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Berger I, Werdermann M, Bornstein SR, Steenblock C. The adrenal gland in stress - Adaptation on a cellular level. J Steroid Biochem Mol Biol 2019; 190:198-206. [PMID: 30959152 DOI: 10.1016/j.jsbmb.2019.04.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/15/2019] [Accepted: 04/05/2019] [Indexed: 01/29/2023]
Abstract
Human individuals are constantly confronted to various kinds of stressors and the body's response and adaptation is essential for human health. The adrenal gland as the main producer of stress hormones plays a major role in the response to physiological challenges and is able to adapt to these physiological needs. Proper adaptation is of particular importance since dysregulation of the stress system is the cause of various human diseases including obesity, depression, Parkinson's disease, and post-traumatic stress disorder. Therefore, it is fundamental to understand the physiological, cellular, and molecular underpinnings of the stress adaptation in humans. Because of ethical reasons it is problematic to study the plasticity of the human gland in stress. Hence, various experimental models have been established for the analysis of the functional and cellular role of the adrenal gland adaptation on a translational approach. Here, we summarize the insights of stress-induced adrenal plasticity gained from these models and discuss their relevance to clinical observations.
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Affiliation(s)
- Ilona Berger
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Martin Werdermann
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Stefan R Bornstein
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; Diabetes and Nutritional Sciences Division, King's College London, London WC2R 2LS, UK
| | - Charlotte Steenblock
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany.
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Koniari I, Tzanis G, Tsigkas G, Soufras G, Hahalis G, Kounis N. Attacking the ATAK Complex in Cardiac Anesthesia. J Cardiothorac Vasc Anesth 2017; 31:e89-e91. [DOI: 10.1053/j.jvca.2016.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Indexed: 11/11/2022]
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Koniari I, Kounis NG, Soufras GD, Hahalis G. Takotsubo syndrome: Does it matter if you have diabetes mellitus? The need of new therapeutic modalities. Int J Cardiol 2017; 229:38. [DOI: 10.1016/j.ijcard.2016.11.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 10/05/2016] [Accepted: 11/16/2016] [Indexed: 10/20/2022]
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Deng M, Tufan T, Raza MU, Jones TC, Zhu MY. MicroRNAs 29b and 181a down-regulate the expression of the norepinephrine transporter and glucocorticoid receptors in PC12 cells. J Neurochem 2016; 139:197-207. [PMID: 27501468 DOI: 10.1111/jnc.13761] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/25/2016] [Accepted: 08/01/2016] [Indexed: 12/13/2022]
Abstract
MicroRNAs are short non-coding RNAs that provide global regulation of gene expression at the post-transcriptional level. Such regulation has been found to play a role in stress-induced epigenetic responses in the brain. The norepinephrine transporter (NET) and glucocorticoid receptors are closely related to the homeostatic integration and regulation after stress. Our previous studies demonstrated that NET mRNA and protein levels in rats are regulated by chronic stress and by administration of corticosterone, which is mediated through glucocorticoid receptors. Whether miRNAs are intermediaries in the regulation of these proteins remains to be elucidated. This study was undertaken to determine possible regulatory effects of miRNAs on the expression of NET and glucocorticoid receptors in the noradrenergic neuronal cell line. Using computational target prediction, we identified several candidate miRNAs potentially targeting NET and glucocorticoid receptors. Western blot results showed that over-expression of miR-181a and miR-29b significantly repressed protein levels of NET, which is accompanied by a reduced [3 H] norepinephrine uptake, and glucocorticoid receptors in PC12 cells. Luciferase reporter assays verified that both miR-181a and miR-29b bind the 3'UTR of mRNA of NET and glucocorticoid receptors. Furthermore, exposure of PC12 cells to corticosterone markedly reduced the endogenous levels of miR-29b, which was not reversed by the application of glucocorticoid receptor antagonist mifepristone. These observations indicate that miR-181a and miR-29b can function as the negative regulators of NET and glucocorticoid receptor translation in vitro. This regulatory effect may be related to stress-induced up-regulation of the noradrenergic phenotype, a phenomenon observed in stress models and depressive patients. This study demonstrated that miR-29b and miR-181a, two short non-coding RNAs that provide global regulation of gene expression, markedly repressed protein levels of norepinephrine (NE) transporter and glucocorticoid receptor (GR), as well as NE uptake by binding the 3'UTR of their mRNAs in PC12 cells. Also, exposure of cells to corticosterone significantly reduced miR-29b levels through a GR-independent way.
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Affiliation(s)
- Maoxian Deng
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA.,Department of Veterinary Medicine and Animal Husbandry, Jiangsu Polytechnic College of A&F, Jurong, Jiangsu, China
| | - Turan Tufan
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Muhammad U Raza
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Thomas C Jones
- Department of Biological Sciences, College of Arts and Sciences, East Tennessee State University, Johnson City, Tennessee, USA
| | - Meng-Yang Zhu
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA.
