1
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Reznik DL, Yang MV, Albelda de la Haza P, Jain A, Spanjaard M, Theiss S, Schaaf CP, Malovannaya A, Strong TV, Veeraragavan S, Samaco RC. Magel2 truncation alters select behavioral and physiological outcomes in a rat model of Schaaf-Yang syndrome. Dis Model Mech 2023; 16:286598. [PMID: 36637363 PMCID: PMC9922728 DOI: 10.1242/dmm.049829] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/04/2023] [Indexed: 01/14/2023] Open
Abstract
Previous studies in mice have utilized Magel2 gene deletion models to examine the consequences of its absence. We report the generation, molecular validation and phenotypic characterization of a novel rat model with a truncating Magel2 mutation modeling variants associated with Schaaf-Yang syndrome-causing mutations. Within the hypothalamus, a brain region in which human MAGEL2 is paternally expressed, we demonstrated, at the level of transcript and peptide detection, that rat Magel2 exhibits a paternal, parent-of-origin effect. In evaluations of behavioral features across several domains, juvenile Magel2 mutant rats displayed alterations in anxiety-like behavior and sociability measures. Moreover, the analysis of peripheral organ systems detected alterations in body composition, cardiac structure and function, and breathing irregularities in Magel2 mutant rats. Several of these findings are concordant with reported mouse phenotypes, indicating the conservation of MAGEL2 function across rodent species. Our comprehensive analysis revealing impairments across multiple domains demonstrates the tractability of this model system for the study of truncating MAGEL2 mutations.
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Affiliation(s)
- Derek L Reznik
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.,Texas Children's Hospital, Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Mingxiao V Yang
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.,Texas Children's Hospital, Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Pedro Albelda de la Haza
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.,Texas Children's Hospital, Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Antrix Jain
- Baylor College of Medicine, Mass Spectrometry Proteomics Core, Houston, TX 77030, USA
| | - Melanie Spanjaard
- Heidelberg University, Institute of Human Genetics, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Susanne Theiss
- Heidelberg University, Institute of Human Genetics, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christian P Schaaf
- Heidelberg University, Institute of Human Genetics, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Anna Malovannaya
- Baylor College of Medicine, Mass Spectrometry Proteomics Core, Houston, TX 77030, USA.,Baylor College of Medicine, Verna and Marrs McLean Departments of Biochemistry and Molecular Biology, and Molecular and Cellular Biology, Houston, TX 77030, USA.,Baylor College of Medicine, Dan L. Duncan Comprehensive Cancer Center, Houston, TX 77030, USA
| | - Theresa V Strong
- Foundation for Prader-Willi Research, Walnut, CA 91789, USA.,Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Surabi Veeraragavan
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.,Texas Children's Hospital, Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Rodney C Samaco
- Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.,Texas Children's Hospital, Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
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2
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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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3
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Guyot E, Dougkas A, Nazare JA, Bagot S, Disse E, Iceta S. A systematic review and meta-analyses of food preference modifications after bariatric surgery. Obes Rev 2021; 22:e13315. [PMID: 34312976 DOI: 10.1111/obr.13315] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022]
Abstract
This systematic review and meta-analyses aimed to synthesize evidence of the link between bariatric surgery and changes in food preferences, considering the method of assessment. MEDLINE, Cochrane Library, Web of Science, Cinahl, PsychINFO, ProQuest, and Open grey were searched incorporating two blocks of terms ("Intervention" and "Food Preferences"). Interventional or observational studies involving patients (BMI ≥ 35 kg m-2 ) with sleeve gastrectomy (SG) or Roux-en-Y Gastric Bypass (RYGB) and a control group were included. Meta-analyses were performed comparing the standardized daily mean percentage energy from proteins, carbohydrates, and lipids between preoperative and postoperative patients. Fifty-seven studies concerning 2,271 patients with RYGB and 903 patients with SG met the inclusion criteria, of which 24 were eligible for meta-analysis. Despite a total reduction in macronutrient intakes, the meta-analyses revealed a postoperative increase in percentage energy from proteins at 12 months (0.24, 95% CI: 0.03, 0.46, {I2 } = 73%) and a decrease in percentage energy from fat at 1 month (-0.47, 95% CI: 0.86, 0.09, {I2 } = 72%), up to 24 months (-0.20, 95% CI: -0.31, 0.08, {I2 } = 0%). In conclusion, the present systematic review and meta-analyses showed changes of food preferences in terms of macronutrient, food selection and, overall food appreciation up to 5 years following bariatric surgery.
