1
|
Fang Y, Feng H, Zhang B, Zhang S, Zhou Y, Hao P, Zhou Z, Zhou S, Li N, Hui Y, Ma L, Xiong J, Wu J, Liu L, Zhang X. Cytosolic pH is a direct nexus in linking environmental cues with insulin processing and secretion in pancreatic β cells. Cell Metab 2024:S1550-4131(24)00059-7. [PMID: 38513648 DOI: 10.1016/j.cmet.2024.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/01/2023] [Accepted: 02/22/2024] [Indexed: 03/23/2024]
Abstract
Pancreatic β cells actively respond to glucose fluctuations through regulating insulin processing and secretion. However, how this process is elaborately tuned in circumstance of variable microenvironments as well as β cell-intrinsic states and whether its dysfunction links to metabolic diseases remain largely elusive. Here, we show that the cytosolic pH (pHc) in β cells is increased upon glucose challenge, which can be sensed by Smad5 via its nucleocytoplasmic shuttling. Lesion of Smad5 in β cells results in hyperglycemia and glucose intolerance due to insulin processing and secretion deficiency. The role of Smad5 in regulating insulin processing and secretion attributes to its non-canonical function by regulating V-ATPase activity for granule acidification. Genetic mutation of Smad5 or administration of alkaline water to mirror cytosolic alkalization ameliorated glucose intolerance in high-fat diet (HFD)-treated mice. Collectively, our findings suggest that pHc is a direct nexus in linking environmental cues with insulin processing and secretion in β cells.
Collapse
Affiliation(s)
- Yujiang Fang
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China.
| | - Hexi Feng
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Bowen Zhang
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Shuwei Zhang
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Yanjie Zhou
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Pengcheng Hao
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Zhongshu Zhou
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Shanshan Zhou
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Nan Li
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Yi Hui
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Lin Ma
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Jie Xiong
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
| | - Jinjin Wu
- Shanghai Children's Medical Center, Shanghai Jiaotong University, Shanghai, China
| | - Ling Liu
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China.
| | - Xiaoqing Zhang
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China; Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, China; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, Shanghai, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China; Key Laboratory of Neuroregeneration of Shanghai Universities, School of Medicine, Tongji University, Shanghai, China; Clinical Center for Brain and Spinal Cord Research, Tongji University, Shanghai, China.
| |
Collapse
|
2
|
Alshafei M, Schulze T, Morsi M, Panten U, Rustenbeck I. Short-Term Inhibition of Translation by Cycloheximide Concurrently Affects Mitochondrial Function and Insulin Secretion in Islets from Female Mice. Int J Mol Sci 2023; 24:15464. [PMID: 37895141 PMCID: PMC10607510 DOI: 10.3390/ijms242015464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/10/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Since glucose stimulates protein biosynthesis in beta cells concomitantly with the stimulation of insulin release, the possible interaction of both processes was explored. The protein biosynthesis was inhibited by 10 μM cycloheximide (CHX) 60 min prior to the stimulation of perifused, freshly isolated or 22 h-cultured NMRI mouse islets. CHX reduced the insulinotropic effect of 25 mM glucose or 500 μM tolbutamide in fresh but not in cultured islets. In cultured islets the second phase of glucose stimulation was even enhanced. In fresh and in cultured islets CHX strongly reduced the content of proinsulin, but not of insulin, and moderately diminished the [Ca2+]i increase during stimulation. The oxygen consumption rate (OCR) of fresh islets was about 50% higher than that of cultured islets at basal glucose and was significantly increased by glucose but not tolbutamide. In fresh, but not in cultured, islets CHX diminished the glucose-induced OCR increase and changes in the NAD(P)H- and FAD-autofluorescence. It is concluded that short-term CHX exposure interferes with the signal function of the mitochondria, which have different working conditions in fresh and in cultured islets. The interference may not be an off-target effect but may result from the inhibited cytosolic synthesis of mitochondrial proteins.
Collapse
Affiliation(s)
- Mohammed Alshafei
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.A.); (T.S.); (M.M.); (U.P.)
| | - Torben Schulze
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.A.); (T.S.); (M.M.); (U.P.)
| | - Mai Morsi
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.A.); (T.S.); (M.M.); (U.P.)
- Department of Pharmacology, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.A.); (T.S.); (M.M.); (U.P.)
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.A.); (T.S.); (M.M.); (U.P.)
