1
|
Chen Y, Yin Z, Zhang X, Zhao Y, Liu T, Lu WY, Wang S. Increased GABA signaling in liver macrophage promotes HBV replication in HBV-carrier mice. Virus Res 2024; 344:199366. [PMID: 38548137 PMCID: PMC10998195 DOI: 10.1016/j.virusres.2024.199366] [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: 11/03/2023] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 04/02/2024]
Abstract
Gamma-aminobutyric acid (GABA) signals in various non-neuronal cells including hepatocytes and some immune cells. Studies, including ours, show that type A GABA receptors (GABAARs)-mediated signaling occurs in macrophages regulating tissue-specific functions. Our recent study reveals that activation of GABAARs in liver macrophages promotes their M2-like polarization and increases HBV replication in mice. This short article briefly summarizes the GABA signaling system in macrophages and discusses potential mechanisms by which GABA signaling promotes HBV replication.
Collapse
Affiliation(s)
- Yunling Chen
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Zhaoqing Yin
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Xiaonan Zhang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; School of Clinical and Basic Medical Sciences, Shandong First Medical University& Shandong Academy of Medical Sciences, Jinan, China
| | - Yiwei Zhao
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; School of Clinical and Basic Medical Sciences, Shandong First Medical University& Shandong Academy of Medical Sciences, Jinan, China
| | - Tinghao Liu
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; School of Clinical and Basic Medical Sciences, Shandong First Medical University& Shandong Academy of Medical Sciences, Jinan, China
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, Robarts Research Institute, University of Western Ontario, Canada.
| | - Shuanglian Wang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.
| |
Collapse
|
2
|
Gui L, Tellios V, Xiang YY, Feng Q, Inoue W, Lu WY. Neuronal Nitric Oxide Synthase Regulates Cerebellar Parallel Fiber Slow EPSC in Purkinje Neurons by Modulating STIM1-Gated TRPC3-Containing Channels. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01683-0. [PMID: 38472628 DOI: 10.1007/s12311-024-01683-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 03/14/2024]
Abstract
Responding to burst stimulation of parallel fibers (PFs), cerebellar Purkinje neurons (PNs) generate a convolved synaptic response displaying a fast excitatory postsynaptic current (EPSCFast) followed by a slow EPSC (EPSCSlow). The latter is companied with a rise of intracellular Ca2+ and critical for motor coordination. The genesis of EPSCSlow in PNs results from activation of metabotropic type 1 glutamate receptor (mGluR1), oligomerization of stromal interaction molecule 1 (STIM1) on the membrane of endoplasmic reticulum (ER) and opening of transient receptor potential canonical 3 (TRPC3) channels on the plasma membrane. Neuronal nitric oxide synthase (nNOS) is abundantly expressed in PFs and granule neurons (GNs), catalyzing the production of nitric oxide (NO) hence regulating PF-PN synaptic function. We recently found that nNOS/NO regulates the morphological development of PNs through mGluR1-regulated Ca2+-dependent mechanism. This study investigated the role of nNOS/NO in regulating EPSCSlow. Electrophysiological analyses showed that EPSCSlow in cerebellar slices of nNOS knockout (nNOS-/-) mice was significantly larger than that in wildtype (WT) mice. Activation of mGluR1 in cultured PNs from nNOS-/- mice evoked larger TRPC3-channel mediated currents and intracellular Ca2+ rise than that in PNs from WT mice. In addition, nNOS inhibitor and NO-donor increased and decreased, respectively, the TRPC3-current and Ca2+ rise in PNs. Moreover, the NO-donor effectively decreased TRPC3 currents in HEK293 cells expressing WT STIM1, but not cells expressing a STIM1 with cysteine mutants. These novel findings indicate that nNOS/NO inhibits TRPC3-containig channel mediated cation influx during EPSCSlow, at least in part, by S-nitrosylation of STIM1.
Collapse
Affiliation(s)
- Le Gui
- Robarts Research Institute, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Vasiliki Tellios
- Graduate Program of Neuroscience, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Yun-Yan Xiang
- Robarts Research Institute, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Qingping Feng
- Department of Physiology and Pharmacology, University of Western, Ontario1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Wataru Inoue
- Robarts Research Institute, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
- Graduate Program of Neuroscience, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
- Department of Physiology and Pharmacology, University of Western, Ontario1151 Richmond Street North, London, ON, N6A 5B7, Canada.
| | - Wei-Yang Lu
- Robarts Research Institute, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
- Graduate Program of Neuroscience, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
- Department of Physiology and Pharmacology, University of Western, Ontario1151 Richmond Street North, London, ON, N6A 5B7, Canada.
| |
Collapse
|
3
|
Wu W, Zhang J, Qiao Y, Ren L, Chen Z, Fu Y, Yang Z. Association of long-term benzodiazepine hypnotic use and prediabetes in US population: A cross-sectional analysis of national health and nutrition examination survey data. Medicine (Baltimore) 2023; 102:e35705. [PMID: 37960777 PMCID: PMC10637564 DOI: 10.1097/md.0000000000035705] [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: 07/31/2023] [Accepted: 09/28/2023] [Indexed: 11/15/2023] Open
Abstract
Benzodiazepine hypnotics' effects on glucose metabolism are seldom reported, and the association between long-term (≥4 weeks) benzodiazepine usage and prediabetes has not been studied. This study was aimed to investigate the association between benzodiazepine hypnotic usage for ≥ 3 months and the prevalence of prediabetes. We analyzed cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) during 2005 to 2008, selecting adult participants without diabetes who used benzodiazepine hypnotics for at least 3 months or did not take any hypnotics. Individuals taking other hypnotics, antipsychotics, glucocorticoids, or hypoglycemic drugs were excluded. We defined prediabetes as an hemoglobin A1C (HbA1C) 5.7-6.4%, as suggested by the American Diabetes Association. Prescribed drug information was self-reported and checked by official interviewers, and HbA1C data in NHANES was recognized by the National Glycohemoglobin Standardization Program. We calculated the propensity score according to the covariates and adjusted it using multivariate logistic regression. Lower thresholds of HbA1C ≥ 5.5% or ≥ 5.3% were also analyzed. Among 4694 eligible participants, 38 received benzodiazepine hypnotics; using these hypnotics for ≥ 3 months was not significantly associated with the prevalence of prediabetes, as well as HbA1C ≥ 5.5% or ≥ 5.3%. Adjusted for propensity score, the respective odds ratios for prediabetes, HbA1C ≥ 5.5%, and HbA1C ≥ 5.3% were 1.09 (95% confidence interval [CI] 0.19-6.32), 0.83 (95% CI 0.22-3.13), and 1.22 (95% CI 0.3-4.93). No significant association was found between benzodiazepine hypnotic usage ≥ 3 months and the prevalence of prediabetes.
Collapse
Affiliation(s)
- Weizhen Wu
- Graduate School, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Junning Zhang
- Graduate School, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Yizhuo Qiao
- Graduate School, China Academy of Chinese Medical Science, Beijing, P.R. China
| | - Lijiang Ren
- Graduate School, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Zhe Chen
- Graduate School, Beijing University of Chinese Medicine, Beijing, P.R. China
| | - Yan Fu
- Xiyuan Hospital of China Academy of Chinese Medical Science, Beijing, P.R. China
| | - Zhixu Yang
- Xiyuan Hospital of China Academy of Chinese Medical Science, Beijing, P.R. China
| |
Collapse
|
4
|
Bao Z, Chen X, Li Y, Jiang W, Pan D, Ma L, Wu Y, Chen Y, Chen C, Wang L, Zhao S, Wang T, Lu WY, Ma C, Wang S. The hepatic GABAergic system promotes liver macrophage M2 polarization and mediates HBV replication in mice. Antiviral Res 2023; 217:105680. [PMID: 37494980 DOI: 10.1016/j.antiviral.2023.105680] [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: 02/01/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 07/28/2023]
Abstract
Macrophages display functional phenotypic plasticity. Hepatitis B virus (HBV) infection induces polarizations of liver macrophages either to M1-like pro-inflammatory phenotype or to M2-like anti-inflammatory phenotype. Gamma-aminobutyric acid (GABA) signaling exists in various non-neuronal cells including hepatocytes and some immune cells. Here we report that macrophages express functional GABAergic signaling components and activation of type A GABA receptors (GABAARs) promotes M2-polarization thus advancing HBV replication. Notably, intraperitoneal injection of GABA or the GABAAR agonist muscimol increased HBV replication in HBV-carrier mice that were generated by hydrodynamical injection of adeno-associated virus/HBV1.2 plasmids (pAAV/HBV1.2). The GABA-augmented HBV replication in HBV-carrier mice was significantly reduced by the GABAAR inhibitor picrotoxin although picrotoxin had no significant effect on serum HBsAg levels in control HBV-carrier mice. Depletion of liver macrophages by liposomal clodronate treatment also significantly reduced the GABA-augmented HBV replication. Yet adoptive transfer of liver macrophages isolated from GABA-treated donor HBV-carrier mice into the liposomal clodronate-pretreated recipient HBV-carrier mice restored HBV replication. Moreover, GABA or muscimol treatment increased the expression of "M2" cytokines in macrophages, but had no direct effect on HBV replication in the HepG2.2.15 cells, HBV1.3-transfected Huh7, HepG2, or HepaRG cells, or HBV-infected Huh7-NTCP cells. Taken together, these results suggest that increasing GABA signaling in the liver promotes HBV replication in HBV-carrier mice by suppressing the immunity of liver macrophages, but not by increasing the susceptibility of hepatocytes to HBV infection. Our study shows that a previously unknown GABAergic system in liver macrophage has an essential role in HBV replication.
Collapse
Affiliation(s)
- Ziyou Bao
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Xiaotong Chen
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; Department of Immunology, School of Clinical and Basic Medical Sciences, Shandong First Medical University& Shandong Academy of Medical Sciences, Jinan, China
| | - Yan Li
- Translational Medical Research Centre, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Wenshan Jiang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Di Pan
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China; Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Lushun Ma
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; Department of Paediatric Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Yunxiao Wu
- Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Yunling Chen
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China; Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Chaojia Chen
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Liyuan Wang
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Songbo Zhao
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Tixiao Wang
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, Robarts Research Institute, University of Western Ontario, Canada.
| | - Chunhong Ma
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China.
| | - Shuanglian Wang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.
| |
Collapse
|
5
|
Jin Z, Korol SV. GABA signalling in human pancreatic islets. Front Endocrinol (Lausanne) 2023; 14:1059110. [PMID: 36891061 PMCID: PMC9986413 DOI: 10.3389/fendo.2023.1059110] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023] Open
Abstract
The pancreatic islets are essential microorgans controlling the glucose level in the blood. The islets consist of different cell types which communicate with each other by means of auto- and paracrine interactions. One of the communication molecules produced by and released within the islets is γ-aminobutyric acid (GABA), a well-known inhibitor of neuronal excitability in the mammalian nervous system. Interestingly, GABA is also present in the blood in the nanomolar concentration range. Thus, GABA can affect not only islet function per se (e.g. hormone secretion) but also interactions between immune cells and the pancreatic islet cells in physiological conditions and in pathological states (particularly in type 1 diabetes). In the last decade the interest in GABA signalling in islets has increased. The broad research scope ranges from fundamental physiological studies at the molecular and cellular level to pathological implications and clinical trials. The aim of this mini-review is to outline the current status of the islet GABA field mostly in relation to human islets, to identify the gaps in the current knowledge and what clinical implications GABA signalling may have in islets.
Collapse
|
6
|
Hagan DW, Ferreira SM, Santos GJ, Phelps EA. The role of GABA in islet function. Front Endocrinol (Lausanne) 2022; 13:972115. [PMID: 36246925 PMCID: PMC9558271 DOI: 10.3389/fendo.2022.972115] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Gamma aminobutyric acid (GABA) is a non-proteinogenic amino acid and neurotransmitter that is produced in the islet at levels as high as in the brain. GABA is synthesized by the enzyme glutamic acid decarboxylase (GAD), of which the 65 kDa isoform (GAD65) is a major autoantigen in type 1 diabetes. Originally described to be released via synaptic-like microvesicles or from insulin secretory vesicles, beta cells are now understood to release substantial quantities of GABA directly from the cytosol via volume-regulated anion channels (VRAC). Once released, GABA influences the activity of multiple islet cell types through ionotropic GABAA receptors and metabotropic GABAB receptors. GABA also interfaces with cellular metabolism and ATP production via the GABA shunt pathway. Beta cells become depleted of GABA in type 1 diabetes (in remaining beta cells) and type 2 diabetes, suggesting that loss or reduction of islet GABA correlates with diabetes pathogenesis and may contribute to dysfunction of alpha, beta, and delta cells in diabetic individuals. While the function of GABA in the nervous system is well-understood, the description of the islet GABA system is clouded by differing reports describing multiple secretion pathways and effector functions. This review will discuss and attempt to unify the major experimental results from over 40 years of literature characterizing the role of GABA in the islet.
