151
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Spiga F, Lightman SL. Dynamics of adrenal glucocorticoid steroidogenesis in health and disease. Mol Cell Endocrinol 2015; 408:227-34. [PMID: 25662280 DOI: 10.1016/j.mce.2015.02.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/03/2015] [Accepted: 02/03/2015] [Indexed: 12/21/2022]
Abstract
The activity of the hypothalamic-pituitary-adrenal (HPA) axis is characterized by an ultradian (pulsatile) pattern of hormone secretion. Pulsatility of glucocorticoids has been found critical for optimal transcriptional, neuroendocrine and behavioral responses. This review will focus on the mechanisms underlying the origin of the glucocorticoid ultradian rhythm. Our recent research shows that the ultradian rhythm of glucocorticoids depends on highly dynamic processes within adrenocortical steroidogenic cells. Furthermore, we have evidence that disruption of these dynamics leads to abnormal glucocorticoid secretion observed in disease and critical illness in both humans and rats.
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Affiliation(s)
- Francesca Spiga
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK.
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
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152
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Bahat A, Perlberg S, Melamed-Book N, Isaac S, Eden A, Lauria I, Langer T, Orly J. Transcriptional activation of LON Gene by a new form of mitochondrial stress: A role for the nuclear respiratory factor 2 in StAR overload response (SOR). Mol Cell Endocrinol 2015; 408:62-72. [PMID: 25724481 DOI: 10.1016/j.mce.2015.02.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 01/19/2023]
Abstract
High output of steroid hormone synthesis in steroidogenic cells of the adrenal cortex and the gonads requires the expression of the steroidogenic acute regulatory protein (StAR) that facilitates cholesterol mobilization to the mitochondrial inner membrane where the CYP11A1/P450scc enzyme complex converts the sterol to the first steroid. Earlier studies have shown that StAR is active while pausing on the cytosolic face of the outer mitochondrial membrane while subsequent import of the protein into the matrix terminates the cholesterol mobilization activity. Consequently, during repeated activity cycles, high level of post-active StAR accumulates in the mitochondrial matrix. To prevent functional damage due to such protein overload effect, StAR is degraded by a sequence of three to four ATP-dependent proteases of the mitochondria protein quality control system, including LON and the m-AAA membranous proteases AFG3L2 and SPG7/paraplegin. Furthermore, StAR expression in both peri-ovulatory ovarian cells, or under ectopic expression in cell line models, results in up to 3-fold enrichment of the mitochondrial proteases and their transcripts. We named this novel form of mitochondrial stress as StAR overload response (SOR). To better understand the SOR mechanism at the transcriptional level we analyzed first the unexplored properties of the proximal promoter of the LON gene. Our findings suggest that the human nuclear respiratory factor 2 (NRF-2), also known as GA binding protein (GABP), is responsible for 88% of the proximal promoter activity, including the observed increase of transcription in the presence of StAR. Further studies are expected to reveal if common transcriptional determinants coordinate the SOR induced transcription of all the genes encoding the SOR proteases.
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Affiliation(s)
- Assaf Bahat
- Department of Biological Chemistry at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shira Perlberg
- Department of Biological Chemistry at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Naomi Melamed-Book
- Bio-Imaging Unit at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Sara Isaac
- Department of Cell & Developmental Biology at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Amir Eden
- Department of Cell & Developmental Biology at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ines Lauria
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Thomas Langer
- CECAD Research Center, Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Joseph Orly
- Department of Biological Chemistry at the Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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153
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Castillo AF, Orlando U, Helfenberger KE, Poderoso C, Podesta EJ. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis. Mol Cell Endocrinol 2015; 408:73-9. [PMID: 25540920 DOI: 10.1016/j.mce.2014.12.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 12/16/2022]
Abstract
The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.
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Affiliation(s)
- Ana F Castillo
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ulises Orlando
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Katia E Helfenberger
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Cecilia Poderoso
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ernesto J Podesta
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina.
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154
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Bandulik S, Tauber P, Lalli E, Barhanin J, Warth R. Two-pore domain potassium channels in the adrenal cortex. Pflugers Arch 2015; 467:1027-42. [PMID: 25339223 PMCID: PMC4428839 DOI: 10.1007/s00424-014-1628-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 12/31/2022]
Abstract
The physiological control of steroid hormone secretion from the adrenal cortex depends on the function of potassium channels. The "two-pore domain K(+) channels" (K2P) TWIK-related acid sensitive K(+) channel 1 (TASK1), TASK3, and TWIK-related K(+) channel 1 (TREK1) are strongly expressed in adrenocortical cells. They confer a background K(+) conductance to these cells which is important for the K(+) sensitivity as well as for angiotensin II and adrenocorticotropic hormone-dependent stimulation of aldosterone and cortisol synthesis. Mice with single deletions of the Task1 or Task3 gene as well as Task1/Task3 double knockout mice display partially autonomous aldosterone synthesis. It appears that TASK1 and TASK3 serve different functions: TASK1 affects cell differentiation and prevents expression of aldosterone synthase in the zona fasciculata, while TASK3 controls aldosterone secretion in glomerulosa cells. TREK1 is involved in the regulation of cortisol secretion in fasciculata cells. These data suggest that a disturbed function of K2P channels could contribute to adrenocortical pathologies in humans.
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Affiliation(s)
- Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany,
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155
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Wang C, Ruan T, Liu J, He B, Zhou Q, Jiang G. Perfluorooctyl Iodide Stimulates Steroidogenesis in H295R Cells via a Cyclic Adenosine Monophosphate Signaling Pathway. Chem Res Toxicol 2015; 28:848-54. [PMID: 25871633 DOI: 10.1021/tx5004563] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Perfluorinated iodine alkanes (PFIs) are used widely in the organic fluorine industry. Increased production of PFIs has caused environmental health concerns. To evaluate the potential endocrine-disrupting effect of PFIs, we investigated the effects of perfluorooctyl iodide (PFOI) on steroidogenesis in human adrenocortical carcinoma cells (H295R). Levels of aldosterone, cortisol, 17β-estradiol, and testosterone were measured in H295R culture medium upon treatment with perfluorooctanoic acid (PFOA) and PFIs. Expression of 10 steroidogenic genes (StAR, HMGR, CYP11A1, 3βHSD2, 17βHSD, CYP17, CYP21, CYP11B1, CYP11B2, and CYP19) was measured by real-time polymerase chain reaction. Levels of cyclic adenosine monophosphate (cAMP) and adenylate cyclase (AC) activity were measured to understand the underlying mechanism of steroidogenic perturbations. Levels of production of aldosterone, cortisol, and 17β-estradiol were elevated significantly, and the level of testosterone generation decreased upon treatment with 100 μM PFOI. Similar to the effect induced by forskolin (AC activator), expression of all 10 genes involved in the synthesis of steroid hormones was upregulated significantly upon exposure to 100 μM PFOI. PFOA had no effect on steroid hormone production or steroidogenic gene expression even though it is highly structurally similar with PFOI. Therefore, the terminal -CF2I group in PFOI could be a critical factor for mediation of steroidogenesis. PFOI increased AC activity and cAMP levels in H295R cells, which implied an underlying mechanism for the disturbance of steroidogenesis. These data suggest that PFOI may act as an AC activator, thereby stimulating steroidogenesis by activating a cAMP signaling pathway.
