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Hwang J, Okada J, Liu L, Pessin JE, Schwartz GJ, Jo YH. Loss of the brain-liver axis prevents hepatic steatosis in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.03.565494. [PMID: 38260695 PMCID: PMC10802435 DOI: 10.1101/2023.11.03.565494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Hepatic lipid metabolism is regulated by the autonomic nervous system of the liver, with the sympathetic innervation being extensively studied, while the parasympathetic efferent innervation is less understood despite its potential importance. In this study, we investigate the consequences of disrupted brain-liver communication on hepatic lipid metabolism in mice exposed to obesogenic conditions. We found that a subset of hepatocytes and the bile duct are innervated by parasympathetic nerves originating from the dorsal motor nucleus of the vagus. The elimination of the brain-liver axis by deleting parasympathetic cholinergic neurons innervating the liver prevents hepatic steatosis and promots browning of inguinal white adipose tissue (ingWAT). The loss of the brain-liver axis also raises hepatic Cyp7b1 expression and fasting serum bile acid levels. Furthermore, knockdown of the G protein-coupled bile acid receptor 1 gene in ingWAT reverses the beneficial effects of the loss of the brain-liver axis, leading to the reappearance of hepatic steatosis in the experimental groups. However, deleting the brain-liver axis has a small but significant effect on body weight, which is accompanied by an increase in energy expenditure. Therefore, altering parasympathetic cholinergic innervation of the liver could offer a potential therapeutic approach for enhancing hepatic lipid metabolism in obesity and diabetes.
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Yang WZ, Xie H, Du X, Zhou Q, Xiao Y, Zhao Z, Jia X, Xu J, Zhang W, Cai S, Li Z, Fu X, Hua R, Cai J, Chang S, Sun J, Sun H, Xu Q, Ni X, Tu H, Zheng R, Xu X, Wang H, Fu Y, Wang L, Li X, Yang H, Yao Q, Yu T, Shen Q, Shen WL. A parabrachial-hypothalamic parallel circuit governs cold defense in mice. Nat Commun 2023; 14:4924. [PMID: 37582782 PMCID: PMC10427655 DOI: 10.1038/s41467-023-40504-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 08/01/2023] [Indexed: 08/17/2023] Open
Abstract
Thermal homeostasis is vital for mammals and is controlled by brain neurocircuits. Yet, the neural pathways responsible for cold defense regulation are still unclear. Here, we found that a pathway from the lateral parabrachial nucleus (LPB) to the dorsomedial hypothalamus (DMH), which runs parallel to the canonical LPB to preoptic area (POA) pathway, is also crucial for cold defense. Together, these pathways make an equivalent and cumulative contribution, forming a parallel circuit. Specifically, activation of the LPB → DMH pathway induced strong cold-defense responses, including increases in thermogenesis of brown adipose tissue (BAT), muscle shivering, heart rate, and locomotion. Further, we identified somatostatin neurons in the LPB that target DMH to promote BAT thermogenesis. Therefore, we reveal a parallel circuit governing cold defense in mice, which enables resilience to hypothermia and provides a scalable and robust network in heat production, reshaping our understanding of neural circuit regulation of homeostatic behaviors.
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Affiliation(s)
- Wen Z Yang
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Hengchang Xie
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaosa Du
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Qian Zhou
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan Xiao
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Zhengdong Zhao
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Xiaoning Jia
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Jianhui Xu
- Thermoregulation and Inflammation Laboratory, Chengdu Medical College, Chengdu, Sichuan, 610500, China
| | - Wen Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Shuang Cai
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, 563006, China
| | - Zhangjie Li
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Xin Fu
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Rong Hua
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, 200433, China
| | - Junhao Cai
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Shuang Chang
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Jing Sun
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Hongbin Sun
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Qingqing Xu
- Institute of life sciences, Chongqing Medical University, Chongqing, 400044, China
| | - Xinyan Ni
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Hongqing Tu
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, Health Science Center, Peking University, Beijing, 100871, China
- Neuroscience Research Institute, Peking University, Beijing, 100871, China
| | - Xiaohong Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Hong Wang
- Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - Yu Fu
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138667, Singapore
| | - Liming Wang
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518055, China
| | - Xi Li
- Institute of life sciences, Chongqing Medical University, Chongqing, 400044, China
| | - Haitao Yang
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China
| | - Qiyuan Yao
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, 200433, China
| | - Tian Yu
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, 563006, China.
| | - Qiwei Shen
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, 200433, China.
| | - Wei L Shen
- Shanghai Institute for Advanced Immunochemical Studies & School of Life Science and Technology, Shanghaitech University, Shanghai, 201210, China.
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3
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Takahashi TM, Sakurai T, Hirano A. Measuring body temperature of freely moving mice under an optogenetics-induced long-term hypothermic state. STAR Protoc 2023; 4:102321. [PMID: 37267111 DOI: 10.1016/j.xpro.2023.102321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/04/2023] [Accepted: 04/27/2023] [Indexed: 06/04/2023] Open
Abstract
We present a protocol for inducing a hibernation-like state in free-moving mice using optogenetics. We have recently developed an optogenetic technique utilizing modified Opsin4, which is activated by weak blue light, resulting in prolonged neuronal excitation. We describe a protocol that includes detailed instructions for virus injection, implantation of optic fibers and temperature transmitters, photostimulation, and real-time recording of body temperature in mice. This method is valuable for investigating the mechanisms underlying torpor and thermoregulation in mice. For complete details on the use and execution of this protocol, please refer to Takahashi et al.1.
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Affiliation(s)
- Tohru M Takahashi
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
| | - Takeshi Sakurai
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Arisa Hirano
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan; International Integrative Institute for Sleep medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
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4
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Choi Y, Min HY, Hwang J, Jo YH. Magel2 knockdown in hypothalamic POMC neurons innervating the medial amygdala reduces susceptibility to diet-induced obesity. Life Sci Alliance 2022; 5:5/11/e202201502. [PMID: 36007929 PMCID: PMC9418835 DOI: 10.26508/lsa.202201502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022] Open
Abstract
Hyperphagia and obesity profoundly affect the health of children with Prader-Willi syndrome (PWS). The Magel2 gene among the genes in the Prader-Willi syndrome deletion region is expressed in proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC). Knockout of the Magel2 gene disrupts POMC neuronal circuits and functions. Here, we report that loss of the Magel2 gene exclusively in ARCPOMC neurons innervating the medial amygdala (MeA) causes a reduction in body weight in both male and female mice fed with a high-fat diet. This anti-obesity effect is associated with an increased locomotor activity. There are no significant differences in glucose and insulin tolerance in mice without the Magel2 gene in ARCPOMC neurons innervating the MeA. Plasma estrogen levels are higher in female mutant mice than in controls. Blockade of the G protein-coupled estrogen receptor (GPER), but not estrogen receptor-α (ER-α), reduces locomotor activity in female mutant mice. Hence, our study provides evidence that knockdown of the Magel2 gene in ARCPOMC neurons innervating the MeA reduces susceptibility to diet-induced obesity with increased locomotor activity through activation of central GPER.
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Affiliation(s)
- Yuna Choi
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York City, NY, USA.,Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA
| | - Hyeon-Young Min
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York City, NY, USA.,Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA
| | - Jiyeon Hwang
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York City, NY, USA.,Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA
| | - Young-Hwan Jo
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, New York City, NY, USA .,Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA.,Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York City, NY, USA
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5
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Zhou Q, Liu C, Chen T, Liu Y, Cao R, Ni X, Yang WZ, Shen Q, Sun H, Shen WL. Cooling-activated dorsomedial hypothalamic BDNF neurons control cold defense in mice. J Neurochem 2022; 163:220-232. [PMID: 35862478 DOI: 10.1111/jnc.15666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/30/2022]
Abstract
BDNF and its expressing neurons in the brain critically control feeding and energy expenditure (EE) in both rodents and humans. However, whether BDNF neurons would function in thermoregulation during temperature challenges is unclear. Here, we show that BDNF neurons in the dorsomedial hypothalamus (DMHBDNF ) of mice are activated by afferent cooling signals. These cooling-activated BDNF neurons are mainly GABAergic. Activation of DMHBDNF neurons or the GABAergic subpopulations is sufficient to increase body temperature, EE, and physical activity. Conversely, blocking DMHBDNF neurons substantially impairs cold defense and reduces energy expenditure, physical activity, and UCP1 expression in BAT, which eventually results in bodyweight gain and glucose/insulin intolerance. Therefore, we identify a subset of DMHBDNF neurons as a novel type of cooling-activated neurons to promote cold defense. Thus, we reveal a critical role of BDNF circuitry in thermoregulation, which deepens our understanding of BDNF in controlling energy homeostasis and obesity.