Collapse
Affiliation(s)
- D. Walker Hagan
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Sandra M. Ferreira
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Gustavo J. Santos
- Islet Biology and Metabolism Lab – I.B.M. Lab, Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina - UFSC, Florianópolis, Brazil
| | - Edward A. Phelps
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| |
Collapse
|
7
|
Pae EK, Chung MK, Harper RM. Intermittent Hypoxia Interferes with Autocrine Effects of GABA on Insulin Secretion in Postnatal Rodents—Implications for Pediatric Obstructive Sleep Apnea. CHILDREN 2022; 9:children9091305. [PMID: 36138614 PMCID: PMC9497165 DOI: 10.3390/children9091305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022]
Abstract
Gamma-amino butyric acid (GABA) is well known to help elevate pancreatic β cell vitality and insulin levels in blood. GABA works via a coupling with GABA receptors; thus, the concentration of GABAA receptors on the plasma membrane of β cells appears to be critical for insulin regulation. Various medical conditions, such as pediatric and adult obstructive sleep apnea (OSA), show high levels of Type 2 diabetes; such patients also are exposed to intermittent hypoxia (IH), which modifies the GABA levels. To evaluate the potential therapeutic roles of GABA for diabetic patients with OSA, we studied the interactions of IH with GABA and GABAA receptors in young rats. Using rat pups and primary pancreatic islets, we evaluated the roles of GABA in insulin secretion. We show that GABA effectively increased the insulin secretion of pancreatic islets under normal ambient oxygen levels, as well as in culture medium with a glucose level of 2 mM. GABA also increased islet insulin secretion conditioned under IH in a 16 mM glucose medium. When islets were IH-treated, insulin secretion decreased due to lower intracellular chloride levels in accordance with the increased KCC2 levels. The results show that IH challenges down-regulate the GABAA receptor levels in pancreatic islets, which decreases GABA–GABAA receptor coupling action, as well as membrane depolarization for insulin secretion. The findings have the potential to suggest novel interventions for insulin regulation during IH of disordered breathing, including OSA.
Collapse
Affiliation(s)
- Eung-Kwon Pae
- School of Dentistry, University of Maryland, Baltimore, MD 21201, USA
- Correspondence:
| | - Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Ronald M. Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
8
|
Rohbeck E, Hasse B, Koopmans G, Romero A, Belgardt BF, Roden M, Eckel J, Romacho T. Positive allosteric γ-aminobutyric acid type A receptor modulation prevents lipotoxicity-induced injury in hepatocytes in vitro. Diabetes Obes Metab 2022; 24:1498-1508. [PMID: 35434888 DOI: 10.1111/dom.14719] [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: 02/16/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 11/29/2022]
Abstract
AIM To determine if a novel positive allosteric modulator of the γ-aminobutyric acid type A (GABAA ) receptor, the thioacrylamide-derivative HK4, which does not penetrate the blood-brain barrier, protects human hepatocytes against lipotoxicity-induced injury. MATERIALS AND METHODS Allosteric modulation of the GABAA receptor by HK4 was determined by patch clamp in HEK-293 cells, calcium influx in INS-1E cells and by using the specific GABAA channel blockers picrotoxin and tert-butylbicyclophosphorothionate (TBPS) in HepG2 cells. Apoptosis was analysed using caspase 3/7, terminal deoxynucleotidyl transferase-dUTP nick end labelling (TUNEL) and array assays in HepG2 cells and/or human primary hepatocytes. Phosphorylation of STAT3 and the NF-κB subunit p65, protein disulphide isomerase (PDI) and poly-ADP-ribose polymerase-1 (PARP-1) was detected by Western blotting. RESULTS Patch clamping, calcium influx measurements and apoptosis assays with the non-competitive GABAA channel blockers picrotoxin and TBPS proved HK4 as a selective positive allosteric modulator of the GABAA receptor. In HepG2 cells, which expressed the main GABAA receptor subunits, HK4 prevented palmitate-induced apoptosis. This protective effect was mediated by downregulation of caspase 3/7 activity and was additionally verified by TUNEL assay. HK4 effectively prevented palmitate-induced apoptosis in human primary hepatocytes. HK4 reduced STAT3 and NF-κB phosphorylation, reduced cleaved PARP-1 expression and upregulated the endoplasmic reticulum (ER) chaperone PDI. CONCLUSIONS HK4 reduced lipotoxic-induced apoptosis by preventing inflammation, DNA damage and ER stress. We propose that the effect of HK4 is mediated by STAT3 and NF-κB. It is suggested that thioacrylamide compounds represent an innovative pharmacological tool to treat or prevent non-alcoholic steatohepatitis as first-in-class drugs.
Collapse
Affiliation(s)
- Elisabeth Rohbeck
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | | | | | - Alejandra Romero
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Bengt-Frederik Belgardt
- Institute for Vascular and Islet Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Düsseldorf, München-Neuherberg, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Düsseldorf, München-Neuherberg, Germany
- Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Jürgen Eckel
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tania Romacho
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| |
Collapse
|
9
|
Kamat V, Radtke JR, Hu Q, Wang W, Sweet IR, Hampe CS. Autoantibodies directed against glutamate decarboxylase interfere with glucose-stimulated insulin secretion in dispersed rat islets. Int J Exp Pathol 2022; 103:140-148. [PMID: 35246889 PMCID: PMC9264341 DOI: 10.1111/iep.12437] [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: 08/18/2021] [Revised: 01/17/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
Islet autoantibodies, including autoantibodies directed against the 65kDa isoform of glutamate decarboxylase (GAD65Ab), are present in the majority of patients with newly diagnosed type 1 diabetes (T1D). Whereas these autoantibodies are historically viewed as an epiphenomenon of the autoimmune response with no significant pathogenic function, we consider in this study the possibility that they impact the major islet function, namely glucose-stimulated insulin secretion. Two human monoclonal GAD65Ab (GAD65 mAb) (b78 and b96.11) were investigated for uptake by live rat beta cells, subcellular localization and their effect on glucose-stimulated insulin secretion. The GAD65 mAbs were internalized by live pancreatic beta cells, where they localized to subcellular structures in an epitope-specific manner. Importantly, GAD65 mAb b78 inhibited, while GAD65 mAb b96.11 enhanced, glucose-stimulated insulin secretion (GSIS). These opposite effects on GSIS rule out non-specific effects of the antibodies and suggest that internalization of the antibody leads to epitope-specific interaction with intracellular machinery regulating insulin granule release. The most likely explanation for the alteration of GSIS by GAD65 Abs is via changes in GABA release due to inhibition or change in GAD65 enzyme activity. This is the first report indicating an active role of GAD65Ab in the pathogenesis of T1D.
Collapse
Affiliation(s)
- Varun Kamat
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Jared R Radtke
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Qingxun Hu
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Wang Wang
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Ian R Sweet
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Christiane S Hampe
- Department of Medicine, University of Washington, Seattle, Washington, USA
| |
Collapse
|
10
|
Shimizu-Okabe C, Okada S, Okamoto S, Masuzaki H, Takayama C. Specific Expression of KCC2 in the α Cells of Normal and Type 1 Diabetes Model Mouse Pancreatic Islets. Acta Histochem Cytochem 2022; 55:47-56. [PMID: 35444351 PMCID: PMC8913275 DOI: 10.1267/ahc.21-00078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/22/2021] [Indexed: 01/14/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the mature brain; however, it acts excitatory during development. This difference in action depends on the intracellular chloride ion concentration, primarily regulated by potassium chloride co-transporter2 (KCC2). Sufficient KCC2 expression results in its inhibitory action. GABA is also abundant in pancreatic islets, where it acts differentially on the islet cells, and is involved in carbohydrate metabolism. However, the mechanisms underlying the differential action remain unknown. We performed immunohistochemistry for glutamic acid decarboxylase (GAD), a synthetic enzyme for GABA, and KCC2 in normal adult islets. GAD was co-localized with insulin in β cells, whereas KCC2 was expressed in glucagon-positive α cells. These results are in line with previous observations that GABA decreases glucagon release but increases insulin release, and suggest that GABA and insulin may work together in reducing blood glucose levels under hyperglycemia. Next, we examined the streptozotocin-induced type1 diabetes mellitus mouse model. GAD and insulin expression levels were markedly decreased. KCC2 was expressed in glucagon-positive cells, whereas insulin- and somatostatin-positive cells were KCC2-negative. These findings suggest that in diabetes model, reduced GABA release may cause disinhibition of glucagon release, resulting in increased blood sugar levels and the maintenance of hyperglycemic state.
Collapse
Affiliation(s)
| | - Shigeki Okada
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus
| | - Shiki Okamoto
- Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology School of Medicine, University of the Ryukyus
| | - Hiroaki Masuzaki
- Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology School of Medicine, University of the Ryukyus
| | - Chitoshi Takayama
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus
| |
Collapse
|
11
|
Pan X, Tao S, Tong N. Potential Therapeutic Targeting Neurotransmitter Receptors in Diabetes. Front Endocrinol (Lausanne) 2022; 13:884549. [PMID: 35669692 PMCID: PMC9163348 DOI: 10.3389/fendo.2022.884549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/19/2022] [Indexed: 12/04/2022] Open
Abstract
Neurotransmitters are signaling molecules secreted by neurons to coordinate communication and proper function among different sections in the central neural system (CNS) by binding with different receptors. Some neurotransmitters as well as their receptors are found in pancreatic islets and are involved in the regulation of glucose homeostasis. Neurotransmitters can act with their receptors in pancreatic islets to stimulate or inhibit the secretion of insulin (β cell), glucagon (α cell) or somatostatin (δ cell). Neurotransmitter receptors are either G-protein coupled receptors or ligand-gated channels, their effects on blood glucose are mainly decided by the number and location of them in islets. Dysfunction of neurotransmitters receptors in islets is involved in the development of β cell dysfunction and type 2 diabetes (T2D).Therapies targeting different transmitter systems have great potential in the prevention and treatment of T2D and other metabolic diseases.
Collapse
Affiliation(s)
- Xiaohui Pan
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Diabetes and Islet Transplantation, Center for Diabetes and Metabolism Research, West China Hospital, Sichuan University, Chengdu, China
| | - Shibing Tao
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Department of Endocrinology, Ziyang First People’s Hospital, Ziyang, China
| | - Nanwei Tong
- Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Diabetes and Islet Transplantation, Center for Diabetes and Metabolism Research, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Nanwei Tong,
| |
Collapse
|
12
|
Hill M, Pařízek A, Šimják P, Koucký M, Anderlová K, Krejčí H, Vejražková D, Ondřejíková L, Černý A, Kancheva R. Steroids, steroid associated substances and gestational diabetes mellitus. Physiol Res 2021. [DOI: 10.33549//physiolres.934794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
As gestational diabetes mellitus (GDM) is both a frequent and serious complication, steroid levels in pregnancy are extremely elevated and their role in pregnancy is crucial, this review focuses on the role of steroids and related substances in the GDM pathophysiology. Low SHBG levels are associated with insulin resistance and hyperinsulinemia, while also predicting a predisposition to GDM. Other relevant agents are placental hormones such as kisspeptin and CRH, playing also an important role beyond pregnancy, but which are synthesized here in smaller amounts in the hypothalamus. These hormones affect both the course of pregnancy as well as the synthesis of pregnancy steroids and may also be involved in the GDM pathophysiology. Steroids, whose biosynthesis is mainly provided by the fetal adrenal glands, placenta, maternal adrenal glands, and both maternal and fetal livers, are also synthesized in limited amounts directly in the pancreas and may influence the development of GDM. These substances involve the sulfated Δ5 steroids primarily acting via modulating different ion channels and influencing the development of GDM in different directions, mostly diabetogenic progesterone and predominantly anti-diabetic estradiol acting both in genomic and non-genomic way, androgens associated with IR and hyperinsulinemia, neuroactive steroids affecting the pituitary functioning, and cortisol whose production is stimulated by CRH but which suppresses its pro-inflammatory effects. Due to the complex actions of steroids, studies assessing their predominant effect and studies assessing their predictive values for estimating predisposition to GDM are needed.
Collapse
Affiliation(s)
- M Hill
- Institute of Endocrinology, Prague, Czech Republic.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Ondřejíková L, Pařízek A, Šimják P, Vejražková D, Velíková M, Anderlová K, Vosátková M, Krejčí H, Koucký M, Kancheva R, Dušková M, Vaňková M, Bulant J, Hill M. Altered Steroidome in Women with Gestational Diabetes Mellitus: Focus on Neuroactive and Immunomodulatory Steroids from the 24th Week of Pregnancy to Labor. Biomolecules 2021; 11:biom11121746. [PMID: 34944390 PMCID: PMC8698588 DOI: 10.3390/biom11121746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/12/2021] [Accepted: 11/20/2021] [Indexed: 12/19/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is a complication in pregnancy, but studies focused on the steroidome in patients with GDM are not available in the public domain. This article evaluates the steroidome in GDM+ and GDM- women and its changes from 24 weeks (± of gestation) to labor. The study included GDM+ (n = 44) and GDM- women (n = 33), in weeks 24-28, 30-36 of gestation and at labor and mixed umbilical blood after delivery. Steroidomic data (101 steroids quantified by GC-MS/MS) support the concept that the increasing diabetogenic effects with the approaching term are associated with mounting progesterone levels. The GDM+ group showed lower levels of testosterone (due to reduced AKR1C3 activity), estradiol (due to a shift from the HSD17B1 towards HSD17B2 activity), 7-oxygenated androgens (competing with cortisone for HSD11B1 and shifting the balance from diabetogenic cortisol towards the inactive cortisone), reduced activities of SRD5As, and CYP17A1 in the hydroxylase but higher CYP17A1 activity in the lyase step. With the approaching term, the authors found rising activities of CYP3A7, AKR1C1, CYP17A1 in its hydroxylase step, but a decline in its lyase step, rising conjugation of neuroinhibitory and pregnancy-stabilizing steroids and weakening AKR1D1 activity.
