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Schubert T, Schaaf CP. MAGEL2 (patho-)physiology and Schaaf-Yang syndrome. Dev Med Child Neurol 2024. [PMID: 38950199 DOI: 10.1111/dmcn.16018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 05/19/2024] [Accepted: 06/11/2024] [Indexed: 07/03/2024]
Abstract
Schaaf-Yang syndrome (SYS) is a complex neurodevelopmental disorder characterized by autism spectrum disorder, joint contractures, and profound hypothalamic dysfunction. SYS is caused by variants in MAGEL2, a gene within the Prader-Willi syndrome (PWS) locus on chromosome 15. In this review, we consolidate decades of research on MAGEL2 to elucidate its physiological functions. Moreover, we synthesize current knowledge on SYS, suggesting that while MAGEL2 loss-of-function seems to underlie several SYS and PWS phenotypes, additional pathomechanisms probably contribute to the distinct and severe phenotype observed in SYS. In addition, we highlight recent therapeutic advances and identify promising avenues for future investigation.
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Affiliation(s)
- Tim Schubert
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
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Queen NJ, Huang W, Zou X, Mo X, Cao L. AAV-BDNF gene therapy ameliorates a hypothalamic neuroinflammatory signature in the Magel2-null model of Prader-Willi syndrome. Mol Ther Methods Clin Dev 2023; 31:101108. [PMID: 37766791 PMCID: PMC10520877 DOI: 10.1016/j.omtm.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023]
Abstract
Individuals with Prader-Willi syndrome (PWS) exhibit several metabolic and behavioral abnormalities associated with excessive food-seeking activity. PWS is thought to be driven in part by dysfunctional hypothalamic circuitry and blunted responses to peripheral signals of satiety. Previous work described a hypothalamic transcriptomic signature of individuals with PWS. Notably, PWS patients exhibited downregulation of genes involved in neuronal development and an upregulation of neuroinflammatory genes. Deficiencies of brain-derived neurotrophic factor (BDNF) and its receptor were identified as potential drivers of PWS phenotypes. Our group recently applied an adeno-associated viral (AAV)-BDNF gene therapy within a preclinical PWS model, Magel2-null mice, to improve metabolic and behavioral function. While this proof-of-concept project was promising, it remained unclear how AAV-BDNF was influencing the hypothalamic microenvironment and how its therapeutic effect was mediated. To investigate, we hypothalamically injected AAV-BDNF to wild type and Magel2-null mice and performed mRNA sequencing on hypothalamic tissue. Here, we report that (1) Magel2 deficiency is associated with neuroinflammation in the hypothalamus and (2) AAV-BDNF gene therapy reverses this neuroinflammation. These data newly reveal Magel2-null mice as a valid model of PWS-related neuroinflammation and furthermore suggest that AAV-BDNF may modulate obesity-related neuroinflammatory phenotypes through direct or indirect means.
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Affiliation(s)
- Nicholas J. Queen
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Wei Huang
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Xunchang Zou
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Xiaokui Mo
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Lei Cao
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
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Shi Q, Liu X, Fan X, Wang R, Qi K. Paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids programs offspring leptin expression and gene imprinting in mice. Front Nutr 2022; 9:1043876. [PMID: 36618698 PMCID: PMC9816484 DOI: 10.3389/fnut.2022.1043876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/08/2022] [Indexed: 12/25/2022] Open
Abstract
Background This study determined the effects of the paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids (PUFAs) on leptin expression in the offspring and associated gene imprinting in a mouse model. Methods Three- to four-week-old male C57BL/6J mice (F0) were fed an n-3 PUFA-deficient (n-3 D) diet, a diet with normal n-3 PUFA content (n-3 N; n-6: n-3 = 4.3:1), or a diet with a high n-3 PUFA content (n-3 H; n-6: n-3 = 1.5:1) for 8 weeks. Two subsequent generations were generated by mating F0 and F1 male mice with 10-week-old virgin female C57 BL/6J mice, to produce F1 and F2 offspring. Results Compared to the paternal n-3 D diet, paternal n-3 N and n-3 H diets reduced adipose mRNA expression of leptin (Lep) and its plasma concentrations in juvenile F1 male and female offspring, and adult F1 male and F2 female offspring, with upregulated Lep receptor mRNA expression in the hypothalamus. Meanwhile, paternal n-3 N and n-3 H diets altered the expression of the imprinted genes H19, Igf2, Igf2r, Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10 in the adipose tissue of juvenile and adult F1 males, with almost no effects on F1 females, while more effects were observed in the adult F2 females than F2 males. Principal component analysis verified that Plagl1, Cdkn1c, and Kcnq1ot1 contributed the most to variation in adipose tissue expression in all offspring. Some of these genes (Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10) were altered by the paternal n-3 N and n-3 H diets in the F1 and F2 generation testes as well. Furthermore, adipose Lep expression was positively correlated with expressions of H19, Igf2r, Plagl1, and Kcnq1ot1 in juvenile F1 males and females, negatively correlated with the Kcnq1ot1 expression in adult F1 males, and positively correlated with the Plagl1 expression in adult F2 females. Conclusion These data imply that paternal Plagl1, Cdkn1c, and Kcnq1ot1 might be part of the pathways involved in offspring leptin programming. Therefore, a lower ratio of n-6: n-3 PUFAs, with higher intake of n-3 PUFAs in paternal pre-conception, may help maintain the offspring's optimal leptin pattern in a sex-specific manner through multiple generations, and thereby, be beneficial for the offspring's long-term health.
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Queen NJ, Zou X, Anderson JM, Huang W, Appana B, Komatineni S, Wevrick R, Cao L. Hypothalamic AAV-BDNF gene therapy improves metabolic function and behavior in the Magel2-null mouse model of Prader-Willi syndrome. Mol Ther Methods Clin Dev 2022; 27:131-148. [PMID: 36284766 PMCID: PMC9573893 DOI: 10.1016/j.omtm.2022.09.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/23/2022] [Indexed: 11/25/2022]
Abstract
Individuals with Prader-Willi syndrome (PWS) display developmental delays, cognitive impairment, excessive hunger, obesity, and various behavioral abnormalities. Current PWS treatments are limited to strict supervision of food intake and growth hormone therapy, highlighting the need for new therapeutic strategies. Brain-derived neurotrophic factor (BDNF) functions downstream of hypothalamic feeding circuitry and has roles in energy homeostasis and behavior. In this preclinical study, we assessed the translational potential of hypothalamic adeno-associated virus (AAV)-BDNF gene therapy as a therapeutic for metabolic dysfunction in the Magel2-null mouse model of PWS. To facilitate clinical translation, our BDNF vector included an autoregulatory element allowing for transgene titration in response to the host's physiological needs. Hypothalamic BDNF gene transfer prevented weight gain, decreased fat mass, increased lean mass, and increased relative energy expenditure in female Magel2-null mice. Moreover, BDNF gene therapy improved glucose metabolism, insulin sensitivity, and circulating adipokine levels. Metabolic improvements were maintained through 23 weeks with no adverse behavioral effects, indicating high levels of efficacy and safety. Male Magel2-null mice also responded positively to BDNF gene therapy, displaying improved body composition, insulin sensitivity, and glucose metabolism. Together, these data suggest that regulating hypothalamic BDNF could be effective in the treatment of PWS-related metabolic abnormalities.