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Affiliation(s)
- Qian Zhou
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Changhao Liu
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Ting Chen
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Yanyang Liu
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Ren Cao
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Xinyan Ni
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Wen Z Yang
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Qiwei Shen
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Hongbin Sun
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Wei L Shen
- School of Life Science and Technology, Shanghaitech University, Shanghai, China
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6
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Ambler M, Hitrec T, Wilson A, Cerri M, Pickering A. Neurons in the Dorsomedial Hypothalamus Promote, Prolong, and Deepen Torpor in the Mouse. J Neurosci 2022; 42:4267-4277. [PMID: 35440490 PMCID: PMC9145229 DOI: 10.1523/jneurosci.2102-21.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/15/2022] [Accepted: 02/25/2022] [Indexed: 12/30/2022] Open
Abstract
Torpor is a naturally occurring, hypometabolic, hypothermic state engaged by a wide range of animals in response to imbalance between the supply and demand for nutrients. Recent work has identified some of the key neuronal populations involved in daily torpor induction in mice, in particular, projections from the preoptic area of the hypothalamus to the dorsomedial hypothalamus (DMH). The DMH plays a role in thermoregulation, control of energy expenditure, and circadian rhythms, making it well positioned to contribute to the expression of torpor. We used activity-dependent genetic TRAPing techniques to target DMH neurons that were active during natural torpor bouts in female mice. Chemogenetic reactivation of torpor-TRAPed DMH neurons in calorie-restricted mice promoted torpor, resulting in longer and deeper torpor bouts. Chemogenetic inhibition of torpor-TRAPed DMH neurons did not block torpor entry, suggesting a modulatory role for the DMH in the control of torpor. This work adds to the evidence that the preoptic area of the hypothalamus and the DMH form part of a circuit within the mouse hypothalamus that controls entry into daily torpor.SIGNIFICANCE STATEMENT Daily heterotherms, such as mice, use torpor to cope with environments in which the supply of metabolic fuel is not sufficient for the maintenance of normothermia. Daily torpor involves reductions in body temperature, as well as active suppression of heart rate and metabolism. How the CNS controls this profound deviation from normal homeostasis is not known, but a projection from the preoptic area to the dorsomedial hypothalamus has recently been implicated. We demonstrate that the dorsomedial hypothalamus contains neurons that are active during torpor. Activity in these neurons promotes torpor entry and maintenance, but their activation alone does not appear to be sufficient for torpor entry.
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Affiliation(s)
- Michael Ambler
- Anaesthesia, Pain, & Critical Care Sciences, School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Timna Hitrec
- Anaesthesia, Pain, & Critical Care Sciences, School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Andrew Wilson
- Anaesthesia, Pain, & Critical Care Sciences, School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Matteo Cerri
- Department of Biomedical & Neuromotor Sciences, University of Bologna, Bologna, 40127, Italy
| | - Anthony Pickering
- Anaesthesia, Pain, & Critical Care Sciences, School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
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7
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2022; 6:313. [PMID: 35087956 PMCID: PMC8764563 DOI: 10.12688/wellcomeopenres.17379.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2022] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to review the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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Affiliation(s)
- Michael Ambler
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Timna Hitrec
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Anthony Pickering
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
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8
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Hyun U, Sohn JW. Autonomic control of energy balance and glucose homeostasis. Exp Mol Med 2022; 54:370-376. [PMID: 35474336 PMCID: PMC9076646 DOI: 10.1038/s12276-021-00705-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/07/2021] [Indexed: 11/21/2022] Open
Abstract
Neurons in the central nervous system (CNS) communicate with peripheral organs largely via the autonomic nervous system (ANS). Through such communications, the sympathetic and parasympathetic efferent divisions of the ANS may affect thermogenesis and blood glucose levels. In contrast, peripheral organs send feedback to the CNS via hormones and autonomic afferent nerves. These humoral and neural feedbacks, as well as neural commands from higher brain centers directly or indirectly shape the metabolic function of autonomic neurons. Notably, recent developments in mouse genetics have enabled more detailed studies of ANS neurons and circuits, which have helped elucidate autonomic control of metabolism. Here, we will summarize the functional organization of the ANS and discuss recent updates on the roles of neural and humoral factors in the regulation of energy balance and glucose homeostasis by the ANS. Cutting-edge techniques should be harnessed to unravel how metabolism is modulated by a key part of the body’s nervous system. The autonomic nervous system (ANS) regulates many involuntary physiological processes, such as heart rate, breathing, and blood pressure. Scientists now believe that the ANS is involved in regulating metabolism, but its precise roles are unclear. Jong-Woo Sohn and Uisu Hyun at the Korea Advanced Institute of Science and Technology, Daejeon, Korea, reviewed understanding of how the ANS regulates energy balance, appetite, and glucose homeostasis. Recently-developed mouse models have provided insights into how ANS neurons translate neuronal and hormonal signals into commands during feeding, sending instructions to the liver, and mediating blood glucose levels. Several hormones have been identified that may act on a specific part of the ANS to influence appetite and metabolism.
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Affiliation(s)
- Uisu Hyun
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
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9
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Daldegan-Bueno D, Favaro VM, Morais P, Sussulini A, Oliveira MGM. Effects of repeated ayahuasca administration on behaviour and c-Fos expression in male rats exposed to the open field. Behav Brain Res 2022; 427:113878. [DOI: 10.1016/j.bbr.2022.113878] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/18/2022] [Accepted: 03/30/2022] [Indexed: 02/06/2023]
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10
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2021; 6:313. [DOI: 10.12688/wellcomeopenres.17379.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2021] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to take a critical view of the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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11
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A hypothalamomedullary network for physiological responses to environmental stresses. Nat Rev Neurosci 2021; 23:35-52. [PMID: 34728833 DOI: 10.1038/s41583-021-00532-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 02/07/2023]
Abstract
Various environmental stressors, such as extreme temperatures (hot and cold), pathogens, predators and insufficient food, can threaten life. Remarkable progress has recently been made in understanding the central circuit mechanisms of physiological responses to such stressors. A hypothalamomedullary neural pathway from the dorsomedial hypothalamus (DMH) to the rostral medullary raphe region (rMR) regulates sympathetic outflows to effector organs for homeostasis. Thermal and infection stress inputs to the preoptic area dynamically alter the DMH → rMR transmission to elicit thermoregulatory, febrile and cardiovascular responses. Psychological stress signalling from a ventromedial prefrontal cortical area to the DMH drives sympathetic and behavioural responses for stress coping, representing a psychosomatic connection from the corticolimbic emotion circuit to the autonomic and somatic motor systems. Under starvation stress, medullary reticular neurons activated by hunger signalling from the hypothalamus suppress thermogenic drive from the rMR for energy saving and prime mastication to promote food intake. This Perspective presents a combined neural network for environmental stress responses, providing insights into the central circuit mechanism for the integrative regulation of systemic organs.
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12
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Snyder MM, Yue F, Zhang L, Shang R, Qiu J, Chen J, Kim KH, Peng Y, Oprescu SN, Donkin SS, Bi P, Kuang S. LETMD1 is required for mitochondrial structure and thermogenic function of brown adipocytes. FASEB J 2021; 35:e21965. [PMID: 34669999 DOI: 10.1096/fj.202100597r] [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] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 01/15/2023]
Abstract
Obesity and metabolic disorders caused by energy surplus pose an increasing concern within the global population. Brown adipose tissue (BAT) dissipates energy through mitochondrial non-shivering thermogenesis, thus representing a powerful agent against obesity. Here we explore the novel role of a mitochondrial outer membrane protein, LETM1-domain containing 1 (LETMD1), in BAT. We generated a knockout (Letmd1KO ) mouse model and analyzed BAT morphology, function and gene expression under various physiological conditions. While the Letmd1KO mice are born normally and have normal morphology and body weight, they lose multilocular brown adipocytes completely and have diminished mitochondrial abundance, DNA copy number, cristae structure, and thermogenic gene expression in the intrascapular BAT, associated with elevated reactive oxidative stress. In consequence, the Letmd1KO mice fail to maintain body temperature in response to acute cold exposure without food and become hypothermic within 4 h. Although the cold-exposed Letmd1KO mice can maintain body temperature in the presence of food, they cannot upregulate expression of uncoupling protein 1 (UCP1) and convert white to beige adipocytes, nor can they respond to adrenergic stimulation. These results demonstrate that LETMD1 is essential for mitochondrial structure and function, and thermogenesis of brown adipocytes.