| |
Collapse
|
3
|
Peterson SM, Juliana CA, Hu CF, Chai J, Holliday C, Chan KY, Lujan Hernandez AG, Challocombe Z, Wang L, Han Z, Haas N, Stafford R, Axelrod F, Yuan TZ, De León DD, Sato AK. Optimization of a Glucagon-Like Peptide 1 Receptor Antagonist Antibody for Treatment of Hyperinsulinism. Diabetes 2023; 72:1320-1329. [PMID: 37358194 PMCID: PMC10450825 DOI: 10.2337/db22-1039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 06/13/2023] [Indexed: 06/27/2023]
Abstract
Congenital hyperinsulinism (HI) is a genetic disorder in which pancreatic β-cell insulin secretion is excessive and results in hypoglycemia that, without treatment, can cause brain damage or death. Most patients with loss-of-function mutations in ABCC8 and KCNJ11, the genes encoding the β-cell ATP-sensitive potassium channel (KATP), are unresponsive to diazoxide, the only U.S. Food and Drug Administration-approved medical therapy and require pancreatectomy. The glucagon-like peptide 1 receptor (GLP-1R) antagonist exendin-(9-39) is an effective therapeutic agent that inhibits insulin secretion in both HI and acquired hyperinsulinism. Previously, we identified a highly potent antagonist antibody, TB-001-003, which was derived from our synthetic antibody libraries that were designed to target G protein-coupled receptors. Here, we designed a combinatorial variant antibody library to optimize the activity of TB-001-003 against GLP-1R and performed phage display on cells overexpressing GLP-1R. One antagonist, TB-222-023, is more potent than exendin-(9-39), also known as avexitide. TB-222-023 effectively decreased insulin secretion in primary isolated pancreatic islets from a mouse model of hyperinsulinism, Sur1-/- mice, and in islets from an infant with HI, and increased plasma glucose levels and decreased the insulin to glucose ratio in Sur1-/- mice. These findings demonstrate that targeting GLP-1R with an antibody antagonist is an effective and innovative strategy for treatment of hyperinsulinism. ARTICLE HIGHLIGHTS Patients with the most common and severe form of diazoxide-unresponsive congenital hyperinsulinism (HI) require a pancreatectomy. Other second-line therapies are limited in their use because of severe side effects and short half-lives. Therefore, there is a critical need for better therapies. Studies with the glucagon-like peptide 1 receptor (GLP-1R) antagonist, avexitide (exendin-(9-39)), have demonstrated that GLP-1R antagonism is effective at lowering insulin secretion and increasing plasma glucose levels. We have optimized a GLP-1R antagonist antibody with more potent blocking of GLP-1R than avexitide. This antibody therapy is a potential novel and effective treatment for HI.
Collapse
Affiliation(s)
| | - Christine A. Juliana
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | | | - Jinghua Chai
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | | | | | | | | | - Linya Wang
- Twist Bioscience, South San Francisco, CA
| | - Zhen Han
- Twist Bioscience, South San Francisco, CA
| | | | | | | | | | - Diva D. De León
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | | |
Collapse
|
4
|
Doliba NM, Rozo AV, Roman J, Qin W, Traum D, Gao L, Liu J, Manduchi E, Liu C, Golson ML, Vahedi G, Naji A, Matschinsky FM, Atkinson MA, Powers AC, Brissova M, Kaestner KH, Stoffers DA. α Cell dysfunction in islets from nondiabetic, glutamic acid decarboxylase autoantibody-positive individuals. J Clin Invest 2022; 132:156243. [PMID: 35642629 PMCID: PMC9151702 DOI: 10.1172/jci156243] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 04/14/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUNDMultiple islet autoantibodies (AAbs) predict the development of type 1 diabetes (T1D) and hyperglycemia within 10 years. By contrast, T1D develops in only approximately 15% of individuals who are positive for single AAbs (generally against glutamic acid decarboxylase [GADA]); hence, the single GADA+ state may represent an early stage of T1D.METHODSHere, we functionally, histologically, and molecularly phenotyped human islets from nondiabetic GADA+ and T1D donors.RESULTSSimilar to the few remaining β cells in the T1D islets, GADA+ donor islets demonstrated a preserved insulin secretory response. By contrast, α cell glucagon secretion was dysregulated in both GADA+ and T1D islets, with impaired glucose suppression of glucagon secretion. Single-cell RNA-Seq of GADA+ α cells revealed distinct abnormalities in glycolysis and oxidative phosphorylation pathways and a marked downregulation of cAMP-dependent protein kinase inhibitor β (PKIB), providing a molecular basis for the loss of glucose suppression and the increased effect of 3-isobutyl-1-methylxanthine (IBMX) observed in GADA+ donor islets.CONCLUSIONWe found that α cell dysfunction was present during the early stages of islet autoimmunity at a time when β cell mass was still normal, raising important questions about the role of early α cell dysfunction in the progression of T1D.FUNDINGThis work was supported by grants from the NIH (3UC4DK112217-01S1, U01DK123594-02, UC4DK112217, UC4DK112232, U01DK123716, and P30 DK019525) and the Vanderbilt Diabetes Research and Training Center (DK20593).
Collapse
Affiliation(s)
- Nicolai M. Doliba
- Department of Biochemistry and Biophysics,,Institute for Diabetes, Obesity, and Metabolism
| | - Andrea V. Rozo
- Institute for Diabetes, Obesity, and Metabolism,,Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine
| | | | - Wei Qin
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine
| | | | | | | | | | - Chengyang Liu
- Institute for Diabetes, Obesity, and Metabolism,,Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maria L. Golson
- Institute for Diabetes, Obesity, and Metabolism,,Department of Genetics, and
| | - Golnaz Vahedi
- Institute for Diabetes, Obesity, and Metabolism,,Department of Genetics, and
| | - Ali Naji
- Institute for Diabetes, Obesity, and Metabolism,,Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Franz M. Matschinsky
- Department of Biochemistry and Biophysics,,Institute for Diabetes, Obesity, and Metabolism
| | - Mark A. Atkinson
- Departments of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, Florida, USA.,Department of Pediatrics, University of Florida Diabetes Institute, College of Medicine, Gainesville, Florida, USA
| | - Alvin C. Powers
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA.,VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Marcela Brissova
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Klaus H. Kaestner
- Institute for Diabetes, Obesity, and Metabolism,,Department of Genetics, and
| | - Doris A. Stoffers
- Institute for Diabetes, Obesity, and Metabolism,,Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine
| | | |
Collapse
|
5
|
Rustenbeck I, Schulze T, Morsi M, Alshafei M, Panten U. What Is the Metabolic Amplification of Insulin Secretion and Is It (Still) Relevant? Metabolites 2021; 11:metabo11060355. [PMID: 34199454 PMCID: PMC8229681 DOI: 10.3390/metabo11060355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 12/24/2022] Open
Abstract
The pancreatic beta-cell transduces the availability of nutrients into the secretion of insulin. While this process is extensively modified by hormones and neurotransmitters, it is the availability of nutrients, above all glucose, which sets the process of insulin synthesis and secretion in motion. The central role of the mitochondria in this process was identified decades ago, but how changes in mitochondrial activity are coupled to the exocytosis of insulin granules is still incompletely understood. The identification of ATP-sensitive K+-channels provided the link between the level of adenine nucleotides and the electrical activity of the beta cell, but the depolarization-induced Ca2+-influx into the beta cells, although necessary for stimulated secretion, is not sufficient to generate the secretion pattern as produced by glucose and other nutrient secretagogues. The metabolic amplification of insulin secretion is thus the sequence of events that enables the secretory response to a nutrient secretagogue to exceed the secretory response to a purely depolarizing stimulus and is thus of prime importance. Since the cataplerotic export of mitochondrial metabolites is involved in this signaling, an orienting overview on the topic of nutrient secretagogues beyond glucose is included. Their judicious use may help to define better the nature of the signals and their mechanism of action.
