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Jayarathne HSM, Sullivan R, Stilgenbauer L, Debarba LK, Kuchumov A, Koshko L, Scofield S, Liu W, Ginsburg BC, Miller RA, Sadagurski M. Hypothalamic sex-specific metabolic shift by canagliflozin during aging. GeroScience 2024; 46:4479-4493. [PMID: 38801647 PMCID: PMC11335982 DOI: 10.1007/s11357-024-01214-z] [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: 03/26/2024] [Accepted: 05/18/2024] [Indexed: 05/29/2024] Open
Abstract
The hypothalamus undergoes significant changes with aging and plays crucial roles in age-related metabolic alterations. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are anti-diabetic agents that promote glucose excretion, and metabolic homeostasis. Recent studies have shown that a SGLT2i, Canagliflozin (Cana), can extend the median survival of genetically heterogeneous UM-HET3 male mice and improve central metabolic control via increases in hypothalamic insulin responsiveness in aged males, as well as reduced age-associated hypothalamic inflammation. We studied the long- and short-term effects of Cana on hypothalamic metabolic control in UM-HET3 mice. Starting the treatment from 7 months of age, we show that 4 weeks of Cana treatment significantly reduced body weight and fat mass in male but not female mice that was associated with enhanced glucose tolerance and insulin sensitivity observed by 12 months. Indirect calorimetry showed that Cana treatment increased energy expenditure in male, but not female mice, at 12 months of age. Long-term Cana treatment increased metabolic rates in both sexes, and markedly increasing formation of both orexigenic and anorexigenic projections to the paraventricular nucleus of the hypothalamus (PVH) mostly in females by 25 months. Hypothalamic RNA-sequencing analysis revealed increased sex-specific genes and signaling pathways related to insulin signaling, glycogen catabolic pathway, neuropeptide signaling, and mitochondrial function upregulated by Cana, with males showing a more pronounced and sustained effect on metabolic pathways at both age groups. Overall, our data provide critical evidence for sex-specific mechanisms that are affected by Cana during aging suggesting key targets of hypothalamic Cana-induced neuroprotection for metabolic control.
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Affiliation(s)
- Hashan S M Jayarathne
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Ryan Sullivan
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Lukas Stilgenbauer
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Lucas K Debarba
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Artur Kuchumov
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Lisa Koshko
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Sydney Scofield
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA
| | - Wanqing Liu
- Department of Pharmaceutical Science, Wayne State University, Detroit, MI, USA
| | - Brett C Ginsburg
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, San Antonio, TX, USA
| | - Richard A Miller
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Marianna Sadagurski
- Department of Biological Sciences, Integrative Biosciences Center, Wayne State University, Room 2418 IBio, 6135 Woodward, Detroit, MI, 48202, USA.
- Institute of Environmental Health Sciences, iBio (Integrative Biosciences Center), Wayne State University, Detroit, MI, USA.
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2
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Fico BG, Maharaj A, Pena GS, Huang CJ. The Effects of Obesity on the Inflammatory, Cardiovascular, and Neurobiological Responses to Exercise in Older Adults. BIOLOGY 2023; 12:865. [PMID: 37372149 DOI: 10.3390/biology12060865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/30/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
Obesity with advancing age leads to increased health complications that are involved in various complex physiological processes. For example, inflammation is a critical cardiovascular disease risk factor that plays a role in the stages of atherosclerosis in both aging and obesity. Obesity can also induce profound changes to the neural circuitry that regulates food intake and energy homeostasis with advancing age. Here we discuss how obesity in older adults impacts inflammatory, cardiovascular, and neurobiological functions with an emphasis on how exercise mediates each topic. Although obesity is a reversible disorder through lifestyle changes, it is important to note that early interventions are crucial to prevent pathological changes seen in the aging obese population. Lifestyle modifications such as physical activity (including aerobic and resistance training) should be considered as a main intervention to minimize the synergistic effect of obesity on age-related conditions, such as cerebrovascular disease.
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Affiliation(s)
- Brandon G Fico
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Arun Maharaj
- Department of Epidemiology and Cancer Control, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Gabriel S Pena
- Department of Kinesiology, University of Maryland, College Park, MD 20742, USA
| | - Chun-Jung Huang
- Exercise Biochemistry Laboratory, Department of Exercise Science and Health Promotion, Florida Atlantic University, Boca Raton, FL 33431, USA
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3
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Liu T, Xu Y, Yi CX, Tong Q, Cai D. The hypothalamus for whole-body physiology: from metabolism to aging. Protein Cell 2022; 13:394-421. [PMID: 33826123 PMCID: PMC9095790 DOI: 10.1007/s13238-021-00834-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/01/2021] [Indexed: 01/05/2023] Open
Abstract
Obesity and aging are two important epidemic factors for metabolic syndrome and many other health issues, which contribute to devastating diseases such as cardiovascular diseases, stroke and cancers. The brain plays a central role in controlling metabolic physiology in that it integrates information from other metabolic organs, sends regulatory projections and orchestrates the whole-body function. Emerging studies suggest that brain dysfunction in sensing various internal cues or processing external cues may have profound effects on metabolic and other physiological functions. This review highlights brain dysfunction linked to genetic mutations, sex, brain inflammation, microbiota, stress as causes for whole-body pathophysiology, arguing brain dysfunction as a root cause for the epidemic of aging and obesity-related disorders. We also speculate key issues that need to be addressed on how to reveal relevant brain dysfunction that underlines the development of these disorders and diseases in order to develop new treatment strategies against these health problems.
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Affiliation(s)
- Tiemin Liu
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, Institute of Metabolism and Integrative Biology, Human Phenome Institute, and Collaborative Innovation Center for Genetics and Development, Zhongshan Hospital, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Yong Xu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Chun-Xia Yi
- grid.7177.60000000084992262Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Amsterdam Gastroenterology Endocrinology Metabolism, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, Netherlands
| | - Qingchun Tong
- grid.453726.10000 0004 5906 7293Brown Foundation Institute of Molecular Medicine, Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Graduate Program in Neuroscience of MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030 USA
| | - Dongsheng Cai
- grid.251993.50000000121791997Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461 USA
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4
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Tran LT, Park S, Kim SK, Lee JS, Kim KW, Kwon O. Hypothalamic control of energy expenditure and thermogenesis. Exp Mol Med 2022; 54:358-369. [PMID: 35301430 PMCID: PMC9076616 DOI: 10.1038/s12276-022-00741-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/05/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Energy expenditure and energy intake need to be balanced to maintain proper energy homeostasis. Energy homeostasis is tightly regulated by the central nervous system, and the hypothalamus is the primary center for the regulation of energy balance. The hypothalamus exerts its effect through both humoral and neuronal mechanisms, and each hypothalamic area has a distinct role in the regulation of energy expenditure. Recent studies have advanced the understanding of the molecular regulation of energy expenditure and thermogenesis in the hypothalamus with targeted manipulation techniques of the mouse genome and neuronal function. In this review, we elucidate recent progress in understanding the mechanism of how the hypothalamus affects basal metabolism, modulates physical activity, and adapts to environmental temperature and food intake changes. The hypothalamus is a key regulator of metabolism, controlling resting metabolism, activity levels, and responses to external temperature and food intake. The balance between energy intake and expenditure must be tightly controlled, with imbalances resulting in metabolic disorders such as obesity or diabetes. Obin Kwon at Seoul National University College of Medicine and Ki Woo Kim at Yonsei University College of Dentistry, Seoul, both in South Korea, and coworkers reviewed how metabolism is regulated by the hypothalamus, a small hormone-producing brain region. They report that hormonal and neuronal signals from the hypothalamus influence the ratio of lean to fatty tissue, gender-based differences in metabolism, activity levels, and weight gain in response to food intake. They note that further studies to untangle cause-and-effect relationships and other genetic factors will improve our understanding of metabolic regulation.
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Affiliation(s)
- Le Trung Tran
- Departments of Oral Biology and Applied Biological Science, BK21 Four, Yonsei University College of Dentistry, Seoul, 03722, Korea
| | - Sohee Park
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea.,Departments of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Seul Ki Kim
- Departments of Oral Biology and Applied Biological Science, BK21 Four, Yonsei University College of Dentistry, Seoul, 03722, Korea
| | - Jin Sun Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea.,Departments of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Ki Woo Kim
- Departments of Oral Biology and Applied Biological Science, BK21 Four, Yonsei University College of Dentistry, Seoul, 03722, Korea.
| | - Obin Kwon
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea. .,Departments of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea.
