1
|
Tu L, He Y, Xu Y. Anoctamin 4 defines glucose-inhibited neurons in the ventromedial hypothalamus. Neural Regen Res 2024; 19:1177-1178. [PMID: 37905852 DOI: 10.4103/1673-5374.385867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/02/2023] [Indexed: 11/02/2023] Open
Affiliation(s)
- Longlong Tu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA (Tu L, Xu Y)
| | - Yanlin He
- Brain Glycemic and Metabolism Control Department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA (He Y)
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA (Tu L, Xu Y)
- Department of Molecular and Cellular Biology; Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX, USA (Xu Y)
| |
Collapse
|
2
|
Arshad MF, Walkinshaw E, Solomon AL, Bernjak A, Rombach I, Leelarathna L, Little SA, Evans M, Shaw JAM, Heller SR, Iqbal A. Diabetic autonomic neuropathy does not impede improvement in hypoglycaemia awareness in adults: Sub-study results from the HypoCOMPaSS trial. Diabet Med 2024:e15340. [PMID: 38741266 DOI: 10.1111/dme.15340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/22/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
AIMS Impaired awareness of hypoglycaemia (IAH) increases the risk of severe hypoglycaemia in people with type 1 diabetes mellitus (T1DM). IAH can be reversed through meticulous avoidance of hypoglycaemia. Diabetic autonomic neuropathy (DAN) has been proposed as an underlying mechanism contributing to IAH; however, data are inconsistent. The aim of this study was to examine the effects of cardiac autonomic neuropathy (CAN) on IAH reversibility inT1DM. METHODS Participants with T1DM and IAH (Gold score ≥4) recruited to the HypoCOMPaSS (24-week 2 × 2 factorial randomised controlled) trial were included. All underwent screening for cardiac autonomic function testing at baseline and received comparable education and support aimed at avoiding hypoglycaemia and improving hypoglycaemia awareness. Definite CAN was defined as the presence of ≥2 abnormal cardiac reflex tests. Participants were grouped according to their CAN status, and changes in Gold score were compared. RESULTS Eighty-three participants (52 women [62.7%]) were included with mean age (SD) of 48 (12) years and mean HbA1c of 66 (13) mmol/mol (8.2 [3.3] %). The mean duration of T1DM was 29 (13) years. The prevalence of CAN was low with 5/83 (6%) participants having definite autonomic neuropathy with 11 (13%) classified with possible/early neuropathy. All participants, regardless of the autonomic function status, showed a mean improvement in Gold score of ≥1 (mean improvement -1.2 [95% CI -0.8, -1.6]; p < 0.001). CONCLUSIONS IAH can be improved in people with T1DM, and a long duration of disease, with and without cardiac autonomic dysfunction. These data suggest that CAN is not a prime driver for modulating IAH reversibility.
Collapse
Affiliation(s)
- Muhammad Fahad Arshad
- University of Sheffield, Sheffield, UK
- Sheffield Teaching Hospitals, NHS Foundation Trust, Sheffield, UK
| | - Emma Walkinshaw
- University of Sheffield, Sheffield, UK
- Sheffield Teaching Hospitals, NHS Foundation Trust, Sheffield, UK
| | | | | | | | - Lala Leelarathna
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
| | - Stuart A Little
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
- Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - Mark Evans
- MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - James A M Shaw
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
- Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - Simon R Heller
- University of Sheffield, Sheffield, UK
- Sheffield Teaching Hospitals, NHS Foundation Trust, Sheffield, UK
| | - Ahmed Iqbal
- University of Sheffield, Sheffield, UK
- Sheffield Teaching Hospitals, NHS Foundation Trust, Sheffield, UK
| |
Collapse
|
3
|
Macon EL, Devore MH, Lin YK, Music MB, Wooten M, McMullen CA, Woodcox AM, Marksbury AR, Beckner Z, Patel BV, Schoeder LA, Iles AN, Fisher SJ. Current and future therapies to treat impaired awareness of hypoglycemia. Front Pharmacol 2023; 14:1271814. [PMID: 37942482 PMCID: PMC10628050 DOI: 10.3389/fphar.2023.1271814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023] Open
Abstract
In order to achieve optimal glycemic control, intensive insulin regimes are needed for individuals with Type 1 Diabetes (T1D) and insulin-dependent Type 2 Diabetes (T2D). Unfortunately, intensive glycemic control often results in insulin-induced hypoglycemia. Moreover, recurrent episodes of hypoglycemia result in both the loss of the characteristic warning symptoms associated with hypoglycemia and an attenuated counterregulatory hormone responses. The blunting of warning symptoms is known as impaired awareness of hypoglycemia (IAH). Together, IAH and the loss of the hormonal response is termed hypoglycemia associated autonomic failure (HAAF). IAH is prevalent in up to 25% in people with T1D and up to 10% in people with T2D. IAH and HAAF increase the risk of severe hypoglycemia 6-fold and 25-fold, respectively. To reduce this risk for severe hypoglycemia, multiple different therapeutic approaches are being explored that could improve awareness of hypoglycemia. Current therapies to improve awareness of hypoglycemia include patient education and psychoeducation, the use of novel glycemic control technology, pancreas/islet transplantation, and drug therapy. This review examines both existing therapies and potential therapies that are in pre-clinical testing. Novel treatments that improve awareness of hypoglycemia, via improving the counterregulatory hormone responses or improving hypoglycemic symptom recognition, would also shed light on the possible neurological mechanisms that lead to the development of IAH. To reduce the risk of severe hypoglycemia in people with diabetes, elucidating the mechanism behind IAH, as well as developing targeted therapies is currently an unmet need for those that suffer from IAH.
Collapse
Affiliation(s)
- Erica L. Macon
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Micah H. Devore
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Yu Kuei Lin
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Megan B. Music
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Mason Wooten
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Colleen A. McMullen
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Andrea M. Woodcox
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Ashlee R. Marksbury
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Zachary Beckner
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Bansi V. Patel
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Lily A. Schoeder
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Ashley N. Iles
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Simon J. Fisher
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| |
Collapse
|
4
|
Mahmood ASMH, Roy SC, Leprince J, Briski KP. Sex-dependent endozepinergic regulation of ventromedial hypothalamic nucleus glucose counter-regulatory neuron aromatase protein expression in the adult rat. J Chem Neuroanat 2023; 132:102323. [PMID: 37543285 PMCID: PMC10528386 DOI: 10.1016/j.jchemneu.2023.102323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023]
Abstract
The hypothalamic brain cell types that produce estradiol from testosterone remain unclear. Aromatase inhibition affects ventromedial hypothalamic nucleus (VMN) glucose-stimulatory nitric oxide (NO) and glucose-inhibitory γ-aminobutyric acid (GABA) transmission during insulin (INS)-induced hypoglycemia (IIH). Pure GABA and NO nerve cell samples acquired by laser-catapult-microdissection from consecutive rostro-caudal segments of the VMN were analyzed by Western blot to investigate whether regional subpopulations of each cell type contain machinery for neuro-estradiol synthesis. Astrocyte endozepinergic signaling governs brain steroidogenesis. Pharmacological tools were used here to determine if the glio-peptide octadecaneuropeptide (ODN) controls aromatase expression in GABA and NO neurons during eu- and/or hypoglycemia. Intracerebroventricular administration of the ODN G-protein coupled-receptor antagonist cyclo(1-8)[DLeu5]OP (LV-1075) decreased (male) or enhanced (female) VMN GABAergic neuron aromatase expression, but increased or reduced this profile in nitrergic neurons in a region-specific manner in each sex. IIH suppressed aromatase levels in GABA neurons located in the middle segment of the male VMN or distributed throughout this nucleus in the female. This inhibitory response was altered by the ODN isoactive surrogate octapeptide (OP) in female, but was refractory to OP in male. NO neuron aromatase protein in hypoglycemic male (middle and caudal VMN) and female (rostral and caudal VMN) rats, but was normalized in OP- plus INS-treated rats of both sexes. Results provide novel evidence that VMN glucose-regulatory neurons may produce neuro-estradiol, and that the astrocyte endozepine transmitter ODN may impose sex-specific control of baseline and/or hypoglycemic patterns of aromatase expression in distinct subsets of nitrergic and GABAergic neurons in this neural structure.
Collapse
Affiliation(s)
- A S M Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA
| | - Sagor C Roy
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA
| | - Jérôme Leprince
- Univ Rouen Normandie, Inserm, NorDic UMR 1239, PRIMACEN, Rouen, France
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA.
| |
Collapse
|
5
|
Bheemanapally K, Briski KP. Differential G Protein-Coupled Estrogen Receptor-1 Regulation of Counter-Regulatory Transmitter Marker and 5'-AMP-Activated Protein Kinase Expression in Ventrolateral versus Dorsomedial Ventromedial Hypothalamic Nucleus. Neuroendocrinology 2023; 114:25-41. [PMID: 37699381 PMCID: PMC10843453 DOI: 10.1159/000533627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023]
Abstract
INTRODUCTION The ventromedial hypothalamic nucleus (VMN) is an estrogen receptor (ER)-rich structure that regulates glucostasis. The role of nuclear but not membrane G protein-coupled ER-1 (GPER) in that function has been studied. METHODS Gene silencing and laser-catapult microdissection/immunoblot tools were used to examine whether GPER regulates transmitter and energy sensor function in dorsomedial (VMNdm) and/or ventrolateral (VMNvl) VMN counter-regulatory nitrergic and γ-Aminobutyric acid (GABA) neurons. RESULTS Intra-VMN GPER siRNA administration to euglycemic animals did not affect VMNdm or -vl nitrergic neuron nitric oxide synthase (nNOS), but upregulated (VMNdm) or lacked influence on (VMNvl) GABA nerve cell glutamate decarboxylase65/67 (GAD) protein. Insulin-induced hypoglycemia (IIH) caused GPER knockdown-reversible augmentation of nNOS, 5'-AMP-activated protein kinase (AMPK), and phospho-AMPK proteins in nitrergic neurons in both divisions. IIH had dissimilar effects on VMNvl (unchanged) versus VMNdm (increased) GABAergic neuron GAD levels, yet GPER knockdown affected these profiles. GPER siRNA prevented hypoglycemic upregulation of VMNvl and -dm GABA neuron AMPK without altering pAMPK expression. CONCLUSIONS Outcomes infer that GPER exerts differential control of VMNdm versus -vl GABA transmission during glucostasis and is required for hypoglycemic upregulated nitrergic (VMNdm and -vl) and GABA (VMNdm) signaling. Glycogen metabolism is reported to regulate VMN nNOS and GAD proteins. Data show that GPER limits VMNvl glycogen phosphorylase (GP) protein expression and glycogen buildup during euglycemia but mediates hypoglycemic augmentation of VMNvl GP protein and glycogen content; VMNdm glycogen mass is refractory to GPER control. GPER regulation of VMNvl glycogen metabolism infers that this receptor may govern local counter-regulatory transmission in part by astrocyte metabolic coupling.
Collapse
Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, USA
| |
Collapse
|
6
|
Tu L, Bean JC, He Y, Liu H, Yu M, Liu H, Zhang N, Yin N, Han J, Scarcelli NA, Conde KM, Wang M, Li Y, Feng B, Gao P, Cai ZL, Fukuda M, Xue M, Tong Q, Yang Y, Liao L, Xu J, Wang C, He Y, Xu Y. Anoctamin 4 channel currents activate glucose-inhibited neurons in the mouse ventromedial hypothalamus during hypoglycemia. J Clin Invest 2023; 133:e163391. [PMID: 37261917 PMCID: PMC10348766 DOI: 10.1172/jci163391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 05/30/2023] [Indexed: 06/03/2023] Open
Abstract
Glucose is the basic fuel essential for maintenance of viability and functionality of all cells. However, some neurons - namely, glucose-inhibited (GI) neurons - paradoxically increase their firing activity in low-glucose conditions and decrease that activity in high-glucose conditions. The ionic mechanisms mediating electric responses of GI neurons to glucose fluctuations remain unclear. Here, we showed that currents mediated by the anoctamin 4 (Ano4) channel are only detected in GI neurons in the ventromedial hypothalamic nucleus (VMH) and are functionally required for their activation in response to low glucose. Genetic disruption of the Ano4 gene in VMH neurons reduced blood glucose and impaired counterregulatory responses during hypoglycemia in mice. Activation of VMHAno4 neurons increased food intake and blood glucose, while chronic inhibition of VMHAno4 neurons ameliorated hyperglycemia in a type 1 diabetic mouse model. Finally, we showed that VMHAno4 neurons represent a unique orexigenic VMH population and transmit a positive valence, while stimulation of neurons that do not express Ano4 in the VMH (VMHnon-Ano4) suppress feeding and transmit a negative valence. Together, our results indicate that the Ano4 channel and VMHAno4 neurons are potential therapeutic targets for human diseases with abnormal feeding behavior or glucose imbalance.