Collapse
Affiliation(s)
- Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Correspondence: ; Tel.: +49-(0)53-139-156-70
| | - Torben Schulze
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Mai Morsi
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Department of Pharmacology, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Mohammed Alshafei
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| |
Collapse
|
6
|
Matschinsky F, Wilson D. Lifting the Veil on the "Phosphate Flush," a Cryptic Phenomenon of Experimental Pancreatic Islet Physiology. Diabetes 2021; 70:27-28. [PMID: 33355310 DOI: 10.2337/dbi20-0038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Franz Matschinsky
- Department of Biochemistry and Biophysics and the Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - David Wilson
- Department of Biochemistry and Biophysics and the Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| |
Collapse
|
7
|
Abstract
Na+/H+ exchangers (NHEs) are expressed in virtually all human tissues and organs. Two major tasks of those NHE isoforms that are located in plasma membranes are cell volume control by Na+-uptake and cellular pH regulation by H+-extrusion. Several NHEs, particularly NHE 1–4 and 8, are involved in the pathogenesis of diseases of the digestive system such as inflammatory bowel disease (ulcerative colitis, Crohn’s disease) and gastric and colorectal tumorigenesis. In the present review, we describe the physiological purposes, possible malfunctions and pathophysiological effects of the different NHE isoforms along the alimentary canal from esophagus to colon, including pancreas, liver and gallbladder. Particular attention is paid to the functions of NHEs in injury repair and to the role of NHE1 in Barrett’s esophagus. The impact of NHEs on gut microbiota and intestinal mucosal integrity is also dealt with. As the hitherto existing findings are not always consistent, sometimes even controversial, they are compared and critically discussed.
Collapse
Affiliation(s)
- Li Cao
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenglin Yuan
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mei Liu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Christian Stock
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hanover, Germany
| |
Collapse
|
8
|
Carlessi R, Rowlands J, Ellison G, Helena de Oliveira Alves H, Newsholme P, Mamotte C. Glutamine deprivation induces metabolic adaptations associated with beta cell dysfunction and exacerbate lipotoxicity. Mol Cell Endocrinol 2019; 491:110433. [PMID: 31018148 DOI: 10.1016/j.mce.2019.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/05/2019] [Accepted: 04/15/2019] [Indexed: 11/17/2022]
Abstract
Studies have reported that plasma glutamine is reduced in type 2 diabetes (T2D) patients. Glutamine supplementation improves glycaemic control, however the mechanisms are unclear. Here, we evaluated in vitro the pancreatic beta cell bioenergetic and insulin secretory responses to various levels of glutamine availability, or treatment in the presence of an inhibitor of intracellular glutamine metabolism. The impact of glutamine deprivation to the pathological events induced by the saturated fatty acid palmitate was also investigated. Glutamine deprivation induced a reduction in mitochondrial respiration and increase in glucose uptake and utilization. This phenotype was accompanied by impairment in beta cell function, as demonstrated by diminished insulin production and secretion, and activation of the unfolded protein response pathway. Palmitate led to insulin secretory dysfunction, loss of viability and apoptosis. Importantly, glutamine deprivation significantly exacerbated these phenotypes, suggesting that low glutamine levels could participate in the process of beta cell dysfunction in T2D.
Collapse
Affiliation(s)
- Rodrigo Carlessi
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
| | - Jordan Rowlands
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia
| | - Gaewyn Ellison
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia
| | | | - Philip Newsholme
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
| | - Cyril Mamotte
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, Western Australia, 6845, Australia.