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Affiliation(s)
- Madigan M Snyder
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Feng Yue
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Lijia Zhang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Renjie Shang
- Center for Molecular Medicine, University of Georgia, Athens, Georgia, USA
- Department of Genetics, University of Georgia, Athens, Georgia, USA
| | - Jiamin Qiu
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Jingjuan Chen
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Kun Ho Kim
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Ying Peng
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Stephanie N Oprescu
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Shawn S Donkin
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Pengpeng Bi
- Center for Molecular Medicine, University of Georgia, Athens, Georgia, USA
- Department of Genetics, University of Georgia, Athens, Georgia, USA
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
- Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
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13
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Neuro-immune-metabolism: The tripod system of homeostasis. Immunol Lett 2021; 240:77-97. [PMID: 34655659 DOI: 10.1016/j.imlet.2021.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 11/20/2022]
Abstract
Homeostatic regulation of cellular and molecular processes is essential for the efficient physiological functioning of body organs. It requires an intricate balance of several networks throughout the body, most notable being the nervous, immune and metabolic systems. Several studies have reported the interactions between neuro-immune, immune-metabolic and neuro-metabolic pathways. Current review aims to integrate the information and show that neuro, immune and metabolic systems form the triumvirate of homeostasis. It focuses on the cellular and molecular interactions occurring in the extremities and intestine, which are innervated by the peripheral nervous system and for the intestine in particular the enteric nervous system. While the interdependence of neuro-immune-metabolic pathways provides a fallback mechanism in case of disruption of homeostasis, in chronic pathologies of continued disequilibrium, the collapse of one system spreads to the other interacting networks as well. Current review illustrates this domino-effect using diabetes as the main example. Together, this review attempts to provide a holistic picture of the integrated network of neuro-immune-metabolism and attempts to broaden the outlook when devising a scientific study or a treatment strategy.
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14
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Polichnowski AJ, Williamson GA, Blair TE, Hoover DB. Autonomic and cholinergic mechanisms mediating cardiovascular and temperature effects of donepezil in conscious mice. Am J Physiol Regul Integr Comp Physiol 2021; 320:R871-R884. [PMID: 33851543 DOI: 10.1152/ajpregu.00360.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Donepezil is a centrally acting acetylcholinesterase (AChE) inhibitor with therapeutic potential in inflammatory diseases; however, the underlying autonomic and cholinergic mechanisms remain unclear. Here, we assessed effects of donepezil on mean arterial pressure (MAP), heart rate (HR), HR variability, and body temperature in conscious adult male C57BL/6 mice to investigate the autonomic pathways involved. Central versus peripheral cholinergic effects of donepezil were assessed using pharmacological approaches including comparison with the peripherally acting AChE inhibitor, neostigmine. Drug treatments included donepezil (2.5 or 5 mg/kg sc), neostigmine methyl sulfate (80 or 240 μg/kg ip), atropine sulfate (5 mg/kg ip), atropine methyl bromide (5 mg/kg ip), or saline. Donepezil, at 2.5 and 5 mg/kg, decreased HR by 36 ± 4% and 44 ± 3% compared with saline (n = 10, P < 0.001). Donepezil, at 2.5 and 5 mg/kg, decreased temperature by 13 ± 2% and 22 ± 2% compared with saline (n = 6, P < 0.001). Modest (P < 0.001) increases in MAP were observed with donepezil after peak bradycardia occurred. Atropine sulfate and atropine methyl bromide blocked bradycardic responses to donepezil, but only atropine sulfate attenuated hypothermia. The pressor response to donepezil was similar in mice coadministered atropine sulfate; however, coadministration of atropine methyl bromide potentiated the increase in MAP. Neostigmine did not alter HR or temperature, but did result in early increases in MAP. Despite the marked bradycardia, donepezil did not increase normalized high-frequency HR variability. We conclude that donepezil causes marked bradycardia and hypothermia in conscious mice via the activation of muscarinic receptors while concurrently increasing MAP via autonomic and cholinergic pathways that remain to be elucidated.
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Affiliation(s)
- Aaron J Polichnowski
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee.,Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
| | - Geoffrey A Williamson
- Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, Illinois
| | - Tesha E Blair
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Donald B Hoover
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee.,Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
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15
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Cerri M, Amici R. Thermoregulation and Sleep: Functional Interaction and Central Nervous Control. Compr Physiol 2021; 11:1591-1604. [PMID: 33792906 DOI: 10.1002/cphy.c140012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Each of the wake-sleep states is characterized by specific changes in autonomic activity and bodily functions. The goal of such changes is not always clear. During non-rapid eye movement (NREM) sleep, the autonomic outflow and the activity of the endocrine system, the respiratory system, the cardiovascular system, and the thermoregulatory system seem to be directed at increasing energy saving. During rapid eye movement (REM) sleep, the goal of the specific autonomic and regulatory changes is unclear, since a large instability of autonomic activity and cardiorespiratory function is observed in concomitance with thermoregulatory changes, which are apparently non-functional to thermal homeostasis. Reciprocally, the activation of thermoregulatory responses under thermal challenges interferes with sleep occurrence. Such a double-edged and reciprocal interaction between sleep and thermoregulation may be favored by the fact that the central network controlling sleep overlaps in several parts with the central network controlling thermoregulation. The understanding of the central mechanism behind the interaction between sleep and thermoregulation may help to understand the functionality of thermoregulatory sleep-related changes and, ultimately, the function(s) of sleep. © 2021 American Physiological Society. Compr Physiol 11:1591-1604, 2021.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and Neuromotor Sciences - Physiology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Roberto Amici
- Department of Biomedical and Neuromotor Sciences - Physiology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
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16
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Wu J, Liu D, Li J, Sun J, Huang Y, Zhang S, Gao S, Mei W. Central Neural Circuits Orchestrating Thermogenesis, Sleep-Wakefulness States and General Anesthesia States. Curr Neuropharmacol 2021; 20:223-253. [PMID: 33632102 PMCID: PMC9199556 DOI: 10.2174/1570159x19666210225152728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 02/01/2021] [Accepted: 02/24/2021] [Indexed: 11/22/2022] Open
Abstract
Great progress has been made in specifically identifying the central neural circuits (CNCs) of the core body temperature (Tcore), sleep-wakefulness states (SWs), and general anesthesia states (GAs), mainly utilizing optogenetic or chemogenetic manipulations. We summarize the neuronal populations and neural pathways of these three CNCs, which gives evidence for the orchestration within these three CNCs, and the integrative regulation of these three CNCs by different environmental light signals. We also outline some transient receptor potential (TRP) channels that function in the CNCs-Tcore and are modulated by some general anesthetics, which makes TRP channels possible targets for addressing the general-anesthetics-induced-hypothermia (GAIH). We suggest this review will provide new orientations for further consummating these CNCs and elucidating the central mechanisms of GAIH.
