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Thorens B. Neuronal glucose sensing mechanisms and circuits in the control of insulin and glucagon secretion. Physiol Rev 2024; 104:1461-1486. [PMID: 38661565 DOI: 10.1152/physrev.00038.2023] [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: 09/29/2023] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 04/26/2024] Open
Abstract
Glucose homeostasis is mainly under the control of the pancreatic islet hormones insulin and glucagon, which, respectively, stimulate glucose uptake and utilization by liver, fat, and muscle and glucose production by the liver. The balance between the secretions of these hormones is under the control of blood glucose concentrations. Indeed, pancreatic islet β-cells and α-cells can sense variations in glycemia and respond by an appropriate secretory response. However, the secretory activity of these cells is also under multiple additional metabolic, hormonal, and neuronal signals that combine to ensure the perfect control of glycemia over a lifetime. The central nervous system (CNS), which has an almost absolute requirement for glucose as a source of metabolic energy and thus a vital interest in ensuring that glycemic levels never fall below ∼5 mM, is equipped with populations of neurons responsive to changes in glucose concentrations. These neurons control pancreatic islet cell secretion activity in multiple ways: through both branches of the autonomic nervous system, through the hypothalamic-pituitary-adrenal axis, and by secreting vasopressin (AVP) in the blood at the level of the posterior pituitary. Here, we present the autonomic innervation of the pancreatic islets; the mechanisms of neuron activation by a rise or a fall in glucose concentration; how current viral tracing, chemogenetic, and optogenetic techniques allow integration of specific glucose sensing neurons in defined neuronal circuits that control endocrine pancreas function; and, finally, how genetic screens in mice can untangle the diversity of the hypothalamic mechanisms controlling the response to hypoglycemia.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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2
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Shigapova RR, Mukhamedshina YO. Electrophysiology Methods for Assessing of Neurodegenerative and Post-Traumatic Processes as Applied to Translational Research. Life (Basel) 2024; 14:737. [PMID: 38929721 PMCID: PMC11205106 DOI: 10.3390/life14060737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
Electrophysiological studies have long established themselves as reliable methods for assessing the functional state of the brain and spinal cord, the degree of neurodegeneration, and evaluating the effectiveness of therapy. In addition, they can be used to diagnose, predict functional outcomes, and test the effectiveness of therapeutic and rehabilitation programs not only in clinical settings, but also at the preclinical level. Considering the urgent need to develop potential stimulators of neuroregeneration, it seems relevant to obtain objective data when modeling neurological diseases in animals. Thus, in the context of the application of electrophysiological methods, not only the comparison of the basic characteristics of bioelectrical activity of the brain and spinal cord in humans and animals, but also their changes against the background of neurodegenerative and post-traumatic processes are of particular importance. In light of the above, this review will contribute to a better understanding of the results of electrophysiological assessment in neurodegenerative and post-traumatic processes as well as the possibility of translating these methods from model animals to humans.
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Affiliation(s)
- Rezeda Ramilovna Shigapova
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan 420008, Russia;
| | - Yana Olegovna Mukhamedshina
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan 420008, Russia;
- Department of Histology, Cytology and Embryology, Kazan State Medical University, Kazan 420012, Russia
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3
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Thapaliya B, Ray B, Farahdel B, Suresh P, Sapkota R, Holla B, Mahadevan J, Chen J, Vaidya N, Perrone-Bizzozero NI, Benegal V, Schumann G, Calhoun VD, Liu J. Cross-continental environmental and genome-wide association study on children and adolescent anxiety and depression. Front Psychiatry 2024; 15:1384298. [PMID: 38827440 PMCID: PMC11141390 DOI: 10.3389/fpsyt.2024.1384298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/17/2024] [Indexed: 06/04/2024] Open
Abstract
Anxiety and depression in children and adolescents warrant special attention as a public health concern given their devastating and long-term effects on development and mental health. Multiple factors, ranging from genetic vulnerabilities to environmental stressors, influence the risk for the disorders. This study aimed to understand how environmental factors and genomics affect children and adolescents anxiety and depression across three cohorts: Adolescent Brain and Cognitive Development Study (US, age of 9-10; N=11,875), Consortium on Vulnerability to Externalizing Disorders and Addictions (INDIA, age of 6-17; N=4,326) and IMAGEN (EUROPE, age of 14; N=1888). We performed data harmonization and identified the environmental impact on anxiety/depression using a linear mixed-effect model, recursive feature elimination regression, and the LASSO regression model. Subsequently, genome-wide association analyses with consideration of significant environmental factors were performed for all three cohorts by mega-analysis and meta-analysis, followed by functional annotations. The results showed that multiple environmental factors contributed to the risk of anxiety and depression during development, where early life stress and school support index had the most significant and consistent impact across all three cohorts. In both meta, and mega-analysis, SNP rs79878474 in chr11p15 emerged as a particularly promising candidate associated with anxiety and depression, despite not reaching genomic significance. Gene set analysis on the common genes mapped from top promising SNPs of both meta and mega analyses found significant enrichment in regions of chr11p15 and chr3q26, in the function of potassium channels and insulin secretion, in particular Kv3, Kir-6.2, SUR potassium channels encoded by the KCNC1, KCNJ11, and ABCCC8 genes respectively, in chr11p15. Tissue enrichment analysis showed significant enrichment in the small intestine, and a trend of enrichment in the cerebellum. Our findings provide evidences of consistent environmental impact from early life stress and school support index on anxiety and depression during development and also highlight the genetic association between mutations in potassium channels, which support the stress-depression connection via hypothalamic-pituitary-adrenal axis, along with the potential modulating role of potassium channels.
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Affiliation(s)
- Bishal Thapaliya
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Bhaskar Ray
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Britny Farahdel
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Pranav Suresh
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Ram Sapkota
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Bharath Holla
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Jayant Mahadevan
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Jiayu Chen
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
| | - Nilakshi Vaidya
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore, India
- Centre for Population Neuroscience and Stratified Medicine, Department of Psychiatry and Neuroscience, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Vivek Benegal
- Centre for Addiction Medicine, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Gunter Schumann
- Centre for Population Neuroscience and Stratified Medicine, Department of Psychiatry and Neuroscience, Charité Universitätsmedizin Berlin, Berlin, Germany
- Centre for Population Neuroscience and Precision Medicine, Institute for Science and Technology of Brain-inspired Intelligence, Fudan University, Shanghai, China
| | - Vince D. Calhoun
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Jingyu Liu
- Tri-Institutional Center for Translational Research in NeuroImaging and Data Science, Atlanta, GA, United States
- Department of Computer Science, Georgia State University, Atlanta, GA, United States
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4
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Ang MY, Takeuchi F, Kato N. Deciphering the genetic landscape of obesity: a data-driven approach to identifying plausible causal genes and therapeutic targets. J Hum Genet 2023; 68:823-833. [PMID: 37620670 PMCID: PMC10678330 DOI: 10.1038/s10038-023-01189-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/08/2023] [Accepted: 08/15/2023] [Indexed: 08/26/2023]
Abstract
OBJECTIVES Genome-wide association studies (GWAS) have successfully revealed numerous susceptibility loci for obesity. However, identifying the causal genes, pathways, and tissues/cell types responsible for these associations remains a challenge, and standardized analysis workflows are lacking. Additionally, due to limited treatment options for obesity, there is a need for the development of new pharmacological therapies. This study aimed to address these issues by performing step-wise utilization of knowledgebase for gene prioritization and assessing the potential relevance of key obesity genes as therapeutic targets. METHODS AND RESULTS First, we generated a list of 28,787 obesity-associated SNPs from the publicly available GWAS dataset (approximately 800,000 individuals in the GIANT meta-analysis). Then, we prioritized 1372 genes with significant in silico evidence against genomic and transcriptomic data, including transcriptionally regulated genes in the brain from transcriptome-wide association studies. In further narrowing down the gene list, we selected key genes, which we found to be useful for the discovery of potential drug seeds as demonstrated in lipid GWAS separately. We thus identified 74 key genes for obesity, which are highly interconnected and enriched in several biological processes that contribute to obesity, including energy expenditure and homeostasis. Of 74 key genes, 37 had not been reported for the pathophysiology of obesity. Finally, by drug-gene interaction analysis, we detected 23 (of 74) key genes that are potential targets for 78 approved and marketed drugs. CONCLUSIONS Our results provide valuable insights into new treatment options for obesity through a data-driven approach that integrates multiple up-to-date knowledgebases.
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Affiliation(s)
- Mia Yang Ang
- Department of Clinical Genome Informatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
- Department of Gene Diagnostics and Therapeutics, Medical Genomics Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
| | - Fumihiko Takeuchi
- Department of Gene Diagnostics and Therapeutics, Medical Genomics Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Norihiro Kato
- Department of Clinical Genome Informatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Gene Diagnostics and Therapeutics, Medical Genomics Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
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Javed S, Chang YT, Cho Y, Lee YJ, Chang HC, Haque M, Lin YC, Huang WH. Smith-Magenis syndrome protein RAI1 regulates body weight homeostasis through hypothalamic BDNF-producing neurons and neurotrophin downstream signalling. eLife 2023; 12:RP90333. [PMID: 37956053 PMCID: PMC10642964 DOI: 10.7554/elife.90333] [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] [Indexed: 11/15/2023] Open
Abstract
Retinoic acid-induced 1 (RAI1) haploinsufficiency causes Smith-Magenis syndrome (SMS), a genetic disorder with symptoms including hyperphagia, hyperlipidemia, severe obesity, and autism phenotypes. RAI1 is a transcriptional regulator with a pan-neural expression pattern and hundreds of downstream targets. The mechanisms linking neural Rai1 to body weight regulation remain unclear. Here we find that hypothalamic brain-derived neurotrophic factor (BDNF) and its downstream signalling are disrupted in SMS (Rai1+/-) mice. Selective Rai1 loss from all BDNF-producing cells or from BDNF-producing neurons in the paraventricular nucleus of the hypothalamus (PVH) induced obesity in mice. Electrophysiological recordings revealed that Rai1 ablation decreased the intrinsic excitability of PVHBDNF neurons. Chronic treatment of SMS mice with LM22A-4 engages neurotrophin downstream signalling and delayed obesity onset. This treatment also partially rescued disrupted lipid profiles, insulin intolerance, and stereotypical repetitive behaviour in SMS mice. These data argue that RAI1 regulates body weight and metabolic function through hypothalamic BDNF-producing neurons and that targeting neurotrophin downstream signalling might improve associated SMS phenotypes.
