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Brown JM, Bentsen MA, Rausch DM, Phan BA, Wieck D, Wasanwala H, Matsen ME, Acharya N, Richardson NE, Zhao X, Zhai P, Secher A, Morton GJ, Pers TH, Schwartz MW, Scarlett JM. Role of hypothalamic MAPK/ERK signaling and central action of FGF1 in diabetes remission. iScience 2021; 24:102944. [PMID: 34430821 PMCID: PMC8368994 DOI: 10.1016/j.isci.2021.102944] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/28/2021] [Accepted: 07/30/2021] [Indexed: 12/13/2022] Open
Abstract
The capacity of the brain to elicit sustained remission of hyperglycemia in rodent models of type 2 diabetes following intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) is well established. Here, we show that following icv FGF1 injection, hypothalamic signaling by extracellular signal-regulated kinases 1 and 2 (ERK1/2), members of the mitogen-activated protein kinase (MAPK) family, is induced for at least 24 h. Further, we show that this prolonged response is required for the sustained antidiabetic action of FGF1 since it is abolished by sustained (but not acute) pharmacologic blockade of hypothalamic MAPK/ERK signaling. We also demonstrate that FGF1 R50E, a FGF1 mutant that activates FGF receptors but induces only transient hypothalamic MAPK/ERK signaling, fails to mimic the sustained glucose lowering induced by FGF1. These data identify sustained activation of hypothalamic MAPK/ERK signaling as playing an essential role in the mechanism underlying diabetes remission induced by icv FGF1 administration. FGF1 action in the brain induces remission of diabetic hyperglycemia FGF1 induces sustained activation of hypothalamic MAPK/ERK signaling Blockade of hypothalamic MAPK/ERK signaling abolishes the antidiabetic action of FGF1 FGF1 increases hypothalamic astrocyte-neuron interaction by transcriptomic analysis
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Affiliation(s)
- Jenny M Brown
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA.,Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Marie A Bentsen
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA.,Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Dylan M Rausch
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Bao Anh Phan
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Danielle Wieck
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Huzaifa Wasanwala
- Department of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Miles E Matsen
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Nikhil Acharya
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Nicole E Richardson
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Xin Zhao
- Global Drug Discovery, Novo Nordisk Research China, Beijing 102206, China
| | - Peng Zhai
- Global Drug Discovery, Novo Nordisk Research China, Beijing 102206, China
| | - Anna Secher
- Global Drug Discovery, Novo Nordisk A/S, 2760 Maaloev, Denmark
| | - Gregory J Morton
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Tune H Pers
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Michael W Schwartz
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA
| | - Jarrad M Scarlett
- Department of Medicine, University of Washington Medicine Diabetes Institute, 750 Republican St, F770, Seattle, WA 98109, USA.,Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA 98145, USA
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Brown JM, Scarlett JM, Matsen ME, Nguyen HT, Secher A, Jorgensen R, Morton GJ, Schwartz MW. Erratum. The Hypothalamic Arcuate Nucleus-Median Eminence Is a Target for Sustained Diabetes Remission Induced by Fibroblast Growth Factor 1. Diabetes 2019;68:1054-1061. Diabetes 2021; 70:817. [PMID: 33355215 PMCID: PMC7897344 DOI: 10.2337/db21-er03a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Stereotactic surgery is an essential tool in the modern neuroscience lab. However, the ability to precisely and accurately target difficult-to-reach brain regions still presents a challenge, particularly when targeting brain structures along the midline. These challenges include avoiding of the superior sagittal sinus and third ventricle and the ability to consistently target selective and discrete brain nuclei. In addition, more advanced neuroscience techniques (e.g., optogenetics, fiber photometry, and two-photon imaging) rely on targeted implantation of significant hardware to the brain, and spatial limitations are a common hindrance. Presented here is a modifiable protocol for stereotactic targeting of rodent brain structures using an angled coronal approach. It can be adapted to 1) mouse or rat models, 2) various neuroscience techniques, and 3) multiple brain regions. As a representative example, it includes the calculation of stereotactic coordinates for targeting of the mouse hypothalamic ventromedial nucleus (VMN) for an optogenetic inhibition experiment. This procedure begins with the bilateral microinjection of an adeno-associated virus (AAV) encoding a light-sensitive chloride channel (SwiChR++) to a Cre-dependent mouse model, followed by the angled bilateral implantation of fiberoptic cannulae. Using this approach, findings show that activation of a subset of VMN neurons is required for intact glucose counterregulatory responses to insulin-induced hypoglycemia.
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Brown JM, Scarlett JM, Matsen ME, Nguyen HT, Secher A, Jorgensen R, Morton GJ, Schwartz MW. The Hypothalamic Arcuate Nucleus-Median Eminence Is a Target for Sustained Diabetes Remission Induced by Fibroblast Growth Factor 1. Diabetes 2019; 68:1054-1061. [PMID: 30796029 PMCID: PMC6477902 DOI: 10.2337/db19-0025] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/14/2019] [Indexed: 12/13/2022]
Abstract
In rodent models of type 2 diabetes (T2D), sustained remission of diabetic hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1). To identify the brain areas responsible for this effect, we first used immunohistochemistry to map the hypothalamic distribution of phosphorylated extracellular signal-related kinase 1/2 (pERK1/2), a marker of mitogen-activated protein kinase-ERK signal transduction downstream of FGF receptor activation. Twenty minutes after icv FGF1 injection in adult male Wistar rats, pERK1/2 staining was detected primarily in two hypothalamic areas: the arcuate nucleus-median eminence (ARC-ME) and the paraventricular nucleus (PVN). To determine whether an action of FGF1 localized to either the ARC-ME or the PVN is capable of mimicking the sustained antidiabetic effect elicited by icv FGF1, we microinjected either saline vehicle or a low dose of FGF1 (0.3 µg/side) bilaterally into either the ARC-ME area or PVN of Zucker Diabetic Fatty rats, a model of T2D, and monitored daily food intake, body weight, and blood glucose levels over a 3-week period. Whereas bilateral intra-arcuate microinjection of saline vehicle was without effect, remission of hyperglycemia lasting >3 weeks was observed following bilateral microinjection of FGF1 into the ARC-ME. This antidiabetic effect cannot be attributed to leakage of FGF1 into cerebrospinal fluid and subsequent action on other brain areas, since icv injection of the same total dose was without effect. Combined with our finding that bilateral microinjection of the same dose of FGF1 into the PVN was without effect on glycemia or other parameters, we conclude that the ARC-ME area (but not the PVN) is a target for sustained remission of diabetic hyperglycemia induced by FGF1.
