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Bouyakdan K, Manceau R, Robb JL, Rodaros D, Fulton S, Alquier T. Role of astroglial ACBP in energy metabolism flexibility and feeding responses to metabolic challenges in male mice. J Neuroendocrinol 2022; 34:e13218. [PMID: 36471907 DOI: 10.1111/jne.13218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/26/2022] [Accepted: 11/10/2022] [Indexed: 11/19/2022]
Abstract
Acyl-CoA binding protein (ACBP), also known as diazepam binding inhibitor (DBI), has recently emerged as a hypothalamic and brainstem gliopeptide regulating energy balance. Previous work has shown that the ACBP-derived octadecaneuropeptide exerts strong anorectic action via proopiomelanocortin (POMC) neuron activation and the melanocortin-4 receptor. Importantly, targeted ACBP loss-of-function in astrocytes promotes hyperphagia and diet-induced obesity while its overexpression in arcuate astrocytes reduces feeding and body weight. Despite this knowledge, the role of astroglial ACBP in adaptive feeding and metabolic responses to acute metabolic challenges has not been investigated. Using different paradigms, we found that ACBP deletion in glial fibrillary acidic protein (GFAP)-positive astrocytes does not affect weight loss when obese male mice are transitioned from a high fat diet to a chow diet, nor metabolic parameters in mice fed with a normal chow diet (e.g., energy expenditure, body temperature) during fasting, cold exposure and at thermoneutrality. In contrast, astroglial ACBP deletion impairs meal pattern and feeding responses during refeeding after a fast and during cold exposure, thereby showing that ACBP is required to stimulate feeding in states of increased energy demand. These findings challenge the general view that astroglial ACBP exerts anorectic effects and suggest that regulation of feeding by ACBP is dependent on metabolic status.
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Affiliation(s)
- Khalil Bouyakdan
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
| | - Romane Manceau
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
| | - Josephine L Robb
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
| | - Demetra Rodaros
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
| | - Stephanie Fulton
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
| | - Thierry Alquier
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal Diabetes Research Center, and Departments of Medicine and Neurosciences and Nutrition, Université de Montréal, Montréal, Quebec, Canada
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Sun EW, Iepsen EW, Pezos N, Lumsden AL, Martin AM, Schober G, Isaacs NJ, Rayner CK, Nguyen NQ, de Fontgalland D, Rabbitt P, Hollington P, Wattchow DA, Hansen T, Holm JC, Liou AP, Jackson VM, Torekov SS, Young RL, Keating DJ. A Gut-Intrinsic Melanocortin Signaling Complex Augments L-Cell Secretion in Humans. Gastroenterology 2021; 161:536-547.e2. [PMID: 33848536 DOI: 10.1053/j.gastro.2021.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/04/2021] [Accepted: 04/06/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Hypothalamic melanocortin 4 receptors (MC4R) are a key regulator of energy homeostasis. Brain-penetrant MC4R agonists have failed, as concentrations required to suppress food intake also increase blood pressure. However, peripherally located MC4R may also mediate metabolic benefits of MC4R activation. Mc4r transcript is enriched in mouse enteroendocrine L cells and peripheral administration of the endogenous MC4R agonist, α-melanocyte stimulating hormone (α-MSH), triggers the release of the anorectic hormones Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) in mice. This study aimed to determine whether pathways linking MC4R and L-cell secretion exist in humans. DESIGN GLP-1 and PYY levels were assessed in body mass index-matched individuals with or without loss-of-function MC4R mutations following an oral glucose tolerance test. Immunohistochemistry was performed on human intestinal sections to characterize the mucosal MC4R system. Static incubations with MC4R agonists were carried out on human intestinal epithelia, GLP-1 and PYY contents of secretion supernatants were assayed. RESULTS Fasting PYY levels and oral glucose-induced GLP-1 secretion were reduced in humans carrying a total loss-of-function MC4R mutation. MC4R was localized to L cells and regulates GLP-1 and PYY secretion from ex vivo human intestine. α-MSH immunoreactivity in the human intestinal epithelia was predominantly localized to L cells. Glucose-sensitive mucosal pro-opiomelanocortin cells provide a local source of α-MSH that is essential for glucose-induced GLP-1 secretion in small intestine. CONCLUSION Our findings describe a previously unidentified signaling nexus in the human gastrointestinal tract involving α-MSH release and MC4R activation on L cells in an autocrine and paracrine fashion. Outcomes from this study have direct implications for targeting mucosal MC4R to treat human metabolic disorders.
