1
|
Richartz N, Pietka W, Yadav A, Bostad M, Bhagwat S, Naderi S, Naderi EH, Stokke T, Ruud E, Blomhoff HK. N-acetyl cysteine turns EPAC activators into potent killers of acute lymphoblastic leukemia cells. J Biol Chem 2024; 300:105509. [PMID: 38042493 PMCID: PMC10772734 DOI: 10.1016/j.jbc.2023.105509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 12/04/2023] Open
Abstract
Today, the majority of patients with pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL, hereafter ALL) survive their disease, but many of the survivors suffer from life-limiting late effects of the treatment. ALL develops in the bone marrow, where the cells are exposed to cAMP-generating prostaglandin E2. We have previously identified the cAMP signaling pathway as a putative target for improved efficacy of ALL treatment, based on the ability of cAMP signaling to reduce apoptosis induced by DNA damaging agents. In the present study, we have identified the antioxidant N-acetyl cysteine (NAC) as a powerful modifier of critical events downstream of the cell-permeable cAMP analog 8-(4-chlorophenylthio) adenosine-3', 5'- cyclic monophosphate (8-CPT). Accordingly, we found NAC to turn 8-CPT into a potent killer of ALL cells in vitro both in the presence and absence of DNA damaging treatment. Furthermore, we revealed that NAC in combination with 8-CPT is able to delay the progression of ALL in a xenograft model in NOD-scid IL2Rγnull mice. NAC was shown to rely on the ability of 8-CPT to activate the guanine-nucleotide exchange factor EPAC, and we demonstrated that the ALL cells are killed by apoptosis involving sustained elevated levels of calcium imposed by the combination of the two drugs. Taken together, we propose that 8-CPT in the presence of NAC might be utilized as a novel strategy for treating pediatric ALL patients, and that this powerful combination might be exploited to enhance the therapeutic index of current ALL targeting therapies.
Collapse
Affiliation(s)
- Nina Richartz
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Wojciech Pietka
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Ajay Yadav
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Monica Bostad
- Department of Core Facilities, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sampada Bhagwat
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Soheil Naderi
- Division of Laboratory Medicine, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Elin Hallan Naderi
- Section of Head and Neck Oncology, Department of Oncology, Oslo University Hospital, Oslo, Norway
| | - Trond Stokke
- Department of Core Facilities, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Ellen Ruud
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Heidi Kiil Blomhoff
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
| |
Collapse
|
2
|
Kondegowda NG, Filipowska J, Do JS, Leon-Rivera N, Li R, Hampton R, Ogyaadu S, Levister C, Penninger JM, Reijonen H, Levy CJ, Vasavada RC. RANKL/RANK is required for cytokine-induced beta cell death; osteoprotegerin, a RANKL inhibitor, reverses rodent type 1 diabetes. SCIENCE ADVANCES 2023; 9:eadf5238. [PMID: 37910614 PMCID: PMC10619938 DOI: 10.1126/sciadv.adf5238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 09/29/2023] [Indexed: 11/03/2023]
Abstract
Treatment for type 1 diabetes (T1D) requires stimulation of functional β cell regeneration and survival under stress. Previously, we showed that inhibition of the RANKL/RANK [receptor activator of nuclear factor kappa Β (NF-κB) ligand] pathway, by osteoprotegerin and the anti-osteoporotic drug denosumab, induces rodent and human β cell proliferation. We demonstrate that the RANK pathway mediates cytokine-induced rodent and human β cell death through RANK-TRAF6 interaction and induction of NF-κB activation. Osteoprotegerin and denosumab protected β cells against this cytotoxicity. In human immune cells, osteoprotegerin and denosumab reduce proinflammatory cytokines in activated T-cells by inhibiting RANKL-induced activation of monocytes. In vivo, osteoprotegerin reversed recent-onset T1D in nonobese diabetic/Ltj mice, reduced insulitis, improved glucose homeostasis, and increased plasma insulin, β cell proliferation, and mass in these mice. Serum from T1D subjects induced human β cell death and dysfunction, but not α cell death. Osteoprotegerin and denosumab reduced T1D serum-induced β cell cytotoxicity and dysfunction. Inhibiting RANKL/RANK could have therapeutic potential.
Collapse
Affiliation(s)
- Nagesha Guthalu Kondegowda
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Joanna Filipowska
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jeong-su Do
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Nancy Leon-Rivera
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Rosemary Li
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rollie Hampton
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Selassie Ogyaadu
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Division of Endocrinology and Bone Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Camilla Levister
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Division of Endocrinology and Bone Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Josef M. Penninger
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria
- Department of Medical Genetics, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Helena Reijonen
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Carol J. Levy
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Division of Endocrinology and Bone Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rupangi C. Vasavada
- Department of Translational Research and Cellular Therapeutics, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| |
Collapse
|
3
|
Benson JC, Trebak M. Too much of a good thing: The case of SOCE in cellular apoptosis. Cell Calcium 2023; 111:102716. [PMID: 36931194 PMCID: PMC10481469 DOI: 10.1016/j.ceca.2023.102716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/13/2023]
Abstract
Intracellular calcium (Ca2+) is an essential second messenger in eukaryotic cells regulating numerous cellular functions such as contraction, secretion, immunity, growth, and metabolism. Ca2+ signaling is also a key signal transducer in the intrinsic apoptosis pathway. The store-operated Ca2+ entry pathway (SOCE) is ubiquitously expressed in eukaryotic cells, and is the primary Ca2+ influx pathway in non-excitable cells. SOCE is mediated by the endoplasmic reticulum Ca2+ sensing STIM proteins, and the plasma membrane Ca2+-selective Orai channels. A growing number of studies have implicated SOCE in regulating cell death primarily via the intrinsic apoptotic pathway in a variety of tissues and in response to physiological stressors such as traumatic brain injury, ischemia reperfusion injury, sepsis, and alcohol toxicity. Notably, the literature points to excessive cytosolic Ca2+ influx through SOCE in vulnerable cells as a key factor tipping the balance towards cellular apoptosis. While the literature primarily addresses the functions of STIM1 and Orai1, STIM2, Orai2 and Orai3 are also emerging as potential regulators of cell death. Here, we review the functions of STIM and Orai proteins in regulating cell death and the implications of this regulation to human pathologies.
Collapse
Affiliation(s)
- J Cory Benson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 1526, USA; Vascular Medicine Institute, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 1526, USA; Department of Cellular and Molecular Physiology, Graduate Program, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Mohamed Trebak
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 1526, USA; Vascular Medicine Institute, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 1526, USA; UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 1526, USA.
| |
Collapse
|
4
|
Recio-López P, Valladolid-Acebes I, Hadwiger P, Hossbach M, Krampert M, Prata C, Berggren PO, Juntti-Berggren L. Treatment of the metabolic syndrome by siRNA targeting apolipoprotein CIII. Biofactors 2023; 49:153-172. [PMID: 36039858 DOI: 10.1002/biof.1885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/05/2022] [Indexed: 11/06/2022]
Abstract
Apolipoprotein CIII (apoCIII) is increased in obesity-induced insulin resistance and type-2 diabetes. Emerging evidences support the advantages of small interfering RNAs (siRNAs) to target disease-causing genes. The aim of this study was to develop siRNAs for in vivo silencing of apoCIII and investigate if this results in metabolic improvements comparable to what we have seen using antisense oligonucelotides against apoCIII. Twenty-four siRNAs were synthesized and tested in a dual luciferase reporter assay. The eight best were selected, based on knockdown at 20 nM, and of these, two were selected based on IC50 values. In vivo experiments were performed in ob/ob mice, an obese animal model for diabetes. To determine the dose-dependency, efficacy, duration of effect and therapeutic dose we used a short protocol giving the apoCIII-siRNA mix for three days. To evaluate long-term metabolic effects mice were treated for three days, every second week for eight weeks. The siRNA mix effectively and selectively reduced expression of apoCIII in liver in vivo. Treatment had to be repeated every two weeks to maintain a suppression of apoCIII. The reduction of apoCIII resulted in increased LPL activity, lower triglycerides, reduced liver fat, ceased weight gain, enhanced insulin sensitivity, and improved glucose homeostasis. No off-target or side effects were observed during the eight-week treatment period. These results suggest that in vivo silencing of apoCIII with siRNA, is a promising approach with the potential to be used in the battle against obesity-induced metabolic disorders.
Collapse
Affiliation(s)
- Patricia Recio-López
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm, Sweden
| | - Ismael Valladolid-Acebes
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm, Sweden
| | | | | | | | | | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm, Sweden
| | - Lisa Juntti-Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1, Stockholm, Sweden
| |
Collapse
|
5
|
Kittl M, Winklmayr M, Preishuber-Pflügl J, Strobl V, Gaisberger M, Ritter M, Jakab M. Low pH Attenuates Apoptosis by Suppressing the Volume-Sensitive Outwardly Rectifying (VSOR) Chloride Current in Chondrocytes. Front Cell Dev Biol 2022; 9:804105. [PMID: 35186954 PMCID: PMC8847443 DOI: 10.3389/fcell.2021.804105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/31/2021] [Indexed: 11/25/2022] Open
Abstract
In a variety of physiological and pathophysiological conditions, cells are exposed to acidic environments. Severe synovial fluid acidification also occurs in a progressive state of osteoarthritis (OA) affecting articular chondrocytes. In prior studies extracellular acidification has been shown to protect cells from apoptosis but the underlying mechanisms remain elusive. In the present study, we demonstrate that the inhibition of Cl− currents plays a significant role in the antiapoptotic effect of acidification in human articular chondrocytes. Drug-induced apoptosis was analyzed after exposure to staurosporine by caspase 3/7 activity and by annexin-V/7-actinomycin D (7-AAD) staining, followed by flow cytometry. Cell viability was assessed by resazurin, CellTiter-Glo and CellTiter-Fluor assays. Cl− currents and the mean cell volume were determined using the whole cell patch clamp technique and the Coulter method, respectively. The results reveal that in C28/I2 cells extracellular acidification decreases caspase 3/7 activity, enhances cell viability following staurosporine treatment and gradually deactivates the volume-sensitive outwardly rectifying (VSOR) Cl− current. Furthermore, the regulatory volume decrease (RVD) as well as the apoptotic volume decrease (ADV), which represents an early event during apoptosis, were absent under acidic conditions after hypotonicity-induced cell swelling and staurosporine-induced apoptosis, respectively. Like acidosis, the VSOR Cl− current inhibitor DIDS rescued chondrocytes from apoptotic cell death and suppressed AVD after induction of apoptosis with staurosporine. Similar to acidosis and DIDS, the VSOR channel blockers NPPB, niflumic acid (NFA) and DCPIB attenuated the staurosporine-induced AVD. NPPB and NFA also suppressed staurosporine-induced caspase 3/7 activation, while DCPIB and Tamoxifen showed cytotoxic effects per se. From these data, we conclude that the deactivation of VSOR Cl− currents impairs cell volume regulation under acidic conditions, which is likely to play an important role in the survivability of human articular chondrocytes.
