highly vulnerable to different factors which may cause injury followed by an acute or chronic neurodegeneration. Injury involves a loss of extracellular matrix integrity, neuronal circuitry disintegration, and impairment of synaptic activity and plasticity. Application of pleiotropic molecules initiating extracellular matrix reorganization and stimulating neuronal plasticity could prevent propagation of the degeneration into the tissue surrounding the injury. To find an omnipotent therapeutic molecule, however, seems to be a fairly ambitious task, given the complex demands of the regenerating nervous system that need to be fulfilled. Among the vast number of candidates examined so far, the neuropeptide and hormone ghrelin holds within a very promising therapeutic potential with its ability to cross the blood-brain barrier, to balance metabolic processes, and to stimulate neurorepair and neuroactivity. Compared with its well-established systemic effects in treatment of metabolism-related disorders, the therapeutic potential of ghrelin on neuroregeneration upon injury has received lesser appreciation though. Here, we discuss emerging concepts of ghrelin as an omnipotent player unleashing developmentally related molecular cues and morphogenic cascades, which could attenuate and/or counteract acute and chronic neurodegeneration.
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Affiliation(s)
- Irina Stoyanova
- Department of Anatomy and Cell Biology, Medical University Varna, Varna, Bulgaria
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
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17
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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.
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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
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18
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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.
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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
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19
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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.
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Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
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20
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Miki K, Kitada S, Miki M, Hui SP, Shrestha R, Yoshimura K, Tsujino K, Kagawa H, Oshitani Y, Kida H, Maekura R, Kangawa K. A phase II, open-label clinical trial on the combination therapy with medium-chain triglycerides and ghrelin in patients with chronic obstructive pulmonary disease. J Physiol Sci 2019; 69:969-979. [PMID: 31595463 PMCID: PMC10716959 DOI: 10.1007/s12576-019-00716-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 09/19/2019] [Indexed: 12/20/2022]
Abstract
The aim of this study was to investigate the effect of activated ghrelin with dietary octanoic acids or medium-chain triglyceride (MCT) administration to underweight patient with chronic obstructive pulmonary disease (COPD). Eleven severe and very severe COPD patients received a 5-day treatment with edible MCT. Sequentially, 10 patients received a 3-week combination treatment with MCT and intravenous acyl ghrelin. Five-day MCT treatment increased endogenous acyl ghrelin (p = 0.0049), but the total ghrelin level was unchanged. MCT-ghrelin combination treatment improved the peak oxygen uptake (p = 0.0120) during whole treatment course. This effect was attributed to the resultant improvements in cardiac function by O2 pulse, and to the difference between inspired and expired oxygen concentration rather than minute ventilation. Addition of dietary MCT to ghrelin treatment improved the aerobic capacity of underweight COPD patients, likely by mechanisms of increased O2 delivery through improvements in primary cardiocirculatory and muscular crosstalk.
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Affiliation(s)
- Keisuke Miki
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan.
| | - Seigo Kitada
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Mari Miki
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Shu-Ping Hui
- Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi-5, Sapporo, Japan
| | - Rojeet Shrestha
- Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi-5, Sapporo, Japan
| | - Kenji Yoshimura
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Kazuyuki Tsujino
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Hiroyuki Kagawa
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Yohei Oshitani
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Hiroshi Kida
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
| | - Ryoji Maekura
- Department of Respiratory Medicine, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka, Osaka, 560-8552, Japan
- Graduate School of Health Care Sciences, Jikei Institute, Miyahara 1-2-8, Yodogawa-ku, Osaka, Japan
| | - Kenji Kangawa
- National Cerebral and Cardiovascular Center Research Institute, 6-1, Kishibeshinmachi, Suita, Japan
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21
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Structure and dynamics of G protein-coupled receptor-bound ghrelin reveal the critical role of the octanoyl chain. Proc Natl Acad Sci U S A 2019; 116:17525-17530. [PMID: 31416915 DOI: 10.1073/pnas.1905105116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Ghrelin plays a central role in controlling major biological processes. As for other G protein-coupled receptor (GPCR) peptide agonists, the structure and dynamics of ghrelin bound to its receptor remain obscure. Using a combination of solution-state NMR and molecular modeling, we demonstrate that binding to the growth hormone secretagogue receptor is accompanied by a conformational change in ghrelin that structures its central region, involving the formation of a well-defined hydrophobic core. By comparing its acylated and nonacylated forms, we conclude that the ghrelin octanoyl chain is essential to form the hydrophobic core and promote access of ghrelin to the receptor ligand-binding pocket. The combination of coarse-grained molecular dynamics studies and NMR should prove useful in improving our mechanistic understanding of the complex conformational space explored by a natural peptide agonist when binding to its GPCR. Such information should also facilitate the design of new ghrelin receptor-selective drugs.
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22
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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.
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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
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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.
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24
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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.
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Affiliation(s)
| | | | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA.
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25
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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.
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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.
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26
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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.
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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.
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27
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 282] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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28
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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.
