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Hristov M, Landzhov B, Yakimova K. Effect of leptin on nitrergic neurons in the lateral hypothalamic area and the supraoptic nucleus of rats. Biotech Histochem 2024; 99:125-133. [PMID: 38533595 DOI: 10.1080/10520295.2024.2335167] [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] [Indexed: 03/28/2024] Open
Abstract
The adipocyte-derived hormone, leptin, plays a key role in the maintenance of energy homeostasis. Leptin binds to the long form of its receptor, which is predominantly expressed in various hypothalamic regions, including the lateral hypothalamic area (LH) and supraoptic nucleus (SO). Several studies have suggested that leptin directly activates neuronal nitric oxide synthase, leading to increased nitric oxide production. We used histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) as a marker for nitric oxide synthase activity and assessed the effect of leptin on nitrergic neurons in the LH and SO of rats. We found that intraperitoneal administration of leptin led to a significant increase in the number of NADPH-d-positive neurons in the LH and SO. In addition, the intensity (optical density) of NADPH-d staining in LH and SO neurons was significantly elevated in rats that received leptin compared with saline-treated rats. These findings suggest that nitrergic neurons in the LH and SO may be implicated in mediating the central effects of leptin.
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Affiliation(s)
- Milen Hristov
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
| | - Boycho Landzhov
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
| | - Krassimira Yakimova
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
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2
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Manglani K, Anika NN, Patel D, Jhaveri S, Avanthika C, Sudan S, Alimohamed Z, Tiwari K. Correlation of Leptin in Patients With Type 2 Diabetes Mellitus. Cureus 2024; 16:e57667. [PMID: 38707092 PMCID: PMC11070180 DOI: 10.7759/cureus.57667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2024] [Indexed: 05/07/2024] Open
Abstract
The exponential increase in diabetes mellitus (DM) poses serious public health concerns. In this review, we focus on the role of leptin in type 2 DM. The peripheral actions of leptin consist of upregulating proinflammatory cytokines which play an important role in the pathogenesis of type 2 DM and insulin resistance. Moreover, leptin is known to inhibit insulin secretion and plays a significant role in insulin resistance in obesity and type 2 DM. A literature search was conducted on Medline, Cochrane, Embase, and Google Scholar for relevant articles published until December 2023. The following search strings and Medical Subject Headings (MeSH terms) were used: "Diabetes Mellitus," "Leptin," "NPY," and "Biomarker." This article aims to discuss the physiology of leptin in type 2 DM, its glucoregulatory actions, its relationship with appetite, the impact that various lifestyle modifications can have on leptin levels, and, finally, explore leptin as a potential target for various treatment strategies.
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Affiliation(s)
- Kajol Manglani
- Internal Medicine, MedStar Washington Hospital Center, Washington, USA
| | | | - Dhriti Patel
- Medicine and Surgery, B.J. Medical College and Civil Hospital, Ahmedabad, IND
| | - Sharan Jhaveri
- Medicine and Surgery, Smt. Nathiba Hargovandas Lakhmichand Municipal Medical College, Gujarat University, Ahmedabad, IND
| | - Chaithanya Avanthika
- Pediatrics, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital Center, New York, USA
- Medicine and Surgery, Karnataka Institute of Medical Sciences, Hubballi, IND
| | - Sourav Sudan
- Internal Medicine, Government Medical College, Rajouri, Rajouri, IND
| | - Zainab Alimohamed
- Division of Research & Academic Affairs, Larkin Health System, South Miami, USA
| | - Kripa Tiwari
- Internal Medicine, Maimonides Medical Center, New York, USA
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3
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Tamir-Hostovsky L, Ivanovska J, Parajón E, Patel R, Wang H, Biouss G, Ivanovski N, Belik J, Pierro A, Montandon G, Gauda EB. Maturational effect of leptin on CO 2 chemosensitivity in newborn rats. Pediatr Res 2023; 94:971-978. [PMID: 37185965 DOI: 10.1038/s41390-023-02604-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 03/28/2023] [Accepted: 04/01/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Leptin augments central CO2 chemosensitivity and stabilizes breathing in adults. Premature infants have unstable breathing and low leptin levels. Leptin receptors are on CO2 sensitive neurons in the Nucleus Tractus Solitarius (NTS) and locus coeruleus (LC). We hypothesized that exogenous leptin improves hypercapnic respiratory response in newborn rats by improving central CO2 chemosensitivity. METHODS In rats at postnatal day (p)4 and p21, hyperoxic and hypercapnic ventilatory responses, and pSTAT and SOCS3 protein expression in the hypothalamus, NTS and LC were measured before and after treatment with exogenous leptin (6 µg/g). RESULTS Exogenous leptin increased the hypercapnic response in p21 but not in p4 rats (P ≤ 0.001). At p4, leptin increased pSTAT expression only in the LC, and SOCS3 expression in the NTS and LC; while at p21 pSTAT and SOCS3 levels were higher in the hypothalamus, NTS, and LC (P ≤ 0.05). CONCLUSIONS We describe the developmental profile of the effect of exogenous leptin on CO2 chemosensitivity. Exogenous leptin does not augment central CO2 sensitivity during the first week of life in newborn rats. The translational implication of these findings is that low plasma leptin levels in premature infants may not be contributing to respiratory instability. IMPACT Exogenous leptin does not augment CO2 sensitivity during the first week of life in newborn rats, similar to the developmental period when feeding behavior is resistant to leptin. Exogenous leptin increases CO2 chemosensitivity in newborn rats after the 3rd week of life and upregulates the expression of pSTAT and SOC3 in the hypothalamus, NTS and LC. Low plasma leptin levels in premature infants are unlikely contributors to respiratory instability via decreased CO2 sensitivity in premature infants. Thus, it is highly unlikely that exogenous leptin would alter this response.
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Affiliation(s)
- Liran Tamir-Hostovsky
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Julijana Ivanovska
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Eleana Parajón
- Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rachana Patel
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Huanhuan Wang
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - George Biouss
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Bouâouda H, Jha PK. Orexin and MCH neurons: regulators of sleep and metabolism. Front Neurosci 2023; 17:1230428. [PMID: 37674517 PMCID: PMC10478345 DOI: 10.3389/fnins.2023.1230428] [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: 05/28/2023] [Accepted: 08/07/2023] [Indexed: 09/08/2023] Open
Abstract
Sleep-wake and fasting-feeding are tightly coupled behavioral states that require coordination between several brain regions. The mammalian lateral hypothalamus (LH) is a functionally and anatomically complex brain region harboring heterogeneous cell populations that regulate sleep, feeding, and energy metabolism. Significant attempts were made to understand the cellular and circuit bases of LH actions. Rapid advancements in genetic and electrophysiological manipulation help to understand the role of discrete LH cell populations. The opposing action of LH orexin/hypocretin and melanin-concentrating hormone (MCH) neurons on metabolic sensing and sleep-wake regulation make them the candidate to explore in detail. This review surveys the molecular, genetic, and neuronal components of orexin and MCH signaling in the regulation of sleep and metabolism.
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Affiliation(s)
- Hanan Bouâouda
- Pharmacology Institute, Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Pawan Kumar Jha
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Petzold A, van den Munkhof HE, Figge-Schlensok R, Korotkova T. Complementary lateral hypothalamic populations resist hunger pressure to balance nutritional and social needs. Cell Metab 2023; 35:456-471.e6. [PMID: 36827985 PMCID: PMC10028225 DOI: 10.1016/j.cmet.2023.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 05/03/2022] [Accepted: 02/08/2023] [Indexed: 02/25/2023]
Abstract
Animals continuously weigh hunger and thirst against competing needs, such as social contact and mating, according to state and opportunity. Yet neuronal mechanisms of sensing and ranking nutritional needs remain poorly understood. Here, combining calcium imaging in freely behaving mice, optogenetics, and chemogenetics, we show that two neuronal populations of the lateral hypothalamus (LH) guide increasingly hungry animals through behavioral choices between nutritional and social rewards. While increased food consumption was marked by increasing inhibition of a leptin receptor-expressing (LepRLH) subpopulation at a fast timescale, LepRLH neurons limited feeding or drinking and promoted social interaction despite hunger or thirst. Conversely, neurotensin-expressing LH neurons preferentially encoded water despite hunger pressure and promoted water seeking, while relegating social needs. Thus, hunger and thirst gate both LH populations in a complementary manner to enable the flexible fulfillment of multiple essential needs.
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Affiliation(s)
- Anne Petzold
- Institute for Systems Physiology, Faculty of Medicine, University of Cologne and University Clinic Cologne, Cologne 50931, Germany; Max Planck Institute for Metabolism Research, Cologne 50931, Germany
| | - Hanna Elin van den Munkhof
- Institute for Systems Physiology, Faculty of Medicine, University of Cologne and University Clinic Cologne, Cologne 50931, Germany; Max Planck Institute for Metabolism Research, Cologne 50931, Germany
| | - Rebecca Figge-Schlensok
- Institute for Systems Physiology, Faculty of Medicine, University of Cologne and University Clinic Cologne, Cologne 50931, Germany; Max Planck Institute for Metabolism Research, Cologne 50931, Germany
| | - Tatiana Korotkova
- Institute for Systems Physiology, Faculty of Medicine, University of Cologne and University Clinic Cologne, Cologne 50931, Germany; Max Planck Institute for Metabolism Research, Cologne 50931, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany.
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Diaz C, de la Torre MM, Rubenstein JLR, Puelles L. Dorsoventral Arrangement of Lateral Hypothalamus Populations in the Mouse Hypothalamus: a Prosomeric Genoarchitectonic Analysis. Mol Neurobiol 2023; 60:687-731. [PMID: 36357614 PMCID: PMC9849321 DOI: 10.1007/s12035-022-03043-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/16/2022] [Indexed: 11/12/2022]
Abstract
The lateral hypothalamus (LH) has a heterogeneous cytoarchitectonic organization that has not been elucidated in detail. In this work, we analyzed within the framework of the prosomeric model the differential expression pattern of 59 molecular markers along the ventrodorsal dimension of the medial forebrain bundle in the mouse, considering basal and alar plate subregions of the LH. We found five basal (LH1-LH5) and four alar (LH6-LH9) molecularly distinct sectors of the LH with neuronal cell groups that correlate in topography with previously postulated alar and basal hypothalamic progenitor domains. Most peptidergic populations were restricted to one of these LH sectors though some may have dispersed into a neighboring sector. For instance, histaminergic Hdc-positive neurons were mostly contained within the basal LH3, Nts (neurotensin)- and Tac2 (tachykinin 2)-expressing cells lie strictly within LH4, Hcrt (hypocretin/orexin)-positive and Pmch (pro-melanin-concentrating hormone)-positive neurons appeared within separate LH5 subdivisions, Pnoc (prepronociceptin)-expressing cells were mainly restricted to LH6, and Sst (somatostatin)-positive cells were identified within the LH7 sector. The alar LH9 sector, a component of the Foxg1-positive telencephalo-opto-hypothalamic border region, selectively contained Satb2-expressing cells. Published studies of rodent LH subdivisions have not described the observed pattern. Our genoarchitectonic map should aid in systematic approaches to elucidate LH connectivity and function.