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Affiliation(s)
- Nicholas J. Queen
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Xunchang Zou
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Jacqueline M. Anderson
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Wei Huang
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Bhavya Appana
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Suraj Komatineni
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Lei Cao
- Department of Cancer Biology & Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
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Barrea L, Vetrani C, Fintini D, de Alteriis G, Panfili FM, Bocchini S, Verde L, Colao A, Savastano S, Muscogiuri G. Prader-Willi Syndrome in Adults: An Update On Nutritional Treatment and Pharmacological Approach. Curr Obes Rep 2022; 11:263-276. [PMID: 36063285 PMCID: PMC9729321 DOI: 10.1007/s13679-022-00478-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/23/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Prader-Willi syndrome (PWS) is a rare and complex genetic disorder with multiple effects on the metabolic, endocrine, and neurological systems, as well as behavioral and intellectual difficulties. Despite advances in understanding the genetic basis of obesity in PWS, there are conflicting data on its management. Therefore, the present manuscript aims to provide an update on the nutritional treatment and pharmacological approach in adult patients with PWS. RECENT FINDINGS The management of obesity in patients with PWS is challenging and requires the cooperation of an experienced multidisciplinary team, including the nutritionist. An adequate clinical evaluation including nutritional and biochemical parameters should be performed to tailor the best therapeutic strategy. Both lifestyle and pharmacological interventions may represent useful strategies to prevent the high rate of morbidity and mortality related to PWS. The use of bariatric surgery is still controversial. Although it is imperative to adopt an obesity prevention strategy in childhood, there is promising evidence for the treatment of obesity in adulthood with current obesity medications in conjunction with lifestyle interventions.
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Affiliation(s)
- Luigi Barrea
- Dipartimento Di Scienze Umanistiche, Centro Direzionale, Università Telematica Pegaso, Via Porzioisola F2, 80143 Naples, Italy
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Claudia Vetrani
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Danilo Fintini
- grid.414125.70000 0001 0727 6809Endocrinology Unit, Bambino Gesù Children Hospital, Reference Center for Prader–Willi Syndrome, Rome, Italy
| | - Giulia de Alteriis
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Filippo Maria Panfili
- grid.6530.00000 0001 2300 0941School of Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Sarah Bocchini
- grid.414125.70000 0001 0727 6809Endocrinology Unit, Bambino Gesù Children Hospital, Reference Center for Prader–Willi Syndrome, Rome, Italy
| | - Ludovica Verde
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Annamaria Colao
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XCattedra Unesco “Educazione Alla Salute E Allo Sviluppo Sostenibile”, University Federico II, Naples, Italy
| | - Silvia Savastano
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
| | - Giovanna Muscogiuri
- Department of Clinical Medicine and Surgery, Endocrinology Unit, Centro Italiano Per La Cura E Il Benessere del Paziente Con Obesità (C.I.B.O), University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XDipartimento Di Medicina Clinica E Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Via Sergio Pansini 5, 80131 Naples, Italy
- grid.4691.a0000 0001 0790 385XCattedra Unesco “Educazione Alla Salute E Allo Sviluppo Sostenibile”, University Federico II, Naples, Italy
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Royan MR, Siddique K, Csucs G, Puchades MA, Nourizadeh-Lillabadi R, Bjaalie JG, Henkel CV, Weltzien FA, Fontaine R. 3D Atlas of the Pituitary Gland of the Model Fish Medaka ( Oryzias latipes). Front Endocrinol (Lausanne) 2021; 12:719843. [PMID: 34497587 PMCID: PMC8419251 DOI: 10.3389/fendo.2021.719843] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/12/2021] [Indexed: 12/23/2022] Open
Abstract
In vertebrates, the anterior pituitary plays a crucial role in regulating several essential physiological processes via the secretion of at least seven peptide hormones by different endocrine cell types. Comparative and comprehensive knowledge of the spatial distribution of those endocrine cell types is required to better understand their physiological functions. Using medaka as a model and several combinations of multi-color fluorescence in situ hybridization, we present the first 3D atlas revealing the gland-wide distribution of seven endocrine cell populations: lactotropes, thyrotropes, Lh and Fsh gonadotropes, somatotropes, and pomca-expressing cells (corticotropes and melanotropes) in the anterior pituitary of a teleost fish. By combining in situ hybridization and immunofluorescence techniques, we deciphered the location of corticotropes and melanotropes within the pomca-expressing cell population. The 3D localization approach reveals sexual dimorphism of tshba-, pomca-, and lhb-expressing cells in the adult medaka pituitary. Finally, we show the existence of bi-hormonal cells co-expressing lhb-fshb, fshb-tshba and lhb-sl using single-cell transcriptomics analysis and in situ hybridization. This study offers a solid basis for future comparative studies of the teleost pituitary and its functional plasticity.
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Affiliation(s)
- Muhammad Rahmad Royan
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Khadeeja Siddique
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Gergely Csucs
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Maja A. Puchades
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | - Jan G. Bjaalie
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Christiaan V. Henkel
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Finn-Arne Weltzien
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Romain Fontaine
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
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Sanderson MR, Fahlman RP, Wevrick R. The N-terminal domain of the Schaaf-Yang syndrome protein MAGEL2 likely has a role in RNA metabolism. J Biol Chem 2021; 297:100959. [PMID: 34265304 PMCID: PMC8350409 DOI: 10.1016/j.jbc.2021.100959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/22/2021] [Accepted: 07/11/2021] [Indexed: 02/08/2023] Open
Abstract
MAGEL2 encodes the L2 member of the melanoma-associated antigen gene (MAGE) protein family, truncating mutations of which can cause Schaaf-Yang syndrome, an autism spectrum disorder. MAGEL2 is also inactivated in Prader-Willi syndrome, which overlaps clinically and mechanistically with Schaaf-Yang syndrome. Studies to date have only investigated the C-terminal portion of the MAGEL2 protein, containing the MAGE homology domain that interacts with RING-E3 ubiquitin ligases and deubiquitinases to form protein complexes that modify protein ubiquitination. In contrast, the N-terminal portion of the MAGEL2 protein has never been studied. Here, we find that MAGEL2 has a low-complexity intrinsically disordered N-terminus rich in Pro-Xn-Gly motifs that is predicted to mediate liquid-liquid phase separation to form biomolecular condensates. We used proximity-dependent biotin identification (BioID) and liquid chromatography-tandem mass spectrometry to identify MAGEL2-proximal proteins, then clustered these proteins into functional networks. We determined that coding mutations analogous to disruptive mutations in other MAGE proteins alter these networks in biologically relevant ways. Proteins identified as proximal to the N-terminal portion of MAGEL2 are primarily involved in mRNA metabolic processes and include three mRNA N 6-methyladenosine (m6A)-binding YTHDF proteins and two RNA interference-mediating TNRC6 proteins. We found that YTHDF2 coimmunoprecipitates with MAGEL2, and coexpression of MAGEL2 reduces the nuclear accumulation of YTHDF2 after heat shock. We suggest that the N-terminal region of MAGEL2 may have a role in RNA metabolism and in particular the regulation of mRNAs modified by m6A methylation. These results provide mechanistic insight into pathogenic MAGEL2 mutations associated with Schaaf-Yang syndrome and related disorders.