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Affiliation(s)
- Emily W Sun
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Eva W Iepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Nektaria Pezos
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Amanda L Lumsden
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Alyce M Martin
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Gudrun Schober
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Nichole J Isaacs
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Christopher K Rayner
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Nam Q Nguyen
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Torben Hansen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens-Christian Holm
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark; Department of Pediatrics, Holbæk University Hospital, Holbæk, Denmark
| | - Alice P Liou
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - V Margaret Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Richard L Young
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia.
| | - Damien J Keating
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia.
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Smitka K, Prochazkova P, Roubalova R, Dvorak J, Papezova H, Hill M, Pokorny J, Kittnar O, Bilej M, Tlaskalova-Hogenova H. Current Aspects of the Role of Autoantibodies Directed Against Appetite-Regulating Hormones and the Gut Microbiome in Eating Disorders. Front Endocrinol (Lausanne) 2021; 12:613983. [PMID: 33953692 PMCID: PMC8092392 DOI: 10.3389/fendo.2021.613983] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 03/09/2021] [Indexed: 12/12/2022] Open
Abstract
The equilibrium and reciprocal actions among appetite-stimulating (orexigenic) and appetite-suppressing (anorexigenic) signals synthesized in the gut, brain, microbiome and adipose tissue (AT), seems to play a pivotal role in the regulation of food intake and feeding behavior, anxiety, and depression. A dysregulation of mechanisms controlling the energy balance may result in eating disorders such as anorexia nervosa (AN) and bulimia nervosa (BN). AN is a psychiatric disease defined by chronic self-induced extreme dietary restriction leading to an extremely low body weight and adiposity. BN is defined as out-of-control binge eating, which is compensated by self-induced vomiting, fasting, or excessive exercise. Certain gut microbiota-related compounds, like bacterial chaperone protein Escherichia coli caseinolytic protease B (ClpB) and food-derived antigens were recently described to trigger the production of autoantibodies cross-reacting with appetite-regulating hormones and neurotransmitters. Gut microbiome may be a potential manipulator for AT and energy homeostasis. Thus, the regulation of appetite, emotion, mood, and nutritional status is also under the control of neuroimmunoendocrine mechanisms by secretion of autoantibodies directed against neuropeptides, neuroactive metabolites, and peptides. In AN and BN, altered cholinergic, dopaminergic, adrenergic, and serotonergic relays may lead to abnormal AT, gut, and brain hormone secretion. The present review summarizes updated knowledge regarding the gut dysbiosis, gut-barrier permeability, short-chain fatty acids (SCFA), fecal microbial transplantation (FMT), blood-brain barrier permeability, and autoantibodies within the ghrelin and melanocortin systems in eating disorders. We expect that the new knowledge may be used for the development of a novel preventive and therapeutic approach for treatment of AN and BN.