Collapse
Affiliation(s)
- Michael Kittl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- *Correspondence: Michael Kittl,
| | - Martina Winklmayr
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
| | - Julia Preishuber-Pflügl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Victoria Strobl
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Martin Gaisberger
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
| | - Markus Ritter
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology, Pathophysiology and Biophysics—Nuremberg, Paracelsus Medical University, Nuremberg, Germany
| | - Martin Jakab
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology—Salzburg, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Salzburg, Austria
| |
Collapse
|
6
|
Valladolid-Acebes I, Berggren PO, Juntti-Berggren L. Apolipoprotein CIII Is an Important Piece in the Type-1 Diabetes Jigsaw Puzzle. Int J Mol Sci 2021; 22:ijms22020932. [PMID: 33477763 PMCID: PMC7832341 DOI: 10.3390/ijms22020932] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/09/2021] [Accepted: 01/14/2021] [Indexed: 12/05/2022] Open
Abstract
It is well known that type-2 diabetes mellitus (T2D) is increasing worldwide, but also the autoimmune form, type-1 diabetes (T1D), is affecting more people. The latest estimation from the International Diabetes Federation (IDF) is that 1.1 million children and adolescents below 20 years of age have T1D. At present, we have no primary, secondary or tertiary prevention or treatment available, although many efforts testing different strategies have been made. This review is based on the findings that apolipoprotein CIII (apoCIII) is increased in T1D and that in vitro studies revealed that healthy β-cells exposed to apoCIII became apoptotic, together with the observation that humans with higher levels of the apolipoprotein, due to mutations in the gene, are more susceptible to developing T1D. We have summarized what is known about apoCIII in relation to inflammation and autoimmunity in in vitro and in vivo studies of T1D. The aim is to highlight the need for exploring this field as we still are only seeing the top of the iceberg.
Collapse
|
7
|
Aguilar-Recarte D, Palomer X, Vázquez-Carrera M. Uncovering the role of apolipoprotein C-III in insulin resistance. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS 2020; 33:108-115. [PMID: 33303217 DOI: 10.1016/j.arteri.2020.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 11/26/2022]
Abstract
Apolipoprotein C-III (apoC-III) is a small protein that is predominantly synthesized in the liver and mainly resides at the surface of triglyceride-rich lipoproteins. Its expression is upregulated by glucose and reduced by insulin, with enhanced apoC-III promoting hypertriglyceridemia and inflammation in vascular cells. The protein is also elevated in patients with diabetes, suggesting that enhanced apoC-III levels might contribute to the development of type 2 diabetes mellitus. The present review focuses on the key mechanisms by which apoC-III could promote type 2 diabetes mellitus, including exacerbation of insulin resistance in skeletal muscle, activation of β-cell apoptosis, promotion of weight gain through its effects on white adipose tissue and hypothalamus, and attenuation of the beneficial effects of high-density lipoproteins on glucose metabolism. Therapeutic strategies aimed at reducing apoC-III levels may not only reduce hypertriglyceridemia but also might improve insulin resistance, thus delaying the development of type 2 diabetes mellitus.
Collapse
Affiliation(s)
- David Aguilar-Recarte
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Spain; Research Institute-Hospital Sant Joan de Déu, Barcelona, Spain
| | - Xavier Palomer
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Spain; Research Institute-Hospital Sant Joan de Déu, Barcelona, Spain
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Spain; Research Institute-Hospital Sant Joan de Déu, Barcelona, Spain.
| |
Collapse
|
8
|
Serum miR-17 levels are downregulated in obese, African American women with elevated HbA1c. J Diabetes Metab Disord 2019; 18:173-179. [PMID: 31275888 DOI: 10.1007/s40200-019-00404-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 04/12/2019] [Indexed: 12/17/2022]
Abstract
Purpose Type 2 diabetes is heterogeneous disease characterized by several conditions including hyperglycemia. It is estimated that over 350 million people worldwide are suffering from type 2 diabetes and this number is expected to rise. According to the CDC, African Americans were observed to have a 40% higher incidence of diabetes compared to European Americans. Epigenetic modulating mechanisms such as microRNAs (miRNAs), have recently been established as a massive regulatory machine in metabolic syndrome, obesity and type 2 diabetes. In the present study, we aimed to investigate the serum levels of circulating miRNA 17 (miR-17) of obese, African American women with elevated HbA1c. Methods We investigated miR-17 serum levels using qPCR. Then we used Pairwise Pearson Correlation Test to determine the relationship between clinical metabolic parameters and miR-17 serum levels. Results The results indicated that participants with elevated HbA1c exhibited a down regulation of serum miR-17 levels compared to participants with normal HbA1c. MiR-17 was also correlated with serum calcium in participants with normal HbA1c. Conclusions The results suggest that serum miR-17 is involved in the regulation of glucose and calcium homeostasis, which may contribute to the development of type 2 diabetes.
Collapse
|
9
|
Szczoczarz A, Marchwińska A, Dyś A, Boblewski K, Lehmann A, Lewko B, Rybczyńska A. Verapamil prevents the effect of calcium-sensing receptor activation on the blood glucose and insulin levels in rats. Pharmacol Rep 2019; 71:478-484. [PMID: 31003161 DOI: 10.1016/j.pharep.2019.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/14/2018] [Accepted: 01/04/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND The Ca2+ triggered insulin exocytosis in β cells of the pancreatic islets may be the result of Ca2+ influx through L-type voltage dependent calcium channels (VDCC) localized in the plasma membrane, as well as of liberation of Ca2+ from intracellular storages, induced by activation of the calcium receptor (CaR) coupled with the PLC enzyme present in the pancreatic islets. The present study was designated to determine, in in vivo experiments, the effects of CaR activation by R-568 and inhibition of the receptor by NPS 2143 on the plasma glucose and insulin levels in the presence of verapamil, a calcium channel blocker. METHODS Wistar rats, after fasting for 14 h before the experiment, were anesthetized with inactin and loaded ip with 1 g/kg glucose. RESULTS In comparison to the control group, the verapamil-induced blockade of the calcium channels in glucose loaded animals increased the blood glucose level and decreased the insulin level, whereas CaR activation with R-568 induced opposite effects. However, in the presence of verapamil, R-568 did not change the concentration of glucose or insulin versus the control animals. Verapamil infusion did not alter elevated glucose concentration in the NPS 2143 animals. At the same time, verapamil reduced the plasma insulin level and potentiated the drop of insulin concentration induced by NPS 2143. CONCLUSION The observations suggest that under the in vivo conditions, calcium channel blockade may prevent changes in the blood glucose and insulin concentrations induced by the CaR activation.
Collapse
Affiliation(s)
- Anna Szczoczarz
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
| | - Aleksandra Marchwińska
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
| | - Aleksandra Dyś
- Department of Laboratory Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Konrad Boblewski
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
| | - Artur Lehmann
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
| | - Barbara Lewko
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland
| | - Apolonia Rybczyńska
- Department of Pathophysiology, Faculty of Pharmacy, Medical University of Gdańsk, Gdańsk, Poland.
| |
Collapse
|
10
|
Christopoulou E, Tsimihodimos V, Filippatos T, Elisaf M. Apolipoprotein CIII and diabetes. Is there a link? Diabetes Metab Res Rev 2019; 35:e3118. [PMID: 30557902 DOI: 10.1002/dmrr.3118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/09/2018] [Accepted: 12/11/2018] [Indexed: 12/24/2022]
Abstract
Apolipoprotein CIII (ApoCIII), a small protein that resides on the surface of lipoprotein particles, is a key regulator of triglyceride metabolism. The inhibition of lipoprotein lipase (LPL), the increased assembly and secretion of very low-density lipoproteins (VLDL) and the decreased reuptake of triglyceride-rich lipoproteins (TRLs) by the liver are mechanisms associating elevated serum ApoCIII levels and hypertriglyceridemia. ApoCIII concentration is high in individuals with diabetes mellitus, indicating a possible positive correlation with impairment of glucose metabolism. The aim of this review (based on a Pubmed search until August 2018) is to present the possible mechanisms linking ApoCIII and deterioration of carbohydrate homeostasis. ApoCIII enhances pancreatic β-cells apoptosis via an increase of the cytoplasmic Ca2+ levels in the insulin-producing cells. In addition, overexpression of ApoCIII enhances non-alcoholic fatty liver disease and exacerbates inflammatory pathways in skeletal muscles, affecting insulin signalling and thereby inducing insulin resistance. Moreover, recent studies reveal a possible mechanism of body weight increase and glucose production through a potential ApoCIII-induced LPL inhibition in the hypothalamus. Also, the presence of ApoCIII on the surface of high-density lipoprotein particles is associated with impairment of their antiglycemic and atheroprotective properties. Modulating ApoCIII may be a potent therapeutic approach to manage hypertriglyceridemia and improve carbohydrate metabolism.
Collapse
Affiliation(s)
- Eliza Christopoulou
- Department of Internal Medicine, School of Medicine, University of Ioannina, Ioannina, Greece
| | - Vasilios Tsimihodimos
- Department of Internal Medicine, School of Medicine, University of Ioannina, Ioannina, Greece
| | - Theodosios Filippatos
- Department of Internal Medicine, School of Medicine, University of Crete, Heraklion, Greece
| | - Moses Elisaf
- Department of Internal Medicine, School of Medicine, University of Ioannina, Ioannina, Greece
| |
Collapse
|
11
|
Neither polyphenol-rich red wine nor fenofibrate affects the onset of type-1 diabetes mellitus in the BB rat. Lab Anim Res 2018; 34:126-131. [PMID: 30310409 PMCID: PMC6170222 DOI: 10.5625/lar.2018.34.3.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 11/21/2022] Open
Abstract
Serum levels of the pro-inflammatory apolipoprotein CIII (apoCIII) are increased in type-1 diabetic (T1D) patients and when β-cells are exposed to apoCIII they undergo apoptosis, which can be prevented by an antibody against apoCIII. We have previously investigated the BB rat, an animal model that develops a human-like T1D at the age of around 60 days, and found that apoCIII was also increased in sera from pre-diabetic rats and this promoted β-cell death. Lowering apoCIII with an oligonucleotide antisense during a phase of the pre-diabetic period prolonged the time to onset of T1D. In order to find other ways to lower apoCIII we in this study tested non-alcoholic red wine with medium and high concentrations of polyphenols and the lipid-lowering drug, fenofibrate, both reported to decrease the expression of apoCIII by activating peroxisome proliferator-activated receptors. Pre-diabetic BB-rats were treated orally for one month prior to the expected onset of diabetes with the two different wines or fenofibrate. None of the treatments prevented or prolonged the time to onset of diabetes and the expression of apoCIII was unaffected in this animal model for T1D. However, it must be emphasized that this does not exclude that other species can show a response to these substances.