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Affiliation(s)
- Erika Guyot
- Centre Européen Nutrition et Santé (CENS), Centre de Recherche en Nutrition Humaine Rhône-Alpes (CRNH-RA), Pierre-Bénite, France.,Institut Paul Bocuse Research Center, Ecully, France
| | | | - Julie-Anne Nazare
- Centre Européen Nutrition et Santé (CENS), Centre de Recherche en Nutrition Humaine Rhône-Alpes (CRNH-RA), Pierre-Bénite, France.,Laboratoire CarMeN, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Sarah Bagot
- Centre Européen Nutrition et Santé (CENS), Centre de Recherche en Nutrition Humaine Rhône-Alpes (CRNH-RA), Pierre-Bénite, France.,Institut Paul Bocuse Research Center, Ecully, France
| | - Emmanuel Disse
- Centre Européen Nutrition et Santé (CENS), Centre de Recherche en Nutrition Humaine Rhône-Alpes (CRNH-RA), Pierre-Bénite, France.,Laboratoire CarMeN, Université Claude Bernard Lyon 1, Pierre-Bénite, France.,Department of Endocrinology, Diabetes and Nutrition, Integrated Center for Obesity, Hospices Civils de Lyon, Lyon-Sud Hospital, Pierre-Bénite, France
| | - Sylvain Iceta
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec-Université Laval, Quebec, Quebec, Canada
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4
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Kummerfeld DM, Raabe CA, Brosius J, Mo D, Skryabin BV, Rozhdestvensky TS. A Comprehensive Review of Genetically Engineered Mouse Models for Prader-Willi Syndrome Research. Int J Mol Sci 2021; 22:3613. [PMID: 33807162 PMCID: PMC8037846 DOI: 10.3390/ijms22073613] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 02/05/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a neurogenetic multifactorial disorder caused by the deletion or inactivation of paternally imprinted genes on human chromosome 15q11-q13. The affected homologous locus is on mouse chromosome 7C. The positional conservation and organization of genes including the imprinting pattern between mice and men implies similar physiological functions of this locus. Therefore, considerable efforts to recreate the pathogenesis of PWS have been accomplished in mouse models. We provide a summary of different mouse models that were generated for the analysis of PWS and discuss their impact on our current understanding of corresponding genes, their putative functions and the pathogenesis of PWS. Murine models of PWS unveiled the contribution of each affected gene to this multi-facetted disease, and also enabled the establishment of the minimal critical genomic region (PWScr) responsible for core symptoms, highlighting the importance of non-protein coding genes in the PWS locus. Although the underlying disease-causing mechanisms of PWS remain widely unresolved and existing mouse models do not fully capture the entire spectrum of the human PWS disorder, continuous improvements of genetically engineered mouse models have proven to be very powerful and valuable tools in PWS research.
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Affiliation(s)
- Delf-Magnus Kummerfeld
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Carsten A. Raabe
- Research Group Regulatory Mechanisms of Inflammation, Institute of Medical Biochemistry (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Juergen Brosius
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
- Institutes for Systems Genetics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Dingding Mo
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China;
| | - Boris V. Skryabin
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
| | - Timofey S. Rozhdestvensky
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), University of Muenster, Von-Esmarch-Str. 56, D-48149 Muenster, Germany;
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5
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Abstract
Reviewed here are multiple mouse models of vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) that have emerged over the past decade. These models use diverse approaches to both operative and perioperative procedures. Scrutinizing the benefits and pitfalls of each surgical model and what to expect in terms of post-operative outcomes will enhance our assessment of studies using mouse models, as well as advance our understanding of their translational potential. Two mouse models of bariatric surgery, VSG-lembert and RYGB-small pouch, demonstrate low mortality and most closely recapitulate the human forms of surgery. The use of liquid diets can be minimized, and in mice, RYGB demonstrates more reliable and longer lasting effects on weight loss compared to that of VSG.