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Affiliation(s)
- Jenny M Brown
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Jarrad M Scarlett
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Pediatric Gastroenterology and Hepatology, University of Washington, Seattle, WA
| | - Miles E Matsen
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Hong T Nguyen
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Anna Secher
- Diabetes Research, Global Drug Discovery, Novo Nordisk, Måløv, Denmark
| | - Rasmus Jorgensen
- Diabetes Research, Global Drug Discovery, Novo Nordisk, Måløv, Denmark
| | - Gregory J Morton
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
| | - Michael W Schwartz
- Department of Medicine, UW Medicine Diabetes Institute, University of Washington, Seattle, WA
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Scarlett JM, Muta K, Brown JM, Rojas JM, Matsen ME, Acharya NK, Secher A, Ingvorsen C, Jorgensen R, Høeg-Jensen T, Stefanovski D, Bergman RN, Piccinini F, Kaiyala KJ, Shiota M, Morton GJ, Schwartz MW. Peripheral Mechanisms Mediating the Sustained Antidiabetic Action of FGF1 in the Brain. Diabetes 2019; 68:654-664. [PMID: 30523024 PMCID: PMC6385755 DOI: 10.2337/db18-0498] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/29/2018] [Indexed: 12/24/2022]
Abstract
We recently reported that in rodent models of type 2 diabetes (T2D), a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) induces remission of hyperglycemia that is sustained for weeks. To clarify the peripheral mechanisms underlying this effect, we used the Zucker diabetic fatty fa/fa rat model of T2D, which, like human T2D, is characterized by progressive deterioration of pancreatic β-cell function after hyperglycemia onset. We report that although icv FGF1 injection delays the onset of β-cell dysfunction in these animals, it has no effect on either glucose-induced insulin secretion or insulin sensitivity. These observations suggest that FGF1 acts in the brain to stimulate insulin-independent glucose clearance. On the basis of our finding that icv FGF1 treatment increases hepatic glucokinase gene expression, we considered the possibility that increased hepatic glucose uptake (HGU) contributes to the insulin-independent glucose-lowering effect of icv FGF1. Consistent with this possibility, we report that icv FGF1 injection increases liver glucokinase activity by approximately twofold. We conclude that sustained remission of hyperglycemia induced by the central action of FGF1 involves both preservation of β-cell function and stimulation of HGU through increased hepatic glucokinase activity.
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Affiliation(s)
- Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
- Gastroenterology and Hepatology, Department of Pediatrics, University of Washington, Seattle, WA
| | - Kenjiro Muta
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jenny M Brown
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jennifer M Rojas
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
- Department of Physiology, Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Miles E Matsen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Nikhil K Acharya
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | | | | | | | | | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Francesca Piccinini
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Gregory J Morton
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Michael W Schwartz
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
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Mirzadeh Z, Alonge KM, Cabrales E, Herranz-Pérez V, Scarlett JM, Brown JM, Hassouna R, Matsen ME, Nguyen HT, Garcia-Verdugo JM, Zeltser LM, Schwartz MW. Perineuronal Net Formation during the Critical Period for Neuronal Maturation in the Hypothalamic Arcuate Nucleus. Nat Metab 2019; 1:212-221. [PMID: 31245789 PMCID: PMC6594569 DOI: 10.1038/s42255-018-0029-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In leptin-deficient ob/ob mice, obesity and diabetes are associated with abnormal development of neurocircuits in the hypothalamic arcuate nucleus (ARC)1, a critical brain area for energy and glucose homeostasis2,3. As this developmental defect can be remedied by systemic leptin administration, but only if given before postnatal day 28, a critical period (CP) for leptin-dependent development of ARC neurocircuits has been proposed4. In other brain areas, CP closure coincides with the appearance of perineuronal nets (PNNs), extracellular matrix specializations that restrict the plasticity of neurons that they enmesh5. Here we report that in humans as well as rodents, subsets of neurons in the mediobasal aspect of the ARC are enmeshed by PNN-like structures. In mice, these neurons are densely-packed into a continuous ring that encircles the junction of the ARC and median eminence, which facilitates exposure of ARC neurons to the circulation. Most of the enmeshed neurons are both GABAergic and leptin receptor-positive, including a majority of Agrp neurons. Postnatal formation of the PNN-like structures coincides precisely with closure of the CP for Agrp neuron maturation and is dependent on input from circulating leptin, as postnatal ob/ob mice have reduced ARC PNN-like material that is restored by leptin administration during the CP. We conclude that neurons crucial to metabolic homeostasis are enmeshed by PNN-like structures and organized into a densely packed cluster situated circumferentially at the ARC-ME junction, where metabolically-relevant humoral signals are sensed.
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Affiliation(s)
- Zaman Mirzadeh
- Department of Neurosurgery, Barrow Neurological Institute, Phoenix, AZ, USA.
| | - Kimberly M Alonge
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA
| | - Elaine Cabrales
- Department of Neurosurgery, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Vicente Herranz-Pérez
- Laboratory of Comparative Neurobiology, Instituto Cavanilles, CIBERNED, Universidad de Valencia, Valencia, Spain
- Predepartmental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, Castellón de la Plana, Spain
| | - Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA, USA
| | - Jenny M Brown
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA
| | - Rim Hassouna
- Naomi Berrie Diabetes Center, Columbia University Medical Center, New York, NY, USA
| | - Miles E Matsen
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA
| | - Hong T Nguyen
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA
| | - Jose Manuel Garcia-Verdugo
- Laboratory of Comparative Neurobiology, Instituto Cavanilles, CIBERNED, Universidad de Valencia, Valencia, Spain
| | - Lori M Zeltser
- Naomi Berrie Diabetes Center, Columbia University Medical Center, New York, NY, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Michael W Schwartz
- University of Washington Medicine Diabetes Institute, School of Medicine, University of Washington, Seattle, WA, USA.
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Muta K, Matsen ME, Acharya NK, Stefanovski D, Bergman RN, Schwartz MW, Morton GJ. Glucoregulatory responses to hypothalamic preoptic area cooling. Brain Res 2019; 1710:136-145. [PMID: 30610874 DOI: 10.1016/j.brainres.2019.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/21/2018] [Accepted: 01/01/2019] [Indexed: 11/26/2022]
Abstract
Normal glucose homeostasis depends on the capacity of pancreatic β-cells to adjust insulin secretion in response to a change of tissue insulin sensitivity. In cold environments, for example, the dramatic increase of insulin sensitivity required to ensure a sufficient supply of glucose to thermogenic tissues is offset by a proportionate reduction of insulin secretion, such that overall glucose tolerance is preserved. That these cold-induced changes of insulin secretion and insulin sensitivity are dependent on sympathetic nervous system (SNS) outflow suggests a key role for thermoregulatory neurons in the hypothalamic preoptic area (POA) in this metabolic response. As these POA neurons are themselves sensitive to changes in local hypothalamic temperature, we hypothesized that direct cooling of the POA would elicit the same glucoregulatory responses that we observed during cold exposure. To test this hypothesis, we used a thermode to cool the POA area, and found that as predicted, short-term (8-h) intense POA cooling reduced glucose-stimulated insulin secretion (GSIS), yet glucose tolerance remained unchanged due to an increase of insulin sensitivity. Longer-term (24-h), more moderate POA cooling, however, failed to inhibit GSIS and improved glucose tolerance, an effect associated with hyperthermia and activation of the hypothalamic-pituitary-adrenal axis, indicative of a stress response. Taken together, these findings suggest that POA cooling is sufficient to recapitulate key glucoregulatory responses to cold exposure.