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Affiliation(s)
- Chang Wang
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China.,‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Ting Ruan
- ‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Jiyan Liu
- ‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Bin He
- ‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Qunfang Zhou
- ‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Guibin Jiang
- ‡State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
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156
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Liu S, Zhang J, Li W, Zhang T, Hu D. Acteoside reduces testosterone by inhibiting cAMP, p450scc, and StAR in rat Leydig cells. Mol Cell Toxicol 2015. [DOI: 10.1007/s13273-015-0002-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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157
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Gibbison B, Spiga F, Walker JJ, Russell GM, Stevenson K, Kershaw Y, Zhao Z, Henley D, Angelini GD, Lightman SL. Dynamic pituitary-adrenal interactions in response to cardiac surgery. Crit Care Med 2015; 43:791-800. [PMID: 25517478 PMCID: PMC4359905 DOI: 10.1097/ccm.0000000000000773] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVES To characterize the dynamics of the pituitary-adrenal interaction during the course of coronary artery bypass grafting both on and off pump. Since our data pointed to a major change in adrenal responsiveness to adrenocorticotropic hormone, we used a reverse translation approach to investigate the molecular mechanisms underlying this change in a rat model of critical illness. DESIGN CLINICAL STUDIES Prospective observational study. ANIMAL STUDIES Controlled experimental study. SETTING CLINICAL STUDIES Cardiac surgery operating rooms and critical care units. ANIMAL STUDIES University research laboratory. SUBJECTS CLINICAL STUDIES Twenty, male patients. ANIMAL STUDIES Adult, male Sprague-Dawley rats. INTERVENTIONS CLINICAL STUDIES Coronary artery bypass graft-both on and off pump. ANIMAL STUDIES Injection of either lipopolysaccharide or saline (controls) via a jugular vein cannula. MEASUREMENTS AND MAIN RESULTS CLINICAL STUDIES Blood samples were taken for 24 hours from placement of the first venous access. Cortisol and adrenocorticotropic hormone were measured every 10 and 60 minutes, respectively, and corticosteroid-binding globulin was measured at the beginning and end of the 24-hour period and at the end of operation. There was an initial rise in both levels of adrenocorticotropic hormone and cortisol to supranormal values at around the end of surgery. Adrenocorticotropic hormone levels then returned toward preoperative values. Ultradian pulsatility of both adrenocorticotropic hormone and cortisol was maintained throughout the perioperative period in all individuals. The sensitivity of the adrenal gland to adrenocorticotropic hormone increased markedly at around 8 hours after surgery maintaining very high levels of cortisol in the face of "basal" levels of adrenocorticotropic hormone. This sensitivity began to return toward preoperative values at the end of the 24-hour sampling period. ANIMAL STUDIES Adult, male Sprague-Dawley rats were given either lipopolysaccharide or sterile saline via a jugular vein cannula. Hourly blood samples were subsequently collected for adrenocorticotropic hormone and corticosterone measurement. Rats were killed 6 hours after the injection, and the adrenal glands were collected for measurement of steroidogenic acute regulatory protein, steroidogenic factor 1, and dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 messenger RNAs and protein using real-time quantitative polymerase chain reaction and Western immunoblotting, respectively. Adrenal levels of the adrenocorticotropic hormone receptor (melanocortin type 2 receptor) messenger RNA and its accessory protein (melanocortin type 2 receptor accessory protein) were also measured by real-time quantitative polymerase chain reaction. In response to lipopolysaccharide, rats showed a pattern of adrenocorticotropic hormone and corticosterone that was similar to patients undergoing coronary artery bypass grafting. We were also able to demonstrate increased intra-adrenal corticosterone levels and an increase in steroidogenic acute regulatory protein, steroidogenic factor 1, and melanocortin type 2 receptor accessory protein messenger RNAs and steroidogenic acute regulatory protein, and a reduction in dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 and melanocortin type 2 receptor messenger RNAs, 6 hours after lipopolysaccharide injection. CONCLUSIONS Severe inflammatory stimuli activate the hypothalamic-pituitary-adrenal axis resulting in increased steroidogenic activity in the adrenal cortex and an elevation of cortisol levels in the blood. Following coronary artery bypass grafting, there is a massive increase in both adrenocorticotropic hormone and cortisol secretion. Despite a subsequent fall of adrenocorticotropic hormone to basal levels, cortisol remains elevated and coordinated adrenocorticotropic hormone-cortisol pulsatility is maintained. This suggested that there is an increase in adrenal sensitivity to adrenocorticotropic hormone, which we confirmed in our animal model of immune activation of the hypothalamic-pituitary-adrenal axis. Using this model, we were able to show that this increased adrenal sensitivity results from changes in the regulation of both stimulatory and inhibitory intra-adrenal signaling pathways. Increased understanding of the dynamics of normal hypothalamic-pituitary-adrenal responses to major surgery will provide us with a more rational approach to glucocorticoid therapy in critically ill patients.
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Affiliation(s)
- Ben Gibbison
- Department of Cardiac Anesthesia, Bristol Heart Institute, Bristol, UK
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
| | - Francesca Spiga
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
| | - Jamie J Walker
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
- College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, UK
| | - Georgina M Russell
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
| | - Kirsty Stevenson
- Department of Clinical Biochemistry, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Yvonne Kershaw
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
| | - Zidong Zhao
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
| | - David Henley
- Department of Endocrinology, Sir Charles Gairdner Hospital. Perth, WA. Australia
- Faculty of Medicine, Dentistry and Health Sciences. University of Western Australia, Crawley, WA, Australia
| | - Gianni D Angelini
- Department of Cardiac Surgery, Bristol Heart Institute, Bristol, UK
- National Heart and Lung Institute, Imperial College, London. UK
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
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158
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Charles MS, Drunalini Perera PN, Doycheva DM, Tang J. Granulocyte-colony stimulating factor activates JAK2/PI3K/PDE3B pathway to inhibit corticosterone synthesis in a neonatal hypoxic-ischemic brain injury rat model. Exp Neurol 2015; 272:152-9. [PMID: 25816736 DOI: 10.1016/j.expneurol.2015.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/16/2015] [Accepted: 03/19/2015] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Our previous study demonstrated that granulocyte-colony stimulating factor (G-CSF)-induced neuroprotection is accompanied by an inhibition of corticosterone production in a neonatal hypoxic-ischemic (HI) rat model. The present study investigates how G-CSF inhibits corticosterone production, using adrenal cortical cells and HI rat pups. METHODS Cholera toxin was used to induce corticosterone synthesis in a rodent Y1 adrenal cortical cell line by increasing cyclic adenosine monophosphate (cAMP). Both corticosterone and cAMP were quantitatively measured using a commercial enzyme-linked immunosorbent assay (ELISA). The downstream signaling components of the G-CSF receptor, including Janus Kinase 2 (JAK2)/Phosphatidylinositol-3-kinase (PI3K)/Protein kinase B (Akt) and Phosphodiesterase 3B (PDE3B), were detected by western blot. Sprague-Dawley rat pups at the age of 10days (P10) were subjected to unilateral carotid artery ligation followed by hypoxia for 2.5hours. Brain infarction volumes were determined using 2,3,5-triphenyltetrazolium chloride monohydrate (TTC) staining. RESULTS G-CSF at 30ng/ml inhibited corticosterone synthesis but lost its inhibitory effect at higher doses. The inhibitory effect of G-CSF was conferred by interfering with cAMP signaling via the activation of the JAK2/PI3K/PDE3B signaling pathway. The degradation of cAMP by G-CSF signaling reduced corticosterone production. This mechanism was further verified in the neonatal HI brain injury rat model, in which inhibition of PDE3B reversed the protective effects of G-CSF. CONCLUSION Our data suggest that the neuroprotective G-CSF reduces corticosterone synthesis at the adrenal level by degrading intracellular cAMP via activation of the JAK2/PI3K/PDE3B pathway.
