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Liu Z, Xiao T, Liu H. Leptin signaling and its central role in energy homeostasis. Front Neurosci 2023; 17:1238528. [PMID: 38027481 PMCID: PMC10644276 DOI: 10.3389/fnins.2023.1238528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
Leptin plays a critical role in regulating appetite, energy expenditure and body weight, making it a key factor in maintaining a healthy balance. Despite numerous efforts to develop therapeutic interventions targeting leptin signaling, their effectiveness has been limited, underscoring the importance of gaining a better understanding of the mechanisms through which leptin exerts its functions. While the hypothalamus is widely recognized as the primary site responsible for the appetite-suppressing and weight-reducing effects of leptin, other brain regions have also been increasingly investigated for their involvement in mediating leptin's action. In this review, we summarize leptin signaling pathways and the neural networks that mediate the effects of leptin, with a specific emphasis on energy homeostasis.
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Affiliation(s)
- Zhaoxun Liu
- Nursing Department, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Emergency, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Tao Xiao
- Nursing Department, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hailan Liu
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
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2
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Wu Z, Martinez ME, DeMambro V, Francois M, Hernandez A. Developmental thyroid hormone action on pro-opiomelanocortin-expressing cells programs hypothalamic BMPR1A depletion and brown fat activation. J Mol Cell Biol 2023; 14:mjac078. [PMID: 36581316 PMCID: PMC9982511 DOI: 10.1093/jmcb/mjac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/21/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Thyroid hormone excess secondary to global type 3 deiodinase (DIO3) deficiency leads to increased locomotor activity and reduced adiposity, but also to concurrent alterations in parameters of the leptin-melanocortin system that would predict obesity. To distinguish the underlying contributions to the energy balance phenotype of DIO3 deficiency, we generated mice with thyroid hormone excess targeted to pro-opiomelanocortin (POMC)-expressing cells via cell-specific DIO3 inactivation. These mice exhibit a male-specific phenotype of reduced hypothalamic Pomc expression, hyperphagia, and increased activity in brown adipose tissue, with adiposity and serum levels of leptin and thyroid hormones remained normal. These male mice also manifest a marked and widespread hypothalamic reduction in the expression of bone morphogenetic receptor 1a (BMPR1A), which has been shown to cause similar phenotypes when inactivated in POMC-expressing cells. Our results indicate that developmental overexposure to thyroid hormone in POMC-expressing cells programs energy balance mechanisms in a sexually dimorphic manner by suppressing adult hypothalamic BMPR1A expression.
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Affiliation(s)
- Zhaofei Wu
- MaineHealth Institute for Research, Center for Molecular Medicine, MaineHealth, Scarborough, ME 04074, USA
| | - M Elena Martinez
- MaineHealth Institute for Research, Center for Molecular Medicine, MaineHealth, Scarborough, ME 04074, USA
| | - Victoria DeMambro
- MaineHealth Institute for Research, Center for Molecular Medicine, MaineHealth, Scarborough, ME 04074, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | - Marie Francois
- Naomi Berrie Diabetes Center, Division of Molecular Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Arturo Hernandez
- MaineHealth Institute for Research, Center for Molecular Medicine, MaineHealth, Scarborough, ME 04074, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
- Department of Medicine, Tufts University School of Medicine, Boston, MA 02111, USA
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3
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Gaitonde KD, Andrabi M, Burger CA, D'Souza SP, Vemaraju S, Koritala BSC, Smith DF, Lang RA. Diurnal regulation of metabolism by Gs-alpha in hypothalamic QPLOT neurons. PLoS One 2023; 18:e0284824. [PMID: 37141220 PMCID: PMC10159165 DOI: 10.1371/journal.pone.0284824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 04/09/2023] [Indexed: 05/05/2023] Open
Abstract
Neurons in the hypothalamic preoptic area (POA) regulate multiple homeostatic processes, including thermoregulation and sleep, by sensing afferent input and modulating sympathetic nervous system output. The POA has an autonomous circadian clock and may also receive circadian signals indirectly from the suprachiasmatic nucleus. We have previously defined a subset of neurons in the POA termed QPLOT neurons that are identified by the expression of molecular markers (Qrfp, Ptger3, LepR, Opn5, Tacr3) that suggest receptivity to multiple stimuli. Because Ptger3, Opn5, and Tacr3 encode G-protein coupled receptors (GPCRs), we hypothesized that elucidating the G-protein signaling in these neurons is essential to understanding the interplay of inputs in the regulation of metabolism. Here, we describe how the stimulatory Gs-alpha subunit (Gnas) in