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Dei-Adomakoh YA, Akpalu J, Yawson AE, Ekem I, Reynolds M, Atiase Y. Steroid-induced dysglycaemia in patients with haematological disorders a ten-year review in a tertiary hospital in Ghana. Ghana Med J 2019; 53:156-162. [PMID: 31481812 PMCID: PMC6697763 DOI: 10.4314/gmj.v53i2.11] [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] [Indexed: 11/30/2022] Open
Abstract
Background Glucocorticoids (steroids) play a key role in the management of multiple medical conditions including haematological disorders. This study looked at the prevalence of steroid induced dysglycaemia in patients with haematological disorders receiving steroids as part of their treatment with the view of modifying its use and selection of patients where necessary. Methods A retrospective review of haematology patients on treatment regimens including steroids. Information extracted included, demographic characteristics, clinical information such as age, gender, haematological disorder, type of steroid, daily and cumulative dose of steroid, duration of therapy, family history of diabetes and alcohol use. Results The case records of 351 haematology patients were reviewed. However, eight patients with dysglycaemia before therapy were excluded. The median age of patients was 51.0 ± 26.0(IQR: Interquartile Range) years, with an age range of 13 to 87 years, and a female: male ratio of 1.2: 1 (p= 0.778). The prevalence of Steroid-Induced Dysglycaemia (SID) was 3.79% with a mean diagnosis interval of 8.8 + 2.1 months. Overall, 245 (71.4%) patients were on continuous steroids. Among the 13 patients who developed SID, 11 (84.6%) were on continuous steroids. In the majority of the patients (97.1%) there was no family history of diabetes in a first degree relative. Significant differences were found between patients with normoglycaemia and those with dysglycaemia with respect to age (p=0.049) and duration of steroid therapy (p=0.024). Conclusion The prevalence of steroid-induced dysglycaemia is relatively low among Ghanaian patients with haematological disorders on steroid based chemotherapy. Funding None declared
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Affiliation(s)
| | - Josephine Akpalu
- Korle Bu teaching hospital, Department of Medicine, Accra, Ghana
| | - Alfred E Yawson
- University of Ghana Medical School, Department of Community, Accra, Ghana.,National AIDS/STI Control Program, Clinical Care Unit, Ghana Health Service, Accra, Ghana
| | - Ivy Ekem
- University of Cape Coast, CoHAS, School of Medical Sciences, Department of Haematology, UCC SMS University of Cape Coast Cape Coast, Cape Coast
| | | | - Yacoba Atiase
- Korle Bu teaching hospital, Department of Medicine, Accra, Ghana
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Hasni Ebou M, Singh-Estivalet A, Launay JM, Callebert J, Tronche F, Ferré P, Gautier JF, Guillemain G, Bréant B, Blondeau B, Riveline JP. Glucocorticoids Inhibit Basal and Hormone-Induced Serotonin Synthesis in Pancreatic Beta Cells. PLoS One 2016; 11:e0149343. [PMID: 26901633 PMCID: PMC4763453 DOI: 10.1371/journal.pone.0149343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/29/2016] [Indexed: 12/31/2022] Open
Abstract
Diabetes is a major complication of chronic Glucocorticoids (GCs) treatment. GCs induce insulin resistance and also inhibit insulin secretion from pancreatic beta cells. Yet, a full understanding of this negative regulation remains to be deciphered. In the present study, we investigated whether GCs could inhibit serotonin synthesis in beta cell since this neurotransmitter has been shown to be involved in the regulation of insulin secretion. To this aim, serotonin synthesis was evaluated in vitro after treatment with GCs of either islets from CD1 mice or MIN6 cells, a beta-cell line. We also explored the effect of GCs on the stimulation of serotonin synthesis by several hormones such as prolactin and GLP 1. We finally studied this regulation in islet in two in vivo models: mice treated with GCs and with liraglutide, a GLP1 analog, and mice deleted for the glucocorticoid receptor in the pancreas. We showed in isolated islets and MIN6 cells that GCs decreased expression and activity of the two key enzymes of serotonin synthesis, Tryptophan Hydroxylase 1 (Tph1) and 2 (Tph2), leading to reduced serotonin contents. GCs also blocked the induction of serotonin synthesis by prolactin or by a previously unknown serotonin activator, the GLP-1 analog exendin-4. In vivo, activation of the Glucagon-like-Peptide-1 receptor with liraglutide during 4 weeks increased islet serotonin contents and GCs treatment prevented this increase. Finally, islets from mice deleted for the GR in the pancreas displayed an increased expression of Tph1 and Tph2 and a strong increased serotonin content per islet. In conclusion, our results demonstrate an original inhibition of serotonin synthesis by GCs, both in basal condition and after stimulation by prolactin or activators of the GLP-1 receptor. This regulation may contribute to the deleterious effects of GCs on beta cells.