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Affiliation(s)
- Jiayi Wu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Daiqiang Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Jiayan Li
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Jia Sun
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Yujie Huang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Shuang Zhang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Shaojie Gao
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030. China
| | - Wei Mei
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Ave 1095, Wuhan 430030. China
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17
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Optogenetic stimulation of the liver-projecting melanocortinergic pathway promotes hepatic glucose production. Nat Commun 2020; 11:6295. [PMID: 33293550 PMCID: PMC7722761 DOI: 10.1038/s41467-020-20160-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 11/18/2020] [Indexed: 12/18/2022] Open
Abstract
The central melanocortin system plays a fundamental role in the control of feeding and body weight. Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC) also regulate overall glucose homeostasis via insulin-dependent and -independent pathways. Here, we report that a subset of ARC POMC neurons innervate the liver via preganglionic parasympathetic acetylcholine (ACh) neurons in the dorsal motor nucleus of the vagus (DMV). Optogenetic stimulation of this liver-projecting melanocortinergic pathway elevates blood glucose levels that is associated with increased expression of hepatic gluconeogenic enzymes in female and male mice. Pharmacological blockade and knockdown of the melanocortin-4 receptor gene in the DMV abolish this stimulation-induced effect. Activation of melanocortin-4 receptors inhibits DMV cholinergic neurons and optogenetic inhibition of liver-projecting parasympathetic cholinergic fibers increases blood glucose levels. This elevated blood glucose is not due to altered pancreatic hormone release. Interestingly, insulin-induced hypoglycemia increases ARC POMC neuron activity. Hence, this liver-projecting melanocortinergic circuit that we identified may play a critical role in the counterregulatory response to hypoglycemia. Hypothalamic melanocortin neurons regulate systemic glucose homeostasis through incompletely understood pathways. Here, the authors show that a subset of pro-opiomelanocortin neurons innervate the liver via preganglionic parasympathetic cholinergic neurons in the dorsal motor nucleus of the vagus and that stimulation of this pathway elevates blood glucose levels
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18
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Kwon E, Jo YH. Activation of the ARC POMC→MeA Projection Reduces Food Intake. Front Neural Circuits 2020; 14:595783. [PMID: 33250721 PMCID: PMC7674918 DOI: 10.3389/fncir.2020.595783] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/09/2020] [Indexed: 02/05/2023] Open
Abstract
Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC) plays an essential role in the control of food intake and energy expenditure. Melanocortin-4 receptors (MC4Rs) are expressed in key areas that are implicated in regulating energy homeostasis. Although the importance of MC4Rs in the paraventricular hypothalamus (PVH) has been well documented, the role of MC4Rs in the medial amygdala (MeA) on feeding remains controversial. In this study, we specifically examine the role of a novel ARCPOMC→MeA neural circuit in the regulation of short-term food intake. To map a local melanocortinergic neural circuit, we use monosynaptic anterograde as well as retrograde viral tracers and perform double immunohistochemistry to determine the identity of the neurons receiving synaptic input from POMC neurons in the ARC. To investigate the role of the ARCPOMC→MeA projection on feeding, we optogenetically stimulate channelrhodopsin-2 (ChR2)-expressing POMC fibers in the MeA. Anterograde viral tracing studies reveal that ARC POMC neurons send axonal projections to estrogen receptor-α (ER-α)- and MC4R-expressing neurons in the MeA. Retrograde viral tracing experiments show that the neurons projecting to the MeA is located mainly in the lateral part of the ARC. Optogenetic stimulation of the ARCPOMC→MeA pathway reduces short-term food intake. This anorectic effect is blocked by treatment with the MC4R antagonist SHU9119. In addition to the melanocortinergic local circuits within the hypothalamus, this extrahypothalamic ARCPOMC→MeA neural circuit would play a role in regulating short-term food intake.
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Affiliation(s)
- Eunjin Kwon
- The Fleischer Institute for Diabetes and Metabolism, Bronx, NY, United States
- Division of Endocrinology, Department of Medicine, Bronx, NY, United States
| | - Young-Hwan Jo
- The Fleischer Institute for Diabetes and Metabolism, Bronx, NY, United States
- Division of Endocrinology, Department of Medicine, Bronx, NY, United States
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
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19
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Ghrelin infused into the dorsomedial hypothalamus of male mice increases food intake and adiposity. Physiol Behav 2020; 220:112882. [PMID: 32205145 DOI: 10.1016/j.physbeh.2020.112882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023]
Abstract
Ghrelin is a 28 amino acid peptide hormone that targets the brain to promote feeding and adiposity. The ghrelin receptor, the GHSR1a, is expressed within most hypothalamic nuclei, including the DMH, but the role of GHSR1a in this region on energy balance is unknown. In order to investigate whether GHSR1a within the DMH modulate energy balance, we implanted osmotic minipumps filled with saline, ghrelin, or the GHSR1a antagonist JMV2959, and connected it to a cannula aimed unilaterally at the DMH of adult male C57BLJ6 mice and assessed their metabolic profile. We found that chronic infusion of ghrelin in the DMH promoted an increase in caloric intake as well as a decrease in energy expenditure. This translated to an overall increase in weight gain, primarily in the form of adipose tissue in ghrelin treated animals. Further, chronic ghrelin unilateral infusion into the DMH slowed glucose clearance. These results suggest that GHSR in the DMH significantly contribute to the metabolic effects produced by ghrelin.
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20
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Abstract
Torpor is a peculiar mammalian behaviour, characterized by the active reduction of metabolic rate, followed by a drop in body temperature. To enter torpor, the activation of all thermogenic organs that could potentially defend body temperature must be prevented. Most of these organs, such as the brown adipose tissue, are controlled by the key thermoregulatory region of the Raphe Pallidus (RPa). Currently, it is not known which brain areas mediate the entrance into torpor. To identify these areas, the expression of the early gene c-Fos at torpor onset was assessed in different brain regions in mice injected with a retrograde tracer (Cholera Toxin subunit b, CTb) into the RPa region. The results show a network of hypothalamic neurons that are specifically activated at torpor onset and a direct torpor-specific projection from the Dorsomedial Hypothalamus to the RPa that could putatively mediate the suppression of thermogenesis during torpor.
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21
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Tan CL, Knight ZA. Regulation of Body Temperature by the Nervous System. Neuron 2019; 98:31-48. [PMID: 29621489 DOI: 10.1016/j.neuron.2018.02.022] [Citation(s) in RCA: 286] [Impact Index Per Article: 57.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 01/24/2023]
Abstract
The regulation of body temperature is one of the most critical functions of the nervous system. Here we review our current understanding of thermoregulation in mammals. We outline the molecules and cells that measure body temperature in the periphery, the neural pathways that communicate this information to the brain, and the central circuits that coordinate the homeostatic response. We also discuss some of the key unresolved issues in this field, including the following: the role of temperature sensing in the brain, the molecular identity of the warm sensor, the central representation of the labeled line for cold, and the neural substrates of thermoregulatory behavior. We suggest that approaches for molecularly defined circuit analysis will provide new insight into these topics in the near future.
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Affiliation(s)
- Chan Lek Tan
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158; Kavli Center for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158.
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22
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Silvani A, Cerri M, Zoccoli G, Swoap SJ. Is Adenosine Action Common Ground for NREM Sleep, Torpor, and Other Hypometabolic States? Physiology (Bethesda) 2019; 33:182-196. [PMID: 29616880 DOI: 10.1152/physiol.00007.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review compares two states that lower energy expenditure: non-rapid eye movement (NREM) sleep and torpor. Knowledge on mechanisms common to these states, and particularly on the role of adenosine in NREM sleep, may ultimately open the possibility of inducing a synthetic torpor-like state in humans for medical applications and long-term space travel. To achieve this goal, it will be important, in perspective, to extend the study to other hypometabolic states, which, unlike torpor, can also be experienced by humans.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy
| | - Matteo Cerri
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy.,National Institute of Nuclear Physics (INFN), Section of Bologna, Bologna , Italy
| | - Giovanna Zoccoli
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy
| | - Steven J Swoap
- Department of Biology, Williams College , Williamstown, Massachusetts
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23
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Gospodarska E, Kozak LP, Jaroslawska J. Isolation and identification of endogenous RFamide-related peptides 1 and 3 in the mouse hypothalamus. J Neuroendocrinol 2019; 31:e12668. [PMID: 30521140 DOI: 10.1111/jne.12668] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/14/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022]
Abstract
Although the RFamide-related peptide (RFRP) preproprotein sequence is known in mice, until now, the molecular structure of the mature, functional peptides processed from the target precursor molecule has not been determined. In the present study, we purified endogenous RFRP1 and RFRP3 peptides from mouse hypothalamic tissue extracts using an immunoaffinity column conjugated with specific antibodies against the mouse C-terminus of RFRP-1 and RFRP-3. Employing liquid chromatography coupled with mass spectrometry, we demonstrated that RFRP1 consists of 15 amino acid residues and RFRP3 consists of 10 amino acid residues (ANKVPHSAANLPLRF-NH2 and SHFPSLPQRF-NH2, respectively). To investigate the distribution of RFRPs in the mouse central nervous system, we performed immunohistochemical staining of the brain sections collected from wild-type and Rfrp knockout animals. These data, together with gene expression in multiple tissues, provide strong confidence that RFRP-immunoreactive neuronal cells are localised in the dorsomedial hypothalamic nucleus (DMH) and between the DMH and the ventromedial hypothalamic nuclei. The identification of RFRP1 and RFRP3 peptides and immunohistochemical visualisation of targeting RFRPs neurones in the mice brain provide the basis for further investigations of the functional biology of RFRPs.