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5
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Goit RK, Taylor AW, Yin Lo AC. The central melanocortin system as a treatment target for obesity and diabetes: A brief overview. Eur J Pharmacol 2022; 924:174956. [DOI: 10.1016/j.ejphar.2022.174956] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 04/01/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022]
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6
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Eerola K, Virtanen S, Vähätalo L, Ailanen L, Cai M, Hruby V, Savontaus M, Savontaus E. Hypothalamic γ-melanocyte stimulating hormone gene delivery reduces fat mass in male mice. J Endocrinol 2018; 239:19–31. [PMID: 30307151 DOI: 10.1530/joe-18-0009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
γ-Melanocyte stimulating hormone (γ-MSH) is an endogenous agonist of the melanocortin 3-receptor (MC3R). Genetic disruption of MC3Rs increases adiposity and blunts responses to fasting, suggesting that increased MC3R signaling could be physiologically beneficial in the long term. Interestingly, several studies have concluded that activation of MC3Rs is orexigenic in the short term. Therefore, we aimed to examine the short- and long-term effects of γ-MSH in the hypothalamic arcuate nucleus (ARC) on energy homeostasis and hypothesized that the effect of MC3R agonism is dependent on the state of energy balance and nutrition. Lentiviral gene delivery was used to induce a continuous expression of γ-Msh only in the ARC of male C57Bl/6N mice. Parameters of body energy homeostasis were monitored as food was changed from chow (6 weeks) to Western diet (13 weeks) and back to chow (7 weeks). The γ-MSH treatment decreased the fat mass to lean mass ratio on chow, but the effect was attenuated on Western diet. After the switch back to chow, an enhanced loss in weight (−15% vs −6%) and fat mass (−37% vs −12%) and reduced cumulative food intake were observed in γ-MSH-treated animals. Fasting-induced feeding was increased on chow diet only; however, voluntary running wheel activity on Western diet was increased. The γ-MSH treatment also modulated the expression of key neuropeptides in the ARC favoring weight loss. We have shown that a chronic treatment intended to target ARC MC3Rs modulates energy balance in nutritional state-dependent manner. Enhancement of diet-induced weight loss could be beneficial in treatment of obesity.
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Affiliation(s)
- K Eerola
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
| | - S Virtanen
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - L Vähätalo
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - L Ailanen
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Drug Research Doctoral Program, University of Turku, Turku, Finland
| | - M Cai
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - V Hruby
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - M Savontaus
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Heart Center, Turku University Hospital and University of Turku, Turku, Finland
| | - E Savontaus
- Institute of Biomedicine, Research Center for Integrative Physiology and Pharmacology and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
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7
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Mancini G, Horvath TL. Viral Vectors for Studying Brain Mechanisms that Control Energy Homeostasis. Cell Metab 2018; 27:1168-1175. [PMID: 29874565 DOI: 10.1016/j.cmet.2018.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 03/18/2018] [Accepted: 05/16/2018] [Indexed: 12/26/2022]
Abstract
Viral vectors have been shown to be potent and versatile tools for genome editing. In the present Minireview, we focus on lentiviruses and adeno-associated viruses as vectors and their use in the study of the hypothalamic circuits involved in the regulation of energy homeostasis.
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Affiliation(s)
- Giacomo Mancini
- Program in Integrative Cell Signalling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Tamas L Horvath
- Program in Integrative Cell Signalling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Anatomy and Histology, University of Veterinary Medicine, Budapest 1078, Hungary.
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8
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Kim K, Choe HK. Role of hypothalamus in aging and its underlying cellular mechanisms. Mech Ageing Dev 2018; 177:74-79. [PMID: 29729230 DOI: 10.1016/j.mad.2018.04.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/20/2018] [Accepted: 04/30/2018] [Indexed: 02/06/2023]
Abstract
Aging is characterized by a progressive loss of several physiological functions that can cause various age-related disorders. Several factors have been identified as causes of aging to elucidate the decline in functions. Various aspects of physiological deterioration are controlled by the hypothalamus, a critical brain region that connects the neuroendocrine system to physiological functions. In addition, functional alterations in a set of agouti-related peptide/neuropeptide Y (AgRP/NPY) and pro-opiomelanocortin (POMC) neurons, a set of growth hormone-releasing hormone (GHRH) and somatostatin (SST) neurons, a set of arginine vasopressin (AVP) and vasoactive intestinal peptide (VIP) neurons, and a set of gonadotropin-releasing hormone (GnRH) and kisspeptin/neurokinin B/dynorphin (KNDy) neurons contribute to age-related physiological decline in energy metabolism, hormone regulation, circadian rhythm, and reproduction, respectively. The underlying cellular mechanism for the hypothalamus-mediated aging progression comprises dysregulation of nutrient sensing, altered intercellular communication, stem cell exhaustion, loss of proteostasis, and epigenetic alterations. Furthermore, mammalian target of rapamycin (mTOR), NF-kB, hypothalamic stem cell, autophagy, and SIRT1 have been recognized as critical factors or pathways mediating the mechanism. Perhaps, further dissection of these pathways or components could provide the potential for developing a therapeutic intervention for age-related diseases or the extension of healthy lifespan.
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Affiliation(s)
- Keetae Kim
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
| | - Han Kyoung Choe
- Department of Brain and Cognitive Sciences, DGIST, Daegu, 42988, Republic of Korea.
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9
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Ando A, Gantulga D, Nakata M, Maekawa F, Dezaki K, Ishibashi S, Yada T. Weaning stage hyperglycemia induces glucose-insensitivity in arcuate POMC neurons and hyperphagia in type 2 diabetic GK rats. Neuropeptides 2018. [PMID: 29525472 DOI: 10.1016/j.npep.2018.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hyperphagia triggers and accelerates diabetes, and prevents proper dietary control of glycemia. Inversely, the impact of hyperglycemia on hyperphagia and possible mechanistic cause common for these two metabolic disorders in type 2 diabetes are less defined. The present study examined the precise developmental process of hyperglycemia and hyperphagia and explored the alterations in the hypothalamic arcuate nucleus (ARC), the primary feeding and metabolic center, in Goto-Kakizaki (GK) rats with type 2 diabetes and nearly normal body weight. At mid 3 to 4 weeks of age, GK rats first exhibited hyperglycemia, and then hyperphagia and reduced mRNA expressions for anorexigenic pro-opiomelanocortin (POMC) and glucokinase in ARC. Furthermore, [Ca2+]i responses to high glucose in ARC POMC neurons were impaired in GK rats at 4 weeks. Treating GK rats from early 3 to mid 6 weeks of age with an anti-diabetic medicine miglitol not only suppressed hyperglycemia but ameliorated hyperphagia and restored POMC mRNA expression in ARC. These results suggest that the early hyperglycemia occurring in weaning period may lead to impaired glucose sensing and neuronal activity of POMC neurons, and thereby induce hyperphagia in GK rats. Correction of hyperglycemia in the early period may prevent and/or ameliorate the progression of hyperphagia in type 2 diabetes.
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Affiliation(s)
- A Ando
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan; Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - D Gantulga
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - M Nakata
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - F Maekawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba-City, Ibaragi 305-8506, Japan
| | - K Dezaki
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - S Ishibashi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - T Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan; Kansai Electric Power Medical Research Institute, 1-5-6 Minatojimaminamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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10
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Siu JJ, Queen NJ, Liu X, Huang W, McMurphy T, Cao L. Molecular Therapy of Melanocortin-4-Receptor Obesity by an Autoregulatory BDNF Vector. Mol Ther Methods Clin Dev 2017; 7:83-95. [PMID: 29296625 PMCID: PMC5744069 DOI: 10.1016/j.omtm.2017.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 09/26/2017] [Indexed: 12/27/2022]
Abstract
Mutations in the melanocortin-4-receptor (MC4R) comprise the most common monogenic form of severe early-onset obesity, and conventional treatments are either ineffective long-term or contraindicated. Immediately downstream of MC4R-in the pathway for regulating energy balance-is brain-derived neurotrophic factor (BDNF). Our previous studies show that adeno-associated virus (AAV)-mediated hypothalamic BDNF gene transfer alleviates obesity and diabetes in both diet-induced and genetic models. To facilitate clinical translation, we developed a built-in autoregulatory system to control therapeutic gene expression mimicking the body's natural feedback systems. This autoregulatory approach leads to a sustainable plateau of body weight after substantial weight loss is achieved. Here, we examined the efficacy and safety of autoregulatory BDNF gene therapy in Mc4r heterozygous mice, which best resemble MC4R obese patients. Mc4r heterozygous mice were treated with either autoregulatory BDNF vector or YFP control and monitored for 30 weeks. BDNF gene therapy prevented the development of obesity and metabolic syndromes characterized by decreasing body weight and adiposity, suppressing food intake, alleviating hyperleptinemia and hyperinsulinemia, improving glucose and insulin tolerance, and increasing energy expenditure, without adverse cardiovascular function or behavioral disturbances. These safety and efficacy data provide preclinical evidence that BDNF gene therapy is a compelling treatment option for MC4R-deficient obese patients.
