1
|
Vishnu N, Hamilton A, Bagge A, Wernersson A, Cowan E, Barnard H, Sancak Y, Kamer KJ, Spégel P, Fex M, Tengholm A, Mootha VK, Nicholls DG, Mulder H. Mitochondrial clearance of calcium facilitated by MICU2 controls insulin secretion. Mol Metab 2021; 51:101239. [PMID: 33932586 PMCID: PMC8163986 DOI: 10.1016/j.molmet.2021.101239] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Transport of Ca2+ into pancreatic β cell mitochondria facilitates nutrient-mediated insulin secretion. However, the underlying mechanism is unclear. Recent establishment of the molecular identity of the mitochondrial Ca2+ uniporter (MCU) and associated proteins allows modification of mitochondrial Ca2+ transport in intact cells. We examined the consequences of deficiency of the accessory protein MICU2 in rat and human insulin-secreting cells and mouse islets. METHODS siRNA silencing of Micu2 in the INS-1 832/13 and EndoC-βH1 cell lines was performed; Micu2-/- mice were also studied. Insulin secretion and mechanistic analyses utilizing live confocal imaging to assess mitochondrial function and intracellular Ca2+ dynamics were performed. RESULTS Silencing of Micu2 abrogated GSIS in the INS-1 832/13 and EndoC-βH1 cells. The Micu2-/- mice also displayed attenuated GSIS. Mitochondrial Ca2+ uptake declined in MICU2-deficient INS-1 832/13 and EndoC-βH1 cells in response to high glucose and high K+. MICU2 silencing in INS-1 832/13 cells, presumably through its effects on mitochondrial Ca2+ uptake, perturbed mitochondrial function illustrated by absent mitochondrial membrane hyperpolarization and lowering of the ATP/ADP ratio in response to elevated glucose. Despite the loss of mitochondrial Ca2+ uptake, cytosolic Ca2+ was lower in siMICU2-treated INS-1 832/13 cells in response to high K+. It was hypothesized that Ca2+ accumulated in the submembrane compartment in MICU2-deficient cells, resulting in desensitization of voltage-dependent Ca2+ channels, lowering total cytosolic Ca2+. Upon high K+ stimulation, MICU2-silenced cells showed higher and prolonged increases in submembrane Ca2+ levels. CONCLUSIONS MICU2 plays a critical role in β cell mitochondrial Ca2+ uptake. β cell mitochondria sequestered Ca2+ from the submembrane compartment, preventing desensitization of voltage-dependent Ca2+ channels and facilitating GSIS.
Collapse
Affiliation(s)
- N Vishnu
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - A Hamilton
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - A Bagge
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - A Wernersson
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - E Cowan
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - H Barnard
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - Y Sancak
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - K J Kamer
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - P Spégel
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - M Fex
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden
| | - A Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala SE-751 23, Sweden
| | - V K Mootha
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - D G Nicholls
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden; Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - H Mulder
- Unit of Molecular Metabolism, Lund University Diabetes Center, Lund University, Malmö SE-205 02, Sweden.