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Affiliation(s)
- Moina Hasni Ebou
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Amrit Singh-Estivalet
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Jean-Marie Launay
- INSERM U942, Assistance Publique–Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Service de Biochimie, Paris, France
| | - Jacques Callebert
- INSERM U942, Assistance Publique–Hôpitaux de Paris (AP-HP), Hôpital Lariboisière, Service de Biochimie, Paris, France
| | - François Tronche
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- CNRS UMR INSERM 952-CNRS 7224, Paris, France
| | - Pascal Ferré
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Jean-François Gautier
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Department of Diabetes and Endocrinology, Hôpital Lariboisière, AP-HP, Paris, France
- Université Paris Diderot, Paris, France
| | - Ghislaine Guillemain
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Bernadette Bréant
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Bertrand Blondeau
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- * E-mail:
| | - Jean-Pierre Riveline
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Sorbonne Universités, UPMC, Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
- Department of Diabetes and Endocrinology, Hôpital Lariboisière, AP-HP, Paris, France
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Zhang C, Li L, Zhao B, Jiao A, Li X, Sun N, Zhang J. Ghrelin Protects against Dexamethasone-Induced INS-1 Cell Apoptosis via ERK and p38MAPK Signaling. Int J Endocrinol 2016; 2016:4513051. [PMID: 27190513 PMCID: PMC4844876 DOI: 10.1155/2016/4513051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 03/10/2016] [Accepted: 03/23/2016] [Indexed: 11/17/2022] Open
Abstract
Glucocorticoid excess induces apoptosis of islet cells, which may result in diabetes. In this study, we investigated the protective effect of ghrelin on dexamethasone-induced INS-1 cell apoptosis. Our data showed that ghrelin (0.1 μM) inhibited dexamethasone-induced (0.1 μM) apoptosis of INS-1 cells and facilitated cell proliferation. Moreover, ghrelin upregulated Bcl-2 expression, downregulated Bax expression, and decreased caspase-3 activity. The protective effect of ghrelin against dexamethasone-induced INS-1 cell apoptosis was mediated via growth hormone secretagogue receptor 1a. Further studies revealed that ghrelin increased ERK activation and decreased p38MAPK expression after dexamethasone treatment. Ghrelin-mediated protection of dexamethasone-induced apoptosis of INS-1 cells was attenuated using the ERK inhibitor U0126 (10 μM), and cell viability increased using the p38MAPK inhibitor SB203580 (10 μM). In conclusion, ghrelin could protect against dexamethasone-induced INS-1 cell apoptosis, at least partially via GHS-R1a and the signaling pathway of ERK and p38MAPK.