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Affiliation(s)
- Sehrish Javed
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Ya-Ting Chang
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Yoobin Cho
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Yu-Ju Lee
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Hao-Cheng Chang
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Minza Haque
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Yu Cheng Lin
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
| | - Wei-Hsiang Huang
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill UniversityMontréalCanada
- Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health CentreMontréalCanada
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6
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Gando I, Becerra Flores M, Chen IS, Yang HQ, Nakamura TY, Cardozo TJ, Coetzee WA. CL-705G: a novel chemical Kir6.2-specific K ATP channel opener. Front Pharmacol 2023; 14:1197257. [PMID: 37408765 PMCID: PMC10319115 DOI: 10.3389/fphar.2023.1197257] [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: 03/30/2023] [Accepted: 06/01/2023] [Indexed: 07/07/2023] Open
Abstract
Background: KATP channels have diverse roles, including regulation of insulin secretion and blood flow, and protection against biological stress responses and are excellent therapeutic targets. Different subclasses of KATP channels exist in various tissue types due to the unique assemblies of specific pore-forming (Kir6.x) and accessory (SURx) subunits. The majority of pharmacological openers and blockers act by binding to SURx and are poorly selective against the various KATP channel subclasses. Methods and Results: We used 3D models of the Kir6.2/SUR homotetramers based on existing cryo-EM structures of channels in both the open and closed states to identify a potential agonist binding pocket in a functionally critical area of the channel. Computational docking screens of this pocket with the Chembridge Core chemical library of 492,000 drug-like compounds yielded 15 top-ranked "hits", which were tested for activity against KATP channels using patch clamping and thallium (Tl+) flux assays with a Kir6.2/SUR2A HEK-293 stable cell line. Several of the compounds increased Tl+ fluxes. One of them (CL-705G) opened Kir6.2/SUR2A channels with a similar potency as pinacidil (EC50 of 9 µM and 11 μM, respectively). Remarkably, compound CL-705G had no or minimal effects on other Kir channels, including Kir6.1/SUR2B, Kir2.1, or Kir3.1/Kir3.4 channels, or Na+ currents of TE671 medulloblastoma cells. CL-705G activated Kir6.2Δ36 in the presence of SUR2A, but not when expressed by itself. CL-705G activated Kir6.2/SUR2A channels even after PIP2 depletion. The compound has cardioprotective effects in a cellular model of pharmacological preconditioning. It also partially rescued activity of the gating-defective Kir6.2-R301C mutant that is associated with congenital hyperinsulinism. Conclusion: CL-705G is a new Kir6.2 opener with little cross-reactivity with other channels tested, including the structurally similar Kir6.1. This, to our knowledge, is the first Kir-specific channel opener.
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Affiliation(s)
- Ivan Gando
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - Manuel Becerra Flores
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - I.-Shan Chen
- Phamacology, Wakayama Medical University, Wakayama, Japan
| | - Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, China
| | | | - Timothy J. Cardozo
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - William A. Coetzee
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
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7
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Lim S, Shin S, Sung Y, Lee HE, Kim KH, Song JY, Lee GH, Aziz H, Lukianenko N, Kang DM, Boesen N, Jeong H, Abdildinova A, Lee J, Yu BY, Lim SM, Lee JS, Ryu H, Pae AN, Kim YK. Levosimendan inhibits disulfide tau oligomerization and ameliorates tau pathology in Tau P301L-BiFC mice. Exp Mol Med 2023; 55:612-627. [PMID: 36914856 PMCID: PMC10073126 DOI: 10.1038/s12276-023-00959-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/26/2022] [Accepted: 01/01/2023] [Indexed: 03/14/2023] Open
Abstract
Tau oligomers play critical roles in tau pathology and are responsible for neuronal cell death and transmitting the disease in the brain. Accordingly, preventing tau oligomerization has become an important therapeutic strategy to treat tauopathies, including Alzheimer's disease. However, progress has been slow because detecting tau oligomers in the cellular context is difficult. Working toward tau-targeted drug discovery, our group has developed a tau-BiFC platform to monitor and quantify tau oligomerization. By using the tau-BiFC platform, we screened libraries with FDA-approved and passed phase I drugs and identified levosimendan as a potent anti-tau agent that inhibits tau oligomerization. 14C-isotope labeling of levosimendan revealed that levosimendan covalently bound to tau cysteines, directly inhibiting disulfide-linked tau oligomerization. In addition, levosimendan disassembles tau oligomers into monomers, rescuing neurons from aggregation states. In comparison, the well-known anti-tau agents methylene blue and LMTM failed to protect neurons from tau-mediated toxicity, generating high-molecular-weight tau oligomers. Levosimendan displayed robust potency against tau oligomerization and rescued cognitive declines induced by tauopathy in the TauP301L-BiFC mouse model. Our data present the potential of levosimendan as a disease-modifying drug for tauopathies.
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Affiliation(s)
- Sungsu Lim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Seulgi Shin
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Yoonsik Sung
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Ha Eun Lee
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Kyu Hyeon Kim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Ji Yeon Song
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Gwan-Ho Lee
- Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Hira Aziz
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Nataliia Lukianenko
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Dong Min Kang
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Department of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Nicolette Boesen
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Hyeanjeong Jeong
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Aizhan Abdildinova
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Junghee Lee
- Boston University Alzheimer's disease Research Center and VA Boston Health care System, Boston, MA, 02130, USA
| | - Byung-Yong Yu
- Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Sang Min Lim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jun-Seok Lee
- Department of Pharmacology, Korea University College of Medicine, Seoul, 02792, Republic of Korea
| | - Hoon Ryu
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,Boston University Alzheimer's disease Research Center and Department of Neurology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Ae Nim Pae
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
| | - Yun Kyung Kim
- Center for Brain Disorders, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea. .,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea.
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8
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Hernandez CC, Gimenez LE, Dahir NS, Peisley A, Cone RD. The unique structural characteristics of the Kir 7.1 inward rectifier potassium channel: a novel player in energy homeostasis control. Am J Physiol Cell Physiol 2023; 324:C694-C706. [PMID: 36717105 PMCID: PMC10026989 DOI: 10.1152/ajpcell.00335.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 02/01/2023]
Abstract
The inward rectifier potassium channel Kir7.1, encoded by the KCNJ13 gene, is a tetramer composed of two-transmembrane domain-spanning monomers, closer in homology to Kir channels associated with potassium transport such as Kir1.1, 1.2, and 1.3. Compared with other channels, Kir7.1 exhibits small unitary conductance and low dependence on external potassium. Kir7.1 channels also show a phosphatidylinositol 4,5-bisphosphate (PIP2) dependence for opening. Accordingly, retinopathy-associated Kir7.1 mutations mapped at the binding site for PIP2 resulted in channel gating defects leading to channelopathies such as snowflake vitreoretinal degeneration and Leber congenital amaurosis in blind patients. Lately, this channel's role in energy homeostasis was reported due to the direct interaction with the melanocortin type 4 receptor (MC4R) in the hypothalamus. As this channel seems to play a multipronged role in potassium homeostasis and neuronal excitability, we will discuss what is predicted from a structural viewpoint and its possible implications for hunger control.
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Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Luis E Gimenez
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Naima S Dahir
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Alys Peisley
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Roger D Cone
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
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9
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Abstract
Pericytes, attached to the surface of capillaries, play an important role in regulating local blood flow. Using optogenetic tools and genetically encoded reporters in conjunction with confocal and multiphoton imaging techniques, the 3D structure, anatomical organization, and physiology of pericytes have recently been the subject of detailed examination. This work has revealed novel functions of pericytes and morphological features such as tunneling nanotubes in brain and tunneling microtubes in heart. Here, we discuss the state of our current understanding of the roles of pericytes in blood flow control in brain and heart, where functions may differ due to the distinct spatiotemporal metabolic requirements of these tissues. We also outline the novel concept of electro-metabolic signaling, a universal mechanistic framework that links tissue metabolic state with blood flow regulation by pericytes and vascular smooth muscle cells, with capillary KATP and Kir2.1 channels as primary sensors. Finally, we present major unresolved questions and outline how they can be addressed.
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Affiliation(s)
- Thomas A Longden
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Guiling Zhao
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ashwini Hariharan
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - W Jonathan Lederer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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10
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Lv J, Xiao X, Bi M, Tang T, Kong D, Diao M, Jiao Q, Chen X, Yan C, Du X, Jiang H. ATP-sensitive potassium channels: A double-edged sword in neurodegenerative diseases. Ageing Res Rev 2022; 80:101676. [PMID: 35724860 DOI: 10.1016/j.arr.2022.101676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/15/2022] [Accepted: 06/14/2022] [Indexed: 11/25/2022]
Abstract
ATP-sensitive potassium channels (KATP channels), a group of vital channels that link the electrical activity of the cell membrane with cell metabolism, were discovered on the ventricular myocytes of guinea pigs by Noma using the patch-clamp technique in 1983. Subsequently, KATP channels have been found to be expressed in pancreatic β cells, cardiomyocytes, skeletal muscle cells, and nerve cells in the substantia nigra (SN), hippocampus, cortex, and basal ganglia. KATP channel openers (KCOs) diazoxide, nicorandil, minoxidil, and the KATP channel inhibitor glibenclamide have been shown to have anti-hypertensive, anti-myocardial ischemia, and insulin-releasing regulatory effects. Increasing evidence has suggested that KATP channels also play roles in Alzheimer's disease (AD), Parkinson's disease (PD), vascular dementia (VD), Huntington's disease (HD) and other neurodegenerative diseases. KCOs and KATP channel inhibitors protect neurons from injury by regulating neuronal excitability and neurotransmitter release, inhibiting abnormal protein aggregation and Ca2+ overload, reducing reactive oxygen species (ROS) production and microglia activation. However, KATP channels have dual effects in some cases. In this review, we focus on the roles of KATP channels and their related openers and inhibitors in neurodegenerative diseases. This will enable us to precisely take advantage of the KATP channels and provide new ideas for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Jirong Lv
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xue Xiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Mingxia Bi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Tingting Tang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Deao Kong
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Meining Diao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Qian Jiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xi Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Chunling Yan
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xixun Du
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China.
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Medical College, Qingdao University, Qingdao, China.
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11
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Yang HQ, Echeverry FA, ElSheikh A, Gando I, Anez Arredondo S, Samper N, Cardozo T, Delmar M, Shyng SL, Coetzee WA. Subcellular trafficking and endocytic recycling of K ATP channels. Am J Physiol Cell Physiol 2022; 322:C1230-C1247. [PMID: 35508187 PMCID: PMC9169827 DOI: 10.1152/ajpcell.00099.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 11/22/2022]
Abstract
Sarcolemmal/plasmalemmal ATP-sensitive K+ (KATP) channels have key roles in many cell types and tissues. Hundreds of studies have described how the KATP channel activity and ATP sensitivity can be regulated by changes in the cellular metabolic state, by receptor signaling pathways and by pharmacological interventions. These alterations in channel activity directly translate to alterations in cell or tissue function, that can range from modulating secretory responses, such as insulin release from pancreatic β-cells or neurotransmitters from neurons, to modulating contractile behavior of smooth muscle or cardiac cells to elicit alterations in blood flow or cardiac contractility. It is increasingly becoming apparent, however, that KATP channels are regulated beyond changes in their activity. Recent studies have highlighted that KATP channel surface expression is a tightly regulated process with similar implications in health and disease. The surface expression of KATP channels is finely balanced by several trafficking steps including synthesis, assembly, anterograde trafficking, membrane anchoring, endocytosis, endocytic recycling, and degradation. This review aims to summarize the physiological and pathophysiological implications of KATP channel trafficking and mechanisms that regulate KATP channel trafficking. A better understanding of this topic has potential to identify new approaches to develop therapeutically useful drugs to treat KATP channel-related diseases.