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Affiliation(s)
- Kvido Smitka
- First Faculty of Medicine, Institute of Physiology, Charles University, Prague, Czechia
- First Faculty of Medicine, Institute of Pathological Physiology, Charles University, Prague, Czechia
- *Correspondence: Kvido Smitka,
| | - Petra Prochazkova
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Radka Roubalova
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Jiri Dvorak
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Hana Papezova
- Psychiatric Clinic, Eating Disorder Center, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Martin Hill
- Steroid Hormone and Proteofactors Department, Institute of Endocrinology, Prague, Czechia
| | - Jaroslav Pokorny
- First Faculty of Medicine, Institute of Physiology, Charles University, Prague, Czechia
| | - Otomar Kittnar
- First Faculty of Medicine, Institute of Physiology, Charles University, Prague, Czechia
| | - Martin Bilej
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Helena Tlaskalova-Hogenova
- Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
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Kuhre RE, Modvig IM, Jepsen SL, Kizilkaya HS, Bæch-Laursen C, Smith CA, Reimann F, Gribble FM, Rosenkilde MM, Holst JJ. L-Cell Expression of Melanocortin-4-Receptor Is Marginal in Most of the Small Intestine in Mice and Humans and Direct Stimulation of Small Intestinal Melanocortin-4-Receptors in Mice and Rats Does Not Affect GLP-1 Secretion. Front Endocrinol (Lausanne) 2021; 12:690387. [PMID: 34421821 PMCID: PMC8375664 DOI: 10.3389/fendo.2021.690387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/18/2021] [Indexed: 11/17/2022] Open
Abstract
The molecular sensors underlying nutrient-stimulated GLP-1 secretion are currently being investigated. Peripheral administration of melanocortin-4 receptor (MC4R) agonists have been reported to increase GLP-1 plasma concentrations in mice and humans but it is unknown whether this effect results from a direct effect on the GLP-1 secreting L-cells in the intestine, from other effects in the intestine or from extra-intestinal effects. We investigated L-cell expression of MC4R in mouse and human L-cells by reanalyzing publicly available RNA sequencing databases (mouse and human) and by RT-qPCR (mouse), and assessed whether administration of MC4R agonists to a physiologically relevant gut model, isolated perfused mouse and rat small intestine, would stimulate GLP-1 secretion or potentiate glucose-stimulated secretion. L-cell MC4R expression was low in mouse duodenum and hardly detectable in the ileum and MC4R expression was hardly detectable in human L-cells. In isolated perfused mouse and rat intestine, neither intra-luminal nor intra-arterial administration of NDP-alpha-MSH, a potent MC4R agonist, had any effect on GLP-1 secretion (P ≥0.98, n = 5-6) from the upper or lower-half of the small intestine in mice or in the lower half in rats. Furthermore, HS014-an often used MC4R antagonist, which we found to be a partial agonist-did not affect the glucose-induced GLP-1 response in the rat, P = 0.62, n = 6). Studies on transfected COS7-cells confirmed bioactivity of the used compounds and that concentrations employed were well within in the effective range. Our combined data therefore suggest that MC4R-activated GLP-1 secretion in rodents either exclusively occurs in the colon or involves extra-intestinal signaling.
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Affiliation(s)
- Rune E. Kuhre
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Obesity Pharmacology, Novo Nordisk, Måløv, Denmark
- *Correspondence: Rune E. Kuhre, ; Jens J. Holst,
| | - Ida M. Modvig
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara L. Jepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hüsün S. Kizilkaya
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cecilie Bæch-Laursen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christopher A. Smith
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Frank Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Fiona M. Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Mette M. Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Rune E. Kuhre, ; Jens J. Holst,