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Mechanisms of cortisol action in fish hepatocytes. Comp Biochem Physiol B Biochem Mol Biol 2016; 199:136-145. [DOI: 10.1016/j.cbpb.2016.06.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/21/2016] [Accepted: 06/27/2016] [Indexed: 12/17/2022]
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Radhakutty A, Mangelsdorf BL, Drake SM, Samocha-Bonet D, Jenkins AB, Heilbronn LK, Smith MD, Thompson CH, Burt MG. Effect of acute and chronic glucocorticoid therapy on insulin sensitivity and postprandial vascular function. Clin Endocrinol (Oxf) 2016; 84:501-8. [PMID: 26493042 DOI: 10.1111/cen.12966] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/15/2015] [Accepted: 10/19/2015] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Postprandial hyperglycaemia is associated with increased arterial stiffness and cardiovascular events. Low-dose prednisolone causes insulin resistance that typically manifests as postprandial hyperglycaemia. We investigated whether prednisolone causes postprandial vascular dysfunction in a cohort of patients with rheumatoid arthritis. DESIGN An open interventional and cross-sectional study was undertaken. PATIENTS AND MEASUREMENTS Eighteen subjects with rheumatoid arthritis who had not taken oral glucocorticoids for ≥6 months were studied before and after prednisolone 6 mg/day for 7 days to determine the acute effects of prednisolone. Pre-prednisolone data were compared to 18 subjects with rheumatoid arthritis taking long-term (>6 months) prednisolone (6·5 ± 1·8 mg/day) to assess the chronic effects of prednisolone. Augmentation index (by applanation tonometry) and reactive hyperaemia index (by peripheral artery tonometry) were measured before and after a mixed-meal (10 kcal/kg, 45% carbohydrate, 15% protein, 40% fat). Insulin sensitivity was estimated by the Matsuda index and sympathetic nervous system activity from urinary noradrenaline excretion. RESULTS Matsuda index was lower after acute (2·0 ± 1·0 vs 3·6 ± 1·1, P = 0·01) and chronic (1·9 ± 1·0 vs 3·6 ± 1·1, P = 0·04) prednisolone. Postprandial augmentation index was lower after acute prednisolone (2551 ± 197 vs 2690 ± 272%*min, P ≤ 0·001), but not chronic prednisolone. There were no significant differences in reactive hyperaemia index with acute or chronic prednisolone. Noradrenaline excretion was lower after acute (54 ± 8 vs 93 ± 23 nmol/6 h, P = 0·02), but not chronic, prednisolone. CONCLUSIONS Prednisolone-induced insulin resistance is not associated with postprandial vascular dysfunction in patients with rheumatoid arthritis. Reduced sympathetic activity may contribute to the reduction in postprandial arterial stiffness with acute prednisolone.
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Affiliation(s)
- Anjana Radhakutty
- School of Medicine, Flinders University, Adelaide, Australia
- Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, Australia
| | - Brenda L Mangelsdorf
- Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, Australia
| | - Sophie M Drake
- Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, Australia
| | - Dorit Samocha-Bonet
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia
| | - Arthur B Jenkins
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia
- School of Medicine, University of Wollongong, Wollongong, Australia
| | | | - Malcolm D Smith
- School of Medicine, Flinders University, Adelaide, Australia
- Department of Rheumatology, Repatriation General Hospital, Adelaide, Australia
| | - Campbell H Thompson
- School of Medicine, Flinders University, Adelaide, Australia
- Discipline of Medicine, The University of Adelaide, Adelaide, Australia
| | - Morton G Burt
- School of Medicine, Flinders University, Adelaide, Australia
- Southern Adelaide Diabetes and Endocrine Services, Repatriation General Hospital, Adelaide, Australia
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Deng Q, Riquelme D, Trinh L, Low MJ, Tomić M, Stojilkovic S, Aguilera G. Rapid Glucocorticoid Feedback Inhibition of ACTH Secretion Involves Ligand-Dependent Membrane Association of Glucocorticoid Receptors. Endocrinology 2015; 156:3215-27. [PMID: 26121342 PMCID: PMC4541620 DOI: 10.1210/en.2015-1265] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The hypothesis that rapid glucocorticoid inhibition of pituitary ACTH secretion mediates a feedforward/feedback mechanism responsible for the hourly glucocorticoid pulsatility was tested in cultured pituitary cells. Perifusion with 30 pM CRH caused sustained the elevation of ACTH secretion. Superimposed corticosterone pulses inhibited CRH-stimulated ACTH release, depending on prior glucocorticoid clearance. When CRH perifusion started after 2 hours of glucocorticoid-free medium, corticosterone levels in the stress range (1 μM) caused a delayed (25 min) and prolonged inhibition of CRH-stimulated ACTH secretion, up to 60 minutes after corticosterone withdrawal. In contrast, after 6 hours of glucocorticoid-free medium, basal corticosterone levels inhibited CRH-stimulated ACTH within 5 minutes, after rapid recovery 5 minutes after corticosterone withdrawal. The latter effect was insensitive to actinomycin D but was prevented by the glucocorticoid receptor antagonist, RU486, suggesting nongenomic effects of the classical glucocorticoid receptor. In hypothalamic-derived 4B cells, 10 nM corticosterone increased immunoreactive glucocorticoid receptor content in membrane fractions, with association and clearance rates paralleling the effects on ACTH secretion from corticotrophs. Corticosterone did not affect CRH-stimulated calcium influx, but in AtT-20 cells, it had biphasic effects on CRH-stimulated Src phosphorylation, with early inhibition and late stimulation, suggesting a role for Src phosphorylation on the rapid glucocorticoid feedback. The data suggest that the nongenomic/membrane effects of classical GR mediate rapid and reversible glucocorticoid feedback inhibition at the pituitary corticotrophs downstream of calcium influx. The sensitivity and kinetics of these effects is consistent with the hypothesis that pituitary glucocorticoid feedback is part of the mechanism for adrenocortical ultradian pulse generation.