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Affiliation(s)
- Kenjiro Muta
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Miles E Matsen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Nikhil K Acharya
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Michael W Schwartz
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Gregory J Morton
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA, USA.
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Faber CL, Matsen ME, Velasco KR, Damian V, Phan BA, Adam D, Therattil A, Schwartz MW, Morton GJ. Distinct Neuronal Projections From the Hypothalamic Ventromedial Nucleus Mediate Glycemic and Behavioral Effects. Diabetes 2018; 67:2518-2529. [PMID: 30257978 PMCID: PMC6245222 DOI: 10.2337/db18-0380] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/17/2018] [Indexed: 01/03/2023]
Abstract
The hypothalamic ventromedial nucleus (VMN) is implicated both in autonomic control of blood glucose and in behaviors including fear and aggression, but whether these divergent effects involve the same or distinct neuronal subsets and their projections is unknown. To address this question, we used an optogenetic approach to selectively activate the subset of VMN neurons that express neuronal nitric oxide synthase 1 (VMNNOS1 neurons) implicated in glucose counterregulation. We found that photoactivation of these neurons elicits 1) robust hyperglycemia achieved by activation of counterregulatory responses usually reserved for the physiological response to hypoglycemia and 2) defensive immobility behavior. Moreover, we show that the glucagon, but not corticosterone, response to insulin-induced hypoglycemia is blunted by photoinhibition of the same neurons. To investigate the neurocircuitry by which VMNNOS1 neurons mediate these effects, and to determine whether these diverse effects are dissociable from one another, we activated downstream VMNNOS1 projections in either the anterior bed nucleus of the stria terminalis (aBNST) or the periaqueductal gray (PAG). Whereas glycemic responses are fully recapitulated by activation of VMNNOS1 projections to the aBNST, freezing immobility occurred only upon activation of VMNNOS1 terminals in the PAG. These findings support previous evidence of a VMN→aBNST neurocircuit involved in glucose counterregulation and demonstrate that activation of VMNNOS1 neuronal projections supplying the PAG robustly elicits defensive behaviors.
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Affiliation(s)
- Chelsea L Faber
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Miles E Matsen
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Kevin R Velasco
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Vincent Damian
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Bao Anh Phan
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Daniel Adam
- School of Medicine, Creighton University, Omaha, NE
| | | | - Michael W Schwartz
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Gregory J Morton
- UW Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
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Meek TH, Matsen ME, Faber CL, Samstag CL, Damian V, Nguyen HT, Scarlett JM, Flak JN, Myers MG, Morton GJ. In Uncontrolled Diabetes, Hyperglucagonemia and Ketosis Result From Deficient Leptin Action in the Parabrachial Nucleus. Endocrinology 2018; 159:1585-1594. [PMID: 29438473 PMCID: PMC5939636 DOI: 10.1210/en.2017-03199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022]
Abstract
Growing evidence implicates neurons that project from the lateral parabrachial nucleus (LPBN) to the hypothalamic ventromedial nucleus (VMN) in a neurocircuit that drives counterregulatory responses to hypoglycemia, including increased glucagon secretion. Among LPBN neurons in this circuit is a subset that expresses cholecystokinin (LPBNCCK neurons) and is tonically inhibited by leptin. Because uncontrolled diabetes is associated with both leptin deficiency and hyperglucagonemia, and because intracerebroventricular (ICV) leptin administration reverses both hyperglycemia and hyperglucagonemia in this setting, we hypothesized that deficient leptin inhibition of LPBNCCK neurons drives activation of this LPBN→VMN circuit and thereby results in hyperglucagonemia. Here, we report that although bilateral microinjection of leptin into the LPBN does not ameliorate hyperglycemia in rats with streptozotocin-induced diabetes mellitus (STZ-DM), it does attenuate the associated hyperglucagonemia and ketosis. To determine if LPBN leptin signaling is required for the antidiabetic effect of ICV leptin in STZ-DM, we studied mice in which the leptin receptor was selectively deleted from LPBNCCK neurons. Our findings show that although leptin signaling in these neurons is not required for the potent antidiabetic effect of ICV leptin, it is required for leptin-mediated suppression of diabetic hyperglucagonemia. Taken together, these findings suggest that leptin-mediated effects in animals with uncontrolled diabetes occur through actions involving multiple brain areas, including the LPBN, where leptin acts specifically to inhibit glucagon secretion and associated ketosis.
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Affiliation(s)
- Thomas H Meek
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Miles E Matsen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Chelsea L Faber
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Colby L Samstag
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Vincent Damian
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Hong T Nguyen
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
| | - Jonathan N Flak
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Martin G Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Gregory J Morton
- University of Washington Medicine Diabetes Institute, Department of Medicine, University of Washington, Seattle, Washington
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10
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Roberts ZS, Wolden-Hanson T, Matsen ME, Ryu V, Vaughan CH, Graham JL, Havel PJ, Chukri DW, Schwartz MW, Morton GJ, Blevins JE. Chronic hindbrain administration of oxytocin is sufficient to elicit weight loss in diet-induced obese rats. Am J Physiol Regul Integr Comp Physiol 2017; 313:R357-R371. [PMID: 28747407 DOI: 10.1152/ajpregu.00169.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 02/06/2023]
Abstract
Oxytocin (OT) administration elicits weight loss in diet-induced obese (DIO) rodents, nonhuman primates, and humans by reducing energy intake and increasing energy expenditure. Although the neurocircuitry underlying these effects remains uncertain, OT neurons in the paraventricular nucleus are positioned to control both energy intake and sympathetic nervous system outflow to interscapular brown adipose tissue (BAT) through projections to the hindbrain nucleus of the solitary tract and spinal cord. The current work was undertaken to examine whether central OT increases BAT thermogenesis, whether this effect involves hindbrain OT receptors (OTRs), and whether such effects are associated with sustained weight loss following chronic administration. To assess OT-elicited changes in BAT thermogenesis, we measured the effects of intracerebroventricular administration of OT on interscapular BAT temperature in rats and mice. Because fourth ventricular (4V) infusion targets hindbrain OTRs, whereas third ventricular (3V) administration targets both forebrain and hindbrain OTRs, we compared responses to OT following chronic 3V infusion in DIO rats and mice and chronic 4V infusion in DIO rats. We report that chronic 4V infusion of OT into two distinct rat models recapitulates the effects of 3V OT to ameliorate DIO by reducing fat mass. While reduced food intake contributes to this effect, our finding that 4V OT also increases BAT thermogenesis suggests that increased energy expenditure may contribute as well. Collectively, these findings support the hypothesis that, in DIO rats, OT action in the hindbrain evokes sustained weight loss by reducing energy intake and increasing BAT thermogenesis.