| |
Collapse
|
2
|
Winkel L, Bagge A, Larsen L, Haase TN, Rasmussen M, Lykke J, Holmgaard DB, Thim L, Nielsen JH, Dalgaard LT. Trefoil factor 3 in perinatal pancreas is increased by gestational low protein diet and associated with accelerated β-cell maturation. Islets 2018; 10:e1472186. [PMID: 29723130 PMCID: PMC5989913 DOI: 10.1080/19382014.2018.1472186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The endocrine pancreas expands markedly in the first postnatal days and the insulin producing β-cells initiate a functional maturation preceded by a morphological change of the islets of Langerhans. Trefoil factor 3 (TFF3) is a secreted peptide expressed in intestinal epithelia, where it promotes migration, but its role in the pancreas is not characterized. The aim of this study was to examine the expression and function of TFF3 in perinatal rat pancreas, ex vivo cultured fetal rat pancreas and in the rat β-cell line INS-1E. Control or gestational low-protein diet perinatal rat pancreas was harvested at embryonic day 20 (E20), day of birth (P0) and postnatal day 2 (P2). TFF3 mRNA was upregulated 4.5-fold at P0 vs. E20 and downregulated again at P2. In protein-undernourished pups induction of TFF3 at P0 was further increased to 9.7-fold and was increased at P2. TFF3 caused tyrosine phosphorylation of EGFR in INS-1E β-cells, and purified recombinant TFF3 increased both attachment and spreading of INS-1E β-cells. In ex vivo cultures of collagenase digested fetal rat pancreas, a model of perinatal β-cell maturation, TFF3 increased cellular spreading as well as insulin mRNA levels. TFF3 also increased the expression of Pref1/Dlk1 that shares similarities in expression and regulation with TFF3. These results suggest that TFF3 may promote adhesion and spreading of cells to accelerate β-cell maturation. This study indicates a functional role for TFF3 in pancreatic β-cell maturation in the perinatal period, which is altered by low protein diet during gestation.
Collapse
Affiliation(s)
- Louise Winkel
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Annika Bagge
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Louise Larsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tobias N. Haase
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Rasmussen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jeanette Lykke
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dennis B. Holmgaard
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Lars Thim
- Biopharmaceutical Research Unit, Novo Nordisk A/S, Måløv, Denmark
| | - Jens H. Nielsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Louise T. Dalgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
- CONTACT Louise T. Dalgaard Department of Science and Environment, Roskilde University Bldg. 28.1, PO box 260, Universitetsvej 1, DK-4000 Roskilde, Denmark
| |
Collapse
|
3
|
Axelsson AS, Mahdi T, Nenonen HA, Singh T, Hänzelmann S, Wendt A, Bagge A, Reinbothe TM, Millstein J, Yang X, Zhang B, Gusmao EG, Shu L, Szabat M, Tang Y, Wang J, Salö S, Eliasson L, Artner I, Fex M, Johnson JD, Wollheim CB, Derry JMJ, Mecham B, Spégel P, Mulder H, Costa IG, Zhang E, Rosengren AH. Sox5 regulates beta-cell phenotype and is reduced in type 2 diabetes. Nat Commun 2017; 8:15652. [PMID: 28585545 PMCID: PMC5467166 DOI: 10.1038/ncomms15652] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/10/2017] [Indexed: 01/09/2023] Open
Abstract
Type 2 diabetes (T2D) is characterized by insulin resistance and impaired insulin secretion, but the mechanisms underlying insulin secretion failure are not completely understood. Here, we show that a set of co-expressed genes, which is enriched for genes with islet-selective open chromatin, is associated with T2D. These genes are perturbed in T2D and have a similar expression pattern to that of dedifferentiated islets. We identify Sox5 as a regulator of the module. Sox5 knockdown induces gene expression changes similar to those observed in T2D and diabetic animals and has profound effects on insulin secretion, including reduced depolarization-evoked Ca2+-influx and β-cell exocytosis. SOX5 overexpression reverses the expression perturbations observed in a mouse model of T2D, increases the expression of key β-cell genes and improves glucose-stimulated insulin secretion in human islets from donors with T2D. We suggest that human islets in T2D display changes reminiscent of dedifferentiation and highlight SOX5 as a regulator of β-cell phenotype and function.