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Affiliation(s)
- Mélissa S Charles
- Department of Microbiology and Molecular Genetics, Loma Linda University School of Medicine, Loma Linda, CA, 92354 USA; Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, 92354 USA
| | - Pradilka N Drunalini Perera
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, 92354 USA
| | - Desislava Met Doycheva
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, 92354 USA
| | - Jiping Tang
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, 92354 USA.
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159
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StAR Protein Stability in Y1 and Kin-8 Mouse Adrenocortical Cells. BIOLOGY 2015; 4:200-15. [PMID: 25749137 PMCID: PMC4381226 DOI: 10.3390/biology4010200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/13/2015] [Accepted: 02/20/2015] [Indexed: 01/30/2023]
Abstract
The steroidogenic acute regulatory protein (STAR) protein expression is required for cholesterol transport into mitochondria to initiate steroidogenesis in the adrenal and gonads. STAR is synthesized as a 37 kDa precursor protein which is targeted to the mitochondria and imported and processed to an intra-mitochondrial 30 kDa protein. Tropic hormone stimulation of the cAMP-dependent protein kinase A (PKA) signaling pathway is the major contributor to the transcriptional and post-transcriptional regulation of STAR synthesis. Many studies have focused on the mechanisms of cAMP-PKA mediated control of STAR synthesis while there are few reports on STAR degradation pathways. The objective of this study was to determine the effect of cAMP-PKA-dependent signaling on STAR protein stability. We have used the cAMP-PKA responsive Y1 mouse adrenocortical cells and the PKA-deficient Kin-8 cells to measure STAR phosphorylation and protein half-life. Western blot analysis and standard radiolabeled pulse-chase experiments were used to determine STAR phosphorylation status and protein half-life, respectively. Our data demonstrate that PKA-dependent STAR phosphorylation does not contribute to 30 kDa STAR protein stability in the mitochondria. We further show that inhibition of the 26S proteasome does not block precursor STAR phosphorylation or steroid production in Y1 cells. These data suggest STAR can maintain function and promote steroidogenesis under conditions of proteasome inhibition.
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160
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Selvaraj V, Stocco DM, Tu LN. Minireview: translocator protein (TSPO) and steroidogenesis: a reappraisal. Mol Endocrinol 2015; 29:490-501. [PMID: 25730708 DOI: 10.1210/me.2015-1033] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The 18-kDa translocator protein (TSPO), also known as the peripheral benzodiazepine receptor, is a transmembrane protein in the outer mitochondrial membrane. TSPO has long been described as being indispensable for mitochondrial cholesterol import that is essential for steroid hormone production. In contrast to this initial proposition, recent experiments reexamining TSPO function have demonstrated that it is not involved in steroidogenesis. This fundamental change has forced a reexamination of the functional interpretations made for TSPO that broadly impacts both basic and clinical research across multiple fields. In this minireview, we recapitulate the key studies from 25 years of TSPO research and concurrently examine their limitations that perhaps led towards the incorrect association of TSPO and steroid hormone production. Although this shift in understanding raises new questions regarding the molecular function of TSPO, these recent developments are poised to have a significant positive impact for research progress in steroid endocrinology.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal Science (V.S., L.N.T.), Cornell University, Ithaca, New York 14853; and Department of Cell Biology and Biochemistry (D.M.S.), Texas Tech University Health Sciences Center, Lubbock, Texas 79430
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161
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Sahakitrungruang T. Clinical and molecular review of atypical congenital adrenal hyperplasia. Ann Pediatr Endocrinol Metab 2015; 20:1-7. [PMID: 25883920 PMCID: PMC4397267 DOI: 10.6065/apem.2015.20.1.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/05/2015] [Indexed: 11/20/2022] Open
Abstract
Congenital adrenal hyperplasia (CAH) is one of the most common inherited metabolic disorders. It comprises a group of autosomal recessive disorders caused by the mutations in the genes encoding for steroidogenic enzymes that involved cortisol synthesis. More than 90% of cases are caused by a defect in the enzyme 21-hydroxylase. Four other enzyme deficiencies (cholesterol side-chain cleavage, 17α-hydroxylase [P450c17], 11β-hydroxylase [P450c11β], 3β-hydroxysteroid dehydrogenase) in the steroid biosynthesis pathway, along with one cholesterol transport protein defect (steroidogenic acute regulatory protein), and one electrontransfer protein (P450 oxidoreductase) account for the remaining cases. The clinical symptoms of the different forms of CAH result from the particular hormones that are deficient and those that are produced in excess. A characteristic feature of CAH is genital ambiguity or disordered sex development, and most variants are associated with glucocorticoid deficiency. However, in the rare forms of CAH other than 21-hydroxylase deficiency so-called "atypical CAH", the clinical and hormonal phenotypes can be more complicated, and are not well recognized. This review will focus on the atypical forms of CAH, including the genetic analyses, and phenotypic correlates.
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Affiliation(s)
- Taninee Sahakitrungruang
- Division of Pediatric Endocrinology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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162
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Wang J, Liu S, Peng L, Dong Q, Bao R, Lv Q, Tang M, Hu C, Li G, Liang S, Zhang C. Notch Signaling Pathway Regulates Progesterone Secretion in Murine Luteal Cells. Reprod Sci 2015; 22:1243-51. [PMID: 25701842 DOI: 10.1177/1933719115572480] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Notch signaling is an evolutionarily conserved pathway, which involves in various cell life activities. Other studies and our report showed that the Notch signaling plays very important role in follicle development in mammalian ovaries. In luteal cells, Notch ligand, delta-like ligand 4, is involved in normal luteal vasculature. In this study, murine luteal cells were cultured in vitro and treated with Notch signaling inhibitors, L-658,458 and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycinet-butyl ester (DAPT). We found that L-658,458 and DAPT treatment decrease basal and human chorionic gonadotropin (hCG)-stimulated progesterone secretion. On the contrary, overexpression of intracellular domain of Notch3 increased basal and hCG-stimulated progesterone secretion. Further studies demonstrated that Notch signaling regulated the expression of steroidogenic acute regulatory protein and CYP11A, 2 key enzymes for progesterone synthesis. In conclusion, Notch signaling plays important role in regulating progesterone secretion in murine luteal cells.