Collapse
Affiliation(s)
- Longlong Tu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Jonathan C. Bean
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yang He
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Hailan Liu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Meng Yu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Hesong Liu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Nan Zhang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Na Yin
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Junying Han
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Nikolas A. Scarcelli
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Kristine M. Conde
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Mengjie Wang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yongxiang Li
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Bing Feng
- Brain glycemic and metabolism control department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Peiyu Gao
- Brain glycemic and metabolism control department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Zhao-Lin Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Makoto Fukuda
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Yongjie Yang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Lan Liao
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Chunmei Wang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yanlin He
- Brain glycemic and metabolism control department, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Yong Xu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
7
|
Roy SC, Sapkota S, Pasula MB, Bheemanapally K, Briski KP. Diazepam Binding Inhibitor Control of Eu- and Hypoglycemic Patterns of Ventromedial Hypothalamic Nucleus Glucose-Regulatory Signaling. ASN Neuro 2023; 15:17590914231214116. [PMID: 38031405 PMCID: PMC10687944 DOI: 10.1177/17590914231214116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 10/20/2023] [Accepted: 10/28/2023] [Indexed: 12/01/2023] Open
Abstract
Pharmacological stimulation/antagonism of astrocyte glio-peptide octadecaneuropeptide signaling alters ventromedial hypothalamic nucleus (VMN) counterregulatory γ-aminobutyric acid (GABA) and nitric oxide transmission. The current research used newly developed capillary zone electrophoresis-mass spectrometry methods to investigate hypoglycemia effects on VMN octadecaneuropeptide content, along with gene knockdown tools to determine if octadecaneuropeptide signaling regulates these transmitters during eu- and/or hypoglycemia. Hypoglycemia caused dissimilar adjustments in the octadecaneuropeptide precursor, i.e., diazepam-binding-inhibitor and octadecaneuropeptide levels in dorsomedial versus ventrolateral VMN. Intra-VMN diazepam-binding-inhibitor siRNA administration decreased baseline 67 and 65 kDa glutamate decarboxylase mRNA levels in GABAergic neurons laser-microdissected from each location, but only affected hypoglycemic transcript expression in ventrolateral VMN. This knockdown therapy imposed dissimilar effects on eu- and hypoglycemic glucokinase and 5'-AMP-activated protein kinase-alpha1 (AMPKα1) and -alpha2 (AMPKα2) gene profiles in dorsomedial versus ventrolateral GABAergic neurons. Diazepam-binding-inhibitor gene silencing up-regulated baseline (dorsomedial) or hypoglycemic (ventrolateral) nitrergic neuron neuronal nitric oxide synthase mRNA profiles. Baseline nitrergic cell glucokinase mRNA was up- (ventrolateral) or down- (dorsomedial) regulated by diazepam-binding-inhibitor siRNA, but knockdown enhanced hypoglycemic profiles in both sites. Nitrergic nerve cell AMPKα1 and -α2 transcripts exhibited division-specific responses to this genetic manipulation during eu- and hypoglycemia. Results document the utility of capillary zone electrophoresis-mass spectrometric tools for quantification of ODN in small-volume brain tissue samples. Data show that hypoglycemia has dissimilar effects on ODN signaling in the two major neuroanatomical divisions of the VMN and that this glio-peptide imposes differential control of glucose-regulatory neurotransmission in the VMNdm versus VMNvl during eu- and hypoglycemia.
Collapse
Affiliation(s)
- Sagor C. Roy
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, USA
| | - Subash Sapkota
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, USA
| | - Madhu Babu Pasula
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, USA
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, USA
| | - Karen P. Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA, USA
| |
Collapse
|
8
|
Alhamyani A, Napit PR, Bheemanapally K, Sylvester PW, Briski KP. Singular versus combinatory glucose-sensitive signal control of metabolic sensor protein profiles in hypothalamic astrocyte cultures from each sex. Transl Neurosci 2022; 13:408-420. [DOI: 10.1515/tnsci-2022-0259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/08/2022] [Accepted: 10/21/2022] [Indexed: 12/05/2022] Open
Abstract
Abstract
Brain metabolic-sensory targets for modulatory glucose-sensitive endocrine and neurochemical signals remain unidentified. A hypothalamic astrocyte primary culture model was here used to investigate whether glucocorticoid receptor (GR) and noradrenergic signals regulate astrocyte glucose (glucose transporter-2 [GLUT2], glucokinase) and/or energy (5′-AMP-activated protein kinase [AMPK]) sensor reactivity to glucoprivation by sex. Glucose-supplied astrocytes of each sex showed increased GLUT2 expression after incubation with the GR agonist dexamethasone (DEX) or norepinephrine (NE); DEX plus NE (DEX/NE) augmented GLUT2 in the female, but not in male. Glucoprivation did not alter GLUT2 expression, but eliminated NE regulation of this protein in both sexes. Male and female astrocyte glucokinase profiles were refractory to all drug treatments, but were down-regulated by glucoprivation. Glucoprivation altered AMPK expression in male only, and caused divergent sex-specific changes in activated, i.e., phosphoAMPK (pAMPK) levels. DEX or DEX/NE inhibited (male) or stimulated (female) AMPK and pAMPK proteins in both glucose-supplied and -deprived astrocytes. In male, NE coincidently up-regulated AMPK and inhibited pAMPK profiles in glucose-supplied astrocytes; these effects were abolished by glucoprivation. In female, AMPK profiles were unaffected by NE irrespective of glucose status, whereas pAMPK expression was up-regulated by NE only during glucoprivation. Present outcomes document, for each sex, effects of glucose status on hypothalamic astrocyte glucokinase, AMPK, and pAMPK protein expression and on noradrenergic control of these profiles. Data also show that DEX and NE regulation of GLUT2 is sex-monomorphic, but both stimuli impose divergent sex-specific effects on AMPK and pAMPK. Further effort is warranted to characterize mechanisms responsible for sex-dimorphic GR and noradrenergic governance of hypothalamic astrocyte energy sensory function.
Collapse
Affiliation(s)
- Abdulrahman Alhamyani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe , Rm 356 Bienville Building, 1800 Bienville Drive , Monroe, LA 71201 , United States ; Pharmaceuticals Chemistry Department, Faculty of Clinical Pharmacy, Al Baha University , Al Baha city, 65779, Saudi Arabia
| | - Prabhat R. Napit
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe , Rm 356 Bienville Building, 1800 Bienville Drive , Monroe, LA 71201 , United States ; Pharmaceuticals Chemistry Department, Faculty of Clinical Pharmacy, Al Baha University , Al Baha city, 65779, Saudi Arabia
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe , Rm 356 Bienville Building, 1800 Bienville Drive , Monroe, LA 71201 , United States ; Pharmaceuticals Chemistry Department, Faculty of Clinical Pharmacy, Al Baha University , Al Baha city, 65779, Saudi Arabia
| | - Paul W. Sylvester
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe , Rm 356 Bienville Building, 1800 Bienville Drive , Monroe, LA 71201 , United States ; Pharmaceuticals Chemistry Department, Faculty of Clinical Pharmacy, Al Baha University , Al Baha city, 65779, Saudi Arabia
| | - Karen P. Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe , Rm 356 Bienville Building, 1800 Bienville Drive , Monroe, LA 71201 , United States ; Pharmaceuticals Chemistry Department, Faculty of Clinical Pharmacy, Al Baha University , Al Baha city, 65779, Saudi Arabia
| |
Collapse
|
9
|
Wang Q, Zhang B, Stutz B, Liu ZW, Horvath TL, Yang X. Ventromedial hypothalamic OGT drives adipose tissue lipolysis and curbs obesity. SCIENCE ADVANCES 2022; 8:eabn8092. [PMID: 36044565 PMCID: PMC9432828 DOI: 10.1126/sciadv.abn8092] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 07/14/2022] [Indexed: 05/31/2023]
Abstract
The ventromedial hypothalamus (VMH) is known to regulate body weight and counterregulatory response. However, how VMH neurons regulate lipid metabolism and energy balance remains unknown. O-linked β-d-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation), catalyzed by O-GlcNAc transferase (OGT), is considered a cellular sensor of nutrients and hormones. Here, we report that genetic ablation of OGT in VMH neurons inhibits neuronal excitability. Mice with VMH neuron-specific OGT deletion show rapid weight gain, increased adiposity, and reduced energy expenditure, without significant changes in food intake or physical activity. The obesity phenotype is associated with adipocyte hypertrophy and reduced lipolysis of white adipose tissues. In addition, OGT deletion in VMH neurons down-regulates the sympathetic activity and impairs the sympathetic innervation of white adipose tissues. These findings identify OGT in the VMH as a homeostatic set point that controls body weight and underscore the importance of the VMH in regulating lipid metabolism through white adipose tissue-specific innervation.
Collapse
Affiliation(s)
- Qi Wang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA
| | - Bichen Zhang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA
| | - Bernardo Stutz
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Zhong-Wu Liu
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tamas L. Horvath
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
- Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xiaoyong Yang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
- Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| |
Collapse
|
10
|
Tu L, Fukuda M, Tong Q, Xu Y. The ventromedial hypothalamic nucleus: watchdog of whole-body glucose homeostasis. Cell Biosci 2022; 12:71. [PMID: 35619170 PMCID: PMC9134642 DOI: 10.1186/s13578-022-00799-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/25/2022] [Indexed: 02/06/2023] Open
Abstract
The brain, particularly the ventromedial hypothalamic nucleus (VMH), has been long known for its involvement in glucose sensing and whole-body glucose homeostasis. However, it is still not fully understood how the brain detects and responds to the changes in the circulating glucose levels, as well as brain-body coordinated control of glucose homeostasis. In this review, we address the growing evidence implicating the brain in glucose homeostasis, especially in the contexts of hypoglycemia and diabetes. In addition to neurons, we emphasize the potential roles played by non-neuronal cells, as well as extracellular matrix in the hypothalamus in whole-body glucose homeostasis. Further, we review the ionic mechanisms by which glucose-sensing neurons sense fluctuations of ambient glucose levels. We also introduce the significant implications of heterogeneous neurons in the VMH upon glucose sensing and whole-body glucose homeostasis, in which sex difference is also addressed. Meanwhile, research gaps have also been identified, which necessities further mechanistic studies in future.
Collapse
Affiliation(s)
- Longlong Tu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA
| | - Makoto Fukuda
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yong Xu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street #8066, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
11
|
Estrogenic Action in Stress-Induced Neuroendocrine Regulation of Energy Homeostasis. Cells 2022; 11:cells11050879. [PMID: 35269500 PMCID: PMC8909319 DOI: 10.3390/cells11050879] [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: 12/21/2021] [Revised: 02/16/2022] [Accepted: 02/28/2022] [Indexed: 01/27/2023] Open
Abstract
Estrogens are among important contributing factors to many sex differences in neuroendocrine regulation of energy homeostasis induced by stress. Research in this field is warranted since chronic stress-related psychiatric and metabolic disturbances continue to be top health concerns, and sex differences are witnessed in these aspects. For example, chronic stress disrupts energy homeostasis, leading to negative consequences in the regulation of emotion and metabolism. Females are known to be more vulnerable to the psychological consequences of stress, such as depression and anxiety, whereas males are more vulnerable to the metabolic consequences of stress. Sex differences that exist in the susceptibility to various stress-induced disorders have led researchers to hypothesize that gonadal hormones are regulatory factors that should be considered in stress studies. Further, estrogens are heavily recognized for their protective effects on metabolic dysregulation, such as anti-obesogenic and glucose-sensing effects. Perturbations to energy homeostasis using laboratory rodents, such as physiological stress or over-/under- feeding dietary regimen prevalent in today’s society, offer hints to the underlying mechanisms of estrogenic actions. Metabolic effects of estrogens primarily work through estrogen receptor α (ERα), which is differentially expressed between the sexes in hypothalamic nuclei regulating energy metabolism and in extrahypothalamic limbic regions that are not typically associated with energy homeostasis. In this review, we discuss estrogenic actions implicated in stress-induced sex-distinct metabolic disorders.