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Affiliation(s)
- Chengshuo Zhang
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, First Hospital of China Medical University, Shenyang 110001, China
| | - Le Li
- Hepatobiliary Surgery Department, Chifeng Municipal Hospital, Chifeng 024000, China
| | - Bochao Zhao
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, First Hospital of China Medical University, Shenyang 110001, China
| | - Ao Jiao
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, First Hospital of China Medical University, Shenyang 110001, China
| | - Xin Li
- Department of General Surgery, Fourth Hospital of China Medical University, Shenyang 110032, China
| | - Ning Sun
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, First Hospital of China Medical University, Shenyang 110001, China
| | - Jialin Zhang
- Hepatobiliary Surgery Department and Unit of Organ Transplantation, First Hospital of China Medical University, Shenyang 110001, China
- *Jialin Zhang:
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Chowdhury S, Grimm L, Gong YJK, Wang B, Li B, Srikant CB, Gao ZH, Liu JL. Decreased 11β-Hydroxysteroid Dehydrogenase 1 Level and Activity in Murine Pancreatic Islets Caused by Insulin-Like Growth Factor I Overexpression. PLoS One 2015; 10:e0136656. [PMID: 26305481 PMCID: PMC4549276 DOI: 10.1371/journal.pone.0136656] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 08/06/2015] [Indexed: 12/21/2022] Open
Abstract
We have reported a high expression of IGF-I in pancreatic islet β-cells of transgenic mice under the metallothionein promoter. cDNA microarray analysis of the islets revealed that the expression of 82 genes was significantly altered compared to wild-type mice. Of these, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), which is responsible for the conversion of inert cortisone (11-dehydrocorticosterone, DHC in rodents) to active cortisol (corticosterone) in the liver and adipose tissues, has not been identified previously as an IGF-I target in pancreatic islets. We characterized the changes in its protein level, enzyme activity and glucose-stimulated insulin secretion. In freshly isolated islets, the level of 11β-HSD1 protein was significantly lower in MT-IGF mice. Using dual-labeled immunofluorescence, 11β-HSD1 was observed exclusively in glucagon-producing, islet α-cells but at a lower level in transgenic vs. wild-type animals. MT-IGF islets also exhibited reduced enzymatic activities. Dexamethasone (DEX) and DHC inhibited glucose-stimulated insulin secretion from freshly isolated islets of wild-type mice. In the islets of MT-IGF mice, 48-h pre-incubation of DEX caused a significant decrease in insulin release, while the effect of DHC was largely blunted consistent with diminished 11β-HSD1 activity. In order to establish the function of intracrine glucocorticoids, we overexpressed 11β-HSD1 cDNA in MIN6 insulinoma cells, which together with DHC caused apoptosis and a significant decrease in proliferation. Both effects were abolished with the treatment of an 11β-HSD1 inhibitor. Our results demonstrate an inhibitory effect of IGF-I on 11β-HSD1 expression and activity within the pancreatic islets, which may mediate part of the IGF-I effects on cell proliferation, survival and insulin secretion.
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Affiliation(s)
- Subrata Chowdhury
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Larson Grimm
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Ying Jia Kate Gong
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Beixi Wang
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Bing Li
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Coimbatore B. Srikant
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Zu-hua Gao
- Department of Pathology, the Research Institute of McGill University Health Centre, Montreal, Canada
| | - Jun-Li Liu
- Fraser Laboratories for Diabetes Research, Department of Medicine, the Research Institute of McGill University Health Centre, Montreal, Canada
- Montreal Diabetes Research Centre, Montreal, Canada
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5
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Dumortier O, Theys N, Ahn MT, Remacle C, Reusens B. Impairment of rat fetal beta-cell development by maternal exposure to dexamethasone during different time-windows. PLoS One 2011; 6:e25576. [PMID: 21991320 PMCID: PMC3184993 DOI: 10.1371/journal.pone.0025576] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 09/07/2011] [Indexed: 12/22/2022] Open
Abstract
Aim Glucocorticoids (GCs) take part in the direct control of cell lineage during the late phase of pancreas development when endocrine and exocrine cell differentiation occurs. However, other tissues such as the vasculature exert a critical role before that phase. This study aims to investigate the consequences of overexposure to exogenous glucocorticoids during different time-windows of gestation for the development of the fetal endocrine pancreas. Methods Pregnant Wistar rats received dexamethasone acetate in their drinking water (1 µg/ml) during the last week or throughout gestation. Fetuses and their pancreases were analyzed at day 15 and 21 of gestation. Morphometrical analysis was performed on pancreatic sections after immunohistochemistry techniques and insulin secretion was evaluated on fetal islets collected in vitro. Results Dexamethasone given the last week or throughout gestation reduced the beta-cell mass in 21-day-old fetuses by respectively 18% or 62%. This was accompanied by a defect in insulin secretion. The alpha-cell mass was reduced similarly. Neither islet vascularization nor beta-cell proliferation was affected when dexamethasone was administered during the last week, which was however the case when given throughout gestation. When given from the beginning of gestation, dexamethasone reduced the number of cells expressing the early marker of endocrine lineage neurogenin-3 when analyzed at 15 days of fetal age. Conclusions GCs reduce the beta- and alpha-cell mass by different mechanisms according to the stage of development during which the treatment was applied. In fetuses exposed to glucocorticoids the last week of gestation only, beta-cell mass is reduced due to impairment of beta-cell commitment, whereas in fetuses exposed throughout gestation, islet vascularization and lower beta-cell proliferation are involved as well, amplifying the reduction of the endocrine mass.