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Affiliation(s)
- Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | | | - Assmaa ElSheikh
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Ivan Gando
- Department of Pathology, NYU School of Medicine, New York, New York
| | | | - Natalie Samper
- Department of Pathology, NYU School of Medicine, New York, New York
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - Mario Delmar
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
- Department of Medicine, NYU School of Medicine, New York, New York
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - William A Coetzee
- Department of Pathology, NYU School of Medicine, New York, New York
- Department of Neuroscience & Physiology, NYU School of Medicine, New York, New York
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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12
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Cotero V, Graf J, Miwa H, Hirschstein Z, Qanud K, Huerta TS, Tai N, Ding Y, Jimenez-Cowell K, Tomaio JN, Song W, Devarajan A, Tsaava T, Madhavan R, Wallace K, Loghin E, Morton C, Fan Y, Kao TJ, Akhtar K, Damaraju M, Barenboim L, Maietta T, Ashe J, Tracey KJ, Coleman TR, Di Carlo D, Shin D, Zanos S, Chavan SS, Herzog RI, Puleo C. Stimulation of the hepatoportal nerve plexus with focused ultrasound restores glucose homoeostasis in diabetic mice, rats and swine. Nat Biomed Eng 2022; 6:683-705. [PMID: 35361935 PMCID: PMC10127248 DOI: 10.1038/s41551-022-00870-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/18/2022] [Indexed: 12/17/2022]
Abstract
Peripheral neurons that sense glucose relay signals of glucose availability to integrative clusters of neurons in the brain. However, the roles of such signalling pathways in the maintenance of glucose homoeostasis and their contribution to disease are unknown. Here we show that the selective activation of the nerve plexus of the hepatic portal system via peripheral focused ultrasound stimulation (pFUS) improves glucose homoeostasis in mice and rats with insulin-resistant diabetes and in swine subject to hyperinsulinemic-euglycaemic clamps. pFUS modulated the activity of sensory projections to the hypothalamus, altered the concentrations of metabolism-regulating neurotransmitters, and enhanced glucose tolerance and utilization in the three species, whereas physical transection or chemical blocking of the liver-brain nerve pathway abolished the effect of pFUS on glucose tolerance. Longitudinal multi-omic profiling of metabolic tissues from the treated animals confirmed pFUS-induced modifications of key metabolic functions in liver, pancreas, muscle, adipose, kidney and intestinal tissues. Non-invasive ultrasound activation of afferent autonomic nerves may represent a non-pharmacologic therapy for the restoration of glucose homoeostasis in type-2 diabetes and other metabolic diseases.
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Affiliation(s)
- Victoria Cotero
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - John Graf
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Hiromi Miwa
- University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Khaled Qanud
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Tomás S Huerta
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Yuyan Ding
- Yale School of Medicine, New Haven, CT, USA
| | - Kevin Jimenez-Cowell
- Yale School of Medicine, New Haven, CT, USA
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Weiguo Song
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Alex Devarajan
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Tea Tsaava
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Radhika Madhavan
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Kirk Wallace
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Evelina Loghin
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Christine Morton
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Ying Fan
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Tzu-Jen Kao
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | | | | | | | | | - Jeffrey Ashe
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA
| | - Kevin J Tracey
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | - Dino Di Carlo
- University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Stavros Zanos
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | | | | | - Chris Puleo
- General Electric (GE) Research, 1 Research Circle, Niskayuna, NY, USA.
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13
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Picard A, Berney X, Castillo-Armengol J, Tarussio D, Jan M, Sanchez-Archidona AR, Croizier S, Thorens B. Hypothalamic Irak4 is a genetically-controlled regulator of hypoglycemia-induced glucagon secretion. Mol Metab 2022; 61:101479. [PMID: 35339728 PMCID: PMC9046887 DOI: 10.1016/j.molmet.2022.101479] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES Glucagon secretion to stimulate hepatic glucose production is a first line of defense against hypoglycemia. This response is triggered by so far incompletely characterized central hypoglycemia sensing mechanisms, which control autonomous nervous activity and hormone secretion. The objective of this study was to identify novel hypothalamic genes controlling insulin-induced glucagon secretion. METHODS To obtain new information about the mechanisms of hypothalamic hypoglycemia sensing, we combined genetic and transcriptomic analysis of the glucagon response to insulin-induced hypoglycemia in a panel of BXD recombinant inbred mice. RESULTS We identified two QTLs, on chromosome 8 and chromosome 15. We further investigated the role of Irak4 and Cpne8, both located in the chromosome 15 QTL, in C57BL/6J and DBA/2J mice, the BXD mouse parental strains. We found that the poor glucagon response of DBA/2J mice was associated with higher hypothalamic expression of Irak4, which encodes a kinase acting downstream of the interleukin-1 receptor (Il-1R), and of Il-ß when compared to C57BL/6J mice. We showed that intracerebroventricular administration of an Il-1R antagonist in DBA/2J restored insulin-induced glucagon secretion; this was associated with increased c-fos expression in the arcuate and paraventricular nuclei of the hypothalamus and with higher activation of both branches of the autonomous nervous system. Whole body inactivation of Cpne8, which encodes a Ca++-dependent regulator of membrane trafficking and exocytosis had, however, no impact on insulin-induced glucagon secretion. CONCLUSIONS Collectively, our data identify Irak4 as a genetically controlled regulator of hypoglycemia-activated hypothalamic neurons and glucagon secretion.
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Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Judit Castillo-Armengol
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Novo Nordisk A/S, Måløv, Denmark
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | | | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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14
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Mehan S, Bhalla S, Siddiqui EM, Sharma N, Shandilya A, Khan A. Potential Roles of Glucagon-Like Peptide-1 and Its Analogues in Dementia Targeting Impaired Insulin Secretion and Neurodegeneration. Degener Neurol Neuromuscul Dis 2022; 12:31-59. [PMID: 35300067 PMCID: PMC8921673 DOI: 10.2147/dnnd.s247153] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/16/2022] [Indexed: 12/20/2022] Open
Abstract
Dementia is a chronic, irreversible condition marked by memory loss, cognitive decline, and mental instability. It is clinically related to various progressive neurological diseases, including Parkinson’s disease, Alzheimer’s disease, and Huntington’s. The primary cause of neurological disorders is insulin desensitization, demyelination, oxidative stress, and neuroinflammation accompanied by various aberrant proteins such as amyloid-β deposits, Lewy bodies accumulation, tau formation leading to neurofibrillary tangles. Impaired insulin signaling is directly associated with amyloid-β and α-synuclein deposition, as well as specific signaling cascades involved in neurodegenerative diseases. Insulin dysfunction may initiate various intracellular signaling cascades, including phosphoinositide 3-kinase (PI3K), c-Jun N-terminal kinases (JNK), and mitogen-activated protein kinase (MAPK). Neuronal death, inflammation, neuronal excitation, mitochondrial malfunction, and protein deposition are all influenced by insulin. Recent research has focused on GLP-1 receptor agonists as a potential therapeutic target. They increase glucose-dependent insulin secretion and are beneficial in neurodegenerative diseases by reducing oxidative stress and cytokine production. They reduce the deposition of abnormal proteins by crossing the blood-brain barrier. The purpose of this article is to discuss the role of insulin dysfunction in the pathogenesis of neurological diseases, specifically dementia. Additionally, we reviewed the therapeutic target (GLP-1) and its receptor activators as a possible treatment of dementia.
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Affiliation(s)
- Sidharth Mehan
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
- Correspondence: Sidharth Mehan, Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, 142001, Punjab, India, Tel +91 8059889909; +91 9461322911, Email ;
| | - Sonalika Bhalla
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Ehraz Mehmood Siddiqui
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Nidhi Sharma
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Ambika Shandilya
- Neuropharmacology Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Andleeb Khan
- Department of Pharmacology & Toxicology, College of Pharmacy, Jazan University, Jazan, Kingdom of Saudi Arabia
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15
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Choi JH, Kim MS. Homeostatic Regulation of Glucose Metabolism by the Central Nervous System. Endocrinol Metab (Seoul) 2022; 37:9-25. [PMID: 35255598 PMCID: PMC8901968 DOI: 10.3803/enm.2021.1364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/07/2022] [Indexed: 12/04/2022] Open
Abstract
Evidence for involvement of the central nervous system (CNS) in the regulation of glucose metabolism dates back to the 19th century, although the majority of the research on glucose metabolism has focused on the peripheral metabolic organs. Due to recent advances in neuroscience, it has now become clear that the CNS is indeed vital for maintaining glucose homeostasis. To achieve normoglycemia, specific populations of neurons and glia in the hypothalamus sense changes in the blood concentrations of glucose and of glucoregulatory hormones such as insulin, leptin, glucagon-like peptide 1, and glucagon. This information is integrated and transmitted to other areas of the brain where it eventually modulates various processes in glucose metabolism (i.e., hepatic glucose production, glucose uptake in the brown adipose tissue and skeletal muscle, pancreatic insulin and glucagon secretion, renal glucose reabsorption, etc.). Errors in these processes lead to hyper- or hypoglycemia. We here review the current understanding of the brain regulation of glucose metabolism.
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Affiliation(s)
- Jong Han Choi
- Division of Endocrinology and Metabolism, Konkuk University Medical Center, Seoul,
Korea
| | - Min-Seon Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
- Appeptite Regulation Laboratory, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul,
Korea
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16
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Thorens B. Neuronal regulation of glucagon secretion and gluconeogenesis. J Diabetes Investig 2022; 13:599-607. [PMID: 34989155 PMCID: PMC9017634 DOI: 10.1111/jdi.13745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/02/2022] [Indexed: 11/29/2022] Open
Abstract
Hypoglycemia almost never develops in healthy individuals because multiple hypoglycemia sensing systems, located in the periphery and in the central nervous system trigger a coordinated counterregulatory hormonal response to restore normoglycemia. This involves not only the secretion of glucagon but also of epinephrine, norepinephrine, cortisol and growth hormone. Increased hepatic glucose production is also stimulated by direct autonomous nervous connections to the liver that stimulate glycogenolysis and gluconeogenesis. This counterregulatory response, however, becomes deregulated in a significant fraction of diabetic patients that receive insulin therapy. This leads to risk of developing hypoglycemic episodes, of increasing severity, which negatively impact the quality of life of the patients. How hypoglycemia is detected by the central nervous system is being actively investigated. Recent studies using novel molecular biological, optogenetic and chemogenetic techniques, allow the characterization of glucose sensing neurons, the mechanisms of hypoglycemia detection, the neuronal circuits in which they are integrated and the physiological responses they control. This review will discuss recent studies aimed at identifying central hypoglycemia sensing neuronal circuits, how neurons are activated by hypoglycemia, and how they restore normoglycemia.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
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17
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Rijal S, Jang SH, Cho DH, Han SK. Hydrogen peroxide suppresses excitability of gonadotropin-releasing hormone neurons in adult mouse. Front Endocrinol (Lausanne) 2022; 13:939699. [PMID: 36387844 PMCID: PMC9650413 DOI: 10.3389/fendo.2022.939699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/14/2022] [Indexed: 11/13/2022] Open
Abstract
It has been reported that reactive oxygen species (ROS) derived from oxygen molecule reduction can interfere with the cross-talk between the hypothalamic-pituitary-gonadal (HPG) axis and other endocrine axes, thus affecting fertility. Furthermore, ROS have been linked to GnRH receptor signaling in gonadotropes involved in gonadotropin release. There has been evidence that ROS can interfere with the HPG axis and gonadotropin release at various levels. However, the direct effect of ROS on gonadotropin-releasing hormone (GnRH) neuron remains unclear. Thus, the objective of this study was to determine the effect of hydrogen peroxide (H2O2), an ROS source, on GnRH neuronal excitabilities in transgenic GnRH-green fluorescent protein-tagged mice using the whole-cell patch-clamp electrophysiology. In adults, H2O2 at high concentrations (mM level) hyperpolarized most GnRH neurons tested, whereas low concentrations (pM to μM) caused slight depolarization. In immature GnRH neurons, H2O2 exposure induced excitation. The sensitivity of GnRH neurons to H2O2 was increased with postnatal development. The effect of H2O2 on adult female GnRH neurons was found to be estrous cycle-dependent. Hyperpolarization mediated by H2O2 persisted in the presence of tetrodotoxin, a voltage-gated Na+ channel blocker, and amino-acids receptor blocking cocktail containing blockers for the ionotropic glutamate receptors, glycine receptors, and GABAA receptors, indicating that H2O2 could act on GnRH neurons directly. Furthermore, glibenclamide, an ATP-sensitive K+ (KATP) channel blocker, completely blocked H2O2-mediated hyperpolarization. Increasing endogenous H2O2 by inhibiting glutathione peroxidase decreased spontaneous activities of most GnRH neurons. We conclude that ROS can act as signaling molecules for regulating GnRH neuron's excitability and that adult GnRH neurons are sensitive to increased ROS concentration. Results of this study demonstrate that ROS have direct modulatory effects on the HPG axis at the hypothalamic level to regulate GnRH neuron's excitabilities.