Collapse
|
12
|
Wang Y, Tang S, Harvey KE, Salyer AE, Li TA, Rantz EK, Lill MA, Hockerman GH. Molecular Determinants of the Differential Modulation of Ca v1.2 and Ca v1.3 by Nifedipine and FPL 64176. Mol Pharmacol 2018; 94:973-983. [PMID: 29980657 PMCID: PMC11033928 DOI: 10.1124/mol.118.112441] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 06/28/2018] [Indexed: 11/22/2022] Open
Abstract
Nifedipine and FPL 64176 (FPL), which block and potentiate L-type voltage-gated Ca2+ channels, respectively, modulate Cav1.2 more potently than Cav1.3. To identify potential strategies for developing subtype-selective inhibitors, we investigated the role of divergent amino acid residues in transmembrane domains IIIS5 and the extracellular IIIS5-3P loop region in modulation of these channels by nifedipine and FPL. Insertion of the extracellular IIIS5-3P loop from Cav1.2 into Cav1.3 (Cav1.3+) reduced the IC50 of nifedipine from 289 to 101 nM, and substitution of S1100 with an A residue, as in Cav1.2, accounted for this difference. Substituting M1030 in IIIS5 to V in Cav1.3+ (Cav1.3+V) further reduced the IC50 of nifedipine to 42 nM. FPL increased current amplitude with an EC50 of 854 nM in Cav1.3, 103 nM in Cav1.2, and 99 nM in Cav1.3+V. In contrast to nifedipine block, substitution of M1030 to V in Cav1.3 had no effect on potency of FPL potentiation of current amplitude, but slowed deactivation in the presence and absence of 10 μM FPL. FPL had no effect on deactivation of Cav1.3/dihydropyridine-insensitive (DHPi), a channel with very low sensitivity to nifedipine block (IC50 ∼93 μM), but did shift the voltage-dependence of activation by ∼-10 mV. We conclude that the M/V variation in IIIS5 and the S/A variation in the IIIS5-3P loop of Cav1.2 and Cav1.3 largely determine the difference in nifedipine potency between these two channels, but the difference in FPL potency is determined by divergent amino acids in the IIIS5-3P loop.
Collapse
Affiliation(s)
- Yuchen Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Shiqi Tang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Kyle E Harvey
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Amy E Salyer
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - T August Li
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Emily K Rantz
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Markus A Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| | - Gregory H Hockerman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, Indiana
| |
Collapse
|
13
|
Rorsman P, Ashcroft FM. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev 2018; 98:117-214. [PMID: 29212789 PMCID: PMC5866358 DOI: 10.1152/physrev.00008.2017] [Citation(s) in RCA: 424] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/30/2017] [Accepted: 06/18/2017] [Indexed: 12/14/2022] Open
Abstract
The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity, and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM.
Collapse
Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frances M Ashcroft
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
14
|
Wright CM, Moorin RE, Chowdhury EK, Stricker BH, Reid CM, Saunders CM, Hughes JD. Calcium channel blockers and breast cancer incidence: An updated systematic review and meta-analysis of the evidence. Cancer Epidemiol 2017; 50:113-124. [PMID: 28866282 DOI: 10.1016/j.canep.2017.08.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/15/2017] [Accepted: 08/19/2017] [Indexed: 12/18/2022]
Abstract
Controversy exists regarding the potential association between taking calcium channel blockers (CCBs) and the development of breast cancer. As a positive association would have important public health implications due to the widespread use of CCBs, this study aimed to incorporate new evidence to determine whether an association is likely to exist. We searched MEDLINE, EMBASE and the Cochrane Library to 28 June 2016 for relevant literature. References and citing articles were checked and authors contacted as necessary. Two authors independently selected articles and extracted data. Twenty-nine studies were reviewed; 26 were non-randomised studies (NRS). Meta-analysis of study data where adjustment for 'confounding by indication' was judged to be present suggests that an association, if any, is likely to be modest in magnitude (pooled odds/risk ratio 1.09 (95% confidence interval (CI) 1.03-1.15, I2=0%, 8 sub-studies; pooled hazard ratio 0.99 (95% CI 0.94-1.03, I2=35%, 9 sub-studies)). There are credible study data showing an increased relative risk with long-term use of CCBs, but the results of our meta-analysis and of meta-regression of log relative risk against minimum follow-up time are mixed. The current summative evidence does not support a clear association between taking CCBs and developing breast cancer. However, uncertainty remains, especially for long-term use and any association might not be uniform between different populations and/or breast cancer sub-types. We thus recommend further NRS in settings where CCB use is highly prevalent and population-based cancer, prescription and health-registries exist, to resolve this continuing uncertainty. PROSPERO, CRD42015026712.
Collapse
Affiliation(s)
- Cameron M Wright
- Health Systems and Health Economics, School of Public Health, Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, Western Australia, 6845, Australia; School of Pharmacy, Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, Western Australia, 6845, Australia; School of Medicine, University of Tasmania, Private Bag 26, Sandy Bay, Tasmania, 7001, Australia.
| | - Rachael E Moorin
- Health Systems and Health Economics, School of Public Health, Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, Western Australia, 6845, Australia; Centre for Health Services Research, School of Population and Global Health, Faculty of Medicine, Dentistry and Health Sciences, 35 Stirling Highway, University of Western Australia, Crawley, Perth, Western Australia, 6009, Australia.
| | - Enayet K Chowdhury
- Centre for Cardiovascular Research and Education in Therapeutics, Monash University, Melbourne, Victoria, 3800, Australia.
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus MC: University Medical Centre, Rotterdam, 3015, Netherlands.
| | - Christopher M Reid
- School of Pharmacy, Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, Western Australia, 6845, Australia; School of Public Health, Faculty of Health Sciences, GPO Box 1987, Curtin University, Perth, Western Australia, 6845, Australia.
| | - Christobel M Saunders
- School of Surgery, Faculty of Medicine, Dentistry and Health Sciences, 35 Stirling Highway, University of Western Australia, Perth, Western Australia, 6009, Australia.
| | - Jeffery D Hughes
- School of Pharmacy, Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, Western Australia, 6845, Australia.
| |
Collapse
|
15
|
Abstract
PURPOSE OF REVIEW Type-1 and type-2 diabetes are diseases with an increasing number of patients and a complex, multifactorial pathogenesis. Apolipoprotein (apo) CIII is increased in both types of diabetes and interventions preventing the increase have effects on the development of diabetes. RECENT FINDINGS ApoCIII affects intracellular Ca-handling by activating voltage-gated Ca-channels. ApoCIII is produced within the pancreatic islets and it increases in parallel with the development of insulin resistance and type-2 diabetes. Preventing the increase maintains a normal glucose tolerance as well as Ca-handling and no signs of inflammation can be seen in islets wherein the augmented local production of the apolipoprotein is absent. SUMMARY ApoCIII has been found to interfere with both function and survival of the β-cell and thereby promote the development of diabetes. Increased levels of this apolipoprotein affects intracellular Ca-handling and insulin sensitivity, which finally results in impaired glucose homeostasis and diabetes. Interestingly, in a type-1 diabetes rat model lowering of apoCIII delays onset of diabetes. In type-2 diabetes insulin resistance within the pancreatic islets leads to a local increase in apoCIII that promotes inflammation and β-cell dysfunction. Hence, targeting apoCIII may constitute a novel pharmacological strategy to treat both type-1 and type-2 diabetes.
Collapse
Affiliation(s)
- Lisa Juntti-Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital L1:03, SE-171 76 Stockholm, Sweden
| | | |
Collapse
|
16
|
Wilson LE, D'Aloisio AA, Sandler DP, Taylor JA. Long-term use of calcium channel blocking drugs and breast cancer risk in a prospective cohort of US and Puerto Rican women. Breast Cancer Res 2016; 18:61. [PMID: 27378129 PMCID: PMC4932734 DOI: 10.1186/s13058-016-0720-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/27/2016] [Indexed: 12/14/2022] Open
Abstract
Background In a recent case–control study, long-term use of calcium channel blocking drugs was associated with a greater-than-twofold increased breast cancer risk. If prospectively collected data confirm that calcium channel blocker use increases breast cancer risk, this would have major implications for hypertension treatment. The objective of this study was to determine whether women using calcium channel blockers for 10 years or more were at increased risk of developing breast cancer compared with women not using calcium channel blockers. Methods The Sister Study is a prospective volunteer cohort study of women from the USA and Puerto Rico designed to evaluate environmental and genetic risk factors for breast cancer. Beginning in 2003, women between the ages of 35 and 74 were recruited. They were eligible to participate if they had a sister with breast cancer but had not been diagnosed with breast cancer themselves. In total, 50,884 women enrolled in the cohort between 2003 and 2009; 50,757 women with relevant baseline data and available follow-up data are included in this study. The exposure of interest is current use of calcium channel blocking drugs and the reported duration of use at entry into the cohort. Secondary exposures of interest were the duration and frequency of use for all other subclasses of antihypertensive drugs. Our main outcome is a self-reported diagnosis of breast cancer during the study follow-up period. With patient permission, self-reported diagnoses were confirmed using medical records. Results Results showed 15,817 participants were currently using an antihypertensive drug, and 3316 women were currently using a calcium channel blocker at study baseline; 1965 women reported a breast cancer diagnosis during study follow-up. Using Cox proportional hazards modeling, we found no increased risk of breast cancer among women who had been using calcium channel blockers for 10 years or more compared with never users of calcium channel blockers (HR 0.88, 95 % CI 0.58–1.33). Conclusions We saw no evidence of increased risk of breast cancer from 10 years or more of current calcium channel blocker use. Our results do not support avoiding calcium channel blocking drugs in order to reduce breast cancer risk. Electronic supplementary material The online version of this article (doi:10.1186/s13058-016-0720-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Lauren E Wilson
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Aimee A D'Aloisio
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA.,Social & Scientific Systems, Inc., Durham, NC, 27703, USA
| | - Dale P Sandler
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Jack A Taylor
- Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA.
| |
Collapse
|
17
|
Abstract
Recent studies have shown that excitotoxicity can result in either neuronal necrosis (passive cell lysis associated with energy failure) or apoptosis (active cell death requiring energy production). The type of cell death encountered by neuronal cell cultures exposed to excessive levels of excitatory amino acids—such as glutamate, the major excitatory neurotransmitter in the central nervous system, or free radicals, such as nitric oxide (NO) and superoxide anion (O2 -), which react to form peroxynitrite (ONOO-)—depends on the intensity of the exposure and may involve two temporally distinct phases. After relatively fulminant insults, an initial phase of necrosis—associated with extreme energy depletion—may simply reflect the failure of neurons to carry out the "default" apoptotic death program used to efficiently dispose of aged or otherwise unwanted cells. Neurons that survive this initial insult recover mitochondrial membrane potential and energy charge and subsequently undergo apoptosis, which seems to be associated with a factor(s) released from mitochondria. These factors have proteolytic activity or trigger the activation of proteases (caspases), ex ecutors of the cell death program. Thus, the maintenance of balanced energy production may be a decisive factor in determining the degree, type, and progression of neuronal injury caused by excitotoxins and free radicals. Increasing evidence suggests that similar events occur in vivo after ischemia or other insults, including Alzheimer's disease, Huntington's disease, and AIDS dementia. NEUROSCIENTIST 4:345-352, 1998
Collapse
Affiliation(s)
- Stuart A. Lipton
- CNS Research Institute Brigham and Women's Hospital
and Program in Neuroscience Harvard Medical School Boston, Massachusetts (SAL)
Faculty of Biology University of Konstanz Konstanz, Germany (PN)
| | - Pierluigi Nicotera
- CNS Research Institute Brigham and Women's Hospital
and Program in Neuroscience Harvard Medical School Boston, Massachusetts (SAL)
Faculty of Biology University of Konstanz Konstanz, Germany (PN)
| |
Collapse
|
18
|
Yang G, Shi Y, Yu J, Li Y, Yu L, Welling A, Hofmann F, Striessnig J, Juntti-Berggren L, Berggren PO, Yang SN. CaV1.2 and CaV1.3 channel hyperactivation in mouse islet β cells exposed to type 1 diabetic serum. Cell Mol Life Sci 2015; 72:1197-207. [PMID: 25292336 PMCID: PMC11113900 DOI: 10.1007/s00018-014-1737-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 09/02/2014] [Accepted: 09/22/2014] [Indexed: 11/28/2022]
Abstract
The voltage-gated Ca(2+) (CaV) channel acts as a key player in β cell physiology and pathophysiology. β cell CaV channels undergo hyperactivation subsequent to exposure to type 1 diabetic (T1D) serum resulting in increased cytosolic free Ca(2+) concentration and thereby Ca(2+)-triggered β cell apoptosis. The present study was aimed at revealing the subtypes of CaV1 channels hyperactivated by T1D serum as well as the biophysical mechanisms responsible for T1D serum-induced hyperactivation of β cell CaV1 channels. Patch-clamp recordings and single-cell RT-PCR analysis were performed in pancreatic β cells from CaV1 channel knockout and corresponding control mice. We now show that functional CaV1.3 channels are expressed in a subgroup of islet β cells from CaV1.2 knockout mice (CaV1.2(-/-)). T1D serum enhanced whole-cell CaV currents in islet β cells from CaV1.3 knockout mice (CaV1.3(-/-)). T1D serum increased the open probability and number of functional unitary CaV1 channels in CaV1.2(-/-) and CaV1.3(-/-) β cells. These data demonstrate that T1D serum hyperactivates both CaV1.2 and CaV1.3 channels by increasing their conductivity and number. These findings suggest CaV1.2 and CaV1.3 channels as potential targets for anti-diabetes therapy.