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Affiliation(s)
| | | | - James L Hougland
- a Department of Chemistry , Syracuse University , Syracuse , NY , USA
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29
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Is Ghrelin Synthesized in the Central Nervous System? Int J Mol Sci 2017; 18:ijms18030638. [PMID: 28294994 PMCID: PMC5372651 DOI: 10.3390/ijms18030638] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 02/06/2023] Open
Abstract
Ghrelin is an octanoylated peptide that acts via its specific receptor, the growth hormone secretagogue receptor type 1a (GHSR-1a), and regulates a vast variety of physiological functions. It is well established that ghrelin is predominantly synthesized by a distinct population of endocrine cells located within the gastric oxyntic mucosa. In addition, some studies have reported that ghrelin could also be synthesized in some brain regions, such as the hypothalamus. However, evidences of neuronal production of ghrelin have been inconsistent and, as a consequence, it is still as a matter of debate if ghrelin can be centrally produced. Here, we provide a comprehensive review and discussion of the data supporting, or not, the notion that the mammalian central nervous system can synthetize ghrelin. We conclude that no irrefutable and reproducible evidence exists supporting the notion that ghrelin is synthetized, at physiologically relevant levels, in the central nervous system of adult mammals.
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30
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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.
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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
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31
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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.
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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
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32
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Effect of preduodenal lipase inhibition in suckling rats on dietary octanoic acid (C8:0) gastric absorption and plasma octanoylated ghrelin concentration. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1111-1120. [DOI: 10.1016/j.bbalip.2016.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 02/06/2023]
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33
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Eslami Z, Ghassempour A, Aboul-Enein HY. Recent developments in liquid chromatography-mass spectrometry analyses of ghrelin and related peptides. Biomed Chromatogr 2016; 31. [DOI: 10.1002/bmc.3796] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/18/2016] [Accepted: 07/21/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Zahra Eslami
- Faculty of Phytochemistry, Medicinal Plants and Drug Research Institute; Shahid Beheshti University, Evin; Tehran Iran
| | - Alireza Ghassempour
- Faculty of Phytochemistry, Medicinal Plants and Drug Research Institute; Shahid Beheshti University, Evin; Tehran Iran
| | - Hassan Y. Aboul-Enein
- Pharmaceutical and Medicinal Chemistry Department; Pharmaceutical and Drug Industries Research Division; National Research Center, Dokki; Giza 12622 Egypt
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34
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Resh MD. Fatty acylation of proteins: The long and the short of it. Prog Lipid Res 2016; 63:120-31. [PMID: 27233110 DOI: 10.1016/j.plipres.2016.05.002] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/19/2016] [Accepted: 05/21/2016] [Indexed: 12/22/2022]
Abstract
Long, short and medium chain fatty acids are covalently attached to hundreds of proteins. Each fatty acid confers distinct biochemical properties, enabling fatty acylation to regulate intracellular trafficking, subcellular localization, protein-protein and protein-lipid interactions. Myristate and palmitate represent the most common fatty acid modifying groups. New insights into how fatty acylation reactions are catalyzed, and how fatty acylation regulates protein structure and function continue to emerge. Myristate is typically linked to an N-terminal glycine, but recent studies reveal that lysines can also be myristoylated. Enzymes that remove N-terminal myristoyl-glycine or myristate from lysines have now been identified. DHHC proteins catalyze S-palmitoylation, but the mechanisms that regulate substrate recognition by individual DHHC family members remain to be determined. New studies continue to reveal thioesterases that remove palmitate from S-acylated proteins. Another area of rapid expansion is fatty acylation of the secreted proteins hedgehog, Wnt and Ghrelin, by Hhat, Porcupine and GOAT, respectively. Understanding how these membrane bound O-acyl transferases recognize their protein and fatty acyl CoA substrates is an active area of investigation, and is punctuated by the finding that these enzymes are potential drug targets in human diseases.
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Affiliation(s)
- Marilyn D Resh
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 143, New York, NY 10075, United States.
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35
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Lemarié F, Beauchamp E, Legrand P, Rioux V. Revisiting the metabolism and physiological functions of caprylic acid (C8:0) with special focus on ghrelin octanoylation. Biochimie 2015; 120:40-8. [PMID: 26253695 DOI: 10.1016/j.biochi.2015.08.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/01/2015] [Indexed: 12/22/2022]
Abstract
Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils like coconut oil are natural sources of dietary C8:0 but higher intakes of this fatty acid can be provided with MCT (Medium-Chain Triglycerides) oil that consists in 75% of C8:0. MCFAs have physical and metabolic properties that are distinct from those of long-chain saturated fatty acids (LCFAs ≥ 12 carbons). Beneficial physiological effects of dietary C8:0 have been studied for a long time and MCT oil has been used as a special energy source for patients suffering from pancreatic insufficiency, impaired lymphatic chylomicron transport and fat malabsorption. More recently, caprylic acid was also shown to acylate 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. This review tries to highlight the discrepancy between the formerly described beneficial effects of dietary MCFAs on body weight loss and the C8:0 newly reported effect on appetite stimulation via ghrelin octanoylation. The subsequent aim of this review is to demonstrate the relevance of carrying out further studies to better understand the physiological functions of this particular fatty acid.
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Affiliation(s)
- Fanny Lemarié
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, INRA USC 1378, Rennes, France
| | - Erwan Beauchamp
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, INRA USC 1378, Rennes, France
| | - Philippe Legrand
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, INRA USC 1378, Rennes, France
| | - Vincent Rioux
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, INRA USC 1378, Rennes, France.
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36
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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.
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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.
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37
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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.
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38
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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.
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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,
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