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Affiliation(s)
- Jing Wang
- Department of Microbiology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Shuangmei Liu
- Department of Physiology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Lichao Peng
- Department of Physiology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Qiming Dong
- Joint Programme of Nanchang University and Queen Mary University of London, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Riqiang Bao
- Joint Programme of Nanchang University and Queen Mary University of London, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Qiulan Lv
- Department of Physiology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Min Tang
- Department of Cell Biology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Chuan Hu
- Department of Cell Biology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Gang Li
- Department of Cell Biology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Shangdong Liang
- Department of Physiology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Chunping Zhang
- Department of Cell Biology, School of Medicine, Nanchang University, Nanchang, Jiangxi, People's Republic of China
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163
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Aghazadeh Y, Zirkin BR, Papadopoulos V. Pharmacological regulation of the cholesterol transport machinery in steroidogenic cells of the testis. VITAMINS AND HORMONES 2015; 98:189-227. [PMID: 25817870 DOI: 10.1016/bs.vh.2014.12.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Reduced serum testosterone (T), or hypogonadism, is estimated to affect about 5 million American men, including both aging and young men. Low serum T has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass and bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Administering exogenous T, known as T-replacement therapy (TRT), reverses many of the symptoms of low T levels. However, this treatment can result in luteinizing hormone suppression which, in turn, can lead to reduced sperm numbers and infertility, making TRT inappropriate for men who wish to father children. Additionally, TRT may result in supraphysiologic T levels, skin irritation, and T transfer to others upon contact; and there may be increased risk of prostate cancer and cardiovascular disease, particularly in aging men. Therefore, the development of alternate therapies for treating hypogonadism would be highly desirable. To do so requires greater understanding of the series of steps leading to T formation and how they are regulated, and the identification of key steps that are amenable to pharmacological modulation so as to induce T production. We review herein our current understanding of mechanisms underlying the pharmacological induction of T formation in hypogonadal testis.
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Affiliation(s)
- Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Barry R Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Biochemistry, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
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Baxter RM, Arboleda VA, Lee H, Barseghyan H, Adam MP, Fechner PY, Bargman R, Keegan C, Travers S, Schelley S, Hudgins L, Mathew RP, Stalker HJ, Zori R, Gordon OK, Ramos-Platt L, Pawlikowska-Haddal A, Eskin A, Nelson SF, Délot E, Vilain E. Exome sequencing for the diagnosis of 46,XY disorders of sex development. J Clin Endocrinol Metab 2015; 100:E333-44. [PMID: 25383892 PMCID: PMC4318895 DOI: 10.1210/jc.2014-2605] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 11/04/2014] [Indexed: 11/19/2022]
Abstract
CONTEXT Disorders of sex development (DSD) are clinical conditions where there is a discrepancy between the chromosomal sex and the phenotypic (gonadal or genital) sex of an individual. Such conditions can be stressful for patients and their families and have historically been difficult to diagnose, especially at the genetic level. In particular, for cases of 46,XY gonadal dysgenesis, once variants in SRY and NR5A1 have been ruled out, there are few other single gene tests available. OBJECTIVE We used exome sequencing followed by analysis with a list of all known human DSD-associated genes to investigate the underlying genetic etiology of 46,XY DSD patients who had not previously received a genetic diagnosis. DESIGN Samples were either submitted to the research laboratory or submitted as clinical samples to the UCLA Clinical Genomic Center. Sequencing data were filtered using a list of genes known to be involved in DSD. RESULTS We were able to identify a likely genetic diagnosis in more than a third of cases, including 22.5% with a pathogenic finding, an additional 12.5% with likely pathogenic findings, and 15% with variants of unknown clinical significance. CONCLUSIONS Early identification of the genetic cause of a DSD will in many cases streamline and direct the clinical management of the patient, with more focused endocrine and imaging studies and better-informed surgical decisions. Exome sequencing proved an efficient method toward such a goal in 46,XY DSD patients.
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Affiliation(s)
- Ruth M Baxter
- Departments of Human Genetics (R.M.B., V.A.A., H.B., A.E., S.F.N., E.D., E.V.) and Pathology and Laboratory Medicine (V.A.A., H.L., S.F.N.), David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095; Department of Pediatrics (M.P.A.), University of Washington, Seattle, Washington 98195; Department of Endocrinology (P.Y.F.), Seattle Children's Hospital, Seattle, Washington 98105; Nassau University Medical Center (R.B.), East Meadow, New York 11554; Departments of Pediatrics and Human Genetics (C.K.), Ann Arbor, Michigan 48109; The Children's Hospital Colorado (S.T.), Aurora, Colorado 80045; Division of Medical Genetics (S.S., L.H.), Stanford University, Lucile Packard Children's Hospital, Stanford, California 94305; TriStar Children's Specialists (R.P.M.), Nashville, Tennessee 37203; Division of Pediatric Genetics and Metabolism (H.J.S., R.Z.), University of Florida, Gainesville, Florida 32610; Cedars-Sinai Medical Center (O.K.G.), Los Angeles, California 90048; Children's Hospital of Los Angeles (L.R.-P.), Los Angeles, California 90027; and Departments of Pediatrics (A.P.-H., E.D., E.V.) and Urology (E.V.), David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
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165
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Park SY, Gomes C, Oh SD, Soh J. Cadmium up-regulates transcription of the steroidogenic acute regulatory protein (StAR) gene through phosphorylated CREB rather than SF-1 in K28 cells. J Toxicol Sci 2015; 40:151-61. [DOI: 10.2131/jts.40.151] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Soo-Yun Park
- Biosafety Division, National Academy of Agricultural Science, Rural Development Administration, Korea
| | - Cynthia Gomes
- University of South Carolina, Department of Biology, USA
| | - Sung-Dug Oh
- Biosafety Division, National Academy of Agricultural Science, Rural Development Administration, Korea
| | - Jaemog Soh
- Hormone Research Center and School of Biological Sciences and Technology, Chonnam National University, Korea
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166
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Goodarzi MO, Carmina E, Azziz R. DHEA, DHEAS and PCOS. J Steroid Biochem Mol Biol 2015; 145:213-25. [PMID: 25008465 DOI: 10.1016/j.jsbmb.2014.06.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/16/2014] [Accepted: 06/05/2014] [Indexed: 11/17/2022]
Abstract
Approximately 20-30% of PCOS women demonstrate excess adrenal precursor androgen (APA) production, primarily using DHEAS as a marker of APA in general and more specifically DHEA, synthesis. The role of APA excess in determining or causing PCOS is unclear, although observations in patients with inherited APA excess (e.g., patients with 21-hydroxylase deficient congenital classic or non-classic adrenal hyperplasia) demonstrate that APA excess can result in a PCOS-like phenotype. Inherited defects of the enzymes responsible for steroid biosynthesis, or defects in cortisol metabolism, account for only a very small fraction of women suffering from hyperandrogenism or APA excess. Rather, women with PCOS and APA excess appear to have a generalized exaggeration in adrenal steroidogenesis in response to ACTH stimulation, although they do not have an overt hypothalamic-pituitary-adrenal axis dysfunction. In general, extra-adrenal factors, including obesity, insulin and glucose levels, and ovarian secretions, play a limited role in the increased APA production observed in PCOS. Substantial heritabilities of APAs, particularly DHEAS, have been found in the general population and in women with PCOS; however, the handful of SNPs discovered to date account only for a small portion of the inheritance of these traits. Paradoxically, and as in men, elevated levels of DHEAS appear to be protective against cardiovascular risk in women, although the role of DHEAS in modulating this risk in women with PCOS remains unknown. In summary, the exact cause of APA excess in PCOS remains unclear, although it may reflect a generalized and inherited exaggeration in androgen biosynthesis of an inherited nature.