| |
Collapse
|
9
|
Schulze T, Mattern K, Früh E, Hecht L, Rustenbeck I, Dietzel A. A 3D microfluidic perfusion system made from glass for multiparametric analysis of stimulus-secretioncoupling in pancreatic islets. Biomed Microdevices 2018; 19:47. [PMID: 28540469 DOI: 10.1007/s10544-017-0186-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microfluidic perfusion systems (MPS) are well suited to perform multiparametric measurements with small amounts of tissue to function as an Organ on Chip device (OOC). Such microphysiolgical characterization is particularly valuable in research on the stimulus-secretion-coupling of pancreatic islets. Pancreatic islets are fully functional competent mini-organs, which serve as fuel sensors and transduce metabolic activity into rates of hormone secretion. To enable the simultaneous measurement of fluorescence and oxygen consumption we designed a microfluidic perfusion system from borosilicate glass by 3D femtosecond laser ablation. Retention of islets was accomplished by a plain well design. The characteristics of flow and shear force in the microchannels and wells were simulated and compared with the measured exchange of the perfusion media. Distribution of latex beads, MIN6 cell pseudo islets and isolated mouse islets in the MPS was characterized in dependence of flow rate and well depth. Overall, the observations suggested that a sufficient retention of the islets at low shear stress, together with sufficient exchange of test medium, was achieved at a well depth of 300 μm and perfusion rates between 40 and 240 μl/min. This enabled multiparametric measurement of oxygen consumption, NAD(P)H autofluorescence, cytosolic Ca2+ concentration, and insulin secretion by isolated mouse islets. After appropriate correction for different lag times, kinetics of these processes could be compared. Such measurements permit a more precise insight into metabolic changes underlying the regulation of insulin secretion. Thus, rapid prototyping using laser ablation enables flexible adaption of borosilicate MPS designs to different demands of biomedical research.
Collapse
Affiliation(s)
- Torben Schulze
- Institute of Pharmacology and Toxicology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany.,Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Kai Mattern
- Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, 38106, Braunschweig, Germany.,Institute of Microtechnology, Technische Universität Braunschweig, Alte Salzdahlumer Str. 203, 38124, Braunschweig, Germany
| | - Eike Früh
- Institute of Pharmacology and Toxicology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Lars Hecht
- Institute of Microtechnology, Technische Universität Braunschweig, Alte Salzdahlumer Str. 203, 38124, Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany. .,Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, 38106, Braunschweig, Germany.
| | - Andreas Dietzel
- Center of Pharmaceutical Engineering (PVZ), Technische Universität Braunschweig, 38106, Braunschweig, Germany. .,Institute of Microtechnology, Technische Universität Braunschweig, Alte Salzdahlumer Str. 203, 38124, Braunschweig, Germany.
| |
Collapse
|
10
|
Abstract
Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function.
Collapse
Affiliation(s)
- Brit H Boehmer
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical SciencesUniversity of Arizona, Tucson, Arizona, USA
| | - Paul J Rozance
- Department of PediatricsPerinatal Research Center, University of Colorado School of Medicine, Aurora, Colorado, USA
| |
Collapse
|
11
|
Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
Collapse
Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| |
Collapse
|
12
|
Schulze T, Morsi M, Reckers K, Brüning D, Seemann N, Panten U, Rustenbeck I. Metabolic amplification of insulin secretion is differentially desensitized by depolarization in the absence of exogenous fuels. Metabolism 2017; 67:1-13. [PMID: 28081772 DOI: 10.1016/j.metabol.2016.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The metabolic amplification of insulin secretion is the sequence of events which enables the secretory response to a fuel secretagogue to exceed the secretory response to a purely depolarizing stimulus. The signals in this pathway are incompletely understood. Here, we have characterized an experimental procedure by which the amplifying response to glucose is reversibly desensitized, while the response to α-ketoisocaproic acid (KIC) is unchanged. MATERIALS/METHODS Insulin secretion, NAD(P)H- and FAD-autofluorescence, Fura-2 fluorescence and oxygen consumption were measured in perifused NMRI mouse islets. The ATP- and ADP-contents were measured in statically incubated mouse islets. All islets were freshly isolated. RESULTS While the original observation on the dissociation between glucose- and KIC-amplification was obtained with islets that had been exposed to a high concentration of the sulfonylurea glipizide in the absence of glucose, we now show that in the absence of exogenous fuel a moderate depolarization, irrespective of its mechanism, progressively decreased the amplification in response to both glucose and KIC. However, the amplification in response to glucose declined faster, so a time window exists where glucose was already inefficient, whereas KIC was of unimpaired efficiency. Measurements of adenine nucleotides, NAD(P)H- and FAD-autofluorescence, and oxygen consumption point to a central role of the mitochondrial metabolism in this process. The desensitization could be quickly reversed by increasing oxidative deamination of glutamate and consequently anaplerosis of the citrate cycle. CONCLUSION Depolarization in the absence of exogenous fuel may be a useful model to identify those signals which are indispensable for the generation of metabolic amplification.
Collapse
Affiliation(s)
- Torben Schulze
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Mai Morsi
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Kirstin Reckers
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Dennis Brüning
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Nele Seemann
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Uwe Panten
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany.