QPLOT neurons regulates metabolism in mice. We analyzed Opn5cre; Gnasfl/fl mice using indirect calorimetry at ambient temperatures of 22°C (a historical standard), 10°C (a cold challenge), and 28°C (thermoneutrality) to assess the ability of QPLOT neurons to regulate metabolism. We observed a marked decrease in nocturnal locomotion of Opn5cre; Gnasfl/fl mice at both 28°C and 22°C, but no overall differences in energy expenditure, respiratory exchange, or food and water consumption. To analyze daily rhythmic patterns of metabolism, we assessed circadian parameters including amplitude, phase, and MESOR. Loss-of-function GNAS in QPLOT neurons resulted in several subtle rhythmic changes in multiple metabolic parameters. We observed that Opn5cre; Gnasfl/fl mice show a higher rhythm-adjusted mean energy expenditure at 22°C and 10°C, and an exaggerated respiratory exchange shift with temperature. At 28°C, Opn5cre; Gnasfl/fl mice have a significant delay in the phase of energy expenditure and respiratory exchange. Rhythmic analysis also showed limited increases in rhythm-adjusted means of food and water intake at 22°C and 28°C. Together, these data advance our understanding of Gαs-signaling in preoptic QPLOT neurons in regulating daily patterns of metabolism.
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Affiliation(s)
- Kevin D Gaitonde
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Molecular & Developmental Biology Graduate Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States of America
- Medical Scientist Training Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States of America
| | - Mutahar Andrabi
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States of America
| | - Courtney A Burger
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States of America
| | - Shane P D'Souza
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Molecular & Developmental Biology Graduate Program, University of Cincinnati, College of Medicine, Cincinnati, OH, United States of America
| | - Shruti Vemaraju
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States of America
| | - Bala S C Koritala
- Division of Pediatric Otolaryngology-Head and Neck Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - David F Smith
- Division of Pediatric Otolaryngology-Head and Neck Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- The Center for Circadian Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
| | - Richard A Lang
- Division of Pediatric Ophthalmology, Abrahamson Pediatric Eye Institute, Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Science of Light Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States of America
- Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States of America
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4
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Moullé VS. Autonomic control of pancreatic beta cells: What is known on the regulation of insulin secretion and beta-cell proliferation in rodents and humans. Peptides 2022; 148:170709. [PMID: 34896576 DOI: 10.1016/j.peptides.2021.170709] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/17/2021] [Accepted: 12/07/2021] [Indexed: 11/21/2022]
Abstract
Insulin secretion and pancreatic beta-cell proliferation are tightly regulated by several signals such as hormones, nutrients, and neurotransmitters. However, the autonomic control of beta cells is not fully understood. In this review, we describe mechanisms involved in insulin secretion as well as metabolic and mitogenic actions on its target tissues. Since pancreatic islets are physically connected to the brain by nerves, parasympathetic and sympathetic neurotransmitters can directly potentiate or repress insulin secretion and beta-cell proliferation. Finally, we highlight the role of the autonomic nervous system in metabolic diseases such as diabetes and obesity.
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Yang D, Wu X, Wang W, Zhou Y, Wang Z. Ciliary Type III Adenylyl Cyclase in the VMH Is Crucial for High-Fat Diet-Induced Obesity Mediated by Autophagy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2102568. [PMID: 34783461 PMCID: PMC8787410 DOI: 10.1002/advs.202102568] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Neuronal primary cilia are crucial for body weight maintenance. Type III adenylyl cyclase (AC3) is abundantly enriched in neuronal cilia, and mice with global AC3 ablation are obese. However, whether AC3 regulates body weight through its ciliary expression and the mechanism underlying this potential regulation are not clear. In this study, humanized AC3 knock-in mice that are resistant to high-fat diet (HFD)-induced obesity are generated, and increases in the number and length of cilia in the ventromedial hypothalamus (VMH) are shown. It is demonstrated that mice with specifically knocked down ciliary AC3 expression in the VMH show pronounced HFD-induced obesity. In addition, in vitro and in vivo analyses of the VMH show that ciliary AC3 regulates autophagy by binding an autophagy-related gene, gamma-aminobutyric acid A receptor-associated protein (GABARAP). Mice with GABARAP knockdown in the VMH exhibit exacerbated HFD-induced obesity. Overall, the findings may reveal a potential mechanism by which ciliary AC3 expression regulates body weight in the mouse VMH.