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Affiliation(s)
- Santosh Rijal
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Jeonbuk National University, Jeonju, South Korea
| | - Seon Hui Jang
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Jeonbuk National University, Jeonju, South Korea
| | - Dong Hyu Cho
- Department of Obstetrics and Gynecology, Jeonbuk National University Medical School, Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute for Medical Sciences, Jeonbuk National University Hospital, Jeonju, South Korea
- *Correspondence: Dong Hyu Cho, ; Seong Kyu Han,
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Jeonbuk National University, Jeonju, South Korea
- *Correspondence: Dong Hyu Cho, ; Seong Kyu Han,
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18
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Jang JH, Kim HK, Seo DW, Ki SY, Park S, Choi SH, Kim DH, Moon SJ, Jeong YT. Whole-Brain Mapping of the Expression Pattern of T1R2, a Subunit Specific to the Sweet Taste Receptor. Front Neuroanat 2021; 15:751839. [PMID: 34776881 PMCID: PMC8581048 DOI: 10.3389/fnana.2021.751839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/04/2021] [Indexed: 12/29/2022] Open
Abstract
Chemosensory receptors are expressed primarily in sensory organs, but their expression elsewhere can permit ligand detection in other contexts that contribute to survival. The ability of sweet taste receptors to detect natural sugars, sugar alcohols, and artificial sweeteners suggests sweet taste receptors are involved in metabolic regulation in both peripheral organs and in the central nervous system. Our limited knowledge of sweet taste receptor expression in the brain, however, has made it difficult to assess their contribution to metabolic regulation. We, therefore, decided to profile the expression pattern of T1R2, a subunit specific to the sweet taste receptor complex, at the whole-brain level. Using T1r2-Cre knock-in mice, we visualized the overall distribution of Cre-labeled cells in the brain. T1r2-Cre is expressed not only in various populations of neurons, but also in glial populations in the circumventricular organs and in vascular structures in the cortex, thalamus, and striatum. Using immunohistochemistry, we found that T1r2 is expressed in hypothalamic neurons expressing neuropeptide Y and proopiomelanocortin in arcuate nucleus. It is also co-expressed with a canonical taste signaling molecule in perivascular cells of the median eminence. Our findings indicate that sweet taste receptors have unidentified functions in the brain and suggest that they may be a novel therapeutic target in the central nervous system.
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Affiliation(s)
- Jea Hwa Jang
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.,Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Ha Kyeong Kim
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.,Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Dong Woo Seo
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.,Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Su Young Ki
- Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Soonhong Park
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Sang-Hyun Choi
- Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Dong-Hoon Kim
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.,Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
| | - Seok Jun Moon
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Yong Taek Jeong
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul, South Korea.,Department of Pharmacology, Korea University College of Medicine, Seoul, South Korea
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19
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Karagiannis A, Gallopin T, Lacroix A, Plaisier F, Piquet J, Geoffroy H, Hepp R, Naudé J, Le Gac B, Egger R, Lambolez B, Li D, Rossier J, Staiger JF, Imamura H, Seino S, Roeper J, Cauli B. Lactate is an energy substrate for rodent cortical neurons and enhances their firing activity. eLife 2021; 10:e71424. [PMID: 34766906 PMCID: PMC8651295 DOI: 10.7554/elife.71424] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Glucose is the mandatory fuel for the brain, yet the relative contribution of glucose and lactate for neuronal energy metabolism is unclear. We found that increased lactate, but not glucose concentration, enhances the spiking activity of neurons of the cerebral cortex. Enhanced spiking was dependent on ATP-sensitive potassium (KATP) channels formed with KCNJ11 and ABCC8 subunits, which we show are functionally expressed in most neocortical neuronal types. We also demonstrate the ability of cortical neurons to take-up and metabolize lactate. We further reveal that ATP is produced by cortical neurons largely via oxidative phosphorylation and only modestly by glycolysis. Our data demonstrate that in active neurons, lactate is preferred to glucose as an energy substrate, and that lactate metabolism shapes neuronal activity in the neocortex through KATP channels. Our results highlight the importance of metabolic crosstalk between neurons and astrocytes for brain function.
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Affiliation(s)
- Anastassios Karagiannis
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Thierry Gallopin
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Alexandre Lacroix
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Fabrice Plaisier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Juliette Piquet
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Hélène Geoffroy
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Régine Hepp
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jérémie Naudé
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Benjamin Le Gac
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Richard Egger
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bertrand Lambolez
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Dongdong Li
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jean Rossier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Göttingen, Georg-August- University GöttingenGoettingenGermany
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of MedicineHyogoJapan
| | - Jochen Roeper
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bruno Cauli
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
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Abstract
K+ channels enable potassium to flow across the membrane with great selectivity. There are four K+ channel families: voltage-gated K (Kv), calcium-activated (KCa), inwardly rectifying K (Kir), and two-pore domain potassium (K2P) channels. All four K+ channels are formed by subunits assembling into a classic tetrameric (4x1P = 4P for the Kv, KCa, and Kir channels) or tetramer-like (2x2P = 4P for the K2P channels) architecture. These subunits can either be the same (homomers) or different (heteromers), conferring great diversity to these channels. They share a highly conserved selectivity filter within the pore but show different gating mechanisms adapted for their function. K+ channels play essential roles in controlling neuronal excitability by shaping action potentials, influencing the resting membrane potential, and responding to diverse physicochemical stimuli, such as a voltage change (Kv), intracellular calcium oscillations (KCa), cellular mediators (Kir), or temperature (K2P).
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21
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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22
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Garcia SM, Hirschberg PR, Sarkar P, Siegel DM, Teegala SB, Vail GM, Routh VH. Insulin actions on hypothalamic glucose-sensing neurones. J Neuroendocrinol 2021; 33:e12937. [PMID: 33507001 PMCID: PMC10561189 DOI: 10.1111/jne.12937] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022]
Abstract
Subsequent to the discovery of insulin 100 years ago, great strides have been made in understanding its function, especially in the brain. It is now clear that insulin is a critical regulator of the neuronal circuitry controlling energy balance and glucose homeostasis. This review focuses on the effects of insulin and diabetes on the activity and glucose sensitivity of hypothalamic glucose-sensing neurones. We highlight the role of electrophysiological data in understanding how insulin regulates glucose-sensing neurones. A brief introduction describing the benefits and limitations of the major electrophysiological techniques used to investigate glucose-sensing neurones is provided. The mechanisms by which hypothalamic neurones sense glucose are discussed with an emphasis on those glucose-sensing neurones already shown to be modulated by insulin. Next, the literature pertaining to how insulin alters the activity and glucose sensitivity of these hypothalamic glucose-sensing neurones is described. In addition, the effects of impaired insulin signalling during diabetes and the ramifications of insulin-induced hypoglycaemia on hypothalamic glucose-sensing neurones are covered. To the extent that it is known, we present hypotheses concerning the mechanisms underlying the effects of these insulin-related pathologies. To conclude, electrophysiological data from the hippocampus are evaluated aiming to provide clues regarding how insulin might influence neuronal plasticity in glucose-sensing neurones. Although much has been accomplished subsequent to the discovery of insulin, the work described in our review suggests that the regulation of central glucose sensing by this hormone is both important and understudied.
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Affiliation(s)
- Stephanie M Garcia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pamela R Hirschberg
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pallabi Sarkar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Dashiel M Siegel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Suraj B Teegala
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Gwyndolin M Vail
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Vanessa H Routh
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
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23
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Senik MH, Abu IF, Fadhullah W. Analysis of K ATP Channels Opening Probability of Hippocampus Cells Treated with Kainic Acid. Malays J Med Sci 2021; 28:15-26. [PMID: 33679216 PMCID: PMC7909348 DOI: 10.21315/mjms2021.28.1.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/12/2020] [Indexed: 01/14/2023] Open
Abstract
Background Kainic acid (KA)-induced seizures may be a valuable tool in the assessment of anti-epileptic drug efficacy in complex partial seizures. This study investigated the effects of KA on ATP-sensitive K+ (KATP) channels opening probability (NPo), which plays a crucial role in neuronal activities. Methods For the optimisation and validation protocol, β-cells were plated onto 35 mm plastic petri dishes and maintained in RPMI-1640 media supplemented with 10 mM glucose, 10% FCS and 25 mM of N-2-hydroxyethylpiperazine-N-ethanesulfonic acid (HEPES). The treatment effects of 10 mM glucose and 30 μM fluoxetine on KATP channels NPo of β-cells were assessed via cell-attached patch-clamp recordings. For hippocampus cell experiments, hippocampi were harvested from day 17 of maternal Lister-hooded rat foetus, and then transferred to a Ca2+ and Mg2+-free HEPES-buffered Hank's salt solution (HHSS). The dissociated cells were cultured and plated onto a 25 mm round cover glasses coated with poly-d-lysine (0.1 mg/mL) in a petri dish. The KATP channels NPo of hippocampus cells when perfused with 1 mM and 10 mM of KA were determined. Results NPo of β-cells showed significant decreasing patterns (P < 0.001) when treated with 10 mM glucose 0.048 (0.027) as well as 30 μM fluoxetine 0.190 (0.141) as compared to basal counterpart. In hippocampus cell experiment, a significant increase (P < 0.001) in mean NPo 2.148 (0.175) of neurons when applied with 1 mM of KA as compared to basal was observed. Conclusion The two concentrations of KA used in the study exerted contrasting effects toward the mean of NPo. It is hypothesised that KA at lower concentration (1 mM) opens more KATP channels, leading to hyperpolarisation of the neurons, which may prevent neuronal hyper excitability. No effect was shown in 10 mM KA treatment, suggesting that only lower than 10 mM KA produced significant changes in KATP channels. This implies further validation of KA concentration to be used in the future.
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Affiliation(s)
- Mohd Harizal Senik
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.,School of Life Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Izuddin Fahmy Abu
- Institute of Medical Science Technology, Universiti Kuala Lumpur, Kuala Lumpur, Malaysia
| | - Widad Fadhullah
- School of Industrial Technology, Universiti Sains Malaysia, Pulau Pinang, Malaysia
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24
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Yildirim C, Özkaya B, Bal R. KATP and TRPM2-like channels couple metabolic status to resting membrane potential of octopus neurons in the mouse ventral cochlear nucleus. Brain Res Bull 2021; 170:115-128. [PMID: 33581312 DOI: 10.1016/j.brainresbull.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/29/2022]
Abstract
ATP-sensitive potassium (KATP) channels and transient receptor potential melastatin 2 (TRPM2) channels are commonly expressed both pre- and postsynaptically in the central nervous system (CNS). We hypothesized that KATP and TRPM2 may couple metabolic status to the resting membrane potential of octopus neurons of the mouse ventral cochlear nucleus (VCN). Therefore, we studied the expression of KATP channels and TRPM2 channels in octopus cells by immunohistochemical techniques and their contribution to neuronal electrical properties by the electrophysiological patch clamp technique. In immunohistochemical staining of octopus cells, labelling with Kir6.2 and SUR1 antibodies was strong, and labelling with the SUR2 antibody was moderate, but labelling with Kir6.1 was very weak. Octopus cells had intense staining with TRPM2 antibodies. In patch clamp recordings, bath application of KATP channel agonists H2O2 (880 μM), ATZ (1 mM), cromakalim (50 μM), diazoxide (200 μM), NNC 55-0118 and NN 414 separately resulted in hyperpolarizations of resting potential to different extents. Application of 8-Bro-cADPR (50 μM), a specific antagonist of TRPM2 channels, in the presence of H2O2 (880 μM) resulted in further hyperpolarization by approximately 1 mV. The amplitudes of H2O2-induced outward KATP currents and ADPR-induced inward currents were 206.1 ± 31.5 pA (n = 4) and 136.8 ± 22.4 pA, respectively, at rest. Their respective reversal potentials were -77 ± 2.6 mV (n = 3) and -6.3 ± 2.9 (n = 3) and -6.3 ± 2.9 (n = 3). In conclusion, octopus cells appear to possess both KATP channels and TRPM2-like channels. KATP might largely be constituted by SUR1-Kir6.2 subunits and SUR2-Kir6.2 subunits. Both KATP and TRPM2-like channels might have a modulatory action in setting the membrane potential.