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Affiliation(s)
- Carmen Diaz
- Department of Medical Sciences, School of Medicine and Institute for Research in Neurological Disabilities, University of Castilla-La Mancha, 02006 Albacete, Spain
| | - Margaret Martinez de la Torre
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, 30100 Murcia, Spain
| | - John L. R. Rubenstein
- Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, UCSF Medical School, San Francisco, California USA
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, 30100 Murcia, Spain
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Hypothalamic TTF-1 orchestrates the sensitivity of leptin. Mol Metab 2022; 66:101636. [PMID: 36375792 PMCID: PMC9700031 DOI: 10.1016/j.molmet.2022.101636] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Thyroid transcription factor-1 (TTF-1), a homeodomain-containing transcription factor, is predominantly expressed in discrete areas of the hypothalamus, which acts as the central unit for the regulation of whole-body energy homeostasis. Current study designed to identify the roles of TTF-1 on the responsiveness of the hypothalamic circuit activity to circulating leptin and the development of obesity linked to the insensitivity of leptin. METHODS We generated conditional knock-out mice by crossing TTF-1flox/flox mice with leptin receptor (ObRb)Cre or proopiomelanocortin (POMC)Cre transgenic mice to interrogate the contributions of TTF-1 in leptin signaling and activity. Changes of food intake, body weight and energy expenditure were evaluated in standard or high fat diet-treated transgenic mice by using an indirect calorimetry instrument. Molecular mechanism was elucidated with immunohistochemistry, immunoblotting, quantitative PCR, and promoter assays. RESULTS The selective deletion of TTF-1 gene expression in cells expressing the ObRb or POMC enhanced the anorexigenic effects of leptin as well as the leptin-induced phosphorylation of STAT3. We further determined that TTF-1 inhibited the transcriptional activity of the ObRb gene. In line with these findings, the selective deletion of the TTF-1 gene in ObRb-positive cells led to protective effects against diet-induced obesity via the amelioration of leptin resistance. CONCLUSIONS Collectively, these results suggest that hypothalamic TTF-1 participates in the development of obesity as a molecular component involved in the regulation of cellular leptin signaling and activity. Thus, TTF-1 may represent a therapeutic target for the treatment, prevention, and control of obesity.
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Molecular profile and response to energy deficit of leptin-receptor neurons in the lateral hypothalamus. Sci Rep 2022; 12:13374. [PMID: 35927440 PMCID: PMC9352899 DOI: 10.1038/s41598-022-16492-w] [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: 04/14/2022] [Accepted: 07/11/2022] [Indexed: 11/12/2022] Open
Abstract
Leptin exerts its effects on energy balance by inhibiting food intake and increasing energy expenditure via leptin receptors in the hypothalamus. While LepR neurons in the arcuate nucleus of the hypothalamus, the primary target of leptin, have been extensively studied, LepR neurons in other hypothalamic nuclei remain understudied. LepR neurons in the lateral hypothalamus contribute to leptin's effects on food intake and reward, but due to the low abundance of this population it has been difficult to study their molecular profile and responses to energy deficit. We here explore the transcriptome of LepR neurons in the LH and their response to energy deficit. Male LepR-Cre mice were injected in the LH with an AAV carrying Cre-dependent L10:GFP. Few weeks later the hypothalami from fed and food-restricted (24-h) mice were dissected and the TRAP protocol was performed, for the isolation of translating mRNAs from LepR cells in the LH, followed by RNA sequencing. After mapping and normalization, differential expression analysis was performed with DESeq2. We confirm that the isolated mRNA is enriched in LepR transcripts and other known neuropeptide markers of LepRLH neurons, of which we investigate the localization patterns in the LH. We identified novel markers of LepRLH neurons with association to energy balance and metabolic disease, such as Acvr1c, Npy1r, Itgb1, and genes that are differentially regulated by food deprivation, such as Fam46a and Rrad. Our dataset provides a reliable and extensive resource of the molecular makeup of LH LepR neurons and their response to food deprivation.
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Kurt G, Kodur N, Quiles CR, Reynolds C, Eagle A, Mayer T, Brown J, Makela A, Bugescu R, Seo HD, Carroll QE, Daniels D, Robison AJ, Mazei-Robison M, Leinninger G. Time to drink: Activating lateral hypothalamic area neurotensin neurons promotes intake of fluid over food in a time-dependent manner. Physiol Behav 2022; 247:113707. [PMID: 35063424 PMCID: PMC8844224 DOI: 10.1016/j.physbeh.2022.113707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/24/2021] [Accepted: 01/16/2022] [Indexed: 10/19/2022]
Abstract
The lateral hypothalamic area (LHA) is essential for ingestive behavior but has primarily been studied in modulating feeding, with comparatively scant attention on drinking. This is partly because most LHA neurons simultaneously promote feeding and drinking, suggesting that ingestive behaviors track together. A notable exception are LHA neurons expressing neurotensin (LHANts neurons): activating these neurons promotes water intake but modestly restrains feeding. Here we investigated the connectivity of LHANts neurons, their necessity and sufficiency for drinking and feeding, and how timing and resource availability influence their modulation of these behaviors. LHANts neurons project broadly throughout the brain, including to the lateral preoptic area (LPO), a brain region implicated in modulating drinking behavior. LHANts neurons also receive inputs from brain regions implicated in sensing hydration and energy status. While activation of LHANts neurons is not required to maintain homeostatic water or food intake, it selectively promotes drinking during the light cycle, when ingestive drive is low. Activating LHANts neurons during this period also increases willingness to work for water or palatable fluids, regardless of their caloric content. By contrast, LHANts neuronal activation during the dark cycle does not promote drinking, but suppresses feeding during this time. Finally, we demonstrate that the activation of the LHANts → LPO projection is sufficient to mediate drinking behavior, but does not suppress feeding as observed after generally activating all LHANts neurons. Overall, our work suggests how and when LHANts neurons oppositely modulate ingestive behaviors.
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Key Words
- ARC, Arcuate nucleus
- CEA, Central amygdala
- CNO, Clozapine N-Oxide
- CPP, Conditioned place preference
- DR, Dorsal raphe
- DREADD
- DREADD, Designer receptor exclusively activated by designer drugs
- FR-1, Fixed ratio-1
- LHA
- LHA(Nts), Lateral hypothalamic area neuotensin-expressing
- LHA, Lateral hypothalamic area
- LPO, Lateral preoptic area
- LT, Lateral terminalis
- LepRb, Long form of the leptin receptor
- MnPO, Median preoptic area
- ModRabies, Genetically modified rabies virus, EnvA-∆G-Rabies-mCherry
- NTS, Nucleus of solitary tract
- Nts, Neurotensin
- NtsR1, Neurotensin receptor-1
- NtsR2, Neurotensin receptor-2
- OVLT, Organum vasculosum lamina terminalis
- PAG, Periaqueductal gray
- PB, Parabrachial area
- PR, Progressive ratio
- PVH, Paraventricular nucleus of hypothalamus
- SFO, Subfornical organ
- SNc, Substantia nigra compacta
- SO, Supraoptic nucleus
- TVA, avian viral receptor protein
- VEH, Vehicle
- VTA, Ventral tegmental area
- WT, Wild type
- Water
- aCSF, Artificial cerebrospinal fluid
- body weight
- feeding
- homeostasis
- lHb, Lateral habenula
- lateral preoptic area (LPO)
- neurotensin receptor
- reward
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Affiliation(s)
- Gizem Kurt
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Nandan Kodur
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Chelsea Reynolds
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Andrew Eagle
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Tom Mayer
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Juliette Brown
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Anna Makela
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Harim Delgado Seo
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Quinn E Carroll
- Department of Psychology and the Center for Ingestive Behavior Research, University at Buffalo, the State University of New York, Buffalo, NY 14226, USA
| | - Derek Daniels
- Department of Psychology and the Center for Ingestive Behavior Research, University at Buffalo, the State University of New York, Buffalo, NY 14226, USA
| | - A J Robison
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Gina Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
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Watts AG, Kanoski SE, Sanchez-Watts G, Langhans W. The physiological control of eating: signals, neurons, and networks. Physiol Rev 2022; 102:689-813. [PMID: 34486393 PMCID: PMC8759974 DOI: 10.1152/physrev.00028.2020] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/30/2021] [Indexed: 02/07/2023] Open
Abstract
During the past 30 yr, investigating the physiology of eating behaviors has generated a truly vast literature. This is fueled in part by a dramatic increase in obesity and its comorbidities that has coincided with an ever increasing sophistication of genetically based manipulations. These techniques have produced results with a remarkable degree of cell specificity, particularly at the cell signaling level, and have played a lead role in advancing the field. However, putting these findings into a brain-wide context that connects physiological signals and neurons to behavior and somatic physiology requires a thorough consideration of neuronal connections: a field that has also seen an extraordinary technological revolution. Our goal is to present a comprehensive and balanced assessment of how physiological signals associated with energy homeostasis interact at many brain levels to control eating behaviors. A major theme is that these signals engage sets of interacting neural networks throughout the brain that are defined by specific neural connections. We begin by discussing some fundamental concepts, including ones that still engender vigorous debate, that provide the necessary frameworks for understanding how the brain controls meal initiation and termination. These include key word definitions, ATP availability as the pivotal regulated variable in energy homeostasis, neuropeptide signaling, homeostatic and hedonic eating, and meal structure. Within this context, we discuss network models of how key regions in the endbrain (or telencephalon), hypothalamus, hindbrain, medulla, vagus nerve, and spinal cord work together with the gastrointestinal tract to enable the complex motor events that permit animals to eat in diverse situations.
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Affiliation(s)
- Alan G Watts
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Scott E Kanoski
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Graciela Sanchez-Watts
- The Department of Biological Sciences, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule-Zürich, Schwerzenbach, Switzerland
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Yu M, Han S, Wang M, Han L, Huang Y, Bo P, Fang P, Zhang Z. Baicalin protects against insulin resistance and metabolic dysfunction through activation of GALR2/GLUT4 signaling. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 95:153869. [PMID: 34923235 DOI: 10.1016/j.phymed.2021.153869] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 11/14/2021] [Accepted: 11/27/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Type 2 diabetes mellitus is a complex metabolic disorder associated with obesity, glucose intolerance and insulin resistance. Activation of GALR2 has been proposed as a therapeutic target for the treatment of insulin resistance. The previous studies showed that baicalin could mitigate insulin resistance, but the detailed mechanism of baicalin on insulin resistance has not been fully explored yet. PURPOSE In the present study, we evaluated whether baicalin mitigated insulin resistance via activation of GALR2 signaling pathway. STUDY DESIGN/METHODS Baicalin (25 mg/kg/d and 50 mg/kg/d) and/or GALR2 antagonist M871 (10 mg/kg/d) were injected individually or in combinations into obese mice once a day for three weeks, and normal and GALR2 knockdown myotubes were treated with baicalin (100 μM and 400 μM) or metformin (4 mM) in the absence or presence of M871 (800 nM) for 12 h, respectively. The molecular mechanism was explored in skeletal muscle and L6 myotubes. RESULTS The present findings showed that baicalin mitigated hyperglycemia and insulin resistance and elevated the levels of PGC-1α, GLUT4, p-p38MAPK, p-AKT and p-AS160 in skeletal muscle of obese mice. Strikingly, the baicalin-induced beneficial effects were abolished by GALR2 antagonist M871 in obese mice. In vitro, baicalin dramatically augmented glucose consumption and the activity of PGC1α-GLUT4 axis in myotubes through activation of p38MAPK and AKT pathways. Moreover, baicalin-induced elevations in glucose consumption related genes were abolished by GALR2 antagonist M871 or silencing of GALR2 in myotubes. CONCLUSIONS The present study for the first time demonstrated that baicalin protected against insulin resistance and metabolic dysfunction mainly through activation of GALR2-GLUT4 signal pathway. Our findings identified that activation of GALR2-GLUT4 signal pathway by baicalin could be a new therapeutic approach to treat insulin resistance and T2DM in clinic.
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Affiliation(s)
- Mei Yu
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Shiyu Han
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Mengyuan Wang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Long Han
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yujie Huang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Penghua Fang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China; Department of Physiology, Hanlin College, Nanjing University of Chinese Medicine, Taizhou 225300, China.