Collapse
|
12
|
The Case for Clinical Trials with Novel GABAergic Drugs in Diabetes Mellitus and Obesity. Life (Basel) 2022; 12:life12020322. [PMID: 35207609 PMCID: PMC8876029 DOI: 10.3390/life12020322] [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: 01/22/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
Obesity and diabetes mellitus have become the surprising menaces of relative economic well-being worldwide. Gamma amino butyric acid (GABA) has a prominent role in the control of blood glucose, energy homeostasis as well as food intake at several levels of regulation. The effects of GABA in the body are exerted through ionotropic GABAA and metabotropic GABAB receptors. This treatise will focus on the pharmacologic targeting of GABAA receptors to reap beneficial therapeutic effects in diabetes mellitus and obesity. A new crop of drugs selectively targeting GABAA receptors has been under investigation for efficacy in stroke recovery and cognitive deficits associated with schizophrenia. Although these trials have produced mixed outcomes the compounds are safe to use in humans. Preclinical evidence is summarized here to support the rationale of testing some of these compounds in diabetic patients receiving insulin in order to achieve better control of blood glucose levels and to combat the decline of cognitive performance. Potential therapeutic benefits could be achieved (i) By resetting the hypoglycemic counter-regulatory response; (ii) Through trophic actions on pancreatic islets, (iii) By the mobilization of antioxidant defence mechanisms in the brain. Furthermore, preclinical proof-of-concept work, as well as clinical trials that apply the novel GABAA compounds in eating disorders, e.g., olanzapine-induced weight-gain, also appear warranted.
Collapse
|
13
|
Zheng Y, Chen Z. Targeting Histamine and Histamine Receptors for the Precise Regulation of Feeding. Curr Top Behav Neurosci 2021; 59:355-387. [PMID: 34622397 DOI: 10.1007/7854_2021_258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Histamine has long been accepted as an anorexigenic agent. However, lines of evidence have suggested that the roles of histamine in feeding behaviors are much more complex than previously thought, being involved in satiety, satiation, feeding motivation, feeding circadian rhythm, and taste perception and memory. The functional diversity of histamine makes it a viable target for clinical management of obesity and other feeding-related disorders. Here, we update the current knowledge about the functions of histamine in feeding and summarize the underlying molecular and neural circuit mechanisms. Finally, we review the main clinical studies about the impacts of histamine-related compounds on weight control and discuss insights into future research on the roles of histamine in feeding. Despite the recent progress in histamine research, the histaminergic feeding circuits are poorly understood, and it is also worth verifying the functions of histamine receptors in a more spatiotemporally specific manner.
Collapse
Affiliation(s)
- Yanrong Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
| |
Collapse
|
14
|
Meneyrol K, Estévez-Salguero Á, González-García I, Guitton J, Taouis M, Benomar Y, Magnan C, López M, Le Stunff H. Ovarian insufficiency impairs glucose-stimulated insulin secretion through activation of hypothalamic de novo ceramide synthesis. Metabolism 2021; 123:154846. [PMID: 34371064 DOI: 10.1016/j.metabol.2021.154846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/25/2021] [Accepted: 08/02/2021] [Indexed: 12/20/2022]
Abstract
Oestrogens regulate body weight through their action on hypothalamus to modulate food intake and energy expenditure. Hypothalamic de novo ceramide synthesis plays a central role on obesity induced by oestrogen deficiency. Depletion in oestrogens is also known to be associated with glucose intolerance, which favours type 2 diabetes (T2D). However, the implication of hypothalamic ceramide in the regulation of glucose homeostasis by oestrogen is unknown. Here, we studied glucose homeostasis and insulin secretion in ovariectomized (OVX) female rats. OVX induces body weight gain associated with a hypothalamic inflammation and impaired glucose homeostasis. Genetic blockade of ceramide synthesis in the ventromedial nucleus of the hypothalamus (VMH) reverses hypothalamic inflammation and partly restored glucose tolerance induced by OVX. Furthermore, glucose-stimulated insulin secretion (GSIS) is increased in OVX rats due to a raise of insulin secretion second phase, a characteristic of early stage of T2D. In contrast, GSIS from isolated islets of OVX rats is totally blunted. Inhibition of ceramide synthesis in the VMH restores GSIS from isolated OVX islets and represses the second phase of insulin secretion. Stimulation of oestrogen receptor α (ERα) by oestradiol (E2) down-regulates ceramide synthesis in hypothalamic neuronal GT1-7 cells but no in microglial SIM-A9 cells. In contrast, genetic inactivation of ERα in VMH upregulates ceramide synthesis. These results indicate that hypothalamic neuronal de novo ceramide synthesis triggers the OVX-dependent impairment of glucose homeostasis which is partly mediated by a dysregulation of GSIS.
Collapse
Affiliation(s)
- Kelly Meneyrol
- Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Université de Paris, Paris, France
| | - Ánxela Estévez-Salguero
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Ismael González-García
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Jeanne Guitton
- Institut des Neurosciences Paris-Saclay, CNRS UMR 9197, Université Paris Saclay, Orsay, France
| | - Mohammed Taouis
- Institut des Neurosciences Paris-Saclay, CNRS UMR 9197, Université Paris Saclay, Orsay, France
| | - Yacir Benomar
- Institut des Neurosciences Paris-Saclay, CNRS UMR 9197, Université Paris Saclay, Orsay, France
| | - Christophe Magnan
- Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Université de Paris, Paris, France
| | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain.
| | - Hervé Le Stunff
- Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Université de Paris, Paris, France; Institut des Neurosciences Paris-Saclay, CNRS UMR 9197, Université Paris Saclay, Orsay, France.
| |
Collapse
|
15
|
Bheemanapally K, Napit PR, Ibrahim MMH, Briski KP. UHPLC-electrospray ionization-mass spectrometric analysis of brain cell-specific glucogenic and neurotransmitter amino acid content. Sci Rep 2021; 11:16079. [PMID: 34373537 PMCID: PMC8352916 DOI: 10.1038/s41598-021-95646-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Astrocyte glycogen, the primary energy reserve in brain, undergoes continuous remodeling by glucose passage through the glycogen shunt prior to conversion to the oxidizable energy fuel L-lactate. Glucogenic amino acids (GAAs) are a potential non-glucose energy source during neuro-metabolic instability. Current research investigated whether diminished glycogen metabolism affects GAA homeostasis in astrocyte and/or nerve cell compartments. The glycogen phosphorylase (GP) inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) was injected into the ventromedial hypothalamic nucleus (VMN), a key metabolic-sensing structure, before vehicle or L-lactate infusion. Pure VMN astrocyte and metabolic-sensory neuron samples were obtained by combinatory immunocytochemistry/laser-catapult-microdissection for UHPLC-electrospray ionization-mass spectrometry (LC-ESI-MS) GAA analysis. DAB inhibition of VMN astrocyte aspartate and glutamine (Gln) levels was prevented or exacerbated, respectively, by lactate. VMN gluco-stimulatory nitric oxide (NO; neuronal nitric oxide synthase-immunoreactive (ir)-positive) and gluco-inhibitory γ-aminobutyric acid (GABA; glutamate decarboxylase65/67-ir-positive) neurons exhibited lactate-reversible asparate and glutamate augmentation by DAB, but dissimilar Gln responses to DAB. GP inhibition elevated NO and GABA nerve cell GABA content, but diminished astrocyte GABA; these responses were averted by lactate in neuron, but not astrocyte samples. Outcomes provide proof-of-principle of requisite LC-ESI-MS sensitivity for GAA measurement in specific brain cell populations. Results document divergent effects of decreased VMN glycogen breakdown on astrocyte versus neuron GAAs excepting Gln. Lactate-reversible DAB up-regulation of metabolic-sensory neuron GABA signaling may reflect compensatory nerve cell energy stabilization upon decline in astrocyte-derived metabolic fuel.
Collapse
Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Prabhat R Napit
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA.
| |
Collapse
|
16
|
Picard A, Metref S, Tarussio D, Dolci W, Berney X, Croizier S, Labouebe G, Thorens B. Fgf15 Neurons of the Dorsomedial Hypothalamus Control Glucagon Secretion and Hepatic Gluconeogenesis. Diabetes 2021; 70:1443-1457. [PMID: 33883213 PMCID: PMC8336003 DOI: 10.2337/db20-1121] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 04/03/2021] [Indexed: 11/18/2022]
Abstract
The counterregulatory response to hypoglycemia is an essential survival function. It is controlled by an integrated network of glucose-responsive neurons, which trigger endogenous glucose production to restore normoglycemia. The complexity of this glucoregulatory network is, however, only partly characterized. In a genetic screen of a panel of recombinant inbred mice we previously identified Fgf15, expressed in neurons of the dorsomedial hypothalamus (DMH), as a negative regulator of glucagon secretion. Here, we report on the generation of Fgf15CretdTomato mice and their use to further characterize these neurons. We show that they were glutamatergic and comprised glucose-inhibited and glucose-excited neurons. When activated by chemogenetics, Fgf15 neurons prevented the increase in vagal nerve firing and the secretion of glucagon normally triggered by insulin-induced hypoglycemia. On the other hand, they increased the activity of the sympathetic nerve in the basal state and prevented its silencing by glucose overload. Higher sympathetic tone increased hepatic Creb1 phosphorylation, Pck1 mRNA expression, and hepatic glucose production leading to glucose intolerance. Thus, Fgf15 neurons of the DMH participate in the counterregulatory response to hypoglycemia by a direct adrenergic stimulation of hepatic glucose production while suppressing vagally induced glucagon secretion. This study provides new insights into the complex neuronal network that prevents the development of hypoglycemia.
Collapse
Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Salima Metref
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Wanda Dolci
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Gwenaël Labouebe
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
17
|
Castorena CM, Caron A, Michael NJ, Ahmed NI, Arnold AG, Lee J, Lee C, Limboy C, Tinajero AS, Granier M, Wang S, Horton JD, Holland WL, Lee S, Liu C, Fujikawa T, Elmquist JK. CB1Rs in VMH neurons regulate glucose homeostasis but not body weight. Am J Physiol Endocrinol Metab 2021; 321:E146-E155. [PMID: 34097543 PMCID: PMC8321828 DOI: 10.1152/ajpendo.00044.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cannabinoid 1 receptor (CB1R) inverse agonists reduce body weight and improve several parameters of glucose homeostasis. However, these drugs have also been associated with deleterious side effects. CB1R expression is widespread in the brain and in peripheral tissues, but whether specific sites of expression can mediate the beneficial metabolic effects of CB1R drugs, while avoiding the untoward side effects, remains unclear. Evidence suggests inverse agonists may act on key sites within the central nervous system to improve metabolism. The ventromedial hypothalamus (VMH) is a critical node regulating energy balance and glucose homeostasis. To determine the contributions of CB1Rs expressed in VMH neurons in regulating metabolic homeostasis, we generated mice lacking CB1Rs in the VMH. We found that the deletion of CB1Rs in the VMH did not affect body weight in chow- and high-fat diet-fed male and female mice. We also found that deletion of CB1Rs in the VMH did not alter weight loss responses induced by the CB1R inverse agonist SR141716. However, we did find that CB1Rs of the VMH regulate parameters of glucose homeostasis independent of body weight in diet-induced obese male mice.NEW & NOTEWORTHY Cannabinoid 1 receptors (CB1Rs) regulate metabolic homeostasis, and CB1R inverse agonists reduce body weight and improve parameters of glucose metabolism. However, the cell populations expressing CB1Rs that regulate metabolic homeostasis remain unclear. CB1Rs are highly expressed in the ventromedial hypothalamic nucleus (VMH), which is a crucial node that regulates metabolism. With CRISPR/Cas9, we generated mice lacking CB1Rs specifically in VMH neurons and found that CB1Rs in VMH neurons are essential for the regulation of glucose metabolism independent of body weight regulation.