Collapse
Affiliation(s)
- Leona Ondřejíková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Antonín Pařízek
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Patrik Šimják
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Daniela Vejražková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Marta Velíková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Kateřina Anderlová
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Michala Vosátková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Hana Krejčí
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Michal Koucký
- Department of Gynecology and Obstetrics, First Faculty of Medicine, General University Hospital in Prague, Charles University in Prague, 128 08 Prague, Czech Republic; (A.P.); (P.Š.); (K.A.); (H.K.); (M.K.)
| | - Radmila Kancheva
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Michaela Dušková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Markéta Vaňková
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Josef Bulant
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
| | - Martin Hill
- Institute of Endocrinology, 116 94 Prague, Czech Republic; (L.O.); (D.V.); (M.V.); (M.V.); (R.K.); (M.D.); (M.V.); (J.B.)
- Correspondence: ; Tel.: +420-224-905-246
| |
Collapse
|
14
|
O'Kell AL, Wasserfall C, Guingab-Cagmat J, Webb-Roberston BJM, Atkinson MA, Garrett TJ. Targeted metabolomic analysis identifies increased serum levels of GABA and branched chain amino acids in canine diabetes. Metabolomics 2021; 17:100. [PMID: 34775536 PMCID: PMC8693811 DOI: 10.1007/s11306-021-01850-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Dogs with naturally occurring diabetes mellitus represent a potential model for human type 1 diabetes, yet significant knowledge voids exist in terms of the pathogenic mechanisms underlying the canine disorder. Untargeted metabolomic studies from a limited number of diabetic dogs identified similarities to humans with the disease. OBJECTIVE To expand and validate earlier metabolomic studies, identify metabolites that differ consistently between diabetic and healthy dogs, and address whether certain metabolites might serve as disease biomarkers. METHODS Untargeted metabolomic analysis via liquid chromatography-mass spectrometry was performed on serum from diabetic (n = 15) and control (n = 15) dogs. Results were combined with those of our previously published studies using identical methods (12 diabetic and 12 control dogs) to identify metabolites consistently different between the groups in all 54 dogs. Thirty-two candidate biomarkers were quantified using targeted metabolomics. Biomarker concentrations were compared between the groups using multiple linear regression (corrected P < 0.0051 considered significant). RESULTS Untargeted metabolomics identified multiple persistent differences in serum metabolites in diabetic dogs compared with previous studies. Targeted metabolomics showed increases in gamma amino butyric acid, valine, leucine, isoleucine, citramalate, and 2-hydroxyisobutyric acid in diabetic versus control dogs while indoxyl sulfate, N-acetyl-L-aspartic acid, kynurenine, anthranilic acid, tyrosine, glutamine, and tauroursodeoxycholic acid were decreased. CONCLUSION Several of these findings parallel metabolomic studies in both human diabetes and other animal models of this disease. Given recent studies on the role of GABA and branched chain amino acids in human diabetes, the increase in serum concentrations in canine diabetes warrants further study of these metabolites as potential biomarkers, and to identify similarity in mechanisms underlying this disease in humans and dogs.
Collapse
Affiliation(s)
- Allison L O'Kell
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, The University of Florida, 2015 SW 16th Ave, Box 100116, Gainesville, FL, 32608, USA.
| | - Clive Wasserfall
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida, Gainesville, FL, USA
| | - Joy Guingab-Cagmat
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, The University of Florida, Gainesville, FL, USA
| | - Bobbie-Jo M Webb-Roberston
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida, Gainesville, FL, USA
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mark A Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida, Gainesville, FL, USA
| | - Timothy J Garrett
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida, Gainesville, FL, USA
| |
Collapse
|
15
|
Rezazadeh H, Sharifi MR, Soltani N. Insulin resistance and the role of gamma-aminobutyric acid. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2021; 26:39. [PMID: 34484371 PMCID: PMC8384006 DOI: 10.4103/jrms.jrms_374_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 12/09/2020] [Accepted: 02/02/2021] [Indexed: 12/17/2022]
Abstract
Insulin resistance (IR) is mentioned to be a disorder in insulin ability in insulin-target tissues. Skeletal muscle (SkM) and liver function are more affected by IR than other insulin target cells. SkM is the main site for the consumption of ingested glucose. An effective treatment for IR has two properties: An inhibition of β-cell death and a promotion of β-cell replication. Gamma-aminobutyric acid (GABA) can improve beta-cell mass and function. Multiple studies have shown that GABA decreases IR probably via increase in glucose transporter 4 (GLUT4) gene expression and prevention of gluconeogenesis pathway in the liver. This review focused on the general aspects of IR in skeletal muscle (SkM), liver; the cellular mechanism(s) lead to the development of IR in these organs, and the role of GABA to reduce insulin resistance.
Collapse
Affiliation(s)
- Hossein Rezazadeh
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Mohammad Reza Sharifi
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Nepton Soltani
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| |
Collapse
|
16
|
Integrated Metabolomics and Proteomics Analyses in the Local Milieu of Islet Allografts in Rejection versus Tolerance. Int J Mol Sci 2021; 22:ijms22168754. [PMID: 34445459 PMCID: PMC8395897 DOI: 10.3390/ijms22168754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/03/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
An understanding of the immune mechanisms that lead to rejection versus tolerance of allogeneic pancreatic islet grafts is of paramount importance, as it facilitates the development of innovative methods to improve the transplant outcome. Here, we used our established intraocular islet transplant model to gain novel insight into changes in the local metabolome and proteome within the islet allograft’s immediate microenvironment in association with immune-mediated rejection or tolerance. We performed integrated metabolomics and proteomics analyses in aqueous humor samples representative of the graft’s microenvironment under each transplant outcome. The results showed that several free amino acids, small primary amines, and soluble proteins related to the Warburg effect were upregulated or downregulated in association with either outcome. In general, the observed shifts in the local metabolite and protein profiles in association with rejection were consistent with established pro-inflammatory metabolic pathways and those observed in association with tolerance were immune regulatory. Taken together, the current findings further support the potential of metabolic reprogramming of immune cells towards immune regulation through targeted pharmacological and dietary interventions against specific metabolic pathways that promote the Warburg effect to prevent the rejection of transplanted islets and promote their immune tolerance.
Collapse
|
17
|
Lorenzo PI, Cobo-Vuilleumier N, Martín-Vázquez E, López-Noriega L, Gauthier BR. Harnessing the Endogenous Plasticity of Pancreatic Islets: A Feasible Regenerative Medicine Therapy for Diabetes? Int J Mol Sci 2021; 22:4239. [PMID: 33921851 PMCID: PMC8073058 DOI: 10.3390/ijms22084239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/16/2021] [Accepted: 04/16/2021] [Indexed: 12/15/2022] Open
Abstract
Diabetes is a chronic metabolic disease caused by an absolute or relative deficiency in functional pancreatic β-cells that leads to defective control of blood glucose. Current treatments for diabetes, despite their great beneficial effects on clinical symptoms, are not curative treatments, leading to a chronic dependence on insulin throughout life that does not prevent the secondary complications associated with diabetes. The overwhelming increase in DM incidence has led to a search for novel antidiabetic therapies aiming at the regeneration of the lost functional β-cells to allow the re-establishment of the endogenous glucose homeostasis. Here we review several aspects that must be considered for the development of novel and successful regenerative therapies for diabetes: first, the need to maintain the heterogeneity of islet β-cells with several subpopulations of β-cells characterized by different transcriptomic profiles correlating with differences in functionality and in resistance/behavior under stress conditions; second, the existence of an intrinsic islet plasticity that allows stimulus-mediated transcriptome alterations that trigger the transdifferentiation of islet non-β-cells into β-cells; and finally, the possibility of using agents that promote a fully functional/mature β-cell phenotype to reduce and reverse the process of dedifferentiation of β-cells during diabetes.
Collapse
Affiliation(s)
- Petra I. Lorenzo
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain; (N.C.-V.); (E.M.-V.); (L.L.-N.)
| | - Nadia Cobo-Vuilleumier
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain; (N.C.-V.); (E.M.-V.); (L.L.-N.)
| | - Eugenia Martín-Vázquez
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain; (N.C.-V.); (E.M.-V.); (L.L.-N.)
| | - Livia López-Noriega
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain; (N.C.-V.); (E.M.-V.); (L.L.-N.)
| | - Benoit R. Gauthier
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Junta de Andalucía-University of Pablo de Olavide-University of Seville-CSIC, 41092 Seville, Spain; (N.C.-V.); (E.M.-V.); (L.L.-N.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 028029 Madrid, Spain
| |
Collapse
|
18
|
Untereiner A, Xu J, Bhattacharjee A, Cabrera O, Hu C, Dai FF, Wheeler MB. γ-aminobutyric acid stimulates β-cell proliferation through the mTORC1/p70S6K pathway, an effect amplified by Ly49, a novel γ-aminobutyric acid type A receptor positive allosteric modulator. Diabetes Obes Metab 2020; 22:2021-2031. [PMID: 32558194 DOI: 10.1111/dom.14118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 12/15/2022]
Abstract
AIM To examine the mechanism of action of γ-aminobutyric acid (GABA) on β-cell proliferation and investigate if co-treatment with Ly49, a novel GABA type A receptor positive allosteric modulator (GABAA -R PAM), amplifies this effect. METHODS Human or mouse islets were co-treated for 4-5 days with GABA and selected receptor or cell signalling pathway modulators. Immunofluorescence was used to determine protein co-localization, cell number or proliferation, and islet size. Osmotic minipumps were surgically implanted in mice to assess Ly49 effects on pancreatic β-cells. RESULTS Amplification of GABAA -R signalling enhanced GABA-stimulated β-cell proliferation in cultured mouse islets. Co-treatment of GABA with an inhibitor specific for PI3K, mTORC1/2, or p70S6K, abolished GABA-stimulated β-cell proliferation in mouse and human islets. Nuclear p-AktSer473 and p-p70S6KThr421/Ser424 expression in pancreatic β-cells was increased in GABA-treated mice compared with vehicle-treated mice, an effect augmented with GABA and Ly49 co-treatment. Mice co-treated with GABA and Ly49 exhibited enhanced β-cell area and proliferation compared with GABA-treated mice. Furthermore, S961 injection (an insulin receptor antagonist) resulted in enhanced plasma insulin in GABA and Ly49 co-treated mice compared with GABA-treated mice. Importantly, GABA co-treated with Ly49 increased β-cell proliferation in human islets providing a potential application for human subjects. CONCLUSIONS We show that GABA stimulates β-cell proliferation via the PI3K/mTORC1/p70S6K pathway in both mouse and human islets. Furthermore, we show that Ly49 enhances the β-cell regenerative effects of GABA, showing potential in the intervention of diabetes.
Collapse
Affiliation(s)
- Ashley Untereiner
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jie Xu
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Key Clinical Center for Metabolic Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Alpana Bhattacharjee
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Over Cabrera
- Diabetes and Complications Research, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana, USA
| | - Cheng Hu
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Key Clinical Center for Metabolic Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- Institute for Metabolic Disease, Fengxian Central Hospital Affiliated to Southern Medical University, Shanghai, China
| | - Feihan F Dai
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Michael B Wheeler
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| |
Collapse
|
19
|
Park NH, Lee SJ, Mechesso AF, Boby N, Yixian Q, Yoon WK, Lee SP, Lee JS, Park SC. Hepatoprotective effects of gamma-aminobutyric acid-enriched fermented Hovenia dulcis extract on ethanol-induced liver injury in mice. BMC Complement Med Ther 2020; 20:75. [PMID: 32143613 PMCID: PMC7076742 DOI: 10.1186/s12906-020-2866-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 02/26/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Various extracts of Hovenia dulcis have been commonly used in Asia for cases of alcohol-related disorders. Fermentation is reported to enhance the level and biological activities of various bio-constituents of plant extracts. Therefore, this study was undertaken to evaluate the effects of fermented H. dulcis extract (FHDE) on ethanol-induced liver injury in mice. METHODS FHDE was prepared using Bacillus subtilis and Lactobacillus plantarum. The effects of FHDE on ethanol-induced liver injury were evaluated in C57BL/6 N CrSlc mice. A mixed feed preparation containing the fermented extract with and without ethanol was given to mice for 29 days, according to its group. At the end of the experiment, blood and liver samples were collected from all mice in the group. Plasma biochemical analysis and histopathological investigation were performed to evaluate the impacts of treatment on the biomarkers of hepatic damage and inflammatory changes. Besides, the expression of genes that regulate the activities of enzymes associated with alcohol metabolism, antioxidant activity, and fatty acid oxidation was assessed using a quantitative real-time polymerase chain reaction. Moreover, the amino acid contents and the active ingredients of the extract were evaluated before and after fermentation. RESULTS Fermentation resulted in a marked increase and decrease in the amount of Gamma-Amino-n-butyric acid (GABA) and glutamic acid, respectively. FHDE enhanced the body weight gain of mice compared to ethanol. Besides, plasma levels of triglyceride, low-density lipoprotein, the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly (P < 0.05) reduced in the FHDE-treated groups relative to the ethanol-treated control. FHDE upregulated the expression of genes associated with enzymes involved in alcohol dehydrogenation (Adh1 and Aldh2), antioxidant activity (SOD and CAT), and fatty acid oxidation (PPAR-α and PGC-1α). However, the expressions of Cytochrome peroxidase Cyp2E1 and genes related to lipogenesis (SREBP-1c, FAS, SCD-1, and ACC) were significantly (P < 0.05) downregulated following treatment with the FHDE. Histopathological investigation demonstrated a slight degree of inflammatory cell infiltration and occasional fatty changes in the FHDE-treated groups. CONCLUSION The GABA-enriched fermented H. dulcis extract prevented ethanol-induced hepatic damage by enhancing the antioxidant defense system, fatty acid oxidation, and reducing lipogenesis.