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Affiliation(s)
- Emilia Gospodarska
- Department of Biological Functions of Food, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
| | - Leslie P Kozak
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine
| | - Julia Jaroslawska
- Department of Biological Functions of Food, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
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24
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Couselo-Seijas M, López-Canoa JN, Agra-Bermejo RM, Díaz-Rodriguez E, Fernandez AL, Martinez-Cereijo JM, Durán-Muñoz D, Bravo SB, Velo A, González-Melchor L, Fernández-López XA, Martínez-Sande JL, García-Seara J, González-Juanatey JR, Rodriguez-Mañero M, Eiras S. Cholinergic activity regulates the secretome of epicardial adipose tissue: Association with atrial fibrillation. J Cell Physiol 2018; 234:10512-10522. [PMID: 30480808 DOI: 10.1002/jcp.27723] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/16/2018] [Indexed: 12/18/2022]
Abstract
Botulinum toxin injection on epicardial fat, which inhibits acetylcholine (ACh) release, reduced the presence of atrial fibrillation (AF) in patients after heart surgery. Thus, we wanted to study the profile of the released proteins of epicardial adipose tissue (EAT) under cholinergic activity (ACh treatment) and their value as AF predictors. Biopsies, explants, or primary cultures were obtained from the EAT of 85 patients that underwent open heart surgery. The quantification of muscarinic receptors (mAChR) by real-time polymerase chain reaction or western blot showed their expression in EAT. Moreover, mAChR Type 3 was upregulated after adipogenesis induction (p < 0.05). Cholinergic fibers in EAT were detected by vesicular ACh transporter levels and/or acetylcholinesterase activity. ACh treatment modified the released proteins by EAT, which were identified by nano-high-performance liquid chromatography and TripleTOF analysis. These differentially released proteins were involved in cell structure, inflammation, or detoxification. After testing the plasma levels of alpha-defensin 3 (inflammation-involved protein) of patients who underwent open heart surgery ( n = 24), we observed differential levels between the patients who developed or did not develop postsurgery AF (1.58 ± 1.61 ng/ml vs. 6.2 ± 5.6 ng/ml; p < 0.005). The cholinergic activity on EAT might suggest a new mechanism for studying the interplay among EAT, autonomic nervous system dysfunction, and AF.
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Affiliation(s)
- Marinela Couselo-Seijas
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Jose N López-Canoa
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Rosa M Agra-Bermejo
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
| | - Esther Díaz-Rodriguez
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Angel L Fernandez
- CIBERCV, Madrid, Spain.,Heart Surgery Department, University Clinical Hospital of Santiago dtye Compostela, Santiago de Compostela, Spain
| | - Jose M Martinez-Cereijo
- Heart Surgery Department, University Clinical Hospital of Santiago dtye Compostela, Santiago de Compostela, Spain
| | - Dario Durán-Muñoz
- CIBERCV, Madrid, Spain.,Heart Surgery Department, University Clinical Hospital of Santiago dtye Compostela, Santiago de Compostela, Spain
| | - Susana B Bravo
- Proteomic Unit of Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Alba Velo
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Laila González-Melchor
- Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Xesus A Fernández-López
- Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Jose L Martínez-Sande
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
| | - Javier García-Seara
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
| | - Jose R González-Juanatey
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
| | - Moises Rodriguez-Mañero
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Cardiovascular Area and Coronary Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
| | - Sonia Eiras
- Cardiology Group, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,CIBERCV, Madrid, Spain
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25
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Piñol RA, Zahler SH, Li C, Saha A, Tan BK, Škop V, Gavrilova O, Xiao C, Krashes MJ, Reitman ML. Brs3 neurons in the mouse dorsomedial hypothalamus regulate body temperature, energy expenditure, and heart rate, but not food intake. Nat Neurosci 2018; 21:1530-1540. [PMID: 30349101 PMCID: PMC6203600 DOI: 10.1038/s41593-018-0249-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 08/28/2018] [Indexed: 01/01/2023]
Abstract
Bombesin-like receptor 3 (BRS3) is an orphan G protein-coupled receptor that regulates energy homeostasis and heart rate. We report that acute activation of Brs3-expressing neurons in the dorsomedial hypothalamus (DMHBrs3) increased body temperature (Tb), brown adipose tissue temperature, energy expenditure, heart rate and blood pressure, with no effect on food intake or physical activity. Conversely, activation of Brs3 neurons in the paraventricular nucleus of the hypothalamus (PVHBrs3) had no effect on Tb or energy expenditure, but suppressed food intake. Inhibition of DMHBrs3 neurons decreased Tb and energy expenditure, suggesting a necessary role in Tb regulation. We found that the preoptic area provides major input (excitatory and inhibitory) to DMHBrs3 neurons. Optogenetic stimulation of DMHBrs3 projections to the raphe pallidus (RPa) increased Tb. Thus, DMHBrs3→RPa neurons regulate Tb, energy expenditure and heart rate, and PVHBrs3 neurons regulate food intake. Brs3 expression is a useful marker for delineating energy metabolism regulatory circuitry.
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Affiliation(s)
- Ramón A Piñol
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Sebastian H Zahler
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Chia Li
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Atreyi Saha
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Brandon K Tan
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Vojtěch Škop
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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Intracellular glycolysis in brown adipose tissue is essential for optogenetically induced nonshivering thermogenesis in mice. Sci Rep 2018; 8:6672. [PMID: 29704006 PMCID: PMC5923201 DOI: 10.1038/s41598-018-25265-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 04/18/2018] [Indexed: 12/23/2022] Open
Abstract
Release of fatty acids from lipid droplets upon activation of the sympathetic nervous system (SNS) is a key step in nonshivering thermogenesis in brown adipose tissue (BAT). However, intracellular lipolysis appears not to be critical for cold-induced thermogenesis. As activation of the SNS increases glucose uptake, we studied whether intracellular glycolysis plays a role in BAT thermogenesis. To stimulate BAT-innervating sympathetic nerves in vivo, we expressed channelrhodopsin-2 (ChR2) in catecholaminergic fibers by crossbreeding tyrosine hydroxylase-Cre mice with floxed-stop ChR2 mice. Acute optogenetic stimulation of sympathetic efferent fibers of BAT increased body temperature and lowered blood glucose levels that were completely abolished by the β-adrenergic receptor antagonist. Knockdown of the Ucp1 gene in BAT blocked the effects of optogenetic stimulation on body temperature and glucose uptake. Inhibition of glucose uptake in BAT and glycolysis abolished optogenetically induced thermogenesis. Stimulation of sympathetic nerves upregulated expression of the lactate dehydrogenase-A and -B genes in BAT. Optogenetic stimulation failed to induce thermogenesis following treatment with the LDH inhibitor. Pharmacological blockade and genetic deletion of the monocarboxylate transporter 1 completely abolished the effects of sympathetic activation. Our results suggest that intracellular glycolysis and lactate shuttle play an important role in regulating acute thermogenesis in BAT.