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Affiliation(s)
- Jason J. Siu
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Medical Scientist Training Program, The Ohio State University, Columbus, OH 43210, USA
| | - Nicholas J. Queen
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Xianglan Liu
- Department of Cancer Biology and 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 and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Travis McMurphy
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Lei Cao
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Medical Scientist Training Program, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
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11
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Côté I, Sakarya Y, Kirichenko N, Morgan D, Carter CS, Tümer N, Scarpace PJ. Activation of the central melanocortin system chronically reduces body mass without the necessity of long-term caloric restriction. Can J Physiol Pharmacol 2016; 95:206-214. [PMID: 28051332 DOI: 10.1139/cjpp-2016-0290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Melanotan II (MTII) is a potent appetite suppressor that rapidly reduces body mass. Given the rapid loss of anorexic response upon chronic MTII treatment, most investigations have focused on the initial physiological adaptations. However, other evidence supports MTII as a long-term modulator of energy balance that remains to be established. Therefore, we examined the chronic effects of MTII on energy homeostasis. MTII (high or low dose) or artificial cerebrospinal fluid (aCSF) was infused into the lateral ventricle of the brain of 6-month-old F344BN rats (6-7/group) over 40 days. MTII suppressed appetite in a dose-dependent manner (P < 0.05). Although food intake promptly rose back to control level, body mass was persistently reduced in both MTII groups (P < 0.01). At day 40, both MTII groups displayed lower adiposity than the aCSF animals (P < 0.01). These results show that MTII chronically reduces body mass without the requirement of long-term caloric restriction. Our study proposes that food restriction helps initiate mass loss; however, combined with a secondary pharmacological approach preserving a negative energy balance state over time may help combat obesity.
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Affiliation(s)
- I Côté
- a Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
| | - Y Sakarya
- a Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA.,b Geriatric Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - N Kirichenko
- a Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA.,b Geriatric Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - D Morgan
- c Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - C S Carter
- d Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA
| | - N Tümer
- a Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA.,b Geriatric Research, Education, and Clinical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL, USA
| | - P J Scarpace
- a Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
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12
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Mountjoy KG. Pro-Opiomelanocortin (POMC) Neurones, POMC-Derived Peptides, Melanocortin Receptors and Obesity: How Understanding of this System has Changed Over the Last Decade. J Neuroendocrinol 2015; 27:406-18. [PMID: 25872650 DOI: 10.1111/jne.12285] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/04/2015] [Accepted: 04/07/2015] [Indexed: 12/19/2022]
Abstract
Following the cloning of the melanocortin receptor and agouti protein genes, a model was developed for the central melanocortin system with respect to the regulation of energy and glucose homeostasis. This model comprised leptin regulation of melanocortin peptides and agouti-related peptide (AgRP) produced from central pro-opiomelanocortin (POMC) and AgRP neurones, respectively, as well as AgRP competitive antagonism of melanocortin peptides activating melanocortin 4 receptor (MC4R) to Gαs and the cAMP signalling pathway. In the last decade, there have been paradigm shifts in our understanding of the central melanocortin system as a result of the application of advanced new technologies, including Cre-LoxP transgenic mouse technology, pharmacogenetics and optogenetics. During this period, our understanding of G protein coupled receptor signal transduction has also dramatically changed, such that these receptors are now known to exist in the plasma membrane oscillating between various inactive and active conformational states, and the active states signal through G protein-dependent and G protein-independent pathways. The present review focuses on evidence obtained over the past decade that has changed our understanding of POMC gene expression and regulation in the central nervous system, POMC and AgRP neuronal circuitry, neuroanatomical functions of melanocortin receptors, melanocortin 3 receptor (MC3R) and MC4R, and signal transduction through MC3R and MC4R.
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Affiliation(s)
- K G Mountjoy
- Departments of Physiology and Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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Eerola K, Rinne P, Penttinen AM, Vähätalo L, Savontaus M, Savontaus E. α-MSH overexpression in the nucleus tractus solitarius decreases fat mass and elevates heart rate. J Endocrinol 2014; 222:123-36. [PMID: 24829220 DOI: 10.1530/joe-14-0064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The POMC pathway is involved in the regulation of energy and cardiovascular homeostasis in the hypothalamus and the brain stem. Although the acute effects of POMC-derived peptides in different brain locations have been elucidated, the chronic site-specific effects of distinct peptides remain to be studied. To this end, we used a lentiviral gene delivery vector to study the long-term effects of α-MSH in the nucleus tractus solitarius (NTS) of the brain stem. The α-MSH vector (LVi-α-MSH-EGFP) based on the N-terminal POMC sequence and a control vector (LVi-EGFP) were delivered into the NTS of C57BL/6N male mice fed on a western diet. Effects on body weight and composition, feeding, glucose metabolism, and hemodynamics by telemetric analyses were studied during the 12-week follow-up. The LVi-α-MSH-EGFP-treated mice had a significantly smaller gain in the fat mass compared with LVi-EGFP-injected mice. There was a small initial decrease in food intake and no differences in the physical activity. Glucose metabolism was not changed compared with the control. LVi-α-MSH-EGFP increased the heart rate (HR), which was attenuated by adrenergic blockade suggesting an increased sympathetic activity. Reduced response to muscarinic blockade suggested a decreased parasympathetic activity. Fitting with sympathetic activation, LVi-α-MSH-EGFP treatment reduced urine secretion. Thus, the results demonstrate that long-term α-MSH overexpression in the NTS attenuates diet-induced obesity. Modulation of autonomic nervous system tone increased the HR and most probably contributed to an anti-obesity effect. The results underline the key role of NTS in the α-MSH-induced long-term effects on adiposity and in regulation of sympathetic and parasympathetic activities.
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Affiliation(s)
- K Eerola
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - P Rinne
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - A M Penttinen
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - L Vähätalo
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - M Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - E Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
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Fosgerau K, Raun K, Nilsson C, Dahl K, Wulff BS. Novel α-MSH analog causes weight loss in obese rats and minipigs and improves insulin sensitivity. J Endocrinol 2014; 220:97-107. [PMID: 24204009 PMCID: PMC3888513 DOI: 10.1530/joe-13-0284] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Obesity is a major burden to people and to health care systems around the world. The aim of the study was to characterize the effect of a novel selective α-MSH analog on obesity and insulin sensitivity. The subchronic effects of the selective MC4-R peptide agonist MC4-NN1-0182 were investigated in diet-induced obese (DIO) rats and DIO minipigs by assessing the effects on food intake, energy consumption, and body weight. The acute effect of MC4-NN1-0182 on insulin sensitivity was assessed by a euglycemic-hyperinsulinemic clamp study in normal rats. Three weeks of treatment of DIO rats with MC4-NN1-0182 caused a decrease in food intake and a significant decrease in body weight 7±1%, P<0.05 compared with 3±1% increase with the vehicle control. In DIO minipigs, 8 weeks of treatment with MC4-NN1-0182 resulted in a body weight loss of 13.3±2.5 kg (13±3%), whereas the vehicle control group had gained 3.7±1.4 kg (4±1%). Finally, clamp studies in normal rats showed that acute treatment with MC4-NN1-0182 caused a significant increase in glucose disposal (Rd) compared with vehicle control (Rd, mg/kg per min, 17.0±0.7 vs 13.9±0.6, P<0.01). We demonstrate that treatment of DIO rats or minipigs with a selective MC4-R peptide agonist causes weight loss. Moreover, we have demonstrated weight-independent effects on insulin sensitivity. Our observations identify MC4 agonism as a viable target for the treatment of obesity and insulin resistance.