| |
Collapse
|
13
|
Schulze T, Morsi M, Brüning D, Schumacher K, Rustenbeck I. Different responses of mouse islets and MIN6 pseudo-islets to metabolic stimulation: a note of caution. Endocrine 2016; 51:440-7. [PMID: 26227244 DOI: 10.1007/s12020-015-0701-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/20/2015] [Indexed: 11/25/2022]
Abstract
MIN6 cells and MIN6 pseudo-islets are popular surrogates for the use of primary beta cells and islets. Even though it is generally agreed that the stimulus-secretion coupling may deviate from that of beta cells or islets, direct comparisons are rare. The present side-by-side comparison of insulin secretion, cytosolic Ca(2+) concentration ([Ca(2+)] i ) and oxygen consumption rate (OCR) points out where similarities and differences exist between MIN6 cells and normal mouse beta cells. In mouse islets and MIN6 pseudo-islets depolarization by 40 mM KCl was a more robust insulinotropic stimulus than 30 mM glucose. In MIN6 pseudo-islets, but not in mouse islets, the response to 30 mM glucose was much lower than to 40 mM KCl and could be suppressed by a preceding stimulation with 40 mM KCl. In MIN6 pseudo-islets, glucose was less effective to raise [Ca(2+)] i than in primary islets. In marked contrast to islets, the OCR response of MIN6 pseudo-islets to 30 mM glucose was smaller than to 40 mM KCl and was further diminished by a preceding stimulation with 40 mM KCl. The same pattern was observed when MIN6 pseudo-islets were cultured in 5 mM glucose. As with insulin secretion memory effects on the OCR remained after wash-out of a stimulus. The differences between MIN6 cells and primary beta cells were generally larger in the responses to glucose than to depolarization by KCl. Thus, the use of MIN6 cells in investigations on metabolic signalling requires particular caution.
Collapse
Affiliation(s)
- Torben Schulze
- Institute of Pharmacology and Toxicology and Center of Pharmaceutical Engineering, University of Braunschweig, Mendelssohnstr. 1, 38106, Brunswick, Germany
| | - Mai Morsi
- Institute of Pharmacology and Toxicology and Center of Pharmaceutical Engineering, University of Braunschweig, Mendelssohnstr. 1, 38106, Brunswick, Germany
| | - Dennis Brüning
- Institute of Pharmacology and Toxicology and Center of Pharmaceutical Engineering, University of Braunschweig, Mendelssohnstr. 1, 38106, Brunswick, Germany
| | - Kirstin Schumacher
- Institute of Pharmacology and Toxicology and Center of Pharmaceutical Engineering, University of Braunschweig, Mendelssohnstr. 1, 38106, Brunswick, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology and Center of Pharmaceutical Engineering, University of Braunschweig, Mendelssohnstr. 1, 38106, Brunswick, Germany.
| |
Collapse
|
14
|
Doliba NM, Liu Q, Li C, Chen J, Chen P, Liu C, Frederick DW, Baur JA, Bennett MJ, Naji A, Matschinsky FM. Accumulation of 3-hydroxytetradecenoic acid: Cause or corollary of glucolipotoxic impairment of pancreatic β-cell bioenergetics? Mol Metab 2015; 4:926-39. [PMID: 26909309 PMCID: PMC4731732 DOI: 10.1016/j.molmet.2015.09.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 09/16/2015] [Accepted: 09/25/2015] [Indexed: 12/20/2022] Open
Abstract
Objectives Hyperglycemia and elevated blood lipids are the presumed precipitating causes of β-cell damage in T2DM as the result of a process termed “glucolipotoxicity”. Here, we tested whether glucolipotoxic pathophysiology is caused by defective bioenergetics using islets in culture. Methods Insulin secretion, respiration, ATP generation, fatty acid (FA) metabolite profiles and gene expression were determined in isolated islets treated under glucolipotoxic culture conditions. Results Over time, chronic exposure of mouse islets to FAs with glucose leads to bioenergetic failure and reduced insulin secretion upon stimulation with glucose or amino acids. Islets exposed to glucolipotoxic conditions displayed biphasic changes of the oxygen consumption rate (OCR): an initial increase in baseline and Vmax of OCR after 3 days, followed by decreased baseline and glucose stimulated OCR after 5 days. These changes were associated with lower islet ATP levels, impaired glucose-induced ATP generation, a trend for reduced mitochondrial DNA content and reduced expression of mitochondrial transcription factor A (Tfam). We discovered the accumulation of carnitine esters of hydroxylated long chain FAs, in particular 3-hydroxytetradecenoyl-carnitine. Conclusions As long chain 3-hydroxylated FA metabolites are known to uncouple heart and brain mitochondria [53], [54], [55], we propose that under glucolipotoxic condition, unsaturated hydroxylated long-chain FAs accumulate, uncouple and ultimately inhibit β-cell respiration. This leads to the slow deterioration of mitochondrial function progressing to bioenergetics β-cell failure. We found low capacity of islets to generate ATP after glucolipotoxic treatment. Found biphasic (up/down) respiratory time course as expression of glucolipotoxicity. We found β-Hydroxylated long FA metabolites as new glucolipotoxicity mediators. β-Hydroxylated long FAs are known to uncouple Ox/Phos. We propose defective bioenergetics as main cause of glucolipotoxicity.
Collapse
Affiliation(s)
- Nicolai M. Doliba
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
- Corresponding author. University of Pennsylvania, Biochemistry/Biophysics, 3400 Civic Center Blvd, Smilow Center for Translation Research, TRC12-131, Philadelphia, PA 19104, United States. Tel.: +1 215 898 4366; fax: +1 215 898 5408.