Collapse
Affiliation(s)
- Carlos M Castorena
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Alexandre Caron
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Natalie J Michael
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Newaz I Ahmed
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Amanda G Arnold
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jiwon Lee
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Charlotte Lee
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Chelsea Limboy
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Arely Salazar Tinajero
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Madison Granier
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Simeng Wang
- Department of Molecular Genetics, University of Utah, Salt Lake City, Utah
| | - Jay D Horton
- Department of Molecular Genetics, University of Utah, Salt Lake City, Utah
| | - William L Holland
- Department of Biochemistry, Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Syann Lee
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Chen Liu
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Teppei Fujikawa
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas
| |
Collapse
|
18
|
Kaneko K, Lin HY, Fu Y, Saha PK, De la Puente-Gomez AB, Xu Y, Ohinata K, Chen P, Morozov A, Fukuda M. Rap1 in the VMH regulates glucose homeostasis. JCI Insight 2021; 6:142545. [PMID: 33974562 PMCID: PMC8262364 DOI: 10.1172/jci.insight.142545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet–induced (HFD-induced) obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in steroidogenic factor-1–positive (SF-1–positive) neurons in the ventromedial hypothalamic nucleus (VMH) known to regulate glucose metabolism. While having no effect on body weight regardless of sex, diet, and age, Rap1 deficiency in the VMH SF1 neurons markedly lowered blood glucose and insulin levels, improved glucose and insulin tolerance, and protected mice against HFD-induced neural leptin resistance and peripheral insulin resistance at the cellular and whole-body levels. Last, acute pharmacological inhibition of brain exchange protein directly activated by cAMP 2, a direct activator of Rap1, corrected glucose imbalance in obese mouse models. Our findings uncover the primary role of VMH Rap1 in glycemic control and implicate Rap1 signaling as a potential target for therapeutic intervention in diabetes.
Collapse
Affiliation(s)
- Kentaro Kaneko
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Hsiao-Yun Lin
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yukiko Fu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Ana B De la Puente-Gomez
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Peter Chen
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, NIH, Maryland, USA.,Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, USA
| | - Makoto Fukuda
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
19
|
Bheemanapally K, Ibrahim MMH, Alshamrani A, Briski KP. Ventromedial hypothalamic nucleus glycogen regulation of metabolic-sensory neuron AMPK and neurotransmitter expression: role of lactate. Am J Physiol Regul Integr Comp Physiol 2021; 320:R791-R799. [PMID: 33825506 PMCID: PMC8285616 DOI: 10.1152/ajpregu.00292.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/18/2021] [Accepted: 03/31/2021] [Indexed: 12/23/2022]
Abstract
Astrocyte glycogen is dynamically remodeled during metabolic stability and provides oxidizable l-lactate equivalents during neuroglucopenia. Current research investigated the hypothesis that ventromedial hypothalamic nucleus (VMN) glycogen metabolism controls glucostimulatory nitric oxide (NO) and/or glucoinhibitory gamma-aminobutyric acid (GABA) neuron 5'-AMP-activated protein kinase (AMPK) and transmitter marker, e.g., neuronal nitric oxide synthase (nNOS), and glutamate decarboxylase65/67 (GAD) protein expression. Adult ovariectomized estradiol-implanted female rats were injected into the VMN with the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) before vehicle or l-lactate infusion. Western blot analysis of laser-catapult-microdissected nitrergic and GABAergic neurons showed that DAB caused lactate-reversible upregulation of nNOS and GAD proteins. DAB suppressed or increased total AMPK content of NO and GABA neurons, respectively, by lactate-independent mechanisms, but lactate prevented drug enhancement of pAMPK expression in nitrergic neurons. Inhibition of VMN glycogen disassembly caused divergent changes in counter-regulatory hormone, e.g. corticosterone (increased) and glucagon (decreased) secretion. Outcomes show that VMN glycogen metabolism controls local glucoregulatory transmission by means of lactate signal volume. Results implicate glycogen-derived lactate deficiency as a physiological stimulus of corticosterone release. Concurrent normalization of nitrergic neuron nNOS and pAMPK protein and corticosterone secretory response to DAB by lactate infers that the hypothalamic-pituitary-adrenal axis may be activated by VMN NO-mediated signals of cellular energy imbalance.
Collapse
Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana
| | - Ayed Alshamrani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana
| |
Collapse
|
20
|
Melanocortin 3 receptor-expressing neurons in the ventromedial hypothalamus promote glucose disposal. Proc Natl Acad Sci U S A 2021; 118:2103090118. [PMID: 33827930 PMCID: PMC8053962 DOI: 10.1073/pnas.2103090118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The ventromedial hypothalamus (VMH) is a critical neural node that senses blood glucose and promotes glucose utilization or mobilization during hypoglycemia. The VMH neurons that control these distinct physiologic processes are largely unknown. Here, we show that melanocortin 3 receptor (Mc3R)-expressing VMH neurons (VMHMC3R) sense glucose changes both directly and indirectly via altered excitatory input. We identify presynaptic nodes that potentially regulate VMHMC3R neuronal activity, including inputs from proopiomelanocortin (POMC)-producing neurons in the arcuate nucleus. We find that VMHMC3R neuron activation blunts, and their silencing enhances glucose excursion following a glucose load. Overall, these findings demonstrate that VMHMC3R neurons are a glucose-responsive hypothalamic subpopulation that promotes glucose disposal upon activation; this highlights a potential site for targeting dysregulated glycemia.
Collapse
|
21
|
Sejling AS, Wang P, Zhu W, Farhat R, Knight N, Appadurai D, Chan O. Repeated Activation of Noradrenergic Receptors in the Ventromedial Hypothalamus Suppresses the Response to Hypoglycemia. Endocrinology 2021; 162:6052997. [PMID: 33367607 PMCID: PMC7814298 DOI: 10.1210/endocr/bqaa241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/19/2022]
Abstract
Activation of the adrenergic system in response to hypoglycemia is important for proper recovery from low glucose levels. However, it has been suggested that repeated adrenergic stimulation may also contribute to counterregulatory failure, but the underlying mechanisms are not known. The aim of this study was to establish whether repeated activation of noradrenergic receptors in the ventromedial hypothalamus (VMH) contributes to blunting of the counterregulatory response by enhancing local lactate production. The VMH of nondiabetic rats were infused with either artificial extracellular fluid, norepinephrine (NE), or salbutamol for 3 hours/day for 3 consecutive days before they underwent a hypoglycemic clamp with microdialysis to monitor changes in VMH lactate levels. Repeated exposure to NE or salbutamol suppressed both the glucagon and epinephrine responses to hypoglycemia compared to controls. Furthermore, antecedent NE and salbutamol treatments raised extracellular lactate levels in the VMH. To determine whether the elevated lactate levels were responsible for impairing the hormone response, we pharmacologically inhibited neuronal lactate transport in a subgroup of NE-treated rats during the clamp. Blocking neuronal lactate utilization improved the counterregulatory hormone responses in NE-treated animals, suggesting that repeated activation of VMH β2-adrenergic receptors increases local lactate levels which in turn, suppresses the counterregulatory hormone response to hypoglycemia.
Collapse
Affiliation(s)
- Anne-Sophie Sejling
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Dyrehavevej, Denmark
- Current Affiliation: A.S. is currently with Novo Nordisk A/S
| | - Peili Wang
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Wanling Zhu
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Rawad Farhat
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Nicholas Knight
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Daniel Appadurai
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Owen Chan
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
- Correspondence: Dr. Owen Chan, PhD, University of Utah, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, 15 North 2030 East, Rm 2420B, Salt Lake City, UT 84112, USA.
| |
Collapse
|
22
|
In-Depth Analysis of the Plasma Proteome in ME/CFS Exposes Disrupted Ephrin-Eph and Immune System Signaling. Proteomes 2021; 9:proteomes9010006. [PMID: 33572894 PMCID: PMC7931008 DOI: 10.3390/proteomes9010006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 02/06/2023] Open
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling disease with worldwide prevalence and limited therapies exclusively aimed at treating symptoms. To gain insights into the molecular disruptions in ME/CFS, we utilized an aptamer-based technology that quantified 4790 unique human proteins, allowing us to obtain the largest proteomics dataset yet available for this disease, detecting highly abundant proteins as well as rare proteins over a nine-log dynamic range. We report a pilot study of 20 ME/CFS patients and 20 controls, all females. Significant differences in the levels of 19 proteins between cohorts implicate pathways related to the extracellular matrix, the immune system and cell-cell communication. Outputs of pathway and cluster analyses robustly highlight the ephrin pathway, which is involved in cell-cell signaling and regulation of an expansive variety of biological processes, including axon guidance, angiogenesis, epithelial cell migration, and immune response. Receiver Operating Characteristic (ROC) curve analyses distinguish the plasma proteomes of ME/CFS patients from controls with a high degree of accuracy (Area Under the Curve (AUC) > 0.85), and even higher when using protein ratios (AUC up to 0.95), that include some protein pairs with established biological relevance. Our results illustrate the promise of plasma proteomics for diagnosing and deciphering the molecular basis of ME/CFS.
Collapse
|
23
|
Alhamyani A, Mahmood AH, Alshamrani A, Ibrahim MMH, Briski KP. Central Type II Glucocorticoid Receptor Regulation of Ventromedial Hypothalamic Nucleus Glycogen Metabolic Enzyme and Glucoregulatory Neurotransmitter Marker Protein Expression in the Male Rat. JOURNAL OF ENDOCRINOLOGY AND DIABETES 2021; 8:148. [PMID: 34258390 PMCID: PMC8274514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The ventromedial hypothalamic nucleus (VMN) glucoregulatory neurotransmitters γ-aminobutyric acid (GABA) and nitric oxide (NO) signal adjustments in glycogen mobilization. Glucocorticoids control astrocyte glycogen metabolism in vitro. The classical (type II) glucocorticoid receptor (GR) is expressed in key brain structures that govern glucostasis, including the VMN. Current research addressed the hypothesis that forebrain GR regulation of VMN glycogen synthase (GS) and phosphorylase (GP) protein expression correlates with control of glucoregulatory transmission. Groups of male rats were pretreated by intracerebroventricular (icv) delivery of the GR antagonist RU486 or vehicle prior to insulin-induced hypoglycemia (IIH), or were pretreated icv with dexamethasone (DEX) or vehicle before subcutaneous insulin diluent injection. DEX increased VMN GS and norepinephrine-sensitive GP-muscle type (GPmm), but did not alter metabolic deficit-sensitive GP-brain type (GPbb) expression. RU486 enhanced GS and GPbb profiles during IIH. VMN astrocyte (MCT1) and neuronal (MCT2) monocarboxylate transporter profiles were up-regulated in euglycemic and hypoglycemic animals by DEX or RU486, respectively. Glutamate decarboxylase65/67 and neuronal nitric oxide synthase (nNOS) proteins were both increased by DEX, yet RU486 augmented hypoglycemic nNOS expression patterns. Results show that GR exert divergent effects on VMN GS, MCT1/2, and nNOS proteins during eu- (stimulatory) versus hypoglycemia (inhibitory); these findings imply that up-regulated NO transmission may reflect, in part, augmented glucose incorporation into glycogen and/or increased tissue lactate requirements. Data also provide novel evidence for metabolic state-dependent GR regulation of VMN GPmm and GPbb profiles; thus, GABA signaling of metabolic stability may reflect, in part, stimulus-specific glycogen breakdown during eu- versus hypoglycemia.