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Affiliation(s)
- Keld Fosgerau
- Novo Nordisk Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Maaloev, Denmark
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Eerola K, Nordlund W, Virtanen S, Dickens AM, Mattila M, Ruohonen ST, Chua SC, Wardlaw SL, Savontaus M, Savontaus E. Lentivirus-mediated α-melanocyte-stimulating hormone overexpression in the hypothalamus decreases diet induced obesity in mice. J Neuroendocrinol 2013; 25:1298-1307. [PMID: 24118213 DOI: 10.1111/jne.12109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 09/20/2013] [Accepted: 09/21/2013] [Indexed: 11/29/2022]
Abstract
Melanocyte stimulating hormone (MSH) derived from the pro-hormone pro-opiomelanocortin (POMC) has potent effects on metabolism and feeding that lead to reduced body weight in the long-term. To determine the individual roles of POMC derived peptides and their sites of action, we created a method for the delivery of single MSH peptides using lentiviral vectors and studied the long-term anti-obesity effects of hypothalamic α-MSH overexpression in mice. An α-MSH lentivirus (LVi-α-MSH-EGFP) vector carrying the N'-terminal part of POMC and the α-MSH sequence was generated and shown to produce bioactive peptide in an in vitro melanin synthesis assay. Stereotaxis was used to deliver the LVi-α-MSH-EGFP or control LVi-EGFP vector to the arcuate nucleus (ARC) of the hypothalamus of male C57Bl/6N mice fed on a high-fat diet. The effects of 6-week-treatment on body weight, food intake, glucose tolerance and organ weights were determined. Additionally, a 14-day pairfeeding study was conducted to assess whether the weight decreasing effect of the LVi-α-MSH-EGFP treatment is dependent on decreased food intake. The 6-week LVi-α-MSH-EGFP treatment reduced weight gain (8.4 ± 0.4 g versus 12.3 ± 0.6 g; P < 0.05), which was statistically significant starting from 1 week after the injections. The weight of mesenteric fat was decreased and glucose tolerance was improved compared to LVi-EGFP treated mice. Food intake was decreased during the first week in the LVi-α-MSH-EGFP treated mice but subsequently increased to the level of LVi-EGFP treated mice. The LVi-EGFP injected control mice gained more weight even when pairfed to the level of food intake by LVi-α-MSH-EGFP treated mice. We demonstrate that gene transfer of α-MSH, a single peptide product of POMC, into the ARC of the hypothalamus, reduces obesity and improves glucose tolerance, and that factors other than decreased food intake also influence the weight decreasing effects of α-MSH overexpression in the ARC. Furthermore, viral MSH vectors delivered stereotaxically provide a novel tool for further exploration of chronic site-specific effects of POMC peptides.
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Affiliation(s)
- K Eerola
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- FinPharma Doctoral Program, Drug Discovery Section, Turku, Finland
| | - W Nordlund
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - S Virtanen
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
| | - A M Dickens
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku PET Centre, Medicity/PET Preclinical Imaging, University of Turku, Turku, Finland
| | - M Mattila
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Medical Biochemistry and Genetics, University of Turku, Turku, Finland
| | - S T Ruohonen
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - S C Chua
- Albert Einstein College of Medicine, New York, NY, USA
| | - S L Wardlaw
- Department of Medicine, Columbia University College of Physicians & Surgeons, New York, NY, USA
| | - M Savontaus
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Turku Heart Center, Turku University Hospital and University of Turku, Turku, Finland
| | - E Savontaus
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
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16
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Jeong JK, Szabo G, Raso GM, Meli R, Diano S. Deletion of prolyl carboxypeptidase attenuates the metabolic effects of diet-induced obesity. Am J Physiol Endocrinol Metab 2012; 302:E1502-10. [PMID: 22454290 PMCID: PMC3378159 DOI: 10.1152/ajpendo.00544.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
α-Melanocyte-stimulating hormone (α-MSH) is a critical regulator of energy metabolism. Prolyl carboxypeptidase (PRCP) is an enzyme responsible for its degradation and inactivation. PRCP-null mice (PRCP(gt/gt)) showed elevated levels of brain α-MSH, reduced food intake, and a leaner phenotype compared with wild-type controls. In addition, they were protected against diet-induced obesity. Here, we show that PRCP(gt/gt) animals have improved metabolic parameters compared with wild-type controls under a standard chow diet (SD) as well as on a high-fat diet (HFD). Similarly to when they are exposed to SD, PRCP(gt/gt) mice exposed to HFD for 13 wk showed a leaner phenotype due to decreased fat mass, increased energy expenditure, and locomotor activity. They also showed improved insulin sensitivity and glucose tolerance compared with WT controls and a significant reduction in fasting glucose levels. These improvements occured before changes in body weight and composition were evident, suggesting that the beneficial effect of PRCP ablation is independent of the adiposity levels. In support of a reduced gluconeogenesis, liver PEPCK and G-6-Pase mRNA levels were reduced significantly in PRCP(gt/gt) compared with WT mice. A significant decrease in liver weight and hepatic triglycerides were also observed in PRCP(gt/gt) compared with WT mice. Altogether, our data suggest that PRCP is an important regulator of energy and glucose homeostasis since its deletion significantly improves metabolic parameters in mice exposed to both SD and HFD.
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Affiliation(s)
- Jin Kwon Jeong
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520-208063, USA
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Andino LM, Ryder DJ, Shapiro A, Matheny MK, Zhang Y, Judge MK, Cheng KY, Tümer N, Scarpace PJ. POMC overexpression in the ventral tegmental area ameliorates dietary obesity. J Endocrinol 2011; 210:199-207. [PMID: 21565854 DOI: 10.1530/joe-10-0418] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The activation of proopiomelanocortin (POMC) neurons in different regions of the brain, including the arcuate nucleus of the hypothalamus (ARC) and the nucleus of the solitary tract curtails feeding and attenuates body weight. In this study, we compared the effects of delivery of a recombinant adeno-associated viral (rAAV) construct encoding POMC to the ARC with delivery to the ventral tegmental area (VTA). F344×Brown Norway rats were high-fat (HF) fed for 14 days after which self-complementary rAAV constructs expressing either green fluorescent protein or the POMC gene were injected using coordinates targeting either the VTA or the ARC. Corresponding increased POMC levels were found at the predicted injection sites and subsequent α-melanocyte-stimulating hormone levels were observed. Food intake and body weight were measured for 4 months. Although caloric intake was unaltered by POMC overexpression, weight gain was tempered with POMC overexpression in either the VTA or the ARC compared with controls. There were parallel decreases in adipose tissue reserves. In addition, levels of oxygen consumption and brown adipose tissue uncoupling protein 1 were significantly elevated with POMC treatment in the VTA. Interestingly, tyrosine hydroxylase levels were increased in both the ARC and VTA with POMC overexpression in either the ARC or the VTA. In conclusion, these data indicate a role for POMC overexpression within the VTA reward center to combat HF-induced obesity.
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Affiliation(s)
- Lourdes M Andino
- Departments of Pharmacology and Therapeutics Aging and Geriatrics, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida 32610, USA
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Sousa-Ferreira L, Garrido M, Nascimento-Ferreira I, Nobrega C, Santos-Carvalho A, Álvaro AR, Rosmaninho-Salgado J, Kaster M, Kügler S, Pereira de Almeida L, Cavadas C. Moderate long-term modulation of neuropeptide Y in hypothalamic arcuate nucleus induces energy balance alterations in adult rats. PLoS One 2011; 6:e22333. [PMID: 21799827 PMCID: PMC3142146 DOI: 10.1371/journal.pone.0022333] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 06/25/2011] [Indexed: 12/30/2022] Open
Abstract
Neuropeptide Y (NPY) produced by arcuate nucleus (ARC) neurons has a strong orexigenic effect on target neurons. Hypothalamic NPY levels undergo wide-ranging oscillations during the circadian cycle and in response to fasting and peripheral hormones (from 0.25 to 10-fold change). The aim of the present study was to evaluate the impact of a moderate long-term modulation of NPY within the ARC neurons on food consumption, body weight gain and hypothalamic neuropeptides. We achieved a physiological overexpression (3.6-fold increase) and down-regulation (0.5-fold decrease) of NPY in the rat ARC by injection of AAV vectors expressing NPY and synthetic microRNA that target the NPY, respectively. Our work shows that a moderate overexpression of NPY was sufficient to induce diurnal over-feeding, sustained body weight gain and severe obesity in adult rats. Additionally, the circulating levels of leptin were elevated but the immunoreactivity (ir) of ARC neuropeptides was not in accordance (POMC-ir was unchanged and AGRP-ir increased), suggesting a disruption in the ability of ARC neurons to response to peripheral metabolic alterations. Furthermore, a dysfunction in adipocytes phenotype was observed in these obese rats. In addition, moderate down-regulation of NPY did not affect basal feeding or normal body weight gain but the response to food deprivation was compromised since fasting-induced hyperphagia was inhibited and fasting-induced decrease in locomotor activity was absent.These results highlight the importance of the physiological ARC NPY levels oscillations on feeding regulation, fasting response and body weight preservation, and are important for the design of therapeutic interventions for obesity that include the NPY.