Collapse
Affiliation(s)
- Guang Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
- Jilin Academy of Traditional Chinese Medicine, Changchun, 130021 China
| | - Yue Shi
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Jia Yu
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Yuxin Li
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, 130024 China
| | - Lina Yu
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Andrea Welling
- Forschergruppe, Institut für Pharmakologie und Toxikologie, Technische Universität München, 80802 München, Germany
| | - Franz Hofmann
- Forschergruppe, Institut für Pharmakologie und Toxikologie, Technische Universität München, 80802 München, Germany
| | - Jörg Striessnig
- Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Lisa Juntti-Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun, 130024 China
| |
Collapse
|
19
|
Taurine Supplementation Enhances Insulin Secretion Without Altering Islet Morphology in Non-obese Diabetic Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 803:353-70. [PMID: 25833509 DOI: 10.1007/978-3-319-15126-7_27] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
20
|
Yang SN, Shi Y, Yang G, Li Y, Yu J, Berggren PO. Ionic mechanisms in pancreatic β cell signaling. Cell Mol Life Sci 2014; 71:4149-77. [PMID: 25052376 PMCID: PMC11113777 DOI: 10.1007/s00018-014-1680-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/03/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
The function and survival of pancreatic β cells critically rely on complex electrical signaling systems composed of a series of ionic events, namely fluxes of K(+), Na(+), Ca(2+) and Cl(-) across the β cell membranes. These electrical signaling systems not only sense events occurring in the extracellular space and intracellular milieu of pancreatic islet cells, but also control different β cell activities, most notably glucose-stimulated insulin secretion. Three major ion fluxes including K(+) efflux through ATP-sensitive K(+) (KATP) channels, the voltage-gated Ca(2+) (CaV) channel-mediated Ca(2+) influx and K(+) efflux through voltage-gated K(+) (KV) channels operate in the β cell. These ion fluxes set the resting membrane potential and the shape, rate and pattern of firing of action potentials under different metabolic conditions. The KATP channel-mediated K(+) efflux determines the resting membrane potential and keeps the excitability of the β cell at low levels. Ca(2+) influx through CaV1 channels, a major type of β cell CaV channels, causes the upstroke or depolarization phase of the action potential and regulates a wide range of β cell functions including the most elementary β cell function, insulin secretion. K(+) efflux mediated by KV2.1 delayed rectifier K(+) channels, a predominant form of β cell KV channels, brings about the downstroke or repolarization phase of the action potential, which acts as a brake for insulin secretion owing to shutting down the CaV channel-mediated Ca(2+) entry. These three ion channel-mediated ion fluxes are the most important ionic events in β cell signaling. This review concisely discusses various ionic mechanisms in β cell signaling and highlights KATP channel-, CaV1 channel- and KV2.1 channel-mediated ion fluxes.
Collapse
Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76, Stockholm, Sweden,
| | | | | | | | | | | |
Collapse
|
21
|
Kondratskyi A, Kondratska K, Skryma R, Prevarskaya N. Ion channels in the regulation of apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2532-46. [PMID: 25450339 DOI: 10.1016/j.bbamem.2014.10.030] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/08/2014] [Accepted: 10/20/2014] [Indexed: 02/07/2023]
Abstract
Apoptosis, a type of genetically controlled cell death, is a fundamental cellular mechanism utilized by multicellular organisms for disposal of cells that are no longer needed or potentially detrimental. Given the crucial role of apoptosis in physiology, deregulation of apoptotic machinery is associated with various diseases as well as abnormalities in development. Acquired resistance to apoptosis represents the common feature of most and perhaps all types of cancer. Therefore, repairing and reactivating apoptosis represents a promising strategy to fight cancer. Accumulated evidence identifies ion channels as essential regulators of apoptosis. However, the contribution of specific ion channels to apoptosis varies greatly depending on cell type, ion channel type and intracellular localization, pathology as well as intracellular signaling pathways involved. Here we discuss the involvement of major types of ion channels in apoptosis regulation. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
Collapse
Affiliation(s)
- Artem Kondratskyi
- Inserm, U-1003, Equipe labellisée par la Ligue Nationale Contre le Cancer, Laboratory of Excellence, Ion Channels Science and Therapeutics, Université Lille 1, Villeneuve d'Ascq, France
| | - Kateryna Kondratska
- Inserm, U-1003, Equipe labellisée par la Ligue Nationale Contre le Cancer, Laboratory of Excellence, Ion Channels Science and Therapeutics, Université Lille 1, Villeneuve d'Ascq, France
| | - Roman Skryma
- Inserm, U-1003, Equipe labellisée par la Ligue Nationale Contre le Cancer, Laboratory of Excellence, Ion Channels Science and Therapeutics, Université Lille 1, Villeneuve d'Ascq, France
| | - Natalia Prevarskaya
- Inserm, U-1003, Equipe labellisée par la Ligue Nationale Contre le Cancer, Laboratory of Excellence, Ion Channels Science and Therapeutics, Université Lille 1, Villeneuve d'Ascq, France.
| |
Collapse
|
22
|
Yamamoto T, Obika S, Nakatani M, Yasuhara H, Wada F, Shibata E, Shibata MA, Harada-Shiba M. Locked nucleic acid antisense inhibitor targeting apolipoprotein C-III efficiently and preferentially removes triglyceride from large very low-density lipoprotein particles in murine plasma. Eur J Pharmacol 2013; 723:353-9. [PMID: 24269597 DOI: 10.1016/j.ejphar.2013.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 10/25/2013] [Accepted: 11/02/2013] [Indexed: 10/26/2022]
Abstract
A 20-mer phosphorothioate antisense oligodeoxyribonucleotide having locked nucleic acids (LNA-AON) was used to reduce elevated serum triglyceride levels in mice. We repeatedly administered LNA-AON, which targets murine apolipoprotein C-III mRNA, to high-fat-fed C57Bl/6J male mice for 2 weeks. The LNA-AON showed efficient dose-dependent reductions in hepatic apolipoprotein C-III mRNA and decreased serum apolipoprotein C-III protein concentrations, along with efficient dose-dependent reductions in serum triglyceride concentrations and attenuation of fat accumulation in the liver. Through precise lipoprotein profiling analysis of sera, we found that serum reductions in triglyceride and cholesterol levels were largely a result of decreased serum very low-density lipoprotein (VLDL)-triglycerides and -cholesterol. It is noteworthy that larger VLDL particles were more susceptible to removal from blood than smaller particles, resulting in a shift in particle size distribution to smaller diameters. Histopathologically, fatty changes were markedly reduced in antisense-treated mice, while moderate granular degeneration was frequently seen the highest dose of LNA-AON. The observed granular degeneration of hepatocytes may be associated with moderate elevation in the levels of serum transaminases. In conclusion, we developed an LNA-based selective inhibitor of apolipoprotein C-III. Although it remains necessary to eliminate its potential hepatotoxicity, the present LNA-AON will be helpful for further elucidating the molecular biology of apolipoprotein C-III.
Collapse
Affiliation(s)
- Tsuyoshi Yamamoto
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
| | - Satoshi Obika
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Moeka Nakatani
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
| | - Hidenori Yasuhara
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
| | - Fumito Wada
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
| | - Eiko Shibata
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan; Graduate School of Health Sciences, Osaka Health Science University, Osaka, Japan.
| | - Masa-Aki Shibata
- Graduate School of Health Sciences, Osaka Health Science University, Osaka, Japan.
| | - Mariko Harada-Shiba
- Department of Molecular Innovation in Lipidology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
| |
Collapse
|
23
|
Shi Y, Yang G, Yu J, Yu L, Westenbroek R, Catterall WA, Juntti-Berggren L, Berggren PO, Yang SN. Apolipoprotein CIII hyperactivates β cell CaV1 channels through SR-BI/β1 integrin-dependent coactivation of PKA and Src. Cell Mol Life Sci 2013; 71:1289-303. [PMID: 23949443 DOI: 10.1007/s00018-013-1442-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 07/06/2013] [Accepted: 07/29/2013] [Indexed: 11/30/2022]
Abstract
Apolipoprotein CIII (ApoCIII) not only serves as an inhibitor of triglyceride hydrolysis but also participates in diabetes-related pathological events such as hyperactivation of voltage-gated Ca(2+) (CaV) channels in the pancreatic β cell. However, nothing is known about the molecular mechanisms whereby ApoCIII hyperactivates β cell CaV channels. We now demonstrate that ApoCIII increased CaV1 channel open probability and density. ApoCIII enhanced whole-cell Ca(2+) currents and the CaV1 channel blocker nimodipine completely abrogated this enhancement. The effect of ApoCIII was not influenced by individual inhibition of PKA, PKC, or Src. However, combined inhibition of PKA, PKC, and Src counteracted the effect of ApoCIII, similar results obtained by coinhibition of PKA and Src. Moreover, knockdown of β1 integrin or scavenger receptor class B type I (SR-BI) prevented ApoCIII from hyperactivating β cell CaV channels. These data reveal that ApoCIII hyperactivates β cell CaV1 channels through SR-BI/β1 integrin-dependent coactivation of PKA and Src.
Collapse
Affiliation(s)
- Yue Shi
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76, Stockholm, Sweden
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Men X, Peng L, Wang H, Zhang W, Xu S, Fang Q, Liu H, Yang W, Lou J. Involvement of the Ca2+-responsive transactivator in high glucose-induced β-cell apoptosis. J Endocrinol 2013; 216:231-43. [PMID: 23160962 DOI: 10.1530/joe-12-0286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The calcium-regulated transcription coactivator, Ca(2)(+)-responsive transactivator (CREST) was expressed in pancreatic β-cells. Moreover, CREST expression became significantly increased in pancreatic islets isolated from hyperglycemic Goto-Kakizaki rats compared with normoglycemic Wistar controls. In addition, culture of β-cells in the presence of high glucose concentrations also increased CREST expression in vitro. To further investigate the role of this transactivator in the regulation of β-cell function, we established a stable β-cell line with inducible CREST expression. Hence, CREST overexpression mimicked the glucotoxic effects on insulin secretion and cell growth in β-cells. Moreover, high glucose-induced apoptosis was aggravated by upregulation of the transactivator but inhibited when CREST expression was partially silenced by siRNA technology. Further investigation found that upregulation of Bax and downregulation of Bcl2 was indeed induced by its expression, especially under high glucose conditions. In addition, as two causing factors leading to β-cell apoptosis under diabetic conditions, endoplasmic reticulum stress and high free fatty acid, mimicked the high glucose effects on CREST upregulation and generation of apoptosis in β-cells, and these effects were specifically offset by the siRNA knockdown of CREST. These results indicated that CREST is implicated in β-cell apoptosis induced by culture in high glucose and hence that CREST may become a potential pharmacological target for the prevention and treatment of type 2 diabetes mellitus.