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Lee SJ, Sanchez-Watts G, Krieger JP, Pignalosa A, Norell PN, Cortella A, Pettersen KG, Vrdoljak D, Hayes MR, Kanoski SE, Langhans W, Watts AG. Loss of dorsomedial hypothalamic GLP-1 signaling reduces BAT thermogenesis and increases adiposity. Mol Metab 2018; 11:33-46. [PMID: 29650350 PMCID: PMC6001878 DOI: 10.1016/j.molmet.2018.03.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Objective Glucagon-like peptide-1 (GLP-1) neurons in the hindbrain densely innervate the dorsomedial hypothalamus (DMH), a nucleus strongly implicated in body weight regulation and the sympathetic control of brown adipose tissue (BAT) thermogenesis. Therefore, DMH GLP-1 receptors (GLP-1R) are well placed to regulate energy balance by controlling sympathetic outflow and BAT function. Methods We investigate this possibility in adult male rats by using direct administration of GLP-1 (0.5 ug) into the DMH, knocking down DMH GLP-1R mRNA with viral-mediated RNA interference, and by examining the neurochemical phenotype of GLP-1R expressing cells in the DMH using in situ hybridization. Results GLP-1 administered into the DMH increased BAT thermogenesis and hepatic triglyceride (TG) mobilization. On the other hand, Glp1r knockdown (KD) in the DMH increased body weight gain and adiposity, with a concomitant reduction in energy expenditure (EE), BAT temperature, and uncoupling protein 1 (UCP1) expression. Moreover, DMH Glp1r KD induced hepatic steatosis, increased plasma TG, and elevated liver specific de-novo lipogenesis, effects that collectively contributed to insulin resistance. Interestingly, DMH Glp1r KD increased neuropeptide Y (NPY) mRNA expression in the DMH. GLP-1R mRNA in the DMH, however, was found in GABAergic not NPY neurons, consistent with a GLP-1R-dependent inhibition of NPY neurons that is mediated by local GABAergic neurons. Finally, DMH Glp1r KD attenuated the anorexigenic effects of the GLP-1R agonist exendin-4, highlighting an important role of DMH GLP-1R signaling in GLP-1-based therapies. Conclusions Collectively, our data show that DMH GLP-1R signaling plays a key role for BAT thermogenesis and adiposity. DMH GLP-1R stimulation acutely increases BAT thermogenesis. DMH GLP-1R mRNA knockdown decreases EE and BAT thermogenesis. DMH GLP-1R mRNA knockdown impairs lipid and glucose metabolism. Reduced DMH GLP-1R signaling blunts the anorexigenic responses to Ex-4. DMH GLP-1R signaling indirectly regulates NPY gene expression.
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Affiliation(s)
- Shin J Lee
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland.
| | - Graciela Sanchez-Watts
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | | | - Angelica Pignalosa
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Puck N Norell
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Alyssa Cortella
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Dubravka Vrdoljak
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Matthew R Hayes
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Scott E Kanoski
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Alan G Watts
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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Conceição EPS, Madden CJ, Morrison SF. Tonic inhibition of brown adipose tissue sympathetic nerve activity via muscarinic acetylcholine receptors in the rostral raphe pallidus. J Physiol 2017; 595:7495-7508. [PMID: 29023733 DOI: 10.1113/jp275299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 10/09/2017] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS A tonically active, muscarinic cholinergic inhibition of rostral raphe pallidus (rRPa) neurons influences thermogenesis of brown adipose tissue (BAT) independent of ambient temperature conditions. The tonically active cholinergic input to rRPa originates caudal to the hypothalamus. Muscarinic acetylcholine receptor (mAChR) activation in rRPa contributes to the inhibition of BAT sympathetic nerve activity (SNA) evoked by activation of neurons in the rostral ventrolateral medulla (RVLM). The RVLM is not the sole source of the muscarinic cholinergic input to rRPa. Activation of GABA receptors in rRPa does not mediate the cholinergic inhibition of BAT SNA. ABSTRACT We sought to determine if body temperature and energy expenditure are influenced by a cholinergic input to neurons in the rostral raphe pallidus (rRPa), the site of sympathetic premotor neurons controlling thermogenesis of brown adipose tissue (BAT). Nanoinjections of the muscarinic acetylcholine receptor (mAChR) agonist, oxotremorine, or the cholinesterase inhibitor, neostigmine (NEOS), in the rRPa of anaesthetized rats decreased cold-evoked BAT sympathetic nerve activity (SNA, nadirs: -72 and -95%), BAT temperature (Tbat, -0.5 and -0.6°C), expired CO2 (Exp. CO2 , -0.3 and -0.5%) and heart rate (HR, -22 and -41 bpm). NEOS into rRPa reversed the increase in BAT SNA evoked by blockade of GABA receptors in rRPa. Nanoinjections of the mAChR antagonist, scopolamine (SCOP), in the rRPa of warm rats increased BAT SNA (peak: +1087%), Tbat (+1.8°C), Exp. CO2 (+0.7%), core temperature (Tcore, +0.5°C) and HR (+54 bpm). SCOP nanoinjections in rRPa produced similar activations of BAT during cold exposure, following a brain transection caudal to the hypothalamus, and during the blockade of glutamate receptors in rRPa. We conclude that a tonically active cholinergic input to the rRPa inhibits BAT SNA via activation of local mAChR. The inhibition of BAT SNA mediated by mAChR in rRPa does not depend on activation of GABA receptors in rRPa. The increase in BAT SNA following mAChR blockade in rRPa does not depend on the activity of neurons in the hypothalamus or on glutamate receptor activation in rRPa.
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Affiliation(s)
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, 97239, USA
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Devarakonda K, Stanley S. Investigating metabolic regulation using targeted neuromodulation. Ann N Y Acad Sci 2017; 1411:83-95. [PMID: 29106710 DOI: 10.1111/nyas.13468] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/11/2017] [Accepted: 08/18/2017] [Indexed: 01/13/2023]
Abstract
The central nervous system (CNS) plays a vital role in regulating energy balance and metabolism. Over the last 50 years, studies in animal models have allowed us to identify critical CNS regions involved in these processes and even crucial cell populations. Now, techniques for genetically and anatomically targeted manipulation of specific neural populations using light (optogenetic), ligands (chemogenetic), or magnetic fields (radiogenetic/magnetogenetic) allow detailed investigation of circuits involved in metabolic regulation. In this review, we provide a brief overview of recent studies using light- and magnetic field-regulated neural activity to investigate the neural circuits contributing to metabolic control.
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Affiliation(s)
- Kavya Devarakonda
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Sarah Stanley
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York.,Diabetes, Obesity and Metabolism Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
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Choudhary RC, Jia X. Hypothalamic or Extrahypothalamic Modulation and Targeted Temperature Management After Brain Injury. Ther Hypothermia Temp Manag 2017; 7:125-133. [PMID: 28467285 PMCID: PMC5610405 DOI: 10.1089/ther.2017.0003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Targeted temperature management (TTM) has been recognized to protect tissue function and positively influence neurological outcomes after brain injury. While shivering during hypothermia nullifies the beneficial effect of TTM, traditionally, antishivering drugs or paralyzing agents have been used to reduce the shivering. The hypothalamic area of the brain helps in controlling cerebral temperature and body temperature through interactions between different brain areas. Thus, modulation of different brain areas either pharmacologically or by electrical stimulation may contribute in TTM; although, very few studies have shown that TTM might be achieved by activation and inhibition of neurons in the hypothalamic region. Recent studies have investigated potential pharmacological methods of inducing hypothermia for TTM by aiming to maintain the TTM and reduce the shivering effect without using antiparalytic drugs. Better survival and neurological outcome after brain injury have been reported after pharmacologically induced TTM. This review discusses the mechanisms and modulation of the hypothalamus with other brain areas that are involved in inducing hypothermia through which TTM may be achieved and provides therapeutic strategies for TTM after brain injury.