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Affiliation(s)
- Dong Yang
- College of Life ScienceInstitute of Life Science and Green DevelopmentHebei UniversityBaodingHebei071002China
| | - Xiangbo Wu
- College of Life ScienceInstitute of Life Science and Green DevelopmentHebei UniversityBaodingHebei071002China
| | - Weina Wang
- College of Life ScienceInstitute of Life Science and Green DevelopmentHebei UniversityBaodingHebei071002China
| | - Yanfen Zhou
- College of Life ScienceInstitute of Life Science and Green DevelopmentHebei UniversityBaodingHebei071002China
| | - Zhenshan Wang
- College of Life ScienceInstitute of Life Science and Green DevelopmentHebei UniversityBaodingHebei071002China
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6
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Matsumura S, Ishikawa F, Sasaki T, Terkelsen MK, Ravnskjaer K, Jinno T, Tanaka J, Goto T, Inoue K. Loss of CREB Coactivator CRTC1 in SF1 Cells Leads to Hyperphagia and Obesity by High-fat Diet But Not Normal Chow Diet. Endocrinology 2021; 162:6224280. [PMID: 33846709 PMCID: PMC8682520 DOI: 10.1210/endocr/bqab076] [Citation(s) in RCA: 3] [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: 01/20/2021] [Indexed: 12/19/2022]
Abstract
Cyclic adenosine monophosphate responsive element-binding protein-1-regulated transcription coactivator-1 (CRTC1) is a cytoplasmic coactivator that translocates to the nucleus in response to cyclic adenosine monophosphate. Whole-body knockdown of Crtc1 causes obesity, resulting in increased food intake and reduced energy expenditure. CRTC1 is highly expressed in the brain; therefore, it might play an important role in energy metabolism via the neuronal pathway. However, the precise mechanism by which CRTC1 regulates energy metabolism remains unknown. Here, we showed that mice lacking CRTC1, specifically in steroidogenic factor-1 expressing cells (SF1 cells), were sensitive to high-fat diet (HFD)-induced obesity, exhibiting hyperphagia and increased body weight gain. The loss of CRTC1 in SF1 cells impaired glucose metabolism. Unlike whole-body CRTC1 knockout mice, SF1 cell-specific CRTC1 deletion did not affect body weight gain or food intake in normal chow feeding. Thus, CRTC1 in SF1 cells is required for normal appetite regulation in HFD-fed mice. CRTC1 is primarily expressed in the brain. Within the hypothalamus, which plays an important role for appetite regulation, SF1 cells are only found in ventromedial hypothalamus. RNA sequencing analysis of microdissected ventromedial hypothalamus samples revealed that the loss of CRTC1 significantly changed the expression levels of certain genes. Our results revealed the important protective role of CRTC1 in SF1 cells against dietary metabolic imbalance.
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Affiliation(s)
- Shigenobu Matsumura
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
- Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Osaka, 583-8555, Japan
- Correspondence: Shigenobu Matsumura, Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino, Osaka, 583-8555, Japan. E-mail:
| | - Fuka Ishikawa
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
| | - Tsutomu Sasaki
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Mike Krogh Terkelsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Kim Ravnskjaer
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Tomoki Jinno
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
| | - Jin Tanaka
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
| | - Tsuyoshi Goto
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
| | - Kazuo Inoue
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Kyoto, 611-0011, Japan
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7
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Kaneko K, Lin HY, Fu Y, Saha PK, De la Puente-Gomez AB, Xu Y, Ohinata K, Chen P, Morozov A, Fukuda M. Rap1 in the VMH regulates glucose homeostasis. JCI Insight 2021; 6:142545. [PMID: 33974562 PMCID: PMC8262364 DOI: 10.1172/jci.insight.142545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet–induced (HFD-induced) obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in steroidogenic factor-1–positive (SF-1–positive) neurons in the ventromedial hypothalamic nucleus (VMH) known to regulate glucose metabolism. While having no effect on body weight regardless of sex, diet, and age, Rap1 deficiency in the VMH SF1 neurons markedly lowered blood glucose and insulin levels, improved glucose and insulin tolerance, and protected mice against HFD-induced neural leptin resistance and peripheral insulin resistance at the cellular and whole-body levels. Last, acute pharmacological inhibition of brain exchange protein directly activated by cAMP 2, a direct activator of Rap1, corrected glucose imbalance in obese mouse models. Our findings uncover the primary role of VMH Rap1 in glycemic control and implicate Rap1 signaling as a potential target for therapeutic intervention in diabetes.