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Affiliation(s)
- Matthea R Sanderson
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.
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Barton JR, Snook AE, Waldman SA. From leptin to lasers: the past and present of mouse models of obesity. Expert Opin Drug Discov 2021; 16:777-790. [PMID: 33472452 PMCID: PMC8243785 DOI: 10.1080/17460441.2021.1877654] [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: 09/11/2020] [Accepted: 01/14/2021] [Indexed: 10/22/2022]
Abstract
Introduction: Obesity is a prevalent condition that accounts for significant morbidity and mortality across the globe. Despite substantial effort, most obesity pharmacotherapies have proven unsafe or ineffective. The use of obese mouse models provides unique insight into the hormones and mechanisms that regulate appetite and metabolism. Paramount among these models are the 'obese' and 'diabetic' mice that revealed the powerful satiety hormone leptin, revolutionizing obesity research.Areas Covered: In this article, the authors discuss work on leptin therapy, and the clinical response to leptin in humans. The authors describe the use of modern mouse genetics to study targetable mechanisms for genetic forms of human obesity. Additionally, they describe mouse models of neuromodulation and their utility in unraveling neural circuits that govern appetite and metabolism.Expert opinion: Combining past and present models of obesity is required for the development of safe, effective, and impactful obesity therapy. Current research in obesity can benefit from repositories of genetically engineered mouse models to discover interactions between appetitive systems and circuits. Combining leptin therapy with other satiety signals comprising the gut-brain axis is a promising approach to induce significant enduring weight loss.
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Affiliation(s)
- Joshua R. Barton
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Adam E. Snook
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Scott A. Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Miller JL, Tan M. Dietary Management for Adolescents with Prader-Willi Syndrome. ADOLESCENT HEALTH MEDICINE AND THERAPEUTICS 2020; 11:113-118. [PMID: 32922110 PMCID: PMC7457755 DOI: 10.2147/ahmt.s214893] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/18/2020] [Indexed: 12/12/2022]
Abstract
Prader-Willi syndrome (PWS) is a complex, multisystem neurodevelopmental disorder affecting approximately 1 in 25,000 live births. PWS is caused by absence of expression of paternally inherited imprinted genes on chromosome 15q11-q13. The syndrome typically occurs due to one of three genetic mechanisms: paternal deletion of involved genes, maternal uniparental disomy, or imprinting center defects. These genetic anomalies lead to well-described clinical phenotype that includes hypotonia, hypothalamic dysfunction, social and behavioral issues, life-threatening hyperphagia, and elevated probability of obesity. Adolescents with PWS are at the highest risk for development of life-threatening obesity due to increased access to food, decreased physical activity, and hyperphagia. Currently, the only treatment for the hyperphagia is environmental control, including locked kitchens and continuous supervision of the affected individual. Caloric intake must be restricted to prevent obesity, which subsequently increases the hunger drive even more. Research and clinical practice have demonstrated that increasing physical activity along with insuring a well-balanced, nutritionally dense diet can improve overall weight control in adolescents with PWS.
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Affiliation(s)
- Jennifer L Miller
- Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
| | - Michael Tan
- Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
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Wu RN, Hung WC, Chen CT, Tsai LP, Lai WS, Min MY, Wong SB. Firing activity of locus coeruleus noradrenergic neurons decreases in necdin-deficient mice, an animal model of Prader-Willi syndrome. J Neurodev Disord 2020; 12:21. [PMID: 32727346 PMCID: PMC7389383 DOI: 10.1186/s11689-020-09323-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/17/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a neurodevelopmental disorder characterized by multiple respiratory, cognitive, endocrine, and behavioral symptoms, such as central apnea, intellectual disabilities, exaggerated stress responses, and temper tantrums. The locus coeruleus noradrenergic system (LC-NE) modulates a diverse range of behaviors, including arousal, learning, pain modulation, and stress-induced negative affective states, which are possibly correlated with the pathogenesis of PWS phenotypes. Therefore, we evaluated the LC-NE neuronal activity of necdin-deficient mice, an animal model of PWS. METHODS Heterozygous necdin-deficient mice (B6.Cg-Ndntm1ky) were bred from wild-type (WT) females to generate WT (+m/+p) and heterozygotes (+m/-p) animals, which were examined of LC-NE neuronal activity, developmental reflexes, and plethysmography. RESULTS On slice electrophysiology, LC-NE neurons of Ndntm1ky mice with necdin deficiency showed significantly decreased spontaneous activities and impaired excitability, which was mediated by enhanced A-type voltage-dependent potassium currents. Ndntm1ky mice also exhibited the neonatal phenotypes of PWS, such as hypotonia and blunt respiratory responses to hypercapnia. CONCLUSIONS LC-NE neuronal firing activity decreased in necdin-deficient mice, suggesting that LC, the primary source of norepinephrine in the central nervous system, is possibly involved in PWS pathogenesis.
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Affiliation(s)
- Rui-Ni Wu
- Department of Pediatrics, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 289, Jiangguo Rd, Xindian Dist, New Taipei City, 23142, Taiwan
| | - Wei-Chen Hung
- Department of Life Science, College of Life Science, National Taiwan University, No. 1, Sec 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Ching-Tsuey Chen
- Department of Life Science, College of Life Science, National Taiwan University, No. 1, Sec 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Li-Ping Tsai
- Department of Pediatrics, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 289, Jiangguo Rd, Xindian Dist, New Taipei City, 23142, Taiwan
- School of Medicine, Tzu Chi University, No. 701, Sec 3, Jhongyang Rd, Hualien, 97071, Taiwan
| | - Wen-Sung Lai
- Department of Psychology, National Taiwan University, No. 1, Sec 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Ming-Yuan Min
- Department of Life Science, College of Life Science, National Taiwan University, No. 1, Sec 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Shi-Bing Wong
- Department of Pediatrics, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 289, Jiangguo Rd, Xindian Dist, New Taipei City, 23142, Taiwan.
- School of Medicine, Tzu Chi University, No. 701, Sec 3, Jhongyang Rd, Hualien, 97071, Taiwan.