Collapse
Affiliation(s)
- A S Axelsson
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T Mahdi
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Medical Research Center, Hawler Medical University, 44001 Erbil, Iraq
| | - H A Nenonen
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T Singh
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - S Hänzelmann
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - A Wendt
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - A Bagge
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - T M Reinbothe
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - J Millstein
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA
| | - X Yang
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Dr East, Los Angeles, California 90095, USA
| | - B Zhang
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Genetics and Genomic Sciences, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, New York 10029, USA
| | - E G Gusmao
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - L Shu
- Department of Integrative Biology and Physiology, University of California, Los Angeles, 610 Charles E. Young Dr East, Los Angeles, California 90095, USA
| | - M Szabat
- Diabetes Research Group, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Y Tang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Key Lab of Hormones and Development, Ministry of Health, Metabolic Diseases Hospital, Tianjin Medical University, Tianjin 300070, China
| | - J Wang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Department of Emergency, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, China
| | - S Salö
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - L Eliasson
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - I Artner
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - M Fex
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - J D Johnson
- Diabetes Research Group, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 5358-2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - C B Wollheim
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Department of Cell Physiology and Metabolism, University Medical Center, Rue Michel-Servet 1, 1206 Geneva, Switzerland
| | - J M J Derry
- Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA
| | - B Mecham
- Trialomics, 6310 12th Avenue NE, Seattle, Washington 98115, USA
| | - P Spégel
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Centre for Analysis and Synthesis, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden
| | - H Mulder
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - I G Costa
- Institute of Biomedical Engineering, RWTH Aachen University Hospital, Pauwelstr 19, 52074 Aachen, Germany
| | - E Zhang
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden
| | - A H Rosengren
- Lund University Diabetes Center, CRC 91-11 SUS, Jan Waldenströms gata 35, SE-20502 Malmö, Sweden.,Sage Bionetworks, 1100 Fairview Avenue N, Seattle, Washington 98109, USA.,Department of Neuroscience and Physiology, University of Gothenburg, Box 100, SE-405 30 Gothenburg, Sweden
| |
Collapse
|
4
|
Ofori JK, Salunkhe VA, Bagge A, Vishnu N, Nagao M, Mulder H, Wollheim CB, Eliasson L, Esguerra JLS. Elevated miR-130a/miR130b/miR-152 expression reduces intracellular ATP levels in the pancreatic beta cell. Sci Rep 2017; 7:44986. [PMID: 28332581 PMCID: PMC5362944 DOI: 10.1038/srep44986] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/17/2017] [Indexed: 12/16/2022] Open
Abstract
MicroRNAs have emerged as important players of gene regulation with significant impact in diverse disease processes. In type-2 diabetes, in which impaired insulin secretion is a major factor in disease progression, dysregulated microRNA expression in the insulin-secreting pancreatic beta cell has been widely-implicated. Here, we show that miR-130a-3p, miR-130b-3p, and miR-152-3p levels are elevated in the pancreatic islets of hyperglycaemic donors, corroborating previous findings about their upregulation in the islets of type-2 diabetes model Goto-Kakizaki rats. We demonstrated negative regulatory effects of the three microRNAs on pyruvate dehydrogenase E1 alpha (PDHA1) and on glucokinase (GCK) proteins, which are both involved in ATP production. Consequently, we found both proteins to be downregulated in the Goto-Kakizaki rat islets, while GCK mRNA expression showed reduced trend in the islets of type-2 diabetes donors. Overexpression of any of the three microRNAs in the insulin-secreting INS-1 832/13 cell line resulted in altered dynamics of intracellular ATP/ADP ratio ultimately perturbing fundamental ATP-requiring beta cell processes such as glucose-stimulated insulin secretion, insulin biosynthesis and processing. The data further strengthen the wide-ranging influence of microRNAs in pancreatic beta cell function, and hence their potential as therapeutic targets in type-2 diabetes.