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Affiliation(s)
| | | | - Ricardo Azziz
- Georgia Regents University, Office of the President, 120 15th St., AA 311, Augusta, GA 30912, USA.
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167
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Abstract
OBJECTIVE The American Association of Clinical Endocrinologists Adrenal Scientific Committee has developed a series of articles to update members on the genetics of adrenal diseases. METHODS Case presentation, discussion of literature, table, and bullet point conclusions. RESULTS The congenital adrenal hyperplasia (CAH) syndromes are autosomal recessive defects in cortisol biosynthesis. The phenotype of each CAH patient depends on the defective enzyme and the severity of the defect. Clinical manifestations derive from both failure to synthesize hormones distal to the enzymatic block, as well as consequences from cortisol precursor accumulation proximal to the block, often with diversion to other biologically active steroids. The most common form of CAH is 21-hydroxylase deficiency, which occurs in the classic form in 1 in 16,000 newborns and in a milder or nonclassic form in at least 1 in 1,000 people. CONCLUSION This article reviews the various forms of CAH and pitfalls in the diagnosis and treatment of these conditions.
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168
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Corona G, Ratrelli G, Maggi M. The pharmacotherapy of male hypogonadism besides androgens. Expert Opin Pharmacother 2014; 16:369-87. [DOI: 10.1517/14656566.2015.993607] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Giovanni Corona
- 1University of Florence, Maggiore-Bellaria Hospital, Medical Department, Endocrinology Unit, Azienda-Usl Bologna, Bologna, Italy
| | - Giulia Ratrelli
- 2University of Florence, Department of Experimental, Clinical and Biomedical Sciences, Sexual Medicine and Andrology Unit, Florence, Italy; ;
| | - Mario Maggi
- 2University of Florence, Department of Experimental, Clinical and Biomedical Sciences, Sexual Medicine and Andrology Unit, Florence, Italy; ;
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169
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Abstract
Critical illness represents a major challenge for the human body, implicating that an adequate stress response is indispensable for survival. Therefore, for a long time, activation of the hypothalamic pituitary adrenal axis was assumed to be increased to respond to this stressful situation. Recent novel insights, however, provided evidence that the HPA-axis is regulated differently during critical illness. Cortisol metabolism was shown to be reduced which contributed to hypercortisolism in an energy efficient way without increasing cortisol production dramatically. Yet, the concomitant low ACTH levels, explained by negative feedback inhibition, could lead to an understimulation of the adrenal gland and affect adrenal structure and function, given the crucial role of ACTH for adrenal gland maintenance. This side-effect could negatively affect outcome predominantly in the prolonged phase of critical illness and could explain the increased incidence of adrenal failure in these patients. Altogether, novel findings represent a paradigm shift in our current understanding of HPA-axis regulation during critical illness and redirect future research perspectives with an urgent need to well-designed clinical trials to further explore HPA-axis functioning during critical illness.
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170
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Abstract
Congenital lipoid adrenal hyperplasia (lipoid CAH) is the most fatal form of CAH, as it disrupts adrenal and gonadal steroidogenesis. Most cases of lipoid CAH are caused by recessive mutations in the gene encoding steroidogenic acute regulatory protein (StAR). Affected patients typically present with signs of severe adrenal failure in early infancy and 46,XY genetic males are phenotypic females due to disrupted testicular androgen secretion. The StAR p.Q258X mutation accounts for about 70% of affected alleles in most patients of Japanese and Korean ancestry. However, it is more prevalent (92.3%) in the Korean population. Recently, some patients have been showed that they had late and mild clinical findings. These cases and studies constitute a new entity of 'nonclassic lipoid CAH'. The cholesterol side-chain cleavage enzyme, P450scc (CYP11A1), plays an essential role converting cholesterol to pregnenolone. Although progesterone production from the fetally derived placenta is necessary to maintain a pregnancy to term, some patients with P450scc mutations have recently been reported. P450scc mutations can also cause lipoid CAH and establish a recently recognized human endocrine disorder.
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Affiliation(s)
- Chan Jong Kim
- Department of Pediatrics, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
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171
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Raff H, Sharma ST, Nieman LK. Physiological basis for the etiology, diagnosis, and treatment of adrenal disorders: Cushing's syndrome, adrenal insufficiency, and congenital adrenal hyperplasia. Compr Physiol 2014; 4:739-69. [PMID: 24715566 DOI: 10.1002/cphy.c130035] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis is a classic neuroendocrine system. One of the best ways to understand the HPA axis is to appreciate its dynamics in the variety of diseases and syndromes that affect it. Excess glucocorticoid activity can be due to endogenous cortisol overproduction (spontaneous Cushing's syndrome) or exogenous glucocorticoid therapy (iatrogenic Cushing's syndrome). Endogenous Cushing's syndrome can be subdivided into ACTH-dependent and ACTH-independent, the latter of which is usually due to autonomous adrenal overproduction. The former can be due to a pituitary corticotroph tumor (usually benign) or ectopic ACTH production from tumors outside the pituitary; both of these tumor types overexpress the proopiomelanocortin gene. The converse of Cushing's syndrome is the lack of normal cortisol secretion and is usually due to adrenal destruction (primary adrenal insufficiency) or hypopituitarism (secondary adrenal insufficiency). Secondary adrenal insufficiency can also result from a rapid discontinuation of long-term, pharmacological glucocorticoid therapy because of HPA axis suppression and adrenal atrophy. Finally, mutations in the steroidogenic enzymes of the adrenal cortex can lead to congenital adrenal hyperplasia and an increase in precursor steroids, particularly androgens. When present in utero, this can lead to masculinization of a female fetus. An understanding of the dynamics of the HPA axis is necessary to master the diagnosis and differential diagnosis of pituitary-adrenal diseases. Furthermore, understanding the pathophysiology of the HPA axis gives great insight into its normal control.