| | - Qing Liu
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| | - Changhong Li
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Jie Chen
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Pan Chen
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Chengyang Liu
- Department of Surgery, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| | - David W. Frederick
- Department of Physiology, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| | - Joseph A. Baur
- Department of Physiology, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| | - Michael J. Bennett
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Ali Naji
- Department of Surgery, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| | - Franz M. Matschinsky
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, United States
- Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania School of Medicine, United States
| |
Collapse
|
15
|
Wauson EM, Guerra ML, Dyachok J, McGlynn K, Giles J, Ross EM, Cobb MH. Differential Regulation of ERK1/2 and mTORC1 Through T1R1/T1R3 in MIN6 Cells. Mol Endocrinol 2015; 29:1114-22. [PMID: 26168033 DOI: 10.1210/me.2014-1181] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The MAPKs ERK1/2 respond to nutrients and other insulin secretagogues in pancreatic β-cells and mediate nutrient-dependent insulin gene transcription. Nutrients also stimulate the mechanistic target of rapamycin complex 1 (mTORC1) to regulate protein synthesis. We showed previously that activation of both ERK1/2 and mTORC1 in the MIN6 pancreatic β-cell-derived line by extracellular amino acids (AAs) is at least in part mediated by the heterodimeric T1R1/T1R3, a G protein-coupled receptor. We show here that AAs differentially activate these two signaling pathways in MIN6 cells. Pretreatment with pertussis toxin did not prevent the activation of either ERK1/2 or mTORC1 by AAs, indicating that G(I) is not central to either pathway. Although glucagon-like peptide 1, an agonist for a G(s-)coupled receptor, activated ERK1/2 well and mTORC1 to a small extent, AAs had no effect on cytosolic cAMP accumulation. Ca(2+) entry is required for ERK1/2 activation by AAs but is dispensable for AA activation of mTORC1. Pretreatment with UBO-QIC, a selective G(q) inhibitor, reduced the activation of ERK1/2 but had little effect on the activation of mTORC1 by AAs, suggesting a differential requirement for G(q). Inhibition of G(12/13) by the overexpression of the regulator of G protein signaling domain of p115 ρ-guanine nucleotide exchange factor had no effect on mTORC1 activation by AAs, suggesting that these G proteins are also not involved. We conclude that AAs regulate ERK1/2 and mTORC1 through distinct signaling pathways.
Collapse
Affiliation(s)
- Eric M Wauson
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Marcy L Guerra
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Julia Dyachok
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Kathleen McGlynn
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Jennifer Giles
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Elliott M Ross
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| | - Melanie H Cobb
- Department of Pharmacology (E.M.W., M.L.G., J.D., K.M., E.M.R., M.H.C.) and the Green Center for Systems Biology (J.D., E.M.R.), University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041; and Department of Physiology and Pharmacology (E.M.W., J.G.), Des Moines University, Des Moines, Iowa 50312
| |
Collapse
|
16
|
Hao K, Kong FP, Gao YQ, Tang JW, Chen J, Evans AM, Lightman SL, Chen XQ, Du JZ. Inactivation of corticotropin-releasing hormone-induced insulinotropic role by high-altitude hypoxia. Diabetes 2015; 64:785-95. [PMID: 25277397 DOI: 10.2337/db14-0500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have shown that hypoxia reduces plasma insulin, which correlates with corticotropin-releasing hormone (CRH) receptor 1 (CRHR1) in rats, but the mechanism remains unclear. Here, we report that hypobaric hypoxia at an altitude of 5,000 m for 8 h enhances rat plasma CRH, corticosterone, and glucose levels, whereas the plasma insulin and pancreatic ATP/ADP ratio is reduced. In islets cultured under normoxia, CRH stimulated insulin release in a glucose- and CRH-level-dependent manner by activating CRHR1 and thus the cAMP-dependent protein kinase pathway and calcium influx through L-type channels. In islets cultured under hypoxia, however, the insulinotropic effect of CRH was inactivated due to reduced ATP and cAMP and coincident loss of intracellular calcium oscillations. Serum and glucocorticoid-inducible kinase 1 (SGK1) also played an inhibitory role. In human volunteers rapidly ascended to 3,860 m, plasma CRH and glucose levels increased without a detectable change in plasma insulin. By contrast, volunteers with acute mountain sickness (AMS) exhibited a marked decrease in HOMA insulin sensitivity (HOMA-IS) and enhanced plasma CRH. In conclusion, hypoxia may attenuate the CRH-insulinotropic effect by reducing cellular ATP/ADP ratio, cAMP and calcium influx, and upregulated SGK1. Hypoxia may not affect HOMA-IS in healthy volunteers but reduces it in AMS volunteers.
Collapse
Affiliation(s)
- Ke Hao
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Fan-Ping Kong
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Yu-Qi Gao
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China
| | - Jia-Wei Tang
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Jian Chen
- Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China
| | - A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, U.K
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, U.K
| | - Xue-Qun Chen
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| | - Ji-Zeng Du
- Division of Neurobiology and Physiology, Department of Basic Medical Sciences, School of Medicine, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University, Hangzhou, China
| |
Collapse
|
17
|
|
18
|
De Marchi U, Thevenet J, Hermant A, Dioum E, Wiederkehr A. Calcium co-regulates oxidative metabolism and ATP synthase-dependent respiration in pancreatic beta cells. J Biol Chem 2014; 289:9182-94. [PMID: 24554722 PMCID: PMC3979381 DOI: 10.1074/jbc.m113.513184] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mitochondrial energy metabolism is essential for glucose-induced calcium signaling and, therefore, insulin granule exocytosis in pancreatic beta cells. Calcium signals are sensed by mitochondria acting in concert with mitochondrial substrates for the full activation of the organelle. Here we have studied glucose-induced calcium signaling and energy metabolism in INS-1E insulinoma cells and human islet beta cells. In insulin secreting cells a surprisingly large fraction of total respiration under resting conditions is ATP synthase-independent. We observe that ATP synthase-dependent respiration is markedly increased after glucose stimulation. Glucose also causes a very rapid elevation of oxidative metabolism as was followed by NAD(P)H autofluorescence. However, neither the rate of the glucose-induced increase nor the new steady-state NAD(P)H levels are significantly affected by calcium. Our findings challenge the current view, which has focused mainly on calcium-sensitive dehydrogenases as the target for the activation of mitochondrial energy metabolism. We propose a model of tight calcium-dependent regulation of oxidative metabolism and ATP synthase-dependent respiration in beta cell mitochondria. Coordinated activation of matrix dehydrogenases and respiratory chain activity by calcium allows the respiratory rate to change severalfold with only small or no alterations of the NAD(P)H/NAD(P)(+) ratio.