Collapse
Affiliation(s)
- Xiuli Men
- Department of Pathophysiology, Hebei United University, Tangshan 063000, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
Apoptotic cell death is characterized by cell shrinkage, chromatin condensation and fragmentation, formation of apoptotic bodies and phagocytosis (Kerr et al., 1972). At the molecular level, activation of a family of cysteine proteases, caspases, related to interleukin-1beta-converting enzyme is believed to be a crucial event in apoptosis. This is associated with the proteolysis of nuclear and cytoskeletal proteins, cell shrinkage, glutathione efflux, exposure of phosphatidylserine on the cell surface, membrane blebbing, etc. In CD95- or TNF-mediated apoptosis, the proteolytic cascade is believed to be triggered directly by caspase binding to the activated plasma membrane receptor complex. In other forms of apoptosis, the mechanisms of activation of the proteolytic cascade are less well established but may involve imported proteases, such as granzyme B, or factors released from the mitochondria and, possibly, other organelles. Recently, the possibility that cytochrome c released from the mitochondria may serve to activate dormant caspases in the cytosol, and thereby to propagate the apoptotic process, has attracted considerable attention. A perturbation of intracellular Ca(2+) homeostasis has been found to trigger apoptosis in many experimental systems, and the apoptotic process has been related to either a sustained increase in cytosolic free Ca(2+) level or a depletion of intracellular Ca(2+) stores. Although many of the biochemical events involved in the apoptotic process are Ca(2+) dependent, the exact mechanism by which Ca(2+) triggers apoptosis remains unknown. The bcl-2 gene family, which includes both inhibitors and inducers of apoptosis, appears to regulate intracellular Ca(2+) compartmentalization. The induction of apoptosis by Ca(2+)-mobilizing agents results in caspase activation, which is similar to what is seen with other inducers of apoptosis. In addition, Ca(2+)-dependent proteases, such as calpain and a Ca(2+)-dependent nuclear scaffold-associated serine protease, are also activated by Ca(2+) signalling in some cell types where they appear to be involved in alpha-fodrin and lamin beta cleavage, respectively. Thus, a spectrum of proteases are activated during apoptosis depending on both cell type and inducer. This proteolytic cascade can involve both caspases and Ca(2+)-dependent proteases, which seem to interact during the apoptotic process.
Collapse
Affiliation(s)
- M I Pörn-Ares
- Institute of Environmental Medicine, Division of Toxicology, Stockholm, Sweden
| | | | | |
Collapse
|
26
|
Ramadan JW, Steiner SR, O'Neill CM, Nunemaker CS. The central role of calcium in the effects of cytokines on beta-cell function: implications for type 1 and type 2 diabetes. Cell Calcium 2011; 50:481-90. [PMID: 21944825 DOI: 10.1016/j.ceca.2011.08.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/20/2011] [Accepted: 08/16/2011] [Indexed: 12/29/2022]
Abstract
The appropriate regulation of intracellular calcium is a requirement for proper cell function and survival. This review focuses on the effects of proinflammatory cytokines on calcium regulation in the insulin-producing pancreatic beta-cell and how normal stimulus-secretion coupling, organelle function, and overall beta-cell viability are impacted. Proinflammatory cytokines are increasingly thought to contribute to beta-cell dysfunction not only in type 1 diabetes (T1D), but also in the progression of type 2 diabetes (T2D). Cytokine-induced disruptions in calcium handling result in reduced insulin release in response to glucose stimulation. Cytokines can alter intracellular calcium levels by depleting calcium from the endoplasmic reticulum (ER) and by increasing calcium influx from the extracellular space. Depleting ER calcium leads to protein misfolding and activation of the ER stress response. Disrupting intracellular calcium may also affect organelles, including the mitochondria and the nucleus. As a chronic condition, cytokine-induced calcium disruptions may lead to beta-cell death in T1D and T2D, although possible protective effects are also discussed. Calcium is thus central to both normal and pathological cell processes. Because the tight regulation of intracellular calcium is crucial to homeostasis, measuring the dynamics of calcium may serve as a good indicator of overall beta-cell function.
Collapse
Affiliation(s)
- James W Ramadan
- Department of Medicine, University of Virginia, Charlottesville, United States
| | | | | | | |
Collapse
|
27
|
Lowering apolipoprotein CIII delays onset of type 1 diabetes. Proc Natl Acad Sci U S A 2011; 108:10685-9. [PMID: 21670290 DOI: 10.1073/pnas.1019553108] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Serum levels of apolipoprotein CIII (apoCIII) are increased in type 1 diabetic patients, and when β cells are exposed to these diabetic sera, apoptosis occurs, an effect abolished by an antibody against apoCIII. We have investigated the BB rat, an animal model that develops a human-like type 1 diabetes, and found that apoCIII was also increased in sera from prediabetic rats. This increase in apoCIII promoted β-cell death. The endogenous levels of apoCIII were reduced by treating prediabetic animals with an antisense against this apolipoprotein, resulting in a significantly delayed onset of diabetes. ApoCIII thus serves as a diabetogenic factor, and intervention with this apolipoprotein in the prediabetic state can arrest disease progression. These findings suggest apoCIII as a target for the treatment of type 1 diabetes.
Collapse
|
28
|
Parkash J, Asotra K. L-histidine sensing by calcium sensing receptor inhibits voltage-dependent calcium channel activity and insulin secretion in β-cells. Life Sci 2011; 88:440-6. [PMID: 21219913 PMCID: PMC3044179 DOI: 10.1016/j.lfs.2010.12.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 11/22/2010] [Accepted: 12/14/2010] [Indexed: 12/29/2022]
Abstract
AIMS Our goal was to test the hypothesis that the histidine-induced activation of calcium sensing receptor (CaR) can regulate calcium channel activity of L-type voltage dependent calcium channel (VDCC) due to increased spatial interaction between CaR and VDCC in β-cells and thus modulate glucose-induced insulin secretion. MAIN METHODS Rat insulinoma (RINr1046-38) insulin-producing β-cells were cultured in RPMI-1640 medium on 25 mm diameter glass coverslips in six-well culture plates in a 5% CO(2) incubator at 37°C. The intracellular calcium concentration, [Ca(2+)](i), was determined by ratio fluorescence microscopy using Fura-2AM. The spatial interactions between CaR and L-type VDCC in β-cells were measured by immunofluorescence confocal microscopy using a Nikon C1 laser scanning confocal microscope. The insulin release was determined by enzyme-linked immunosorbent assay (ELISA). KEY FINDINGS The addition of increasing concentrations of L-histidine along with 10 mM glucose resulted in 57% decrease in [Ca(2+)](i). The confocal fluorescence imaging data showed 5.59 to 8.62-fold increase in colocalization correlation coefficient between CaR and VDCC in β-cells exposed to L-histidine thereby indicating increased membrane delimited spatial interactions between these two membrane proteins. The insulin ELISA data showed 54% decrease in the 1st phase of glucose-induced insulin secretion in β-cells exposed to increasing concentrations of L-histidine. SIGNIFICANCE L-histidine-induced increased spatial interaction of CaR with VDCC can inhibit calcium channel activity of VDCC and consequently regulate glucose-induced insulin secretion by β-cells. The L-type VDCC could therefore be a potential therapeutic target in diabetes.
Collapse
Affiliation(s)
- Jai Parkash
- Robert Stempel College of Public Health and Social Work, Department of Environmental and Occupational Health, Florida International University, 11200 SW 8 Street, HLS-594, Miami, FL 33199, USA
| | - Kamlesh Asotra
- Cardiovascular Disease and General Biomedical Sciences, Tobacco-Related Disease Research Program, University of California Office of President, 300 Lakeside Drive, Oakland, CA 94612, USA, Tel: (510) 287-3366, FAX: (510) 835-4740,
| |
Collapse
|
29
|
Parkash J. Glucose-mediated spatial interactions of voltage dependent calcium channels and calcium sensing receptor in insulin producing β-cells. Life Sci 2010; 88:257-64. [PMID: 21146545 DOI: 10.1016/j.lfs.2010.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 11/12/2010] [Accepted: 11/15/2010] [Indexed: 01/03/2023]
Abstract
AIMS The voltage dependent calcium channel (VDCC) e.g., L-type VDCC plays critical roles in the spatio-temporal regulation of intracellular calcium concentration ([Ca(2+)](i)) and insulin secretion by β-cell. This study describes the involvement of 2.5 to 15mM glucose-induced spatial interactions between a calcium sensing receptor (CaR) and L-type VDCC in controlling Ca(2+) channel activity and insulin secretion in β-cells in association with the nuclear translocation of a transcription factor nuclear factor kappa B (NF-κB). MAIN METHODS The insulin producing β-cells were exposed to 2.5, 5, 7.5, 10, and 15 mM glucose for 24 h at 37 °C. The confocal fluorescence imaging data was obtained by using antibodies against CaR and L-type VDCC. The nuclear translocation of NF-κB was measured by confocal fluorescence imaging using antibody against NF-κB. The insulin release was determined by enzyme-linked immunosorbent assay (ELISA). KEY FINDINGS The confocal imaging data showed 6 to 12-fold enhancement in the colocalization correlation coefficient between CaR and VDCC in β-cells exposed to glucose thereby indicating increased membrane delimited spatial interactions between these two membrane proteins. The confocal fluorescence imaging data showed that addition of glucose to β-cells led to 1.8 to 2.7-fold increase in the nuclear translocation of NF-κB. The insulin ELISA data showed a significant increase in the 1st phase of glucose-induced insulin secretion in β-cells exposed to increasing concentrations of glucose. SIGNIFICANCE The results described in the present study further strengthen that VDCC and CaR can interact spatially to allow control over calcium channel activity and therefore glucose-induced insulin secretion by β-cells.
Collapse
Affiliation(s)
- Jai Parkash
- Robert Stempel College of Public Health and Social Work, Department of Environmental and Occupational Health, Florida International University, Miami, FL 33199, USA.
| |
Collapse
|
30
|
Dula SB, Jecmenica M, Wu R, Jahanshahi P, Verrilli GM, Carter JD, Brayman KL, Nunemaker CS. Evidence that low-grade systemic inflammation can induce islet dysfunction as measured by impaired calcium handling. Cell Calcium 2010; 48:133-42. [PMID: 20800281 PMCID: PMC2948622 DOI: 10.1016/j.ceca.2010.07.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 07/08/2010] [Accepted: 07/24/2010] [Indexed: 02/05/2023]
Abstract
In obesity and the early stages of type 2 diabetes (T2D), proinflammatory cytokines are mildly elevated in the systemic circulation. This low-grade systemic inflammation exposes pancreatic islets to these circulating cytokines at much lower levels than seen within the islet during insulitis. These low-dose effects have not been well described. We examined mouse islets treated overnight with a low-dose cytokine combination commonly associated with inflammation (TNF-alpha, IL-1 beta, and IFN-gamma). We then examined islet function primarily using intracellular calcium ([Ca(2+)](i)), a key component of insulin secretion and cytokine signaling. Cytokine-treated islets demonstrated several features that suggested dysfunction including excess [Ca(2+)](i) in low physiological glucose (3mM), reduced responses to glucose stimulation, and disrupted [Ca(2+)](i) oscillations. Interestingly, islets taken from young db/db mice showed similar disruptions in [Ca(2+)](i) dynamics as cytokine-treated islets. Additional studies of control islets showed that the cytokine-induced elevation in basal [Ca(2+)](i) was due to both greater calcium influx through L-type-calcium-channels and reduced endoplasmic reticulum (ER) calcium storage. Many of these cytokine-induced disruptions could be reproduced by SERCA blockade. Our data suggest that chronic low-grade inflammation produces circulating cytokine levels that are sufficient to induce beta-cell dysfunction and may play a contributing role in beta-cell failure in early T2D.