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Wevrick R. Disentangling ingestive behavior-related phenotypes in Prader–Willi syndrome: Integrating information from nonclinical studies and clinical trials to better understand the pathophysiology of hyperphagia and obesity. Physiol Behav 2020; 219:112864. [DOI: 10.1016/j.physbeh.2020.112864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/27/2020] [Accepted: 02/25/2020] [Indexed: 12/25/2022]
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Yu H, Chhabra KH, Thompson Z, Jones GL, Kiran S, Shangguan G, Low MJ. Hypothalamic POMC deficiency increases circulating adiponectin despite obesity. Mol Metab 2020; 35:100957. [PMID: 32244188 PMCID: PMC7082555 DOI: 10.1016/j.molmet.2020.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/22/2020] [Accepted: 01/31/2020] [Indexed: 02/06/2023] Open
Abstract
Objective The steep rise in the prevalence of obesity and its related metabolic syndrome have become a major worldwide health concerns. Melanocortin peptides from hypothalamic arcuate nucleus (Arc) POMC neurons induce satiety to limit food intake. Consequently, Arc Pomc-deficient mice (ArcPomc−/−) exhibit hyperphagia and obesity. Previous studies demonstrated that the circulating levels of adiponectin, a protein abundantly produced and secreted by fat cells, negatively correlate with obesity in both rodents and humans. However, we found that ArcPomc−/− mice have increased circulating adiponectin levels despite obesity. Therefore, we investigated the physiological function and underlying mechanisms of hypothalamic POMC in regulating systemic adiponectin levels. Methods Circulating adiponectin was measured in obese ArcPomc−/− mice at ages 4–52 weeks. To determine whether increased adiponectin was a direct result of ArcPomc deficiency or a secondary effect of obesity, we examined plasma adiponectin levels in calorie-restricted mice with or without a history of obesity and in ArcPomc−/− mice before and after genetic restoration of Pomc expression in the hypothalamus. To delineate the mechanisms causing increased adiponectin in ArcPomc−/− mice, we determined sympathetic outflow to adipose tissue by assessing epinephrine, norepinephrine, and tyrosine hydroxylase protein levels and measured the circulating adiponectin in the mice after acute norepinephrine or propranolol treatments. In addition, adiponectin mRNA and protein levels were measured in discrete adipose tissue depots to ascertain which fat depots contributed the most to the high level of adiponectin in the ArcPomc−/− mice. Finally, we generated compound Adiopoq−/−:ArcPomc−/− mice and compared their growth, body composition, and glucose homeostasis to the individual knockout mouse strains and their wild-type controls. Results Obese ArcPomc−/− female mice had unexpectedly increased plasma adiponectin compared to wild-type siblings at all ages greater than 8 weeks. Despite chronic calorie restriction to achieve normal body weights, higher adiponectin levels persisted in the ArcPomc−/− female mice. Genetic restoration of Pomc expression in the Arc or acute treatment of the ArcPomc−/− female mice with melanotan II reduced adiponectin levels to control littermate values. The ArcPomc−/− mice had defective thermogenesis and decreased epinephrine, norepinephrine, and tyrosine hydroxylase protein levels in their fat pads, indicating reduced sympathetic outflow to adipose tissue. Injections of norepinephrine into the ArcPomc−/− female mice reduced circulating adiponectin levels, whereas injections of propranolol significantly increased adiponectin levels. Despite the beneficial effects of adiponectin on metabolism, the deletion of adiponectin alleles in the ArcPomc−/− mice did not exacerbate their metabolic abnormalities. Conclusion In summary, to the best of our knowledge, this study provides the first evidence that despite obesity, the ArcPomc−/− mouse model has high circulating adiponectin levels, which demonstrated that increased fat mass is not necessarily correlated with hypoadiponectinemia. Our investigation also found a previously unknown physiological pathway connecting POMC neurons via the sympathetic nervous system to circulating adiponectin, thereby shedding light on the biological regulation of adiponectin. Obese female hypothalamic-specific Pomc-deficient mice have unexpectedly elevated circulating adiponectin. Restoration of Pomc expression in the hypothalamus reduces plasma adiponectin. Low sympathetic output to subcutaneous fat depots in the Pomc-deficient mice contributes to high adiponectin levels. Deletion of adiponectin in hypothalamic-specific Pomc-deficient mice does not alter their metabolic phenotype.
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Affiliation(s)
- Hui Yu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
| | - Kavaljit H Chhabra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Zoe Thompson
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Graham L Jones
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Sylee Kiran
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; School of Literature, Science, and Arts, University of Michigan, Ann Arbor, MI, USA
| | - Gary Shangguan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
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14
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Millership SJ, Van de Pette M, Withers DJ. Genomic imprinting and its effects on postnatal growth and adult metabolism. Cell Mol Life Sci 2019; 76:4009-4021. [PMID: 31270580 PMCID: PMC6785587 DOI: 10.1007/s00018-019-03197-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/10/2019] [Accepted: 06/17/2019] [Indexed: 12/25/2022]
Abstract
Imprinted genes display parent-of-origin-specific expression with this epigenetic system of regulation found exclusively in therian mammals. Historically, defined imprinted gene functions were almost solely focused on pregnancy and the influence on the growth parameters of the developing embryo and placenta. More recently, a number of postnatal functions have been identified which converge on resource allocation, both for animals in the nest and in adults. While many of the prenatal functions of imprinted genes that have so far been described adhere to the "parental conflict" hypothesis, no clear picture has yet emerged on the functional role of imprints on postnatal metabolism. As these roles are uncovered, interest in the potential for these genes to influence postnatal metabolism and associated adult-onset disease outcomes when dysregulated has gathered pace. Here, we review the published data on imprinted genes and their influence on postnatal metabolism, starting in the nest, and then progressing through to adulthood. When observing the functional effects of these genes on adult metabolism, we must always be careful to acknowledge the influence both of direct expression in the relevant metabolic tissue, but also indirect metabolic programming effects caused by their modulation of both in utero and postnatal growth trajectories.
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Affiliation(s)
- Steven J Millership
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
| | - Mathew Van de Pette
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Dominic J Withers
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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15
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Carias KV, Wevrick R. Preclinical Testing in Translational Animal Models of Prader-Willi Syndrome: Overview and Gap Analysis. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 13:344-358. [PMID: 30989085 PMCID: PMC6447752 DOI: 10.1016/j.omtm.2019.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder causing endocrine, musculoskeletal, and neurological dysfunction. PWS is caused by the inactivation of contiguous genes, complicating the development of targeted therapeutics. Clinical trials are now underway in PWS, with more trials to be implemented in the next few years. PWS-like endophenotypes are recapitulated in gene-targeted mice in which the function of one or more PWS genes is disrupted. These animal models can guide priorities for clinical trials or provide information about efficacy of a compound within the context of the specific disease. We now review the current status of preclinical studies that measure the effect of therapeutics on PWS-like endophenotypes. Seven categories of therapeutics (oxytocin and related compounds, K+-ATP channel agonists, melanocortin 4 receptor agonists, incretin mimetics and/or GLP-1 receptor agonists, cannabinoids, ghrelin agents, and Caralluma fimbriata [cactus] extract) have been tested for their effect on endophenotypes in both PWS animal models and clinical trials. Many other therapeutics have been tested in clinical trials, but not preclinical models of PWS or vice versa. Fostering dialogs among investigators performing preclinical validation of animal models and those implementing clinical studies will accelerate the discovery and translation of therapies into clinical practice in PWS.
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Affiliation(s)
- K Vanessa Carias
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
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16
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Oncul M, Dilsiz P, Ates Oz E, Ates T, Aklan I, Celik E, Sayar Atasoy N, Atasoy D. Impaired melanocortin pathway function in Prader-Willi syndrome gene-Magel2 deficient mice. Hum Mol Genet 2019; 27:3129-3136. [PMID: 29878108 DOI: 10.1093/hmg/ddy216] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 05/30/2018] [Indexed: 12/14/2022] Open
Abstract
Prader-Willi Syndrome (PWS) is a neurodevelopmental disorder causing social and learning deficits, impaired satiety and severe childhood obesity. Genetic underpinning of PWS involves deletion of a chromosomal region with several genes, including MAGEL2, which is abundantly expressed in the hypothalamus. Of appetite regulating hypothalamic cell types, both AGRP and POMC-expressing neurons contain Magel2 transcripts but the functional impact of its deletion on these cells has not been fully characterized. Here, we investigated these key neurons in Magel2-null mice in terms of the activity levels at different energy states as well as their behavioral function. Using cell type specific ex vivo electrophysiological recordings and in vivo chemogenetic activation approaches we evaluated impact of Magel2 deletion on AGRP and POMC-neuron induced changes in appetite. Our results suggest that POMC neuron activity profile as well as its communication with downstream targets is significantly compromised, while AGRP neuron function with respect to short term feeding is relatively unaffected in Magel2 deficiency.