Collapse
|
19
|
Abstract
The pancreatic islet β cell senses circulating levels of calorigenic nutrients to secrete insulin according to the needs of the organism. Altered insulin secretion is linked to various disorders such as diabetes, hypoglycemic states, and cardiometabolic diseases. Fuel stimuli, including glucose, free fatty acids, and amino acids, promote insulin granule exocytosis primarily via their metabolism in β cells and the production of key signaling metabolites. This paper reviews our current knowledge of the pathways involved in both positive and negative metabolic signaling for insulin secretion and assesses the role of established and candidate metabolic coupling factors, keeping recent developments in focus.
Collapse
Affiliation(s)
- Marc Prentki
- Molecular Nutrition Unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, QC, Canada.
| | | | | |
Collapse
|
20
|
Sun YM, Su Y, Li J, Tian Y, Wang LF. Role of the Na+/H+ exchanger on the development of diabetes mellitus and its chronic complications. Biochem Biophys Res Commun 2012; 427:229-31. [DOI: 10.1016/j.bbrc.2012.09.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 09/08/2012] [Indexed: 11/28/2022]
|
21
|
Akhmedov D, Braun M, Mataki C, Park KS, Pozzan T, Schoonjans K, Rorsman P, Wollheim CB, Wiederkehr A. Mitochondrial matrix pH controls oxidative phosphorylation and metabolism-secretion coupling in INS-1E clonal beta cells. FASEB J 2010; 24:4613-26. [PMID: 20647546 DOI: 10.1096/fj.10-162222] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Glucose-evoked mitochondrial signals augment ATP synthesis in the pancreatic β cell. This activation of energy metabolism increases the cytosolic ATP/ADP ratio, which stimulates plasma membrane electrical activity and insulin granule exocytosis. We have recently demonstrated that matrix pH increases during nutrient stimulation of the pancreatic β cell. Here, we have tested whether mitochondrial matrix pH controls oxidative phosphorylation and metabolism-secretion coupling in the rat β-cell line INS-1E. Acidification of the mitochondrial matrix pH by nigericin blunted nutrient-dependent respiratory and ATP responses (continuously monitored in intact cells). Using electrophysiology and single cell imaging, we find that the associated defects in energy metabolism suppress glucose-stimulated plasma membrane electrical activity and cytosolic calcium transients. The same parameters were unaffected after direct stimulation of electrical activity with tolbutamide, which bypasses mitochondrial function. Furthermore, lowered matrix pH strongly inhibited sustained, but not first-phase, insulin secretion. Our results demonstrate that the matrix pH exerts a control function on oxidative phosphorylation in intact cells and that this mode of regulation is of physiological relevance for the generation of downstream signals leading to insulin granule exocytosis. We propose that matrix pH serves a novel signaling role in sustained cell activation.
Collapse
Affiliation(s)
- Dmitry Akhmedov
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
De León DD, Li C, Delson MI, Matschinsky FM, Stanley CA, Stoffers DA. Exendin-(9-39) corrects fasting hypoglycemia in SUR-1-/- mice by lowering cAMP in pancreatic beta-cells and inhibiting insulin secretion. J Biol Chem 2008; 283:25786-93. [PMID: 18635551 DOI: 10.1074/jbc.m804372200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Congenital hyperinsulinism is a disorder of pancreatic beta-cell function characterized by failure to suppress insulin secretion in the setting of hypoglycemia, resulting in brain damage or death if untreated. Loss-of-function mutations in the K(ATP) channel (composed of two subunits: Kir6.2 and SUR-1) are responsible for the most common and severe form of congenital hyperinsulinism. Most patients are unresponsive to available medical therapy and require palliative pancreatectomy. Similar to the human condition, the SUR-1(-/-) mouse is hypoglycemic when fasted and hyperglycemic when glucose-loaded. We have previously reported that the glucagon-like peptide-1 receptor antagonist exendin-(9-39) raises fasting blood glucose in normal mice. Here we examine the effect of exendin-(9-39) on fasting blood glucose in SUR-1(-/-) mice. Mice were randomized to receive exendin-(9-39) or vehicle. Fasting blood glucose levels in SUR-1(-/-) mice treated with exendin-(9-39) were significantly higher than in vehicle-treated mice and not different from wild-type littermates. Exendin-(9-39) did not further worsen glucose tolerance and had no effect on body weight and insulin sensitivity. Isolated islet perifusion studies demonstrated that exendin-(9-39) blocked amino acid-stimulated insulin secretion, which is abnormally increased in SUR-1(-/-) islets. Furthermore, cAMP content in SUR-1(-/-) islets was reduced by exendin-(9-39) both basally and when stimulated by amino acids, whereas cytosolic calcium levels were not affected. These findings suggest that cAMP plays a key role in K(ATP)-independent insulin secretion and that the GLP-1 receptor is constitutively active in SUR-1(-/-) beta-cells. Our findings indicate that exendin-(9-39) normalizes fasting hypoglycemia in SUR-1(-/-) mice via a direct effect on insulin secretion, thereby raising exendin-(9-39) as a potential therapeutic agent for K(ATP) hyperinsulinism.