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Affiliation(s)
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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Glutamatergic Preoptic Area Neurons That Express Leptin Receptors Drive Temperature-Dependent Body Weight Homeostasis. J Neurosci 2017; 36:5034-46. [PMID: 27147656 DOI: 10.1523/jneurosci.0213-16.2016] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/21/2016] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED The preoptic area (POA) regulates body temperature, but is not considered a site for body weight control. A subpopulation of POA neurons express leptin receptors (LepRb(POA) neurons) and modulate reproductive function. However, LepRb(POA) neurons project to sympathetic premotor neurons that control brown adipose tissue (BAT) thermogenesis, suggesting an additional role in energy homeostasis and body weight regulation. We determined the role of LepRb(POA) neurons in energy homeostasis using cre-dependent viral vectors to selectively activate these neurons and analyzed functional outcomes in mice. We show that LepRb(POA) neurons mediate homeostatic adaptations to ambient temperature changes, and their pharmacogenetic activation drives robust suppression of energy expenditure and food intake, which lowers body temperature and body weight. Surprisingly, our data show that hypothermia-inducing LepRb(POA) neurons are glutamatergic, while GABAergic POA neurons, originally thought to mediate warm-induced inhibition of sympathetic premotor neurons, have no effect on energy expenditure. Our data suggest a new view into the neurochemical and functional properties of BAT-related POA circuits and highlight their additional role in modulating food intake and body weight. SIGNIFICANCE STATEMENT Brown adipose tissue (BAT)-induced thermogenesis is a promising therapeutic target to treat obesity and metabolic diseases. The preoptic area (POA) controls body temperature by modulating BAT activity, but its role in body weight homeostasis has not been addressed. LepRb(POA) neurons are BAT-related neurons and we show that they are sufficient to inhibit energy expenditure. We further show that LepRb(POA) neurons modulate food intake and body weight, which is mediated by temperature-dependent homeostatic responses. We further found that LepRb(POA) neurons are stimulatory glutamatergic neurons, contrary to prevalent models, providing a new view on thermoregulatory neural circuits. In summary, our study significantly expands our current understanding of central circuits and mechanisms that modulate energy homeostasis.
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Montanari T, Pošćić N, Colitti M. Factors involved in white-to-brown adipose tissue conversion and in thermogenesis: a review. Obes Rev 2017; 18:495-513. [PMID: 28187240 DOI: 10.1111/obr.12520] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 12/21/2022]
Abstract
Obesity is the result of energy intake chronically exceeding energy expenditure. Classical treatments against obesity do not provide a satisfactory long-term outcome for the majority of patients. After the demonstration of functional brown adipose tissue in human adults, great effort is being devoted to develop therapies based on the adipose tissue itself, through the conversion of fat-accumulating white adipose tissue into energy-dissipating brown adipose tissue. Anti-obesity treatments that exploit endogenous, pharmacological and nutritional factors to drive such conversion are especially in demand. In the present review, we summarize the current knowledge about the various molecules that can be applied in promoting white-to-brown adipose tissue conversion and energy expenditure and the cellular mechanisms involved.
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Affiliation(s)
- T Montanari
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
| | - N Pošćić
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
| | - M Colitti
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
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Jeong JH, Lee DK, Jo YH. Cholinergic neurons in the dorsomedial hypothalamus regulate food intake. Mol Metab 2017; 6:306-312. [PMID: 28271037 PMCID: PMC5323886 DOI: 10.1016/j.molmet.2017.01.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 01/13/2023] Open
Abstract
Objective Central cholinergic neural circuits play a role in the regulation of feeding behavior. The dorsomedial hypothalamus (DMH) is considered the appetite-stimulating center and contains cholinergic neurons. Here, we study the role of DMH cholinergic neurons in the control of food intake. Methods To selectively stimulate DMH cholinergic neurons, we expressed stimulatory designer receptors exclusively activated by designer drugs (DREADDs) and channelrhodopsins in DMH cholinergic neurons by injection of adeno-associated virus (AAV) vectors into the DMH of choline acetyltransferase (ChAT)-IRES-Cre mice. We also generated transgenic mice expressing channelrhodopsins in cholinergic neurons with the Cre-LoxP technique. To delete the Chat gene exclusively in the DMH, we injected an AAV carrying a Cre recombinase transgene into the DMH of floxed ChAT mice. Food intake was measured with and without selective stimulation of DMH cholinergic neurons. Results Mice lacking the Chat gene in the DMH show reduced body weight as compared to control. Chemogenetic activation of DMH cholinergic neurons promotes food intake. This orexigenic effect is further supported by experiments of optogenetic stimulation of DMH cholinergic neurons. DMH cholinergic neurons innervate pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus (ARC). Treatment with acetylcholine (ACh) enhances GABAergic inhibitory transmission to ARC POMC neurons that is blocked by the muscarinic receptor antagonist. Direct activation of cholinergic fibers in the ARC readily stimulates food intake that is also abolished by the muscarinic receptor antagonist. Conclusion ACh released from DMH cholinergic neurons regulates food intake and body weight. This effect is mediated in part through regulation of ARC POMC neurons. Activation of muscarinic receptors on GABAergic axon terminals enhances inhibitory tone to ARC POMC neurons. Hence, this novel DMHACh → ARCPOMC pathway plays an important role in the control of food intake and body weight. DMH cholinergic neurons innervate ARC POMC neurons. Activation of muscarinic receptors enhances inhibitory tone to ARC POMC neurons. Stimulation of DMH cholinergic neurons promotes food intake. This orexigenic effect is abolished by the muscarinic receptor antagonist. Mice lacking the Chat gene in the DMH show reduced body weight.
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Affiliation(s)
- Jae Hoon Jeong
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, NY, USA
| | - Dong Kun Lee
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, NY, USA; Department of Physiology, College of Medicine, Gyeongsang National University, Jinju, South Korea
| | - Young-Hwan Jo
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, NY, USA; Department of Molecular Pharmacology, Albert Einstein College of Medicine, NY, USA.
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Herrera JA, Ward CS, Wehrens XH, Neul JL. Methyl-CpG binding-protein 2 function in cholinergic neurons mediates cardiac arrhythmogenesis. Hum Mol Genet 2016; 25:4983-4995. [PMID: 28159985 PMCID: PMC6078594 DOI: 10.1093/hmg/ddw326] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 01/22/2023] Open
Abstract
Sudden unexpected death occurs in one quarter of deaths in Rett Syndrome (RTT), a neurodevelopmental disorder caused by mutations in Methyl-CpG-binding protein 2 (MECP2). People with RTT show a variety of autonomic nervous system (ANS) abnormalities and mouse models show similar problems including QTc interval prolongation and hypothermia. To explore the role of cardiac problems in sudden death in RTT, we characterized cardiac rhythm in mice lacking Mecp2 function. Male and female mutant mice exhibited spontaneous cardiac rhythm abnormalities including bradycardic events, sinus pauses, atrioventricular block, premature ventricular contractions, non-sustained ventricular arrhythmias, and increased heart rate variability. Death was associated with spontaneous cardiac arrhythmias and complete conduction block. Atropine treatment reduced cardiac arrhythmias in mutant mice, implicating overactive parasympathetic tone. To explore the role of MeCP2 within the parasympathetic neurons, we selectively removed MeCP2 function from cholinergic neurons (MeCP2 ChAT KO), which recapitulated the cardiac rhythm abnormalities, hypothermia, and early death seen in RTT male mice. Conversely, restoring MeCP2 only in cholinergic neurons rescued these phenotypes. Thus, MeCP2 in cholinergic neurons is necessary and sufficient for autonomic cardiac control, thermoregulation, and survival, and targeting the overactive parasympathetic system may be a useful therapeutic strategy to prevent sudden unexpected death in RTT.
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Affiliation(s)
- José A. Herrera
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
| | - Christopher S. Ward
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
| | - Xander H.T. Wehrens
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Cardiovascular Research Institute
- Departments of Medicine
- Molecular Physiology and Biophysics
- Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey L. Neul
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA
- Jan and Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, USA
- Molecular Physiology and Biophysics
- Neuroscience
- Human and Molecular Genetics
- Pediatrics, Baylor College of Medicine, Houston, TX, USA
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Contribution of adaptive thermogenesis to the hypothalamic regulation of energy balance. Biochem J 2016; 473:4063-4082. [DOI: 10.1042/bcj20160012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 08/13/2016] [Accepted: 08/30/2016] [Indexed: 12/12/2022]
Abstract
Obesity and its related disorders are among the most pervasive diseases in contemporary societies, and there is an urgent need for new therapies and preventive approaches. Given (i) our poor social capacity to correct unhealthy habits, and (ii) our evolutionarily genetic predisposition to store excess energy as fat, the current environment of caloric surplus makes the treatment of obesity extremely difficult. During the last few decades, an increasing number of methodological approaches have increased our knowledge of the neuroanatomical basis of the control of energy balance. Compelling evidence underlines the role of the hypothalamus as a homeostatic integrator of metabolic information and its ability to adjust energy balance. A greater understanding of the neural basis of the hypothalamic regulation of energy balance might indeed pave the way for new therapeutic targets. In this regard, it has been shown that several important peripheral signals, such as leptin, thyroid hormones, oestrogens and bone morphogenetic protein 8B, converge on common energy sensors, such as AMP-activated protein kinase to modulate sympathetic tone on brown adipose tissue. This knowledge may open new ways to counteract the chronic imbalance underlying obesity. Here, we review the current state of the art on the role of hypothalamus in the regulation of energy balance with particular focus on thermogenesis.