Collapse
Affiliation(s)
- Jones K Ofori
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Vishal A Salunkhe
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Annika Bagge
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Neelanjan Vishnu
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Mototsugu Nagao
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Hindrik Mulder
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Claes B Wollheim
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, 1211, Switzerland
| | - Lena Eliasson
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Jonathan L S Esguerra
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| |
Collapse
|
5
|
Daneshpajooh M, Bacos K, Bysani M, Bagge A, Ottosson Laakso E, Vikman P, Eliasson L, Mulder H, Ling C. HDAC7 is overexpressed in human diabetic islets and impairs insulin secretion in rat islets and clonal beta cells. Diabetologia 2017; 60:116-125. [PMID: 27796421 PMCID: PMC6518079 DOI: 10.1007/s00125-016-4113-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/30/2016] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Pancreatic beta cell dysfunction is a prerequisite for the development of type 2 diabetes. Histone deacetylases (HDACs) may affect pancreatic endocrine function and glucose homeostasis through alterations in gene regulation. Our aim was to investigate the role of HDAC7 in human and rat pancreatic islets and clonal INS-1 beta cells (INS-1 832/13). METHODS To explore the role of HDAC7 in pancreatic islets and clonal beta cells, we used RNA sequencing, mitochondrial functional analyses, microarray techniques, and HDAC inhibitors MC1568 and trichostatin A. RESULTS Using RNA sequencing, we found increased HDAC7 expression in human pancreatic islets from type 2 diabetic compared with non-diabetic donors. HDAC7 expression correlated negatively with insulin secretion in human islets. To mimic the situation in type 2 diabetic islets, we overexpressed Hdac7 in rat islets and clonal beta cells. In both, Hdac7 overexpression resulted in impaired glucose-stimulated insulin secretion. Furthermore, it reduced insulin content, mitochondrial respiration and cellular ATP levels in clonal beta cells. Overexpression of Hdac7 also led to changes in the genome-wide gene expression pattern, including increased expression of Tcf7l2 and decreased expression of gene sets regulating DNA replication and repair as well as nucleotide metabolism. In accordance, Hdac7 overexpression reduced the number of beta cells owing to enhanced apoptosis. Finally, we found that inhibiting HDAC7 activity with pharmacological inhibitors or small interfering RNA-mediated knockdown restored glucose-stimulated insulin secretion in beta cells that were overexpressing Hdac7. CONCLUSIONS/INTERPRETATION Taken together, these results indicate that increased HDAC7 levels caused beta cell dysfunction and may thereby contribute to defects seen in type 2 diabetic islets. Our study supports HDAC7 inhibitors as a therapeutic option for the treatment of type 2 diabetes.
Collapse
Affiliation(s)
- Mahboubeh Daneshpajooh
- Epigenetics and Diabetes Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, CRC, 20502, Malmö, Sweden
| | - Karl Bacos
- Epigenetics and Diabetes Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, CRC, 20502, Malmö, Sweden
| | - Madhusudhan Bysani
- Epigenetics and Diabetes Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, CRC, 20502, Malmö, Sweden
| | - Annika Bagge
- Molecular Metabolism Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Malmö, Sweden
| | - Emilia Ottosson Laakso
- Diabetes and Endocrinology Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Malmö, Sweden
| | - Petter Vikman
- Diabetes and Endocrinology Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Malmö, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Sweden
| | - Hindrik Mulder
- Molecular Metabolism Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Malmö, Sweden
| | - Charlotte Ling
- Epigenetics and Diabetes Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, CRC, 20502, Malmö, Sweden.
| |
Collapse
|
6
|
Sun J, De Marinis Y, Osmark P, Singh P, Bagge A, Valtat B, Vikman P, Spégel P, Mulder H. Discriminative Prediction of A-To-I RNA Editing Events from DNA Sequence. PLoS One 2016; 11:e0164962. [PMID: 27764195 PMCID: PMC5072741 DOI: 10.1371/journal.pone.0164962] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/04/2016] [Indexed: 11/27/2022] Open
Abstract
RNA editing is a post-transcriptional alteration of RNA sequences that, via insertions, deletions or base substitutions, can affect protein structure as well as RNA and protein expression. Recently, it has been suggested that RNA editing may be more frequent than previously thought. A great impediment, however, to a deeper understanding of this process is the paramount sequencing effort that needs to be undertaken to identify RNA editing events. Here, we describe an in silico approach, based on machine learning, that ameliorates this problem. Using 41 nucleotide long DNA sequences, we show that novel A-to-I RNA editing events can be predicted from known A-to-I RNA editing events intra- and interspecies. The validity of the proposed method was verified in an independent experimental dataset. Using our approach, 203 202 putative A-to-I RNA editing events were predicted in the whole human genome. Out of these, 9% were previously reported. The remaining sites require further validation, e.g., by targeted deep sequencing. In conclusion, the approach described here is a useful tool to identify potential A-to-I RNA editing events without the requirement of extensive RNA sequencing.