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Nieto JE, Casanova I, Serna-Ojeda JC, Graue-Hernández EO, Quintana G, Salazar A, Jiménez-Martinez MC. Increased Expression of TLR4 in Circulating CD4+T Cells in Patients with Allergic Conjunctivitis and In Vitro Attenuation of Th2 Inflammatory Response by Alpha-MSH. Int J Mol Sci 2020; 21:E7861. [PMID: 33114004 DOI: 10.3390/ijms21217861] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/17/2020] [Accepted: 10/21/2020] [Indexed: 12/24/2022] Open
Abstract
Ocular allergic diseases are frequently seen in ophthalmological clinical practice. Immunological damage is mediated by a local Th2 inflammatory microenvironment, accompanied by changes in circulating cell subsets, with more effector cells and fewer T regulatory cells (Tregs). This study aimed to evaluate the involvement of toll-like receptor 4 (TLR4) and α-melanocyte stimulating hormone (α-MSH) in the immune regulation associated with perennial allergic conjunctivitis (PAC). We performed an Ag-specific stimulation during 72 h of culturing with or without lipopolysaccharide (LPS) or α-MSH in peripheral blood mononuclear cells (PBMC), analyzing the cell subsets and cytokines induced by the stimuli. We also determined α-MSH in tear samples from healthy donors (HD) or PAC patients. Our findings demonstrate an immunological dysregulation characterized by an increased frequency of CD4+TLR4+ in the PBMC of patients with PAC, compared to HD. Most of these CD4+TLR4+ cells were also CD25+, and when α-MSH was added to the culture, the percentage of CD4+CD25+FoxP3+ increased significantly, while the percentage of CD69+ cells and cytokines IL-4 and IL-6 were significantly decreased. In tears, we found an increased concentration of α-MSH in PAC patients, compared with HD. These findings indicate a novel mechanism involved in controlling ocular allergic diseases, in which α-MSH diminishes the concentration of IL-6 and IL-4, restoring the frequency of Tregs and down-regulating CD4 activation. Moreover, we demonstrated the involvement of CD4+TLR4+ cells as an effector cell subset in ocular allergy.
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Todorovic A, Lensing CJ, Holder JR, Scott JW, Sorensen NB, Haskell-Luevano C. Discovery of Melanocortin Ligands via a Double Simultaneous Substitution Strategy Based on the Ac-His-dPhe-Arg-Trp-NH 2 Template. ACS Chem Neurosci 2018; 9:2753-2766. [PMID: 29783840 DOI: 10.1021/acschemneuro.8b00181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The melanocortin system regulates an array of diverse physiological functions including pigmentation, feeding behavior, energy homeostasis, cardiovascular regulation, sexual function, and steroidogenesis. Endogenous melanocortin agonist ligands all possess the minimal messaging tetrapeptide sequence His-Phe-Arg-Trp. Based on this endogenous sequence, the Ac-His1-dPhe2-Arg3-Trp4-NH2 tetrapeptide has previously been shown to be a useful scaffold when utilizing traditional positional scanning approaches to modify activity at the various melanocortin receptors (MC1-5R). The study reported herein was undertaken to evaluate a double simultaneous substitution strategy as an approach to further diversify the Ac-His1-dPhe2-Arg3-Trp4-NH2 tetrapeptide with concurrent introduction of natural and unnatural amino acids at positions 1, 2, or 4, as well as an octanoyl residue at the N-terminus. The designed library includes the following combinations: (A) double simultaneous substitution at capping group position (Ac) together with position 1, 2, or 4, (B) double simultaneous substitution at positions 1 and 2, (C) double simultaneous substitution at positions 1 and 4, and (D) double simultaneous substitution at positions 2 and 4. Several lead ligands with unique pharmacologies were discovered in the current study including antagonists targeting the neuronal mMC3R with minimal agonist activity and ligands with selective profiles for the various melanocortin subtypes. The results suggest that the double simultaneous substitution strategy is a suitable approach in altering melanocortin receptor potency or selectivity or converting agonists into antagonists and vice versa.