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Affiliation(s)
- Olivier Dumortier
- Laboratoire de Biologie Cellulaire, Université catholique de Louvain, Institut des Sciences de la Vie, Louvain-la-Neuve, Belgium
| | - Nicolas Theys
- Laboratoire de Biologie Cellulaire, Université catholique de Louvain, Institut des Sciences de la Vie, Louvain-la-Neuve, Belgium
| | - Marie-Thérèse Ahn
- Laboratoire de Biologie Cellulaire, Université catholique de Louvain, Institut des Sciences de la Vie, Louvain-la-Neuve, Belgium
| | - Claude Remacle
- Laboratoire de Biologie Cellulaire, Université catholique de Louvain, Institut des Sciences de la Vie, Louvain-la-Neuve, Belgium
| | - Brigitte Reusens
- Laboratoire de Biologie Cellulaire, Université catholique de Louvain, Institut des Sciences de la Vie, Louvain-la-Neuve, Belgium
- * E-mail:
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6
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Ranta F, Avram D, Berchtold S, Düfer M, Drews G, Lang F, Ullrich S. Dexamethasone induces cell death in insulin-secreting cells, an effect reversed by exendin-4. Diabetes 2006; 55:1380-90. [PMID: 16644695 DOI: 10.2337/db05-1220] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Glucocorticoid excess induces hyperglycemia, which may result in diabetes. The present experiments explored whether glucocorticoids trigger apoptosis in insulin-secreting cells. Treatment of mouse beta-cells or INS-1 cells with the glucocorticoid dexamethasone (0.1 micromol/l) over 4 days in cell culture increased the number of fractionated nuclei from 2 to 7 and 14%, respectively, an effect that was reversed by the glucocorticoid receptor antagonist RU486 (1 micromol/l). In INS-1 cells, dexamethasone increased the number of transferase-mediated dUTP nick-end labeling-staining positive cells, caspase-3 activity, and poly-(ADP-) ribose polymerase protein cleavage; decreased Bcl-2 transcript and protein abundance; dephosphorylated the proapoptotic protein of the Bcl-2 family (BAD) at serine155; and depolarized mitochondria. Dexamethasone increased PP-2B (calcineurin) activity, an effect abrogated by FK506. FK506 (0.1 micromol/l) and another calcineurin inhibitor, deltamethrin (1 micromol/l), attenuated dexamethasone-induced cell death. The stable glucagon-like peptide 1 analog, exendin-4 (10 nmol/l), inhibited dexamethasone-induced apoptosis in mouse beta-cells and INS-1 cells. The protective effect of exendin-4 was mimicked by forskolin (10 micromol/l) but not mimicked by guanine nucleotide exchange factor with the specific agonist 8CPT-Me-cAMP (50 micromol/l). Exendin-4 did not protect against cell death in the presence of cAMP-dependent protein kinase (PKA) inhibition by H89 (10 micromol/l) or KT5720 (5 micromol/l). In conclusion, glucocorticoid-induced apoptosis in insulin-secreting cells is accompanied by a downregulation of Bcl-2, activation of calcineurin with subsequent dephosphorylation of BAD, and mitochondrial depolarization. Exendin-4 protects against glucocorticoid-induced apoptosis, an effect mimicked by forskolin and reversed by PKA inhibitors.