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Affiliation(s)
- Merve Oncul
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Pelin Dilsiz
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Edanur Ates Oz
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Tayfun Ates
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Iltan Aklan
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Esref Celik
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Nilufer Sayar Atasoy
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Deniz Atasoy
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
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17
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Azor AM, Cole JH, Holland AJ, Dumba M, Patel MC, Sadlon A, Goldstone AP, Manning KE. Increased brain age in adults with Prader-Willi syndrome. Neuroimage Clin 2019; 21:101664. [PMID: 30658944 PMCID: PMC6412082 DOI: 10.1016/j.nicl.2019.101664] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 11/30/2018] [Accepted: 01/04/2019] [Indexed: 11/17/2022]
Abstract
Prader-Willi syndrome (PWS) is the most common genetic obesity syndrome, with associated learning difficulties, neuroendocrine deficits, and behavioural and psychiatric problems. As the life expectancy of individuals with PWS increases, there is concern that alterations in brain structure associated with the syndrome, as a direct result of absent expression of PWS genes, and its metabolic complications and hormonal deficits, might cause early onset of physiological and brain aging. In this study, a machine learning approach was used to predict brain age based on grey matter (GM) and white matter (WM) maps derived from structural neuroimaging data using T1-weighted magnetic resonance imaging (MRI) scans. Brain-predicted age difference (brain-PAD) scores, calculated as the difference between chronological age and brain-predicted age, are designed to reflect deviations from healthy brain aging, with higher brain-PAD scores indicating premature aging. Two separate adult cohorts underwent brain-predicted age calculation. The main cohort consisted of adults with PWS (n = 20; age mean 23.1 years, range 19.8-27.7; 70.0% male; body mass index (BMI) mean 30.1 kg/m2, 21.5-47.7; n = 19 paternal chromosome 15q11-13 deletion) and age- and sex-matched controls (n = 40; age 22.9 years, 19.6-29.0; 65.0% male; BMI 24.1 kg/m2, 19.2-34.2) adults (BMI PWS vs. control P = .002). Brain-PAD was significantly greater in PWS than controls (effect size mean ± SEM +7.24 ± 2.20 years [95% CI 2.83, 11.63], P = .002). Brain-PAD remained significantly greater in PWS than controls when restricting analysis to a sub-cohort matched for BMI consisting of n = 15 with PWS with BMI range 21.5-33.7 kg/m2, and n = 29 controls with BMI 21.7-34.2 kg/m2 (effect size +5.51 ± 2.56 years [95% CI 3.44, 10.38], P = .037). In the PWS group, brain-PAD scores were not associated with intelligence quotient (IQ), use of hormonal and psychotropic medications, nor severity of repetitive or disruptive behaviours. A 24.5 year old man (BMI 36.9 kg/m2) with PWS from a SNORD116 microdeletion also had increased brain PAD of 12.87 years, compared to 0.84 ± 6.52 years in a second control adult cohort (n = 95; age mean 34.0 years, range 19.9-55.5; 38.9% male; BMI 28.7 kg/m2, 19.1-43.1). This increase in brain-PAD in adults with PWS indicates abnormal brain structure that may reflect premature brain aging or abnormal brain development. The similar finding in a rare patient with a SNORD116 microdeletion implicates a potential causative role for this PWS region gene cluster in the structural brain abnormalities associated primarily with the syndrome and/or its complications. Further longitudinal neuroimaging studies are needed to clarify the natural history of this increase in brain age in PWS, its relationship with obesity, and whether similar findings are seen in those with PWS from maternal uniparental disomy.
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Affiliation(s)
- Adriana M Azor
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - James H Cole
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Anthony J Holland
- Cambridge Intellectual and Developmental Disabilities Research Group, Academic Department of Psychiatry, University of Cambridge, Cambridge, UK; National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Care Research and Care (CLAHRC), East of England, UK.
| | - Maureen Dumba
- Department of Radiology, Imperial College Healthcare NHS Trust, London, UK.
| | - Maneesh C Patel
- Department of Radiology, Imperial College Healthcare NHS Trust, London, UK.
| | - Angelique Sadlon
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Anthony P Goldstone
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK; PsychoNeuroEndocrinology Research Group, Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Katherine E Manning
- Cambridge Intellectual and Developmental Disabilities Research Group, Academic Department of Psychiatry, University of Cambridge, Cambridge, UK.
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18
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Roujeau C, Jockers R, Dam J. Endospanin 1 Determines the Balance of Leptin-Regulated Hypothalamic Functions. Neuroendocrinology 2019; 108:132-141. [PMID: 30326479 DOI: 10.1159/000494557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 10/16/2018] [Indexed: 11/19/2022]
Abstract
Endospanin 1 (Endo1), a protein encoded in humans by the same gene than the leptin receptor (ObR), and increased by diet-induced obesity, is an important regulator of ObR trafficking and cell surface exposure, determining leptin signaling strength. Defective intracellular trafficking of the leptin receptor to the neuronal plasma membrane has been proposed as a mechanism underlying the development of leptin resistance observed in human obesity. More recently, Endo1 has emerged as a mediator of "selective leptin resistance." The underlying mechanisms of the latter are not completely understood, but the possibility of differential activation of leptin signaling pathways was suggested among others. In this respect, the expression level of Endo1 is crucial for the appropriate balance between different leptin signaling pathways and leptin functions in the hypothalamus and is likely participating in selective leptin resistance for the control of energy and glucose homeostasis.
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Affiliation(s)
- Clara Roujeau
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ralf Jockers
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Julie Dam
- Inserm U1016, CNRS UMR 8104, Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, Paris,
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19
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Bischof JM, Wevrick R. Chronic diazoxide treatment decreases fat mass and improves endurance capacity in an obese mouse model of Prader-Willi syndrome. Mol Genet Metab 2018; 123:511-517. [PMID: 29506955 DOI: 10.1016/j.ymgme.2018.02.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/15/2018] [Accepted: 02/24/2018] [Indexed: 01/22/2023]
Abstract
Excess fat mass is a cardinal feature of Prader-Willi syndrome (PWS) that is recapitulated in the Magel2-null mouse model of this genetic disorder. There is a pressing need for drugs that can prevent or treat obesity in children with PWS. Recently, a clinical study of a controlled release form of the benzothiadiazine derivative diazoxide demonstrated improved metabolic parameters and decreased fat mass in obese children and adults with PWS. We tested whether chronic diazoxide administration can reduce fat mass and improve metabolism in mice lacking MAGEL2, a gene inactivated in PWS. Magel2-null and wild-type control mice were rendered obese by high fat diet feeding, then provided diazoxide while being maintained on a high fat diet. Treatment of obese mice with diazoxide reduced weight and body fat, lowered blood glucose and improved endurance capacity. Treatment with diazoxide partially normalizes obesity in children and adults with PWS and in a PWS mouse model, demonstrating that the biological pathways impacted by diazoxide may be rational pharmacological targets in PWS and other disorders diseases associated with obesity.