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Affiliation(s)
- Hershel Raff
- Endocrine Research Laboratory, Aurora St. Luke's Medical Center, Aurora Research Institute and Departments of Medicine, Surgery, and Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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172
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Liu G, Middleton RJ, Hatty CR, Kam WW, Chan R, Pham T, Harrison‐Brown M, Dodson E, Veale K, Banati RB. The 18 kDa translocator protein, microglia and neuroinflammation. Brain Pathol 2014; 24:631-53. [PMID: 25345894 PMCID: PMC8029074 DOI: 10.1111/bpa.12196] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 08/19/2014] [Indexed: 12/17/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is expressed in the injured brain. It has become known as an imaging marker of "neuroinflammation" indicating active disease, and is best interpreted as a nondiagnostic biomarker and disease staging tool that refers to histopathology rather than disease etiology. The therapeutic potential of TSPO as a drug target is mostly based on the understanding that it is an outer mitochondrial membrane protein required for the translocation of cholesterol, which thus regulates the rate of steroid synthesis. This pivotal role together with the evolutionary conservation of TSPO has underpinned the belief that any loss or mutation of TSPO should be associated with significant physiological deficits or be outright incompatible with life. However, against prediction, full Tspo knockout mice are viable and across their lifespan do not show the phenotype expected if cholesterol transport and steroid synthesis were significantly impaired. Thus, the "translocation" function of TSPO remains to be better substantiated. Here, we discuss the literature before and after the introduction of the new nomenclature for TSPO and review some of the newer findings. In light of the controversy surrounding the function of TSPO, we emphasize the continued importance of identifying compounds with confirmed selectivity and suggest that TSPO expression is analyzed within specific disease contexts rather than merely equated with the reified concept of "neuroinflammation."
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Affiliation(s)
- Guo‐Jun Liu
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Ryan J. Middleton
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Claire R. Hatty
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Winnie Wai‐Ying Kam
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Ronald Chan
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Tien Pham
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Meredith Harrison‐Brown
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Eoin Dodson
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Kelly Veale
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Richard B. Banati
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
- National Imaging Facility and Ramaciotti Brain Imaging CentreSydneyNSWAustralia
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173
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Esparza-Perusquía M, Olvera-Sánchez S, Flores-Herrera O, Flores-Herrera H, Guevara-Flores A, Pardo JP, Espinosa-García MT, Martínez F. Mitochondrial proteases act on STARD3 to activate progesterone synthesis in human syncytiotrophoblast. Biochim Biophys Acta Gen Subj 2014; 1850:107-17. [PMID: 25459514 DOI: 10.1016/j.bbagen.2014.10.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 10/06/2014] [Accepted: 10/10/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND STARD1 transports cholesterol into mitochondria of acutely regulated steroidogenic tissue. It has been suggested that STARD3 transports cholesterol in the human placenta, which does not express STARD1. STARD1 is proteolytically activated into a 30-kDa protein. However, the role of proteases in STARD3 modification in the human placenta has not been studied. METHODS Progesterone determination and Western blot using anti-STARD3 antibodies showed that mitochondrial proteases cleave STARD3 into a 28-kDa fragment that stimulates progesterone synthesis in isolated syncytiotrophoblast mitochondria. Protease inhibitors decrease STARD3 transformation and steroidogenesis. RESULTS STARD3 remained tightly bound to isolated syncytiotrophoblast mitochondria. Simultaneous to the increase in progesterone synthesis, STARD3 was proteolytically processed into four proteins, of which a 28-kDa protein was the most abundant. This protein stimulated mitochondrial progesterone production similarly to truncated-STARD3. Maximum levels of protease activity were observed at pH7.5 and were sensitive to 1,10-phenanthroline, which inhibited steroidogenesis and STARD3 proteolytic cleavage. Addition of 22(R)-hydroxycholesterol increased progesterone synthesis, even in the presence of 1,10-phenanthroline, suggesting that proteolytic products might be involved in mitochondrial cholesterol transport. CONCLUSION Metalloproteases from human placental mitochondria are involved in steroidogenesis through the proteolytic activation of STARD3. 1,10-Phenanthroline inhibits STARD3 proteolytic cleavage. The 28-kDa protein and the amino terminal truncated-STARD3 stimulate steroidogenesis in a comparable rate, suggesting that both proteins share similar properties, probably the START domain that is involved in cholesterol binding. GENERAL SIGNIFICANCE Mitochondrial proteases are involved in syncytiotrophoblast-cell steroidogenesis regulation. Understanding STARD3 activation and its role in progesterone synthesis is crucial to getting insight into its action mechanism in healthy and diseased syncytiotrophoblast cells.
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Affiliation(s)
| | - Sofía Olvera-Sánchez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Oscar Flores-Herrera
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Héctor Flores-Herrera
- Departamento de Bioquímica y Biología Molecular, Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Mexico
| | - Alberto Guevara-Flores
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Juan Pablo Pardo
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | | | - Federico Martínez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
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174
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Tu LN, Morohaku K, Manna PR, Pelton SH, Butler WR, Stocco DM, Selvaraj V. Peripheral benzodiazepine receptor/translocator protein global knock-out mice are viable with no effects on steroid hormone biosynthesis. J Biol Chem 2014; 289:27444-54. [PMID: 24936060 PMCID: PMC4183784 DOI: 10.1074/jbc.m114.578286] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 05/30/2014] [Indexed: 01/19/2023] Open
Abstract
Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is a mitochondrial outer membrane protein implicated as essential for cholesterol import to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Previous research on TSPO was based entirely on in vitro experiments, and its critical role was reinforced by an early report that claimed TSPO knock-out mice were embryonic lethal. In a previous publication, we examined Leydig cell-specific TSPO conditional knock-out mice that suggested TSPO was not required for testosterone production in vivo. This raised controversy and several questions regarding TSPO function. To examine the definitive role of TSPO in steroidogenesis and embryo development, we generated global TSPO null (Tspo(-/-)) mice. Contrary to the early report, Tspo(-/-) mice survived with no apparent phenotypic abnormalities and were fertile. Examination of adrenal and gonadal steroidogenesis showed no defects in Tspo(-/-) mice. Adrenal transcriptome comparison of gene expression profiles showed that genes involved in steroid hormone biosynthesis (Star, Cyp11a1, and Hsd3b1) were unchanged in Tspo(-/-) mice. Adrenocortical ultrastructure illustrated no morphological alterations in Tspo(-/-) mice. In an attempt to correlate our in vivo findings to previously used in vitro models, we also determined that siRNA knockdown or the absence of TSPO in different mouse and human steroidogenic cell lines had no effect on steroidogenesis. These findings directly refute the dogma that TSPO is indispensable for steroid hormone biosynthesis and viability. By amending the current model, this study advances our understanding of steroidogenesis with broad implications in biology and medicine.