Collapse
Affiliation(s)
- Stacey B. Dula
- Department of Medicine, University of Virginia, Charlottesville, VA
| | - Mladen Jecmenica
- Department of Surgery, University of Virginia, Charlottesville, VA
| | - Runpei Wu
- Department of Medicine, University of Virginia, Charlottesville, VA
| | - Pooya Jahanshahi
- Department of Medicine, University of Virginia, Charlottesville, VA
| | | | | | | | | |
Collapse
|
31
|
Enhancement of β-Cell Regeneration by Islet Transplantation After Partial Pancreatectomy in Mice. Transplantation 2009; 88:354-9. [DOI: 10.1097/tp.0b013e3181b07a02] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
32
|
Gomez-Pinilla PJ, Camello PJ, Pozo MJ. Pancreatic calcium signaling: role in health and disease. Pancreatology 2009; 9:329-33. [PMID: 19451741 DOI: 10.1159/000213412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In order to control cell functions, extracellular agents, such as hormones or neurotransmitters among others, generate a diversity of calcium (Ca(2+)) signals in target cells. Here, we review the components involved in Ca(2+) handling and effectors, both members of the known calcium signaling pathways. In the pancreas, Ca(2+) signal appears as local increases, global elevations or Ca(2+) oscillations. Ca(2+) plays a key role in the pancreatic cells, regulating secretion in exocrine cells, a widely used model for studying the coupling between Ca(2+) signaling and secretion, and the release of insulin, glucagon and somatostatin in the exocrine pancreas. Interestingly, Ca(2+) deregulations have been related to pancreatitis and aging of the pancreas, and treatment with melatonin has shown beneficial effects suggesting that melatonin could be an adequate therapeutic approach.
Collapse
Affiliation(s)
- Pedro J Gomez-Pinilla
- Department of Physiology, Nursing School, University of Extremadura, Cáceres, Spain.
| | | | | |
Collapse
|
33
|
Parkash J. Tumor Necrosis Factor Alpha Inducing Spatial Interactions between Calcium-Sensing Receptor and L-Type Voltage-Dependent Calcium Channel. Ann N Y Acad Sci 2008; 1150:320-2. [DOI: 10.1196/annals.1447.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
34
|
A novel autoantibody in patients with primary hypertension: antibody against L-type Ca2+ channel. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200808020-00003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
35
|
Dekki N, Nilsson R, Norgren S, Rössner SM, Appelskog I, Marcus C, Simell O, Pugliese A, Alejandro R, Ricordi C, Berggren PO, Juntti-Berggren L. Type 1 diabetic serum interferes with pancreatic beta-cell Ca2+-handling. Biosci Rep 2008; 27:321-6. [PMID: 17597394 DOI: 10.1007/s10540-007-9055-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The aim of this study was to clarify the frequency of patients with type 1 diabetes that have serum that increases pancreatic beta-cell cytoplasmic free Ca(2+) concentration, [Ca(2+)](i), and if such an effect is also present in serum from first-degree relatives. We also studied a possible link between the serum effect and ethnic background as well as presence of autoantibodies. Sera obtained from three different countries were investigated as follows: 82 Swedish Caucasians with newly diagnosed type 1 diabetes, 56 Americans with different duration of type 1 diabetes, 117 American first-degree relatives of type 1 diabetic patients with a mixed ethnic background and 31 Caucasian Finnish children with newly diagnosed type 1 diabetes. Changes in [Ca(2+)](i) , upon depolarization, were measured in beta-cells incubated overnight with sera from type 1 diabetic patients, first-degree relatives or healthy controls. Our data show that there is a group constituting approximately 30% of type 1 diabetic patients of different gender, age, ethnic background and duration of the disease, as well as first-degree relatives of type 1 diabetic patients, that have sera that interfere with pancreatic beta-cell Ca(2+)-handling. This effect on beta-cell [Ca(2+)](i) could not be correlated to the presence of autoantibodies. In a defined subgroup of patients with type 1 diabetes and first-degree relatives a defect Ca(2+)-handling may aggravate development of beta-cell destruction.
Collapse
Affiliation(s)
- N Dekki
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University Hospital, L1, Stockholm, 171 76, Sweden
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
Although inhibition of voltage-gated calcium channels by RGK GTPases (RGKs) represents an important mode of regulation to control Ca2+ influx in excitable cells, their exact mechanism of inhibition remains controversial. This has prevented an understanding of how RGK regulation can be significant in a physiological context. Here we show that RGKs—Gem, Rem, and Rem2—decreased CaV1.2 Ca2+ current amplitude in a dose-dependent manner. Moreover, Rem2, but not Rem or Gem, produced dose-dependent alterations on gating kinetics, uncovering a new mode by which certain RGKs can precisely modulate Ca2+ currents and affect Ca2+ influx during action potentials. To explore how RGKs influence gating kinetics, we separated the roles mediated by the Ca2+ channel accessory β subunit's interaction with its high affinity binding site in the pore-forming α1C subunit (AID) from its other putative contact sites by utilizing an α1C•β3 concatemer in which the AID was mutated to prevent β subunit interaction. This mutant concatemer generated currents with all the hallmarks of β subunit modulation, demonstrating that AID-β–independent interactions are sufficient for β subunit modulation. Using this construct we found that although inhibition of current amplitude was still partially sensitive to RGKs, Rem2 no longer altered gating kinetics, implicating different determinants for this specific mode of Rem2-mediated regulation. Together, these results offer new insights into the molecular mechanism of RGK-mediated Ca2+ channel current modulation.
Collapse
Affiliation(s)
- Lillian Seu
- Department of Pharmacology, Division of Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
| | | |
Collapse
|
37
|
Yang SN, Berggren PO. The role of voltage-gated calcium channels in pancreatic beta-cell physiology and pathophysiology. Endocr Rev 2006; 27:621-76. [PMID: 16868246 DOI: 10.1210/er.2005-0888] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Voltage-gated calcium (CaV) channels are ubiquitously expressed in various cell types throughout the body. In principle, the molecular identity, biophysical profile, and pharmacological property of CaV channels are independent of the cell type where they reside, whereas these channels execute unique functions in different cell types, such as muscle contraction, neurotransmitter release, and hormone secretion. At least six CaValpha1 subunits, including CaV1.2, CaV1.3, CaV2.1, CaV2.2, CaV2.3, and CaV3.1, have been identified in pancreatic beta-cells. These pore-forming subunits complex with certain auxiliary subunits to conduct L-, P/Q-, N-, R-, and T-type CaV currents, respectively. beta-Cell CaV channels take center stage in insulin secretion and play an important role in beta-cell physiology and pathophysiology. CaV3 channels become expressed in diabetes-prone mouse beta-cells. Point mutation in the human CaV1.2 gene results in excessive insulin secretion. Trinucleotide expansion in the human CaV1.3 and CaV2.1 gene is revealed in a subgroup of patients with type 2 diabetes. beta-Cell CaV channels are regulated by a wide range of mechanisms, either shared by other cell types or specific to beta-cells, to always guarantee a satisfactory concentration of Ca2+. Inappropriate regulation of beta-cell CaV channels causes beta-cell dysfunction and even death manifested in both type 1 and type 2 diabetes. This review summarizes current knowledge of CaV channels in beta-cell physiology and pathophysiology.
Collapse
Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology L1:03, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden.
| | | |
Collapse
|
38
|
Kang YH, Lee KA, Ryu CJ, Lee HG, Lim JS, Park SN, Paik SG, Yoon DY. Mitomycin C induces apoptosis via Fas/FasL dependent pathway and suppression of IL-18 in cervical carcinoma cells. Cancer Lett 2006; 237:33-44. [PMID: 16019139 DOI: 10.1016/j.canlet.2005.05.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 03/02/2005] [Accepted: 05/20/2005] [Indexed: 10/25/2022]
Abstract
Mitomycin C (MMC) is used fairly widely as an anticancer drug, as it possesses mechanisms of action which are preferable to other chemotherapeutic compounds, including cisplatin, docetaxel, and lovastatin. In the previous study, we established the RSV-luc promoter analysis system, which is used to screen drugs against cervical carcinomas caused by HPV infection. We then demonstrated the repression of HPV E6-activated RSV promoter activity by anticancer agents such as carboplatin (CA), cisplatin (CIS), and MMC. In these studies, we focused on the investigation of apoptotic mechanisms in MMC-treated cervical carcinoma cell lines, most notably SiHa/pRSV-luc (KCTC 0427BP) and SiHa. DNA fragmentation assays and TUNEL staining revealed that MMC and CIS, but not CA, resulted in apoptosis. MMC treatment induced a reduction in the expressions of the E6 oncogene and IL-18, in a p53-independent manner. MMC also increased FasL expression and induced the processing of caspases-8 and -3. Our results indicated that MMC induced apoptosis in SiHa/pRSV-luc and SiHa cells via caspase-8 and -3 processing, in a Fas/FasL-dependent manner. MMC also suppressed the expression of IL-18 in the same cells. MMC also down-regulated IkappaB expression, and up-regulated p65 expression. These results suggest that MMC induces apoptosis, not only through caspase-8 and -3 dependent Fas/FasL pathway, but also via the regulation of NF-kappaB activity and IL-18 expression.
Collapse
Affiliation(s)
- Yun Hee Kang
- Division of Cellomics, Laboratory of Cell Biology, Korea Research Institute of Bioscience and Biotechnology, P.O. Box 115, Daejeon 305-600, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Berggren PO, Leibiger IB. Novel aspects on signal-transduction in the pancreatic beta-cell. Nutr Metab Cardiovasc Dis 2006; 16 Suppl 1:S7-S10. [PMID: 16530130 DOI: 10.1016/j.numecd.2005.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 11/08/2005] [Accepted: 11/08/2005] [Indexed: 11/27/2022]
Abstract
The glucose-stimulus/insulin-secretion-coupling by the pancreatic beta-cell, which guarantees the maintenance of glucose homeostasis in man, is regulated by a sophisticated interplay between glucose and a plethora of additional factors. Besides other nutrients, incretins, nerval innervation, systemic growth factors as well as autocrine and paracrine regulatory loops within the islet of Langerhans modulate the function of the insulin-producing beta-cell. Although the modulatory role of these factors is well appreciated, the underlying molecular mechanisms involved remain poorly understood. However, in most cases beta-cell membrane receptors coupled primarily to either G-proteins or tyrosine kinases, which subsequently activate respective second messenger cascades, are involved. In the present mini-review we will discuss the role of signaling through some of these receptor-operated effector systems in the light of pancreatic beta-cell signal-transduction.