Collapse
Affiliation(s)
- Abdulrahman Alhamyani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201
| | - A.S.M. Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201
| | - Ayed Alshamrani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201
| | - Mostafa M. H. Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201
| | - Karen P. Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201
| |
Collapse
|
24
|
Uddin MM, Ibrahim MMH, Briski KP. Sex-dimorphic neuroestradiol regulation of ventromedial hypothalamic nucleus glucoregulatory transmitter and glycogen metabolism enzyme protein expression in the rat. BMC Neurosci 2020; 21:51. [PMID: 33238883 PMCID: PMC7687823 DOI: 10.1186/s12868-020-00598-w] [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: 06/18/2020] [Accepted: 10/30/2020] [Indexed: 12/19/2022] Open
Abstract
Background Ventromedial hypothalamic nucleus (VMN) gluco-regulatory transmission is subject to sex-specific control by estradiol. The VMN is characterized by high levels of aromatase expression. Methods The aromatase inhibitor letrozole (LZ) was used with high-resolution microdissection/Western blot techniques to address the hypothesis that neuroestradiol exerts sex-dimorphic control of VMN neuronal nitric oxide synthase (nNOS) and glutamate decarboxylase65/67 (GAD) protein expression. Glycogen metabolism impacts VMN nNOS and GAD profiles; here, LZ treatment effects on VMN glycogen synthase (GS) and phosphorylase brain- (GPbb; glucoprivic-sensitive) and muscle (GPmm; norepinephrine-sensitive) variant proteins were examined. Results VMN aromatase protein content was similar between sexes. Intracerebroventricular LZ infusion of testes-intact male and ovariectomized, estradiol-replaced female rats blocked insulin-induced hypoglycemic (IIH) up-regulation of this profile. LZ exerted sex-contingent effects on basal VMN nNOS and GAD expression, but blocked IIH-induced NO stimulation and GAD suppression in each sex. Sex-contingent LZ effects on basal and hypoglycemic patterns of GPbb and GPmm expression occurred at distinctive levels of the VMN. LZ correspondingly down- or up-regulated baseline pyruvate recycling pathway marker protein expression in males (glutaminase) and females (malic enzyme-1), and altered INS effects on those proteins. Conclusions Results infer that neuroestradiol is required in each sex for optimal VMN metabolic transmitter signaling of hypoglycemic energy deficiency. Sex differences in VMN GP variant protein levels and sensitivity to aromatase may correlate with sex-dimorphic glycogen mobilization during this metabolic stress. Neuroestradiol may also exert sex-specific effects on glucogenic amino acid energy yield by actions on distinctive enzyme targets in each sex.
Collapse
Affiliation(s)
- Md Main Uddin
- Willis-Knighton Endowed Professor of Pharmacy and Director, School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Mostafa M H Ibrahim
- Willis-Knighton Endowed Professor of Pharmacy and Director, School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA
| | - Karen P Briski
- Willis-Knighton Endowed Professor of Pharmacy and Director, School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, 356 Bienville Building, 1800 Bienville Drive, Monroe, LA, 71201, USA.
| |
Collapse
|
25
|
Lin YK, Fisher SJ, Pop‐Busui R. Hypoglycemia unawareness and autonomic dysfunction in diabetes: Lessons learned and roles of diabetes technologies. J Diabetes Investig 2020; 11:1388-1402. [PMID: 32403204 PMCID: PMC7610104 DOI: 10.1111/jdi.13290] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/01/2020] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
Impaired awareness of hypoglycemia (IAH) is a reduction in the ability to recognize low blood glucose levels that would otherwise prompt an appropriate corrective therapy. Identified in approximately 25% of patients with type 1 diabetes, IAH has complex pathophysiology, and might lead to serious and potentially lethal consequences in patients with diabetes, particularly in those with more advanced disease and comorbidities. Continuous glucose monitoring systems can provide real-time glucose information and generate timely alerts on rapidly falling or low blood glucose levels. Given their improvements in accuracy, affordability and integration with insulin pump technology, continuous glucose monitoring systems are emerging as critical tools to help prevent serious hypoglycemia and mitigate its consequences in patients with diabetes. This review discusses the current knowledge on IAH and effective diagnostic methods, the relationship between hypoglycemia and cardiovascular autonomic neuropathy, a practical approach to evaluating cardiovascular autonomic neuropathy for clinicians, and recent evidence from clinical trials assessing the effects of the use of CGM technologies in patients with type 1 diabetes with IAH.
Collapse
Affiliation(s)
- Yu Kuei Lin
- Division of Metabolism, Endocrinology and DiabetesDepartment of Internal MedicineUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Simon J Fisher
- Division of Endocrinology, Metabolism and DiabetesDepartment of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
| | - Rodica Pop‐Busui
- Division of Metabolism, Endocrinology and DiabetesDepartment of Internal MedicineUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| |
Collapse
|
26
|
Alshamrani AA, Bheemanapally K, Ibrahim MMH, Briski KP. Impact of caudal hindbrain glycogen metabolism on A2 noradrenergic neuron AMPK activation and ventromedial hypothalamic nucleus norepinephrine activity and glucoregulatory neurotransmitter marker protein expression. Neuropeptides 2020; 82:102055. [PMID: 32451071 PMCID: PMC7354902 DOI: 10.1016/j.npep.2020.102055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 01/06/2023]
Abstract
The brain glycogen reserve is a source of oxidizable substrate fuel. Lactoprivic-sensitive hindbrain A2 noradrenergic neurons provide crucial metabolic-sensory input to downstream hypothalamic glucose-regulatory structures. Current research examined whether hindbrain glycogen fuel supply impacts A2 energy stability and governance of ventromedial hypothalamic nucleus (VMN) metabolic transmitter signaling. Male rats were injected into the caudal fourth ventricle (CV4) with the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) prior to continuous intra-CV4 infusion of L-lactate or vehicle. Lactate reversed DAB suppression of A2 neuron AMPK protein and up-regulated phosphoAMPK profiles. A2 dopamine-β-hydroxylase expression was refractory to DAB, but elevated by DAB/lactate. Lactate normalized A2 estrogen receptor-alpha and GPER proteins and up-regulated estrogen receptor-beta levels in DAB-treated rats. VMN norepinephrine content was decreased by DAB, but partially restored by lactate. DAB caused lactate-reversible or -irreversible augmentation of VMN glycogen phosphorylase-brain (GPbb) and -muscle type (GPmm) variant profiles, and correspondingly up- or down-regulated VMN protein markers of glucose-stimulatory nitrergic and glucose-inhibitory γ-aminobutyric acid transmission. DAB did not alter plasma glucose, but suppressed or elevated circulating glucagon and corticosterone in that order. Results show that diminished hindbrain glycogen breakdown is communicated to the VMN, in part by NE signaling, to up-regulate VMN glycogen breakdown and trigger neurochemical signaling of energy imbalance in that site. DAB effects on GPmm, VMN glycogen content, and counter-regulatory hormone secretion were unabated by lactate infusion, suggesting that aside from substrate fuel provision rate, additional indicators of glycogen metabolism such as turnover rate may be monitored in the hindbrain.
Collapse
Affiliation(s)
- Ayed A Alshamrani
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States.
| |
Collapse
|
27
|
Interaction of glucose sensing and leptin action in the brain. Mol Metab 2020; 39:101011. [PMID: 32416314 PMCID: PMC7267726 DOI: 10.1016/j.molmet.2020.101011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/27/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023] Open
Abstract
Background In response to energy abundant or deprived conditions, nutrients and hormones activate hypothalamic pathways to maintain energy and glucose homeostasis. The underlying CNS mechanisms, however, remain elusive in rodents and humans. Scope of review Here, we first discuss brain glucose sensing mechanisms in the presence of a rise or fall of plasma glucose levels, and highlight defects in hypothalamic glucose sensing disrupt in vivo glucose homeostasis in high-fat fed, obese, and/or diabetic conditions. Second, we discuss brain leptin signalling pathways that impact glucose homeostasis in glucose-deprived and excessed conditions, and propose that leptin enhances hypothalamic glucose sensing and restores glucose homeostasis in short-term high-fat fed and/or uncontrolled diabetic conditions. Major conclusions In conclusion, we believe basic studies that investigate the interaction of glucose sensing and leptin action in the brain will address the translational impact of hypothalamic glucose sensing in diabetes and obesity.
Collapse
|
28
|
He Y, Xu P, Wang C, Xia Y, Yu M, Yang Y, Yu K, Cai X, Qu N, Saito K, Wang J, Hyseni I, Robertson M, Piyarathna B, Gao M, Khan SA, Liu F, Chen R, Coarfa C, Zhao Z, Tong Q, Sun Z, Xu Y. Estrogen receptor-α expressing neurons in the ventrolateral VMH regulate glucose balance. Nat Commun 2020; 11:2165. [PMID: 32358493 PMCID: PMC7195451 DOI: 10.1038/s41467-020-15982-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
Brain glucose-sensing neurons detect glucose fluctuations and prevent severe hypoglycemia, but mechanisms mediating functions of these glucose-sensing neurons are unclear. Here we report that estrogen receptor-α (ERα)-expressing neurons in the ventrolateral subdivision of the ventromedial hypothalamic nucleus (vlVMH) can sense glucose fluctuations, being glucose-inhibited neurons (GI-ERαvlVMH) or glucose-excited neurons (GE-ERαvlVMH). Hypoglycemia activates GI-ERαvlVMH neurons via the anoctamin 4 channel, and inhibits GE-ERαvlVMH neurons through opening the ATP-sensitive potassium channel. Further, we show that GI-ERαvlVMH neurons preferentially project to the medioposterior arcuate nucleus of the hypothalamus (mpARH) and GE-ERαvlVMH neurons preferentially project to the dorsal Raphe nuclei (DRN). Activation of ERαvlVMH to mpARH circuit and inhibition of ERαvlVMH to DRN circuit both increase blood glucose. Thus, our results indicate that ERαvlVMH neurons detect glucose fluctuations and prevent severe hypoglycemia in mice.
Collapse
Affiliation(s)
- Yanlin He
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Pingwen Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Chunmei Wang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yan Xia
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Meng Yu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yongjie Yang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kaifan Yu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xing Cai
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Na Qu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kenji Saito
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Julia Wang
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ilirjana Hyseni
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Matthew Robertson
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Badrajee Piyarathna
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Min Gao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Sohaib A Khan
- Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Feng Liu
- Departments of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, 78229, USA
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Zheng Sun
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
29
|
Schwartsburd P. A View on Pathogenesis of ≪Vicious Cancer Progression Cycle≫. Front Oncol 2020; 10:690. [PMID: 32426290 PMCID: PMC7204907 DOI: 10.3389/fonc.2020.00690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/14/2020] [Indexed: 12/19/2022] Open
Abstract
Unrestricted tumor growth requires a permanent supply of glucose that can be obtained from cancer-stimulated hepatic glucose production and/or glucose redirecting from host insulin resistant tissues to cancer cells. This study proposes a mechanism based on metabolic and hormonal changes that may provoke glucose delivery to cancer cells through two interconnected "vicious cycles" whose continuous activity drives cancer progression. As follows from the proposed here feedback model, these "vicious cycles" result from cancer-mediated manipulation of host glucose sensors. The derived conclusions contribute to a better understanding of cancer pathogenesis and identifying potential therapeutic targets.
Collapse
Affiliation(s)
- Polina Schwartsburd
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia
| |
Collapse
|
30
|
Carbohydrate Intake in the Context of Exercise in People with Type 1 Diabetes. Nutrients 2019; 11:nu11123017. [PMID: 31835538 PMCID: PMC6950062 DOI: 10.3390/nu11123017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 02/06/2023] Open
Abstract
Although the benefits of regular exercise on cardiovascular risk factors are well established for people with type 1 diabetes (T1D), glycemic control remains a challenge during exercise. Carbohydrate consumption to fuel the exercise bout and/or for hypoglycemia prevention is an important cornerstone to maintain performance and avoid hypoglycemia. The main strategies pertinent to carbohydrate supplementation in the context of exercise cover three aspects: the amount of carbohydrates ingested (i.e., quantity in relation to demands to fuel exercise and avoid hypoglycemia), the timing of the intake (before, during and after the exercise, as well as circadian factors), and the quality of the carbohydrates (encompassing differing carbohydrate types, as well as the context within a meal and the associated macronutrients). The aim of this review is to comprehensively summarize the literature on carbohydrate intake in the context of exercise in people with T1D.