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Affiliation(s)
- Lígia Sousa-Ferreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Manuel Garrido
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Neurology, Viral Vectors Laboratory, University Medicine Göttingen, Göttingen, Germany
| | - Isabel Nascimento-Ferreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Clévio Nobrega
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Santos-Carvalho
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Ana Rita Álvaro
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Biology and Environment, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | | | - Manuella Kaster
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Sebastian Kügler
- Department of Neurology, Viral Vectors Laboratory, University Medicine Göttingen, Göttingen, Germany
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Claudia Cavadas
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
- * E-mail:
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Leckstrom A, Lew PS, Poritsanos NJ, Mizuno TM. Treatment with a melanocortin agonist improves abnormal lipid metabolism in streptozotocin-induced diabetic mice. Neuropeptides 2011; 45:123-9. [PMID: 21216462 DOI: 10.1016/j.npep.2010.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/28/2010] [Accepted: 12/17/2010] [Indexed: 01/09/2023]
Abstract
Impairments in leptin-melanocortin signaling are associated with insulin-deficient diabetes and leptin treatment has been shown to be effective in reversing hyperglycemia in animal models of type 1 diabetes. Therefore, we hypothesized that enhanced central melanocortin signaling reverses the metabolic impairments associated with type 1 diabetes. To address this hypothesis, streptozotocin (STZ)-induced diabetic mice were treated with daily intracerebroventricular injection of MTII, a melanocortin agonist, for 11days. STZ-induced hyperglycemia and glucose intolerance were not improved by MTII treatment. MTII treatment did not alter expression levels of genes encoding gluconeogenic enzymes including glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), in the liver of diabetic mice. Skeletal muscle and white adipose tissue glucose transporter 4 (GLUT4) mRNA levels were not altered by MTII treatment in diabetic mice. In contrast, serum nonesterified fatty acid (NEFA) levels were significantly increased in STZ-induced diabetic mice compared to non-diabetic control mice and MTII treatment significantly reduced serum NEFA levels in diabetic mice. MTII treatment also significantly reduced expression levels of hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) mRNA in white adipose tissue of diabetic mice without a significant change in serum insulin levels. Expression levels of lipoprotein lipase (LPL) and fatty acid translocase (FAT/CD36) mRNA in white adipose tissue and skeletal muscle were not changed by MTII treatment. These data suggest that central melanocortin signaling regulates lipid metabolism and that enhancing central melanocortin signaling is effective in reversing abnormal lipid metabolism, but not carbohydrate metabolism, at least partly by reducing lipolysis in type 1 diabetes.
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Affiliation(s)
- Arnold Leckstrom
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, Manitoba, Canada R3E0J9
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Zhang Y, Rodrigues E, Li G, Gao Y, King M, Carter CS, Tumer N, Cheng KY, Scarpace PJ. Simultaneous POMC gene transfer to hypothalamus and brainstem increases physical activity, lipolysis and reduces adult-onset obesity. Eur J Neurosci 2011; 33:1541-50. [PMID: 21366729 DOI: 10.1111/j.1460-9568.2011.07633.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pro-opiomelanocortin (POMC) neurons are identified in two brain sites, the arcuate nucleus of the hypothalamus and nucleus of the solitary tract (NTS) in brainstem. Earlier pharmacological and POMC gene transfer studies demonstrate that melanocortin activation in either site alone improves insulin sensitivity and reduces obesity. The present study, for the first time, investigated the long-term efficacy of POMC gene transfer concurrently into both sites in the regulation of energy metabolism in aged F344xBN rats bearing adult-onset obesity. Pair feeding was included to reveal food-independent POMC impact on energy expenditure. We introduced adeno-associated virus encoding either POMC or green fluorescence protein to the two brain areas in 22-month-old rats, then recorded food intake and body weight, assessed oxygen consumption, serum leptin, insulin and glucose, tested voluntary wheel running, analysed POMC expression, and examined fat metabolism in brown and white adipose tissues. POMC mRNA was significantly increased in both the hypothalamus and NTS region at termination. Relative to pair feeding, POMC caused sustained weight reduction and additional fat loss, lowered fasting insulin and glucose, and augmented white fat hormone-sensitive lipase activity and brown fat uncoupling protein 1 level. By wheel running assessment, the POMC animals ran twice the distance as the Control or pair-fed rats. Thus, the dual-site POMC treatment ameliorated adult-onset obesity effectively, involving a moderate hypophagia lasting ∼60 days, enhanced lipolysis and thermogenesis, and increased physical activity in the form of voluntary wheel running. The latter finding provides a clue for countering age-related decline in physical activity.
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Affiliation(s)
- Yi Zhang
- Malcom Randall Veterans Affairs Medical Center, Gainesville, FL 32608, USA.
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de Backer MWA, Brans MAD, Luijendijk MCM, Garner KM, van den Heuvel DMA, Pasterkamp RJ, Adan RAH. Neuropeptide delivery to the brain: a von Willebrand factor signal peptide to direct neuropeptide secretion. BMC Neurosci 2010; 11:94. [PMID: 20701764 PMCID: PMC2928777 DOI: 10.1186/1471-2202-11-94] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 08/11/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion. RESULTS We fused the signal peptide from the Von Willebrand Factor (VWF) to a furin site followed by a processed form of the Agouti related protein (AgRP), AgRP(83-132) or alpha-melanocyte stimulating hormone. In vitro, these minigenes were secreted and biologically active. Additionally, the proteins of the minigenes were not transported into projections of primary neurons, thereby ensuring local release. In vivo administration of VWF-AgRP(83-132), using an adeno-associated viral vector as a delivery vehicle, into the paraventricular hypothalamus increased body weight and food intake of these rats compared to rats which received a control vector. CONCLUSIONS This study demonstrated that removal of the N-terminal part of full length AgRP and addition of a VWF signal peptide is a successful strategy to deliver neuropeptide minigenes to the brain and establish local neuropeptide secretion.
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Affiliation(s)
- Marijke W A de Backer
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, Utrecht University Medical Centre Utrecht, Utrecht, the Netherlands
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22
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Abstract
The melanocortin-4 receptor (MC4R) was cloned in 1993 by degenerate PCR; however, its function was unknown. Subsequent studies suggest that the MC4R might be involved in regulating energy homeostasis. This hypothesis was confirmed in 1997 by a series of seminal studies in mice. In 1998, human genetic studies demonstrated that mutations in the MC4R gene can cause monogenic obesity. We now know that mutations in the MC4R are the most common monogenic form of obesity, with more than 150 distinct mutations reported thus far. This review will summarize the studies on the MC4R, from its cloning and tissue distribution to its physiological roles in regulating energy homeostasis, cachexia, cardiovascular function, glucose and lipid homeostasis, reproduction and sexual function, drug abuse, pain perception, brain inflammation, and anxiety. I will then review the studies on the pharmacology of the receptor, including ligand binding and receptor activation, signaling pathways, as well as its regulation. Finally, the pathophysiology of the MC4R in obesity pathogenesis will be reviewed. Functional studies of the mutant MC4Rs and the therapeutic implications, including small molecules in correcting binding and signaling defect, and their potential as pharmacological chaperones in rescuing intracellularly retained mutants, will be highlighted.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology, Auburn University, Alabama 36849-5519, USA.