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Affiliation(s)
- Kentaro Kaneko
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Hsiao-Yun Lin
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yukiko Fu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Ana B De la Puente-Gomez
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Peter Chen
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, NIH, Maryland, USA.,Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, USA
| | - Makoto Fukuda
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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8
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New Insights of SF1 Neurons in Hypothalamic Regulation of Obesity and Diabetes. Int J Mol Sci 2021; 22:ijms22126186. [PMID: 34201257 PMCID: PMC8229730 DOI: 10.3390/ijms22126186] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 12/16/2022] Open
Abstract
Despite the substantial role played by the hypothalamus in the regulation of energy balance and glucose homeostasis, the exact mechanisms and neuronal circuits underlying this regulation remain poorly understood. In the last 15 years, investigations using transgenic models, optogenetic, and chemogenetic approaches have revealed that SF1 neurons in the ventromedial hypothalamus are a specific lead in the brain’s ability to sense glucose levels and conduct insulin and leptin signaling in energy expenditure and glucose homeostasis, with minor feeding control. Deletion of hormonal receptors, nutritional sensors, or synaptic receptors in SF1 neurons triggers metabolic alterations mostly appreciated under high-fat feeding, indicating that SF1 neurons are particularly important for metabolic adaptation in the early stages of obesity. Although these studies have provided exciting insight into the implications of hypothalamic SF1 neurons on whole-body energy homeostasis, new questions have arisen from these results. Particularly, the existence of neuronal sub-populations of SF1 neurons and the intricate neurocircuitry linking these neurons with other nuclei and with the periphery. In this review, we address the most relevant studies carried out in SF1 neurons to date, to provide a global view of the central role played by these neurons in the pathogenesis of obesity and diabetes.
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9
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Senn SS, Le Foll C, Whiting L, Tarasco E, Duffy S, Lutz TA, Boyle CN. Unsilencing of native LepRs in hypothalamic SF1 neurons does not rescue obese phenotype in LepR-deficient mice. Am J Physiol Regul Integr Comp Physiol 2019; 317:R451-R460. [PMID: 31314542 DOI: 10.1152/ajpregu.00111.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Leptin receptor (LepR) signaling in neurons of the ventromedial nucleus of the hypothalamus (VMH), specifically those expressing steroidogenic factor-1 (SF1), have been proposed to play a key role in controlling energy balance. By crossing LepR-silenced (LepRloxTB) mice with those expressing SF1-Cre, we unsilenced native LepR specifically in the VMH and tested whether SF1 neurons in the VMH are critical mediators of leptin's effect on energy homeostasis. LepRloxTB × SF1-Cre [knockout (KO)/Tg+] mice were metabolically phenotyped and compared with littermate controls that either expressed or were deficient in LepRs. Leptin-induced phosphorylated STAT3 was present in the VMH of KO/Tg+ mice and absent in other hypothalamic nuclei. VMH leptin signaling did not ameliorate obesity resulting from LepR deficiency in chow-fed mice. There was no change in food intake or energy expenditure when comparing complete LepR-null mice with KO/Tg+ mice, nor did KO/Tg+ mice show improved glucose tolerance. The presence of functional LepRs in the VMH mildly enhanced sensitivity to the pancreatic hormone amylin. When maintained on a high-fat diet (HFD), there was no reduction in diet-induced obesity in KO/Tg+ mice, but KO/Tg+ mice had improved glucose tolerance after 7 wk on an HFD compared with LepR-null mice. We conclude that LepR signaling in the VMH alone is not sufficient to correct metabolic dysfunction observed in LepR-null mice.