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Affiliation(s)
- Zachary S Roberts
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Tami Wolden-Hanson
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Miles E Matsen
- University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - Vitaly Ryu
- Department of Biology, Georgia State University, Atlanta, Georgia; and.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia
| | - Cheryl H Vaughan
- Department of Biology, Georgia State University, Atlanta, Georgia; and.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia
| | - James L Graham
- Departments of Nutrition and Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Peter J Havel
- Departments of Nutrition and Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Daniel W Chukri
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington.,University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - Gregory J Morton
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington.,University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - James E Blevins
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; .,Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
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11
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Morton GJ, Muta K, Kaiyala KJ, Rojas JM, Scarlett JM, Matsen ME, Nelson JT, Acharya NK, Piccinini F, Stefanovski D, Bergman RN, Taborsky GJ, Kahn SE, Schwartz MW. Evidence That the Sympathetic Nervous System Elicits Rapid, Coordinated, and Reciprocal Adjustments of Insulin Secretion and Insulin Sensitivity During Cold Exposure. Diabetes 2017; 66:823-834. [PMID: 28115396 PMCID: PMC5360298 DOI: 10.2337/db16-1351] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 01/03/2017] [Indexed: 12/21/2022]
Abstract
Dynamic adjustment of insulin secretion to compensate for changes of insulin sensitivity that result from alteration of nutritional or metabolic status is a fundamental aspect of glucose homeostasis. To investigate the role of the brain in this coupling process, we used cold exposure as an experimental paradigm because the sympathetic nervous system (SNS) helps to coordinate the major shifts of tissue glucose utilization needed to ensure that increased thermogenic needs are met. We found that glucose-induced insulin secretion declined by 50% in rats housed at 5°C for 28 h, and yet, glucose tolerance did not change, owing to a doubling of insulin sensitivity. These potent effects on insulin secretion and sensitivity were fully reversed by returning animals to room temperature (22°C) for 4 h or by intravenous infusion of the α-adrenergic receptor antagonist phentolamine for only 30 min. By comparison, insulin clearance was not affected by cold exposure or phentolamine infusion. These findings offer direct evidence of a key role for the brain, acting via the SNS, in the rapid, highly coordinated, and reciprocal changes of insulin secretion and insulin sensitivity that preserve glucose homeostasis in the setting of cold exposure.
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Affiliation(s)
- Gregory J Morton
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Kenjiro Muta
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA
| | - Jennifer M Rojas
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jarrad M Scarlett
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
- Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA
| | - Miles E Matsen
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Jarrell T Nelson
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Nikhil K Acharya
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
| | - Francesca Piccinini
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Gerald J Taborsky
- Veterans Affairs Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, WA
| | - Steven E Kahn
- Veterans Affairs Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, WA
| | - Michael W Schwartz
- University of Washington Diabetes Institute, Department of Medicine, University of Washington, Seattle, WA
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12
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Dorfman MD, Krull JE, Douglass JD, Fasnacht R, Lara-Lince F, Meek TH, Shi X, Damian V, Nguyen HT, Matsen ME, Morton GJ, Thaler JP. Sex differences in microglial CX3CR1 signalling determine obesity susceptibility in mice. Nat Commun 2017; 8:14556. [PMID: 28223698 PMCID: PMC5322503 DOI: 10.1038/ncomms14556] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 01/12/2017] [Indexed: 02/06/2023] Open
Abstract
Female mice are less susceptible to the negative metabolic consequences of high-fat diet feeding than male mice, for reasons that are incompletely understood. Here we identify sex-specific differences in hypothalamic microglial activation via the CX3CL1-CX3CR1 pathway that mediate the resistance of female mice to diet-induced obesity. Female mice fed a high-fat diet maintain CX3CL1-CX3CR1 levels while male mice show reductions in both ligand and receptor expression. Female Cx3cr1 knockout mice develop 'male-like' hypothalamic microglial accumulation and activation, accompanied by a marked increase in their susceptibility to diet-induced obesity. Conversely, increasing brain CX3CL1 levels in male mice through central pharmacological administration or virally mediated hypothalamic overexpression converts them to a 'female-like' metabolic phenotype with reduced microglial activation and body-weight gain. These data implicate sex differences in microglial activation in the modulation of energy homeostasis and identify CX3CR1 signalling as a potential therapeutic target for the treatment of obesity.
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Affiliation(s)
- Mauricio D. Dorfman
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Jordan E. Krull
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - John D. Douglass
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Rachael Fasnacht
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Fernando Lara-Lince
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Thomas H. Meek
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Xiaogang Shi
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Vincent Damian
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Hong T. Nguyen
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Miles E. Matsen
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Gregory J. Morton
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Joshua P. Thaler
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, Washington 98109, USA
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13
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Morton GJ, Meek TH, Matsen ME, Schwartz MW. Evidence against hypothalamic-pituitary-adrenal axis suppression in the antidiabetic action of leptin. J Clin Invest 2015; 125:4587-91. [PMID: 26529250 DOI: 10.1172/jci82723] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/28/2015] [Indexed: 12/11/2022] Open
Abstract
Leptin administration restores euglycemia in rodents with severe insulin-deficient diabetes, and recent studies to explain this phenomenon have focused on the ability of leptin to normalize excessive hypothalamic-pituitary-adrenal (HPA) axis activity. Here, we employed a streptozotocin-induced rat model (STZ-DM) of uncontrolled insulin-deficient diabetes mellitus (uDM) to investigate the contribution of HPA axis suppression to leptin-mediated glucose lowering. Specifically, we asked if HPA axis activation is required for diabetic hyperglycemia, whether HPA axis normalization can be achieved using a dose of leptin below that needed to normalize glycemia, and if the ability of leptin to lower plasma glucocorticoid levels is required for its antidiabetic action. In STZ-DM rats, neither adrenalectomy-induced (ADX-induced) glucocorticoid deficiency nor pharmacological glucocorticoid receptor blockade lowered elevated blood glucose levels. Although elevated plasma levels of corticosterone were normalized by i.v. leptin infusion at a dose that raises low plasma levels into the physiological range, diabetic hyperglycemia was not altered. Lastly, the potent glucose-lowering effect of continuous intracerebroventricular leptin infusion was not impacted by systemic administration of corticosterone at a dose that maintained elevated plasma levels characteristic of STZ-DM. We conclude that, although restoring low plasma leptin levels into the physiological range effectively normalizes increased HPA axis activity in rats with uDM, this effect is neither necessary nor sufficient to explain leptin's antidiabetic action.