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Pro-opiomelanocortin gene transfer to the nucleus of the solitary track but not arcuate nucleus ameliorates chronic diet-induced obesity. Neuroscience 2010; 169:1662-71. [PMID: 20538045 DOI: 10.1016/j.neuroscience.2010.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/27/2010] [Accepted: 06/01/2010] [Indexed: 11/20/2022]
Abstract
Short-term pharmacological melanocortin activation deters diet-induced obesity (DIO) effectively in rodents. However, whether central pro-opiomelanocortin (POMC) gene transfer targeted to the hypothalamus or hindbrain nucleus of the solitary track (NTS) can combat chronic dietary obesity has not been investigated. Four-weeks-old Sprague-Dawley rats were fed a high fat diet for 5 months, and then injected with either the POMC or control vector into the hypothalamus or NTS, and body weight and food intake recorded for 68 days. Insulin sensitivity, glucose metabolism and adrenal indicators of central sympathetic activation were measured, and voluntary wheel running (WR) assessed. Whereas the NTS POMC-treatment decreased cumulative food consumption and caused a sustained weight reduction over 68 days, the hypothalamic POMC-treatment did not alter cumulative food intake and produced weight loss only in the first 25 days. At death, only the NTS-POMC rats had a significant decrease in fat mass. They also displayed enhanced glucose tolerance, lowered fasting insulin and increased QUICK value, and elevated adrenal indicators of central sympathetic activation. Moreover, the NTS-POMC animals exhibited a near 20% increase in distance ran relative to the respective controls, but the ARC-POMC rats did not. In conclusion, POMC gene transfer to the NTS caused modest anorexia, persistent weight loss, improved insulin sensitivity, and increased propensity for WR in DIO rats. These metabolic improvements may involve stimulation of energy expenditure via centrally regulated sympathetic outflow. The similar POMC treatment in the hypothalamus had minimal long-term physiological or metabolic impact. Thus, melanocortin activation in the brainstem NTS region effectively ameliorates chronic dietary obesity whilst that in the hypothalamus fails to do so.
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Holness MJ, Caton PW, Sugden MC. Acute and long-term nutrient-led modifications of gene expression: Potential role of SIRT1 as a central co-ordinator of short and longer-term programming of tissue function. Nutrition 2010; 26:491-501. [DOI: 10.1016/j.nut.2009.09.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 09/17/2009] [Indexed: 12/30/2022]
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25
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Zhang Y, Collazo R, Gao Y, Li G, Scarpace PJ. Intermittent MTII application evokes repeated anorexia and robust fat and weight loss. Peptides 2010; 31:639-43. [PMID: 20034526 PMCID: PMC2860181 DOI: 10.1016/j.peptides.2009.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 12/12/2009] [Accepted: 12/13/2009] [Indexed: 10/20/2022]
Abstract
Central melanocortins (MC) evoke potent but transient anorectic responses with tachyphylaxis developing within days. We hypothesized that intermittent therapy using the MC analog, melanotan II (MTII), would minimize the tachyphylaxis and enhance the long-term efficacy of MTII treatment. F344/BN rats were infused with MTII or vehicle into the lateral ventricle by mini pump for 14 days. Half the MTII-infused rats were then given vehicle (MTII-On/Off), while the remaining received fresh MTII (MTII-On) for 10 days. Finally, pumps in both groups were replaced with ones containing fresh MTII for an additional 6 days. The first MTII application induced a 30% food reduction that attenuated within 5 days. Reapplication of MTII in MTII-On/Off rats, after the off period, invoked a new and equally robust anorectic response while continuation of MTII supplement in the MTII-On group did not change food intake from the control level. Body weights decreased similarly in both MTII groups at termination (day 30). Hypothalamic MC3 receptor, AgRP, and POMC expressions were unchanged, but MC4 receptor expression was diminished by 25%, and adiposity reduced by 80% in both MTII groups. Acetyl-CoA carboxylase 1 phosphorylation was elevated in perirenal fat by over 10 fold with either MTII treatment. In conclusion, intermittent MTII treatment preserves anorectic responses but does not prevent tachyphylaxis, whereas constant MTII application blunts further food response after the initial tachyphylaxis. Either form of MTII administration results in significant weight and adiposity reductions, involving perhaps fatty acid oxidation within specific adipose tissues.
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Affiliation(s)
- Yi Zhang
- Research Department, Malcom Randall Veterans Affairs Medical Center-NF/SG HSC, Rm E585-1, 1601 SW Archer Road, Gainesville, FL 32608, USA.
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26
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Schulz C, Paulus K, Lobmann R, Dallman M, Lehnert H. Endogenous ACTH, not only alpha-melanocyte-stimulating hormone, reduces food intake mediated by hypothalamic mechanisms. Am J Physiol Endocrinol Metab 2010; 298:E237-44. [PMID: 19920221 DOI: 10.1152/ajpendo.00408.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
ACTH and alpha-melanocyte-stimulating hormone (alpha-MSH) are both consecutively processed from proopiomelanocortin (POMC), which is synthesized in hypothalamic arcuate neurons innervating the paraventricular nuclei (PVN). POMC secretion/synthesis is regulated by energy availability. ACTH and alpha-MSH bind with equal affinity to melanocortin-4 receptors and elicit similar effects on signal transduction in-vitro. Endogenous alpha-MSH thus far is believed to be the major physiological agonist and to act in an anorexigenic manner. Until now, it was fully unknown whether endogenous ACTH is also involved in the regulation of appetite and food intake. In this study in rats, we now show that icv ACTH as well as alpha-MSH possess anorexigenic effects in the PVN or areas in close proximity in vivo and that the effect of ACTH is direct and not mediated via alpha-MSH. We investigated the roles of endogenous ACTH and alpha-MSH by PVN application of the respective antibodies under different physiological conditions. In satiated rats with high levels of ACTH and alpha-MSH in the PVN, antibody administration increased food intake and body weight gain; hungry animals were unaffected. Finally, repeated injections of ACTH antibodies into PVN resulted in persistently increased food intake during the light period. These data now provide robust evidence that endogenous ACTH without further processing acts in the PVN or areas in close proximity to reduce food intake under conditions of feeding-induced satiety.
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Affiliation(s)
- Carla Schulz
- Department of Internal Medicine I, Luebeck University, Germany.
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27
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Zhang J, Scarpace PJ. The soluble leptin receptor neutralizes leptin-mediated STAT3 signalling and anorexic responses in vivo. Br J Pharmacol 2009; 158:475-82. [PMID: 19422379 DOI: 10.1111/j.1476-5381.2009.00246.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The soluble leptin receptor (SLR) is the major, circulating, leptin-binding protein and, in vitro, the SLR inhibits leptin-binding to cell surface receptors. Here we assessed the effects of the SLR on physiological responses to leptin, in vivo. EXPERIMENTAL APPROACH SLR and leptin were given as a single injection (intracerebroventricularly, i.c.v.) or by central (i.c.v.) and peripheral (s.c.) infusion to normal adult F344XBN rats. Phosphorylation of hypothalamic STAT3 (Western blot), food intake and body weight, and the thermogenic response in brown adipose tissue (BAT) were measured. KEY RESULTS Acute central co-administration of SLR (13.5 microg) and leptin (90 ng) blocked the threefold increase in hypothalamic STAT3 phosphorylation induced by leptin alone, 1 h after the injections. Peripheral leptin infusion (0.1 mg day(-1) for 7 days; s.c.) induced a significant reduction in food intake and body weight, which were partially blocked with a simultaneous central infusion of SLR (4.3 microg day(-1); i.c.v.). In a second experiment, SLR central infusion alone (5.5 microg day(-1)) increased food intake and body weight, suggesting that the SLR was able to neutralize endogenous leptin in the brain. This dose of SLR, infused together with a lower dose of peripheral leptin (0.05 mg day(-1)), abolished the thermogenic response in BAT, but the anorexic responses and weight reduction were only partially attenuated. CONCLUSIONS These results provide direct evidence that the SLR neutralizes leptin, endogenous or exogenous, in vivo. By neutralizing leptin, the SLR may play a regulatory role in energy homeostasis.