Collapse
Affiliation(s)
- Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska University Hospital Solna L3, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
| | | |
Collapse
|
40
|
Refai E, Dekki N, Yang SN, Imreh G, Cabrera O, Yu L, Yang G, Norgren S, Rössner SM, Inverardi L, Ricordi C, Olivecrona G, Andersson M, Jörnvall H, Berggren PO, Juntti-Berggren L. Transthyretin constitutes a functional component in pancreatic beta-cell stimulus-secretion coupling. Proc Natl Acad Sci U S A 2005; 102:17020-5. [PMID: 16286652 PMCID: PMC1287967 DOI: 10.1073/pnas.0503219102] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transthyretin (TTR) is a transport protein for thyroxine and, in association with retinol-binding protein, for retinol, mainly existing as a tetramer in vivo. We now demonstrate that TTR tetramer has a positive role in pancreatic beta-cell stimulus-secretion coupling. TTR promoted glucose-induced increases in cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) and insulin release. This resulted from a direct effect on glucose-induced electrical activity and voltage-gated Ca(2+) channels. TTR also protected against beta-cell apoptosis. The concentration of TTR tetramer was decreased, whereas that of a monomeric form was increased in sera from patients with type 1 diabetes. The monomer was without effect on glucose-induced insulin release and apoptosis. Thus, TTR tetramer constitutes a component in normal beta-cell function. Conversion of TTR tetramer to monomer may be involved in the development of beta-cell failure/destruction in type 1 diabetes.
Collapse
Affiliation(s)
- Essam Refai
- Department of Medical Biochemistry and Biophysics, The Rolf Luft Center for Diabetes Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Tang R, Liu H, Wang T, Huang K. Mechanisms of selenium inhibition of cell apoptosis induced by oxysterols in rat vascular smooth muscle cells. Arch Biochem Biophys 2005; 441:16-24. [PMID: 16039982 DOI: 10.1016/j.abb.2005.06.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 05/18/2005] [Accepted: 06/13/2005] [Indexed: 10/25/2022]
Abstract
Our previous study reported that oxysterol cholestane-3beta,5 alpha, 6 beta-triol (Triol) induced vascular smooth muscle cells (VSMCs) apoptosis, which was inhibited by selenium pretreatment. To further investigate the mechanisms of the inhibition, the glutathione peroxidase (GPx) activity, the total antioxidant capacity (T-AOC), the total superoxide dismutase (SOD) activity, and the level of lipid peroxidation (the content of malondialdehyde, MDA) of VSMCs were measured, and fluidity of cell membrane, reactive oxygen species (ROS) level, the reduction of mitochondrial membrane potential (Delta psi(m)), and the intracellular Ca(2+) in single cell were detected using several fluorescence indicators. Meanwhile, the mRNA levels of c-myc, bcl-2, GPx, and thioredoxin reductase (TR) were measured by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. The results showed that the decrease of GPx activity, T-AOC, SOD activity, the fluidity of cell membrane, the Delta psi(m), and the mRNA expression of c-myc, bcl-2, GPx, and TR of VSMCs and the increase of MDA, ROS generation, and intracellular Ca(2+), significantly induced by Triol (10 microM, 24h) were inhibited to a different extent, respectively, when cells were pretreated with sodium selenite (50 nM, 12 or 24h) before exposure to Triol. These effects were time dependent and enhanced with prolongation of the time of pretreatment. In conclusion, the results in the present work showed that the mechanism of selenium inhibition of cell apoptosis induced by oxysterols in rat VSMCs was related with the antioxidation of selenoproteins.
Collapse
MESH Headings
- Animals
- Apoptosis/drug effects
- Cells, Cultured
- Cholestanols/pharmacology
- Drug Combinations
- Male
- Membrane Fluidity/drug effects
- Mitochondria/drug effects
- Mitochondria/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Selenium/pharmacology
- Sterols/pharmacology
Collapse
Affiliation(s)
- Rong Tang
- Department of Chemistry, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | | | | | | |
Collapse
|
42
|
Kaya Dağistanli F, Süsleyici Duman B, Oztürk M. Protective effects of a calcium channel blocker on apoptosis in thymus of neonatal STZ-diabetic rats. Acta Histochem 2005; 107:207-14. [PMID: 15964614 DOI: 10.1016/j.acthis.2005.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Streptozotocin (STZ) is known to induce insulin-dependent diabetes in experimental animals. In STZ-induced diabetes, atrophy of the thymus is caused by elevated intracellular calcium levels leading to apoptosis. Hyperglycemia is known to result in a decrease in numbers of T cells in the thymus and circulation. Intracellular calcium levels increase in diabetic animals after induction by STZ. Hyperglycemia inhibits Ca2+-ATPase and increases intracellular calcium levels. We have investigated apoptosis in thymus tissue of neonatal STZ (n-STZ)-diabetic rats and the effects of isradipine as a calcium channel blocker (CCB) on apoptosis. Five groups of newborn Wistar rats were used. On the second day after birth, 100 mg/kg STZ was given i.p. to the first two groups. The first group was n-STZ diabetic. To the second group, starting from the 12th week, 5 mg/kg/day isradipine (i.p) was given for 6 weeks. To the third group, the same dose of isradipine was given on the second day, followed by STZ treatment. The fourth group was non-diabetic and treated with 5 mg/kg/day isradipine for six weeks. The fifth group consisted of non-diabetic rats. To the sixth group, dexamethasone (5 mg/kg i.p.) was given to adult rats. For detection of apoptotic cells in paraffin-embedded thymus sections, the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) assay was used. The DNA ladder method was performed for analysis of DNA fragmentation. In the isradipine-treated non-diabetic group, typical apoptotic banding patterns were found, whereas thick bands between 123 and 246 bp length were found in the n-STZ- and n-STZ+isradipine-treated groups. More apoptotic cells were observed in the thymus of isradipine-treated, n-STZ-treated and n-STZ+isradipine-treated groups when compared with the non-diabetic control and isradipine+n-STZ-treated groups. In conclusion, we observed that long-term STZ diabetes results in apoptosis in the thymus. We also found that isradipine administered before STZ has protective effects against apoptosis, whereas isradipine alone induces apoptosis.
Collapse
Affiliation(s)
- Fatma Kaya Dağistanli
- Department of Medical Biology, Cerrahpasa Faculty of Medicine, Istanbul University, Cerrahpasa 34303, Istanbul, Turkey
| | | | | |
Collapse
|
43
|
Størling J, Zaitsev SV, Kapelioukh IL, Karlsen AE, Billestrup N, Berggren PO, Mandrup-Poulsen T. Calcium has a permissive role in interleukin-1beta-induced c-jun N-terminal kinase activation in insulin-secreting cells. Endocrinology 2005; 146:3026-36. [PMID: 15831571 DOI: 10.1210/en.2005-0036] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The c-jun N-terminal kinase (JNK) signaling pathway mediates IL-1beta-induced apoptosis in insulin-secreting cells, a mechanism relevant to the destruction of pancreatic beta-cells in type 1 and 2 diabetes. However, the mechanisms that contribute to IL-1beta activation of JNK in beta-cells are largely unknown. In this study, we investigated whether Ca(2+) plays a role for IL-1beta-induced JNK activation. In insulin-secreting rat INS-1 cells cultured in the presence of 11 mm glucose, combined pharmacological blockade of L- and T-type Ca(2+) channels suppressed IL-1beta-induced in vitro phosphorylation of the JNK substrate c-jun and reduced IL-1beta-stimulated activation of JNK1/2 as assessed by immunoblotting. Inhibition of IL-1beta-induced in vitro kinase activity toward c-jun after collective L- and T-type Ca(2+) channel blockade was confirmed in primary rat and ob/ob mouse islets and in mouse betaTC3 cells. Ca(2+) influx, specifically via L-type but not T-type channels, contributed to IL-1beta activation of JNK. Activation of p38 and ERK in response to IL-1beta was also dependent on L-type Ca(2+) influx. Membrane depolarization by KCl, exposure to high glucose, treatment with Ca(2+) ionophore A23187, or exposure to thapsigargin, an inhibitor of sarco(endo)plasmic reticulum Ca(2+) ATPase, all caused an amplification of IL-1beta-induced JNK activation in INS-1 cells. Finally, a chelator of intracellular free Ca(2+) [bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid-acetoxymethyl], an inhibitor of calmodulin (W7), and inhibitors of Ca(2+)/calmodulin-dependent kinase (KN62 and KN93) partially reduced IL-1beta-stimulated c-jun phosphorylation in INS-1 or betaTC3 cells. Our data suggest that Ca(2+) plays a permissive role in IL-1beta activation of the JNK signaling pathway in insulin-secreting cells.
Collapse
Affiliation(s)
- Joachim Størling
- Laboratory for Beta-Cell Biology, Steno Diabetes Center, Niels Steensensvej 8, NSPP, DK-2820 Gentofte, Denmark.
| | | | | | | | | | | | | |
Collapse
|
44
|
Benoff S, Goodwin LO, Millan C, Hurley IR, Pergolizzi RG, Marmar JL. Deletions in L-type calcium channel α1 subunit testicular transcripts correlate with testicular cadmium and apoptosis in infertile men with varicoceles. Fertil Steril 2005; 83:622-34. [PMID: 15749491 DOI: 10.1016/j.fertnstert.2004.07.976] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 07/30/2004] [Accepted: 07/30/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To identify and understand predictors of successful varicocelectomy. DESIGN Examination of testicular L-type voltage-dependent calcium channel (L-VDCC) mRNAs and proteins in testis biopsies and comparison of presence and absence of various mRNAs with testicular cadmium levels, with apoptosis, and with sperm count change after varicocelectomy. SETTING University clinical urology practice and research laboratories. PATIENT(S) Infertile men with varicocele (left varicocele only, n = 18; bilateral varicoceles, n = 26) and controls (men with obstructive azoospermia undergoing testicular sperm extraction before intracytoplasmic sperm injection; n = 7). INTERVENTION(S) Left testis biopsies by percutaneous needle aspiration biopsy. Varicocele repair by subinguinal approach. MAIN OUTCOME MEASURE(S) Calcium channel mRNA sequence by reverse transcription-polymerase chain reaction and amplicon analysis; calcium channel protein distribution by immunocytochemistry; cadmium levels by atomic absorption and apoptosis by deoxynucleotidyl transferase labeling; and sperm counts in the ejaculate before and after varicocelectomy. RESULT(S) Calcium channel mRNAs are polymorphic in human testis biopsies from different men. Proteins from sequence-deleted exons 7 and/or 8 localize to germ cell membranes. Expression of undeleted L-type calcium channel mRNAs correlates with normal testes cadmium and increased sperm count after varicocelectomy. Apoptosis is lower in such cases. CONCLUSION(S) Expression of normal testicular L-VDCC sequence in exons 7-8 predicts postvaricocelectomy sperm count increase. Deletions may alter calcium channel function and affect testicular cadmium and apoptosis.