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Affiliation(s)
- Felicia Ranta
- Institut für Physiologie, University of Tübingen, Gmelinstrasse 5, D-72076 Tübingen, Germany
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Zhou F, Filipeanu CM, Duvernay MT, Wu G. Cell-surface targeting of alpha2-adrenergic receptors -- inhibition by a transport deficient mutant through dimerization. Cell Signal 2005; 18:318-27. [PMID: 15961277 PMCID: PMC2718052 DOI: 10.1016/j.cellsig.2005.05.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 05/04/2005] [Accepted: 05/04/2005] [Indexed: 01/08/2023]
Abstract
We previously demonstrated that the alpha2B-adrenergic receptor mutant, in which the F(x)6IL motif in the membrane-proximal carboxyl terminus were mutated to alanines (alpha2B-ARm), is deficient in export from the endoplasmic reticulum (ER). In this report, we determined if alpha2B-ARm could modulate transport from the ER to the cell surface and signaling of its wild-type counterpart. Transient expression of alpha2B-ARm in HEK293T cells markedly inhibited cell-surface expression of wild-type alpha2B-AR, as measured by radioligand binding. Subcellular localization demonstrated that alpha2B-ARm trapped alpha2B-AR in the ER. The alpha2B-AR was shown to form homodimers and heterodimers with alpha2B-ARm as measured by co-immunoprecipitation of the receptors tagged with green fluorescent protein and hemagglutinin epitopes. In addition to alpha2B-AR, the transport of alpha2A-AR and alpha2C-AR to the cell surface was also inhibited by alpha2B-ARm. Furthermore, transient expression of alpha2B-ARm significantly reduced cell-surface expression of endogenous alpha2-AR in NG108-15 and HT29 cells. Consistent with its effect on alpha2-AR cell-surface expression, alpha2B-ARm attenuated alpha2A-AR- and alpha2B-AR-mediated ERK1/2 activation. These data demonstrated that the ER-retained mutant alpha2B-ARm conferred a dominant negative effect on the cell-surface expression of wild-type alpha2-AR, which is likely mediated through heterodimerization. These data indicate a crucial role of ER export in the regulation of cell-surface targeting and signaling of G protein-coupled receptors.
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Affiliation(s)
| | | | | | - Guangyu Wu
- Corresponding author. Tel.: +1 504 568 2236; fax: +1 504 568 2361. E-mail address: (G. Wu)
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Davani B, Portwood N, Bryzgalova G, Reimer MK, Heiden T, Ostenson CG, Okret S, Ahren B, Efendic S, Khan A. Aged transgenic mice with increased glucocorticoid sensitivity in pancreatic beta-cells develop diabetes. Diabetes 2004; 53 Suppl 1:S51-9. [PMID: 14749266 DOI: 10.2337/diabetes.53.2007.s51] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Glucocorticoids are diabetogenic hormones because they decrease glucose uptake, increase hepatic glucose production, and inhibit insulin release. To study the long-term effects of increased glucocorticoid sensitivity in beta-cells, we studied transgenic mice overexpressing the rat glucocorticoid receptor targeted to the beta-cells using the rat insulin I promoter. Here we report that these mice developed hyperglycemia both in the fed and the overnight-fasted states at 12-15 months of age. Progression from impaired glucose tolerance, previously observed in the same colony at the age of 3 months, to manifest diabetes was not associated with morphological changes or increased apoptosis in the beta-cells. Instead, our current results suggest that the development of diabetes is due to augmented inhibition of insulin secretion through alpha(2)-adrenergic receptors (alpha(2)-ARs). Thus, we found a significantly higher density of alpha(2)-ARs in the islets of transgenic mice compared with controls, based on binding studies with the alpha(2)-AR agonist UK 14304. Furthermore, incubation of islets with benextramine, a selective antagonist of the alpha(2)-AR, restored insulin secretion in response to glucose in isolated islets from transgenic mice, whereas it had no effect on control islets. These results indicate that the chronic enhancement of glucocorticoid signaling in pancreatic beta-cells results in hyperglycemia and impaired glucose tolerance. This effect may involve signaling pathways that participate in the regulation of insulin secretion via the alpha(2)-AR.
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Affiliation(s)
- Behrous Davani
- Department of Molecular Medicine, Karolinska Hospital, Stockholm, Sweden.
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Karlsson S, Scheurink AJW, Ahrén B. Gender difference in the glucagon response to glucopenic stress in mice. Am J Physiol Regul Integr Comp Physiol 2002; 282:R281-8. [PMID: 11742849 DOI: 10.1152/ajpregu.2002.282.1.r281] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A gender difference in the glucagon response to insulin-induced hypoglycemia was previously demonstrated in humans. Whether this reflects a gender difference in autonomic activation or in pancreatic alpha-cell regulation is not known. We investigated the glucagon, epinephrine, and norepinephrine responses to neuroglycopenic stress induced by 2-deoxy-D-glucose (2-DG) or insulin in female and male mice. 2-DG increased plasma glucagon levels by 559 +/- 68% in females versus 281 +/- 46% in males (P < 0.01). Plasma levels of epinephrine or norepinephrine after 2-DG administration did not differ between genders. During insulin-induced hypoglycemia, the glucagon response was similarly higher in females (P < 0.001), whereas the plasma catecholamine response was higher in males (P < 0.05). In vivo, the glucagon response to carbachol or clonidine was higher in females (P < 0.05). In isolated islets, the glucagon response to carbachol (100 microM; P = 0.003) but not to clonidine (1 microM) was larger in females. We conclude that in addition to a larger alpha-cell mass (previously described in female mice), an increased sensitivity of the glucagon-producing alpha-cell to cholinergic activation contributes to the larger glucagon response to glucopenic stress in female mice.