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14
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Meek TH, Dorfman MD, Matsen ME, Fischer JD, Cubelo A, Kumar MR, Taborsky GJ, Morton GJ. Evidence That in Uncontrolled Diabetes, Hyperglucagonemia Is Required for Ketosis but Not for Increased Hepatic Glucose Production or Hyperglycemia. Diabetes 2015; 64:2376-87. [PMID: 25633417 PMCID: PMC4477352 DOI: 10.2337/db14-1562] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/24/2015] [Indexed: 12/16/2022]
Abstract
Several lines of evidence implicate excess glucagon secretion in the elevated rates of hepatic glucose production (HGP), hyperglycemia, and ketosis characteristic of uncontrolled insulin-deficient diabetes (uDM), but whether hyperglucagonemia is required for hyperglycemia in this setting is unknown. To address this question, adult male Wistar rats received either streptozotocin (STZ) to induce uDM (STZ-DM) or vehicle and remained nondiabetic. Four days later, animals received daily subcutaneous injections of either the synthetic GLP-1 receptor agonist liraglutide in a dose-escalating regimen to reverse hyperglucagonemia or its vehicle for 10 days. As expected, plasma glucagon levels were elevated in STZ-DM rats, and although liraglutide treatment lowered glucagon levels to those of nondiabetic controls, it failed to attenuate diabetic hyperglycemia, elevated rates of glucose appearance (Ra), or increased hepatic gluconeogenic gene expression. In contrast, it markedly reduced levels of both plasma ketone bodies and hepatic expression of the rate-limiting enzyme involved in ketone body production. To independently confirm this finding, in a separate study, treatment of STZ-DM rats with a glucagon-neutralizing antibody was sufficient to potently lower plasma ketone bodies but failed to normalize elevated levels of either blood glucose or Ra. These data suggest that in rats with uDM, hyperglucagonemia is required for ketosis but not for increased HGP or hyperglycemia.
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Affiliation(s)
- Thomas H Meek
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
| | - Mauricio D Dorfman
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
| | - Miles E Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
| | - Jonathan D Fischer
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
| | - Alexis Cubelo
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
| | - Monica R Kumar
- University of South Alabama College of Medicine, Mobile, AL
| | - Gerald J Taborsky
- VA Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, WA
| | - Gregory J Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA
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15
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Rojas JM, Matsen ME, Mundinger TO, Morton GJ, Stefanovski D, Bergman RN, Kaiyala KJ, Taborsky GJ, Schwartz MW. Glucose intolerance induced by blockade of central FGF receptors is linked to an acute stress response. Mol Metab 2015; 4:561-8. [PMID: 26266088 PMCID: PMC4529498 DOI: 10.1016/j.molmet.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 05/22/2015] [Accepted: 05/27/2015] [Indexed: 01/19/2023] Open
Abstract
Objective Central administration of ligands for fibroblast growth factor receptors (FGFRs) such as fibroblast growth factor-19 (FGF19) and FGF21 exert glucose-lowering effects in rodent models of obesity and type 2 diabetes (T2D). Conversely, intracerebroventricular (icv) administration of the non-selective FGFR inhibitor (FGFRi) PD173074 causes glucose intolerance, implying a physiological role for neuronal FGFR signaling in glucose homeostasis. The current studies were undertaken to identify neuroendocrine mechanisms underlying the glucose intolerance induced by pharmacological blockade of central FGFRs. Methods Overnight fasted, lean, male, Long-Evans rats received icv injections of either PD173074 or vehicle (Veh) followed 30 min later by performance of a frequently sampled intravenous glucose tolerance test (FSIGT). Minimal model analysis of glucose and insulin data from the FSIGT was performed to estimate insulin-dependent and insulin-independent components of glucose disposal. Plasma levels of lactate, glucagon, corticosterone, non-esterified free fatty acids (NEFA) and catecholamines were measured before and after intravenous (iv) glucose injection. Results Within 20 min of icv PD173074 injection (prior to the FSIGT), plasma levels of lactate, norepinephrine and epinephrine increased markedly, and each returned to baseline rapidly (within 8 min) following the iv glucose bolus. In contrast, plasma glucagon levels were not altered by icv FGFRi at either time point. Consistent with a previous report, glucose tolerance was impaired following icv PD173074 compared to Veh injection and, based on minimal model analysis of FSIGT data, this effect was attributable to reductions of both insulin secretion and the basal insulin effect (BIE), consistent with the inhibitory effect of catecholamines on pancreatic β-cell secretion. By comparison, there were no changes in glucose effectiveness at zero insulin (GEZI) or the insulin sensitivity index (SI). To determine if iv glucose (given during the FSIGT) contributed to the rapid resolution of the sympathoadrenal response induced by icv FGFRi, we performed an additional study comparing groups that received iv saline or iv glucose 30 min after icv FGFRi. Our finding that elevated plasma catecholamine levels returned rapidly to baseline irrespective of whether rats subsequently received an iv bolus of saline or glucose indicates that the rapid reversal of sympathoadrenal activation following icv FGFRi was unrelated to the subsequent glucose bolus. Conclusions The effect of acute inhibition of central FGFR signaling to impair glucose tolerance likely involves a stress response associated with pronounced, but transient, sympathoadrenal activation and an associated reduction of insulin secretion. Whether this effect is a true consequence of FGFR blockade or involves an off-target effect of the FGFR inhibitor requires additional study. icv FGFR antagonist causes glucose intolerance in rats. This effect is associated with robust sympathoadrenal activation. The sympathoadrenal response is rapid in onset, but clears rapidly. Reduced insulin secretion contributes to FGFR inhibitor-induced glucose intolerance.