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Affiliation(s)
- Caner Yildirim
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Beytullah Özkaya
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey.
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25
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Sprengell M, Kubera B, Peters A. Brain More Resistant to Energy Restriction Than Body: A Systematic Review. Front Neurosci 2021; 15:639617. [PMID: 33633541 PMCID: PMC7900631 DOI: 10.3389/fnins.2021.639617] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/07/2021] [Indexed: 01/10/2023] Open
Abstract
The gluco-lipostatic theory and its modern variants assume that blood glucose and energy stores are controlled in closed-loop feedback processes. The Selfish Brain theory is based on the same assumptions, but additionally postulates that the brain, as an independent energy compartment, self-regulates its energy concentration with the highest priority. In some clinical situations these two theories make opposite predictions. To investigate one of these situations, namely caloric restriction, we formulated a hypothesis which, if confirmed, would match the predictions of the Selfish Brain theory—but not those of the gluco-lipostatic theory. Hypothesis: Calorie restriction causes minor mass (energy) changes in the brain as opposed to major changes in the body. We conducted a systematic review of caloric-restriction studies to test whether or not the evaluated studies confirmed this hypothesis. We identified 3,157 records, screened 2,804 works by title or abstract, and analyzed 232 by full text. According to strict selection criteria (set out in our PROSPERO preregistration, complying with PRISMA guidelines, and the pre-defined hypothesis-decision algorithm), 8 papers provided enough information to decide on the hypothesis: In animals, high-energy phosphates were measured by 31P-nuclear magnetic resonance, and organ and total body weights were measured by scales, while in humans organ sizes were determined by magnetic resonance imaging. All 8 decidable papers confirmed the hypothesis, none spoke against it. The evidence presented here clearly shows that the most accurate predictions are possible with a theory that regards the brain as independently self-regulating and as occupying a primary position in a hierarchically organized energy metabolism.
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Affiliation(s)
- Marie Sprengell
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Britta Kubera
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| | - Achim Peters
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
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26
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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27
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Haigh JL, New LE, Filippi BM. Mitochondrial Dynamics in the Brain Are Associated With Feeding, Glucose Homeostasis, and Whole-Body Metabolism. Front Endocrinol (Lausanne) 2020; 11:580879. [PMID: 33240218 PMCID: PMC7680879 DOI: 10.3389/fendo.2020.580879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
The brain is responsible for maintaining whole-body energy homeostasis by changing energy input and availability. The hypothalamus and dorsal vagal complex (DVC) are the primary sites of metabolic control, able to sense both hormones and nutrients and adapt metabolism accordingly. The mitochondria respond to the level of nutrient availability by fusion or fission to maintain energy homeostasis; however, these processes can be disrupted by metabolic diseases including obesity and type II diabetes (T2D). Mitochondrial dynamics are crucial in the development and maintenance of obesity and T2D, playing a role in the control of glucose homeostasis and whole-body metabolism across neurons and glia in the hypothalamus and DVC.
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Affiliation(s)
| | | | - Beatrice M. Filippi
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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28
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Zhao G, Kaplan A, Greiser M, Lederer WJ. The surprising complexity of KATP channel biology and of genetic diseases. J Clin Invest 2020; 130:1112-1115. [PMID: 32065592 DOI: 10.1172/jci135759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The ATP-sensitive K+ channel (KATP) is formed by the association of four inwardly rectifying K+ channel (Kir6.x) pore subunits with four sulphonylurea receptor (SUR) regulatory subunits. Kir6.x or SUR mutations result in KATP channelopathies, which reflect the physiological roles of these channels, including but not limited to insulin secretion, cardiac protection, and blood flow regulation. In this issue of the JCI, McClenaghan et al. explored one of the channelopathies, namely Cantu syndrome (CS), which is a result of one kind of KATP channel mutation. Using a knockin mouse model, the authors demonstrated that gain-of-function KATP mutations in vascular smooth muscle resulted in cardiac remodeling. Moreover, they were able to reverse the cardiovascular phenotypes by administering the KATP channel blocker glibenclamide. These results exemplify how genetic mutations can have an impact on developmental trajectories, and provide a therapeutic approach to mitigate cardiac hypertrophy in cases of CS.
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Affiliation(s)
- Guiling Zhao
- Center for Biomedical Engineering and Technology and Department of Physiology
| | - Aaron Kaplan
- Center for Biomedical Engineering and Technology and Department of Physiology.,Department of Medicine and Division of Cardiology, University of Maryland Baltimore, School of Medicine, Baltimore, Maryland, USA
| | - Maura Greiser
- Center for Biomedical Engineering and Technology and Department of Physiology
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology and Department of Physiology
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29
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Sohn JW, Ho WK. Cellular and systemic mechanisms for glucose sensing and homeostasis. Pflugers Arch 2020; 472:1547-1561. [PMID: 32960363 DOI: 10.1007/s00424-020-02466-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/14/2020] [Accepted: 09/14/2020] [Indexed: 12/25/2022]
Abstract
Glucose is a major source of energy in animals. Maintaining blood glucose levels within a physiological range is important for facilitating glucose uptake by cells, as required for optimal functioning. Glucose homeostasis relies on multiple glucose-sensing cells in the body that constantly monitor blood glucose levels and respond accordingly to adjust its glycemia. These include not only pancreatic β-cells and α-cells that secrete insulin and glucagon, but also central and peripheral neurons regulating pancreatic endocrine function. Different types of cells respond distinctively to changes in blood glucose levels, and the mechanisms involved in glucose sensing are diverse. Notably, recent studies have challenged the currently held views regarding glucose-sensing mechanisms. Furthermore, peripheral and central glucose-sensing cells appear to work in concert to control blood glucose level and maintain glucose and energy homeostasis in organisms. In this review, we summarize the established concepts and recent advances in the understanding of cellular and systemic mechanisms that regulate glucose sensing and its homeostasis.
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Affiliation(s)
- Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, South Korea.
| | - Won-Kyung Ho
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongro-gu, Seoul, 03080, South Korea.
- Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea.
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30
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Glucose transporters in brain in health and disease. Pflugers Arch 2020; 472:1299-1343. [PMID: 32789766 PMCID: PMC7462931 DOI: 10.1007/s00424-020-02441-x] [Citation(s) in RCA: 219] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
Energy demand of neurons in brain that is covered by glucose supply from the blood is ensured by glucose transporters in capillaries and brain cells. In brain, the facilitative diffusion glucose transporters GLUT1-6 and GLUT8, and the Na+-d-glucose cotransporters SGLT1 are expressed. The glucose transporters mediate uptake of d-glucose across the blood-brain barrier and delivery of d-glucose to astrocytes and neurons. They are critically involved in regulatory adaptations to varying energy demands in response to differing neuronal activities and glucose supply. In this review, a comprehensive overview about verified and proposed roles of cerebral glucose transporters during health and diseases is presented. Our current knowledge is mainly based on experiments performed in rodents. First, the functional properties of human glucose transporters expressed in brain and their cerebral locations are described. Thereafter, proposed physiological functions of GLUT1, GLUT2, GLUT3, GLUT4, and SGLT1 for energy supply to neurons, glucose sensing, central regulation of glucohomeostasis, and feeding behavior are compiled, and their roles in learning and memory formation are discussed. In addition, diseases are described in which functional changes of cerebral glucose transporters are relevant. These are GLUT1 deficiency syndrome (GLUT1-SD), diabetes mellitus, Alzheimer’s disease (AD), stroke, and traumatic brain injury (TBI). GLUT1-SD is caused by defect mutations in GLUT1. Diabetes and AD are associated with changed expression of glucose transporters in brain, and transporter-related energy deficiency of neurons may contribute to pathogenesis of AD. Stroke and TBI are associated with changes of glucose transporter expression that influence clinical outcome.
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31
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Kuo YY, Lin JK, Lin YT, Chen JC, Kuo YM, Chen PS, Wu SN, Chen PC. Glibenclamide restores dopaminergic reward circuitry in obese mice through interscauplar brown adipose tissue. Psychoneuroendocrinology 2020; 118:104712. [PMID: 32479969 DOI: 10.1016/j.psyneuen.2020.104712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Obesity, a critical feature in metabolic disorders, is associated with medical depression. Recent evidence reveals that brown adipose tissue (BAT) activity may contribute to mood disorders, Adenosine triphosphate (ATP)-sensitive K+ (KATP) channels regulate BAT sympathetic nerve activity. However, the mechanism through which BAT activity affects mood control remains unknown. We hypothesized the BAT is involved in depressive-like symptoms regulation by trafficking KATP channels. METHODS Eight-week-old male B6 mice fed with a high-fat diet (HFD) for 12 weeks exhibited characteristics of metabolic disorders, including hyperglycemia, hyperinsulinemia, and hyperlipidemia, as well as depressive symptoms. In this study, we surgically removed interscapular BAT in mice, and these mice exhibited immobility in the forced swim test and less preference for sugar water compared with other mice. To delineate the role of KATP channels in BAT activity regulation, we implanted a miniosmotic pump containing glibenclamide (GB), a KATP channel blocker, into the interscapular BAT of HFD-fed mice. RESULTS GB infusion improved glucose homeostasis, insulin sensitivity, and depressive-like symptoms. KATP channel expression was lower in HFD-fed mice than in chow-fed mice. Notably, GB infusion in HFD-fed mice restored KATP channel expression. CONCLUSION KATP channels are functionally expressed in BAT, and inhibiting BAT-KATP channels improves metabolic syndromes and reduces depressive symptoms through beta-3-adrenergic receptor-mediated protein kinase A signaling.
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Affiliation(s)
- Yi-Ying Kuo
- Department of Physiology, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | | | - Ya-Tin Lin
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Jin-Chung Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Yu-Ming Kuo
- Department of Cell Biology and Anatomy, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Po-See Chen
- Department of Psychiatry, National Cheng Kung University Hospital, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Pei-Chun Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan.