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China.
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12
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Owens-French J, Li SB, Francois M, Leigh Townsend R, Daniel M, Soulier H, Turner A, de Lecea L, Münzberg H, Morrison C, Qualls-Creekmore E. Lateral hypothalamic galanin neurons are activated by stress and blunt anxiety-like behavior in mice. Behav Brain Res 2022; 423:113773. [PMID: 35101456 PMCID: PMC8901126 DOI: 10.1016/j.bbr.2022.113773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/07/2022] [Accepted: 01/23/2022] [Indexed: 12/29/2022]
Abstract
Despite the prevalence of anxiety disorders, the molecular identity of neural circuits underlying anxiety remains unclear. The lateral hypothalamus (LH) is one brain region implicated in the regulation of anxiety, and our recent data found that chemogenetic activation of LH galanin neurons attenuated the stress response to a novel environment as measured by the marble burying test. Thus, we hypothesize that LH galanin neurons may contribute to anxiety-related behavior. We used chemogenetics and fiber photometry to test the ability of LH galanin neurons to influence anxiety and stress-related behavior. Chemogenetic activation of LH galanin neurons significantly decreased anxiety-like behavior in the elevated plus maze, open field test, and light dark test. However, LH galanin activation did not alter restraint stress induced HPA activation or freezing behavior in the fear conditioning paradigm. In vivo calcium monitoring by fiber photometry indicated that LH galanin neurons were activated by anxiogenic and/or stressful stimuli including tail suspension, novel mouse interaction, and predator odor. Further, in a fear conditioning task, calcium transients strongly increased during foot shock, but were not affected by the unconditioned stimulus tone. These data indicate that LH galanin neurons both respond to and modulate anxiety, with no influence on stress induced HPA activation or fear behaviors. Further investigation of LH galanin circuitry and functional mediators of behavioral output may offer a more refined pharmacological target as an alternative to first-line broad pharmacotherapies such as benzodiazepines.
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Al-Massadi O, Dieguez C, Schneeberger M, López M, Schwaninger M, Prevot V, Nogueiras R. Multifaceted actions of melanin-concentrating hormone on mammalian energy homeostasis. Nat Rev Endocrinol 2021; 17:745-755. [PMID: 34608277 DOI: 10.1038/s41574-021-00559-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 12/12/2022]
Abstract
Melanin-concentrating hormone (MCH) is a small cyclic peptide expressed in all mammals, mainly in the hypothalamus. MCH acts as a robust integrator of several physiological functions and has crucial roles in the regulation of sleep-wake rhythms, feeding behaviour and metabolism. MCH signalling has a very broad endocrine context and is involved in physiological functions and emotional states associated with metabolism, such as reproduction, anxiety, depression, sleep and circadian rhythms. MCH mediates its functions through two receptors (MCHR1 and MCHR2), of which only MCHR1 is common to all mammals. Owing to the wide variety of MCH downstream signalling pathways, MCHR1 agonists and antagonists have great potential as tools for the directed management of energy balance disorders and associated metabolic complications, and translational strategies using these compounds hold promise for the development of novel treatments for obesity. This Review provides an overview of the numerous roles of MCH in energy and glucose homeostasis, as well as in regulation of the mesolimbic dopaminergic circuits that encode the hedonic component of food intake.
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Affiliation(s)
- Omar Al-Massadi
- Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Santiago de Compostela, Spain.
- CIBER Fisiopatologia de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain.
| | - Carlos Dieguez
- CIBER Fisiopatologia de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Marc Schneeberger
- Laboratory of Molecular Genetics, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Miguel López
- CIBER Fisiopatologia de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Vincent Prevot
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Laboratory of Development and Plasticity of the Neuroendocrine Brain, UMR-S1172, EGID, Lille, France
| | - Ruben Nogueiras
- CIBER Fisiopatologia de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain.
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain.
- Galician Agency of Innovation (GAIN), Xunta de Galicia, Santiago de Compostela, Spain.
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Fang P, She Y, Zhao J, Yan J, Yu X, Jin Y, Wei Q, Zhang Z, Shang W. Emerging roles of kisspeptin/galanin in age-related metabolic disease. Mech Ageing Dev 2021; 199:111571. [PMID: 34517021 DOI: 10.1016/j.mad.2021.111571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/08/2021] [Accepted: 09/07/2021] [Indexed: 12/11/2022]
Abstract
Age is a major risk factor for developing metabolic diseases such as obesity and diabetes. There is an unprecedented rise in obesity and type 2 diabetes in recent decades. A convincing majority of brain-gut peptides are associated with a higher risk to develop metabolic disorders, and may contribute to the pathophysiology of age-related metabolic diseases. Accumulating basic studies revealed an intriguing role of kisspeptin and galanin involved in the amelioration of insulin resistance in different ways. In patients suffered from obesity and diabetes a significant, sex-related changes in the plasma kisspeptin and galanin levels occurred. Kisspeptin is anorexigenic to prevent obesity, its level is negatively correlative with obesity and insulin resistance. While galanin is appetitive to stimulate food intake and body weight, its level is positively correlative with obesity, HOMA-IR and glucose/triglyceride concentration. In turn, kisspeptin and galanin also distinctly increase glucose uptake and utilization as well as energy expenditure. This article reviews recent evidence dealing with the role of kisspeptin and galanin in the pathophysiology of age-related metabolic diseases. It should be therefore taken into account that the targeted modulation of those peptidergic signaling may be potentially helpful in the future treatment of age-related metabolic diseases.
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Affiliation(s)
- Penghua Fang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou, 225300, China.
| | - Yuqing She
- Department of Endocrinology, Pukou Branch of Jiangsu People's Hospital, Nanjing, 210023, China
| | - Juan Zhao
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jing Yan
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xizhong Yu
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yu Jin
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Qingbo Wei
- Key Laboratory of Acupuncture and Medicine Research of Minister of Education, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, 225001, China.
| | - Wenbin Shang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
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15
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Ramirez-Virella J, Leinninger GM. The Role of Central Neurotensin in Regulating Feeding and Body Weight. Endocrinology 2021; 162:6144574. [PMID: 33599716 PMCID: PMC7951050 DOI: 10.1210/endocr/bqab038] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Indexed: 12/16/2022]
Abstract
The small peptide neurotensin (Nts) is implicated in myriad processes including analgesia, thermoregulation, reward, arousal, blood pressure, and modulation of feeding and body weight. Alterations in Nts have recently been described in individuals with obesity or eating disorders, suggesting that disrupted Nts signaling may contribute to body weight disturbance. Curiously, Nts mediates seemingly opposing regulation of body weight via different tissues. Peripherally acting Nts promotes fat absorption and weight gain, whereas central Nts signaling suppresses feeding and weight gain. Thus, because Nts is pleiotropic, a location-based approach must be used to understand its contributions to disordered body weight and whether the Nts system might be leveraged to improve metabolic health. Here we review the role of Nts signaling in the brain to understand the sites, receptors, and mechanisms by which Nts can promote behaviors that modify body weight. New techniques permitting site-specific modulation of Nts and Nts receptor-expressing cells suggest that, even in the brain, not all Nts circuitry exerts the same function. Intriguingly, there may be dedicated brain regions and circuits via which Nts specifically suppresses feeding behavior and weight gain vs other Nts-attributed physiology. Defining the central mechanisms by which Nts signaling modifies body weight may suggest strategies to correct disrupted energy balance, as needed to address overweight, obesity, and eating disorders.
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Affiliation(s)
- Jariel Ramirez-Virella
- Neuroscience Program, Michigan State University, East Lansing, Michigan, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Gina M Leinninger
- Neuroscience Program, Michigan State University, East Lansing, Michigan, USA
- Department of Physiology, Michigan State University, East Lansing, Michigan, USA
- Correspondence: Gina M. Leinninger, PhD, Department of Physiology, Michigan State University, 5400 ISTB, 766 Service Rd, East Lansing, MI 48824, USA.
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16
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Neuropeptidergic Control of Feeding: Focus on the Galanin Family of Peptides. Int J Mol Sci 2021; 22:ijms22052544. [PMID: 33802616 PMCID: PMC7961366 DOI: 10.3390/ijms22052544] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/24/2021] [Accepted: 02/27/2021] [Indexed: 12/16/2022] Open
Abstract
Obesity/overweight are important health problems due to metabolic complications. Dysregulation of peptides exerting orexigenic/anorexigenic effects must be investigated in-depth to understand the mechanisms involved in feeding behaviour. One of the most important and studied orexigenic peptides is galanin (GAL). The aim of this review is to update the mechanisms of action and physiological roles played by the GAL family of peptides (GAL, GAL-like peptide, GAL message-associated peptide, alarin) in the control of food intake and to review the involvement of these peptides in metabolic diseases and food intake disorders in experimental animal models and humans. The interaction between GAL and NPY in feeding and energy metabolism, the relationships between GAL and other substances involved in food intake mechanisms, the potential pharmacological strategies to treat food intake disorders and obesity and the possible clinical applications will be mentioned and discussed. Some research lines are suggested to be developed in the future, such as studies focused on GAL receptor/neuropeptide Y Y1 receptor interactions in hypothalamic and extra-hypothalamic nuclei and sexual differences regarding the expression of GAL in feeding behaviour. It is also important to study the possible GAL resistance in obese individuals to better understand the molecular mechanisms by which GAL regulates insulin/glucose metabolism. GAL does not exert a pivotal role in weight regulation and food intake, but this role is crucial in fat intake and also exerts an important action by regulating the activity of other key compounds under conditions of stress/altered diet.
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Fang P, She Y, Han L, Wan S, Shang W, Zhang Z, Min W. A promising biomarker of elevated galanin level in hypothalamus for osteoporosis risk in type 2 diabetes mellitus. Mech Ageing Dev 2020; 194:111427. [PMID: 33383074 DOI: 10.1016/j.mad.2020.111427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/15/2020] [Accepted: 12/20/2020] [Indexed: 02/07/2023]
Abstract
Type 2 diabetes mellitus (T2DM) and osteoporosis are two major healthcare problems worldwide. T2DM is considered to be a risk factor for osteoporosis. Interestingly, several epidemiological studies suggest that bone abnormalities associated with diabetes may differ, at least in part, from those associated with senile or post-menopausal osteoporosis. The growing prevalence that patients with T2DM simultaneously suffer from osteoporosis, puts forward the importance to discuss the relationship between both diseases, as well as to investigate correlative agents to treat them. Emerging evidences demonstrate that neuropeptide galanin is involved in the pathogenesis of T2DM and osteoporosis. Galanin via activation of central GALR2 increases insulin sensitivity as well as bone density and mass in animal models. The disorder of galanin function plays major role in development of both diseases. Importantly, galanin signaling is indispensable for ΔFosB, an AP1 antagonist, to play the bone mass-accruing effects in the ventral hypothalamic neurons of diabetic models. This review summarizes our and other recent studies to provide a new insight into the multivariate relationship among galanin, T2DM and osteoporosis, highlighting the beneficial effect of galanin on the comorbid state of both diseases. These may help us better understanding the pathogenesis of osteoporosis and T2DM and provide useful clues for further inquiry if elevated galanin level may be taken as a biomarker for both conjoint diseases, and GALR2 agonist may be taken as a novel therapeutic strategy to treat both diseases concurrently.