Collapse
Affiliation(s)
- Na-Hye Park
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Seung-Jin Lee
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Abraham Fikru Mechesso
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Naila Boby
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Quah Yixian
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Woong-Kyu Yoon
- Department of Food Science and Technology, Keimyung University, Daegu, 42601 Republic of Korea
| | - Sam-Pin Lee
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| | - Jong-Suk Lee
- Biocenter, Gyeonggido Business and Science Accelerator (GBSA), Suwon, Gyeonggi-do 16229 Republic of Korea
| | - Seung-Chun Park
- College of Veterinary Medicine, Kyungpook National University, 80, Daehak-ro, Buk-gu, 41566 Daegu, Republic of Korea
| |
Collapse
|
20
|
Chloride transporters and channels in β-cell physiology: revisiting a 40-year-old model. Biochem Soc Trans 2020; 47:1843-1855. [PMID: 31697318 PMCID: PMC6925527 DOI: 10.1042/bst20190513] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022]
Abstract
It is accepted that insulin-secreting β-cells release insulin in response to glucose even in the absence of functional ATP-sensitive K+ (KATP)-channels, which play a central role in a 'consensus model' of secretion broadly accepted and widely reproduced in textbooks. A major shortcoming of this consensus model is that it ignores any and all anionic mechanisms, known for more than 40 years, to modulate β-cell electrical activity and therefore insulin secretion. It is now clear that, in addition to metabolically regulated KATP-channels, β-cells are equipped with volume-regulated anion (Cl-) channels (VRAC) responsive to glucose concentrations in the range known to promote electrical activity and insulin secretion. In this context, the electrogenic efflux of Cl- through VRAC and other Cl- channels known to be expressed in β-cells results in depolarization because of an outwardly directed Cl- gradient established, maintained and regulated by the balance between Cl- transporters and channels. This review will provide a succinct historical perspective on the development of a complex hypothesis: Cl- transporters and channels modulate insulin secretion in response to nutrients.
Collapse
|
21
|
Wang Y, Wang A, Alkhalidy H, Luo J, Moomaw E, Neilson AP, Liu D. Flavone Hispidulin Stimulates Glucagon-Like Peptide-1 Secretion and Ameliorates Hyperglycemia in Streptozotocin-Induced Diabetic Mice. Mol Nutr Food Res 2020; 64:e1900978. [PMID: 31967385 DOI: 10.1002/mnfr.201900978] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 12/24/2019] [Indexed: 12/17/2022]
Abstract
SCOPE Loss of functional β-cell mass is central for the deterioration of glycemic control in diabetes. The incretin hormone glucagon-like peptide-1 (GLP-1) plays a critical role in maintaining glycemic homeostasis via potentiating glucose-stimulated insulin secretion and promoting β-cell mass. Agents that can directly promote GLP-1 secretion, thereby increasing insulin secretion and preserving β-cell mass, hold great potential for the treatment of T2D. METHODS AND RESULTS GluTag L-cells, INS832/13 cells, and mouse ileum crypts and islets are cultured for examining the effects of flavone hispidulin on GLP-1 and insulin secretion. Mouse livers and isolated hepatocytes are used for gluconeogenesis. Streptozotocin-induced diabetic mice are treated with hispidulin (20 mg kg-1 day-1 , oral gavage) for 6 weeks to evaluate its anti-diabetic potential. Hispidulin stimulates GLP-1 secretion from the L-cell line, ileum crypts, and in vivo. This hispidulin action is mediated via activation of cyclic adenosine monophosphate/protein kinase A signaling. Hispidulin significantly improves glycemic control in diabetic mice, concomitant with improved insulin release, and β-cell survival. Additionally, hispidulin decreases hepatic pyruvate carboxylase expression in diabetic mice and suppresses gluconeogenesis in hepatocytes. Furthermore, hispidulin stimulates insulin secretion from β-cells. CONCLUSION These findings suggest that Hispidulin may be a novel dual-action anti-diabetic compound via stimulating GLP-1 secretion and suppressing hepatic glucose production.
Collapse
Affiliation(s)
- Yao Wang
- Department of Human Nutrition, Foods, and Exercise, College of Agricultural and Life Sciences, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Aiping Wang
- College of Life Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, China
| | - Hana Alkhalidy
- Department of Nutrition and Food Technology, Jordan University of Science and Technology, Irbid, 22110, Jordan
| | - Jing Luo
- Department of Human Nutrition, Foods, and Exercise, College of Agricultural and Life Sciences, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Elizabeth Moomaw
- Department of Human Nutrition, Foods, and Exercise, College of Agricultural and Life Sciences, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Andrew P Neilson
- Plants for Human Health Institution, North Carolina State University, Kannapolis, NC, 28081, USA
| | - Dongmin Liu
- Department of Human Nutrition, Foods, and Exercise, College of Agricultural and Life Sciences, Virginia Tech, Blacksburg, VA, 24060, USA
| |
Collapse
|
22
|
Yi Z, Waseem Ghani M, Ghani H, Jiang W, Waseem Birmani M, Ye L, Bin L, Cun LG, Lilong A, Mei X. Gimmicks of gamma-aminobutyric acid (GABA) in pancreatic β-cell regeneration through transdifferentiation of pancreatic α- to β-cells. Cell Biol Int 2020; 44:926-936. [PMID: 31903671 DOI: 10.1002/cbin.11302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/04/2020] [Indexed: 02/06/2023]
Abstract
In vivo regeneration of lost or dysfunctional islet β cells can fulfill the promise of improved therapy for diabetic patients. To achieve this, many mitogenic factors have been attempted, including gamma-aminobutyric acid (GABA). GABA remarkably affects pancreatic islet cells' (α cells and β cells) function through paracrine and/or autocrine binding to its membrane receptors on these cells. GABA has also been studied for promoting the transformation of α cells to β cells. Nonetheless, the gimmickry of GABA-induced α-cell transformation to β cells has two different perspectives. On the one hand, GABA was found to induce α-cell transformation to β cells in vivo and insulin-secreting β-like cells in vitro. On the other hand, GABA treatment showed that it has no α- to β-cell transformation response. Here, we will summarize the physiological effects of GABA on pancreatic islet β cells with an emphasis on its regenerative effects for transdifferentiation of islet α cells to β cells. We will also critically discuss the controversial results about GABA-mediated transdifferentiation of α cells to β cells.
Collapse
Affiliation(s)
- Zhao Yi
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Muhammad Waseem Ghani
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Hammad Ghani
- Nawaz Sharif Medical College, University of Gujrat, Punjab, 50180, Pakistan
| | - Wu Jiang
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Muhammad Waseem Birmani
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Li Ye
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Liu Bin
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Lang Guan Cun
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - An Lilong
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Xiao Mei
- Department of Animal Science and Medicine, Agricultural College, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.,Department of Animal Breeding, Genetics and Reproduction, Agricultural Collage, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| |
Collapse
|
23
|
Kusunoki M, Hayashi M, Shoji T, Uba T, Tanaka H, Sumi C, Matsuo Y, Hirota K. Propofol inhibits stromatoxin-1-sensitive voltage-dependent K + channels in pancreatic β-cells and enhances insulin secretion. PeerJ 2019; 7:e8157. [PMID: 31824770 PMCID: PMC6894434 DOI: 10.7717/peerj.8157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Background Proper glycemic control is an important goal of critical care medicine, including perioperative patient care that can influence patients’ prognosis. Insulin secretion from pancreatic β-cells is generally assumed to play a critical role in glycemic control in response to an elevated blood glucose concentration. Many animal and human studies have demonstrated that perioperative drugs, including volatile anesthetics, have an impact on glucose-stimulated insulin secretion (GSIS). However, the effects of the intravenous anesthetic propofol on glucose metabolism and insulin sensitivity are largely unknown at present. Methods The effect of propofol on insulin secretion under low glucose or high glucose was examined in mouse MIN6 cells, rat INS-1 cells, and mouse pancreatic β-cells/islets. Cellular oxygen or energy metabolism was measured by Extracellular Flux Analyzer. Expression of glucose transporter 2 (GLUT2), potassium channels, and insulin mRNA was assessed by qRT-PCR. Protein expression of voltage-dependent potassium channels (Kv2) was also assessed by immunoblot. Propofol’s effects on potassium channels including stromatoxin-1-sensitive Kv channels and cellular oxygen and energy metabolisms were also examined. Results We showed that propofol, at clinically relevant doses, facilitates insulin secretion under low glucose conditions and GSIS in MIN6, INS-1 cells, and pancreatic β-cells/islets. Propofol did not affect intracellular ATP or ADP concentrations and cellular oxygen or energy metabolism. The mRNA expression of GLUT2 and channels including the voltage-dependent calcium channels Cav1.2, Kir6.2, and SUR1 subunit of KATP, and Kv2 were not affected by glucose or propofol. Finally, we demonstrated that propofol specifically blocks Kv currents in β-cells, resulting in insulin secretion in the presence of glucose. Conclusions Our data support the hypothesis that glucose induces membrane depolarization at the distal site, leading to KATP channel closure, and that the closure of Kv channels by propofol depolarization in β-cells enhances Ca2+ entry, leading to insulin secretion. Because its activity is dependent on GSIS, propofol and its derivatives are potential compounds that enhance and initiate β-cell electrical activity.
Collapse
Affiliation(s)
- Munenori Kusunoki
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Mikio Hayashi
- Department of Cell Physiology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Tomohiro Shoji
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Takeo Uba
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Hiromasa Tanaka
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Chisato Sumi
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Yoshiyuki Matsuo
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Kiichi Hirota
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| |
Collapse
|
24
|
Tian J, Dang H, O'Laco KA, Song M, Tiu BC, Gilles S, Zakarian C, Kaufman DL. Homotaurine Treatment Enhances CD4 + and CD8 + Regulatory T Cell Responses and Synergizes with Low-Dose Anti-CD3 to Enhance Diabetes Remission in Type 1 Diabetic Mice. Immunohorizons 2019; 3:498-510. [PMID: 31636084 PMCID: PMC6823932 DOI: 10.4049/immunohorizons.1900019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 10/02/2019] [Indexed: 12/16/2022] Open
Abstract
Immune cells express γ-aminobutyric acid receptors (GABA-R), and GABA administration can inhibit effector T cell responses in models of autoimmune disease. The pharmacokinetic properties of GABA, however, may be suboptimal for clinical applications. The amino acid homotaurine is a type A GABA-R (GABAA-R) agonist with good pharmacokinetics and appears safe for human consumption. In this study, we show that homotaurine inhibits in vitro T cell proliferation to a similar degree as GABA but at lower concentrations. In vivo, oral homotaurine treatment had a modest ability to reverse hyperglycemia in newly hyperglycemic NOD mice but was ineffective after the onset of severe hyperglycemia. In severely diabetic NOD mice, the combination of homotaurine and low-dose anti-CD3 treatment significantly increased 1) disease remission, 2) the percentages of splenic CD4+ and CD8+ regulatory T cells compared with anti-CD3 alone, and 3) the frequencies of CD4+ and CD8+ regulatory T cells in the pancreatic lymph nodes compared with homotaurine monotherapy. Histological examination of their pancreata provided no evidence of the large-scale GABAA-R agonist–mediated replenishment of islet β-cells that has been reported by others. However, we did observe a few functional islets in mice that received combined therapy. Thus, GABAA-R activation enhanced CD4+ and CD8+ regulatory T cell responses following the depletion of effector T cells, which was associated with the preservation of some functional islets. Finally, we observed that homotaurine treatment enhanced β-cell replication and survival in a human islet xenograft model. Hence, GABAA-R agonists, such as homotaurine, are attractive candidates for testing in combination with other therapeutic agents in type 1 diabetes clinical trials.