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Affiliation(s)
- Qiong Deng
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Denise Riquelme
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Loc Trinh
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Malcolm J Low
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Melanija Tomić
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Stanko Stojilkovic
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Greti Aguilera
- Sections on Endocrine Physiology (Q.D., D.R., L.T., G.A.) and Cellular Signaling (M.T., S.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892; College of Animal Sciences (Q.D.), Jilin University, Chang Chun 130021, China; and Department of Molecular and Integrative Physiology (M.J.L.), University of Michigan Medical School, Ann Arbor, Michigan 48109
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Watson ML, Baehr LM, Reichardt HM, Tuckermann JP, Bodine SC, Furlow JD. A cell-autonomous role for the glucocorticoid receptor in skeletal muscle atrophy induced by systemic glucocorticoid exposure. Am J Physiol Endocrinol Metab 2012; 302:E1210-20. [PMID: 22354783 PMCID: PMC3361985 DOI: 10.1152/ajpendo.00512.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glucocorticoids (GCs) are important regulators of skeletal muscle mass, and prolonged exposure will induce significant muscle atrophy. To better understand the mechanism of skeletal muscle atrophy induced by elevated GC levels, we examined three different models: exogenous synthetic GC treatment [dexamethasone (DEX)], nutritional deprivation, and denervation. Specifically, we tested the direct contribution of the glucocorticoid receptor (GR) in skeletal muscle atrophy by creating a muscle-specific GR-knockout mouse line (MGR(e3)KO) using Cre-lox technology. In MGR(e3)KO mice, we found that the GR is essential for muscle atrophy in response to high-dose DEX treatment. In addition, DEX regulation of multiple genes, including two important atrophy markers, MuRF1 and MAFbx, is eliminated completely in the MGR(e3)KO mice. In a condition where endogenous GCs are elevated, such as nutritional deprivation, induction of MuRF1 and MAFbx was inhibited, but not completely blocked, in MGR(e3)KO mice. In response to sciatic nerve lesion and hindlimb muscle denervation, muscle atrophy and upregulation of MuRF1 and MAFbx occurred to the same extent in both wild-type and MGR(e3)KO mice, indicating that a functional GR is not required to induce atrophy under these conditions. Therefore, we demonstrate conclusively that the GR is an important mediator of skeletal muscle atrophy and associated gene expression in response to exogenous synthetic GCs in vivo and that the MGR(e3)KO mouse is a useful model for studying the role of the GR and its target genes in multiple skeletal muscle atrophy models.
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Affiliation(s)
- Monica L Watson
- Dept. of Neurobiology, Physiology, and Behavior, Univ. of California, One Shields Ave., Davis, CA 95616-8519, USA
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Odermatt A, Kratschmar DV. Tissue-specific modulation of mineralocorticoid receptor function by 11β-hydroxysteroid dehydrogenases: an overview. Mol Cell Endocrinol 2012; 350:168-86. [PMID: 21820034 DOI: 10.1016/j.mce.2011.07.020] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 07/03/2011] [Accepted: 07/09/2011] [Indexed: 01/23/2023]
Abstract
In the last decade significant progress has been made in the understanding of mineralocorticoid receptor (MR) function and its implications for physiology and disease. The knowledge on the essential role of MR in the regulation of electrolyte concentrations and blood pressure has been significantly extended, and the relevance of excessive MR activation in promoting inflammation, fibrosis and heart disease as well as its role in modulating neuronal cell viability and brain function is now widely recognized. Despite considerable progress, the mechanisms of MR function in various cell-types are still poorly understood. Key modulators of MR function include the glucocorticoid receptor (GR), which may affect MR function by formation of heterodimers and by differential genomic and non-genomic responses on gene expression, and 11β-hydroxysteroid dehydrogenases (11β-HSDs), which determine the availability of intracellular concentrations of active glucocorticoids. In this review we attempted to provide an overview of the knowledge on MR expression with regard to the presence or absence of GR, 11β-HSD2 and 11β-HSD1/hexose-6-phosphate dehydrogenase (H6PDH) in various tissues and cell types. The consequences of cell-specific differences in the coexpression of MR with these proteins need to be further investigated in order to understand the role of this receptor in a given tissue as well as its systemic impact.