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Affiliation(s)
- Penghua Fang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China; Department of Physiology, Hanlin College, Nanjing University of Chinese Medicine, Taizhou 225300, China
| | - Yuqing She
- Department of Endocrinology, Pukou Branch of Jiangsu People's Hospital, Nanjing 211808, China
| | - Long Han
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Shiwei Wan
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wenbin Shang
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China.
| | - Wen Min
- Key Laboratory for Metabolic Diseases in Chinese Medicine, First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
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Lu X, Ru Y, Chu C, Lv Y, Gao Y, Jia Z, Huang Y, Zhang Y, Zhao S. Lentivirus-mediated IL-10-expressing Bone Marrow Mesenchymal Stem Cells promote corneal allograft survival via upregulating lncRNA 003946 in a rat model of corneal allograft rejection. Theranostics 2020; 10:8446-8467. [PMID: 32724480 PMCID: PMC7381730 DOI: 10.7150/thno.31711] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 06/10/2020] [Indexed: 12/16/2022] Open
Abstract
Rationale: Corneal transplantation is an effective treatment to corneal blindness. However, the immune rejection imperils corneal allograft survival. An interventional modality is urgently needed to inhibit immune rejection and promote allograft survival. In our previous study, subconjunctival injections of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a rat model of corneal allograft rejection extended allograft survival for 2 d. In this study, we sought to generate IL-10-overexpressing BM-MSCs, aiming to boost the survival-promoting effects of BM-MSCs on corneal allografts and explore the molecular and cellular mechanisms underlying augmented protection. Methods: A population of IL-10-overexpressing BM-MSCs (designated as IL-10-BM-MSCs) were generated by lentivirus transduction and FACS purification. The self-renewal, multi-differentiation, and immunoinhibitory capabilities of IL-10-BM-MSCs were examined by conventional assays. The IL-10-BM-MSCs were subconjunctivally injected into the model of corneal allograft rejection, and the allografts were monitored on a daily basis. The expression profiling of long noncoding RNA (lncRNA) in the allografts was revealed by RNA sequencing and verified by quantitative real-time PCR. The infiltrating immune cell type predominantly upregulating the lncRNA expression was identified by RNAscope in situ hybridization. The function of the upregulated lncRNA was proved by loss- and gain-of-function experiments both in vivo and in vitro. Results: The IL-10-BM-MSCs possessed an enhanced immunoinhibitory capability and unabated self-renewal and multi-differentiation potentials as compared to plain BM-MSCs. The subconjunctivally injected IL-10-BM-MSCs reduced immune cell infiltration and doubled allograft survival time (20 d) as compared to IL-10 protein or plain BM-MSCs in the corneal allograft rejection model. Further, IL-10-BM-MSCs significantly upregulated lncRNA 003946 expression in CD68+ macrophages infiltrating corneal allografts. Silencing and overexpressing lncRNA 003946 in macrophage cultures abolished and mimicked the IL-10-BM-MSCs' suppressing effects on the macrophages' antigen presentation, respectively. In parallel, knocking down and overexpressing the lncRNA in vivo abrogated and simulated the survival-promoting effects of IL-10-BM-MSCs on corneal allografts, respectively. Conclusion: The remarkable protective effects of IL-10-BM-MSCs support further developing them into an effective interventional modality against corneal allograft rejection. IL-10-BM-MSCs promote corneal allograft survival mainly through upregulating a novel lncRNA expression in graft-infiltrating CD68+ macrophages. LncRNA, for the first time, is integrated into an IL-10-BM-MSC-driven immunomodulatory axis against the immune rejection to corneal allograft.
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19
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Le B, Cheng X, Qu S. Cooperative effects of galanin and leptin on alleviation of insulin resistance in adipose tissue of diabetic rats. J Cell Mol Med 2020; 24:6773-6780. [PMID: 32395890 PMCID: PMC7299679 DOI: 10.1111/jcmm.15328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/29/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
It was reported that either orexigenic neuropeptide galanin or anorexigenic hormone leptin caught benefit insulin sensitivity through increasing the translocation of glucose transporter 4 (GLUT4) in patients with diabetes. To date, it is unknown whether galanin can potentiate the effect of leptin on alleviation of insulin resistance. Therefore, in the current study we sought to assess the combined effect of central leptin and galanin on insulin resistance in the adipose tissues of type 2 diabetic rats. Galanin and leptin were injected into the intracerebroventricle of the diabetic rats, respectively, or cooperatively once a day for 2 weeks. Then, several indexes of insulin resistance were examined. The results showed that glucose infusion rates in the hyperinsulinaemic-euglycaemic clamp test, plasma adiponectin content and GLUT4 translocation, as well as Akt phosphorylation in fat cells, were higher, not GLUT4 protein and GLUT4 mRNA expression, but HOMA index was lower in the galanin + leptin group than either one of them. Furthermore, treatment with MK-2206, an Akt inhibitor, blocked the combined effects of galanin + leptin on alleviation of insulin resistance. These results suggest that galanin can improve the leptin-induced mitigative effects on insulin resistance in the fat cells, and those provided new insights into the potential tactics for prevention and remedy of insulin resistance.
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Affiliation(s)
- Bu Le
- Department of EndocrinologyShanghai 10th People HospitalTongji University School of MedicineShanghaiChina
| | - Xiaoyun Cheng
- Department of EndocrinologyShanghai 10th People HospitalTongji University School of MedicineShanghaiChina
| | - Shen Qu
- Department of EndocrinologyShanghai 10th People HospitalTongji University School of MedicineShanghaiChina
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20
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Perez-Bonilla P, Santiago-Colon K, Leinninger GM. Lateral hypothalamic area neuropeptides modulate ventral tegmental area dopamine neurons and feeding. Physiol Behav 2020; 223:112986. [PMID: 32492498 DOI: 10.1016/j.physbeh.2020.112986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 01/26/2023]
Abstract
Understanding how the brain coordinates energy status with the motivation to eat is crucial to identify strategies to improve disordered body weight. The ventral tegmental area (VTA), known as the core of the mesolimbic system, is of particular interest in this regard because it controls the motivation to consume palatable, calorie-dense foods and to engage in volitional activity. The VTA is largely composed of dopamine (DA) neurons, but modulating these DA neurons has been alternately linked with promoting and suppressing feeding, suggesting heterogeneity in their function. Subsets of VTA DA neurons have recently been described based on their anatomical distribution, electrophysiological features, connectivity and molecular expression, but to date there are no signatures to categorize how DA neurons control feeding. Assessing the neuropeptide receptors expressed by VTA DA neurons may be useful in this regard, as many neuropeptides mediate anorexic or orexigenic responses. In particular, the lateral hypothalamic area (LHA) releases a wide variety of feeding-modulating neuropeptides to the VTA. Since VTA neurons intercept LHA neuropeptides known to either evoke or suppress feeding, expression of the cognate neuropeptide receptors within the VTA may point to VTA DA neuronal mechanisms to promote or suppress feeding, respectively. Here we review the role of the VTA in energy balance and the LHA neuropeptide signaling systems that act in the VTA, whose receptors might be used to classify how VTA DA neurons contribute to energy balance.
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Affiliation(s)
- Patricia Perez-Bonilla
- Neuroscience Graduate Program, USA; Pharmacology and Toxicology Graduate Program, USA; Michigan State University, East Lansing, MI 48114, USA
| | - Krystal Santiago-Colon
- Department of Biology, University of Puerto Rico - Cayey, USA; Bridge to the PhD in Neuroscience Program, USA
| | - Gina M Leinninger
- Department of Physiology, USA; Michigan State University, East Lansing, MI 48114, USA.
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21
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Federighi G, Asteriti S, Cangiano L. Lumbar spinal cord neurons putatively involved in ejaculation are sexually dimorphic in early postnatal mice. J Comp Neurol 2020; 528:624-636. [PMID: 31566721 DOI: 10.1002/cne.24776] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 01/23/2023]
Abstract
A crucial role in ejaculation is thought to be played by a population of lumbar spino-thalamic neurons (LSt), which express galanin and other neuropeptides. In rats, these neurons are activated with ejaculation and their lesion selectively abolishes ejaculation but not other mating behaviors. Consistently with their role, in adult rats and humans, LSt neurons are sexually dimorphic, being more numerous in males. Here we examined whether sexual dimorphism arises early in development, using a transgenic mouse line in which the expression of fluorescent protein is driven by the galanin promoter. We focused on postnatal day 4, shortly after a transient perinatal androgen surge in males that could play an organizational role in LSt development. We found a population of brightly fluorescent neurons organized in bilateral columns dorsolateral to the central canal in segments L1-L5, the expected location of the LSt group. Their number was close to that of adult preparations and significantly greater in male than in female siblings (+19%; CI95% : +13% to +27%; p < .01). This was not due to a generalized higher galanin expression in the male since fluorescent L4 DRG neurons, innervating the hindlimbs and lower back, were not significantly dimorphic (-4%; CI95% : -10% to +8%; p = .92). Unexpectedly, we found in cervical segments a population of fluorescent neurons having a location relative to the central canal similar to the LSt. Thus, the LSt group is sexually dimorphic soon after birth. However, it is possible that only a subset of its neurons participate in the control of ejaculation.
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Affiliation(s)
| | - Sabrina Asteriti
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Lorenzo Cangiano
- Department of Translational Research, University of Pisa, Pisa, Italy
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22
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Fakhoury M, Salman I, Najjar W, Merhej G, Lawand N. The Lateral Hypothalamus: An Uncharted Territory for Processing Peripheral Neurogenic Inflammation. Front Neurosci 2020; 14:101. [PMID: 32116534 PMCID: PMC7029733 DOI: 10.3389/fnins.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
The roles of the hypothalamus and particularly the lateral hypothalamus (LH) in the regulation of inflammation and pain have been widely studied. The LH consists of a parasympathetic area that has connections with all the major parts of the brain. It controls the autonomic nervous system (ANS), regulates feeding behavior and wakeful cycles, and is a part of the reward system. In addition, it contains different types of neurons, most importantly the orexin neurons. These neurons, though few in number, perform critical functions such as inhibiting pain transmission and interfering with the reward system, feeding behavior and the hypothalamic pituitary axis (HPA). Recent evidence has identified a new role for orexin neurons in the modulation of pain transmission associated with several inflammatory diseases, including rheumatoid arthritis and ulcerative colitis. Here, we review recent findings on the various physiological functions of the LH with special emphasis on the orexin/receptor system and its role in mediating inflammatory pain.
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Affiliation(s)
- Marc Fakhoury
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Israa Salman
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Najjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - George Merhej
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nada Lawand
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Neurology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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23
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Leidmaa E, Gazea M, Patchev AV, Pissioti A, Christian Gassen N, Kimura M, Liposits Z, Kallo I, Almeida OFX. Blunted leptin sensitivity during hedonic overeating can be reinstated by activating galanin 2 receptors (Gal2R) in the lateral hypothalamus. Acta Physiol (Oxf) 2020; 228:e13345. [PMID: 31310704 DOI: 10.1111/apha.13345] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
AIM Since foods with high hedonic value are often consumed in excess of energetic needs, this study was designed to identify the mechanisms that may counter anorexigenic signalling in the presence of hedonic foods in lean animals. METHODS Mice, in different states of satiety (fed/fasted, or fed/fasted and treated with ghrelin or leptin, respectively), were allowed to choose between high-fat/high-sucrose and standard foods. Intake of each food type and the activity of hypothalamic neuropetidergic neurons that regulate appetite were monitored. In some cases, food choice was monitored in leptin-injected fasted mice that received microinjections of galanin receptor agonists into the lateral hypothalamus. RESULTS Appetite-stimulating orexin neurons in the lateral hypothalamus are rapidly activated when lean, satiated mice consume a highly palatable food (PF); such activation (upregulated c-Fos expression) occurred even after administration of the anorexigenic hormone leptin and despite intact leptin signalling in the hypothalamus. The ability of leptin to restrain PF eating is restored when a galanin receptor 2 (Gal2R) agonist is injected into the lateral hypothalamus. CONCLUSION Hedonically-loaded foods interrupt the inhibitory actions of leptin on orexin neurons and interfere with the homeostatic control of feeding. Overeating of palatable foods can be curtailed in lean animals by activating Gal2R in the lateral hypothalamus.