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Perez-Lloret S, Peralta MC, Barrantes FJ. Pharmacotherapies for Parkinson's disease symptoms related to cholinergic degeneration. Expert Opin Pharmacother 2016; 17:2405-2415. [PMID: 27785919 DOI: 10.1080/14656566.2016.1254189] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Dopamine depletion is one of the most important features of Parkinson's Disease (PD). However, insufficient response to dopaminergic replacement therapy suggests the involvement of other neurotransmitter systems in the pathophysiology of PD. Cholinergic degeneration contributes to gait impairments, cognitive impairment, psychosis, and REM-sleep disturbances, among other symptoms. Areas covered: In this review, we explore the idea that enhancing cholinergic tone by pharmacological or neurosurgical procedures could be a first-line therapeutic strategy for the treatment of symptoms derived from cholinergic degeneration in PD. Expert opinion: Rivastigmine, a drug that increases cholinergic tone by inhibiting the enzyme cholinesterase, is effective for dementia, whereas the use of Donepezil is still in the realm of investigation. Interesting results suggest the efficacy of these drugs in the treatment of gait dysfunction. Evidence on the clinical effects of these drugs for psychosis and REM-sleep disturbances is still weak. Stimulation of the pedunculo-pontine tegmental nuclei (which provide cholinergic innervation to the brain stem and subcortical nuclei) has also been used with some success for the treatment of gait dysfunction. Anticholinergic drugs should be used with caution in PD, as they may aggravate cholinergic symptoms. Notwithstanding, in some patients they might help control parkinsonian motor symptoms.
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Affiliation(s)
- Santiago Perez-Lloret
- a Institute of Cardiology Research , University of Buenos Aires, National Research Council (CONICET-ININCA) , Buenos Aires , Argentina
| | - María Cecilia Peralta
- b Parkinson's Disease and Movement Disorders Clinic, Neurology Department , CEMIC University Hospital , Buenos Aires , Argentina
| | - Francisco J Barrantes
- c Laboratory of Molecular Neurobiology , Institute for Biomedical Research, UCA-CONICET, Faculty of Medical Sciences , Buenos Aires , Argentina
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Abstract
Autonomic thermoregulation is a recently acquired function, as it appears for the first time in mammals and provides the brain with the ability to control energy expenditure. The importance of such control can easily be highlighted by the ability of a heterogeneous group of mammals to actively reduce metabolic rate and enter a condition of regulated hypometabolism known as torpor. The central neural circuits of thermoregulatory cold defense have been recently unraveled and could in theory be exploited to reduce energy expenditure in species that do not normally use torpor, inducing a state called synthetic torpor. This approach may represent the first steps toward the development of a technology to induce a safe and reversible state of hypometabolism in humans, unlocking many applications ranging from new medical procedures to deep space travel.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and Neuromotor Sciences, Physiology Division, Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy;
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Jeong JH, Woo YJ, Chua S, Jo YH. Single-Cell Gene Expression Analysis of Cholinergic Neurons in the Arcuate Nucleus of the Hypothalamus. PLoS One 2016; 11:e0162839. [PMID: 27611685 PMCID: PMC5017726 DOI: 10.1371/journal.pone.0162839] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/29/2016] [Indexed: 01/18/2023] Open
Abstract
The cholinoceptive system in the hypothalamus, in particular in the arcuate nucleus (ARC), plays a role in regulating food intake. Neurons in the ARC contain multiple neuropeptides, amines, and neurotransmitters. To study molecular and neurochemical heterogeneity of ARC neurons, we combine single-cell qRT-PCR and single-cell whole transcriptome amplification methods to analyze expression patterns of our hand-picked 60 genes in individual neurons in the ARC. Immunohistochemical and single-cell qRT-PCR analyses show choline acetyltransferase (ChAT)-expressing neurons in the ARC. Gene expression patterns are remarkably distinct in each individual cholinergic neuron. Two-thirds of cholinergic neurons express tyrosine hydroxylase (Th) mRNA. A large subset of these Th-positive cholinergic neurons is GABAergic as they express the GABA synthesizing enzyme glutamate decarboxylase and vesicular GABA transporter transcripts. Some cholinergic neurons also express the vesicular glutamate transporter transcript gene. POMC and POMC-processing enzyme transcripts are found in a subpopulation of cholinergic neurons. Despite this heterogeneity, gene expression patterns in individual cholinergic cells appear to be highly regulated in a cell-specific manner. In fact, membrane receptor transcripts are clustered with their respective intracellular signaling and downstream targets. This novel population of cholinergic neurons may be part of the neural circuitries that detect homeostatic need for food and control the drive to eat.
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Affiliation(s)
- Jae Hoon Jeong
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, United States of America
| | - Young Jae Woo
- Department of Genetics, Albert Einstein College of Medicine, Bronx, United States of America
| | - Streamson Chua
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, United States of America
| | - Young-Hwan Jo
- Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, United States of America
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, United States of America
- * E-mail:
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Labbé SM, Caron A, Lanfray D, Monge-Rofarello B, Bartness TJ, Richard D. Hypothalamic control of brown adipose tissue thermogenesis. Front Syst Neurosci 2015; 9:150. [PMID: 26578907 PMCID: PMC4630288 DOI: 10.3389/fnsys.2015.00150] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022] Open
Abstract
It has long been known, in large part from animal studies, that the control of brown adipose tissue (BAT) thermogenesis is insured by the central nervous system (CNS), which integrates several stimuli in order to control BAT activation through the sympathetic nervous system (SNS). SNS-mediated BAT activity is governed by diverse neurons found in brain structures involved in homeostatic regulations and whose activity is modulated by various factors including oscillations of energy fluxes. The characterization of these neurons has always represented a challenging issue. The available literature suggests that the neuronal circuits controlling BAT thermogenesis are largely part of an autonomic circuitry involving the hypothalamus, brainstem and the SNS efferent neurons. In the present review, we recapitulate the latest progresses in regards to the hypothalamic regulation of BAT metabolism. We briefly addressed the role of the thermoregulatory pathway and its interactions with the energy balance systems in the control of thermogenesis. We also reviewed the involvement of the brain melanocortin and endocannabinoid systems as well as the emerging role of steroidogenic factor 1 (SF1) neurons in BAT thermogenesis. Finally, we examined the link existing between these systems and the homeostatic factors that modulate their activities.
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Affiliation(s)
- Sebastien M Labbé
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Medicine, Université Laval Québec, QC, Canada
| | - Alexandre Caron
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Medicine, Université Laval Québec, QC, Canada
| | - Damien Lanfray
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Medicine, Université Laval Québec, QC, Canada
| | - Boris Monge-Rofarello
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Medicine, Université Laval Québec, QC, Canada
| | - Timothy J Bartness
- Department of Biology, Center for Obesity Reversal (COR), Georgia State University Atlanta, GA, USA
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Medicine, Université Laval Québec, QC, Canada
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Abstract
The continuous rise in obesity is a major concern for future healthcare management. Many strategies to control body weight focus on a permanent modification of food intake with limited success in the long term. Metabolism or energy expenditure is the other side of the coin for the regulation of body weight, and strategies to enhance energy expenditure are a current focus for obesity treatment, especially since the (re)-discovery of the energy depleting brown adipose tissue in adult humans. Conversely, several human illnesses like neurodegenerative diseases, cancer, or autoimmune deficiency syndrome suffer from increased energy expenditure and severe weight loss. Thus, strategies to modulate energy expenditure to target weight gain or loss would improve life expectancies and quality of life in many human patients. The aim of this book chapter is to give an overview of our current understanding and recent progress in energy expenditure control with specific emphasis on central control mechanisms.
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