Collapse
Affiliation(s)
- Jide Tian
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Hoa Dang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Karen Anne O'Laco
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Min Song
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Bryan-Clement Tiu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Spencer Gilles
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Christina Zakarian
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| | - Daniel L Kaufman
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
25
|
Wang Q, Ren L, Wan Y, Prud'homme GJ. GABAergic regulation of pancreatic islet cells: Physiology and antidiabetic effects. J Cell Physiol 2019; 234:14432-14444. [PMID: 30693506 DOI: 10.1002/jcp.28214] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/15/2019] [Indexed: 01/24/2023]
Abstract
Diabetes occurs when pancreatic β-cell death exceeds β-cell growth, which leads to loss of β-cell mass. An effective therapy must have two actions: promotion of β-cell replication and suppression of β-cell death. Previous studies have established an important role for γ-aminobutyric acid (GABA) in islet-cell hormone homeostasis, as well as the maintenance of the β-cell mass. GABA exerts paracrine actions on α cells in suppressing glucagon secretion, and it has autocrine actions on β cells that increase insulin secretion. Multiple studies have shown that GABA increases the mitotic rate of β cells. In mice, following β-cell depletion with streptozotocin, GABA therapy can restore the β-cell mass. Enhanced β-cell replication appears to depend on growth and survival pathways involving Akt activation. Some studies have also suggested that it induces transdifferentiation of α cells into β cells, but this has been disputed and requires further investigation. In addition to proliferative effects, GABA protects β cells against injury and markedly reduces their apoptosis under a variety of conditions. The antiapoptotic effects depend at least in part on the enhancement of sirtuin-1 and Klotho activity, which both inhibit activation of the NF-κB inflammatory pathway. Importantly, in xenotransplanted human islets, GABA therapy stimulates β-cell replication and insulin secretion. Thus, the intraislet GABAergic system is a target for the amelioration of diabetes therapy, including β-cell survival and regeneration. GABA (or GABAergic drugs) can be combined with other antidiabetic drugs for greater effect.
Collapse
Affiliation(s)
- Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Liwei Ren
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China
| | - Yun Wan
- Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China
| | - Gerald J Prud'homme
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine, St. Michael's Hospital, Toronto, Ontario, Canada
| |
Collapse
|
26
|
Ren L, Cui Q, Liu W, Wang L, Liao Y, Feng Y, Sun W, Yang Y, Zhang Z, Jin T, Prud'homme GJ, Zhang L, Li Y, Leng Y, Wang Q. Novel GLP-1 Analog Supaglutide Stimulates Insulin Secretion in Mouse and Human Islet Beta-Cells and Improves Glucose Homeostasis in Diabetic Mice. Front Physiol 2019; 10:930. [PMID: 31404283 PMCID: PMC6670290 DOI: 10.3389/fphys.2019.00930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/09/2019] [Indexed: 12/11/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1), an incretin hormone plays an important role in regulating glucose homeostasis. The therapeutic use of native GLP-1 is inadequate due to its short in vivo half-life. We recently developed a novel GLP-1 mimetics supaglutide, and demonstrated that this formulation retained native GLP-1 biological activities and possessed long-lasting GLP-1 actions. In this study, we further examined its abilities in regulating blood glucose in diabetic mice. We found that supaglutide stimulated insulin secretion in both mouse and human islets in a dose-dependent fashion. Oral glucose tolerance test conducted in normal ICR mice showed that supaglutide significantly decreased postprandial glucose excursions in a dose-dependent fashion. In type 2 diabetic db/db mice, a single-dose injection of supaglutide significantly decreased blood glucose levels, and this efficacy was lasted for at least 72 h in a dose-dependent fashion. During a 4-weeks intervention course supaglutide (twice injections per week) dose-dependently and significantly decreased fasting and random blood glucose levels in hyperglycemic db/db mice. Supaglutide, at a dose of 1.2 mg/kg, significantly reduced serum fructosamine levels. This was associated with significant enlargement of beta-cell mass, increased pancreatic insulin content, and increased plasma insulin level. Notably, during the intervention course supaglutide significantly reduced body-weight gain in these obese diabetic mice, associated with reduced fat mass (but not the lean mass), improved lipid profile, i.e., declined serum triglyceride, and free fatty acid levels compared to the placebo control. These finding reveals that supaglutide exerts beneficial effects in regulating blood glucose and lipid homeostasis in diabetic db/db mice.
Collapse
Affiliation(s)
- Liwei Ren
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiaoli Cui
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Wenjuan Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Liqian Wang
- Shanghai Yinuo Pharmaceutical Co., Ltd., Shanghai, China
| | - Yijing Liao
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Ying Feng
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wanwan Sun
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yehong Yang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhaoyun Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Tianru Jin
- Division of Advanced Diagnostics, Toronto General Research Institute, University Health Network, Toronto, ON, Canada.,Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Gerald J Prud'homme
- Department of Laboratory Medicine and Pathobiology, Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Lina Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yiming Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Ying Leng
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| |
Collapse
|
27
|
Wu W, Qiu J, Wang A, Li Z. Impact of whole cereals and processing on type 2 diabetes mellitus: a review. Crit Rev Food Sci Nutr 2019; 60:1447-1474. [DOI: 10.1080/10408398.2019.1574708] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Weijing Wu
- College of Food Science and Nutritional Engineering, China Agricultural University, Haidian, Beijing, China
- Laboratory of nutrition and food safety, Xiamen Medical College, Xiamen, Fujian, China
| | - Ju Qiu
- Ministry of Agriculture, Institute of Food and Nutrition Development, Haidian, Beijing, China
| | - Aili Wang
- Department of Food Science and Technology, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Zaigui Li
- College of Food Science and Nutritional Engineering, China Agricultural University, Haidian, Beijing, China
| |
Collapse
|
28
|
Tang X, Yu R, Zhou Q, Jiang S, Le G. Protective effects of γ-aminobutyric acid against H 2O 2-induced oxidative stress in RIN-m5F pancreatic cells. Nutr Metab (Lond) 2018; 15:60. [PMID: 30202421 PMCID: PMC6122738 DOI: 10.1186/s12986-018-0299-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/26/2018] [Indexed: 11/30/2022] Open
Abstract
Background γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the central nervous system and reported to maintain the redox homeostasis and insulin secretion function of pancreatic β cells. This study tested the hypothesis that GABA maintains cellular redox status, and modulates glycogen synthase kinase (GSK)-3β and antioxidant-related nuclear factor erythroid 2-related factor 2 (NRF2) nuclear mass ratio in the H2O2-injured RINm5F cells. Methods RINm5F cells were treated with/without GABA (50, 100 and 200 μmol/L) for 48 h and then exposed to 100 μmol/L H2O2 for 30 min. Viable cells were harvested, and dichloro-dihydro-fluorescein diacetate (DCFH-DA) was used to detect reactive oxygen species (ROS) level; cellular redox status and insulin secretion were measured; cell viability was determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay; mitochondrial membrane potential (MMP) was detected by flow cytometry; relative genes levels were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR); western blotting was used to determine protein expression of GSK-3β and p-GSK-3β (Ser9), and nuclear and cytoplasmic NRF2. Results H2O2 increased ROS production, and induced adverse affects in relation to antioxidant defense systems and insulin secretion. These changes were restored by treatment with 100 and 200 μmol/L GABA. In addition, 100 or 200 μmol/L GABA induced membrane depolarization and increased cell viability. These effects were mediated by Caspase-3, Bcl-2 associated X protein (Bax) and B-cell lymphoma-2 (Bcl-2) expression. Western blotting indicated that GABA inhibited GSK-3β by increasing p-GSK-3β (Ser9) level, and directed the transcription factor NRF2 to the nucleus. Conclusion In rat insulin-producing RINm5F cells, GABA exerts its protective effect by regulating GSK-3β and NRF2, which governs redox homeostasis by inhibiting apoptosis and abnormal insulin secretion by exposure to H2O2.
Collapse
Affiliation(s)
- Xue Tang
- 1State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122 Jiangsu China.,3School of Food Science and Technology, Jiangnan University, Wuxi, 214122 Jiangsu China
| | - Renqiang Yu
- 2The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002 Jiangsu China
| | - Qin Zhou
- 2The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002 Jiangsu China
| | - Shanyu Jiang
- 2The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University, Wuxi, 214002 Jiangsu China
| | - Guowei Le
- 1State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122 Jiangsu China.,3School of Food Science and Technology, Jiangnan University, Wuxi, 214122 Jiangsu China
| |
Collapse
|
29
|
Computational modeling of the effect of temperature variations on human pancreatic β-cell activity. J Therm Biol 2018; 75:69-80. [PMID: 30017054 DOI: 10.1016/j.jtherbio.2018.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 11/22/2022]
Abstract
The effect of temperature variations on the pancreatic β-cell activity and the role of different model compartments in temperature sensing have been investigated using a computational modeling approach. The results of our study show that temperature variations by several degrees can change the dynamical states of the β-cell system. In addition, temperature variations can alter the characteristic features of the membrane voltage, which correlates with insulin secretion. Simulation results show that the ion channels such as the L-type calcium, the hERG potassium, sodium channels and the glycolysis pathway are the possible sites for sensing temperature variation. Results indicate that for a small temperature change, even though the frequency and amplitude of electrical activity are altered, the area under the membrane potential curve remains almost unchanged, which implies the existence of a thermoregulatory mechanism for preserving the amount of insulin secretion. Furthermore, the computational analysis shows that the β-cell electrical activity exhibits a bursting pattern in physiological temperature (37 °C) while in vitro studies reported almost the spiking activity at lower temperatures. Since hormone-secreting systems work more efficient in bursting mode, we propose that the pancreatic β-cell works better in the physiological temperature compared with the reference temperature (33 °C).
Collapse
|
30
|
Januzi L, Poirier JW, Maksoud MJE, Xiang YY, Veldhuizen RAW, Gill SE, Cregan SP, Zhang H, Dekaban GA, Lu WY. Autocrine GABA signaling distinctively regulates phenotypic activation of mouse pulmonary macrophages. Cell Immunol 2018; 332:7-23. [PMID: 30017085 DOI: 10.1016/j.cellimm.2018.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 11/24/2022]
Abstract
In response to micro-environmental cues such as microbial infections or T-helper 1 and 2 (TH1 and TH2) cytokines, macrophages (Mϕs) develop into M1- or M2-like phenotypes. Phenotypic polarization/activation of Mϕs are also essentially regulated by autocrine signals. Type-A γ-aminobutyric acid receptor (GABAAR)-mediated autocrine signaling is critical for phenotypic differentiation and transformation of various cell types. The present study explored whether GABAAR signaling regulates lung Mϕ (LMϕ) phenotypic activation under M1/TH1 and M2/TH2 environments. Results showed that GABAAR subunits were expressed by primary LMϕ of mice and the mouse Mϕ cell line RAW264.7. The expression levels of GABAAR subunits in mouse LMϕs and RAW264.7 cells decreased or increased concurrently with classical (M1) or alternative (M2) activation, respectively. Moreover, activation or blockade of GABAARs distinctively influenced the phenotypic characteristics of Mϕ. These results suggested that microenvironments leading to LMϕ phenotypic polarization concurrently modulates autocrine GABA signaling and its role in Mϕ activation.
Collapse
Affiliation(s)
- Luan Januzi
- Department of Physiology and Pharmacology, University of Western Ontario, Canada
| | - Jacob W Poirier
- Department of Physiology and Pharmacology, University of Western Ontario, Canada.
| | | | - Yun-Yan Xiang
- Robarts Research Institute, University of Western Ontario, Canada.
| | | | - Sean E Gill
- Department of Physiology and Pharmacology, University of Western Ontario, Canada; Centre for Critical Illness Research, Lawson Health Research Institute, Canada.
| | - Sean P Cregan
- Department of Physiology and Pharmacology, University of Western Ontario, Canada; Robarts Research Institute, University of Western Ontario, Canada.
| | - Haibo Zhang
- Department of Anesthesia, University of Toronto, Canada.
| | | | - Wei-Yang Lu
- Department of Physiology and Pharmacology, University of Western Ontario, Canada; Graduate Program of Neuroscience, University of Western Ontario, Canada; Robarts Research Institute, University of Western Ontario, Canada; Department of Anesthesia, University of Toronto, Canada.
| |
Collapse
|
31
|
Chaiyasut C, Woraharn S, Sivamaruthi BS, Lailerd N, Kesika P, Peerajan S. Lactobacillus fermentum HP3-Mediated Fermented Hericium erinaceus Juice as a Health Promoting Food Supplement to Manage Diabetes Mellitus. J Evid Based Integr Med 2018; 23:2515690X18765699. [PMID: 29619846 PMCID: PMC5894895 DOI: 10.1177/2515690x18765699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The current study investigated the antidiabetic property of Lactobacillus fermentum HP3–mediated fermented Hericium erinaceus juice (FHJ) using male Wistar rats with streptozotocin-induced diabetes mellitus (DM). FHJ was prepared using boiled mushroom juice and L. fermentum HP3. Amino acid and γ-aminobutyric acid (GABA) content of FHJ was analyzed. Streptozotocin-induced DM rats were supplemented with FHJ in a pre- and posttreatment method. The changes in plasma insulin, plasma glucose level, glycated hemoglobin (HbA1c), representative cytokines, and the antioxidant system were assessed in experimental rats using spectrophotometric methods and enzyme-linked immunosorbent assay. The supplementation of FHJ improved the body mass, insulin level, and recovery progress of hyperglycemia. HbA1c level was altered by the FHJ intervention. The inflammatory cytokines level was suppressed in FHJ supplemented group compared with control. Intervention of FHJ and insulin improved the production of interleukin-10 and transforming growth factor-–β1 in DM rat. The study suggested that fermented H erinaceus juice may be used as one of the food-based health-promoting supplement to manage DM along with medication.