Collapse
Affiliation(s)
- Diva D De León
- Division of Endocrinology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Diederichs F. Ion homeostasis and the functional roles of SERCA reactions in stimulus–secretion coupling of the pancreatic β-cell. Biophys Chem 2008; 134:119-43. [DOI: 10.1016/j.bpc.2008.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2007] [Revised: 01/20/2008] [Accepted: 02/04/2008] [Indexed: 10/22/2022]
|
24
|
Li C, Nissim I, Chen P, Buettger C, Najafi H, Daikhin Y, Nissim I, Collins HW, Yudkoff M, Stanley CA, Matschinsky FM. Elimination of KATP channels in mouse islets results in elevated [U-13C]glucose metabolism, glutaminolysis, and pyruvate cycling but a decreased gamma-aminobutyric acid shunt. J Biol Chem 2008; 283:17238-49. [PMID: 18445600 DOI: 10.1074/jbc.m709235200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pancreatic beta cells are hyper-responsive to amino acids but have decreased glucose sensitivity after deletion of the sulfonylurea receptor 1 (SUR1) both in man and mouse. It was hypothesized that these defects are the consequence of impaired integration of amino acid, glucose, and energy metabolism in beta cells. We used gas chromatography-mass spectrometry methodology to study intermediary metabolism of SUR1 knock-out (SUR1(-/-)) and control mouse islets with d-[U-(13)C]glucose as substrate and related the results to insulin secretion. The levels and isotope labeling of alanine, aspartate, glutamate, glutamine, and gamma-aminobutyric acid (GABA) served as indicators of intermediary metabolism. We found that the GABA shunt of SUR1(-/-) islets is blocked by about 75% and showed that this defect is due to decreased glutamate decarboxylase synthesis, probably caused by elevated free intracellular calcium. Glutaminolysis stimulated by the leucine analogue d,l-beta-2-amino-2-norbornane-carboxylic acid was, however, enhanced in SUR1(-/-) and glyburide-treated SUR1(+/+) islets. Glucose oxidation and pyruvate cycling was increased in SUR1(-/-) islets at low glucose but was the same as in controls at high glucose. Malic enzyme isoforms 1, 2, and 3, involved in pyruvate cycling, were all expressed in islets. High glucose lowered aspartate and stimulated glutamine synthesis similarly in controls and SUR1(-/-) islets. The data suggest that the interruption of the GABA shunt and the lack of glucose regulation of pyruvate cycling may cause the glucose insensitivity of the SUR1(-/-) islets but that enhanced basal pyruvate cycling, lowered GABA shunt flux, and enhanced glutaminolytic capacity may sensitize the beta cells to amino acid stimulation.
Collapse
Affiliation(s)
- Changhong Li
- Division of Endocrinology, The Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Stiernet P, Nenquin M, Moulin P, Jonas JC, Henquin JC. Glucose-induced cytosolic pH changes in beta-cells and insulin secretion are not causally related: studies in islets lacking the Na+/H+ exchangeR NHE1. J Biol Chem 2007; 282:24538-46. [PMID: 17599909 DOI: 10.1074/jbc.m702862200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The contribution of Na(+)/H(+) exchange (achieved by NHE proteins) to the regulation of beta-cell cytosolic pH(c), and the role of pH(c) changes in glucose-induced insulin secretion are disputed and were examined here. Using real-time PCR, we identified plasmalemmal NHE1 and intracellular NHE7 as the two most abundant NHE isoforms in mouse islets. We, therefore, compared insulin secretion, cytosolic free Ca(2+) ([Ca(2+)](c)) and pH(c) in islets from normal mice and mice bearing an inactivating mutation of NHE1 (Slc9A1-swe/swe). The experiments were performed in HCO(-)(3)/CO(2) or HEPES/NaOH buffers. PCR and functional approaches showed that NHE1 mutant islets do not express compensatory pH-regulating mechanisms. NHE1 played a greater role than HCO(-)(3)-dependent mechanisms in the correction of an acidification imposed by a pulse of NH(4)Cl. In contrast, basal pH(c) (in low glucose) and the alkalinization produced by high glucose were independent of NHE1. Dimethylamiloride, a classic blocker of Na(+)/H(+) exchange, did not affect pH(c) but increased insulin secretion in NHE1 mutant islets, indicating unspecific effects. In control islets, glucose similarly increased [Ca(2+)](c) and insulin secretion in HCO(-)(3) and HEPES buffer, although pH(c) changed in opposite directions. The amplification of insulin secretion that glucose produces when [Ca(2+)](c) is clamped at an elevated level by KCl was also unrelated to pH(c) and pH(c) changes. All effects of glucose on [Ca(2+)](c) and insulin secretion proved independent of NHE1. In conclusion, NHE1 protects beta-cells against strong acidification, but has no role in stimulus-secretion coupling. The changes in pH(c) produced by glucose involve HCO(-)(3)-dependent mechanisms. Variations in beta-cell pH(c) are not causally related to changes in insulin secretion.
Collapse
Affiliation(s)
- Patrick Stiernet
- Unit of Endocrinology and Metabolism, University of Louvain Faculty of Medicine, UCL 55.30, B-1200 Brussels, Belgium
| | | | | | | | | |
Collapse
|