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Cotero V, Miwa H, Graf J, Ashe J, Loghin E, Di Carlo D, Puleo C. Peripheral Focused Ultrasound Neuromodulation (pFUS). J Neurosci Methods 2020; 341:108721. [DOI: 10.1016/j.jneumeth.2020.108721] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 03/03/2020] [Accepted: 04/01/2020] [Indexed: 01/28/2023]
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Lei H, Gruetter R. Metabolic and perfusion responses to acute hypoglycemia in the rat cortex: A non-invasive magnetic resonance approach. J Neurochem 2020; 154:71-83. [PMID: 32306383 DOI: 10.1111/jnc.15028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 11/30/2022]
Abstract
Hypoglycemia is critical condition during diabetic treatment that involves intensive insulin therapy, and it may impair brain function. We aimed to compare cortical responses of three hypoglycemic phases and the restoration of glycemia to control levels after a severe episode in rats using non-invasive perfusion magnetic resonance (MR) imaging and localized 1 H MR spectroscopy. Under light α-chloralose anesthesia, cortical blood flow (cCBF) was 42 ± 3 ml/100 g/min at euglycemia (~ 5 mM plasma glucose), was not altered at mild hypoglycemia I (42 ± 4 ml/100 g/min, 2-3.5 mM), increased to 60 ± 8 ml/100 g/min under moderate hypoglycemia II (1-2 mM) and amplified to 190 ± 35 ml/100 g/min at severe hypoglycemia III (< 1 mM). 1 H MRS revealed metabolic changes at hypoglycemia I without any perfusion alteration. At hypoglycemia III, glutamine and glutamate decreased, whereas aspartate increased. When animals subsequently regained glycemic control, not all metabolites returned to their control levels, for example, glutamine. Meanwhile, ascorbate was increased with amplified hypoglycemic severity, whereas glutathione was reduced; these compounds did not return to normal levels upon the restoration of glycemia. Our study is the first to report cCBF and neurochemical changes in cortex upon five glycemic stages. The cortical responses of different hypoglycemic phases would explain variable neuronal damages after hypoglycemia and might help identify the degrees of hypoglycemic insults and further improve alternative therapies.
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Affiliation(s)
- Hongxia Lei
- Animal Imaging Technology (AIT), Center for Biomedical Imaging Research (CIBM), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Rolf Gruetter
- Animal Imaging Technology (AIT), Center for Biomedical Imaging Research (CIBM), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.,Wuhan United Imaging Life Science Instruments Ltd., Wuhan, P.R.China.,Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland.,Department of Radiology, University of Geneva, Geneva, Switzerland
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Yu Q, Lai BK, Ahooghalandari P, Helander A, Gylfe E, Gilon P, Tengholm A. γ-Hydroxybutyrate does not mediate glucose inhibition of glucagon secretion. J Biol Chem 2020; 295:5419-5426. [PMID: 32156704 PMCID: PMC7170508 DOI: 10.1074/jbc.ra119.009577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 03/09/2020] [Indexed: 11/26/2022] Open
Abstract
Hypersecretion of glucagon from pancreatic α-cells strongly contributes to diabetic hyperglycemia. Moreover, failure of α-cells to increase glucagon secretion in response to falling blood glucose concentrations compromises the defense against hypoglycemia, a common complication in diabetes therapy. However, the mechanisms underlying glucose regulation of glucagon secretion are poorly understood and likely involve both α-cell-intrinsic and intraislet paracrine signaling. Among paracrine factors, glucose-stimulated release of the GABA metabolite γ-hydroxybutyric acid (GHB) from pancreatic β-cells might mediate glucose suppression of glucagon release via GHB receptors on α-cells. However, the direct effects of GHB on α-cell signaling and glucagon release have not been investigated. Here, we found that GHB (4-10 μm) lacked effects on the cytoplasmic concentrations of the secretion-regulating messengers Ca2+ and cAMP in mouse α-cells. Glucagon secretion from perifused mouse islets was also unaffected by GHB at both 1 and 7 mm glucose. The GHB receptor agonist 3-chloropropanoic acid and the antagonist NCS-382 had no effects on glucagon secretion and did not affect stimulation of secretion induced by a drop in glucose from 7 to 1 mm Inhibition of endogenous GHB formation with the GABA transaminase inhibitor vigabatrin also failed to influence glucagon secretion at 1 mm glucose and did not prevent the suppressive effect of 7 mm glucose. In human islets, GHB tended to stimulate glucagon secretion at 1 mm glucose, an effect mimicked by 3-chloropropanoic acid. We conclude that GHB does not mediate the inhibitory effect of glucose on glucagon secretion.
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Affiliation(s)
- Qian Yu
- Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Bao Khanh Lai
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, 1200 Brussels, Belgium
| | | | - Anders Helander
- Department of Laboratory Medicine, Karolinska Institutet, and Clinical Pharmacology and Clinical Chemistry, Karolinska University Laboratory, SE-141 86 Stockholm, Sweden
| | - Erik Gylfe
- Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Patrick Gilon
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, 1200 Brussels, Belgium
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden.
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Walsh KB. Screening Technologies for Inward Rectifier Potassium Channels: Discovery of New Blockers and Activators. SLAS DISCOVERY 2020; 25:420-433. [PMID: 32292089 DOI: 10.1177/2472555220905558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
K+ channels play a critical role in maintaining the normal electrical activity of excitable cells by setting the cell resting membrane potential and by determining the shape and duration of the action potential. In nonexcitable cells, K+ channels establish electrochemical gradients necessary for maintaining salt and volume homeostasis of body fluids. Inward rectifier K+ (Kir) channels typically conduct larger inward currents than outward currents, resulting in an inwardly rectifying current versus voltage relationship. This property of inward rectification results from the voltage-dependent block of the channels by intracellular polyvalent cations and makes these channels uniquely designed for maintaining the resting potential near the K+ equilibrium potential (EK). The Kir family of channels consist of seven subfamilies of channels (Kir1.x through Kir7.x) that include the classic inward rectifier (Kir2.x) channel, the G-protein-gated inward rectifier K+ (GIRK) (Kir3.x), and the adenosine triphosphate (ATP)-sensitive (KATP) (Kir 6.x) channels as well as the renal Kir1.1 (ROMK), Kir4.1, and Kir7.1 channels. These channels not only function to regulate electrical/electrolyte transport activity, but also serve as effector molecules for G-protein-coupled receptors (GPCRs) and as molecular sensors for cell metabolism. Of significance, Kir channels represent promising pharmacological targets for treating a number of clinical conditions, including cardiac arrhythmias, anxiety, chronic pain, and hypertension. This review provides a brief background on the structure, function, and pharmacology of Kir channels and then focuses on describing and evaluating current high-throughput screening (HTS) technologies, such as membrane potential-sensitive fluorescent dye assays, ion flux measurements, and automated patch clamp systems used for Kir channel drug discovery.
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Affiliation(s)
- Kenneth B Walsh
- Department of Pharmacology, Physiology & Neuroscience, School of Medicine, University of South Carolina, Columbia, SC, USA
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36
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Puleo C, Cotero V. Noninvasive Neuromodulation of Peripheral Nerve Pathways Using Ultrasound and Its Current Therapeutic Implications. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a034215. [PMID: 31138539 DOI: 10.1101/cshperspect.a034215] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review describes work from several research groups in which ultrasound is being used to target the peripheral nervous system and perform neuromodulation noninvasively. Although these techniques are in their infancy compared to implant-based and electrical nerve stimulation, if successful this new noninvasive method for neuromodulation could solve many of the challenges facing the field of bioelectronic medicine. The work outlined herein shows results in which two different (potentially therapeutic) targets are stimulated, a neuroimmune pathway within the spleen and a nutrient/sensory pathway within the liver. Both data and discussion are provided that compare this new noninvasive technique to implant-based nerve stimulation.
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Melnick I, Krishtal OA, Colmers WF. Integration of energy homeostasis and stress by parvocellular neurons in rat hypothalamic paraventricular nucleus. J Physiol 2020; 598:1073-1092. [PMID: 31952096 DOI: 10.1113/jp279387] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/16/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Central regulation of energy homeostasis and stress are believed to be reciprocally regulated, i.e. excessive food intake suppresses, while prolonged hunger exacerbates, stress responses in vivo. This relationship may be mediated by neuroendocrine parvocellular corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus that receive both stress- and feeding-related input. We find that hunger strongly and selectively potentiates, while re-feeding suppresses, a cellular analogue of a stress response induced by acute glucopenia in CRH neurons in rat hypothalamic slices. Neuronal activation in response to glucopenia was mediated synaptically, via the relative enhancement of glutamate over GABA input. These results illustrate how acute stress responses may be initiated in vivo and show that it is reciprocally integrated with energy balance via local hypothalamic mechanisms acting at the level of CRH neurons and their afferent terminals. ABSTRACT Increased food intake is a common response to help cope with stress, implying the existence of a previously postulated but imperfectly understood, inverse relationship between the regulation of feeding and stress. We have identified components of the neural circuitry that can integrate these homeostatic responses. Prior fasting (∼24 h) potentiates, and re-feeding suppresses, excitatory responses to acute glucopenia in about half of the corticotropin releasing hormone (CRH)-expressing, putatively neurosecretory, stress-related neurons in the paraventricular nucleus of the hypothalamus studied. Glucoprivation stress ex vivo resulted from a preferential relative increase in excitatory (glutamatergic) over inhibitory (GABAergic) inputs. Putative preautonomic cells were less sensitive to fasting, and showed a predominant inhibition to acute glucopenia. We conclude that hunger may sensitize hypothalamic stress responses by acting via local mechanisms, at the level of CRH neurons and their presynaptic inputs. Those mechanisms involve neither presynaptic ATP-sensitive potassium channels nor postsynaptic ATP levels.
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Affiliation(s)
- Igor Melnick
- Bogomoletz Institute of Physiology, Bogomoletz str 4, Kiev, 01024, Ukraine
| | - Oleg A Krishtal
- Bogomoletz Institute of Physiology, Bogomoletz str 4, Kiev, 01024, Ukraine
| | - William F Colmers
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
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Gilon P. The Role of α-Cells in Islet Function and Glucose Homeostasis in Health and Type 2 Diabetes. J Mol Biol 2020; 432:1367-1394. [PMID: 31954131 DOI: 10.1016/j.jmb.2020.01.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 01/09/2023]
Abstract
Pancreatic α-cells are the major source of glucagon, a hormone that counteracts the hypoglycemic action of insulin and strongly contributes to the correction of acute hypoglycemia. The mechanisms by which glucose controls glucagon secretion are hotly debated, and it is still unclear to what extent this control results from a direct action of glucose on α-cells or is indirectly mediated by β- and/or δ-cells. Besides its hyperglycemic action, glucagon has many other effects, in particular on lipid and amino acid metabolism. Counterintuitively, glucagon seems also required for an optimal insulin secretion in response to glucose by acting on its cognate receptor and, even more importantly, on GLP-1 receptors. Patients with diabetes mellitus display two main alterations of glucagon secretion: a relative hyperglucagonemia that aggravates hyperglycemia, and an impaired glucagon response to hypoglycemia. Under metabolic stress states, such as diabetes, pancreatic α-cells also secrete GLP-1, a glucose-lowering hormone, whereas the gut can produce glucagon. The contribution of extrapancreatic glucagon to the abnormal glucose homeostasis is unclear. Here, I review the possible mechanisms of control of glucagon secretion and the role of α-cells on islet function in healthy state. I discuss the possible causes of the abnormal glucagonemia in diabetes, with particular emphasis on type 2 diabetes, and I briefly comment the current antidiabetic therapies affecting α-cells.
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Affiliation(s)
- Patrick Gilon
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), Brussels, B-1200, Belgium.
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39
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Hall M, Walicka M, Traczyk I. [Reactive hypoglycemia - an interdisciplinary approach of the disease of XXI Century]. WIADOMOSCI LEKARSKIE (WARSAW, POLAND : 1960) 2020. [PMID: 32248180 DOI: 10.36740/wlek202002134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Reactive hypoglycemia is characterized by low blood glucose level in non-diabetic patients. It manifests as a syndrome of adrenergic and neuroglycopenic symptoms in the postprandial period, and their resolution occurs after consuming carbohydrates. The etiology of reactive hypoglycemia is not fully understood. It may occur in patients after gastrointestinal surgery due to too fast gastric emptying. Decreases in postprandial glucose are also observed in people with a pre-diabetes condition in which insulin secretion is disturbed. Hypoglycaemia can also be seen in patients with insulin resistance and hyperinsulinism. The aim of this study was to summarize existing knowledge about reactive hypoglycemia - etiology, diagnostic model and treatment.