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Affiliation(s)
- Alex Odermatt
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, Basel, Switzerland.
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Jung YH, Kang DH, Byun MS, Shim G, Kwon SJ, Jang GE, Lee US, An SC, Jang JH, Kwon JS. Influence of brain-derived neurotrophic factor and catechol O-methyl transferase polymorphisms on effects of meditation on plasma catecholamines and stress. Stress 2012; 15:97-104. [PMID: 21790467 DOI: 10.3109/10253890.2011.592880] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Meditation may show differential effects on stress and plasma catecholamines based on genetic polymorphisms in brain-derived neurotrophic factor (BDNF) and catechol O-methyl transferase (COMT). Eighty adults (40 men, 40 women; mean age 26 years) who practiced meditation regularly and 57 healthy control adults (35 men, 22 women; mean age 26 years) participated. Plasma catecholamines (norepinephrine (NE), epinephrine (E), and dopamine (DA)) concentrations were measured, and a modified form of the Stress Response Inventory was administered. The results were analyzed using two-way analysis of covariance (ANCOVA) with control and meditation subjects, gene polymorphism as factors, and meditation duration as the covariate. Two-way ANCOVA showed a significant interaction between control and meditation subjects, and BDNF Val66Met polymorphism on DA/NE+DA/E (p = 0.042) and NE/E+NE/DA (p = 0.046) ratios. A significant interaction was found for control and meditation subjects with COMT Val158Met polymorphism and plasma NE concentrations (p = 0.009). Post hoc ANCOVA in the meditation group, adjusted for meditation duration, showed significantly higher plasma NE concentrations for COMT Met carriers than COMT Val/Val subjects (p = 0.025). Significant differences of stress levels were found between the control and meditation subjects in BDNF Val/Met (p < 0.001) and BDNF Met/Met (p = 0.003), whereas stress levels in the BDNF Val/Val genotype did not differ between the control and meditation groups. This is the first evidence that meditation produces different effects on plasma catecholamines according to BDNF or COMT polymorphisms.
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Affiliation(s)
- Ye-Ha Jung
- Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2009; 16:260-77. [PMID: 19390324 DOI: 10.1097/med.0b013e32832c937e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Park Y, Kim KT. Dominant role of lipid rafts L-type calcium channel in activity-dependent potentiation of large dense-core vesicle exocytosis. J Neurochem 2009; 110:520-9. [PMID: 19457106 DOI: 10.1111/j.1471-4159.2009.06148.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Calcium influx triggers exocytosis by promoting vesicle fusion with the plasma membrane. However, different subtypes of voltage-gated calcium channel (VGCC) have distinct roles in exocytosis. We previously reported that repetitive stimulation induces activity-dependent potentiation (ADP) which represents the increase of neurotransmitter release. Here, we show that L-type VGCC have a dominant role in ADP of large dense-core vesicle (LDCV) exocytosis. Repetitive stimulation activating VGCC can induce ADP, whereas activation of bradykinin (BK) G protein-coupled receptors or purinergic P2X cation channels can not. L-type VGCC has the dominant role in ADP of LDCV exocytosis by regulating Protein Kinase C (PKC)-epsilon translocation and phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS), a target molecule of PKC-epsilon. We provide evidence that L-type VGCC, PKC-epsilon, and MARCKS, but not Q-type VGCC, are selectively located in lipid rafts. Also, PKC-epsilon translocation induced by L-type VGCC activation occurs in lipid rafts. Disruption of lipid rafts abolishes ADP of LDCV exocytosis and changes the fusion pore kinetics without affecting the first stimulation-induced exocytosis, showing that lipid rafts are involved in the potentiation process. Taken together, we suggest that L-type VGCC in lipid rafts selectively mediates ADP of LDCV exocytosis by regulating PKC-epsilon translocation and MARCKS phosphorylation.
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Affiliation(s)
- Yongsoo Park
- Department of Life Science, Pohang University of Science and Technology, Korea
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