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Affiliation(s)
- Jocelyn M Bischof
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.
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20
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Wijesuriya TM, De Ceuninck L, Masschaele D, Sanderson MR, Carias KV, Tavernier J, Wevrick R. The Prader-Willi syndrome proteins MAGEL2 and necdin regulate leptin receptor cell surface abundance through ubiquitination pathways. Hum Mol Genet 2018; 26:4215-4230. [PMID: 28973533 DOI: 10.1093/hmg/ddx311] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/01/2017] [Indexed: 12/13/2022] Open
Abstract
In Prader-Willi syndrome (PWS), obesity is caused by the disruption of appetite-controlling pathways in the brain. Two PWS candidate genes encode MAGEL2 and necdin, related melanoma antigen proteins that assemble into ubiquitination complexes. Mice lacking Magel2 are obese and lack leptin sensitivity in hypothalamic pro-opiomelanocortin neurons, suggesting dysregulation of leptin receptor (LepR) activity. Hypothalamus from Magel2-null mice had less LepR and altered levels of ubiquitin pathway proteins that regulate LepR processing (Rnf41, Usp8, and Stam1). MAGEL2 increased the cell surface abundance of LepR and decreased their degradation. LepR interacts with necdin, which interacts with MAGEL2, which complexes with RNF41 and USP8. Mutations in the MAGE homology domain of MAGEL2 suppress RNF41 stabilization and prevent the MAGEL2-mediated increase of cell surface LepR. Thus, MAGEL2 and necdin together control LepR sorting and degradation through a dynamic ubiquitin-dependent pathway. Loss of MAGEL2 and necdin may uncouple LepR from ubiquitination pathways, providing a cellular mechanism for obesity in PWS.
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Affiliation(s)
| | - Leentje De Ceuninck
- Department of Biochemistry, VIB Center for Medical Biotechnology and Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Delphine Masschaele
- Department of Biochemistry, VIB Center for Medical Biotechnology and Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Matthea R Sanderson
- Department of Medical Genetics, University of Alberta, Edmonton T6G 2H7, Canada
| | | | - Jan Tavernier
- Department of Biochemistry, VIB Center for Medical Biotechnology and Faculty of Medicine and Health Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton T6G 2H7, Canada
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21
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Abstract
ABSTRACT
In the 1980s, mouse nuclear transplantation experiments revealed that both male and female parental genomes are required for successful development to term (McGrath and Solter, 1983; Surani and Barton, 1983). This non-equivalence of parental genomes is because imprinted genes are predominantly expressed from only one parental chromosome. Uniparental inheritance of these genomic regions causes paediatric growth disorders such as Beckwith–Wiedemann and Silver–Russell syndromes (reviewed in Peters, 2014). More than 100 imprinted genes have now been discovered and the functions of many of these genes have been assessed in murine models. The first such genes described were the fetal growth factor insulin-like growth factor 2 (Igf2) and its inhibitor Igf2 receptor (Igf2r) (DeChiara et al., 1991; Lau et al., 1994; Wang et al., 1994). Since then, it has emerged that most imprinted genes modulate fetal growth and resource acquisition in a variety of ways. First, imprinted genes are required for the development of a functional placenta, the organ that mediates the exchange of nutrients between mother and fetus. Second, these genes act in an embryo-autonomous manner to affect the growth rate and organogenesis. Finally, imprinted genes can signal the nutritional status between mother and fetus, and can modulate levels of maternal care. Importantly, many imprinted genes have been shown to affect postnatal growth and energy homeostasis. Given that abnormal birthweight correlates with adverse adult metabolic health, including obesity and cardiovascular disease, it is crucial to understand how the modulation of this dosage-sensitive, epigenetically regulated class of genes can contribute to fetal and postnatal growth, with implications for lifelong health and disease.
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Affiliation(s)
- Féaron C. Cassidy
- Queen Mary University of London, Charterhouse Square, LondonEC1M 6BQ, UK
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Alsaif M, Elliot SA, MacKenzie ML, Prado CM, Field CJ, Haqq AM. Energy Metabolism Profile in Individuals with Prader-Willi Syndrome and Implications for Clinical Management: A Systematic Review. Adv Nutr 2017; 8:905-915. [PMID: 29141973 PMCID: PMC5682993 DOI: 10.3945/an.117.016253] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a rare genetic disorder associated with excessive weight gain. Hyperphagia associated with PWS may result in higher energy intake, but alterations in energy expenditure may also contribute to energy imbalance. The purpose of this critical literature review is to determine the presence of alterations in energy expenditure in individuals with PWS. Ten studies that measured total energy expenditure (TEE), resting energy expenditure (REE), sleep energy expenditure (SEE), activity energy expenditure (AEE), and diet induced thermogenesis (DIT) were included in this review. The studies provided evidence that absolute TEE, REE, SEE, and AEE are lower in individuals with PWS than in age-, sex-, and body mass index-matched individuals without the syndrome. Alterations in lean body mass and lower physical activity amounts appear to be responsible for the lower energy expenditure in PWS rather than metabolic differences. Regardless of the underlying mechanism for lower TEE, the estimation of energy requirements with the use of equations derived for the general population would result in weight gain in individuals with PWS. The determination of energy requirements for weight management in individuals with PWS requires a more comprehensive understanding of energy metabolism. Future studies should aim to comprehensively profile all specific components of energy expenditure in individuals with PWS with the use of appropriately matched controls and gold standard methods to measure energy metabolism and body composition. One component of energy expenditure that is yet to be explored in detail in PWS is DIT. A reduced DIT (despite differences in fat free mass), secondary to hormonal dysregulation, may be present in PWS individuals, leading to a reduced overall energy expenditure. Further research exploring DIT in PWS needs to be conducted. Dietary energy recommendations for weight management in PWS have not yet been clearly established.