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Affiliation(s)
- Jiejin Zhang
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610, USA
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28
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Mounien L, Do Rego JC, Bizet P, Boutelet I, Gourcerol G, Fournier A, Brabet P, Costentin J, Vaudry H, Jégou S. Pituitary adenylate cyclase-activating polypeptide inhibits food intake in mice through activation of the hypothalamic melanocortin system. Neuropsychopharmacology 2009; 34:424-35. [PMID: 18536705 DOI: 10.1038/npp.2008.73] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) and the proopiomelanocortin (POMC)-derived peptide, alpha-melanocyte-stimulating hormone (alpha-MSH), exert anorexigenic activities. While alpha-MSH is known to inhibit food intake and stimulate catabolism via activation of the central melanocortin-receptor MC4-R, little is known regarding the mechanism by which PACAP inhibits food consumption. We have recently found that, in the arcuate nucleus of the hypothalamus, a high proportion of POMC neurons express PACAP receptors. This observation led us to investigate whether PACAP may inhibit food intake through a POMC-dependent mechanism. In mice deprived of food for 18 h, intracerebroventricular administration of PACAP significantly reduced food intake after 30 min, and this effect was reversed by the PACAP antagonist PACAP6-38. In contrast, vasoactive intestinal polypeptide did not affect feeding behavior. Pretreatment with the MC3-R/MC4-R antagonist SHU9119 significantly reduced the effect of PACAP on food consumption. Central administration of PACAP induced c-Fos mRNA expression and increased the proportion of POMC neuron-expressing c-Fos mRNA in the arcuate nucleus. Furthermore, PACAP provoked an increase in POMC and MC4-R mRNA expression in the hypothalamus, while MC3-R mRNA level was not affected. POMC mRNA level in the arcuate nucleus of PACAP-specific receptor (PAC1-R) knock-out mice was reduced as compared with wild-type animals. Finally, i.c.v. injection of PACAP provoked a significant increase in plasma glucose level. Altogether, these results indicate that PACAP, acting through PAC1-R, may inhibit food intake via a melanocortin-dependent pathway. These data also suggest a central action of PACAP in the control of glucose metabolism.
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Affiliation(s)
- Lourdes Mounien
- INSERM U 413, Laboratory of Cellular and Molecular Neuroendocrinology, University of Rouen, Mont-Saint-Aignan, France
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29
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Tiesjema B, Merkestein M, Garner KM, de Krom M, Adan RAH. Multimeric α-MSH has increased efficacy to activate the melanocortin MC4 receptor. Eur J Pharmacol 2008; 585:24-30. [PMID: 18378226 DOI: 10.1016/j.ejphar.2008.02.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 02/11/2008] [Accepted: 02/12/2008] [Indexed: 11/19/2022]
Affiliation(s)
- Birgitte Tiesjema
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, The Netherlands
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30
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Kiuru M, Crystal RG. Progress and prospects: gene therapy for performance and appearance enhancement. Gene Ther 2008; 15:329-37. [DOI: 10.1038/sj.gt.3303100] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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31
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Abstract
PURPOSE OF REVIEW Obesity is associated with many health problems and its prevalence is rapidly increasing worldwide. Very few pharmaceutical compounds are available for obesity treatment. Strategies for the development of compounds can be targeted to the outcomes of reduced dietary energy intake and/or increased energy expenditure/thermogenesis. In this review, we focus on recent discoveries that advance our understanding of mitochondrial uncoupling as a target for the treatment of obesity. There are various mechanisms whereby uncoupling can occur and for the purpose of this review, we elaborate upon the uncoupling that can occur (1) through the original uncoupling protein, UCP1, in brown adipocytes, or in 'converted' white adipose tissue, and (2) in skeletal muscle. RECENT FINDINGS Studies have identified a number of novel receptors and regulatory proteins involved in the emergence of brown adipocytes in white adipose tissue. Molecular and pharmacologic approaches in knockout and transgenic mice have demonstrated their relevance to obesity treatment. Recent research into uncoupling mechanisms in skeletal muscle indicates that uncoupling can occur through basal and inducible processes. SUMMARY Uncoupling is a naturally occurring phenomenon whose underlying mechanisms require substantial further study for the development of antiobesity therapies.
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Affiliation(s)
- Sheila Costford
- Department of Biochemistry Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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32
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Coll AP. Effects of pro-opiomelanocortin (POMC) on food intake and body weight: mechanisms and therapeutic potential? Clin Sci (Lond) 2007; 113:171-82. [PMID: 17623013 DOI: 10.1042/cs20070105] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
POMC (pro-opiomelanocortin) is a complex polypeptide precursor which is cleaved into smaller biologically active peptides such as the melanocortins, α-, β- and γ-melanocyte-stimulating hormone. Data from human genetic and murine studies convincingly show that an intact central melanocortin signalling pathway is critical for normal energy homoeostasis. Not only does a loss of normal melanocortin signalling lead to obesity, but there are also data implicating increased melanocortin activity in the pathogenesis of cachexia. The study of POMC biology has lead to some fundamental insights into the mechanisms controlling food intake and body weight. This increased understanding of the physiological roles of the melanocortin system has opened up the potential for the design and development of rational therapies to treat perturbations in energy homoeostasis.
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Affiliation(s)
- Anthony P Coll
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK.
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33
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Li G, Zhang Y, Rodrigues E, Zheng D, Matheny M, Cheng KY, Scarpace PJ. Melanocortin activation of nucleus of the solitary tract avoids anorectic tachyphylaxis and induces prolonged weight loss. Am J Physiol Endocrinol Metab 2007; 293:E252-8. [PMID: 17389713 DOI: 10.1152/ajpendo.00451.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine the role of the brain stem melanocortin system in long-term energy regulation, we assessed the effects of overproduction of proopiomelanocortin (POMC) in the caudal brain stem of F344xBN rats with adult-onset obesity. Recombinant adeno-associated viral vector encoding POMC gene was delivered to the nucleus of solitary tract (NTS) in the hindbrain, and food intake, body weight, glucose and fat metabolism, brown adipose tissue thermogenesis, and mRNA levels of neuropeptides and melanocortin receptors were assessed. POMC delivery resulted in sustained reduction in food intake and body weight over 42 days and improved insulin sensitivity. At death, in recombinant adeno-associated viral vector-POMC-treated rats vs. control rats, alpha-melanocyte-stimulating hormone in NTS increased nearly 21-fold, whereas hypothalamic alpha-melanocyte-stimulating hormone remained unchanged. Visceral adiposity decreased by 37%; tissue triglyceride content diminished by 26% and 47% in liver and muscle, respectively; serum triglyceride and nonesterified fatty acids were reduced by 35% and 34%, respectively; phosphorylation of acetyl-CoA carboxylase was elevated by 63% in soleus muscle; brown adipose tissue uncoupling protein 1 increased by 30%; and melanocortin 3 receptor expression declined by 60%, whereas neuropeptide Y, agouti-related protein, and MC4 receptor mRNA levels were unchanged in the NTS. In conclusion, POMC overexpression in the NTS produces a characteristic unabated hypophagia that is uniquely different from the anorexic tachyphylaxis following POMC overexpression in the hypothalamus. The sustained anorectic response may result from absence of compensatory elements in the NTS, such as increased agouti-related protein expression, suggesting melanocortin activation of the brain stem may be a viable strategy to alleviate obesity.
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Affiliation(s)
- Gang Li
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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34
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Li G, Zhang Y, Cheng KY, Scarpace PJ. Lean rats with hypothalamic pro-opiomelanocortin overexpression exhibit greater diet-induced obesity and impaired central melanocortin responsiveness. Diabetologia 2007; 50:1490-9. [PMID: 17505816 DOI: 10.1007/s00125-007-0685-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/15/2007] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Central pro-opiomelanocortin (Pomc) gene therapy ameliorates genetic- or age-related obesity. We hypothesised that this treatment would delay or prevent dietary obesity in young, lean rats. MATERIALS AND METHODS Recombinant adeno-associated virus encoding Pomc (rAAV-Pomc) was delivered bilaterally into the basomedial hypothalamus of lean rats for 42 days. Food intake, body weight, serum hormones, brown adipose tissue (BAT) uncoupling protein 1 (UCP1) and mRNA levels of hypothalamic neuropeptides and melanocortin receptors were assessed. Beginning on day 43, half of the rats remained on chow while the others received a high-fat diet for 89 days. We examined energy balance and responsiveness to the melanocortin agonist melanotan II (MTII) or the antagonist SHU9119. RESULTS Pomc gene delivery produced elevated hypothalamic Pomc mRNA (fourfold) and alpha-melanocyte-stimulating hormone levels in the arcuate nucleus (twofold). Food intake and body weight were not altered by rAAV-Pomc in rats fed standard-chow. In rAAV-Pomc rats at day 42, perirenal fat and serum leptin decreased but overall visceral adiposity did not; expression of the hypothalamic agouti-related protein (Agrp) mRNA was elevated, whereas expression of melanocortin 3 and 4 receptor mRNA was reduced; BAT UCP1 protein increased nearly fourfold. The rAAV-Pomc rats fed the high-fat diet consumed more energy and gained more body weight compared with chow- or high-fat-fed controls that did not receive Pomc gene delivery. The anorexic response to MTII was impaired, whereas the orexigenic effect of SHU9119 was enhanced by rAAV-Pomc pretreatment. CONCLUSIONS/INTERPRETATION Delivery of the Pomc gene alters energy homeostasis in lean rats, predisposing them to diet-induced obesity. Diminished hypothalamic melanocortin receptors, increased Agrp expression, and potential rewiring of brain circuits may underlie the exacerbated obesity.