Collapse
Affiliation(s)
- Jiangming Sun
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
- * E-mail:
| | - Yang De Marinis
- Department of Clinical Sciences in Malmö, Unit of Diabetes and Endocrinology, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Peter Osmark
- Department of Clinical Sciences in Malmö, Unit of Diabetes and Endocrinology, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Pratibha Singh
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Annika Bagge
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Bérengère Valtat
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Petter Vikman
- Department of Clinical Sciences in Malmö, Unit of Diabetes and Endocrinology, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Peter Spégel
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Lund, Sweden
| | - Hindrik Mulder
- Department of Clinical Sciences in Malmö, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| |
Collapse
|
7
|
Bennet H, Mollet IG, Balhuizen A, Medina A, Nagorny C, Bagge A, Fadista J, Ottosson-Laakso E, Vikman P, Dekker-Nitert M, Eliasson L, Wierup N, Artner I, Fex M. Serotonin (5-HT) receptor 2b activation augments glucose-stimulated insulin secretion in human and mouse islets of Langerhans. Diabetologia 2016; 59:744-54. [PMID: 26733006 DOI: 10.1007/s00125-015-3847-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [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: 08/18/2015] [Accepted: 12/04/2015] [Indexed: 12/22/2022]
Abstract
AIMS/HYPOTHESIS The Gq-coupled 5-hydroxytryptamine 2B (5-HT2B) receptor is known to regulate the proliferation of islet beta cells during pregnancy. However, the role of serotonin in the control of insulin release is still controversial. The aim of the present study was to explore the role of the 5-HT2B receptor in the regulation of insulin secretion in mouse and human islets, as well as in clonal INS-1(832/13) cells. METHODS Expression of HTR2B mRNA and 5-HT2B protein was examined with quantitative real-time PCR, RNA sequencing and immunohistochemistry. α-Methyl serotonin maleate salt (AMS), a serotonin receptor agonist, was employed for robust 5-HT2B receptor activation. Htr2b was silenced with small interfering RNA in INS-1(832/13) cells. Insulin secretion, Ca(2+) response and oxygen consumption rate were determined. RESULTS Immunohistochemistry revealed that 5-HT2B is expressed in human and mouse islet beta cells. Activation of 5-HT2B receptors by AMS enhanced glucose-stimulated insulin secretion (GSIS) in human and mouse islets as well as in INS-1(832/13) cells. Silencing Htr2b in INS-1(832/13) cells led to a 30% reduction in GSIS. 5-HT2B receptor activation produced robust, regular and sustained Ca(2+) oscillations in mouse islets with an increase in both peak distance (period) and time in the active phase as compared with control. Enhanced insulin secretion and Ca(2+) changes induced by AMS coincided with an increase in oxygen consumption in INS-1(832/13) cells. CONCLUSIONS/INTERPRETATION Activation of 5-HT2B receptors stimulates GSIS in beta cells by triggering downstream changes in cellular Ca(2+) flux that enhance mitochondrial metabolism. Our findings suggest that serotonin and the 5-HT2B receptor stimulate insulin release.
Collapse
Affiliation(s)
- Hedvig Bennet
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit of Diabetes and Celiac disease, Clinical Research Centre, Jan Waldenströms gata 35, Clinical Research Centre House 91:10, Skåne University Hospital Malmö, SE-20502, Malmö, Sweden.