Collapse
Affiliation(s)
- Chaiyavat Chaiyasut
- 1 Innovation Center for Holistic Health, Nutraceuticals, and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand
| | - Sasimar Woraharn
- 1 Innovation Center for Holistic Health, Nutraceuticals, and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand.,2 Mahidol University Nakhon Sawan Campus, Nakhon Sawan, Thailand
| | - Bhagavathi Sundaram Sivamaruthi
- 1 Innovation Center for Holistic Health, Nutraceuticals, and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand
| | - Narissara Lailerd
- 3 Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Periyanaina Kesika
- 1 Innovation Center for Holistic Health, Nutraceuticals, and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand
| | | |
Collapse
|
32
|
Indrowati M, Pratiwi R, Rumiyati, Astuti P. Levels of Blood Glucose and Insulin Expression of Beta-cells in Streptozotocin-induced Diabetic Rats Treated with Ethanolic Extract of Artocarpus altilis Leaves and GABA. Pak J Biol Sci 2017; 20:28-35. [PMID: 29023012 DOI: 10.3923/pjbs.2017.28.35] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Information about the Artocarpus altilis leaf as an antidiabetic associated with the active compounds Gamma Amino Butyric Acid (GABA) is still limited. This study was conducted to determine the effects of ethanolic extract of A. altilis leaves decoction and GABA on blood glucose levels and insulin expression of beta-cells in streptozotocin-induced diabetic rats. MATERIAL AND METHODS This study was done by using completely randomized design and male Sprague Dewley rats. The rats were devided into normal control group and diabetic rats groups. Levels of bood glucose were measured using strip rapid test. The insulin expression in beta-cells was assessed using immunohistochemistry. Quantitative data were analyzed using ANOVA at 5% confidence level. RESULTS The result indicated that 50 mg k-1 b.wt., GABA, 400 and 800 mg k-1 b.wt., ethanolic extract of A. altilis leaves decreased the level of blood glucose and increased the insulin expression in pancreas beta-cells. CONCLUSION The GABA and ethanolic extract of A. altilis leaves with a minimum dose of 400 mg k-1 b.wt., can be used as an antidiabetic. Pancreas is the target organ was affected by GABA and A. altilis leaves as antidiabetic agents. Results of this study may support the development of research on the potency of GABA in natural materials as antidiabetic particularly type 1 diabetes.
Collapse
Affiliation(s)
- Meti Indrowati
- Department of Biological Education, Faculty of Teacher Training and Education, Universitas Sebelas Maret, Jalan Ir. Sutami 36A 57126, Surakarta, Indonesia
| | - Rarastoeti Pratiwi
- Faculty of Biology, Universitas Gadjah Mada, Jalan Te knika Selatan Sekip Utara, 55281 Yogyakarta, Indonesia
| | - Rumiyati
- Faculty of Pharmacy, Universitas Gadj ah Mada, 55281 Yogyakarta, Indonesia
| | - Pudji Astuti
- Faculty of Veterinary Medicine, Universitas Gadjah Mada, Jalan Fauna No. 2, Karangmalang, 55281 Yogyakarta, Indonesia
| |
Collapse
|
33
|
Abd El-Hady AM, Gewefel HS, Badawi MA, Eltahawy NA. Gamma-aminobutyric acid ameliorates gamma rays-induced oxidative stress in the small intestine of rats. THE JOURNAL OF BASIC AND APPLIED ZOOLOGY 2017; 78:2. [DOI: 10.1186/s41936-017-0005-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
34
|
Wang S, Sui S, Liu Z, Peng C, Liu J, Luo D, Fan X, Liu C, Lu WY. Protective roles of hepatic gamma-aminobutyric acid signaling in acute ethanol exposure-induced liver injury. J Appl Toxicol 2017; 38:341-350. [PMID: 29044621 DOI: 10.1002/jat.3544] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 09/03/2017] [Accepted: 09/04/2017] [Indexed: 11/06/2022]
Abstract
Alcoholic liver disease (ALD) is a consequence of heavy and prolonged alcohol consumptions. We previously demonstrated a hepatic gamma-aminobutyric acid (GABA) signaling system that protects the liver from toxic injury. The present study was designed to investigate the role of the hepatic GABA signaling system in the process of acute ethanol exposure-induced liver injury. Our results showed that the expression of GABA synthesizing enzyme glutamic acid decarboxylase and type A GABA receptor (GABAA R) subunits was upregulated in ethanol-treated mice compared with saline-treated controls. Remarkably, pretreatment of mice with GABA (1.5 mg kg-1 body weight, intraperitoneal injection [i.p.]) or with the GABAA R agonist muscimol (1.2 mg kg-1 body weight, i.p.) protected the liver against ethanol toxicity and improved liver function, whereas pretreatment of mice with the GABAA R antagonist bicuculline (2.0 mg kg-1 body weight, i.p.) worsened the liver function. Further analyses suggest that GABAA R-mediated signaling protects the liver from ethanol injury by, at least partially, inhibiting the IRE1α-ASK1-JNK pro-apoptotic pathway in hepatocytes in the process of ethanol-induced endoplasmic reticulum stress response.
Collapse
Affiliation(s)
- Shuanglian Wang
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Shaofeng Sui
- Shandong Center for Disease Control and Prevention, Institute of Occupational and Environmental Health, Jinan, Shandong, People's Republic of China
| | - Zhiyan Liu
- Department of Pathology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Cheng Peng
- Shandong University Qi Lu Hospital, Jinan, Shandong, People's Republic of China
| | - Jia Liu
- Xinhua Hospital, Huainan, Anhui, People's Republic of China
| | - Dan Luo
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Xinhuan Fan
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Chuanyong Liu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.,Robarts Research Institute, University of Western Ontario, London, ON, Canada
| |
Collapse
|
35
|
Feng AL, Xiang YY, Gui L, Kaltsidis G, Feng Q, Lu WY. Paracrine GABA and insulin regulate pancreatic alpha cell proliferation in a mouse model of type 1 diabetes. Diabetologia 2017; 60:1033-1042. [PMID: 28280900 DOI: 10.1007/s00125-017-4239-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/08/2017] [Indexed: 01/20/2023]
Abstract
AIMS/HYPOTHESIS This study aimed to elucidate the mechanism of increased proliferation of alpha cells in recent-onset type 1 diabetes. Pancreatic beta cells express GAD and produce γ-aminobutyric acid (GABA), which inhibits alpha cell secretion of glucagon. We explored the roles of GABA in alpha cell proliferation in conditions corresponding to type 1 diabetes in a mouse model and in vitro. METHODS Type 1 diabetes was induced by injecting the mice with streptozotocin (STZ). Some of the STZ-injected mice were treated with GABA (10 mg/kg daily) for 12 days. Isolated pancreatic islets were treated with STZ or STZ together with GABA for 2 days. The effects of GABA treatment on STZ-induced alpha cell proliferation in vivo and in vitro were assessed. The effect of muscimol, a GABA receptor agonist, on αTC1-6 cell proliferation was also examined. RESULTS STZ injection substantially decreased levels of GAD, GABA and insulin in pancreatic beta cells 12 h after injection; this was followed by an upsurge of phosphorylated mechanistic target of rapamycin (p-mTOR) in the alpha cells at day 1, and a significant increase in alpha cell mass at day 3. Treating STZ-injected mice with GABA largely restored the immunodetectable levels of insulin and GAD in the beta cells and significantly decreased the number of aldehyde dehydrogenase 1 family, member A3 (ALDH1a3)-positive cells, alpha cell mass and hyperglucagonaemia. STZ treatment also increased alpha cell proliferation in isolated islets, which was reversed by co-treatment with GABA. Muscimol, together with insulin, significantly lowered the level of cytosolic Ca2+ and p-mTOR, and decreased the proliferation rate of αTC1-6 cells. CONCLUSIONS/INTERPRETATION GABA signalling critically controls the alpha cell population in pancreatic islets. Low intraislet GABA may contribute to alpha cell hyperplasia in early type 1 diabetes.
Collapse
Affiliation(s)
- Allen L Feng
- Robarts Research Institute, Rome: 7240, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Yun-Yan Xiang
- Robarts Research Institute, Rome: 7240, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada
| | - Le Gui
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Gesthika Kaltsidis
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Qingping Feng
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Wei-Yang Lu
- Robarts Research Institute, Rome: 7240, University of Western Ontario, 1151 Richmond Street North, London, ON, N6A 5B7, Canada.
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
| |
Collapse
|
36
|
Wang S, Xiang YY, Zhu J, Yi F, Li J, Liu C, Lu WY. Protective roles of hepatic GABA signaling in acute liver injury of rats. Am J Physiol Gastrointest Liver Physiol 2017; 312:G208-G218. [PMID: 27979827 DOI: 10.1152/ajpgi.00344.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/05/2016] [Accepted: 12/12/2016] [Indexed: 01/31/2023]
Abstract
γ-Aminobutyric acid (GABA) is produced by various cells through the catalytic activity of glutamic acid decarboxylase (GAD). Activation of type-A GABA receptor (GABAAR) inhibits stem cell proliferation but protects differentiated cells from injures. The present study investigated hepatic GABA signaling system and the role of this system in liver physiology and pathophysiology. RT-PCR and immunoblot assays identified GAD and GABAAR subunits in rat livers and in HepG2 and Clone 9 hepatocytes. Patch-clamp recording detected GABA-induced currents in Clone 9 hepatocytes and depolarization in WITT cholangiocytes. The function of hepatic GABA signaling system in rats was examined using models of d-galactosamine (GalN)-induced acute hepatocytic injury in vivo and in vitro. The expression of GAD increased whereas GABAAR subunits decreased in the liver of GalN-treated rats. Remarkably, treating rats with GABA or the GABAAR agonist muscimol, but not the GABABR agonist baclofen, protected hepatocytes against GalN toxicity and improved liver function. In addition, muscimol treatment decreased the formation of pseudobile ductules and the enlargement of hepatocytic canaliculi in GalN-treated rats. Our results revealed that a complex GABA signaling system exists in the rat liver. Activation of this intrahepatic GABAergic system protected the liver against toxic injury.NEW & NOTEWORTHY Auto- and paracrine GABAergic signaling systems exist in the rat hepatocytes and cholangiocytes. Activation of GABA signaling protects liver function from d-galactosamine injury by reducing toxic impairment of hepatocytes and by decreasing cholangiocyte proliferation.
Collapse
Affiliation(s)
- Shuanglian Wang
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China.,Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada; and
| | - Yun-Yan Xiang
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada; and
| | - Jianchun Zhu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Fan Yi
- Department of Pharmacology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China
| | - Jingxin Li
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada; and
| | - Chuanyong Liu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, People's Republic of China;
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; .,Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada; and
| |
Collapse
|
37
|
Tsuneki H, Sasaoka T, Sakurai T. Sleep Control, GPCRs, and Glucose Metabolism. Trends Endocrinol Metab 2016; 27:633-642. [PMID: 27461005 DOI: 10.1016/j.tem.2016.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/29/2016] [Accepted: 06/29/2016] [Indexed: 12/29/2022]
Abstract
Modern lifestyles prolong daily activities into the nighttime, disrupting circadian rhythms, which may cause sleep disturbances. Sleep disturbances have been implicated in the dysregulation of blood glucose levels and reported to increase the risk of type 2 diabetes (T2D) and diabetic complications. Sleep disorders are treated using anti-insomnia drugs that target ionotropic and G protein-coupled receptors (GPCRs), including γ-aminobutyric acid (GABA) agonists, melatonin agonists, and orexin receptor antagonists. A deeper understanding of the effects of these medications on glucose metabolism and their underlying mechanisms of action is crucial for the treatment of diabetic patients with sleep disorders. In this review we focus on the beneficial impact of sleep on glucose metabolism and suggest a possible strategy for therapeutic intervention against sleep-related metabolic disorders.
Collapse
Affiliation(s)
- Hiroshi Tsuneki
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| | - Takeshi Sakurai
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.
| |
Collapse
|
38
|
Li Q, Gu W, Ma X, Liu Y, Jiang L, Feng R, Liu L. Amino Acid and Biogenic Amine Profile Deviations in an Oral Glucose Tolerance Test: A Comparison between Healthy and Hyperlipidaemia Individuals Based on Targeted Metabolomics. Nutrients 2016; 8:nu8060379. [PMID: 27338465 PMCID: PMC4924220 DOI: 10.3390/nu8060379] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/12/2016] [Accepted: 06/16/2016] [Indexed: 12/22/2022] Open
Abstract
Hyperlipidemia (HLP) is characterized by a disturbance in lipid metabolism and is a primary risk factor for the development of insulin resistance (IR) and a well-established risk factor for cardiovascular disease and atherosclerosis. The aim of this work was to investigate the changes in postprandial amino acid and biogenic amine profiles provoked by an oral glucose tolerance test (OGTT) in HLP patients using targeted metabolomics. We used ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry to analyze the serum amino acid and biogenic amine profiles of 35 control and 35 HLP subjects during an OGTT. The amino acid and biogenic amine profiles from 30 HLP subjects were detected as independent samples to validate the changes in the metabolites. There were differences in the amino acid and biogenic amine profiles between the HLP individuals and the healthy controls at baseline and after the OGTT. The per cent changes of 13 metabolites from fasting to the 2 h samples during the OGTT in the HLP patients were significantly different from those of the healthy controls. The lipid parameters were associated with the changes in valine, isoleucine, creatine, creatinine, dimethylglycine, asparagine, serine, and tyrosine (all p < 0.05) during the OGTT in the HLP group. The postprandial changes in isoleucine and γ-aminobutyric acid (GABA) during the OGTT were positively associated with the homeostasis model assessment of insulin resistance (HOMA-IR; all p < 0.05) in the HLP group. Elevated oxidative stress and disordered energy metabolism during OGTTs are important characteristics of metabolic perturbations in HLP. Our findings offer new insights into the complex physiological regulation of metabolism during the OGTT in HLP.