Collapse
Affiliation(s)
- Susan Benoff
- Fertility Research Laboratories, North Shore-Long Island Jewish Research Institute, North Shore University Hospital, Manhasset, New York, USA
| | | | | | | | | | | |
Collapse
|
45
|
Finlin BS, Mosley AL, Crump SM, Correll RN, Ozcan S, Satin J, Andres DA. Regulation of L-type Ca2+ channel activity and insulin secretion by the Rem2 GTPase. J Biol Chem 2005; 280:41864-71. [PMID: 15728182 DOI: 10.1074/jbc.m414261200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Voltage-dependent calcium (Ca2+) channels are involved in many specialized cellular functions and are controlled by a diversity of intracellular signals. Recently, members of the RGK family of small GTPases (Rem, Rem2, Rad, Gem/Kir) have been identified as novel contributors to the regulation of L-type calcium channel activity. In this study, microarray analysis of the mouse insulinoma MIN6 cell line revealed that the transcription of Rem2 gene is strongly induced by exposure to high glucose, which was confirmed by real-time reverse transcriptase-PCR and RNase protection analysis. Because elevation of intracellular Ca2+ in pancreatic beta-cells is essential for insulin secretion, we tested the hypothesis that Rem2 attenuates Ca2+ currents to regulate insulin secretion. Co-expression of Rem2 with CaV 1.2 or CaV1.3 L-type Ca + channels in a heterologous expression system completely inhibits de novo Ca2+ current expression. In addition, ectopic overexpression of Rem2 both inhibited L-type Ca2+ channel activity and prevented glucose-stimulated insulin secretion in pancreatic beta-cell lines. Co-immunoprecipitation studies demonstrate that Rem2 associates with a variety of CaVbeta subunits. Importantly, surface biotinylation studies demonstrate that the membrane distribution of Ca2+ channels was not reduced at a time when channel activity was potently inhibited by Rem2 expression, indicating that Rem2 modulates channel function without interfering with membrane trafficking. Taken together, these data suggest that inhibition of L-type Ca2+ channels by Rem2 signaling may represent a new and potentially important mechanism for regulating Ca2+-triggered exocytosis in hormone-secreting cells, including insulin secretion in pancreatic beta-cells.
Collapse
Affiliation(s)
- Brian S Finlin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, College of Medicine, Lexington, Kentucky 40536, USA
| | | | | | | | | | | | | |
Collapse
|
46
|
Parkash J, Chaudhry MA, Rhoten WB. Tumor necrosis factor-α-induced changes in insulin-producing β-cells. ACTA ACUST UNITED AC 2005; 286:982-93. [PMID: 16114068 DOI: 10.1002/ar.a.20229] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The migration of macrophages and lymphocytes that produce cytokines such as tumor necrosis factor-alpha (TNF-alpha) causes beta-cell death, leading to type 1 diabetes. Similarly, in type 2 diabetes, the adipocyte-derived cytokines including TNF-alpha are elevated in the circulation, causing inflammation and insulin resistance. Thus, the studies described in this article using TNF-alpha are relevant to furthering our understanding of the pathogenesis of diabetes mellitus. We used RINr1046-38 (RIN) insulin-producing beta-cells, which constitutively express calbindin-D(28k), to characterize the effect of TNF-alpha on apoptosis, replication, insulin release, and gene and protein expression. Western blots of TNF-alpha-treated RIN cells revealed a decrease in calbindin-D(28k). By ELISA, TNF-alpha-treated beta-cells had 47% less calbindin-D(28k) than controls. In association with the decline in calbindin-D(28k), TNF-alpha treatment of RIN cells led to a 73% greater increase in changes in intracellular calcium concentration (Delta[Ca(2+)](i)) in TNF-alpha-treated cells as compared to that in control RIN cells upon treatment with 50 mM KCl; caused a greater increase in the [Ca(2+)](i) following the addition of 5.5 microM ionomycin; increased by more than threefold the apoptotic rate, expressed as the percentage of TUNEL-positive nuclei to total nuclei; decreased the rate of cell replication by 36%; and increased and decreased selectively the expression of specific genes as determined by microarray analysis. The subcellular localizations of Bcl-2, an antiapoptotic protein, and Bax, a proapoptotic protein, within RIN cells were altered with TNF-alpha treatment such that the two were colocalized with mitochondria in the perinuclear region. We conclude that the proapoptotic action of TNF-alpha on beta-cells is manifested via decreased expression of calbindin-D(28k) and is mediated at least in part by [Ca(2+)](i).
Collapse
Affiliation(s)
- Jai Parkash
- Joan C. Edwards School of Medicine, Department of Anatomy, Cell and Neurobiology, Marshall University, Huntington, West Virginia 25704, USA.
| | | | | |
Collapse
|
47
|
Abstract
The beta-cell is equipped with at least six voltage-gated Ca2+ (CaV) channel alpha1-subunits designated CaV1.2, CaV1.3, CaV2.1, CaV2.2, CaV2.3, and CaV3.1. These principal subunits, together with certain auxiliary subunits, assemble into different types of CaV channels conducting L-, P/Q-, N-, R-, and T-type Ca2+ currents, respectively. The beta-cell shares customary mechanisms of CaV channel regulation with other excitable cells, such as protein phosphorylation, Ca2+-dependent inactivation, and G protein modulation. However, the beta-cell displays some characteristic features to bring these mechanisms into play. In islet beta-cells, CaV channels can be highly phosphorylated under basal conditions and thus marginally respond to further phosphorylation. In beta-cell lines, CaV channels can be surrounded by tonically activated protein phosphatases dominating over protein kinases; thus their activity is dramatically enhanced by inhibition of protein phosphatases. During the last 10 years, we have revealed some novel mechanisms of beta-cell CaV channel regulation under physiological and pathophysiological conditions, including the involvement of exocytotic proteins, inositol hexakisphosphate, and type 1 diabetic serum. This minireview highlights characteristic features of customary mechanisms of CaV channel regulation in beta-cells and also reviews our studies on newly identified mechanisms of beta-cell CaV channel regulation.
Collapse
Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Center for Diabetes Research, Karolinska Diabetes Center, Department of Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | | |
Collapse
|
48
|
Lee MS, Chang I, Kim S. Death effectors of beta-cell apoptosis in type 1 diabetes. Mol Genet Metab 2004; 83:82-92. [PMID: 15464423 DOI: 10.1016/j.ymgme.2004.08.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2004] [Revised: 07/31/2004] [Accepted: 08/03/2004] [Indexed: 01/15/2023]
Abstract
While it is generally agreed that apoptosis of pancreatic beta-cells is the most important and final step in the progression of type 1 diabetes without which clinical diabetes does not develop, it has not been elucidated which molecule(s) are the real culprit(s) in type 1 diabetes. Perforin, FasL, TNFalpha, IL-1, IFNgamma, and NO have been claimed as the effector molecules; however, they, as a single agent, might explain only part of beta-cell death in type 1 diabetes. While FasL was initially considered as a strong candidate for the most important death effector, following experiments cast doubt on such a hypothesis. Combinations or synergism between IFNgamma and TNFalpha or IL-1beta are being revisited as the death effectors, and molecular mechanism explaining such a synergism was addressed in several recent papers. The role of NF-kappaB for pancreatic beta-cell death in type 1 diabetes is also controversial. While NF-kappaB plays anti-apoptotic roles in most other death models, its role in type 1 diabetes might be different probably due to the involvement of multiple cytokines at different stages of the disease progression and the peculiarity of pancreatic beta-cells. Recent papers also suggested a role for Ca2+ in cytokine-mediated pancreatic beta-cell death. Such participation of Ca2+ in beta-cell death appears to have a close relevance to the mitochondrial events or ER stress that constitutes an important part of cell death machinery recently identified.
Collapse
Affiliation(s)
- Myung-Shik Lee
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong Kangnam-ku, Seoul 135-710, Republic of Korea.
| | | | | |
Collapse
|
49
|
Chang I, Cho N, Kim S, Kim JY, Kim E, Woo JE, Nam JH, Kim SJ, Lee MS. Role of calcium in pancreatic islet cell death by IFN-gamma/TNF-alpha. THE JOURNAL OF IMMUNOLOGY 2004; 172:7008-14. [PMID: 15153522 DOI: 10.4049/jimmunol.172.11.7008] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We studied the intracellular events associated with pancreatic beta cell apoptosis by IFN-gamma/TNF-alpha synergism. IFN-gamma/TNF-alpha treatment of MIN6N8 insulinoma cells increased the amplitude of high voltage-activated Ca(2+) currents, while treatment with IFN-gamma or TNF-alpha alone did not. Cytosolic Ca(2+) concentration ([Ca(2+)](c)) was also increased by IFN-gamma/TNF-alpha treatment. Blockade of L-type Ca(2+) channel by nifedipine abrogated death of insulinoma cells by IFN-gamma/TNF-alpha. Diazoxide that attenuates voltage-activated Ca(2+) currents inhibited MIN6N8 cell death by IFN-gamma/TNF-alpha, while glibenclamide that accentuates voltage-activated Ca(2+) currents augmented insulinoma cell death. A protein kinase C inhibitor attenuated MIN6N8 cell death and the increase in [Ca(2+)](c) by IFN-gamma/TNF-alpha. Following the increase in [Ca(2+)](c), calpain was activated, and calpain inhibitors decreased insulinoma cell death by IFN-gamma/TNF-alpha. As a downstream of calpain, calcineurin was activated and the inhibition of calcineurin activation by FK506 diminished insulinoma cell death by IFN-gamma/TNF-alpha. BAD phosphorylation was decreased by IFN-gamma/TNF-alpha because of the increased calcineurin activity, which was reversed by FK506. IFN-gamma/TNF-alpha induced cytochrome c translocation from mitochondria to cytoplasm and activation of caspase-9. Effector caspases such as caspase-3 or -7 were also activated by IFN-gamma/TNF-alpha treatment. These results indicate that IFN-gamma/TNF-alpha synergism induces pancreatic beta cell apoptosis by Ca(2+) channel activation followed by downstream intracellular events such as mitochondrial events and caspase activation and also suggest the therapeutic potential of Ca(2+) modulation in type 1 diabetes.
Collapse
Affiliation(s)
- Inik Chang
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Juntti-Berggren L, Refai E, Appelskog I, Andersson M, Imreh G, Dekki N, Uhles S, Yu L, Griffiths WJ, Zaitsev S, Leibiger I, Yang SN, Olivecrona G, Jörnvall H, Berggren PO. Apolipoprotein CIII promotes Ca2+-dependent beta cell death in type 1 diabetes. Proc Natl Acad Sci U S A 2004; 101:10090-4. [PMID: 15210953 PMCID: PMC454169 DOI: 10.1073/pnas.0403551101] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In type 1 diabetes (T1D), there is a specific destruction of the insulin secreting pancreatic beta cell. Although the exact molecular mechanisms underlying beta cell destruction are not known, sera from T1D patients have been shown to promote Ca(2+)-induced apoptosis. We now demonstrate that apolipoprotein CIII (apoCIII) is increased in serum from T1D patients and that this serum factor both induces increased cytoplasmic free intracellular Ca(2+) concentration ([Ca(2+)](i)) and beta cell death. The apoCIII-induced increase in [Ca(2+)](i) reflects an activation of the voltage-gated L-type Ca(2+) channel. Both the effects of T1D sera and apoCIII on the beta cell are abolished in the presence of antibody against apoCIII. Increased serum levels of apoCIII can thus account for the increase in beta cell [Ca(2+)](i) and thereby beta cell apoptosis associated with T1D.
Collapse
Affiliation(s)
- Lisa Juntti-Berggren
- Department of Molecular Medicine, Rolf Luft Center for Diabetes Research, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|