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Key Words
- AIRg, acute insulin response to glucose
- AUC, area under the curve
- BIE, basal insulin effect
- CNS, central nervous system
- Central FGF receptors
- DI, disposition index
- FGF receptor inhibitor PD173074
- FGF, fibroblast growth factor
- FGF19, Fibroblast growth factor-19
- FGFR, fibroblast growth factor receptor
- FGFRi, FGFR inhibitor
- FSIGT, frequently sampled intravenous glucose tolerance test
- Frequently sampled intravenous glucose tolerance test
- GE, glucose effectiveness
- GEZI, glucose effectiveness at zero insulin
- Glucose metabolism
- Ibasal, basal insulin
- Kg, glucose disappearance constant
- Minimal model
- NEFA, non-esterified free fatty acids
- SG, glucose effectiveness at basal insulin
- SI, insulin sensitivity
- Sympathoadrenal response
- icv, intracerebroventricular
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Affiliation(s)
- Jennifer M Rojas
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Miles E Matsen
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Thomas O Mundinger
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Gregory J Morton
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Darko Stefanovski
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Karl J Kaiyala
- Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Gerald J Taborsky
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA ; Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
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16
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Meek TH, Matsen ME, Damian V, Cubelo A, Chua SC, Morton GJ. Role of melanocortin signaling in neuroendocrine and metabolic actions of leptin in male rats with uncontrolled diabetes. Endocrinology 2014; 155:4157-67. [PMID: 25137027 PMCID: PMC4197991 DOI: 10.1210/en.2014-1169] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although the antidiabetic effects of leptin require intact neuronal melanocortin signaling in rodents with uncontrolled diabetes (uDM), increased melanocortin signaling is not sufficient to mimic leptin's glucose-lowering effects. The current studies were undertaken to clarify the role of melanocortin signaling in leptin's ability to correct metabolic and neuroendocrine disturbances associated with uDM. To accomplish this, bilateral cannulae were implanted in the lateral ventricle of rats with streptozotocin-induced diabetes, and leptin was coinfused with varying doses of the melanocortin 3/4 receptor (MC3/4R) antagonist, SHU9119. An additional cohort of streptozotocin-induced diabetes rats received intracerebroventricular administration of either the MC3/4R agonist, melanotan-II, or its vehicle. Consistent with previous findings, leptin's glucose-lowering effects were blocked by intracerebroventricular SHU9119. In contrast, leptin-mediated suppression of hyperglucagonemia involves both melanocortin dependent and independent mechanisms, and the degree of glucagon inhibition was associated with reduced plasma ketone body levels. Increased central nervous system melanocortin signaling alone fails to mimic leptin's ability to correct any of the metabolic or neuroendocrine disturbances associated with uDM. Moreover, the inability of increased melanocortin signaling to lower diabetic hyperglycemia does not appear to be secondary to release of the endogenous MC3/4R inverse agonist, Agouti-related peptide (AgRP), because AgRP knockout mice did not show increased susceptibility to the antidiabetic effects of increased MC3/4R signaling. Overall, these data suggest that 1) AgRP is not a major driver of diabetic hyperglycemia, 2) mechanisms independent of melanocortin signaling contribute to leptin's antidiabetic effects, and 3) melanocortin receptor blockade dissociates leptin's glucose-lowering effect from its action on other features of uDM, including reversal of hyperglucagonemia and ketosis, suggesting that brain control of ketosis, but not blood glucose levels, is glucagon dependent.
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Affiliation(s)
- Thomas H Meek
- Diabetes and Obesity Center of Excellence (T.H.M., M.E.M.,. V.D., A.C., G.J.M.), Department of Medicine, University of Washington, Seattle, Washington 98109; and Division of Endocrinology (S.C.C.), Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
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17
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Morton GJ, Matsen ME, Bracy DP, Meek TH, Nguyen HT, Stefanovski D, Bergman RN, Wasserman DH, Schwartz MW. FGF19 action in the brain induces insulin-independent glucose lowering. J Clin Invest 2013; 123:4799-808. [PMID: 24084738 PMCID: PMC3809800 DOI: 10.1172/jci70710] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 08/01/2013] [Indexed: 12/17/2022] Open
Abstract
Insulin-independent glucose disposal (referred to as glucose effectiveness [GE]) is crucial for glucose homeostasis and, until recently, was thought to be invariable. However, GE is reduced in type 2 diabetes and markedly decreased in leptin-deficient ob/ob mice. Strategies aimed at increasing GE should therefore be capable of improving glucose tolerance in these animals. The gut-derived hormone FGF19 has previously been shown to exert potent antidiabetic effects in ob/ob mice. In ob/ob mice, we found that systemic FGF19 administration improved glucose tolerance through its action in the brain and that a single, low-dose i.c.v. injection of FGF19 dramatically improved glucose intolerance within 2 hours. Minimal model analysis of glucose and insulin data obtained during a frequently sampled i.v. glucose tolerance test showed that the antidiabetic effect of i.c.v. FGF19 was solely due to increased GE and not to changes of either insulin secretion or insulin sensitivity. The mechanism underlying this effect appears to involve increased metabolism of glucose to lactate. Together, these findings implicate the brain in the antidiabetic action of systemic FGF19 and establish the brain’s capacity to rapidly, potently, and selectively increase insulin-independent glucose disposal.
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Affiliation(s)
- Gregory J. Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Miles E. Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Deanna P. Bracy
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Thomas H. Meek
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Hong T. Nguyen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Darko Stefanovski
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Richard N. Bergman
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - David H. Wasserman
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Michael W. Schwartz
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.
Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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18
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Meek TH, Matsen ME, Dorfman MD, Guyenet SJ, Damian V, Nguyen HT, Taborsky GJ, Morton GJ. Leptin action in the ventromedial hypothalamic nucleus is sufficient, but not necessary, to normalize diabetic hyperglycemia. Endocrinology 2013; 154:3067-76. [PMID: 23782941 PMCID: PMC3749482 DOI: 10.1210/en.2013-1328] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In rodent models of type 1 diabetes, leptin administration into brain ventricles normalizes blood glucose at doses that have no effect when given peripherally. The ventromedial nucleus of the hypothalamus (VMN) is a potential target for leptin's antidiabetic effects because leptin-sensitive neurons in this brain area are implicated in glucose homeostasis. To test this hypothesis, we injected leptin directly into the bilateral VMN of rats with streptozotocin-induced uncontrolled diabetes mellitus. This intervention completely normalized both hyperglycemia and the elevated rates of hepatic glucose production and plasma glucagon levels but had no effect on tissue glucose uptake in the skeletal muscle or brown adipose tissue as measured using tracer dilution techniques during a basal clamp. To determine whether VMN leptin signaling is required for leptin-mediated normalization of diabetic hyperglycemia, we studied mice in which the leptin receptor gene was deleted in VMN steroidogenic factor 1 neurons using cre-loxP technology. Our findings indicate leptin action within these neurons is not required for the correction of diabetic hyperglycemia by central leptin infusion. We conclude that leptin signaling in the VMN is sufficient to mediate leptin's antidiabetic action but may not be necessary for this effect. Leptin action within a distributed neuronal network may mediate its effects on glucose homeostasis.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/drug therapy