Collapse
|
31
|
Scott SN, Shepherd SO, Strauss JA, Wagenmakers AJM, Cocks M. Home-based high-intensity interval training reduces barriers to exercise in people with type 1 diabetes. Exp Physiol 2019; 105:571-578. [PMID: 31584734 DOI: 10.1113/ep088097] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/03/2019] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the topic of this review? This symposium review provides an overview of the recent work investigating whether a virtually monitored home-based high-intensity interval training (Home-HIT) intervention reduces the fear of hypoglycaemia and other common barriers to exercise in people with type 1 diabetes. What advances does it highlight? Home-HIT seems to offer a strategy to reduce fear of hypoglycaemia, while simultaneously removing other known barriers that prevent people with type 1 diabetes from taking up exercise, because it is time efficient, requires no travel time or costs associated with gym memberships, and allows people to exercise in their chosen environment. ABSTRACT People with type 1 diabetes (T1D) are recommended to engage in regular exercise for a variety of health and fitness reasons. However, many lead a sedentary lifestyle and fail to meet the physical activity guidelines, in part because of the challenge of managing blood glucose concentration and fear of hypoglycaemia. A number of strategies designed to help people with T1D to manage their blood glucose during and after exercise have been investigated. Although many of these strategies show promise in facilitating blood glucose management during and after exercise, they do not target the many other common barriers to exercise that people with T1D face, such as difficulty with cost and travel time to gyms, limited access to exercise bikes and treadmills, and a possible dislike of exercising in front of others in public places. In this symposium review, we provide an overview of ongoing research into a virtually monitored home-based high-intensity interval training (Home-HIT) programme that is designed to reduce these other common barriers to exercise. The conclusion of this review is that Home-HIT seems to offer a strategy to reduce fear of hypoglycaemia, while simultaneously removing other known barriers preventing people with T1D from taking up exercise, such as being time efficient, requiring no travel time or costs associated with gym memberships, and giving them the opportunity to exercise in their chosen environment, reducing the embarrassment experienced by some when exercising in public.
Collapse
Affiliation(s)
- Sam N Scott
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Bern University Hospital, University of Bern, Bern, Switzerland.,Team Novo Nordisk Professional Cycling Team, Atlanta, GA, USA
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Juliette A Strauss
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Matt Cocks
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| |
Collapse
|
32
|
Agrawal R, Durupt G, Verma D, Montgomery M, Vieira-de Abreu A, Taylor C, Swaminathan S, Fisher SJ. MicroRNA-7a overexpression in VMH restores the sympathoadrenal response to hypoglycemia. JCI Insight 2019; 4:130521. [PMID: 31619588 PMCID: PMC6824313 DOI: 10.1172/jci.insight.130521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/31/2019] [Indexed: 12/19/2022] Open
Abstract
It is proposed that the impaired sympathoadrenal response to hypoglycemia induced by recurrent insulin-induced hypoglycemia (RH) is an adaptive phenomenon induced by specific changes in microRNA expression in the ventromedial hypothalamus (VMH). To test this hypothesis, genome-wide microRNAomic profiling of the VMH by RNA-sequencing was performed in control rats and rats treated for RH. Differential expression analysis identified microRNA-7a-5p and microRNA-665 as potential mediators of this phenomenon. To further test this hypothesis, experiments were conducted consisting of targeted lentiviral-mediated overexpression of microRNA-7a-5p and downregulation of microRNA-665 in the VMH. Hyperinsulinemic hypoglycemic clamp experiments demonstrated that targeted overexpression of microRNA-7a-5p (but not downregulation of microRNA-665) in the VMH of RH rats restored the epinephrine response to hypoglycemia. This restored response to hypoglycemia was associated with a restoration of GABAA receptor gene expression. Finally, a direct interaction of microRNA-7a-5p with the 3'-UTR of GABAA receptor α1-subunit (Gabra1) gene was demonstrated in a luciferase assay. These findings indicate that (a) the impaired sympathoadrenal response RH induces is associated with changes in VMH microRNA expression and (b) microRNA-7a-5p, possibly via direct downregulation of GABA receptor gene expression, may serve as a mediator of the altered sympathoadrenal response to hypoglycemia.
Collapse
Affiliation(s)
- Rahul Agrawal
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | - Griffin Durupt
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | - Dinesh Verma
- Division of Infectious Diseases, Department of Internal Medicine, and
| | - Michael Montgomery
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | | | - Casey Taylor
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | | | - Simon J. Fisher
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
- Department of Biochemistry, School of Medicine, University of Utah, Salt Lake City, USA
| |
Collapse
|
33
|
Uddin MM, Mahmood ASMH, Ibrahim MMH, Briski KP. Sex-dimorphic estrogen receptor regulation of ventromedial hypothalamic nucleus glucoregulatory neuron adrenergic receptor expression in hypoglycemic male and female rats. Brain Res 2019; 1720:146311. [PMID: 31265816 PMCID: PMC6702034 DOI: 10.1016/j.brainres.2019.146311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/15/2019] [Accepted: 06/27/2019] [Indexed: 10/26/2022]
Abstract
The ventromedial hypothalamic nucleus (VMN) is a vital component of the neural circuitry that regulates glucostasis. Norepinephrine (NE) controls VMN gluco-inhibitory γ-aminobutyric acid (GABA) and gluco-stimulatory nitric oxide (NO) transmission. Sex-specific insulin-induced hypoglycemic (IIH) patterns of VMN GABA signaling are estrogen receptor-alpha (ERα)- and -beta (ERβ)-dependent. Current research utilized combinatory immunocytochemistry, laser-microdissection, and Western blot techniques in a pharmacological approach to address the hypothesis that ERα and/or -β mediate sex-dimorphic VMN GABAergic and/or nitrergic nerve cell receptivity to NE and estradiol during IIH. The impact of these ER on expression of the pyruvate recycling pathway marker proteins glutaminase (GLS) and malic enzyme-1 (ME-1) was also examined. Both VMN neuron populations express ERα, ERβ, and G protein-coupled estrogen receptor-1 (GPER), along with alpha1, alpha2, and beta1 adrenergic receptor (AR) proteins. NO neurons exhibited ERα/β-dependent (beta1 AR, GPER) and -independent (alpha1 AR) sex differences in receptor protein responses to hypoglycemia. Similarly, sex-dimorphic effects of IIH on alpha1 AR, alpha2 AR, and ERα profiles in GABA neurons involve ERα/β. These ERs also underlie divergent adjustments in gluco-regulatory nerve cell GLS and ME-1 protein expression in hypoglycemic males and females. Sex-specific nitrergic and GABAergic nerve cell sensitivity to NE and E, respectively, during IIH may contribute to sex-contingent patterns of neurotransmitter signaling.
Collapse
Affiliation(s)
- M Main Uddin
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - A S M Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States.
| |
Collapse
|
34
|
Briski KP, Mandal SK. Hindbrain lactoprivic regulation of hypothalamic neuron transactivation and gluco-regulatory neurotransmitter expression: Impact of antecedent insulin-induced hypoglycemia. Neuropeptides 2019; 77:101962. [PMID: 31488323 PMCID: PMC6756167 DOI: 10.1016/j.npep.2019.101962] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/27/2019] [Accepted: 08/27/2019] [Indexed: 12/18/2022]
Abstract
Hindbrain energy state shapes hypothalamic control of glucostasis. Dorsal vagal complex (DVC) L-lactate deficiency is a potent glucose-stimulatory signal that triggers neuronal transcriptional activation in key hypothalamic metabolic loci. The energy gauge AMPK is activated in DVC metabolic-sensory A2 noradrenergic neurons by hypoglycemia-associated lactoprivation, but sensor reactivity is diminished by antecedent hypoglycemia (AH). Current research addressed the premise that AH alters hindbrain lactoprivic regulation of hypothalamic metabolic transmitter function. AH did not modify reductions in A2 dopamine-beta-hydroxylase and monocarboxylate-2 (MCT2) protein expression elicited by caudal fourth ventricular delivery of the MCT inhibitor alpha-cyano-4-hydroxycinnamic acid (4CIN), but attenuated 4CIN activation of A2 AMPK. 4CIN constraint of hypothalamic norepinephrine (NE) activity was averted by AH in a site-specific manner. 4CIN induction of Fos immunolabeling in hypothalamic arcuate (ARH), ventromedial (VMN), dorsomedial (DMN) and paraventricular (PVN) nuclei and lateral hypothalamic area (LHA) was avoided by AH. AH affected reactivity of select hypothalamic metabolic neurotransmitter/enzyme marker proteins, e.g. ARH neuropeptide Y, VMN glutamate decarboxylase, DMN RFamide-related peptide-1 and -3, and LHA orexin-A profiles to 4CIN, but did not alleviate drug inhibition of ARH proopiomelanocortin. AH prevented 4CIN augmentation of circulating glucagon, but did not alter hyperglycemic or hypocorticosteronemic responses to that treatment. Results identify hindbrain lactate deficiency as a stimulus for glucagon secretion, and imply that habituation of this critical counter-regulatory hormone to recurring hypoglycemia may involve one or more hypothalamic neurotransmitters characterized here by acclimation to this critical sensory stimulus.
Collapse
Affiliation(s)
- Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States of America.
| | - Santosh K Mandal
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71201, United States of America
| |
Collapse
|
35
|
Farhat R, Su G, Sejling AS, Knight N, Fisher SJ, Chan O. Carvedilol prevents counterregulatory failure and impaired hypoglycaemia awareness in non-diabetic recurrently hypoglycaemic rats. Diabetologia 2019; 62:676-686. [PMID: 30627753 PMCID: PMC6403018 DOI: 10.1007/s00125-018-4802-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/28/2018] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS This study evaluates whether the non-selective β-blocker, carvedilol, can be used to prevent counterregulatory failure and the development of impaired awareness of hypoglycaemia (IAH) in recurrently hypoglycaemic rats. METHODS Sprague Dawley rats were implanted with vascular catheters and intracranial guide cannulas targeting the ventromedial hypothalamus (VMH). These animals underwent either three bouts of insulin-induced hypoglycaemia or received three saline injections (control group) over 3 days. A subgroup of recurrently hypoglycaemic animals was treated with carvedilol. The next day, the animals underwent a hypoglycaemic clamp with microdialysis without carvedilol treatment to evaluate changes in central lactate and hormone levels. To assess whether carvedilol prevented IAH, we treated rats that had received repeated 2-deoxyglucose (2DG) injections to impair their awareness of hypoglycaemia with carvedilol and measured food intake in response to insulin-induced hypoglycaemia as a surrogate marker for hypoglycaemia awareness. RESULTS Compared with the control group, recurrently hypoglycaemic rats had a ~1.7-fold increase in VMH lactate and this was associated with a 75% reduction in the sympathoadrenal response to hypoglycaemia. Treatment with carvedilol restored VMH lactate levels and improved the adrenaline (epinephrine) responses. In 2DG-treated rats compared with control animals receiving saline, food intake was reduced in response to hypoglycaemia and increased with carvedilol treatment. CONCLUSIONS/INTERPRETATION We conclude that carvedilol may be a useful therapy to prevent counterregulatory failure and improve IAH.
Collapse
Affiliation(s)
- Rawad Farhat
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Gong Su
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
- Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | | | - Nicholas Knight
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Simon J Fisher
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA
| | - Owen Chan
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, University of Utah, Department 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, UT, 84112, USA.
| |
Collapse
|
36
|
Hasan Mahmood ASM, Mandal SK, Bheemanapally K, Ibrahim MMH, Briski KP. Norepinephrine control of ventromedial hypothalamic nucleus glucoregulatory neurotransmitter expression in the female rat: Role of monocarboxylate transporter function. Mol Cell Neurosci 2019; 95:51-58. [PMID: 30660767 PMCID: PMC6472905 DOI: 10.1016/j.mcn.2019.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/09/2019] [Accepted: 01/16/2019] [Indexed: 12/20/2022] Open
Abstract
The ventromedial hypothalamic nucleus (VMN) is a critical component of the neural circuitry that regulates glucostasis. Astrocyte glycogen is a vital reserve of glucose and its oxidizable metabolite L-lactate. In hypoglycemic female rats, estradiol-dependent augmentation of VMN glycogen phosphorylase (GP) protein requires hindbrain catecholamine input. Research here investigated the premise that norepinephrine (NE) regulation of VMN astrocyte metabolism shapes local glucoregulatory neurotransmitter signaling in this sex. Estradiol-implanted ovariectomized rats were pretreated by intra-VMN administration of the monocarboxylate transporter inhibitor alpha-cyano-4-hydroxy-cinnamic acid (4CIN) or vehicle before NE delivery to that site. NE caused 4CIN-reversible reduction or augmentation of VMN glycogen synthase and phosphorylase expression. 4CIN prevented NE stimulation of gluco-inhibitory (glutamate decarboxylase65/67) and suppression of gluco-stimulatory (neuronal nitric oxide synthase) neuron marker proteins. These outcomes imply that effects of noradrenergic stimulation of VMN astrocyte glycogen depletion on glucoregulatory transmitter signaling may be mediated, in part, by glycogen-derived substrate fuel provision. NE control of astrocyte glycogen metabolism may involve down-regulated adrenoreceptor (AR), e.g. alpha1 and alpha2, alongside amplified beta1 AR and estrogen receptor-beta signaling. Noradrenergic hypoglycemia was refractory to 4CIN, implying that additional NE-sensitive VMN glucoregulatory neurochemicals may be insensitive to monocarboxylate uptake. Augmentation of circulating free fatty acids by combinatory NE and 4CIN, but not NE alone implies that acute hypoglycemia induced here is an insufficient stimulus for mobilization of these fuels, but is adequate when paired with diminished brain monocarboxylate fuel availability.