| | - Inês G Mollet
- Lund University Diabetes Centre, Islet Cell Exocytosis, Malmö, Sweden
| | - Alexander Balhuizen
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit of Diabetes and Celiac disease, Clinical Research Centre, Jan Waldenströms gata 35, Clinical Research Centre House 91:10, Skåne University Hospital Malmö, SE-20502, Malmö, Sweden
| | - Anya Medina
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit of Diabetes and Celiac disease, Clinical Research Centre, Jan Waldenströms gata 35, Clinical Research Centre House 91:10, Skåne University Hospital Malmö, SE-20502, Malmö, Sweden
| | - Cecilia Nagorny
- Lund University Diabetes Centre, Molecular Metabolism, Malmö, Sweden
| | - Annika Bagge
- Lund University Diabetes Centre, Molecular Metabolism, Malmö, Sweden
| | - Joao Fadista
- Lund University Diabetes Centre, Diabetes and Endocrinology, Malmö, Sweden
| | | | - Petter Vikman
- Lund University Diabetes Centre, Diabetes and Endocrinology, Malmö, Sweden
| | - Marloes Dekker-Nitert
- Lund University Diabetes Centre, Diabetes and Endocrinology, Malmö, Sweden
- Royal Brisbane Clinical School, UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
| | - Lena Eliasson
- Lund University Diabetes Centre, Islet Cell Exocytosis, Malmö, Sweden
| | - Nils Wierup
- Lund University Diabetes Centre, Neuroendocrine Cell Biology, Malmö, Sweden
| | - Isabella Artner
- Lund University Diabetes Centre, Stem Cell Center, Biomedical Centre (BMC), Lund, Sweden
| | - Malin Fex
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit of Diabetes and Celiac disease, Clinical Research Centre, Jan Waldenströms gata 35, Clinical Research Centre House 91:10, Skåne University Hospital Malmö, SE-20502, Malmö, Sweden
| |
Collapse
|
8
|
Andersson LE, Valtat B, Bagge A, Sharoyko VV, Nicholls DG, Ravassard P, Scharfmann R, Spégel P, Mulder H. Characterization of stimulus-secretion coupling in the human pancreatic EndoC-βH1 beta cell line. PLoS One 2015; 10:e0120879. [PMID: 25803449 PMCID: PMC4372368 DOI: 10.1371/journal.pone.0120879] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 02/09/2015] [Indexed: 02/07/2023] Open
Abstract
Aims/Hypothesis Studies on beta cell metabolism are often conducted in rodent beta cell lines due to the lack of stable human beta cell lines. Recently, a human cell line, EndoC-βH1, was generated. Here we investigate stimulus-secretion coupling in this cell line, and compare it with that in the rat beta cell line, INS-1 832/13, and human islets. Methods Cells were exposed to glucose and pyruvate. Insulin secretion and content (radioimmunoassay), gene expression (Gene Chip array), metabolite levels (GC/MS), respiration (Seahorse XF24 Extracellular Flux Analyzer), glucose utilization (radiometric), lactate release (enzymatic colorimetric), ATP levels (enzymatic bioluminescence) and plasma membrane potential and cytoplasmic Ca2+ responses (microfluorometry) were measured. Metabolite levels, respiration and insulin secretion were examined in human islets. Results Glucose increased insulin release, glucose utilization, raised ATP production and respiratory rates in both lines, and pyruvate increased insulin secretion and respiration. EndoC-βH1 cells exhibited higher insulin secretion, while plasma membrane depolarization was attenuated, and neither glucose nor pyruvate induced oscillations in intracellular calcium concentration or plasma membrane potential. Metabolite profiling revealed that glycolytic and TCA-cycle intermediate levels increased in response to glucose in both cell lines, but responses were weaker in EndoC-βH1 cells, similar to those observed in human islets. Respiration in EndoC-βH1 cells was more similar to that in human islets than in INS-1 832/13 cells. Conclusions/Interpretation Functions associated with early stimulus-secretion coupling, with the exception of plasma membrane potential and Ca2+ oscillations, were similar in the two cell lines; insulin secretion, respiration and metabolite responses were similar in EndoC-βH1 cells and human islets. While both cell lines are suitable in vitro models, with the caveat of replicating key findings in isolated islets, EndoC-βH1 cells have the advantage of carrying the human genome, allowing studies of human genetic variants, epigenetics and regulatory RNA molecules.