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Affiliation(s)
- Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Pulak R Manna
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Susanne H Pelton
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - W Ronald Butler
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Douglas M Stocco
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
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175
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Turcu A, Smith JM, Auchus R, Rainey WE. Adrenal androgens and androgen precursors-definition, synthesis, regulation and physiologic actions. Compr Physiol 2014; 4:1369-81. [PMID: 25428847 PMCID: PMC4437668 DOI: 10.1002/cphy.c140006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The human adrenal produces more 19 carbon (C19) steroids, by mass, than either glucocorticoids or mineralocorticoids. However, the mechanisms regulating adrenal C19 steroid biosynthesis continue to represent one of the most intriguing mysteries of endocrine physiology. This review will discuss the C19 steroids synthesized by the human adrenal and the features within the adrenal that allow production of these steroids. Finally, we consider the effects of these steroids in normal physiology and disorders of adrenal C19 steroid excess.
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Affiliation(s)
- Adina Turcu
- Department of Internal Medicine, Division of Metabolism Endocrinology and Diabetes, University of Michigan, Ann Arbor, Michigan; Department of Pediatrics, Division of Pediatric Endocrinology, University of Texas Southwestern Medical Center, Texas; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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Duan FH, Chen SL, Chen X, Niu J, Li P, Liu YD, Xu LJ. Follicular fluid Aβ40 concentrations may be associated with ongoing pregnancy following in vitro fertilization. J Assist Reprod Genet 2014; 31:1611-20. [PMID: 25241131 DOI: 10.1007/s10815-014-0345-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/09/2014] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To determine whether Aβ40 levels in the follicular fluid (FF) of infertile women undergoing IVF demonstrate a relationship with IVF cycle parameters and outcome. METHODS FF Aβ40 levels were compared between patients achieving ongoing pregnancy and those with unsuccessful cycles. Clinical data such as ongoing pregnancy rate, implantation rate, number of oocytes retrieved, number of 8 cells embryos with ≤5 % fragmants, ratio of 8 cells embryos with ≤5 % fragmants to total embryos per patient and cleavage rate were compared among three percentile groups of Aβ40. CCK-8 method was used to measure the effect of Aβ40 on rat granulosa cells proliferation in vitro. RT-PCR was used to detect the mRNA expression levels of steroidogenesis related genes. RESULTS Patients achieving ongoing pregnancy (n = 26; 50.98%) demonstrated significantly higher FF Aβ40 levels compared to those with unsuccessful cycles (n = 25; 49.02%; P = 0.024). No significant differences were observed in APP (amyloid precursor protein) and its other proteolysis products including sAPPα, sAPPβand Aβ 42 between the two groups. Statistically significant differences between the three percentile groups of Aβ 40 were observed only in the implantation rates and ongoing pregnancy rates. There were no statistically significant differences between the three percentile groups in the age, No. oocytes retrieved, No. 2 pronucleus, No. embryos transferred, No. 8 cells embryos with ≤5% fragmants and cleavage rate. Significantly negative correlation exists between APP and AFC (antral follicle count) (R =-0.360, P = 0.005) and oocytes retrieved (R =-0.378, P = 0.004). There were also significantly positive correlations between Aβ40 and Aβ42 (R = 0.407, P = 0.000), between AFC and oocytes retrieved (R = 0.476, P = 0.000). Rat granulosa cells treated with Aβ40 of different concentrations have improved their proliferative ability. Cells treated with 200 pg/ml Aβ40 have the strongest ability of proliferation. 200 pg/ml Aβ40 enhanced the expression of key molecules during steroidogenesis such as IGF-1,IGF-1receptor (IGF-1R),FSH receptor (FSHR),P450 aromatase (P450arom),steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage cytochromes P450(P450scc). CONCLUSIONS Aβ40 levels in follicle fluid may be associated with ongoing pregnancy and the moderate expression level of Aβ40 is important for oocytes and embryos development.
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Affiliation(s)
- Fu-Hua Duan
- Center for Reproductive Medicine, Department of Gynecology and Obstetrics, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, People's Republic of China
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A cell-autonomous molecular cascade initiated by AMP-activated protein kinase represses steroidogenesis. Mol Cell Biol 2014; 34:4257-71. [PMID: 25225331 DOI: 10.1128/mcb.00734-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Steroid hormones regulate essential physiological processes, and inadequate levels are associated with various pathological conditions. In testosterone-producing Leydig cells, steroidogenesis is strongly stimulated by luteinizing hormone (LH) via its receptor leading to increased cyclic AMP (cAMP) production and expression of the steroidogenic acute regulatory (STAR) protein, which is essential for the initiation of steroidogenesis. Steroidogenesis then passively decreases with the degradation of cAMP into AMP by phosphodiesterases. In this study, we show that AMP-activated protein kinase (AMPK) is activated following cAMP-to-AMP breakdown in MA-10 and MLTC-1 Leydig cells. Activated AMPK then actively inhibits cAMP-induced steroidogenesis by repressing the expression of key regulators of steroidogenesis, including Star and Nr4a1. Similar results were obtained in Y-1 adrenal cells and in the constitutively steroidogenic R2C cells. We have also determined that maximum AMPK activation following stimulation of steroidogenesis in MA-10 Leydig cells occurs when steroid hormone production has reached a plateau. Our data identify AMPK as a molecular rheostat that actively represses steroid hormone biosynthesis to preserve cellular energy homeostasis and prevent excess steroid production.
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178
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Midzak A, Papadopoulos V. Binding domain-driven intracellular trafficking of sterols for synthesis of steroid hormones, bile acids and oxysterols. Traffic 2014; 15:895-914. [PMID: 24890942 DOI: 10.1111/tra.12177] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 12/16/2022]
Abstract
Steroid hormones, bioactive oxysterols and bile acids are all derived from the biological metabolism of lipid cholesterol. The enzymatic pathways generating these compounds have been an area of intense research for almost a century, as cholesterol and its metabolites have substantial impacts on human health. Owing to its high degree of hydrophobicity and the chemical properties that it confers to biological membranes, the distribution of cholesterol in cells is tightly controlled, with subcellular organelles exhibiting highly divergent levels of cholesterol. The manners in which cells maintain such sterol distributions are of great interest in the study of steroid and bile acid synthesis, as limiting cholesterol substrate to the enzymatic pathways is the principal mechanism by which production of steroids and bile acids is regulated. The mechanisms by which cholesterol moves within cells, however, remain poorly understood. In this review, we examine the subcellular machinery involved in cholesterol metabolism to steroid hormones and bile acid, relating it to both lipid- and protein-based mechanisms facilitating intracellular and intraorganellar cholesterol movement and delivery to these pathways. In particular, we examine evidence for the involvement of specific protein domains involved in cholesterol binding, which impact cholesterol movement and metabolism in steroidogenesis and bile acid synthesis. A better understanding of the physical mechanisms by which these protein- and lipid-based systems function is of fundamental importance to understanding physiological homeostasis and its perturbation.