Collapse
Affiliation(s)
- Qi Li
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Wenbo Gu
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Xuan Ma
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Yuxin Liu
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Lidan Jiang
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Rennan Feng
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| | - Liyan Liu
- Department of Nutrition and Food Hygiene, National Key Discipline, Public Health College, Harbin Medical University, Harbin 150086, China.
| |
Collapse
|
39
|
Marques TM, Patterson E, Wall R, O'Sullivan O, Fitzgerald GF, Cotter PD, Dinan TG, Cryan JF, Ross RP, Stanton C. Influence of GABA and GABA-producing Lactobacillus brevis DPC 6108 on the development of diabetes in a streptozotocin rat model. Benef Microbes 2016; 7:409-20. [PMID: 27013462 DOI: 10.3920/bm2015.0154] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The aim of this study was to investigate if dietary administration of γ-aminobutyric acid (GABA)-producing Lactobacillus brevis DPC 6108 and pure GABA exert protective effects against the development of diabetes in streptozotocin (STZ)-induced diabetic Sprague Dawley rats. In a first experiment, healthy rats were divided in 3 groups (n=10/group) receiving placebo, 2.6 mg/kg body weight (bw) pure GABA or L. brevis DPC 6108 (~10(9)microorganisms). In a second experiment, rats (n=15/group) were randomised to five groups and four of these received an injection of STZ to induce type 1 diabetes. Diabetic and non-diabetic controls received placebo [4% (w/v) yeast extract in dH2O], while the other three diabetic groups received one of the following dietary supplements: 2.6 mg/kg bw GABA (low GABA), 200 mg/kg bw GABA (high GABA) or ~10(9) L. brevis DPC 6108. L. brevis DPC 6108 supplementation was associated with increased serum insulin levels (P<0.05), but did not alter other metabolic markers in healthy rats. Diabetes induced by STZ injection decreased body weight (P<0.05), increased intestinal length (P<0.05) and stimulated water and food intake. Insulin was decreased (P<0.05), whereas glucose was increased (P<0.001) in all diabetic groups, compared with non-diabetic controls. A decrease (P<0.01) in glucose levels was observed in diabetic rats receiving L. brevis DPC 6108, compared with diabetic-controls. Both the composition and diversity of the intestinal microbiota were affected by diabetes. Microbial diversity in diabetic rats supplemented with low GABA was not reduced (P>0.05), compared with non-diabetic controls while all other diabetic groups displayed reduced diversity (P<0.05). L. brevis DPC 6108 attenuated hyperglycaemia induced by diabetes but additional studies are needed to understand the mechanisms involved in this reduction.
Collapse
Affiliation(s)
- T M Marques
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland.,3 School of Microbiology, University College Cork, Cork, Ireland
| | - E Patterson
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland.,3 School of Microbiology, University College Cork, Cork, Ireland
| | - R Wall
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - O O'Sullivan
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - G F Fitzgerald
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,3 School of Microbiology, University College Cork, Cork, Ireland
| | - P D Cotter
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - T G Dinan
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,4 Department of Psychiatry and Neurobehavioural Science, Biosciences Institute, University College Cork, Cork, Ireland
| | - J F Cryan
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland
| | - R P Ross
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland
| | - C Stanton
- 1 APC Microbiome Institute, University College Cork, Cork, Ireland.,2 Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| |
Collapse
|
40
|
Li J, Zhang Z, Liu X, Wang Y, Mao F, Mao J, Lu X, Jiang D, Wan Y, Lv JY, Cao G, Zhang J, Zhao N, Atkinson M, Greiner DL, Prud'homme GJ, Jiao Z, Li Y, Wang Q. Study of GABA in Healthy Volunteers: Pharmacokinetics and Pharmacodynamics. Front Pharmacol 2015; 6:260. [PMID: 26617516 PMCID: PMC4639630 DOI: 10.3389/fphar.2015.00260] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/20/2015] [Indexed: 01/13/2023] Open
Abstract
Preclinical studies show that GABA exerts anti-diabetic effects in rodent models of type 1 diabetes. Because little is known about its absorption and effects in humans, we investigated the pharmacokinetics and pharmacodynamics of GABA in healthy volunteers. Twelve subjects were subjected to an open-labeled, three-period trial involving sequential oral administration of placebo, 2 g GABA once, and 2 g GABA three times/day for 7 days, with a 7-day washout between each period. GABA was rapidly absorbed (Tmax: 0.5 ~ 1 h) with the half-life (t1/2) of 5 h. No accumulation was observed after repeated oral GABA administration for 7 days. Remarkably, GABA significantly increased circulating insulin levels in the subjects under either fasting (1.6-fold, single dose; 2.0-fold, repeated dose; p < 0.01) or fed conditions (1.4-fold, single dose; 1.6-fold, repeated dose; p < 0.01). GABA also increased glucagon levels only under fasting conditions (1.3-fold, single dose, p < 0.05; 1.5-fold, repeated dose, p < 0.01). However, there were no significant differences in the insulin-to-glucagon ratio and no significant change in glucose levels in these healthy subjects during the study period. Importantly, GABA significantly decreased glycated albumin levels in the repeated dosing period. Subjects with repeated dosing showed an elevated incidence of minor adverse events in comparison to placebo or the single dosing period, most notably transient discomforts such as dizziness and sore throat. However, there were no serious adverse events observed throughout the study. Our data show that GABA is rapidly absorbed and tolerated in human beings; its endocrine effects, exemplified by increasing islet hormonal secretion, suggest potential therapeutic benefits for diabetes.
Collapse
Affiliation(s)
- Junfeng Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Zhaoyun Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Xiaoxia Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Yi Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Fei Mao
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Junjun Mao
- Department of Pharmacy, Huashan Hospital, Fudan University Shanghai, China
| | - Xiaolan Lu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Dongdong Jiang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Yun Wan
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Jia-Ying Lv
- Department of Biostatistics, School of Public Health, Fudan University Shanghai, China
| | - Guoying Cao
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Institute of Antibiotics, Huashan Hospital, Fudan University Shanghai, China
| | - Jing Zhang
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Institute of Antibiotics, Huashan Hospital, Fudan University Shanghai, China
| | - Naiqing Zhao
- Department of Biostatistics, School of Public Health, Fudan University Shanghai, China
| | - Mark Atkinson
- Department of Pathology, College of Medicine, University of Florida Gainesville, FL, USA
| | - Dale L Greiner
- Department of Molecular Medicine, University of Massachusetts Medical School Worcester, MA, USA
| | - Gerald J Prud'homme
- Department of Laboratory Medicine and Pathobiology, Keenan Research Centre for Biomedical Science of St. Michael's Hospital, University of Toronto Toronto, ON, Canada
| | - Zheng Jiao
- Department of Pharmacy, Huashan Hospital, Fudan University Shanghai, China
| | - Yiming Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University Shanghai, China ; Division of Endocrinology and Metabolism, The Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital Toronto, ON, Canada ; Department of Physiology and Medicine, University of Toronto ON, Canada
| |
Collapse
|
41
|
Boulan L, Milán M, Léopold P. The Systemic Control of Growth. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a019117. [PMID: 26261282 DOI: 10.1101/cshperspect.a019117] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Growth is a complex process that is intimately linked to the developmental program to form adults with proper size and proportions. Genetics is an important determinant of growth, as exemplified by the role of local diffusible molecules setting up organ proportions. In addition, organisms use adaptive responses allowing modulating the size of individuals according to environmental cues, for example, nutrition. Here, we describe some of the physiological principles participating in the determination of final individual size.
Collapse
Affiliation(s)
- Laura Boulan
- University of Nice-Sophia Antipolis, 06108 Nice, France CNRS, University of Nice-Sophia Antipolis, 06108 Nice, France INSERM, University of Nice-Sophia Antipolis, 06108 Nice, France
| | - Marco Milán
- 5ICREA, Parc Cientific de Barcelona, 08028 Barcelona, Spain
| | - Pierre Léopold
- University of Nice-Sophia Antipolis, 06108 Nice, France CNRS, University of Nice-Sophia Antipolis, 06108 Nice, France INSERM, University of Nice-Sophia Antipolis, 06108 Nice, France
| |
Collapse
|
42
|
Postprandial Differences in the Amino Acid and Biogenic Amines Profiles of Impaired Fasting Glucose Individuals after Intake of Highland Barley. Nutrients 2015; 7:5556-71. [PMID: 26184292 PMCID: PMC4517015 DOI: 10.3390/nu7075238] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 06/15/2015] [Accepted: 07/01/2015] [Indexed: 12/26/2022] Open
Abstract
The aim of this study was to measure the postprandial changes in amino acid and biogenic amine profiles in individuals with impaired fasting glucose (IFG) and to investigate the changes of postprandial amino acid and biogenic amine profiles after a meal of highland barley (HB). Firstly, 50 IFG and 50 healthy individuals were recruited for the measurement of 2 h postprandial changes of amino acid and biogenic amine profiles after a glucose load. Secondly, IFG individuals received three different loads: Glucose (GL), white rice (WR) and HB. Amino acid and biogenic amine profiles, glucose and insulin were assayed at time zero and 30, 60, 90 and 120 min after the test load. The results showed fasting and postprandial amino acid and biogenic amine profiles were different between the IFG group and the controls. The level of most amino acids and their metabolites decreased after an oral glucose tolerance test, while the postprandial level of γ-aminobutyric acid (GABA) increased significantly in IFG individuals. After three different test loads, the area under the curve for glucose, insulin, lysine and GABA after a HB load decreased significantly compared to GL and WR loads. Furthermore, the postprandial changes in the level of GABA between time zero and 120 min during a HB load were associated positively with 2 h glucose and fasting insulin secretion in the IFG individuals. Thus, the HB load produced low postprandial glucose and insulin responses, which induced changes in amino acid and biogenic amine profiles and improved insulin sensitivity.
Collapse
|
43
|
Wan Y, Wang Q, Prud’homme GJ. GABAergic system in the endocrine pancreas: a new target for diabetes treatment. Diabetes Metab Syndr Obes 2015; 8:79-87. [PMID: 25678807 PMCID: PMC4322886 DOI: 10.2147/dmso.s50642] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Excessive loss of functional pancreatic β-cell mass, mainly due to apoptosis, is a major factor in the development of hyperglycemia in both type 1 and type 2 diabetes (T1D and T2D). In T1D, β-cells are destroyed by immunological mechanisms. In T2D, while metabolic factors are known to contribute to β-cell failure and subsequent apoptosis, mounting evidence suggests that islet inflammation also plays an important role in the loss of β-cell mass. Therefore, it is of great importance for clinical intervention to develop new therapies. γ-Aminobutyric acid (GABA), a major neurotransmitter, is also produced by islet β-cells, where it functions as an important intraislet transmitter in regulating islet-cell secretion and function. Importantly, recent studies performed in rodents, including in vivo studies of xenotransplanted human islets, reveal that GABA exerts β-cell regenerative effects. Moreover, it protects β-cells against apoptosis induced by cytokines, drugs, and other stresses, and has anti-inflammatory and immunoregulatory activities. It ameliorates the manifestations of diabetes in preclinical models, suggesting potential applications for the treatment of diabetic patients. This review outlines the actions of GABA relevant to β-cell regeneration, including its signaling mechanisms and potential interactions with other mediators. These studies increase our understanding of the regenerative processes of pancreatic β-cells, and help pave the way for the development of regenerative medicine for diabetes.