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Affiliation(s)
- Este Leidmaa
- Max Planck Institute of Psychiatry Munich Germany
- Graduate School of Systems Neuroscience Munich University Planegg‐Martinsried Germany
- Institute of Molecular Psychiatry Bonn Germany
| | - Mary Gazea
- Max Planck Institute of Psychiatry Munich Germany
| | | | | | | | | | - Zsolt Liposits
- Institute of Experimental Medicine Hungarian Academy of Sciences Budapest Hungary
| | - Imre Kallo
- Institute of Experimental Medicine Hungarian Academy of Sciences Budapest Hungary
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24
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Galanin peptide family regulation of glucose metabolism. Front Neuroendocrinol 2020; 56:100801. [PMID: 31705911 DOI: 10.1016/j.yfrne.2019.100801] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/09/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022]
Abstract
Recent preclinical and clinical studies have indicated that the galanin peptide family may regulate glucose metabolism and alleviate insulin resistance, which diminishes the probability of type 2 diabetes mellitus. The galanin was discovered in 1983 as a gut-derived peptide hormone. Subsequently, galanin peptide family was found to exert a series of metabolic effects, including the regulation of gut motility, body weight and glucose metabolism. The galanin peptide family in modulating glucose metabolism received recently increasing recognition because pharmacological activiation of galanin signaling might be of therapeutic value to improve insuin resistance and type 2 diabetes mellitus. To date, however, few papers have summarized the role of the galanin peptide family in modulating glucose metabolism and insulin resistance. In this review we summarize the metabolic effect of galanin peptide family and highlight its glucoregulatory action and discuss the pharmacological value of galanin pathway activiation for the treatment of glucose intolerance and type 2 diabetes mellitus.
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25
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Idelevich A, Sato K, Nagano K, Rowe G, Gori F, Baron R. ΔFosB Requires Galanin, but not Leptin, to Increase Bone Mass via the Hypothalamus, but both are needed to increase Energy expenditure. J Bone Miner Res 2019; 34:1707-1720. [PMID: 30998833 PMCID: PMC6744351 DOI: 10.1002/jbmr.3741] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/22/2019] [Accepted: 04/05/2019] [Indexed: 01/29/2023]
Abstract
Energy metabolism and bone homeostasis share several regulatory pathways. The AP1 transcription factor ΔFosB and leptin both regulate energy metabolism and bone, yet whether their pathways intersect is not known. Transgenic mice overexpressing ΔFosB under the control of the Enolase 2 (ENO2) promoter exhibit high bone mass, high energy expenditure, low fat mass, and low circulating leptin levels. Because leptin is a regulator of bone and ΔFosB acts on leptin-responsive ventral hypothalamic (VHT) neurons to induce bone anabolism, we hypothesized that regulation of leptin may contribute to the central actions of ΔFosB in the VHT. To address this question, we used adeno-associated virus (AAV) expression of ΔFosB in the VHT of leptin-deficient ob/ob mice and genetic crossing of ENO2-ΔFosB with ob/ob mice. In both models, leptin deficiency prevented ΔFosB-triggered reduction in body weight, increase in energy expenditure, increase in glucose utilization, and reduction in pancreatic islet size. In contrast, leptin deficiency failed to prevent ΔFosB-triggered increase in bone mass. Unlike leptin deficiency, galanin deficiency blocked both the metabolic and the bone ΔFosB-induced effects. Overall, our data demonstrate that, while the catabolic energy metabolism effects of ΔFosB require intact leptin and galanin signaling, the bone mass-accruing effects of ΔFosB require galanin but are independent of leptin. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Anna Idelevich
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Kazusa Sato
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Kenichi Nagano
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Glenn Rowe
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Francesca Gori
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Roland Baron
- Department of Medicine, Harvard Medical School and Endocrine Unit, Massachusetts General Hospital, and Division of Bone and Mineral Metabolism, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
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Godfrey N, Borgland SL. Diversity in the lateral hypothalamic input to the ventral tegmental area. Neuropharmacology 2019; 154:4-12. [DOI: 10.1016/j.neuropharm.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/15/2019] [Accepted: 05/13/2019] [Indexed: 12/29/2022]
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Schroeder LE, Furdock R, Quiles CR, Kurt G, Perez-Bonilla P, Garcia A, Colon-Ortiz C, Brown J, Bugescu R, Leinninger GM. [Not Available]. Neuropeptides 2019; 76:101930. [PMID: 31079844 PMCID: PMC7721284 DOI: 10.1016/j.npep.2019.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022]
Abstract
Neurotensin (Nts) is a neuropeptide implicated in the regulation of many facets of physiology, including cardiovascular tone, pain processing, ingestive behaviors, locomotor drive, sleep, addiction and social behaviors. Yet, there is incomplete understanding about how the various populations of Nts neurons distributed throughout the brain mediate such physiology. This knowledge gap largely stemmed from the inability to simultaneously identify Nts cell bodies and manipulate them in vivo. One means of overcoming this obstacle is to study NtsCre mice crossed onto a Cre-inducible green fluorescent reporter line (NtsCre;GFP mice), as these mice permit both visualization and in vivo modulation of specific populations of Nts neurons (using Cre-inducible viral and genetic tools) to reveal their function. Here we provide a comprehensive characterization of the distribution and relative densities of the Nts-GFP populations observed throughout the male NtsCre;GFP mouse brain, which will pave the way for future work to define their physiologic roles. We also compared the distribution of Nts-GFP neurons with Nts-In situ Hybridization (Nts-ISH) data from the adult mouse brain. By comparing these data sets we can distinguish Nts-GFP populations that may only transiently express Nts during development but not in the mature brain, and hence which populations may not be amenable to Cre-mediated manipulation in adult NtsCre;GFP mice. This atlas of Nts-GFP neurons will facilitate future studies using the NtsCre;GFP line to describe the physiological functions of individual Nts populations and how modulating them may be useful to treat disease.
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Affiliation(s)
- Laura E Schroeder
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Ryan Furdock
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Cristina Rivera Quiles
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Gizem Kurt
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Patricia Perez-Bonilla
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Angela Garcia
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Crystal Colon-Ortiz
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Juliette Brown
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States
| | - Gina M Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI 48114, United States.
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Schiffino FL, Siemian JN, Petrella M, Laing BT, Sarsfield S, Borja CB, Gajendiran A, Zuccoli ML, Aponte Y. Activation of a lateral hypothalamic-ventral tegmental circuit gates motivation. PLoS One 2019; 14:e0219522. [PMID: 31291348 PMCID: PMC6619795 DOI: 10.1371/journal.pone.0219522] [Citation(s) in RCA: 15] [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: 03/26/2019] [Accepted: 06/25/2019] [Indexed: 02/06/2023] Open
Abstract
Across species, motivated states such as food-seeking and consumption are essential for survival. The lateral hypothalamus (LH) is known to play a fundamental role in regulating feeding and reward-related behaviors. However, the contributions of neuronal subpopulations in the LH have not been thoroughly identified. Here we examine how lateral hypothalamic leptin receptor-expressing (LHLEPR) neurons, a subset of GABAergic cells, regulate motivation in mice. We find that LHLEPR neuronal activation significantly increases progressive ratio (PR) performance, while inhibition decreases responding. Moreover, we mapped LHLEPR axonal projections and demonstrated that they target the ventral tegmental area (VTA), form functional inhibitory synapses with non-dopaminergic VTA neurons, and their activation promotes motivation for food. Finally, we find that LHLEPR neurons also regulate motivation to obtain water, suggesting that they may play a generalized role in motivation. Together, these results identify LHLEPR neurons as modulators within a hypothalamic-ventral tegmental circuit that gates motivation.
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Affiliation(s)
- Felipe L. Schiffino
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Justin N. Siemian
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Michele Petrella
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
- Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino (MC), Italy
| | - Brenton T. Laing
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Sarah Sarsfield
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Cara B. Borja
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Anjali Gajendiran
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Maria Laura Zuccoli
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Yeka Aponte
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland, United States of America
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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29
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de Vrind VA, Rozeboom A, Wolterink‐Donselaar IG, Luijendijk‐Berg MC, Adan RA. Effects of GABA and Leptin Receptor-Expressing Neurons in the Lateral Hypothalamus on Feeding, Locomotion, and Thermogenesis. Obesity (Silver Spring) 2019; 27:1123-1132. [PMID: 31087767 PMCID: PMC6617814 DOI: 10.1002/oby.22495] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/28/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The lateral hypothalamus (LH) is known for its role in feeding, and it also regulates other aspects of energy homeostasis. How genetically defined LH neuronal subpopulations mediate LH effects on energy homeostasis remains poorly understood. The behavioral effects of chemogenetically activating LH gamma-aminobutyric acid (GABA) and the more selective population of LH GABA neurons that coexpress the leptin receptor (LepR) were compared. METHODS LepR-cre and VGAT-cre mice were injected with AAV5-hSyn-DIO-hM3DGq-mCherry in the LH. The behavioral effects of LH GABA or LH LepR neuronal activation on feeding, locomotion, thermogenesis, and body weight were assessed. RESULTS The activation of LH GABA neurons increased body temperature (P ≤ 0.008) and decreased body weight (P ≤ 0.01) despite decreased locomotor activity (P = 0.03) and transiently increased chow intake (P ≤ 0.009). Also, similar to other studies, this study found that activation of LH GABA neurons induced gnawing on both food and nonfood (P = 0.001) items. Activation of LH LepR neurons decreased body weight (P ≤ 0.01) and chow intake when presented on the cage floor (P ≤ 0.04) but not when presented in the cage top and increased locomotor activity (P = 0.002) and body temperature (P = 0.03). CONCLUSIONS LH LepR neurons are a subset of LH GABA neurons, and LH LepR activation more specifically regulates energy homeostasis to promote a negative energy balance.
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Affiliation(s)
- Véronne A.J. de Vrind
- Brain Center Rudolf Magnus, Department of Translational NeuroscienceUniversity Medical Center Utrecht and University UtrechtUtrechtThe Netherlands
| | - Annemieke Rozeboom
- Brain Center Rudolf Magnus, Department of Translational NeuroscienceUniversity Medical Center Utrecht and University UtrechtUtrechtThe Netherlands
| | - Inge G. Wolterink‐Donselaar
- Brain Center Rudolf Magnus, Department of Translational NeuroscienceUniversity Medical Center Utrecht and University UtrechtUtrechtThe Netherlands
| | - Mieneke C.M. Luijendijk‐Berg
- Brain Center Rudolf Magnus, Department of Translational NeuroscienceUniversity Medical Center Utrecht and University UtrechtUtrechtThe Netherlands
| | - Roger A.H. Adan
- Brain Center Rudolf Magnus, Department of Translational NeuroscienceUniversity Medical Center Utrecht and University UtrechtUtrechtThe Netherlands
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of GothenburgGothenburgSweden
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30
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Mickelsen LE, Bolisetty M, Chimileski BR, Fujita A, Beltrami EJ, Costanzo JT, Naparstek JR, Robson P, Jackson AC. Single-cell transcriptomic analysis of the lateral hypothalamic area reveals molecularly distinct populations of inhibitory and excitatory neurons. Nat Neurosci 2019; 22:642-656. [PMID: 30858605 DOI: 10.1038/s41593-019-0349-8] [Citation(s) in RCA: 190] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 01/30/2019] [Indexed: 01/01/2023]
Abstract
The lateral hypothalamic area (LHA) coordinates an array of fundamental behaviors, including sleeping, waking, feeding, stress and motivated behavior. The wide spectrum of functions ascribed to the LHA may be explained by a heterogeneous population of neurons, the full diversity of which is poorly understood. We employed a droplet-based single-cell RNA-sequencing approach to develop a comprehensive census of molecularly distinct cell types in the mouse LHA. Neuronal populations were classified based on fast neurotransmitter phenotype and expression of neuropeptides, transcription factors and synaptic proteins, among other gene categories. We define 15 distinct populations of glutamatergic neurons and 15 of GABAergic neurons, including known and novel cell types. We further characterize a novel population of somatostatin-expressing neurons through anatomical and behavioral approaches, identifying a role for these neurons in specific forms of innate locomotor behavior. This study lays the groundwork for better understanding the circuit-level underpinnings of LHA function.