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Affiliation(s)
- Marianna Hall
- Zakład Żywienia Człowieka, Wydział Nauk o Zdrowiu, Warszawki Uniwersytet Medyczny, Warszawa, Polska, Klinika Chorób Wewnętrznych, Endokrynologii i Diabetologii CSK MSWiA w Warszawie, Warszawa, Polska
| | - Magdalena Walicka
- Klinika Chorób Wewnętrznych, Endokrynologii i Diabetologii CSK MSWiA w Warszawie, Warszawa, Polska
| | - Iwona Traczyk
- Zakład Żywienia Człowieka, Wydział Nauk o Zdrowiu, Warszawki Uniwersytet Medyczny, Warszawa, Polska
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40
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Bouagnon AD, Lin L, Srivastava S, Liu CC, Panda O, Schroeder FC, Srinivasan S, Ashrafi K. Intestinal peroxisomal fatty acid β-oxidation regulates neural serotonin signaling through a feedback mechanism. PLoS Biol 2019; 17:e3000242. [PMID: 31805041 PMCID: PMC6917301 DOI: 10.1371/journal.pbio.3000242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 12/17/2019] [Accepted: 11/15/2019] [Indexed: 02/02/2023] Open
Abstract
The ability to coordinate behavioral responses with metabolic status is fundamental to the maintenance of energy homeostasis. In numerous species including Caenorhabditis elegans and mammals, neural serotonin signaling regulates a range of food-related behaviors. However, the mechanisms that integrate metabolic information with serotonergic circuits are poorly characterized. Here, we identify metabolic, molecular, and cellular components of a circuit that links peripheral metabolic state to serotonin-regulated behaviors in C. elegans. We find that blocking the entry of fatty acyl coenzyme As (CoAs) into peroxisomal β-oxidation in the intestine blunts the effects of neural serotonin signaling on feeding and egg-laying behaviors. Comparative genomics and metabolomics revealed that interfering with intestinal peroxisomal β-oxidation results in a modest global transcriptional change but significant changes to the metabolome, including a large number of changes in ascaroside and phospholipid species, some of which affect feeding behavior. We also identify body cavity neurons and an ether-a-go-go (EAG)-related potassium channel that functions in these neurons as key cellular components of the circuitry linking peripheral metabolic signals to regulation of neural serotonin signaling. These data raise the possibility that the effects of serotonin on satiety may have their origins in feedback, homeostatic metabolic responses from the periphery.
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Affiliation(s)
- Aude D. Bouagnon
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Lin Lin
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Shubhi Srivastava
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Chung-Chih Liu
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Oishika Panda
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Frank C. Schroeder
- Boyce Thompson Institute, Cornell University, Ithaca, New York, United States of America
| | - Supriya Srinivasan
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, United States of America
| | - Kaveh Ashrafi
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
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Filion KB, Douros A, Azoulay L, Yin H, Yu OH, Suissa S. Sulfonylureas as initial treatment for type 2 diabetes and the risk of adverse cardiovascular events: A population-based cohort study. Br J Clin Pharmacol 2019; 85:2378-2389. [PMID: 31276600 PMCID: PMC6783602 DOI: 10.1111/bcp.14056] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 06/07/2019] [Accepted: 06/17/2019] [Indexed: 12/13/2022] Open
Abstract
AIMS Sulfonylureas are recommended as second-line treatment in the management of type 2 diabetes. However, they are still commonly used also as first-line treatment instead of metformin. Given the controversial cardiovascular safety of sulfonylureas, we aimed to determine if their use as first-line treatment is associated with adverse cardiovascular events among patients with newly treated type 2 diabetes compared with metformin. METHODS We conducted a population-based cohort study of patients with newly treated type 2 diabetes using the UK's Clinical Practice Research Datalink. Initiators of metformin and sulfonylurea monotherapy were matched on high-dimensional propensity score, and Cox proportional hazards models were used to compare the rate of cardiovascular events (myocardial infarction, ischaemic stroke, cardiovascular death, and all-cause mortality) with sulfonylureas vs metformin. RESULTS Our cohort included 94 750 patients initiating treatment for type 2 diabetes, 17 612 on a sulfonylurea and 77 138 on metformin. After matching, sulfonylurea monotherapy, compared with metformin monotherapy, was not associated with an increased risk of myocardial infarction (hazard ratio [HR]: 1.04, 95% confidence interval [CI]: 0.85-1.25) but was associated with increased risks of ischaemic stroke (HR: 1.25, 95% CI: 1.002-1.56), cardiovascular death (HR: 1.25, 95% CI: 1.06-1.47), and all-cause mortality (HR: 1.60, 95% CI: 1.45-1.76). This represents an additional 2.0 ischaemic strokes, 3.5 cardiovascular deaths, and 21.4 all-cause deaths per 1,000 patients per year with sulfonylureas. CONCLUSIONS Initiating treatment of type 2 diabetes with a sulfonylurea rather than metformin is associated with higher rates of ischaemic stroke, cardiovascular death, and all-cause mortality.
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Affiliation(s)
- Kristian B. Filion
- Department of MedicineMcGill UniversityMontrealQuebecCanada
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
- Department of Epidemiology, Biostatistics, and Occupational HealthMcGill UniversityMontrealQuebecCanada
| | - Antonios Douros
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
- Department of Epidemiology, Biostatistics, and Occupational HealthMcGill UniversityMontrealQuebecCanada
- Institute of Clinical Pharmacology and ToxicologyCharité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu BerlinBerlinGermany
- Berlin Institute of HealthBerlinGermany
| | - Laurent Azoulay
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
- Department of Epidemiology, Biostatistics, and Occupational HealthMcGill UniversityMontrealQuebecCanada
- Gerald Bronfman Department of OncologyMcGill UniversityMontrealQuebecCanada
| | - Hui Yin
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
| | - Oriana H. Yu
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
- Division of Endocrinology, Jewish General HospitalMcGill UniversityMontrealQuebecCanada
| | - Samy Suissa
- Department of MedicineMcGill UniversityMontrealQuebecCanada
- Center for Clinical EpidemiologyLady Davis Institute, Jewish General HospitalMontrealQuebecCanada
- Department of Epidemiology, Biostatistics, and Occupational HealthMcGill UniversityMontrealQuebecCanada
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Ren H, Vieira-de-Abreu A, Yan S, Reilly AM, Chan O, Accili D. Altered Central Nutrient Sensing in Male Mice Lacking Insulin Receptors in Glut4-Expressing Neurons. Endocrinology 2019; 160:2038-2048. [PMID: 31199472 PMCID: PMC6691683 DOI: 10.1210/en.2019-00341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/08/2019] [Indexed: 12/20/2022]
Abstract
Insulin signaling in the central nervous system influences satiety, counterregulation, and peripheral insulin sensitivity. Neurons expressing the Glut4 glucose transporter influence peripheral insulin sensitivity. Here, we analyzed the effects of insulin receptor (IR) signaling in hypothalamic Glut4 neurons on glucose sensing as well as leptin and amino acid signaling. By measuring electrophysiological responses to low glucose conditions, we found that the majority of Glut4 neurons in the ventromedial hypothalamus (VMH) were glucose excitatory neurons. GLUT4-Cre-driven insulin receptor knockout mice with a combined ablation of IR in Glut4-expressing tissues showed increased counterregulatory response to either 2-deoxyglucose-induced neuroglycopenia or systemic insulin-induced hypoglycemia. The latter response was recapitulated in mice with decreased VMH IR expression, suggesting that the effects on the counterregulatory response are likely mediated through the deletion of IRs on Glut4 neurons in the VMH. Using immunohistochemistry in fluorescently labeled hypothalamic Glut4 neurons, we showed that IR signaling promoted hypothalamic cellular signaling responses to the rise of insulin, leptin, and amino acids associated with feeding. We concluded that hypothalamic Glut4 neurons modulated the glucagon counterregulatory response and that IR signaling in Glut4 neurons was required to integrate hormonal and nutritional cues for the regulation of glucose metabolism.
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Affiliation(s)
- Hongxia Ren
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
- Correspondence: Hongxia Ren, PhD, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, Indiana 46202. E-mail: ; or Owen Chan, PhD, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, Utah 84112. E-mail:
| | - Adriana Vieira-de-Abreu
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah
| | - Shijun Yan
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Austin M Reilly
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Owen Chan
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, Utah
- Correspondence: Hongxia Ren, PhD, Indiana University School of Medicine, 635 Barnhill Drive, MS2031, Indianapolis, Indiana 46202. E-mail: ; or Owen Chan, PhD, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, University of Utah, 15 North 2030 East, EIHG Building 533, Room 2420B, Salt Lake City, Utah 84112. E-mail:
| | - Domenico Accili
- Department of Medicine and Berrie Diabetes Center, Columbia University College of Physicians & Surgeons, New York, New York
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43
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Yu Q, Shuai H, Ahooghalandari P, Gylfe E, Tengholm A. Glucose controls glucagon secretion by directly modulating cAMP in alpha cells. Diabetologia 2019; 62:1212-1224. [PMID: 30953108 PMCID: PMC6560012 DOI: 10.1007/s00125-019-4857-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/22/2019] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS Glucagon is critical for normal glucose homeostasis and aberrant secretion of the hormone aggravates dysregulated glucose control in diabetes. However, the mechanisms by which glucose controls glucagon secretion from pancreatic alpha cells remain elusive. The aim of this study was to investigate the role of the intracellular messenger cAMP in alpha-cell-intrinsic glucose regulation of glucagon release. METHODS Subplasmalemmal cAMP and Ca2+ concentrations were recorded in isolated and islet-located alpha cells using fluorescent reporters and total internal reflection microscopy. Glucagon secretion from mouse islets was measured using ELISA. RESULTS Glucose induced Ca2+-independent alterations of the subplasmalemmal cAMP concentration in alpha cells that correlated with changes in glucagon release. Glucose-lowering-induced stimulation of glucagon secretion thus corresponded to an elevation in cAMP that was independent of paracrine signalling from insulin or somatostatin. Imposed cAMP elevations stimulated glucagon secretion and abolished inhibition by glucose elevation, while protein kinase A inhibition mimicked glucose suppression of glucagon release. CONCLUSIONS/INTERPRETATION Glucose concentrations in the hypoglycaemic range control glucagon secretion by directly modulating the cAMP concentration in alpha cells independently of paracrine influences. These findings define a novel mechanism for glucose regulation of glucagon release that underlies recovery from hypoglycaemia and may be disturbed in diabetes.
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Affiliation(s)
- Qian Yu
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Hongyan Shuai
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Parvin Ahooghalandari
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Erik Gylfe
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden.
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Stanley S, Moheet A, Seaquist ER. Central Mechanisms of Glucose Sensing and Counterregulation in Defense of Hypoglycemia. Endocr Rev 2019; 40:768-788. [PMID: 30689785 PMCID: PMC6505456 DOI: 10.1210/er.2018-00226] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
Glucose homeostasis requires an organism to rapidly respond to changes in plasma glucose concentrations. Iatrogenic hypoglycemia as a result of treatment with insulin or sulfonylureas is the most common cause of hypoglycemia in humans and is generally only seen in patients with diabetes who take these medications. The first response to a fall in glucose is the detection of impending hypoglycemia by hypoglycemia-detecting sensors, including glucose-sensing neurons in the hypothalamus and other regions. This detection is then linked to a series of neural and hormonal responses that serve to prevent the fall in blood glucose and restore euglycemia. In this review, we discuss the current state of knowledge about central glucose sensing and how detection of a fall in glucose leads to the stimulation of counterregulatory hormone and behavior responses. We also review how diabetes and recurrent hypoglycemia impact glucose sensing and counterregulation, leading to development of impaired awareness of hypoglycemia in diabetes.