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Glucagon/blood
- Glucagon/metabolism
- Glucagon-Secreting Cells/drug effects
- Glucagon-Secreting Cells/metabolism
- Gluconeogenesis/drug effects
- Hyperglycemia/prevention & control
- Hypoglycemic Agents/administration & dosage
- Hypoglycemic Agents/metabolism
- Hypoglycemic Agents/therapeutic use
- Infusions, Intraventricular
- Injections, Intraventricular
- Leptin/administration & dosage
- Leptin/genetics
- Leptin/metabolism
- Leptin/therapeutic use
- Liver/drug effects
- Liver/metabolism
- Male
- Mice
- Mice, Knockout
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurons/pathology
- Rats
- Rats, Wistar
- Receptors, Leptin/agonists
- Receptors, Leptin/genetics
- Receptors, Leptin/metabolism
- Recombinant Proteins/administration & dosage
- Recombinant Proteins/metabolism
- Recombinant Proteins/therapeutic use
- Signal Transduction/drug effects
- Ventromedial Hypothalamic Nucleus/drug effects
- Ventromedial Hypothalamic Nucleus/metabolism
- Ventromedial Hypothalamic Nucleus/pathology
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Affiliation(s)
- Thomas H Meek
- Diabetes and Obesity Center of Excellence, University of Washington at South Lake Union, 850 Republican Street, N334, Box 358055, Seattle, Washington 98195, USA
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19
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Meek TH, Wisse BE, Thaler JP, Guyenet SJ, Matsen ME, Fischer JD, Taborsky GJ, Schwartz MW, Morton GJ. BDNF action in the brain attenuates diabetic hyperglycemia via insulin-independent inhibition of hepatic glucose production. Diabetes 2013; 62:1512-8. [PMID: 23274899 PMCID: PMC3636618 DOI: 10.2337/db12-0837] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent evidence suggests that central leptin administration fully normalizes hyperglycemia in a rodent model of uncontrolled insulin-deficient diabetes by reducing hepatic glucose production (HGP) and by increasing glucose uptake. The current studies were undertaken to determine whether brain-derived neurotrophic factor (BDNF) action in the brain lowers blood glucose in uncontrolled insulin-deficient diabetes and to investigate the mechanisms mediating this effect. Adult male rats implanted with cannulas to either the lateral cerebral ventricle or the ventromedial hypothalamic nucleus (VMN) received either vehicle or streptozotocin to induce uncontrolled insulin-deficient diabetes. Three days later, animals received daily intracerebroventricular or intra-VMN injections of either BDNF or its vehicle. We found that repeated daily intracerebroventricular administration of BDNF attenuated diabetic hyperglycemia independent of changes in food intake. Instead, using tracer dilution techniques during a basal clamp, we found that BDNF lowered blood glucose levels by potently suppressing HGP, without affecting tissue glucose uptake, an effect associated with normalization of both plasma glucagon levels and hepatic expression of gluconeogenic genes. Moreover, BDNF microinjection directly into the VMN also lowered fasting blood glucose levels in uncontrolled insulin-deficient diabetes, but this effect was modest compared with intracerebroventricular administration. We conclude that central nervous system BDNF attenuates diabetic hyperglycemia via an insulin-independent mechanism. This action of BDNF likely involves the VMN and is associated with inhibition of glucagon secretion and a decrease in the rate of HGP.
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Affiliation(s)
- Thomas H. Meek
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Brent E. Wisse
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Joshua P. Thaler
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Stephan J. Guyenet
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Miles E. Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Jonathan D. Fischer
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Gerald J. Taborsky
- Veterans Affairs Puget Sound Health Care System, Veterans Affairs Medical Center, Seattle, Washington
| | - Michael W. Schwartz
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Gregory J. Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
- Corresponding author: Gregory J. Morton,
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20
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Matsen ME, Thaler JP, Wisse BE, Guyenet SJ, Meek TH, Ogimoto K, Cubelo A, Fischer JD, Kaiyala KJ, Schwartz MW, Morton GJ. In uncontrolled diabetes, thyroid hormone and sympathetic activators induce thermogenesis without increasing glucose uptake in brown adipose tissue. Am J Physiol Endocrinol Metab 2013; 304:E734-46. [PMID: 23384771 PMCID: PMC3625754 DOI: 10.1152/ajpendo.00488.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent advances in human brown adipose tissue (BAT) imaging technology have renewed interest in the identification of BAT activators for the treatment of obesity and diabetes. In uncontrolled diabetes (uDM), activation of BAT is implicated in glucose lowering mediated by intracerebroventricular (icv) administration of leptin, which normalizes blood glucose levels in streptozotocin (STZ)-induced diabetic rats. The potent effect of icv leptin to increase BAT glucose uptake in STZ-diabetes is accompanied by the return of reduced plasma thyroxine (T4) levels and BAT uncoupling protein-1 (Ucp1) mRNA levels to nondiabetic controls. We therefore sought to determine whether activation of thyroid hormone receptors is sufficient in and of itself to lower blood glucose levels in STZ-diabetes and whether this effect involves activation of BAT. We found that, although systemic administration of the thyroid hormone (TR)β-selective agonist GC-1 increases energy expenditure and induces further weight loss in STZ-diabetic rats, it neither increased BAT glucose uptake nor attenuated diabetic hyperglycemia. Even when GC-1 was administered in combination with a β(3)-adrenergic receptor agonist to mimic sympathetic nervous system activation, glucose uptake was not increased in STZ-diabetic rats, nor was blood glucose lowered, yet this intervention potently activated BAT. Similar results were observed in animals treated with active thyroid hormone (T3) instead of GC-1. Taken together, our data suggest that neither returning normal plasma thyroid hormone levels nor BAT activation has any impact on diabetic hyperglycemia, and that in BAT, increases of Ucp1 gene expression and glucose uptake are readily dissociated from one another in this setting.
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Affiliation(s)
- Miles E Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, WA, USA
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21
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Guyenet SJ, Matsen ME, Morton GJ, Kaiyala KJ, Schwartz MW. Rapid glutamate release in the mediobasal hypothalamus accompanies feeding and is exaggerated by an obesogenic food. Mol Metab 2013; 2:116-22. [PMID: 24199157 DOI: 10.1016/j.molmet.2013.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 02/02/2013] [Accepted: 02/04/2013] [Indexed: 10/27/2022] Open
Abstract
The mediobasal hypothalamus (MBH) plays a central role in the regulation of food intake and energy balance. Although the excitatory neurotransmitter glutamate is implicated in energy balance regulation by the MBH, the hypothesis that feeding elicits local glutamate release remains untested. To test this hypothesis, we employed a glutamate biosensor that measures glutamate concentrations at 1-s intervals in conscious, freely behaving rats. Results indicate that feeding is associated with an increase of MBH glutamate concentration that occurs within 1-2 s of oral contact with a food pellet, and the glutamate response to a palatable high-fat pellet is greatly exaggerated relative to chow. In contrast, glutamate responses were not observed during water ingestion or other observed behaviors. These findings indicate that feeding is associated with rapid release of glutamate in the MBH, that this release is exaggerated with an obesogenic food, and that this response is likely stimulated by orosensory factors.