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Affiliation(s)
- Laura E Mickelsen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.,Connecticut Institute for the Brain and Cognitive Sciences, Storrs, CT, USA
| | - Mohan Bolisetty
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.,Bristol-Myers Squibb, Pennington, NJ, USA
| | - Brock R Chimileski
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Akie Fujita
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.,Connecticut Institute for the Brain and Cognitive Sciences, Storrs, CT, USA.,Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA
| | - Eric J Beltrami
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - James T Costanzo
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Jacob R Naparstek
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Paul Robson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA. .,Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, USA.
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA. .,Connecticut Institute for the Brain and Cognitive Sciences, Storrs, CT, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, USA.
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Pei H, Patterson CM, Sutton AK, Burnett KH, Myers MG, Olson DP. Lateral Hypothalamic Mc3R-Expressing Neurons Modulate Locomotor Activity, Energy Expenditure, and Adiposity in Male Mice. Endocrinology 2019; 160:343-358. [PMID: 30541071 PMCID: PMC6937456 DOI: 10.1210/en.2018-00747] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/04/2018] [Indexed: 02/05/2023]
Abstract
The central melanocortin system plays a crucial role in the control of energy balance. Although the decreased energy expenditure and increased adiposity of melanocortin-3 receptor (Mc3R)-null mice suggest the importance of Mc3R-regulated neurons in energy homeostasis, the roles for specific subsets of Mc3R neurons in energy balance have yet to be determined. Because the lateral hypothalamic area (LHA) contributes to the control of energy expenditure and feeding, we generated Mc3rcre mice to determine the roles of LHA Mc3R (Mc3RLHA) neurons in energy homeostasis. We found that Mc3RLHA neurons overlap extensively with LHA neuron markers that contribute to the control of energy balance (neurotensin, galanin, and leptin receptor) and project to brain areas involved in the control of feeding, locomotion, and energy expenditure, consistent with potential roles for Mc3RLHA neurons in these processes. Indeed, selective chemogenetic activation of Mc3RLHA neurons increased locomotor activity and augmented refeeding after a fast. Although the ablation of Mc3RLHA neurons did not alter food intake, mice lacking Mc3RLHA neurons displayed decreased energy expenditure and locomotor activity, along with increased body mass and adiposity. Thus, Mc3R neurons lie within LHA neurocircuitry that modulates locomotor activity and energy expenditure and contribute to energy balance control.
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Affiliation(s)
- Hongjuan Pei
- Division of Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, Michigan
| | | | - Amy K Sutton
- Molecular and Integrative Physiology, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
| | - Korri H Burnett
- Division of Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, Michigan
| | - Martin G Myers
- Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan
- Molecular and Integrative Physiology, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
| | - David P Olson
- Division of Endocrinology, Department of Pediatrics, Michigan Medicine, Ann Arbor, Michigan
- Molecular and Integrative Physiology, Michigan Medicine, University of Michigan, Ann Arbor, Michigan
- Correspondence: David P. Olson, MD, PhD, University of Michigan, 1000 Wall Street, Brehm Tower 6329, Ann Arbor, Michigan 48105. E-mail:
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Arrigoni E, Chee MJS, Fuller PM. To eat or to sleep: That is a lateral hypothalamic question. Neuropharmacology 2018; 154:34-49. [PMID: 30503993 DOI: 10.1016/j.neuropharm.2018.11.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
Abstract
The lateral hypothalamus (LH) is a functionally and anatomically complex brain region that is involved in the regulation of many behavioral and physiological processes including feeding, arousal, energy balance, stress, reward and motivated behaviors, pain perception, body temperature regulation, digestive functions and blood pressure. Despite noteworthy experimental efforts over the past decades, the circuit, cellular and synaptic bases by which these different processes are regulated by the LH remains incompletely understood. This knowledge gap links in large part to the high cellular heterogeneity of the LH. Fortunately, the rapid evolution of newer genetic and electrophysiological tools is now permitting the selective manipulation, typically genetically-driven, of discrete LH cell populations. This, in turn, permits not only assignment of function to discrete cell groups, but also reveals that considerable synergistic and antagonistic interactions exist between key LH cell populations that regulate feeding and arousal. For example, we now know that while LH melanin-concentrating hormone (MCH) and orexin/hypocretin neurons both function as sensors of the internal metabolic environment, their roles regulating sleep and arousal are actually opposing. Additional studies have uncovered similarly important roles for subpopulations of LH GABAergic cells in the regulation of both feeding and arousal. Herein we review the role of LH MCH, orexin/hypocretin and GABAergic cell populations in the regulation of energy homeostasis (including feeding) and sleep-wake and discuss how these three cell populations, and their subpopulations, may interact to optimize and coordinate metabolism, sleep and arousal. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA.
| | - Melissa J S Chee
- Department of Neuroscience, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA
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Qualls-Creekmore E, Münzberg H. Modulation of Feeding and Associated Behaviors by Lateral Hypothalamic Circuits. Endocrinology 2018; 159:3631-3642. [PMID: 30215694 PMCID: PMC6195675 DOI: 10.1210/en.2018-00449] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 09/05/2018] [Indexed: 12/15/2022]
Abstract
Our ability to modulate and observe neuronal activity in defined neurons in freely moving animals has revolutionized neuroscience research in recent years. Findings in the lateral hypothalamus (LHA) highlighted the existence of many neuronal circuits that regulate distinct phenotypes of feeding behavior, emotional valence, and locomotor activity. Several of these neuronal circuits do not fit into a common model of neuronal integration and highlight the need to improve working models for complex behaviors. This review will specifically focus on recent literature that distinguishes LHA circuits based on their molecular and anatomical characteristics and studies their role in feeding, associated behaviors (e.g., arousal and locomotion), and emotional states (e.g., emotional valences).
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Affiliation(s)
- Emily Qualls-Creekmore
- Neurobiology of Nutrition and Metabolism, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Heike Münzberg
- Neurobiology of Nutrition and Metabolism, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
- Correspondence: Heike Münzberg, PhD, Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, Louisiana 70808. E-mail:
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Kurt G, Woodworth HL, Fowler S, Bugescu R, Leinninger GM. Activation of lateral hypothalamic area neurotensin-expressing neurons promotes drinking. Neuropharmacology 2018; 154:13-21. [PMID: 30266601 DOI: 10.1016/j.neuropharm.2018.09.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/04/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022]
Abstract
Animals must ingest water via drinking to maintain fluid homeostasis, yet the neurons that specifically promote drinking behavior are incompletely characterized. The lateral hypothalamic area (LHA) as a whole is essential for drinking behavior but most LHA neurons indiscriminately promote drinking and feeding. By contrast, activating neurotensin (Nts)-expressing LHA neurons (termed LHA Nts neurons) causes mice to immediately drink water with a delayed suppression of feeding. We therefore hypothesized that LHA Nts neurons are sufficient to induce drinking behavior and that these neurons specifically bias for fluid intake over food intake. To test this hypothesis we used designer receptors exclusively activated by designer drugs (DREADDs) to selectively activate LHA Nts neurons and studied the impact on fluid intake, fluid preference and feeding. Activation of LHA Nts neurons stimulated drinking in water-replete and dehydrated mice, indicating that these neurons are sufficient to promote water intake regardless of homeostatic need. Interestingly, mice with activated LHA Nts neurons drank any fluid that was provided regardless of its palatability, but if given a choice they preferred water or palatable solutions over unpalatable (quinine) or dehydrating (hypertonic saline) solutions. Notably, acute activation of LHA Nts neurons robustly promoted fluid but not food intake. Overall, our study confirms that activation of LHA Nts neurons is sufficient to induce drinking behavior and biases for fluid intake. Hence, LHA Nts neurons may be important targets for orchestrating the appropriate ingestive behavior necessary to maintain fluid homeostasis. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Gizem Kurt
- Department of Physiology, Michigan State University, East Lansing, MI, 48114, USA
| | - Hillary L Woodworth
- Department of Physiology, Michigan State University, East Lansing, MI, 48114, USA
| | - Sabrina Fowler
- Department of Physiology, Michigan State University, East Lansing, MI, 48114, USA
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI, 48114, USA
| | - Gina M Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI, 48114, USA.
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Clarke RE, Verdejo-Garcia A, Andrews ZB. The role of corticostriatal-hypothalamic neural circuits in feeding behaviour: implications for obesity. J Neurochem 2018; 147:715-729. [PMID: 29704424 DOI: 10.1111/jnc.14455] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/11/2018] [Accepted: 04/13/2018] [Indexed: 02/02/2023]
Abstract
Emerging evidence from human imaging studies suggests that obese individuals have altered connectivity between the hypothalamus, the key brain region controlling energy homeostasis, and cortical regions involved in decision-making and reward processing. Historically, animal studies have demonstrated that the lateral hypothalamus is the key hypothalamic region involved in feeding and reward. The lateral hypothalamus is a heterogeneous structure comprised of several distinct types of neurons which are scattered throughout. In addition, the lateral hypothalamus receives inputs from a number of cortical brain regions suggesting that it is uniquely positioned to be a key integrator of cortical information and metabolic feedback. In this review, we summarize how human brain imaging can inform detailed animal studies to investigate neural pathways connecting cortical regions and the hypothalamus. Here, we discuss key cortical brain regions that are reciprocally connected to the lateral hypothalamus and are implicated in decision-making processes surrounding food.
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Affiliation(s)
- Rachel E Clarke
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia.,Department of Physiology, Monash University, Clayton, Vic., Australia
| | - Antonio Verdejo-Garcia
- Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Clayton, Vic., Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia.,Department of Physiology, Monash University, Clayton, Vic., Australia
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Tsuneki H, Wada T, Sasaoka T. Chronopathophysiological implications of orexin in sleep disturbances and lifestyle-related disorders. Pharmacol Ther 2018; 186:25-44. [DOI: 10.1016/j.pharmthera.2017.12.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Interactions between the brain and distinct adipose depots have a key role in maintaining energy balance, thereby promoting survival in response to metabolic challenges such as cold exposure and starvation. Recently, there has been renewed interest in the specific central neuronal circuits that regulate adipose depots. Here, we review anatomical, genetic and pharmacological studies on the neural regulation of adipose function, including lipolysis, non-shivering thermogenesis, browning and leptin secretion. In particular, we emphasize the role of leptin-sensitive neurons and the sympathetic nervous system in modulating the activity of brown, white and beige adipose tissues. We provide an overview of advances in the understanding of the heterogeneity of the brain regulation of adipose tissues and offer a perspective on the challenges and paradoxes that the community is facing regarding the actions of leptin on this system.