Collapse
Affiliation(s)
- A S M Hasan Mahmood
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States of America
| | - Santosh K Mandal
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States of America
| | - Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States of America
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States of America
| | - K P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, United States of America.
| |
Collapse
|
37
|
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] [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.
Collapse
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
| |
Collapse
|
38
|
Agrawal R, Vieira-de-Abreu A, Durupt G, Taylor C, Chan O, Fisher SJ. Insulin regulates GLUT4 in the ventromedial hypothalamus to restore the sympathoadrenal response to hypoglycemia in diabetic rats. Am J Physiol Endocrinol Metab 2018; 315:E1286-E1295. [PMID: 30226996 PMCID: PMC6336954 DOI: 10.1152/ajpendo.00324.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is proposed that the impaired counterregulatory response (CRR) to hypoglycemia in insulin-deficient diabetes may be due to chronic brain insulin deficiency. To test this hypothesis, streptozotocin-induced diabetic Sprague-Dawley rats were infused with insulin (3 mU/day) or artificial cerebrospinal fluid (aCSF) bilaterally into the ventromedial hypothalamus (VMH) for 2 wk and compared with nondiabetic rats. Rats underwent hyperinsulinemic (50 mU·kg-1·min-1)-hypoglycemic (~45 mg/dl) clamps. Diabetic rats demonstrated an impaired CRR to hypoglycemia, noted by a high glucose infusion rate and blunted epinephrine and glucagon responses. The defective sympathoadrenal response was restored by chronic infusion of insulin into the VMH. Diabetic rats had decreased VMH Akt phosphorylation and decreased VMH glucose transporter 4 (GLUT4) content, which was also restored by chronic infusion of insulin into the VMH. Separate experiments in nondiabetic rats in which GLUT4 translocation into the VMH was inhibited with an infusion of indinavir were notable for an impaired CRR to hypoglycemia, indicated by increased glucose infusion rate and diminished epinephrine and glucagon responses. Results suggest that, in this model of diabetes, VMH insulin deficiency impairs the sympathoadrenal response to hypoglycemia and that chronic infusion of insulin into the VMH is sufficient to normalize the sympathoadrenal response to hypoglycemia via restoration of GLUT4 expression in the VMH.
Collapse
Affiliation(s)
- Rahul Agrawal
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| | - Adriana Vieira-de-Abreu
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| | - Griffin Durupt
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| | - Casey Taylor
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| | - Owen Chan
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| | - Simon J Fisher
- Division of Endocrinology, Metabolism, and Diabetes, University of Utah School of Medicine , Salt Lake City, Utah
| |
Collapse
|
39
|
Jin S, Diano S. Mitochondrial Dynamics and Hypothalamic Regulation of Metabolism. Endocrinology 2018; 159:3596-3604. [PMID: 30203064 PMCID: PMC6157417 DOI: 10.1210/en.2018-00667] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/02/2018] [Indexed: 01/22/2023]
Abstract
Mitochondria are cellular organelles that play an important role in bioenergetic processes. In the central nervous system, high energy-demanding neurons are critically dependent on mitochondria to fulfill their appropriate functions. The hypothalamus is a key brain area for maintaining glucose and energy homeostasis via the ability of hypothalamic neurons to sense, integrate, and respond to numerous metabolic signals. Mitochondrial function has emerged as an important component in the regulation of hypothalamic neurons controlling glucose and energy homeostasis. Although the underlying mechanisms are not fully understood, emerging evidence indicates that mitochondrial dysfunction in hypothalamic neurons may contribute to the development of various metabolic diseases, including obesity and type 2 diabetes mellitus (T2DM). In this review, we summarize recent studies demonstrating the link between mitochondria and hypothalamic neural control of glucose and energy homeostasis. Finally, this review provides an insight to understand how mitochondria in hypothalamic neurons may contribute to the development of metabolic disorders, such as T2DM and obesity.
Collapse
Affiliation(s)
- Sungho Jin
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut
| | - Sabrina Diano
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Clinical Medicine and Surgery, University of Naples “Federico II,” Naples, Italy
| |
Collapse
|
40
|
Belfort-DeAguiar R, Gallezot JD, Hwang JJ, Elshafie A, Yeckel CW, Chan O, Carson RE, Ding YS, Sherwin RS. Noradrenergic Activity in the Human Brain: A Mechanism Supporting the Defense Against Hypoglycemia. J Clin Endocrinol Metab 2018; 103:2244-2252. [PMID: 29590401 PMCID: PMC6456998 DOI: 10.1210/jc.2017-02717] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/20/2018] [Indexed: 01/12/2023]
Abstract
CONTEXT Hypoglycemia, one of the major factors limiting optimal glycemic control in insulin-treated patients with diabetes, elicits a brain response to restore normoglycemia by activating counterregulation. Animal data indicate that local release of norepinephrine (NE) in the hypothalamus is important for triggering hypoglycemia-induced counterregulatory (CR) hormonal responses. OBJECTIVE To examine the potential role of brain noradrenergic (NA) activation in humans during hypoglycemia. DESIGN A hyperinsulinemic-hypoglycemic clamp was performed in conjunction with positron emission tomographic imaging. PARTICIPANTS Nine lean healthy volunteers were studied during the hyperinsulinemic-hypoglycemic clamp. DESIGN Participants received intravenous injections of (S,S)-[11C]O-methylreboxetine ([11C]MRB), a highly selective NE transporter (NET) ligand, at baseline and during hypoglycemia. RESULTS Hypoglycemia increased plasma epinephrine, glucagon, cortisol, and growth hormone and decreased [11C]MRB binding potential (BPND) by 24% ± 12% in the raphe nucleus (P < 0.01). In contrast, changes in [11C]MRB BPND in the hypothalamus positively correlated with increments in epinephrine and glucagon levels and negatively correlated with glucose infusion rate (all P < 0.05). Furthermore, in rat hypothalamus studies, hypoglycemia induced NET translocation from the cytosol to the plasma membrane. CONCLUSIONS Insulin-induced hypoglycemia initiated a complex brain NA response in humans. Raphe nuclei, a region involved in regulating autonomic output, motor activity, and hunger, had increased NA activity, whereas the hypothalamus showed a NET-binding pattern that was associated with the individual's CR response magnitude. These findings suggest that NA output most likely is important for modulating brain responses to hypoglycemia in humans.
Collapse
Affiliation(s)
- Renata Belfort-DeAguiar
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut
- Correspondence and Reprint Requests: Renata Belfort-DeAguiar, MD, PhD, 300 Cedar Street, TAC S135, New Haven, Connecticut 06520. E-mail:
| | | | - Janice J Hwang
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut
| | - Ahmed Elshafie
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut
| | - Catherine W Yeckel
- Yale School of Public Health, Yale School of Medicine, New Haven, Connecticut
| | - Owen Chan
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah
| | - Richard E Carson
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut
| | - Yu-Shin Ding
- Department of Radiology, New York University Medical Center, New York, New York
| | - Robert S Sherwin
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut
| |
Collapse
|
41
|
Khodai T, Nunn N, Worth AA, Feetham CH, Belle MDC, Piggins HD, Luckman SM. PACAP Neurons in the Ventromedial Hypothalamic Nucleus Are Glucose Inhibited and Their Selective Activation Induces Hyperglycaemia. Front Endocrinol (Lausanne) 2018; 9:632. [PMID: 30425681 PMCID: PMC6218416 DOI: 10.3389/fendo.2018.00632] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/05/2018] [Indexed: 01/22/2023] Open
Abstract
Background: Glucose-sensing neurons are located in several parts of the brain, but are concentrated in the ventromedial nucleus of the hypothalamus (VMH). The importance of these VMH neurons in glucose homeostasis is well-established, however, little is known about their individual identity. In the present study, we identified a distinct glucose-sensing population in the VMH and explored its place in the glucose-regulatory network. Methods: Using patch-clamp electrophysiology on Pacap-cre::EYFP cells, we explored the glucose-sensing ability of the pituitary adenylate cyclase-activating peptide (PACAP) neurons both inside and outside the VMH. We also mapped the efferent projections of these neurons using anterograde and retrograde tracing techniques. Finally, to test the functionality of PACAPVMH in vivo, we used DREADD technology and measured systemic responses. Results: We demonstrate that PACAP neurons inside (PACAPVMH), but not outside the VMH are intrinsically glucose inhibited (GI). Anatomical tracing techniques show that PACAPVMH neurons project to several areas that can influence autonomic output. In vivo, chemogenetic stimulation of these neurons inhibits insulin secretion leading to reduced glucose tolerance, implicating their role in systemic glucose regulation. Conclusion: These findings are important as they identify, for the first time, a specific VMH neuronal population involved in glucose homeostasis. Identifying the different glucose-sensing populations in the VMH will help piece together the different arms of glucose regulation providing vital information regarding central responses to glucose metabolic disorders including hypoglycaemia.
Collapse
Affiliation(s)
- Tansi Khodai
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nicolas Nunn
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Amy A. Worth
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Claire H. Feetham
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | | | - Hugh D. Piggins
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Simon M. Luckman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- *Correspondence: Simon M. Luckman
| |
Collapse
|
42
|
Abstract
A hypercaloric diet combined with a sedentary lifestyle is a major risk factor for the development of insulin resistance, type 2 diabetes mellitus (T2DM) and associated comorbidities. Standard treatment for T2DM begins with lifestyle modification, and includes oral medications and insulin therapy to compensate for progressive β-cell failure. However, current pharmaceutical options for T2DM are limited in that they do not maintain stable, durable glucose control without the need for treatment intensification. Furthermore, each medication is associated with adverse effects, which range from hypoglycaemia to weight gain or bone loss. Unexpectedly, fibroblast growth factor 1 (FGF1) and its low mitogenic variants have emerged as potentially safe candidates for restoring euglycaemia, without causing overt adverse effects. In particular, a single peripheral injection of FGF1 can lower glucose to normal levels within hours, without the risk of hypoglycaemia. Similarly, a single intracerebroventricular injection of FGF1 can induce long-lasting remission of the diabetic phenotype. This Review discusses potential mechanisms by which centrally administered FGF1 improves central glucose-sensing and peripheral glucose uptake in a sustained manner. Specifically, we explore the potential crosstalk between FGF1 and glucose-sensing neuronal circuits, hypothalamic neural stem cells and synaptic plasticity. Finally, we highlight therapeutic considerations of FGF1 and compare its metabolic actions with FGF15 (rodents), FGF19 (humans) and FGF21.
Collapse
Affiliation(s)
- Emanuel Gasser
- Gene Expression Laboratory, Salk Institute for Biological Studies
| | - Christopher P Moutos
- Gene Expression Laboratory, Salk Institute for Biological Studies
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
- College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Studies
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA
| |
Collapse
|
43
|
Glucose Sensing by Skeletal Myocytes Couples Nutrient Signaling to Systemic Homeostasis. Mol Cell 2017; 66:332-344.e4. [PMID: 28475869 PMCID: PMC5489118 DOI: 10.1016/j.molcel.2017.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 02/07/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022]
Abstract
Skeletal muscle is a major site of postprandial glucose disposal. Inadequate insulin action in skeletal myocytes contributes to hyperglycemia in diabetes. Although glucose is known to stimulate insulin secretion by β cells, whether it directly engages nutrient signaling pathways in skeletal muscle to maintain systemic glucose homeostasis remains largely unexplored. Here we identified the Baf60c-Deptor-AKT pathway as a target of muscle glucose sensing that augments insulin action in skeletal myocytes. Genetic activation of this pathway improved postprandial glucose disposal in mice, whereas its muscle-specific ablation impaired insulin action and led to postprandial glucose intolerance. Mechanistically, glucose triggers KATP channel-dependent calcium signaling, which promotes HDAC5 phosphorylation and nuclear exclusion, leading to Baf60c induction and insulin-independent AKT activation. This pathway is engaged by the anti-diabetic sulfonylurea drugs to exert their full glucose-lowering effects. These findings uncover an unexpected mechanism of glucose sensing in skeletal myocytes that contributes to homeostasis and therapeutic action.