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Affiliation(s)
- Aleksandar Todorovic
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Cody J. Lensing
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jerry Ryan Holder
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Joseph W. Scott
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Nicholas B. Sorensen
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Grässel S, Muschter D. Do Neuroendocrine Peptides and Their Receptors Qualify as Novel Therapeutic Targets in Osteoarthritis? Int J Mol Sci 2018; 19:E367. [PMID: 29373492 DOI: 10.3390/ijms19020367] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 01/15/2023] Open
Abstract
Joint tissues like synovium, articular cartilage, meniscus and subchondral bone, are targets for neuropeptides. Resident cells of these tissues express receptors for various neuroendocrine-derived peptides including proopiomelanocortin (POMC)-derived peptides, i.e., α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropin (ACTH) and β-endorphin (β-ED), and sympathetic neuropeptides like vasoactive intestinal peptide (VIP) and neuropeptide y (NPY). Melanocortins attained particular attention due to their immunomodulatory and anti-inflammatory effects in several tissues and organs. In particular, α-MSH, ACTH and specific melanocortin-receptor (MCR) agonists appear to have promising anti-inflammatory actions demonstrated in animal models of experimentally induced arthritis and osteoarthritis (OA). Sympathetic neuropeptides have obtained increasing attention as they have crucial trophic effects that are critical for joint tissue and bone homeostasis. VIP and NPY are implicated in direct and indirect activation of several anabolic signaling pathways in bone and synovial cells. Additionally, pituitary adenylate cyclase-activating polypeptide (PACAP) proved to be chondroprotective and, thus, might be a novel target in OA. Taken together, it appears more and more likely that the anabolic effects of these neuroendocrine peptides or their respective receptor agonists/antagonists may be exploited for the treatment of patients with inflammatory and degenerative joint diseases in the future.
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Abstract
INTRODUCTION Prolylcarboxypeptidase (PrCP) is a serine protease that produces or degrades signaling proteins in several important pathways including the renin-angiotensin system (RAS), kallikrein-kinin system (KKS) and pro-opiomelanocortin (POMC) system. PrCP has the potential to be a therapeutic target for cardiovascular, inflammatory and metabolic diseases. Numerous classes of PrCP inhibitors have been developed by rational drug design and from high-throughput screening hits. These inhibitors have been tested in mouse models to assess their potential as new therapeutics. Areas Covered: This review covers the relevant studies that support PrCP as a target for drug discovery. All the significant patent applications and primary literature concerning the development of PrCP inhibitors are discussed. Expert Opinion: The pathways where PrCP is known to operate are complex and many aspects remain to be characterized. Many potent inhibitors of PrCP have been tested in vivo. The variable results obtained from in vivo studies with PrCP inhibitors suggest that additional understanding of the biochemistry and the required therapeutic inhibitor levels is necessary. Additional fundamental research into the signaling pathways is likely required before the true therapeutic potential of PrCP inhibition will be realized.
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Affiliation(s)
- Thomas H Graham
- a Merck Research Laboratories , Merck & Co., Inc ., Kenilworth , NJ , USA
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Clemson CM, Yost J, Taylor AW. The Role of Alpha-MSH as a Modulator of Ocular Immunobiology Exemplifies Mechanistic Differences between Melanocortins and Steroids. Ocul Immunol Inflamm 2016; 25:179-189. [PMID: 26807874 PMCID: PMC5769144 DOI: 10.3109/09273948.2015.1092560] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Melanocortins are a highly conserved family of peptides and receptors that includes multiple proopiomelanocortin-derived peptides and five defined melanocortin receptors. The melanocortins have an important role in maintaining immune homeostasis and in suppressing inflammation. Within the healthy eye, the melanocortins have a central role in preventing inflammation and maintaining immune privilege. A central mediator of the anti-inflammatory activity is the non-steroidogenic melanocortin peptide alpha-melanocyte stimulating hormone. In this review we summarize the major findings of melanocortin regulation of ocular immunobiology with particular interest in the ability of melanocortin to induce immune tolerance and cytoprotection. The melanocortins have therapeutic potential because their mechanisms of action in regulating immunity are distinctly different from the actions of steroids.
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Affiliation(s)
- Christine M Clemson
- a Autoimmune and Rare Diseases , Mallinckrodt Pharmaceuticals , Hayward , CA , USA
| | - John Yost
- a Autoimmune and Rare Diseases , Mallinckrodt Pharmaceuticals , Hayward , CA , USA
| | - Andrew W Taylor
- b Department of Ophthalmology , Boston University School of Medicine , Boston , MA , USA
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