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Affiliation(s)
- Maha Alsaif
- Departments of Agricultural, Food and Nutritional Science, Faculty of Agriculture, Life and Environmental Sciences, Li Ka Shing Centre for Health Research Innovation, and
| | - Sarah A Elliot
- Departments of Agricultural, Food and Nutritional Science, Faculty of Agriculture, Life and Environmental Sciences, Li Ka Shing Centre for Health Research Innovation, and
| | - Michelle L MacKenzie
- Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Carla M Prado
- Departments of Agricultural, Food and Nutritional Science, Faculty of Agriculture, Life and Environmental Sciences, Li Ka Shing Centre for Health Research Innovation, and
| | - Catherine J Field
- Departments of Agricultural, Food and Nutritional Science, Faculty of Agriculture, Life and Environmental Sciences, Li Ka Shing Centre for Health Research Innovation, and
| | - Andrea M Haqq
- Departments of Agricultural, Food and Nutritional Science, Faculty of Agriculture, Life and Environmental Sciences, Li Ka Shing Centre for Health Research Innovation, and,Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Igarashi M, Narayanaswami V, Kimonis V, Galassetti PM, Oveisi F, Jung KM, Piomelli D. Dysfunctional oleoylethanolamide signaling in a mouse model of Prader-Willi syndrome. Pharmacol Res 2016; 117:75-81. [PMID: 28007570 DOI: 10.1016/j.phrs.2016.12.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/14/2016] [Accepted: 12/16/2016] [Indexed: 02/06/2023]
Abstract
Prader-Willi syndrome (PWS), the leading genetic cause of obesity, is characterized by a striking hyperphagic behavior that can lead to obesity, type-2 diabetes, cardiovascular disease and death. The molecular mechanism underlying impaired satiety in PWS is unknown. Oleoylethanolamide (OEA) is a lipid mediator involved in the control of feeding, body weight and energy metabolism. OEA produced by small-intestinal enterocytes during dietary fat digestion activates type-α peroxisome proliferator-activated receptors (PPAR-α) to trigger an afferent signal that causes satiety. Emerging evidence from genetic and human laboratory studies suggests that deficits in OEA-mediated signaling might be implicated in human obesity. In the present study, we investigated whether OEA contributes to feeding dysregulation in Magel2m+/p- (Magel2 KO) mice, an animal model of PWS. Fasted/refed male Magel2 KO mice eat more than do their wild-type littermates and become overweight with age. Meal pattern analyses show that hyperphagia in Magel2 KO is due to increased meal size and meal duration rather than to lengthening of the intermeal interval, which is suggestive of a defect in mechanisms underlying satiation. Food-dependent OEA accumulation in jejunum and fasting OEA levels in plasma are significantly greater in Magel2 KO mice than in wild-type controls. Together, these findings indicate that deletion of the Magel2 gene is accompanied by marked changes in OEA signaling. Importantly, intraperitoneal administration of OEA (10mg/kg) significantly reduces food intake in fasted/refed Magel2 KO mice, pointing to a possible use of this natural compound to control hunger in PWS.
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Affiliation(s)
- Miki Igarashi
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Vidya Narayanaswami
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Virginia Kimonis
- Department of Pediatrics, University of California, Irvine, CA, 92697, USA
| | | | - Fariba Oveisi
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Kwang-Mook Jung
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Daniele Piomelli
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, 92697, USA; Department of Biological Chemistry, University of California, Irvine, CA, 92697, USA; Department of Pharmacology, University of California, Irvine, CA, 92697, USA.
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24
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Knani I, Earley BJ, Udi S, Nemirovski A, Hadar R, Gammal A, Cinar R, Hirsch HJ, Pollak Y, Gross I, Eldar-Geva T, Reyes-Capo DP, Han JC, Haqq AM, Gross-Tsur V, Wevrick R, Tam J. Targeting the endocannabinoid/CB1 receptor system for treating obesity in Prader-Willi syndrome. Mol Metab 2016; 5:1187-1199. [PMID: 27900261 PMCID: PMC5123200 DOI: 10.1016/j.molmet.2016.10.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 02/09/2023] Open
Abstract
Objective Extreme obesity is a core phenotypic feature of Prader–Willi syndrome (PWS). Among numerous metabolic regulators, the endocannabinoid (eCB) system is critically involved in controlling feeding, body weight, and energy metabolism, and a globally acting cannabinoid-1 receptor (CB1R) blockade reverses obesity both in animals and humans. The first-in-class CB1R antagonist rimonabant proved effective in inducing weight loss in adults with PWS. However, it is no longer available for clinical use because of its centrally mediated, neuropsychiatric, adverse effects. Methods We studied eCB ‘tone’ in individuals with PWS and in the Magel2-null mouse model that recapitulates the major metabolic phenotypes of PWS and determined the efficacy of a peripherally restricted CB1R antagonist, JD5037 in treating obesity in these mice. Results Individuals with PWS had elevated circulating levels of 2-arachidonoylglycerol and its endogenous precursor and breakdown ligand, arachidonic acid. Increased hypothalamic eCB ‘tone’, manifested by increased eCBs and upregulated CB1R, was associated with increased fat mass, reduced energy expenditure, and decreased voluntary activity in Magel2-null mice. Daily chronic treatment of obese Magel2-null mice and their littermate wild-type controls with JD5037 (3 mg/kg/d for 28 days) reduced body weight, reversed hyperphagia, and improved metabolic parameters related to their obese phenotype. Conclusions Dysregulation of the eCB/CB1R system may contribute to hyperphagia and obesity in Magel2-null mice and in individuals with PWS. Our results demonstrate that treatment with peripherally restricted CB1R antagonists may be an effective strategy for the management of severe obesity in PWS. Circulating levels of endocannabinoids are increased in individuals with PWS. Magel2 is a negative regulator of hypothalamic endocannabinoid ‘tone’. Peripherally-restricted CB1 receptor blockade reverses obesity in Magel2-null mice.
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Affiliation(s)
- Ibrahim Knani
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian J Earley
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Shiran Udi
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Asaad Gammal
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Harry J Hirsch
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Yehuda Pollak
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Itai Gross
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Talia Eldar-Geva
- Reproductive Endocrinology and Genetics Unit, Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Daniela P Reyes-Capo
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Joan C Han
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA; Department of Pediatrics, University of Tennessee Health Science Center, Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, TN, USA; Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Andrea M Haqq
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Varda Gross-Tsur
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB Canada
| | - Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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25
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Kamaludin AA, Smolarchuk C, Bischof JM, Eggert R, Greer JJ, Ren J, Lee JJ, Yokota T, Berry FB, Wevrick R. Muscle dysfunction caused by loss of Magel2 in a mouse model of Prader-Willi and Schaaf-Yang syndromes. Hum Mol Genet 2016; 25:3798-3809. [PMID: 27436578 DOI: 10.1093/hmg/ddw225] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/31/2016] [Accepted: 07/07/2016] [Indexed: 01/04/2023] Open
Abstract
Prader-Willi syndrome is characterized by severe hypotonia in infancy, with decreased lean mass and increased fat mass in childhood followed by severe hyperphagia and consequent obesity. Scoliosis and other orthopaedic manifestations of hypotonia are common in children with Prader-Willi syndrome and cause significant morbidity. The relationships among hypotonia, reduced muscle mass and scoliosis have been difficult to establish. Inactivating mutations in one Prader-Willi syndrome candidate gene, MAGEL2, cause a Prader-Willi-like syndrome called Schaaf-Yang syndrome, highlighting the importance of loss of MAGEL2 in Prader-Willi syndrome phenotypes. Gene-targeted mice lacking Magel2 have excess fat and decreased muscle, recapitulating altered body composition in Prader-Willi syndrome. We now demonstrate that Magel2 is expressed in the developing musculoskeletal system, and that loss of Magel2 causes muscle-related phenotypes in mice consistent with atrophy caused by altered autophagy. Magel2-null mice serve as a preclinical model for therapies targeting muscle structure and function in children lacking MAGEL2 diagnosed with Prader-Willi or Schaaf-Yang syndrome.