Collapse
Affiliation(s)
- Yun Wan
- Department of Endocrinology and Metabolism, Huashan Hospital, Medical College, Fudan University, Shanghai, People’s Republic of China
| | - Qinghua Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Medical College, Fudan University, Shanghai, People’s Republic of China
- Division of Endocrinology and Metabolism, Keenan Research Centre for Biomedical Science of St Michael’s Hospital, Toronto, ON, Canada
- Departments of Physiology and Medicine, Faculty of Medicine, Toronto, ON, Canada
- Correspondence: Qinghua Wang, Division of Endocrinology and Metabolism, St Michael’s Hospital, 30 Bond Street, Toronto, ON M5B 1W8, Canada, Tel +1 416 864 6060 ext 77 610, Fax +1 416 864 5140, Email
| | - Gerald J Prud’homme
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine, Keenan Research Centre for Biomedical Science, St Michael’s Hospital, Toronto, ON, Canada
| |
Collapse
|
44
|
Wang S, Luo Y, Feng A, Li T, Yang X, Nofech-Mozes R, Yu M, Wang C, Li Z, Yi F, Liu C, Lu WY. Ethanol induced impairment of glucose metabolism involves alterations of GABAergic signaling in pancreatic β-cells. Toxicology 2014; 326:44-52. [PMID: 25456265 DOI: 10.1016/j.tox.2014.10.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 01/02/2023]
Abstract
Alcohol overindulgence is a risk factor of type 2 diabetes mellitus. However, the mechanisms by which alcohol overindulgence damages glucose metabolism remain unclear. Pancreatic islet β-cells are endowed with type-A γ-aminobutyric acid receptor (GABAAR) mediated autocrine signaling mechanism, which regulates insulin secretion and fine-tunes glucose metabolism. In neurons GABAAR is one of the major targets for alcohol. This study investigated whether ethanol alters glucose metabolism by affecting GABAAR signaling in pancreatic β-cells. Blood glucose level of test mice was measured using a blood glucose meter. Insulin secretion by the pancreatic β-cell line INS-1 cells was examined using a specific insulin ELISA kit. Whole-cell patch-clamp recording was used to evaluate GABA-elicited current in INS-1 cells. Western blot and immunostaining were used to measure the expression of GABAAR subunits in mouse pancreatic tissues or in INS-1 cells. Intraperitoneal (i.p.) administration of ethanol (3.0g/kg body weight) to mice altered glucose metabolism, which was associated with decreased expression of GABAAR α1- and δ- subunits on the surface of pancreatic β-cells. Acute treatment of cultured INS-1cells with ethanol (60mM) decreased the GABA-induced current and reduced insulin secretion. In contrast, treating INS-1 cells with GABA (100μM) largely prevented the ethanol-induced reduction of insulin release. Importantly, pre-treating mice with GABA (i.p., 1.5mg/kg body weight) partially reversed ethanol-induced impairment of glucose homeostasis in mice. Our data suggest a novel role of pancreatic GABA signaling in protecting pancreatic islet β-cells from ethanol-induced dysfunction.
Collapse
Affiliation(s)
- Shuanglian Wang
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Yan Luo
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Allen Feng
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada; Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Tao Li
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Xupeng Yang
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Roy Nofech-Mozes
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada; Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Meng Yu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Changhui Wang
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Ziwei Li
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Fan Yi
- Department of Pharmacology, Shandong University School of Medicine, Jinan, Shandong, PR China
| | - Chuanyong Liu
- Department of Physiology, Shandong University School of Medicine, Jinan, Shandong, PR China.
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada; Robarts Research Institute, University of Western Ontario, London, ON, Canada.
| |
Collapse
|
45
|
Williams DB. Inhibitory effects of insulin on GABAAcurrents modulated by the GABAAalpha subunit. J Recept Signal Transduct Res 2014; 35:516-22. [DOI: 10.3109/10799893.2014.960935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
46
|
Insight into insulin secretion from transcriptome and genetic analysis of insulin-producing cells of Drosophila. Genetics 2014; 197:175-92. [PMID: 24558258 PMCID: PMC4012477 DOI: 10.1534/genetics.113.160663] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Insulin-producing cells (IPCs) in the Drosophila brain produce and release insulin-like peptides (ILPs) to the hemolymph. ILPs are crucial for growth and regulation of metabolic activity in flies, functions analogous to those of mammalian insulin and insulin-like growth factors (IGFs). To identify components functioning in IPCs to control ILP production, we employed genomic and candidate gene approaches. We used laser microdissection and messenger RNA sequencing to characterize the transcriptome of larval IPCs. IPCs highly express many genes homologous to genes active in insulin-producing β-cells of the mammalian pancreas. The genes in common encode ILPs and proteins that control insulin metabolism, storage, secretion, β-cell proliferation, and some not previously linked to insulin production or β-cell function. Among these novelties is unc-104, a kinesin 3 family gene, which is more highly expressed in IPCs compared to most other neurons. Knockdown of unc-104 in IPCs impaired ILP secretion and reduced peripheral insulin signaling. Unc-104 appears to transport ILPs along axons. As a complementary approach, we tested dominant-negative Rab genes to find Rab proteins required in IPCs for ILP production or secretion. Rab1 was identified as crucial for ILP trafficking in IPCs. Inhibition of Rab1 in IPCs increased circulating sugar levels, delayed development, and lowered weight and body size. Immunofluorescence labeling of Rab1 showed its tight association with ILP2 in the Golgi of IPCs. Unc-104 and Rab1 join other proteins required for ILP transport in IPCs.
Collapse
|
47
|
Analysis of synaptic-like microvesicle exocytosis of B-cells using a live imaging technique. PLoS One 2014; 9:e87758. [PMID: 24503905 PMCID: PMC3913683 DOI: 10.1371/journal.pone.0087758] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 01/02/2014] [Indexed: 11/19/2022] Open
Abstract
Pancreatic β-cells play central roles in blood glucose homeostasis. Beside insulin, these cells release neurotransmitters and other signaling molecules stored in synaptic-like microvesicles (SLMVs). We monitored SLMV exocytosis by transfecting a synaptophysin-pHluorin construct and by visualizing the cells by Total Internal Reflection Fluorescence (TIRF) microscopy. SLMV fusion was elicited by 20 mM glucose and by depolarizing K+ concentrations with kinetics comparable to insulin secretion. SLMV exocytosis was prevented by Tetanus and Botulinum-C neurotoxins indicating that the fusion machinery of these organelles includes VAMP-2/-3 and Syntaxin-1, respectively. Sequential visualization of SLMVs by TIRF and epifluorescence microscopy showed that after fusion the vesicle components are rapidly internalized and the organelles re-acidified. Analysis of single fusion episodes revealed the existence of two categories of events. While under basal conditions transient fusion events prevailed, long-lasting episodes were more frequent upon secretagogue exposure. Our observations unveiled similarities between the mechanism of exocytosis of insulin granules and SLMVs. Thus, diabetic conditions characterized by defective insulin secretion are most probably associated also with inappropriate release of molecules stored in SLMVs. The assessment of the contribution of SLMV exocytosis to the manifestation of the disease will be facilitated by the use of the imaging approach described in this study.
Collapse
|
48
|
Gramaglia E, Ramella Gigliardi V, Olivetti I, Tomelini M, Belcastro S, Calvi E, Dotta A, Ghigo E, Benso A, Broglio F. Impact of short-term treatment with benzodiazepines and imidazopyridines on glucose metabolism in healthy subjects. J Endocrinol Invest 2014; 37:203-6. [PMID: 24497220 DOI: 10.1007/s40618-013-0016-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 11/16/2013] [Indexed: 11/29/2022]
Abstract
AIM In the last years there has been a progressive reduction of the average duration of sleep and an increase in the incidence of sleep disturbances. At the same time, an increase of the incidence of the metabolic syndrome has been described, partly attributable to the progressive worsening of dietary habits and the increase in sedentary lifestyle. Recent studies suggest that adequate sleep is essential to maintain good glucose metabolism and sleep disturbances may contribute to the manifestation of the metabolic syndrome. Benzodiazepines (BZ), such as brotizolam, and imidazopyridines, such as zolpidem, are frequently used as hypnotics but their potential impact on glucose metabolism has never been evaluated so far. METHODS In 12 healthy volunteers [age (mean ± SEM) 38.3 ± 8.1 years; body mass index (BMI) 21.9 ± 0.8 kg/m²] we studied glucose and insulin responses to oral glucose tolerance test (OGTT, 75 g) before and after 15 days treatment with brotizolam 0.25 mg/day or zolpidem 10 mg/day. RESULTS Brotizolam increased glucose delta area under curve response to the OGTT by 122 % (p < 0.01) and zolpidem by 86 % (p < 0.01) without significant variations of insulin levels, suggesting an impact on insulin sensitivity and/or insulin secretion. CONCLUSIONS This study suggests that BZ and imidazopyridines have a rapid glucometabolic effect that is detectable as early as after 15 days treatment.
Collapse
Affiliation(s)
- E Gramaglia
- Division of Endocrinology, Diabetology and Metabolism, Department of Internal Medicine, A.O. Città Della Salute e Della Scienza, San Giovanni Battista, Molinette Hospital, University of Turin, Corso Dogliotti, 14, 10126, Turin, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Cherng SH, Huang CY, Kuo WW, Lai SE, Tseng CY, Lin YM, Tsai FJ, Wang HF. GABA tea prevents cardiac fibrosis by attenuating TNF-alpha and Fas/FasL-mediated apoptosis in streptozotocin-induced diabetic rats. Food Chem Toxicol 2013; 65:90-6. [PMID: 24374093 DOI: 10.1016/j.fct.2013.12.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 11/18/2013] [Accepted: 12/18/2013] [Indexed: 12/28/2022]
Abstract
GABA tea is a tea product that contains a high level of gamma-aminobutyric acid (GABA). This study investigated the effects of GABA tea on the heart in a diabetic rat model. Male Wistar rats were injected with 55mg/kg streptozotocin (STZ) to induce diabetes for 2weeks and then orally given dosages of 4.55 and 45.5mg/kg/day GABA tea extract for 6weeks. The results revealed that fasting blood glucose levels returned to normal levels in GABA tea-treated diabetic rats, but not in the untreated diabetic rats. Additionally, GABA tea effectively inhibited cardiac fibrosis induced by STZ. Further experiments showed that the STZ-induced protein levels of tumor necrosis factor-alpha (TNF-alpha), Fas, activated caspase-8 and caspase-3 were significantly inhibited by the GABA tea treatment. Therefore, our data suggest that the inhibiting effect of GABA tea on STZ-induced cardiac fibrosis in diabetic rats may be mediated by reducing blood glucose and further attenuating TNF-alpha expression and/or Fas/Fas ligand (FasL)-mediated apoptosis. These findings will provide implications for the potential anti-diabetic properties of GABA tea.
Collapse
Affiliation(s)
- Shur-Hueih Cherng
- Department of Biotecnology, Hungkuang University, Taichung 43302, Taiwan
| | - Chih-Yang Huang
- Graduate Institute of Chinese Medical Science, China Medical University, Taichung 40402, Taiwan; Graduate Institute of Basic Medical Science, China Medical University, Taichung 40402, Taiwan; Department of Biotechnology, Asia University, Taichung 41354, Taiwan
| | - Wei-Wen Kuo
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan
| | - Shue-Er Lai
- Department of Nutrition, Graduate Programs of Biomedical Nutrition, Hungkuang University, Taichung 43302, Taiwan; Department of Nutrition, Chung-Kang Branch, Cheng Ching Hospital, Taichung 40764, Taiwan
| | - Chien-Yu Tseng
- Department of Nutrition, Graduate Programs of Biomedical Nutrition, Hungkuang University, Taichung 43302, Taiwan
| | - Yueh-Min Lin
- Department of Pathology, Changhua Christian Hospital, Changhua 50094, Taiwan; Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 35664, Taiwan, Republic of China
| | - Fuu-Jen Tsai
- Graduate Institute of Chinese Medical Science, China Medical University, Taichung 40402, Taiwan
| | - Hsueh-Fang Wang
- Department of Nutrition, Graduate Programs of Biomedical Nutrition, Hungkuang University, Taichung 43302, Taiwan.
| |
Collapse
|
50
|
GABA protects human islet cells against the deleterious effects of immunosuppressive drugs and exerts immunoinhibitory effects alone. Transplantation 2013; 96:616-23. [PMID: 23851932 DOI: 10.1097/tp.0b013e31829c24be] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND We recently found that γ-aminobutyric acid (GABA) protects mouse islet β cells. It prevented autoimmune type 1 diabetes in mice, induced islet β-cell regeneration, and exerted immunoinhibitory effects. However, it is not known whether GABA would be equally active on human islet and immune cells. METHODS In vitro culture of human islets and immune cells with or without GABA and immunosuppressive drugs. In vitro analysis of apoptosis, proliferation, nuclear factor (NF)-κB activation, calcium signaling, and insulin secretion. RESULTS GABA reduced human islet cell apoptosis in culture, such that the yield of live cells was approximately tripled after 1 week, and it stimulated insulin secretion. It protected against the deleterious effects of rapamycin, tacrolimus, and mycophenolate mofetil. In human immune cells, GABA had inhibitory effects similar to mouse cells, such as suppressed anti-CD3-stimulated T-cell proliferation, in a GABA type A receptor-dependent fashion. The immunosuppressive mechanisms have been unclear, but we found that GABA blocked calcium influx, which is a key activation signal. GABA also suppressed NF-κB activation in both human islet cells and immune cells. We found that it could be combined with rapamycin to increase its suppressive effects. CONCLUSIONS GABA improved human islet cell survival and had suppressive effects on human immune cells. It inhibited canonical NF-κB activation in both islet and immune cells. This is important because activation of this pathway is detrimental to islet cells and likely promotes damaging autoimmunity and alloreactivity against transplanted islets. These findings suggest that GABA might find applications in clinical islet transplantation.
Collapse
|