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Affiliation(s)
- Sarah Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Amir Moheet
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Elizabeth R Seaquist
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
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Zhancheng W, Wenhui J, Yun J, Lingli W, Huijun H, Yan S, Jin L. The dominant models of KCNJ11 E23K and KCNMB1 E65K are associated with essential hypertension (EH) in Asian: Evidence from a meta-analysis. Medicine (Baltimore) 2019; 98:e15828. [PMID: 31169684 PMCID: PMC6571424 DOI: 10.1097/md.0000000000015828] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The K channel, subfamily J, member-11 (KCNJ11) E23K and β1 subunit of large-conductance Ca-activated K channel (KCNMB1) E65K polymorphisms were shown to be associated with the risk of essential hypertension (EH). However, the results were inconclusive with relatively small sample size. Thus, we carried out a meta-analysis to investigate the genetic association between KCNJ11 E23K and KCNMB1 E65K polymorphisms and essential hypertension risk. METHODS Relative studies were collected using PubMed, Web of Science, the Cochrane Library databases, Chinese National Knowledge Infrastructure and Embase databases. Pooled odds ratios with 95% confidence intervals were used to assess the strength of associations. RESULTS The dominant models of KCNJ11 E23K (P = .006, OR [95%CI] = 0.45 [0.25, 0.79]) and KCNMB1 E65K (P = .04, OR [95%CI] = 0.91 [0.83, 1.00]) were significantly associated with essential hypertension risk. No significant association was detected between the allelic and recessive models of KCNJ11 E23K and KCNMB1 E65K and the susceptibility of EH. Subgroup analysis stratified by ethnicity showed that the dominant model of KCNMB1 E65K was associated with EH risk in Asian population (P = .003, OR [95%CI] = 0.83 [0.74, 0.94]), but not in Caucasian (P = .74, OR [95%CI] = 1.02 [0.89, 1.18]). CONCLUSIONS The dominant model of KCNJ11 E23K and KCNMB1 E65K might be susceptible factors for essential hypertension. To confirm this result, large-scale case-control studies with more subjects are necessary.
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Affiliation(s)
- Wang Zhancheng
- Department of Cardiology, Shanghai Eighth People's Hospital
| | - Ji Wenhui
- Department of Internal medicine, Huajing Community Health Service Centre for Xuhui District, Shanghai, China
| | - Jiang Yun
- Department of Cardiology, Shanghai Eighth People's Hospital
| | - Wang Lingli
- Department of Cardiology, Shanghai Eighth People's Hospital
| | - Huang Huijun
- Department of Cardiology, Shanghai Eighth People's Hospital
| | - Shen Yan
- Department of Cardiology, Shanghai Eighth People's Hospital
| | - Li Jin
- Department of Cardiology, Shanghai Eighth People's Hospital
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Nilsson IAK. The anx/anx Mouse - A Valuable Resource in Anorexia Nervosa Research. Front Neurosci 2019; 13:59. [PMID: 30804742 PMCID: PMC6370726 DOI: 10.3389/fnins.2019.00059] [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: 11/29/2018] [Accepted: 01/21/2019] [Indexed: 01/31/2023] Open
Abstract
Animal models are invaluable resources in research concerning the neurobiology of anorexia nervosa (AN), to a large extent since valid clinical samples are rare. None of the existing models can capture all aspects of AN but they are able to mirror the core features of the disorder e.g., elective starvation, emaciation and premature death. The anorectic anx/anx mouse is of particular value for the understanding of the abnormal response to negative energy balance seen in AN. These mice appear normal at birth but gradually develops starvation and emaciation despite full access to food, and die prematurely around three weeks of age. Several changes in hypothalamic neuropeptidergic and -transmitter systems involved in regulating food intake and metabolism have been documented in the anx/anx mouse. These changes are accompanied by signs of inflammation and degeneration in the same hypothalamic regions; including activation of microglia cells and expression of major histocompatibility complex I by microglia and selective neuronal populations. These aberrances are likely related to the dysfunction of complex I (CI) in the oxidative phosphorylation system of the mitochondria, and subsequent increased oxidative stress, which also has been revealed in the hypothalamus of these mice. Interestingly, a similar CI dysfunction has been shown in leukocytes from patients with AN. In addition, a higher expression of the Neurotrophic Receptor Tyrosine Kinase 3 gene has been shown in the anx/anx hypothalamus. This agrees with AN being associated with specific variants of the genes for brain derived neurotrophic factor and Neurotrophic Receptor Tyrosine Kinase 2. The anx/anx mouse is also glucose intolerant and display pancreatic dysfunction related to increased levels of circulating free fatty acids (FFA) and pancreatic inflammation. An increased incidence of eating disorders has been reported for young diabetic women, and as well has increased levels of circulating FFAs in AN. Also similar to individuals with AN, the anx/anx mouse has reduced leptin and increased cholesterol levels in serum. Thus, the anx/anx mouse shares several characteristics with patients with AN, including emaciation, starvation, premature death, diabetic features, increased FFA and low leptin, and is therefore a unique resource in research on the (neuro)biology of AN.
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Affiliation(s)
- Ida A K Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden.,Centre for Eating Disorders Innovation, Karolinska Institutet, Stockholm, Sweden
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47
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Bowman P, McDonald TJ, Knight BA, Flanagan SE, Leveridge M, Spaull SR, Shields BM, Hammersley S, Shepherd MH, Andrews RC, Patel KA, Hattersley AT. Patterns of postmeal insulin secretion in individuals with sulfonylurea-treated KCNJ11 neonatal diabetes show predominance of non-K ATP-channel pathways. BMJ Open Diabetes Res Care 2019; 7:e000721. [PMID: 31908791 PMCID: PMC6936449 DOI: 10.1136/bmjdrc-2019-000721] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/06/2019] [Accepted: 11/11/2019] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE Insulin secretion in sulfonylurea-treated KCNJ11 permanent neonatal diabetes mellitus (PNDM) is thought to be mediated predominantly through amplifying non-KATP-channel pathways such as incretins. Affected individuals report symptoms of postprandial hypoglycemia after eating protein/fat-rich foods. We aimed to assess the physiological response to carbohydrate and protein/fat in people with sulfonylurea-treated KCNJ11 PNDM. RESEARCH DESIGN AND METHODS 5 adults with sulfonylurea-treated KCNJ11 PNDM and five age, sex and body mass index-matched controls without diabetes had a high-carbohydrate and high-protein/fat meal on two separate mornings. Insulin(i) and glucose(g) were measured at baseline then regularly over 4 hours after the meal. Total area under the curve (tAUC) for insulin and glucose was calculated over 4 hours and compared between meals in controls and KCNJ11 cases. RESULTS In controls, glucose values after carbohydrate and protein/fat were similar (median glucose tAUC0-4h21.4 vs 19.7 mmol/L, p=0.08). In KCNJ11 cases glucose levels were higher after carbohydrate than after protein/fat (median glucose tAUC0-4h58.1 vs 31.3 mmol/L, p=0.04). These different glycemic responses reflected different patterns of insulin secretion: in controls, insulin secretion was greatly increased after carbohydrate versus protein/fat (median insulin tAUC0-4h727 vs 335 pmol/L, p=0.04), but in KCNJ11 cases insulin secretion was similar after carbohydrate and protein/fat (median insulin tAUC0-4h327 vs 378 pmol/L, p=0.50). CONCLUSIONS Individuals with sulfonylurea-treated KCNJ11 PNDM produce similar levels of insulin in response to both carbohydrate and protein/fat meals despite carbohydrate resulting in much higher glucose levels and protein/fat resulting in relatively low glucose levels. This suggests in an inability to modulate insulin secretion in response to glucose levels, consistent with a dependence on non-KATP pathways for insulin secretion. TRIAL REGISTRATION NUMBER NCT02921906.
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Affiliation(s)
- Pamela Bowman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Timothy J McDonald
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Bridget A Knight
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Maria Leveridge
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Steve R Spaull
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
| | - Beverley M Shields
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
| | - Suzanne Hammersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Maggie H Shepherd
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Robert C Andrews
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
| | - Kashyap A Patel
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, Devon, UK
- Exeter NIHR Clinical Research Facility, Exeter, Devon, UK
- Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
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Belus MT, Rogers MA, Elzubeir A, Josey M, Rose S, Andreeva V, Yelick PC, Bates EA. Kir2.1 is important for efficient BMP signaling in mammalian face development. Dev Biol 2018; 444 Suppl 1:S297-S307. [PMID: 29571612 PMCID: PMC6148416 DOI: 10.1016/j.ydbio.2018.02.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/23/2022]
Abstract
Mutations that disrupt the inwardly rectifying potassium channel Kir2.1 lead to Andersen-Tawil syndrome that includes periodic paralysis, cardiac arrhythmia, cognitive deficits, craniofacial dysmorphologies and limb defects. The molecular mechanism that underlies the developmental consequences of inhibition of these channels has remained a mystery. We show that while loss of Kir2.1 function does not affect expression of several early facial patterning genes, the domain in which Pou3f3 is expressed in the maxillary arch is reduced. Pou3f3 is important for development of the jugal and squamosal bones. The reduced expression domain of Pou3f3 is consistent with the reduction in the size of the squamosal and jugal bones in Kcnj2KO/KO animals, however it does not account for the diverse craniofacial defects observed in Kcnj2KO/KO animals. We show that Kir2.1 function is required in the cranial neural crest for morphogenesis of several craniofacial structures including palate closure. We find that while the palatal shelves of Kir2.1-null embryos elevate properly, they are reduced in size due to decreased proliferation of the palatal mesenchyme. While we find no reduction in expression of BMP ligands, receptors, and associated Smads in this setting, loss of Kir2.1 reduces the efficacy of BMP signaling as shown by the reduction of phosphorylated Smad 1/5/8 and reduced expression of BMP targets Smad6 and Satb2.
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Affiliation(s)
- Matthew T Belus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Madison A Rogers
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Alaaeddin Elzubeir
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Megan Josey
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Steven Rose
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Viktoria Andreeva
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University, Boston, MA 02111, United States
| | - Pamela C Yelick
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University, Boston, MA 02111, United States
| | - Emily A Bates
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
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Huang Z, Xiao K. Electrophysiological Mechanism of Peripheral Hormones and Nutrients Regulating Energy Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1090:183-198. [PMID: 30390291 DOI: 10.1007/978-981-13-1286-1_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In organism, energy homeostasis is a biological process that involves the coordinated homeostatic regulation of energy intake (food intake) and energy expenditure. The human brain, particularly the hypothalamic proopiomelanocortin (POMC)- and agouti-related protein/neuropeptide Y (AgRP/NPY)-expressing neurons in the arcuate nucleus, plays an essential role in regulating energy homeostasis. The regulation process is mainly dependent upon peripheral hormones such as leptin and insulin, as well as nutrients such as glucose, amino acids, and fatty acids. Although many studies have attempted to illustrate the exact mechanisms of glucose and hormones action on these neurons, we still cannot clearly see the full picture of this regulation action. Therefore, in this review we will mainly discuss those established theories and recent progresses in this area, demonstrating the possible physiological mechanism by which glucose, leptin, and insulin affect neuronal excitability of POMC and AgRP neurons. In addition, we will also focus on some important ion channels which are expressed by POMC and AgRP neurons, such as KATP channels and TRPC channels, and explain how these channels are regulated by peripheral hormones and nutrients and thus regulate energy homeostasis.
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Affiliation(s)
- Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China.
| | - Kuo Xiao
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
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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.
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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
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