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6
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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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Douros JD, Tong J, D’Alessio DA. The Effects of Bariatric Surgery on Islet Function, Insulin Secretion, and Glucose Control. Endocr Rev 2019; 40:1394-1423. [PMID: 31241742 PMCID: PMC6749890 DOI: 10.1210/er.2018-00183] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 04/23/2019] [Indexed: 01/19/2023]
Abstract
Although bariatric surgery was developed primarily to treat morbid obesity, evidence from the earliest clinical observations to the most recent clinical trials consistently demonstrates that these procedures have substantial effects on glucose metabolism. A large base of research indicates that bariatric surgeries such as Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and biliopancreatic diversion (BPD) improve diabetes in most patients, with effects frequently evident prior to substantial weight reduction. There is now unequivocal evidence from randomized controlled trials that the efficacy of surgery is superior to intensive life-style/medical management. Despite advances in the clinical understanding and application of bariatric surgery, there remains only limited knowledge of the mechanisms by which these procedures confer such large changes to metabolic physiology. The improvement of insulin sensitivity that occurs with weight loss (e.g., the result of diet, illness, physical training) also accompanies bariatric surgery. However, there is evidence to support specific effects of surgery on insulin clearance, hepatic glucose production, and islet function. Understanding the mechanisms by which surgery affects these parameters of glucose regulation has the potential to identify new targets for therapeutic discovery. Studies to distinguish among bariatric surgeries on key parameters of glucose metabolism are limited but would be of considerable value to assist clinicians in selecting specific procedures and investigators in delineating the resulting physiology. This review is based on literature related to factors governing glucose metabolism and insulin secretion after the commonly used RYGB and VSG, and the less frequently used BPD and adjustable gastric banding.
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Affiliation(s)
- Jonathan D Douros
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
| | - Jenny Tong
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
| | - David A D’Alessio
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
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8
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Douros JD, Niu J, Sdao S, Gregg T, Fisher-Wellman K, Bharadwaj M, Molina A, Arumugam R, Martin M, Petretto E, Merrins MJ, Herman MA, Tong J, Campbell J, D’Alessio D. Sleeve gastrectomy rapidly enhances islet function independently of body weight. JCI Insight 2019; 4:126688. [PMID: 30777938 PMCID: PMC6483064 DOI: 10.1172/jci.insight.126688] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/11/2019] [Indexed: 12/14/2022] Open
Abstract
Bariatric surgeries including vertical sleeve gastrectomy (VSG) ameliorate obesity and diabetes. Weight loss and accompanying increases to insulin sensitivity contribute to improved glycemia after surgery; however, studies in humans also suggest weight-independent actions of bariatric procedures to lower blood glucose, possibly by improving insulin secretion. To evaluate this hypothesis, we compared VSG-operated mice with pair-fed, sham-surgical controls (PF-Sham) 2 weeks after surgery. This paradigm yielded similar postoperative body weight and insulin sensitivity between VSG and calorically restricted PF-Sham animals. However, VSG improved glucose tolerance and markedly enhanced insulin secretion during oral nutrient and i.p. glucose challenges compared with controls. Islets from VSG mice displayed a unique transcriptional signature enriched for genes involved in Ca2+ signaling and insulin secretion pathways. This finding suggests that bariatric surgery leads to intrinsic changes within the islet that alter function. Indeed, islets isolated from VSG mice had increased glucose-stimulated insulin secretion and a left-shifted glucose sensitivity curve compared with islets from PF-Sham mice. Isolated islets from VSG animals showed corresponding increases in the pulse duration of glucose-stimulated Ca2+ oscillations. Together, these findings demonstrate a weight-independent improvement in glycemic control following VSG, which is, in part, driven by improved insulin secretion and associated with substantial changes in islet gene expression. These results support a model in which β cells play a key role in the adaptation to bariatric surgery and the improved glucose tolerance that is typical of these procedures.
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Affiliation(s)
- Jonathan D. Douros
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Jingjing Niu
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Sophia Sdao
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Trillian Gregg
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kelsey Fisher-Wellman
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Manish Bharadwaj
- Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Anthony Molina
- Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Ramamani Arumugam
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - MacKenzie Martin
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Enrico Petretto
- Centre for Computational Biology, Duke-NUS Medical School, Singapore
| | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mark A. Herman
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Jenny Tong
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - Jonathan Campbell
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
| | - David D’Alessio
- Division of Endocrinology, Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA
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9
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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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10
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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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11
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Hankir MK, Seyfried F, Miras AD, Cowley MA. Brain Feeding Circuits after Roux-en-Y Gastric Bypass. Trends Endocrinol Metab 2018; 29:218-237. [PMID: 29475578 DOI: 10.1016/j.tem.2018.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/17/2018] [Accepted: 01/25/2018] [Indexed: 12/12/2022]
Abstract
Metabolic surgical procedures, such as Roux-en-Y gastric bypass (RYGB), uniquely reprogram feeding behavior and body weight in obese subjects. Clinical neuroimaging and animal studies are only now beginning to shed light on some of the underlying central mechanisms. We present here the roles of key brain neurotransmitter/neuromodulator systems in food choice, value, and intake at various stages after RYGB. In doing so, we elaborate on how known signals emanating from the reorganized gut, including peptide hormones and microbiota products, impinge on newly mapped homeostatic and hedonic brain feeding circuits. Continued progress in the rapidly evolving field of metabolic surgery will inform the design of more effective weight-loss compounds.