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Affiliation(s)
- Seraina S Senn
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Lynda Whiting
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Erika Tarasco
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Sonya Duffy
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.,Zurich Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Christina Neuner Boyle
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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10
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Chen M, Wilson EA, Cui Z, Sun H, Shrestha YB, Podyma B, Le CH, Naglieri B, Pacak K, Gavrilova O, Weinstein LS. G sα deficiency in the dorsomedial hypothalamus leads to obesity, hyperphagia, and reduced thermogenesis associated with impaired leptin signaling. Mol Metab 2019; 25:142-153. [PMID: 31014927 PMCID: PMC6601467 DOI: 10.1016/j.molmet.2019.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/08/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Gsα couples multiple receptors, including the melanocortin 4 receptor (MC4R), to intracellular cAMP generation. Germline inactivating Gsα mutations lead to obesity in humans and mice. Mice with brain-specific Gsα deficiency also develop obesity with reduced energy expenditure and locomotor activity, and impaired adaptive thermogenesis, but the underlying mechanisms remain unclear. METHODS We created mice (DMHGsKO) with Gsα deficiency limited to the dorsomedial hypothalamus (DMH) and examined the effects on energy balance and thermogenesis. RESULTS DMHGsKO mice developed severe, early-onset obesity associated with hyperphagia and reduced energy expenditure and locomotor activity, along with impaired brown adipose tissue thermogenesis. Studies in mice with loss of MC4R in the DMH suggest that defective DMH MC4R/Gsα signaling contributes to abnormal energy balance but not to abnormal locomotor activity or cold-induced thermogenesis. Instead, DMHGsKO mice had impaired leptin signaling along with increased expression of the leptin signaling inhibitor protein tyrosine phosphatase 1B in the DMH, which likely contributes to the observed hyperphagia and reductions in energy expenditure, locomotor activity, and cold-induced thermogenesis. CONCLUSIONS DMH Gsα signaling is critical for energy balance, thermogenesis, and leptin signaling. This study provides insight into how distinct signaling pathways can interact to regulate energy homeostasis and temperature regulation.
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Affiliation(s)
- Min Chen
- Metabolic Diseases Branch, Bethesda, MD, 20892, USA.
| | | | - Zhenzhong Cui
- Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Hui Sun
- Metabolic Diseases Branch, Bethesda, MD, 20892, USA
| | | | | | | | | | - Karel Pacak
- Section on Medical Neuroendocrinology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
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11
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Butler AA, Girardet C, Mavrikaki M, Trevaskis JL, Macarthur H, Marks DL, Farr SA. A Life without Hunger: The Ups (and Downs) to Modulating Melanocortin-3 Receptor Signaling. Front Neurosci 2017; 11:128. [PMID: 28360832 PMCID: PMC5352694 DOI: 10.3389/fnins.2017.00128] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/01/2017] [Indexed: 11/13/2022] Open
Abstract
Melanocortin neurons conserve body mass in hyper- or hypo-caloric conditions by conveying signals from nutrient sensors into areas of the brain governing appetite and metabolism. In mice, melanocortin-3 receptor (MC3R) deletion alters nutrient partitioning independently of hyperphagia, promoting accumulation of fat over muscle mass. Enhanced rhythms in insulin and insulin-responsive metabolic genes during hypocaloric feeding suggest partial insulin resistance and enhanced lipogenesis. However, exactly where and how MC3Rs affect metabolic control to alter nutrient partitioning is not known. The behavioral phenotypes exhibited by MC3R-deficient mice suggest a contextual role in appetite control. The impact of MC3R-deficiency on feeding behavior when food is freely available is minor. However, homeostatic responses to hypocaloric conditioning involving increased expression of appetite-stimulating (orexigenic) neuropeptides, binge-feeding, food anticipatory activity (FAA), entrainment to nutrient availability and enhanced feeding-related motivational responses are compromised with MC3R-deficiency. Rescuing Mc3r transcription in hypothalamic and limbic neurons improves appetitive responses during hypocaloric conditioning while having minor effects on nutrient partitioning, suggesting orexigenic functions. Rescuing hypothalamic MC3Rs also restores responses of fasting-responsive hypothalamic orexigenic neurons in hypocaloric conditions, suggesting actions that sensitize fasting-responsive neurons to signals from nutrient sensors. MC3R signaling in ventromedial hypothalamic SF1(+ve) neurons improves metabolic control, but does not restore appetitive responses or nutrient partitioning. In summary, desensitization of fasting-responsive orexigenic neurons may underlie attenuated appetitive responses of MC3R-deficient mice in hypocaloric situations. Further studies are needed to identify the specific location(s) of MC3Rs controlling appetitive responses and partitioning of nutrients between fat and lean tissues.