Collapse
|
44
|
Picard A, Soyer J, Berney X, Tarussio D, Quenneville S, Jan M, Grouzmann E, Burdet F, Ibberson M, Thorens B. A Genetic Screen Identifies Hypothalamic Fgf15 as a Regulator of Glucagon Secretion. Cell Rep 2016; 17:1795-1806. [PMID: 27829151 PMCID: PMC5120348 DOI: 10.1016/j.celrep.2016.10.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 12/26/2022] Open
Abstract
The counterregulatory response to hypoglycemia, which restores normal blood glucose levels to ensure sufficient provision of glucose to the brain, is critical for survival. To discover underlying brain regulatory systems, we performed a genetic screen in recombinant inbred mice for quantitative trait loci (QTL) controlling glucagon secretion in response to neuroglucopenia. We identified a QTL on the distal part of chromosome 7 and combined this genetic information with transcriptomic analysis of hypothalami. This revealed Fgf15 as the strongest candidate to control the glucagon response. Fgf15 was expressed by neurons of the dorsomedial hypothalamus and the perifornical area. Intracerebroventricular injection of FGF19, the human ortholog of Fgf15, reduced activation by neuroglucopenia of dorsal vagal complex neurons, of the parasympathetic nerve, and lowered glucagon secretion. In contrast, silencing Fgf15 in the dorsomedial hypothalamus increased neuroglucopenia-induced glucagon secretion. These data identify hypothalamic Fgf15 as a regulator of glucagon secretion.
Collapse
Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Josselin Soyer
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Simon Quenneville
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Maxime Jan
- Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Eric Grouzmann
- Service de Biomédicine, Laboratoire des Catécholamines et Peptides, Centre Hospitalier Universitaire Vaudois CHUV, 1011 Lausanne, Switzerland
| | - Frédéric Burdet
- Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Mark Ibberson
- Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| |
Collapse
|
45
|
Xu Y, Tong Q. Central leptin action on euglycemia restoration in type 1 diabetes: Restraining responses normally induced by fasting? Int J Biochem Cell Biol 2016; 88:198-203. [PMID: 27702650 DOI: 10.1016/j.biocel.2016.09.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/27/2016] [Accepted: 09/30/2016] [Indexed: 01/29/2023]
Abstract
Leptin monotherapy is sufficient to restore euglycemia in insulinopenic type 1 diabetes (T1D), yet the underlying mechanism remains poorly understood. Accumulating evidence demonstrates that the brain mediates the leptin action on euglycemia restoration. Here, we first review evidence supporting that symptoms in T1D resemble an uncontrolled response to fasting. Then, we discuss recent research progress on brain neurons and their neurotransmitters that potentially mediate the leptin action. Finally, peripheral effective pathways, which are normally involved in fasting responses and associated with leptin action on euglycemia restoration in T1D, will also be discussed. This summary complements several previous excellent reviews on this topic (Meek and Morton, 2016; Perry et al., 2016; Fujikawa and Coppari, 2015). A deep understanding of neurocircuitry and the peripheral effective pathways that mediate the leptin action on euglycemia restoration will likely lead to novel targets for an insulin-independent therapeutics against T1D.
Collapse
Affiliation(s)
- Yuanzhong Xu
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, The University of Texas Health Science Center at Houston, United States
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, The University of Texas Health Science Center at Houston, United States.
| |
Collapse
|
46
|
Steinbusch LKM, Picard A, Bonnet MS, Basco D, Labouèbe G, Thorens B. Sex-Specific Control of Fat Mass and Counterregulation by Hypothalamic Glucokinase. Diabetes 2016; 65:2920-31. [PMID: 27422385 DOI: 10.2337/db15-1514] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 07/07/2016] [Indexed: 11/13/2022]
Abstract
Glucokinase (Gck) is a critical regulator of glucose-induced insulin secretion by pancreatic β-cells. It has been suggested to also play an important role in glucose signaling in neurons of the ventromedial hypothalamic nucleus (VMN), a brain nucleus involved in the control of glucose homeostasis and feeding. To test the role of Gck in VMN glucose sensing and physiological regulation, we studied mice with genetic inactivation of the Gck gene in Sf1 neurons of the VMN (Sf1Gck(-/-) mice). Compared with control littermates, Sf1Gck(-/-) mice displayed increased white fat mass and adipocyte size, reduced lean mass, impaired hypoglycemia-induced glucagon secretion, and a lack of parasympathetic and sympathetic nerve activation by neuroglucopenia. However, these phenotypes were observed only in female mice. To determine whether Gck was required for glucose sensing by Sf1 neurons, we performed whole-cell patch clamp analysis of brain slices from control and Sf1Gck(-/-) mice. Absence of Gck expression did not prevent the glucose responsiveness of glucose-excited or glucose-inhibited Sf1 neurons in either sex. Thus Gck in the VMN plays a sex-specific role in the glucose-dependent control of autonomic nervous activity; this is, however, unrelated to the control of the firing activity of classical glucose-responsive neurons.
Collapse
Affiliation(s)
| | - Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Marion S Bonnet
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Gwenaël Labouèbe
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
47
|
Leclair E, Liggins RT, Peckett AJ, Teich T, Coy DH, Vranic M, Riddell MC. Glucagon responses to exercise-induced hypoglycaemia are improved by somatostatin receptor type 2 antagonism in a rat model of diabetes. Diabetologia 2016; 59:1724-31. [PMID: 27075449 DOI: 10.1007/s00125-016-3953-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/18/2016] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESIS Regular exercise is at the cornerstone of care in type 1 diabetes. However, relative hyperinsulinaemia and a blunted glucagon response to exercise promote hypoglycaemia. Recently, a selective antagonist of somatostatin receptor 2, PRL-2903, was shown to improve glucagon counterregulation to hypoglycaemia in resting streptozotocin-induced diabetic rats. The aim of this study was to test the efficacy of PRL-2903 in enhancing glucagon counterregulation during repeated hyperinsulinaemic exercise. METHODS Diabetic rats performed daily exercise for 1 week and were then exposed to saline (154 mmol/l NaCl) or PRL-2903, 10 mg/kg, before hyperinsulinaemic exercise on two separate occasions spaced 1 day apart. In the following week, animals crossed over to the alternate treatment for a third hyperinsulinaemic exercise protocol. RESULTS Liver glycogen content was lower in diabetic rats compared with control rats, despite daily insulin therapy (p < 0.05). Glucagon levels failed to increase during exercise with saline but increased three-to-six fold with PRL-2903 (all p < 0.05). Glucose concentrations tended to be higher during exercise and early recovery with PRL-2903 on both days of treatment; this difference did not achieve statistical significance (p > 0.05). CONCLUSIONS/INTERPRETATION PRL-2903 improves glucagon counterregulation during exercise. However, liver glycogen stores or other factors limit the prevention of exercise-induced hypoglycaemia in rats with streptozotocin-induced diabetes.
Collapse
Affiliation(s)
- Erwan Leclair
- School of Kinesiology and Health Science, York University, Toronto, ON, M3J 1P3, Canada
| | | | - Ashley J Peckett
- School of Kinesiology and Health Science, York University, Toronto, ON, M3J 1P3, Canada
| | - Trevor Teich
- School of Kinesiology and Health Science, York University, Toronto, ON, M3J 1P3, Canada
| | - David H Coy
- Department of Medicine, Peptide Research Labs, Tulane University Medical Center, New Orleans, LA, USA
| | - Mladen Vranic
- Departments of Physiology and Medicine, University of Toronto, Toronto, ON, Canada
| | - Michael C Riddell
- School of Kinesiology and Health Science, York University, Toronto, ON, M3J 1P3, Canada.
| |
Collapse
|
48
|
UCP2 Regulates Mitochondrial Fission and Ventromedial Nucleus Control of Glucose Responsiveness. Cell 2016; 164:872-83. [PMID: 26919426 DOI: 10.1016/j.cell.2016.02.010] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/08/2015] [Accepted: 02/03/2016] [Indexed: 01/21/2023]
Abstract
The ventromedial nucleus of the hypothalamus (VMH) plays a critical role in regulating systemic glucose homeostasis. How neurons in this brain area adapt to the changing metabolic environment to regulate circulating glucose levels is ill defined. Here, we show that glucose load results in mitochondrial fission and reduced reactive oxygen species in VMH neurons mediated by dynamin-related peptide 1 (DRP1) under the control of uncoupling protein 2 (UCP2). Probed by genetic manipulations and chemical-genetic control of VMH neuronal circuitry, we unmasked that this mitochondrial adaptation determines the size of the pool of glucose-excited neurons in the VMH and that this process regulates systemic glucose homeostasis. Thus, our data unmasked a critical cellular biological process controlled by mitochondrial dynamics in VMH regulation of systemic glucose homeostasis.
Collapse
|
49
|
The ventromedial hypothalamus oxytocin induces locomotor behavior regulated by estrogen. Physiol Behav 2016; 164:107-12. [PMID: 27237044 DOI: 10.1016/j.physbeh.2016.05.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 01/06/2023]
Abstract
Our previous studies demonstrated that excitation of neurons in the rat ventromedial hypothalamus (VMH) induced locomotor activity. An oxytocin receptor (Oxtr) exists in the VMH and plays a role in regulating sexual behavior. However, the role of Oxtr in the VMH in locomotor activity is not clear. In this study we examined the roles of oxytocin in the VMH in running behavior, and also investigated the involvement of estrogen in this behavioral change. Microinjection of oxytocin into the VMH induced a dose-dependent increase in the running behavior in male rats. The oxytocin-induced running activity was inhibited by simultaneous injection of Oxtr-antagonist, (d(CH2)5(1), Try(Me)(2), Orn(8))-oxytocin. Oxytocin injection also induced running behavior in ovariectomized (OVX) female rats. Pretreatment of the OVX rats with estrogen augmented the oxytocin-induced running activity twofold, and increased the Oxtr mRNA in the VMH threefold. During the estrus cycle locomotor activity spontaneously increased in the dark period of proestrus. The Oxtr mRNA was up-regulated in the proestrus afternoon. Blockade of oxytocin neurotransmission by its antagonist before the onset of the dark period of proestrus decreased the following nocturnal locomotor activity. These findings demonstrate that Oxtr in the VMH is involved in the induction of running behavior and that estrogen facilitates this effect by means of Oxtr up-regulation, suggesting the involvement of oxytocin in the locomotor activity of proestrus female rats.
Collapse
|
50
|
Rijnsburger M, Belegri E, Eggels L, Unmehopa UA, Boelen A, Serlie MJ, la Fleur SE. The effect of diet interventions on hypothalamic nutrient sensing pathways in rodents. Physiol Behav 2016; 162:61-8. [PMID: 27083123 DOI: 10.1016/j.physbeh.2016.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/25/2016] [Accepted: 04/07/2016] [Indexed: 12/13/2022]
Abstract
The hypothalamus plays a fundamental role in regulating homeostatic processes including regulation of food intake. Food intake is driven in part by energy balance, which is sensed by specific brain structures through signaling molecules such as nutrients and hormones. Both circulating glucose and fatty acids decrease food intake via a central mechanism involving the hypothalamus and brain stem. Besides playing a role in signaling energy status, glucose and fatty acids serve as fuel for neurons. This review focuses on the effects of glucose and fatty acids on hypothalamic pathways involved in regulation of energy metabolism as well as on the role of the family of peroxisome proliferator activated receptors (PPARs) which are implicated in regulation of central energy homeostasis. We further discuss the effects of different hypercaloric diets on these pathways.
Collapse
Affiliation(s)
- Merel Rijnsburger
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Evita Belegri
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Leslie Eggels
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Unga A Unmehopa
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Mireille J Serlie
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands
| | - Susanne E la Fleur
- Department of Endocrinology & Metabolism, Academic Medical Center, Amsterdam, The Netherlands.
| |
Collapse
|