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Affiliation(s)
- Alexandre Caron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Syann Lee
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joel K. Elmquist
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Laurent Gautron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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Yuan X, Caron A, Wu H, Gautron L. Leptin Receptor Expression in Mouse Intracranial Perivascular Cells. Front Neuroanat 2018; 12:4. [PMID: 29410615 PMCID: PMC5787097 DOI: 10.3389/fnana.2018.00004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/08/2018] [Indexed: 12/28/2022] Open
Abstract
Past studies have suggested that non-neuronal brain cells express the leptin receptor. However, the identity and distribution of these leptin receptor-expressing non-neuronal brain cells remain debated. This study assessed the distribution of the long form of the leptin receptor (LepRb) in non-neuronal brain cells using a reporter mouse model in which LepRb-expressing cells are permanently marked by tdTomato fluorescent protein (LepRb-CretdTomato). Double immunohistochemistry revealed that, in agreement with the literature, the vast majority of tdTomato-tagged cells across the mouse brain were neurons (i.e., based on immunoreactivity for NeuN). Non-neuronal structures also contained tdTomato-positive cells, including the choroid plexus and the perivascular space of the meninges and, to a lesser extent, the brain. Based on morphological criteria and immunohistochemistry, perivascular cells were deduced to be mainly pericytes. Notably, tdTomato-positive cells were immunoreactive for vitronectin and platelet derived growth factor receptor beta (PDGFBR). In situ hybridization studies confirmed that most tdTomato-tagged perivascular cells were enriched in leptin receptor mRNA (all isoforms). Using qPCR studies, we confirmed that the mouse meninges were enriched in Leprb and, to a greater extent, the short isoforms of the leptin receptor. Interestingly, qPCR studies further demonstrated significantly altered expression for Vtn and Pdgfrb in the meninges and hypothalamus of LepRb-deficient mice. Collectively, our data demonstrate that the only intracranial non-neuronal cells that express LepRb in the adult mouse are cells that form the blood-brain barrier, including, most notably, meningeal perivascular cells. Our data suggest that pericytic leptin signaling plays a role in the integrity of the intracranial perivascular space and, consequently, may provide a link between obesity and numerous brain diseases.
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Affiliation(s)
- Xuefeng Yuan
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Alexandre Caron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Hua Wu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Laurent Gautron
- Division of Hypothalamic Research and Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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Regulation of Lateral Hypothalamic Orexin Activity by Local GABAergic Neurons. J Neurosci 2018; 38:1588-1599. [PMID: 29311142 DOI: 10.1523/jneurosci.1925-17.2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/04/2017] [Accepted: 12/27/2017] [Indexed: 12/31/2022] Open
Abstract
Orexin (also known as hypocretin) neurons are considered a key component of the ascending arousal system. They are active during wakefulness, at which time they drive and maintain arousal, and are silent during sleep. Their activity is controlled by long-range inputs from many sources, as well as by more short-range inputs, including from presumptive GABAergic neurons in the lateral hypothalamus/perifornical region (LH/PF). To characterize local GABAergic input to orexin neurons, we used channelrhodopsin-2-assisted circuit mapping in brain slices. We expressed channelrhodopsin-2 in GABAergic neurons (Vgat+) in the LH/PF and recorded from genetically identified surrounding orexin neurons (LH/PFVgat → Orx). We performed all experiments in mice of either sex. Photostimulation of LH/PF GABAergic neurons inhibited the firing of orexin neurons through the release of GABA, evoking GABAA-mediated IPSCs in orexin neurons. These photo-evoked IPSCs were maintained in the presence of TTX, indicating direct connectivity. Carbachol inhibited LH/PFVgat → Orx input through muscarinic receptors. By contrast, application of orexin was without effect on LH/PFVgat → Orx input, whereas dynorphin, another peptide produced by orexin neurons, inhibited LH/PFVgat → Orx input through κ-opioid receptors. Our results demonstrate that orexin neurons are under inhibitory control by local GABAergic neurons and that this input is depressed by cholinergic signaling, unaffected by orexin and inhibited by dynorphin. We propose that local release of dynorphin may, via collaterals, provides a positive feedback to orexin neurons and that, during wakefulness, orexin neurons may be disinhibited by acetylcholine and by their own release of dynorphin.SIGNIFICANCE STATEMENT The lateral hypothalamus contains important wake-promoting cell populations, including orexin-producing neurons. Intermingled with the orexin neurons, there are other cell populations that selectively discharge during nonrapid eye movement or rapid eye movement sleep. Some of these sleep-active neurons release GABA and are thought to inhibit wake-active neurons during rapid eye movement and nonrapid eye movement sleep. However, this hypothesis had not been tested. Here we show that orexin neurons are inhibited by a local GABAergic input. We propose that this local GABAergic input inhibits orexin neurons during sleep but that, during wakefulness, this input is depressed, possibly through cholinergically mediated disinhibition and/or by release of dynorphin from orexin neurons themselves.
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Neurochemical Heterogeneity Among Lateral Hypothalamic Hypocretin/Orexin and Melanin-Concentrating Hormone Neurons Identified Through Single-Cell Gene Expression Analysis. eNeuro 2017; 4:eN-NWR-0013-17. [PMID: 28966976 PMCID: PMC5617207 DOI: 10.1523/eneuro.0013-17.2017] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 08/14/2017] [Accepted: 08/25/2017] [Indexed: 02/06/2023] Open
Abstract
The lateral hypothalamic area (LHA) lies at the intersection of multiple neural and humoral systems and orchestrates fundamental aspects of behavior. Two neuronal cell types found in the LHA are defined by their expression of hypocretin/orexin (Hcrt/Ox) and melanin-concentrating hormone (MCH) and are both important regulators of arousal, feeding, and metabolism. Conflicting evidence suggests that these cell populations have a more complex signaling repertoire than previously appreciated, particularly in regard to their coexpression of other neuropeptides and the machinery for the synthesis and release of GABA and glutamate. Here, we undertook a single-cell expression profiling approach to decipher the neurochemical phenotype, and heterogeneity therein, of Hcrt/Ox and MCH neurons. In transgenic mouse lines, we used single-cell quantitative polymerase chain reaction (qPCR) to quantify the expression of 48 key genes, which include neuropeptides, fast neurotransmitter components, and other key markers, which revealed unexpected neurochemical diversity. We found that single MCH and Hcrt/Ox neurons express transcripts for multiple neuropeptides and markers of both excitatory and inhibitory fast neurotransmission. Virtually all MCH and approximately half of the Hcrt/Ox neurons sampled express both the machinery for glutamate release and GABA synthesis in the absence of a vesicular GABA release pathway. Furthermore, we found that this profile is characteristic of a subpopulation of LHA glutamatergic neurons but contrasts with a broad population of LHA GABAergic neurons. Identifying the neurochemical diversity of Hcrt/Ox and MCH neurons will further our understanding of how these populations modulate postsynaptic excitability through multiple signaling mechanisms and coordinate diverse behavioral outputs.
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Goforth PB, Myers MG. Roles for Orexin/Hypocretin in the Control of Energy Balance and Metabolism. Curr Top Behav Neurosci 2017; 33:137-156. [PMID: 27909992 DOI: 10.1007/7854_2016_51] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The neuropeptide hypocretin is also commonly referred to as orexin, since its orexigenic action was recognized early. Orexin/hypocretin (OX) neurons project widely throughout the brain and the physiologic and behavioral functions of OX are much more complex than initially conceived based upon the stimulation of feeding. OX most notably controls functions relevant to attention, alertness, and motivation. OX also plays multiple crucial roles in the control of food intake, metabolism, and overall energy balance in mammals. OX signaling not only promotes food-seeking behavior upon short-term fasting to increase food intake and defend body weight, but, conversely, OX signaling also supports energy expenditure to protect against obesity. Furthermore, OX modulates the autonomic nervous system to control glucose metabolism, including during the response to hypoglycemia. Consistently, a variety of nutritional cues (including the hormones leptin and ghrelin) and metabolites (e.g., glucose, amino acids) control OX neurons. In this chapter, we review the control of OX neurons by nutritional/metabolic cues, along with our current understanding of the mechanisms by which OX and OX neurons contribute to the control of energy balance and metabolism.
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Affiliation(s)
- Paulette B Goforth
- Department of Pharmacology, University of Michigan, 1000 Wall St, 5131 Brehm Tower, Ann Arbor, MI, 48105, USA
| | - Martin G Myers
- Departments of Internal Medicine, and Molecular and Integrative Physiology, University of Michigan, 1000 Wall St, 6317 Brehm Tower, Ann Arbor, MI, 48105, USA.
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Tyree SM, de Lecea L. Lateral Hypothalamic Control of the Ventral Tegmental Area: Reward Evaluation and the Driving of Motivated Behavior. Front Syst Neurosci 2017; 11:50. [PMID: 28729827 PMCID: PMC5498520 DOI: 10.3389/fnsys.2017.00050] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/22/2017] [Indexed: 12/25/2022] Open
Abstract
The lateral hypothalamus (LH) plays an important role in many motivated behaviors, sleep-wake states, food intake, drug-seeking, energy balance, etc. It is also home to a heterogeneous population of neurons that express and co-express multiple neuropeptides including hypocretin (Hcrt), melanin-concentrating hormone (MCH), cocaine- and amphetamine-regulated transcript (CART) and neurotensin (NT). These neurons project widely throughout the brain to areas such as the locus coeruleus, the bed nucleus of the stria terminalis, the amygdala and the ventral tegmental area (VTA). Lateral hypothalamic projections to the VTA are believed to be important for driving behavior due to the involvement of dopaminergic reward circuitry. The purpose of this article is to review current knowledge regarding the lateral hypothalamic connections to the VTA and the role they play in driving these behaviors.
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Affiliation(s)
- Susan M Tyree
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford UniversityStanford, CA, United States
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44
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Galanin-Expressing GABA Neurons in the Lateral Hypothalamus Modulate Food Reward and Noncompulsive Locomotion. J Neurosci 2017; 37:6053-6065. [PMID: 28539422 DOI: 10.1523/jneurosci.0155-17.2017] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/26/2017] [Accepted: 05/16/2017] [Indexed: 12/20/2022] Open
Abstract
The lateral hypothalamus (LHA) integrates reward and appetitive behavior and is composed of many overlapping neuronal populations. Recent studies associated LHA GABAergic neurons (LHA GABA ), which densely innervate the ventral tegmental area (VTA), with modulation of food reward and consumption; yet, LHA GABA projections to the VTA exclusively modulated food consumption, not reward. We identified a subpopulation of LHA GABA neurons that coexpress the neuropeptide galanin (LHA Gal ). These LHA Gal neurons also modulate food reward, but lack direct VTA innervation. We hypothesized that LHA Gal neurons may represent a subpopulation of LHA GABA neurons that mediates food reward independent of direct VTA innervation. We used chemogenetic activation of LHA Gal or LHA GABA neurons in mice to compare their role in feeding behavior. We further analyzed locomotor behavior to understand how differential VTA connectivity and transmitter release in these LHA neurons influences this behavior. LHA Gal or LHA GABA neuronal activation both increased operant food-seeking behavior, but only activation of LHA GABA neurons increased overall chow consumption. Additionally, LHA Gal or LHA GABA neuronal activation similarly induced locomotor activity, but with striking differences in modality. Activation of LHA GABA neurons induced compulsive-like locomotor behavior; while LHA Gal neurons induced locomotor activity without compulsivity. Thus, LHA Gal neurons define a subpopulation of LHA GABA neurons without direct VTA innervation that mediate noncompulsive food-seeking behavior. We speculate that the striking difference in compulsive-like locomotor behavior is also based on differential VTA innervation. The downstream neural network responsible for this behavior and a potential role for galanin as neuromodulator remains to be identified.SIGNIFICANCE STATEMENT The lateral hypothalamus (LHA) regulates motivated feeding behavior via GABAergic LHA neurons. The molecular identity of LHA GABA neurons is heterogeneous and largely undefined. Here we introduce LHA Gal neurons as a subset of LHA GABA neurons that lack direct innervation of the ventral tegmental area (VTA). LHA Gal neurons are sufficient to drive motivated feeding and locomotor activity similar to LHA GABA neurons, but without inducing compulsive-like behaviors, which we propose to require direct VTA innervation. Our study integrates galanin-expressing LHA neurons into our current understanding of the neuronal circuits and molecular mechanisms of the LHA that contribute to motivated feeding behaviors.