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Affiliation(s)
- G Li
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Box 100267, Gainesville, FL 32610, USA
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35
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Lee M, Kim A, Chua SC, Obici S, Wardlaw SL. Transgenic MSH overexpression attenuates the metabolic effects of a high-fat diet. Am J Physiol Endocrinol Metab 2007; 293:E121-31. [PMID: 17374695 DOI: 10.1152/ajpendo.00555.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine whether long-term melanocortinergic activation can attenuate the metabolic effects of a high fat diet, mice overexpressing an NH(2)-terminal POMC transgene that includes alpha- and gamma(3)-MSH were studied on either a 10% low-fat diet (LFD) or 45% high-fat diet (HFD). Weight gain was modestly reduced in transgenic (Tg-MSH) male and female mice vs. wild type (WT) on HFD (P < 0.05) but not LFD. Substantial reductions in body fat percentage were found in both male and female Tg-MSH mice on LFD (P < 0.05) and were more pronounced on HFD (P < 0.001). These changes occurred in the absence of significant feeding differences in most groups, consistent with effects of Tg-MSH on energy expenditure and partitioning. This is supported by indirect calorimetry studies demonstrating higher resting oxygen consumption and lower RQ in Tg-MSH mice on the HFD. Tg-MSH mice had lower fasting insulin levels and improved glucose tolerance on both diets. Histological and biochemical analyses revealed that hepatic fat accumulation was markedly reduced in Tg-MSH mice on the HFD. Tg-MSH also attenuated the increase in corticosterone induced by the HFD. Higher levels of Agrp mRNA, which might counteract effects of the transgene, were measured in Tg-MSH mice on LFD (P = 0.02) but not HFD. These data show that long-term melanocortin activation reduces body weight, adiposity, and hepatic fat accumulation and improves glucose metabolism, particularly in the setting of diet-induced obesity. Our results suggest that long-term melanocortinergic activation could serve as a potential strategy for the treatment of obesity and its deleterious metabolic consequences.
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Affiliation(s)
- Michelle Lee
- Department of Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th St., New York, NY 10032, USA
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36
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Abstract
The use of modern molecular biology tools in deciphering the perturbed biochemistry and physiology underlying the obese state has proven invaluable. Identifying the hypothalamic leptin/melanocortin pathway as critical in many cases of monogenic obesity has permitted targeted, hypothesis-driven experiments to be performed, and has implicated new candidates as causative for previously uncharacterized clinical cases of obesity. Meanwhile, the effects of mutations in the melanocortin-4 receptor gene, for which the obese phenotype varies in the degree of severity among individuals, are now thought to be influenced by one's environmental surroundings. Molecular approaches have revealed that syndromes (Prader-Willi and Bardet-Biedl) previously assumed to be controlled by a single gene are, conversely, regulated by multiple elements. Finally, the application of comprehensive profiling technologies coupled with creative statistical analyses has revealed that interactions between genetic and environmental factors are responsible for the common obesity currently challenging many Westernized societies. As such, an improved understanding of the different “types” of obesity not only permits the development of potential therapies, but also proposes novel and often unexpected directions in deciphering the dysfunctional state of obesity.
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Knauf C, Rieusset J, Foretz M, Cani PD, Uldry M, Hosokawa M, Martinez E, Bringart M, Waget A, Kersten S, Desvergne B, Gremlich S, Wahli W, Seydoux J, Delzenne NM, Thorens B, Burcelin R. Peroxisome proliferator-activated receptor-alpha-null mice have increased white adipose tissue glucose utilization, GLUT4, and fat mass: Role in liver and brain. Endocrinology 2006; 147:4067-78. [PMID: 16777972 DOI: 10.1210/en.2005-1536] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Activation of the peroxisome proliferator-activated receptor (PPAR)-alpha increases lipid catabolism and lowers the concentration of circulating lipid, but its role in the control of glucose metabolism is not as clearly established. Here we compared PPARalpha knockout mice with wild type and confirmed that the former developed hypoglycemia during fasting. This was associated with only a slight increase in insulin sensitivity but a dramatic increase in whole-body and adipose tissue glucose use rates in the fasting state. The white sc and visceral fat depots were larger due to an increase in the size and number of adipocytes, and their level of GLUT4 expression was higher and no longer regulated by the fed-to-fast transition. To evaluate whether these adipocyte deregulations were secondary to the absence of PPARalpha from liver, we reexpresssed this transcription factor in the liver of knockout mice using recombinant adenoviruses. Whereas more than 90% of the hepatocytes were infected and PPARalpha expression was restored to normal levels, the whole-body glucose use rate remained elevated. Next, to evaluate whether brain PPARalpha could affect glucose homeostasis, we activated brain PPARalpha in wild-type mice by infusing WY14643 into the lateral ventricle and showed that whole-body glucose use was reduced. Hence, our data show that PPARalpha is involved in the regulation of glucose homeostasis, insulin sensitivity, fat accumulation, and adipose tissue glucose use by a mechanism that does not require PPARalpha expression in the liver. By contrast, activation of PPARalpha in the brain stimulates peripheral glucose use. This suggests that the alteration in adipocyte glucose metabolism in the knockout mice may result from the absence of PPARalpha in the brain.
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Affiliation(s)
- Claude Knauf
- Unit Mixté de Recherche, 5018, Centre National de la Recherche Scientifique-University Paul Sabatier, IFR 31, Bt L1 Rue J. Poulhès, 31403 Toulouse, France
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38
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Abstract
Although the presence of hyperleptinemia with leptin resistance and obesity has long been recognized, a causal role of elevated leptin in these biological states remains unclear. This article summarizes some recent work from our laboratory supporting the concept that leptin, in and of itself, promotes leptin resistance and such resistance compounds the metabolic impact of diet-induced obesity. Results from multiple studies demonstrate that (1) chronically elevated central leptin decreases hypothalamic leptin receptor expression and protein levels and impairs leptin signaling; (2) leptin resistance and obesity are associated with reduced leptin receptors and diminished maximal leptin signaling capacity; and (3) leptin resistance confers increased susceptibility to diet-induced obesity. In essence, the augmented leptin accompanying obesity contributes to leptin resistance, and this leptin resistance promotes further obesity, leading to a vicious cycle of escalating metabolic devastation.
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Affiliation(s)
- Yi Zhang
- Research Service, Department of Veterans Affairs Medical Center, Gainesville, FL 32608, USA
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39
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Warrington KH, Herzog RW. Treatment of human disease by adeno-associated viral gene transfer. Hum Genet 2006; 119:571-603. [PMID: 16612615 DOI: 10.1007/s00439-006-0165-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 02/28/2006] [Indexed: 11/24/2022]
Abstract
During the past decade, in vivo administration of viral gene transfer vectors for treatment of numerous human diseases has been brought from bench to bedside in the form of clinical trials, mostly aimed at establishing the safety of the protocol. In preclinical studies in animal models of human disease, adeno-associated viral (AAV) vectors have emerged as a favored gene transfer system for this approach. These vectors are derived from a replication-deficient, non-pathogenic parvovirus with a single-stranded DNA genome. Efficient gene transfer to numerous target cells and tissues has been described. AAV is particularly efficient in transduction of non-dividing cells, and the vector genome persists predominantly in episomal forms. Substantial correction, and in some instances complete cure, of genetic disease has been obtained in animal models of hemophilia, lysosomal storage disorders, retinal diseases, disorders of the central nervous system, and other diseases. Therapeutic expression often lasted for months to years. Treatments of genetic disorders, cancer, and other acquired diseases are summarized in this review. Vector development, results in animals, early clinical experience, as well as potential hurdles and challenges are discussed.
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Affiliation(s)
- Kenneth H Warrington
- Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL 32615-9586, USA
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