Collapse
Affiliation(s)
- Lotta E. Andersson
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
- * E-mail:
| | - Bérengère Valtat
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Annika Bagge
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Vladimir V. Sharoyko
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - David G. Nicholls
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
- Buck Institute for Research on Aging, Novato, California, United States of America
| | - Philippe Ravassard
- Université Pierre et Marie Curie-Paris 6, Biotechnology and Biotherapy Team, Centre de Recherche de I’Institut du Cerveau et de la Moelle épiniére (CRICM), UMRS 975, Paris, France
| | - Raphael Scharfmann
- INSERM U1016, Cochin Institute, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Faculty Cochin, Paris, France
| | - Peter Spégel
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| | - Hindrik Mulder
- Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, CRC, Malmö, Sweden
| |
Collapse
|
9
|
Howden R, Heimer H, Cividanes S, Zacherle E, Arthur S, Bagge A, Huet Y. Differential Cardiac Responses to Prolonged Hyperoxia vs. Hypoxia Exposures (LB795). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.lb795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Heidi Heimer
- Kinesiology UNC CharlotteCharlotteNCUnited States
| | | | | | - Susan Arthur
- Kinesiology UNC CharlotteCharlotteNCUnited States
| | - Annika Bagge
- Department of Clinical Sciences Lund University Diabetes CentreMalmoSweden
| | - Yvette Huet
- Kinesiology UNC CharlotteCharlotteNCUnited States
| |
Collapse
|
10
|
Abstract
Downregulation of proteins involved in the -exocytotic machinery has been implicated in the impairment of normal β-cell function in response to high glucose levels. Syntaxin-1a -(Stx-1a) is one of two t-SNAREs involved in insulin exocytosis and decreased expression of Stx-1a protein impairs glucose-stimulated insulin secretion (GSIS) in isolated rat pancreatic islets. In diabetic patients Stx-1a protein levels are reduced, but the mechanism of this suppression is unknown.MicroRNAs are small noncoding RNAs, which are important regulators of gene-expression at the post transcriptional level, partially binding to the 3'UTRs of their target gene transcripts either mediating transcript degradation or inhibiting translation. We have recently shown that miR-29a is upregulated in response to elevated glucose levels in β-cells and is involved in mediating the negative effect of high glucose levels on GSIS. Stx-1a has a predicted target site of miR-29a present in its 3' untranslated region. The objective of this study was to evaluate whether miR-29a targets Stx-1a directly to decrease mRNA and/or protein levels in response to glucose. Stx-1a mRNA and protein levels decreased in β-cells treated with increased glucose levels. Overexpression of miR-29a decreased Stx-1a mRNA and protein levels. Furthermore, miR-29a decreases the response of a luciferase reporter construct containing the predicted target site normally present in the Stx-1a gene. When 2 nucleotides are mutated in this target site, responsiveness to miR-29a disappears, confirming miR-29a binding to this sequence. Collectively, these data implicate miR-29a as a mediator of glucose-induced downregulation of Stx-1a in β-cells.
Collapse
Affiliation(s)
- A Bagge
- Department of Science, Roskilde University, Roskilde, Denmark
| | | | | |
Collapse
|
11
|
Bagge A, Clausen TR, Larsen S, Ladefoged M, Rosenstierne MW, Larsen L, Vang O, Nielsen JH, Dalgaard LT. MicroRNA-29a is up-regulated in beta-cells by glucose and decreases glucose-stimulated insulin secretion. Biochem Biophys Res Commun 2012; 426:266-72. [DOI: 10.1016/j.bbrc.2012.08.082] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 01/05/2023]
|
12
|
Blazek RD, Bagge A, Valtonen ET. Monogenean assemblages and the apparent transmission capability of monogeneans between related fish species: an experimental study. Parasitol Res 2008; 102:1359-66. [DOI: 10.1007/s00436-008-0918-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Accepted: 01/30/2008] [Indexed: 11/29/2022]
|