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Affiliation(s)
- Stephan J Guyenet
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, UW Medicine at South Lake Union, 850 Republican Street, Box 358055, Seattle, WA 98109, USA
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22
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Thaler JP, Yi CX, Schur EA, Guyenet SJ, Hwang BH, Dietrich MO, Zhao X, Sarruf DA, Izgur V, Maravilla KR, Nguyen HT, Fischer JD, Matsen ME, Wisse BE, Morton GJ, Horvath TL, Baskin DG, Tschöp MH, Schwartz MW. Obesity is associated with hypothalamic injury in rodents and humans. J Clin Invest 2012. [DOI: 10.1172/jci62813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Thaler JP, Yi CX, Schur EA, Guyenet SJ, Hwang BH, Dietrich MO, Zhao X, Sarruf DA, Izgur V, Maravilla KR, Nguyen HT, Fischer JD, Matsen ME, Wisse BE, Morton GJ, Horvath TL, Baskin DG, Tschöp MH, Schwartz MW. Obesity is associated with hypothalamic injury in rodents and humans. J Clin Invest 2011; 122:153-62. [PMID: 22201683 DOI: 10.1172/jci59660] [Citation(s) in RCA: 1269] [Impact Index Per Article: 97.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/02/2011] [Indexed: 01/21/2023] Open
Abstract
Rodent models of obesity induced by consuming high-fat diet (HFD) are characterized by inflammation both in peripheral tissues and in hypothalamic areas critical for energy homeostasis. Here we report that unlike inflammation in peripheral tissues, which develops as a consequence of obesity, hypothalamic inflammatory signaling was evident in both rats and mice within 1 to 3 days of HFD onset, prior to substantial weight gain. Furthermore, both reactive gliosis and markers suggestive of neuron injury were evident in the hypothalamic arcuate nucleus of rats and mice within the first week of HFD feeding. Although these responses temporarily subsided, suggesting that neuroprotective mechanisms may initially limit the damage, with continued HFD feeding, inflammation and gliosis returned permanently to the mediobasal hypothalamus. Consistent with these data in rodents, we found evidence of increased gliosis in the mediobasal hypothalamus of obese humans, as assessed by MRI. These findings collectively suggest that, in both humans and rodent models, obesity is associated with neuronal injury in a brain area crucial for body weight control.
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Affiliation(s)
- Joshua P Thaler
- Division of Metabolism, Endocrinology and Nutrition, Diabetes and Obesity Center of Excellence, University of Washington, Seattle, Washington 98109, USA
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German JP, Thaler JP, Wisse BE, Oh-I S, Sarruf DA, Matsen ME, Fischer JD, Taborsky GJ, Schwartz MW, Morton GJ. Leptin activates a novel CNS mechanism for insulin-independent normalization of severe diabetic hyperglycemia. Endocrinology 2011; 152:394-404. [PMID: 21159853 PMCID: PMC3037161 DOI: 10.1210/en.2010-0890] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The brain has emerged as a target for the insulin-sensitizing effects of several hormonal and nutrient-related signals. The current studies were undertaken to investigate mechanisms whereby leptin lowers circulating blood glucose levels independently of insulin. After extending previous evidence that leptin infusion directly into the lateral cerebral ventricle ameliorates hyperglycemia in rats with streptozotocin-induced uncontrolled diabetes mellitus, we showed that the underlying mechanism is independent of changes of food intake, urinary glucose excretion, or recovery of pancreatic β-cells. Instead, leptin action in the brain potently suppresses hepatic glucose production while increasing tissue glucose uptake despite persistent, severe insulin deficiency. This leptin action is distinct from its previously reported effect to increase insulin sensitivity in the liver and offers compelling evidence that the brain has the capacity to normalize diabetic hyperglycemia in the presence of sufficient amounts of central nervous system leptin.
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Affiliation(s)
- Jonathan P German
- Department of Medicine, University of Washington at South Lake Union, 815 Mercer Street, N334, PO Box 358055, Seattle, Washington 98195, USA
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German JP, Wisse BE, Thaler JP, Oh-I S, Sarruf DA, Ogimoto K, Kaiyala KJ, Fischer JD, Matsen ME, Taborsky GJ, Schwartz MW, Morton GJ. Leptin deficiency causes insulin resistance induced by uncontrolled diabetes. Diabetes 2010; 59:1626-34. [PMID: 20424233 PMCID: PMC2889761 DOI: 10.2337/db09-1918] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Depletion of body fat stores during uncontrolled, insulin-deficient diabetes (uDM) results in markedly reduced plasma leptin levels. This study investigated the role of leptin deficiency in the genesis of severe insulin resistance and related metabolic and neuroendocrine derangements induced by uDM. RESEARCH DESIGN AND METHODS Adult male Wistar rats remained nondiabetic or were injected with the beta-cell toxin, streptozotocin (STZ) to induce uDM and subsequently underwent subcutaneous implantation of an osmotic minipump containing either vehicle or leptin at a dose (150 microg/kg/day) designed to replace leptin at nondiabetic plasma levels. To control for leptin effects on food intake, another group of STZ-injected animals were pair fed to the intake of those receiving leptin. Food intake, body weight, and blood glucose levels were measured daily, with body composition and indirect calorimetry performed on day 11, and an insulin tolerance test to measure insulin sensitivity performed on day 16. Plasma hormone and substrate levels, hepatic gluconeogenic gene expression, and measures of tissue insulin signal transduction were also measured. RESULTS Physiologic leptin replacement prevented insulin resistance in uDM via a mechanism unrelated to changes in food intake or body weight. This effect was associated with reduced total body fat and hepatic triglyceride content, preservation of lean mass, and improved insulin signal transduction via the insulin receptor substrate-phosphatidylinositol-3-hydroxy kinase pathway in the liver, but not in skeletal muscle or adipose tissue. Although physiologic leptin replacement lowered blood glucose levels only slightly, it fully normalized elevated plasma glucagon and corticosterone levels and reversed the increased hepatic expression of gluconeogenic enzymes characteristic of rats with uDM. CONCLUSIONS We conclude that leptin deficiency plays a key role in the pathogenesis of severe insulin resistance and related endocrine disorders in uDM. Treatment of diabetes in humans may benefit from correction of leptin deficiency as well as insulin deficiency.
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Affiliation(s)
- Jonathan P. German
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Brent E. Wisse
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Joshua P. Thaler
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Shinsuke Oh-I
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - David A. Sarruf
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Kayoko Ogimoto
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Karl J. Kaiyala
- Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle, Washington
| | - Jonathan D. Fischer
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Miles E. Matsen
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Gerald J. Taborsky
- VA Puget Sound Health Care System, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Michael W. Schwartz
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
| | - Gregory J. Morton
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington, Seattle, Washington
- Corresponding author: Gregory J. Morton,
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