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Brown JA, Bugescu R, Mayer TA, Gata-Garcia A, Kurt G, Woodworth HL, Leinninger GM. Loss of Action via Neurotensin-Leptin Receptor Neurons Disrupts Leptin and Ghrelin-Mediated Control of Energy Balance. Endocrinology 2017; 158:1271-1288. [PMID: 28323938 PMCID: PMC5460836 DOI: 10.1210/en.2017-00122] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/06/2017] [Indexed: 01/30/2023]
Abstract
The hormones ghrelin and leptin act via the lateral hypothalamic area (LHA) to modify energy balance, but the underlying neural mechanisms remain unclear. We investigated how leptin and ghrelin engage LHA neurons to modify energy balance behaviors and whether there is any crosstalk between leptin and ghrelin-responsive circuits. We demonstrate that ghrelin activates LHA neurons expressing hypocretin/orexin (OX) to increase food intake. Leptin mediates anorectic actions via separate neurons expressing the long form of the leptin receptor (LepRb), many of which coexpress the neuropeptide neurotensin (Nts); we refer to these as NtsLepRb neurons. Because NtsLepRb neurons inhibit OX neurons, we hypothesized that disruption of the NtsLepRb neuronal circuit would impair both NtsLepRb and OX neurons from responding to their respective hormonal cues, thus compromising adaptive energy balance. Indeed, mice with developmental deletion of LepRb specifically from NtsLepRb neurons exhibit blunted adaptive responses to leptin and ghrelin that discoordinate the mesolimbic dopamine system and ingestive and locomotor behaviors, leading to weight gain. Collectively, these data reveal a crucial role for LepRb in the proper formation of LHA circuits, and that NtsLepRb neurons are important neuronal hubs within the LHA for hormone-mediated control of ingestive and locomotor behaviors.
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Affiliation(s)
- Juliette A. Brown
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824
| | - Thomas A. Mayer
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824
| | - Adriana Gata-Garcia
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Gizem Kurt
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824
| | - Hillary L. Woodworth
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824
| | - Gina M. Leinninger
- Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824
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46
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The rostromedial zona incerta is involved in attentional processes while adjacent LHA responds to arousal: c-Fos and anatomical evidence. Brain Struct Funct 2017; 222:2507-2525. [DOI: 10.1007/s00429-016-1353-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 12/16/2016] [Indexed: 01/27/2023]
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Frihauf JB, Fekete ÉM, Nagy TR, Levin BE, Zorrilla EP. Maternal Western diet increases adiposity even in male offspring of obesity-resistant rat dams: early endocrine risk markers. Am J Physiol Regul Integr Comp Physiol 2016; 311:R1045-R1059. [PMID: 27654396 DOI: 10.1152/ajpregu.00023.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 08/30/2016] [Accepted: 09/12/2016] [Indexed: 01/08/2023]
Abstract
Maternal overnutrition or associated complications putatively mediate the obesogenic effects of perinatal high-fat diet on developing offspring. Here, we tested the hypothesis that a Western diet developmental environment increases adiposity not only in male offspring from obesity-prone (DIO) mothers, but also in those from obesity-resistant (DR) dams, implicating a deleterious role for the Western diet per se. Selectively bred DIO and DR female rats were fed chow (17% kcal fat) or Western diet (32%) for 54 days before mating and, thereafter, through weaning. As intended, despite chow-like caloric intake, Western diet increased prepregnancy weight gain and circulating leptin levels in DIO, but not DR, dams. Yet, in both genotypes, maternal Western diet increased the weight and adiposity of preweanlings, as early as in DR offspring, and increased plasma leptin, insulin, and adiponectin of weanlings. Although body weight normalized with chow feeding during adolescence, young adult Western diet offspring subsequently showed decreased energy expenditure and, in DR offspring, decreased lipid utilization as a fuel substrate. By mid-adulthood, maternal Western diet DR offspring ate more chow, weighed more, and were fatter than controls. Thus, maternal Western diet covertly programmed increased adiposity in childhood and adulthood, disrupted relations of energy regulatory hormones with body fat, and decreased energy expenditure in offspring of lean, genetically obesity-resistant mothers. Maternal Western diet exposure alone, without maternal obesity or overnutrition, can promote offspring weight gain.
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Affiliation(s)
- Jennifer B Frihauf
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.,Neurosciences Graduate Program, University of California, San Diego, La Jolla, California
| | - Éva M Fekete
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Tim R Nagy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Barry E Levin
- Neurology Service, VA Medical Center, East Orange, New Jersey; and.,Department of Neurology, Rutgers, New Jersey Medical School, Newark, New Jersey
| | - Eric P Zorrilla
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California; .,Neurosciences Graduate Program, University of California, San Diego, La Jolla, California
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48
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Bonnavion P, Mickelsen LE, Fujita A, de Lecea L, Jackson AC. Hubs and spokes of the lateral hypothalamus: cell types, circuits and behaviour. J Physiol 2016; 594:6443-6462. [PMID: 27302606 DOI: 10.1113/jp271946] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022] Open
Abstract
The hypothalamus is among the most phylogenetically conserved regions in the vertebrate brain, reflecting its critical role in maintaining physiological and behavioural homeostasis. By integrating signals arising from both the brain and periphery, it governs a litany of behaviourally important functions essential for survival. In particular, the lateral hypothalamic area (LHA) is central to the orchestration of sleep-wake states, feeding, energy balance and motivated behaviour. Underlying these diverse functions is a heterogeneous assembly of cell populations typically defined by neurochemical markers, such as the well-described neuropeptides hypocretin/orexin and melanin-concentrating hormone. However, anatomical and functional evidence suggests a rich diversity of other cell populations with complex neurochemical profiles that include neuropeptides, receptors and components of fast neurotransmission. Collectively, the LHA acts as a hub for the integration of diverse central and peripheral signals and, through complex local and long-range output circuits, coordinates adaptive behavioural responses to the environment. Despite tremendous progress in our understanding of the LHA, defining the identity of functionally discrete LHA cell types, and their roles in driving complex behaviour, remain significant challenges in the field. In this review, we discuss advances in our understanding of the neurochemical and cellular heterogeneity of LHA neurons and the recent application of powerful new techniques, such as opto- and chemogenetics, in defining the role of LHA circuits in feeding, reward, arousal and stress. From pioneering work to recent developments, we review how the interrogation of LHA cells and circuits is contributing to a mechanistic understanding of how the LHA coordinates complex behaviour.
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Affiliation(s)
- Patricia Bonnavion
- Laboratory of Neurophysiology, Université Libre de Bruxelles (ULB)-UNI, 1050, Brussels, Belgium
| | - Laura E Mickelsen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Akie Fujita
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
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Otgon-Uul Z, Suyama S, Onodera H, Yada T. Optogenetic activation of leptin- and glucose-regulated GABAergic neurons in dorsomedial hypothalamus promotes food intake via inhibitory synaptic transmission to paraventricular nucleus of hypothalamus. Mol Metab 2016; 5:709-715. [PMID: 27656408 PMCID: PMC5021668 DOI: 10.1016/j.molmet.2016.06.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE The dorsomedial hypothalamus (DMH) has been considered an orexigenic nucleus, since the DMH lesion reduced food intake and body weight and induced resistance to diet-induced obesity. The DMH expresses feeding regulatory neuropeptides and receptors including neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART), cholecystokinin (CCK), leptin receptor, and melanocortin 3/4 receptors. However, the principal neurons generating the orexigenic function in the DMH remain to be defined. This study aimed to clarify the role of the DMH GABAergic neurons in feeding regulation by using optogenetics and electrophysiological techniques. METHODS We generated the mice expressing ChRFR-C167A, a bistable chimeric channelrhodopsin, selectively in GABAergic neurons of DMH via locally injected adeno-associated virus 2. Food intake after optogenetic activation of DMH GABAergic neurons was measured. Electrophysiological properties of DMH GABAergic neurons were measured using slice patch clamp. RESULTS Optogenetic activation of DMH GABAergic neurons promoted food intake. Leptin hyperpolarized and lowering glucose depolarized half of DMH GABAergic neurons, suggesting their orexigenic property. Optical activation of axonal terminals of DMH GABAergic neurons at the paraventricular nucleus of hypothalamus (PVN), where anorexigenic neurons are localized, increased inhibitory postsynaptic currents on PVN neurons and promoted food intake. CONCLUSION DMH GABAergic neurons are regulated by metabolic signals leptin and glucose and, once activated, promote food intake via inhibitory synaptic transmission to PVN.
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Affiliation(s)
- Zesemdorj Otgon-Uul
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan
| | - Shigetomo Suyama
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan
| | - Hiroshi Onodera
- Photon Science Center of the University of Tokyo, Department of Electrical Engineering of the University of Tokyo, Tokyo, Japan
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan.
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50
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Yao Q, Pho H, Kirkness J, Ladenheim EE, Bi S, Moran TH, Fuller DD, Schwartz AR, Polotsky VY. Localizing Effects of Leptin on Upper Airway and Respiratory Control during Sleep. Sleep 2016; 39:1097-106. [PMID: 26951402 DOI: 10.5665/sleep.5762] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/01/2016] [Indexed: 12/30/2022] Open
Abstract
STUDY OBJECTIVES Obesity hypoventilation and obstructive sleep apnea are common complications of obesity linked to defects in respiratory pump and upper airway neural control. Leptin-deficient ob/ob mice have impaired ventilatory control and inspiratory flow limitation during sleep, which are both reversed with leptin. We aimed to localize central nervous system (CNS) site(s) of leptin action on respiratory and upper airway neuroventilatory control. METHODS We localized the effect of leptin to medulla versus hypothalamus by administering intracerbroventricular leptin (10 μg/2 μL) versus vehicle to the lateral (n = 14) versus fourth ventricle (n = 11) of ob/ob mice followed by polysomnographic recording. Analyses were stratified for effects on respiratory (nonflow-limited breaths) and upper airway (inspiratory flow limitation) functions. CNS loci were identified by (1) leptin-induced signal transducer and activator of transcription 3 (STAT3) phosphorylation and (2) projections of respiratory and upper airway motoneurons with a retrograde transsynaptic tracer (pseudorabies virus). RESULTS Both routes of leptin administration increased minute ventilation during nonflow-limited breathing in sleep. Phrenic motoneurons were synaptically coupled to the nucleus of the solitary tract, which also showed STAT3 phosphorylation, but not to the hypothalamus. Inspiratory flow limitation and obstructive hypopneas were attenuated by leptin administration to the lateral but not to the fourth cerebral ventricle. Upper airway motoneurons were synaptically coupled with the dorsomedial hypothalamus, which exhibited STAT3 phosphorylation. CONCLUSIONS Leptin relieves upper airway obstruction in sleep apnea by activating the forebrain, possibly in the dorsomedial hypothalamus. In contrast, leptin upregulates ventilatory control through hindbrain sites of action, possibly in the nucleus of the solitary tract.
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Affiliation(s)
- Qiaoling Yao
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Physiology; Preclinical School, Xinjiang Medical University, Xinjiang, China
| | - Huy Pho
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jason Kirkness
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ellen E Ladenheim
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Sheng Bi
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Timothy H Moran
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - David D Fuller
- Departments of Physical Therapy, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
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