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Affiliation(s)
- Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany; German Research Foundation Collaborative Research Center in Obesity Mechanisms, University of Leipzig, Leipzig, Saxony 04103, Germany.
| | - Florian Seyfried
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria 97080, Germany
| | - Alexander D Miras
- Department of Investigative Science, Imperial College London Academic Healthcare Centre, London W12 0NN, UK
| | - Michael A Cowley
- Metabolic Disease and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia; Department of Physiology, Monash University, Victoria 3800, Australia
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12
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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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Zakeri R, Batterham RL. Potential mechanisms underlying the effect of bariatric surgery on eating behaviour. Curr Opin Endocrinol Diabetes Obes 2018; 25:3-11. [PMID: 29120924 DOI: 10.1097/med.0000000000000379] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Reduced energy intake, resulting from favourable changes in eating behaviour, is the predominant driver of weight loss following bariatric surgery. Here we review the most recent studies examining the impact of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy, the two most common bariatric procedures, upon eating behaviour and the suggested underlying biological mechanisms. RECENT FINDINGS Following RYGB or sleeve gastrectomy, most people report subjective changes in appetite, taste and food preference, with decreased high-fat preference most commonly reported. Objective postsurgery changes in taste and olfactory acuity occur. A new phenomenon, 'meal-size aversion', may contribute to reduced postoperative energy intake. Recent studies provide evidence for peptide YY3-36, glucagon-like peptide-1, ghrelin, neurotensin and oleoylethanolamide as mediators of postoperative eating behaviour changes. Factors modulating these changes include sex, type 2 diabetes status, genetics and bariatric procedure. New studies implicate central dopaminergic and opioid receptor signalling as key neural mediators driving altered eating behaviour. Brain neuroimaging studies show that obesity-associated changes in food-cue responses, brain connectivity and structural abnormalities are normalized following bariatric surgery. SUMMARY Understanding the biological mechanisms mediating the eating behaviour changes engendered by bariatric surgery may lead to the development of novel therapeutic strategies for people with obesity.
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Affiliation(s)
- Roxanna Zakeri
- Centre for Obesity Research, Rayne Institute, Department of Medicine, University College London, London, UK
- University College London Hospital (UCLH) Bariatric Centre for Weight Management and Metabolic Surgery, University College London Hospital, London, UK
- National Institute of Health Research, UCLH Biomedical Research Centre, London, UK
| | - Rachel L Batterham
- Centre for Obesity Research, Rayne Institute, Department of Medicine, University College London, London, UK
- University College London Hospital (UCLH) Bariatric Centre for Weight Management and Metabolic Surgery, University College London Hospital, London, UK
- National Institute of Health Research, UCLH Biomedical Research Centre, London, UK
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Celiker H. A new proposed mechanism of action for gastric bypass surgery: Air hypothesis. Med Hypotheses 2017; 107:81-89. [PMID: 28915970 DOI: 10.1016/j.mehy.2017.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/02/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023]
Abstract
Roux-en-Y gastric bypass (RYGB) surgery is one of the most effective treatments for obesity and type II diabetes. RYGB was originally believed to work by mechanically restricting caloric intake or causing macronutrient malabsorption. However, such mechanical effects play no role in the remarkable efficacy of gastric bypass. Instead, mounting evidence shows that altered neuroendocrine signaling is responsible for the weight reducing effects of RYGB. The exact mechanism of this surgical response is still a mystery. Here, we propose that RYGB leads to weight loss primarily by inducing a functional shift in the gut microbiome, manifested by a relative expansion of aerobic bacteria numbers in the colon. We point to compelling evidence that gastric bypass changes the function of the microbiome by disrupting intestinal gas homeostasis, causing excessive transit of swallowed air (oxygen) into the colon.
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Affiliation(s)
- Hasan Celiker
- Xeno Biosciences Inc., 12 Mt Auburn St #7, Cambridge, MA, USA.
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