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Affiliation(s)
| | | | | | | | - John J Greer
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | - Jun Ren
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | | | | | - Fred B Berry
- Department of Medical Genetics
- Department of Surgery and
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26
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Bischof JM, Van Der Ploeg LHT, Colmers WF, Wevrick R. Magel2-null mice are hyper-responsive to setmelanotide, a melanocortin 4 receptor agonist. Br J Pharmacol 2016; 173:2614-21. [PMID: 27339818 DOI: 10.1111/bph.13540] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/14/2016] [Accepted: 06/17/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE α- and β-melanocyte-stimulating hormones (MSH) are derived from pro-opiomelanocortin (POMC) and are the natural agonist ligands of the melanocortin 4 receptor, a key regulator of energy homeostasis. Recent rodent and human data have implicated the MAGEL2 gene, which may regulate activation of POMC neurons, as a significant contributor to the metabolic symptoms observed in Prader-Willi Syndrome (PWS). Firstly, patients with protein truncating mutations in MAGEL2 exhibit numerous clinical characteristics of PWS. Secondly, Magel2-null mice may not normally activate MC4 receptors, as they are defective in the activation of their POMC neurons and hence may fail to normally release the POMC-derived MC4 receptor agonist ligands α- and β-MSH. Magel2-null mice represent a tractable animal model for the metabolic and appetitive imbalance seen in patients with PWS. EXPERIMENTAL APPROACH We tested a dose titration of the MC4 receptor agonist setmelanotide, in development for rare monogenic forms of obesity, in Magel2-null mice. KEY RESULTS We show that Magel2-null mice are hypersensitive to the appetite suppressing and metabolic effects of setmelanotide. CONCLUSION AND IMPLICATIONS Setmelanotide may be a useful investigational hormone/neuropeptide replacement therapy for PWS and rare monogenic forms of obesity exhibiting impaired function of POMC neurons.
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Affiliation(s)
- Jocelyn M Bischof
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | | | - William F Colmers
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
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27
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Maillard J, Park S, Croizier S, Vanacker C, Cook JH, Prevot V, Tauber M, Bouret SG. Loss of Magel2 impairs the development of hypothalamic Anorexigenic circuits. Hum Mol Genet 2016; 25:3208-3215. [PMID: 27288456 DOI: 10.1093/hmg/ddw169] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 04/26/2016] [Accepted: 05/23/2016] [Indexed: 02/06/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a genetic disorder characterized by a variety of physiological and behavioral dysregulations, including hyperphagia, a condition that can lead to life-threatening obesity. Feeding behavior is a highly complex process with multiple feedback loops that involve both peripheral and central systems. The arcuate nucleus of the hypothalamus (ARH) is critical for the regulation of homeostatic processes including feeding, and this nucleus develops during neonatal life under of the influence of both environmental and genetic factors. Although much attention has focused on the metabolic and behavioral outcomes of PWS, an understanding of its effects on the development of hypothalamic circuits remains elusive. Here, we show that mice lacking Magel2, one of the genes responsible for the etiology of PWS, display an abnormal development of ARH axonal projections. Notably, the density of anorexigenic α-melanocyte-stimulating hormone axons was reduced in adult Magel2-null mice, while the density of orexigenic agouti-related peptide fibers in the mutant mice appeared identical to that in control mice. On the basis of previous findings showing a pivotal role for metabolic hormones in hypothalamic development, we also measured leptin and ghrelin levels in Magel2-null and control neonates and found that mutant mice have normal leptin and ghrelin levels. In vitro experiments show that Magel2 directly promotes axon growth. Together, these findings suggest that a loss of Magel2 leads to the disruption of hypothalamic feeding circuits, an effect that appears to be independent of the neurodevelopmental effects of leptin and ghrelin and likely involves a direct neurotrophic effect of Magel2.
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Affiliation(s)
- Julien Maillard
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Department of Pediatrics, Los Angeles, CA 90027, USA.,Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille 59045, France
| | - Soyoung Park
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Department of Pediatrics, Los Angeles, CA 90027, USA
| | - Sophie Croizier
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Department of Pediatrics, Los Angeles, CA 90027, USA
| | - Charlotte Vanacker
- Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille 59045, France
| | - Joshua H Cook
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Department of Pediatrics, Los Angeles, CA 90027, USA
| | - Vincent Prevot
- Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille 59045, France
| | | | - Sebastien G Bouret
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Department of Pediatrics, Los Angeles, CA 90027, USA .,Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille 59045, France
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28
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Perez JD, Rubinstein ND, Dulac C. New Perspectives on Genomic Imprinting, an Essential and Multifaceted Mode of Epigenetic Control in the Developing and Adult Brain. Annu Rev Neurosci 2016; 39:347-84. [PMID: 27145912 DOI: 10.1146/annurev-neuro-061010-113708] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mammalian evolution entailed multiple innovations in gene regulation, including the emergence of genomic imprinting, an epigenetic regulation leading to the preferential expression of a gene from its maternal or paternal allele. Genomic imprinting is highly prevalent in the brain, yet, until recently, its central roles in neural processes have not been fully appreciated. Here, we provide a comprehensive survey of adult and developmental brain functions influenced by imprinted genes, from neural development and wiring to synaptic function and plasticity, energy balance, social behaviors, emotions, and cognition. We further review the widespread identification of parental biases alongside monoallelic expression in brain tissues, discuss their potential roles in dosage regulation of key neural pathways, and suggest possible mechanisms underlying the dynamic regulation of imprinting in the brain. This review should help provide a better understanding of the significance of genomic imprinting in the normal and pathological brain of mammals including humans.
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Affiliation(s)
- Julio D Perez
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Nimrod D Rubinstein
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Catherine Dulac
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
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29
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Luchtman DW, Chee MJS, Doslikova B, Marks DL, Baracos VE, Colmers WF. Defense of Elevated Body Weight Setpoint in Diet-Induced Obese Rats on Low Energy Diet Is Mediated by Loss of Melanocortin Sensitivity in the Paraventricular Hypothalamic Nucleus. PLoS One 2015; 10:e0139462. [PMID: 26444289 PMCID: PMC4596859 DOI: 10.1371/journal.pone.0139462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 09/12/2015] [Indexed: 01/15/2023] Open
Abstract
Some animals and humans fed a high-energy diet (HED) are diet-resistant (DR), remaining as lean as individuals who were naïve to HED. Other individuals become obese during HED exposure and subsequently defend the obese weight (Diet-Induced Obesity- Defenders, DIO-D) even when subsequently maintained on a low-energy diet. We hypothesized that the body weight setpoint of the DIO-D phenotype resides in the hypothalamic paraventricular nucleus (PVN), where anorexigenic melanocortins, including melanotan II (MTII), increase presynaptic GABA release, and the orexigenic neuropeptide Y (NPY) inhibits it. After prolonged return to low-energy diet, GABA inputs to PVN neurons from DIO-D rats exhibited highly attenuated responses to MTII compared with those from DR and HED-naïve rats. In DIO-D rats, melanocortin-4 receptor expression was significantly reduced in dorsomedial hypothalamus, a major source of GABA input to PVN. Unlike melanocortin responses, NPY actions in PVN of DIO-D rats were unchanged, but were reduced in neurons of the ventromedial hypothalamic nucleus; in PVN of DR rats, NPY responses were paradoxically increased. MTII-sensitivity was restored in DIO-D rats by several weeks’ refeeding with HED. The loss of melanocortin sensitivity restricted to PVN of DIO-D animals, and its restoration upon prolonged refeeding with HED suggest that their melanocortin systems retain the ability to up- and downregulate around their elevated body weight setpoint in response to longer-term changes in dietary energy density. These properties are consistent with a mechanism of body weight setpoint.
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Affiliation(s)
- Dirk W. Luchtman
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Melissa J. S. Chee
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Barbora Doslikova
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel L. Marks
- Papé Family Pediatric Research Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd. Portland, Oregon, United States of America
| | - Vickie E. Baracos
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - William F. Colmers
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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