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Affiliation(s)
- Andrew A Butler
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Clemence Girardet
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Maria Mavrikaki
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - James L Trevaskis
- In vivo Pharmacology, Cardiovascular and Metabolic Disease, Medimmune Gaithersburg, MD, USA
| | - Heather Macarthur
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine St. Louis, MO, USA
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health and Science University Portland, OR, USA
| | - Susan A Farr
- Department of Internal Medicine, Division of Geriatrics, Saint Louis University School of MedicineSt. Louis, MO, USA; VA Medical CenterSt. Louis, MO, USA
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Chen M, Shrestha YB, Podyma B, Cui Z, Naglieri B, Sun H, Ho T, Wilson EA, Li YQ, Gavrilova O, Weinstein LS. Gsα deficiency in the dorsomedial hypothalamus underlies obesity associated with Gsα mutations. J Clin Invest 2016; 127:500-510. [PMID: 27991864 DOI: 10.1172/jci88622] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 11/10/2016] [Indexed: 11/17/2022] Open
Abstract
Gsα, encoded by Gnas, mediates hormone and neurotransmitter receptor-stimulated cAMP generation. Heterozygous Gsα-inactivating mutations lead to obesity in Albright hereditary osteodystrophy (AHO) patients, but only when the mutations occur on the maternal allele. This parent-of-origin effect is due to Gsα imprinting in the CNS, although the relevant CNS regions are unknown. We have now shown that mice with a Gnas gene deletion disrupting Gsα expression on the maternal allele, but not the paternal allele, in the dorsomedial nucleus of the hypothalamus (DMH) developed obesity and reduced energy expenditure without hyperphagia. Although maternal Gnas deletion impaired activation of brown adipose tissue (BAT) in mice, their responses to cold environment remained intact. Similar findings were observed in mice with DMH-specific deficiency of melanocortin MC4R receptors, which are known to activate Gsα. Our results show that Gsα imprinting in the DMH underlies the parent-of-origin metabolic phenotype that results from Gsα mutations and that DMH MC4R/Gsα signaling is important for regulation of energy expenditure and BAT activation, but not the metabolic response to cold.
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Yang H, Yang L. Targeting cAMP/PKA pathway for glycemic control and type 2 diabetes therapy. J Mol Endocrinol 2016; 57:R93-R108. [PMID: 27194812 DOI: 10.1530/jme-15-0316] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 05/18/2016] [Indexed: 12/11/2022]
Abstract
In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is usually elicited by binding of hormones and neurotransmitters to G protein-coupled receptors (GPCRs). cAMP exerts many of its physiological effects by activating cAMP-dependent protein kinase (PKA), which in turn phosphorylates and regulates the functions of downstream protein targets including ion channels, enzymes, and transcription factors. cAMP/PKA signaling pathway regulates glucose homeostasis at multiple levels including insulin and glucagon secretion, glucose uptake, glycogen synthesis and breakdown, gluconeogenesis, and neural control of glucose homeostasis. This review summarizes recent genetic and pharmacological studies concerning the regulation of glucose homeostasis by cAMP/PKA in pancreas, liver, skeletal muscle, adipose tissues, and brain. We also discuss the strategies for targeting cAMP/PKA pathway for research and potential therapeutic treatment of type 2 diabetes mellitus (T2D).
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Affiliation(s)
- Haihua Yang
- Division of EndocrinologyZhengzhou Children's Hospital, Zhengzhou, Henan, China
| | - Linghai Yang
- Department of PharmacologyUniversity of Washington, Seattle, Washington, USA
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