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Affiliation(s)
- Sven Karlsson
- Department of Medicine, Lund University, SE-221 84 Lund, Sweden.
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10
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Delaunay F, Khan A, Cintra A, Davani B, Ling ZC, Andersson A, Ostenson CG, Gustafsson J, Efendic S, Okret S. Pancreatic beta cells are important targets for the diabetogenic effects of glucocorticoids. J Clin Invest 1997; 100:2094-8. [PMID: 9329975 PMCID: PMC508401 DOI: 10.1172/jci119743] [Citation(s) in RCA: 223] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Abnormalities contributing to the pathogenesis of non-insulin-dependent diabetes mellitus include impaired beta cell function, peripheral insulin resistance, and increased hepatic glucose production. Glucocorticoids are diabetogenic hormones because they decrease glucose uptake and increase hepatic glucose production. In addition, they may directly inhibit insulin release. To evaluate that possible role of glucocorticoids in beta cell function independent of their other effects, transgenic mice with an increased glucocorticoid sensitivity restricted to their beta cells were generated by overexpressing the glucocorticoid receptor (GR) under the control of the insulin promoter. Intravenous glucose tolerance tests showed that the GR transgenic mice had normal fasting and postabsorptive blood glucose levels but exhibited a reduced glucose tolerance compared with their control littermates. Measurement of plasma insulin levels 5 min after intravenous glucose load demonstrated a dramatic decrease in acute insulin response in the GR transgenic mice. These results show that glucocorticoids directly inhibit insulin release in vivo and identify the pancreatic beta cell as an important target for the diabetogenic action of glucocorticoids.
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Affiliation(s)
- F Delaunay
- Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital, S-141 86 Huddinge, Sweden.
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Lambillotte C, Gilon P, Henquin JC. Direct glucocorticoid inhibition of insulin secretion. An in vitro study of dexamethasone effects in mouse islets. J Clin Invest 1997; 99:414-23. [PMID: 9022074 PMCID: PMC507814 DOI: 10.1172/jci119175] [Citation(s) in RCA: 279] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The direct effects of glucocorticoids on pancreatic beta cell function were studied with normal mouse islets. Dexamethasone inhibited insulin secretion from cultured islets in a concentration-dependent manner: maximum of approximately 75% at 250 nM and IC50 at approximately 20 nM dexamethasone. This inhibition was of slow onset (0, 20, and 40% after 1, 2, and 3 h) and only slowly reversible. It was prevented by a blocker of nuclear glucocorticoid receptors, by pertussis toxin, by a phorbol ester, and by dibutyryl cAMP, but was unaffected by an increase in the fuel content of the culture medium. Dexamethasone treatment did not affect islet cAMP levels but slightly reduced inositol phosphate formation. After 18 h of culture with or without 1 microM dexamethasone, the islets were perifused and stimulated by a rise in the glucose concentration from 3 to 15 mM. Both phases of insulin secretion were similarly decreased in dexamethasone-treated islets as compared with control islets. This inhibition could not be ascribed to a lowering of insulin stores (higher in dexamethasone-treated islets), to an alteration of glucose metabolism (glucose oxidation and NAD(P)H changes were unaffected), or to a lesser rise of cytoplasmic Ca2+ in beta cells (only the frequency of the oscillations was modified). Dexamethasone also inhibited insulin secretion induced by arginine, tolbutamide, or high K+. In this case also the inhibition was observed despite a normal rise of cytoplasmic Ca2+. In conclusion, dexamethasone inhibits insulin secretion through a genomic action in beta cells that leads to a decrease in the efficacy of cytoplasmic Ca2+ on the exocytotic process.
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Affiliation(s)
- C Lambillotte
- Unité d'Endocrinologie et Métabolisme, University of Louvain Faculty of Medicine, Brussels, Belgium
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