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Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
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Yu X, Wu L, Xie L, Yang S, Charkraborty T, Shi H, Wang D, Zhou L. Characterization of two paralogous StAR genes in a teleost, Nile tilapia (Oreochromis niloticus). Mol Cell Endocrinol 2014; 392:152-62. [PMID: 24859646 DOI: 10.1016/j.mce.2014.05.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 04/18/2014] [Accepted: 05/13/2014] [Indexed: 02/01/2023]
Abstract
Steroidogenic acute regulatory protein (StAR) transports cholesterol, the substrate for steroid synthesis, to the inner membranes of mitochondria. It is well known that estrogen is essential for female sex determination/differentiation in fish. However, no reports showed that the conventional StAR, which was supposed to be essential for estrogen production, was expressed in female gonads during the critical timing of sex determination/differentiation. In this study, two different StAR isoforms, named as StAR1 and StAR2, were characterized from the gonads of Nile tilapia (Oreochromis niloticus). Phylogenetic and synteny analysis revealed that two StAR genes existed in teleosts, Xenopus and chicken indicating that the duplication event occurred before the divergence of teleosts and tetrapods. Real-time PCR revealed that StAR1 was dominantly expressed in the testis, head kidney and kidney; while StAR2 was expressed exclusively in the gonads. In situ hybridization and immunohistochemistry demonstrated that StAR1 was expressed in the interrenal cells of the head kidney and Leydig cells of the testis; while StAR2 was expressed in the Leydig cells of the testis and the interstitial cells of the ovary. Ontogenic analysis demonstrated that StAR2 was expressed abundantly from 5 days after hatching (dah) in the somatic cells in XX gonads, whereas in XY gonads, both StARs could be detected from 30 dah until adulthood. Intraperitoneal injection of human chorionic gonadotropin experiments showed that expression of StAR1 and 2 was significantly elevated at 8h and persisted until 24h after injection in the testis. Taken together, our data suggested that StAR1 is likely to be required for cortisol production in the head kidney, and StAR2 is probably involved in estrogen production during early sex differentiation in XX gonads. In contrast, both StARs might be required for androgen production in testes. For the first time, our data demonstrated that two fish StARs might be involved in steroidogenesis in a tissue and developmental stage dependent manner.
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Affiliation(s)
- Xiangguo Yu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Limin Wu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Lang Xie
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Shijie Yang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Tapas Charkraborty
- South Ehime Fisheries Research Institute, Ehime University, Matsuyama 798-4206, Japan
| | - Hongjuan Shi
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Deshou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China
| | - Linyan Zhou
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Science, Southwest University, Chongqing 400715, PR China.
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180
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Tu LN, Morohaku K, Manna PR, Pelton SH, Butler WR, Stocco DM, Selvaraj V. Peripheral benzodiazepine receptor/translocator protein global knock-out mice are viable with no effects on steroid hormone biosynthesis. J Biol Chem 2014. [PMID: 24936060 DOI: 10.10784/jbc.m114.578286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is a mitochondrial outer membrane protein implicated as essential for cholesterol import to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Previous research on TSPO was based entirely on in vitro experiments, and its critical role was reinforced by an early report that claimed TSPO knock-out mice were embryonic lethal. In a previous publication, we examined Leydig cell-specific TSPO conditional knock-out mice that suggested TSPO was not required for testosterone production in vivo. This raised controversy and several questions regarding TSPO function. To examine the definitive role of TSPO in steroidogenesis and embryo development, we generated global TSPO null (Tspo(-/-)) mice. Contrary to the early report, Tspo(-/-) mice survived with no apparent phenotypic abnormalities and were fertile. Examination of adrenal and gonadal steroidogenesis showed no defects in Tspo(-/-) mice. Adrenal transcriptome comparison of gene expression profiles showed that genes involved in steroid hormone biosynthesis (Star, Cyp11a1, and Hsd3b1) were unchanged in Tspo(-/-) mice. Adrenocortical ultrastructure illustrated no morphological alterations in Tspo(-/-) mice. In an attempt to correlate our in vivo findings to previously used in vitro models, we also determined that siRNA knockdown or the absence of TSPO in different mouse and human steroidogenic cell lines had no effect on steroidogenesis. These findings directly refute the dogma that TSPO is indispensable for steroid hormone biosynthesis and viability. By amending the current model, this study advances our understanding of steroidogenesis with broad implications in biology and medicine.
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Affiliation(s)
- Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Pulak R Manna
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Susanne H Pelton
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - W Ronald Butler
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Douglas M Stocco
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
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Chi ML, Wen HS, Ni M, He F, Li JF, Qian K, Zhang P, Chai SH, Ding YX, Yin XH. Molecular identification of genes involved in testicular steroid synthesis and characterization of the responses to hormones stimulation in testis of Japanese sea bass (Lateolabrax japonicas). Steroids 2014; 84:92-102. [PMID: 24704264 DOI: 10.1016/j.steroids.2014.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 03/21/2014] [Indexed: 11/20/2022]
Abstract
Testicular steroids are critical hormones for the regulation of spermatogenesis in male teleosts and their productions have been reported to be regulated by gonadotropins and gonadotropin-releasing hormone. In the Japanese sea bass (Lateolabrax japonicas), the reproductive endocrine, particularly regarding the production and regulation of testicular steroids, are not well understood. For this reason, we first cloned and characterized the response of several key genes regulating the production of testicular steroids and, second, we analyzed the changes of mRNA profiles of these genes during testicular development cycle and in the administration of hCG and GnRHa with corresponding testosterone level in serum, GSI and histological analyses. We succeeded in cloning the full-length cDNAs for the fushi tarazu factor-1 (FTZ-F1) homologues (FTZ-F1a and FTZ-F1b), steroidogenic acute regulatory protein (StAR) and anti-Müllerian hormone (AMH) in Japanese sea bass. Multiple sequence alignment and phylogenetic analysis of these proteins clearly showed that these genes in Japanese sea bass were homologous to those of other piscine species. During the testicular development cycle and hCG/GnRHa administration, quantification of jsbStAR transcripts revealed a trend similar to their serum testosterone levels, while a reciprocal relationship was founded between the serum concentrations of testosterone and jsbAMH and the links between gonadal expression of jsbStAR, jsbAMH and jsbFTZ-F1 were also observed. Our results have identified for the first time several key genes involved in the regulation of steroid production and spermatogenesis in the Japanese sea bass testis and these genes are all detected under gonadotropic hormone and gonadotropin-releasing hormone control.
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Affiliation(s)
- Mei L Chi
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Hai S Wen
- Fisheries College, Ocean University of China, Qingdao 266003, China.
| | - Meng Ni
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Feng He
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Ji F Li
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Kun Qian
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Pei Zhang
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Sen H Chai
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Yu X Ding
- Fisheries College, Ocean University of China, Qingdao 266003, China
| | - Xiang H Yin
- Fisheries College, Ocean University of China, Qingdao 266003, China
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183
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Sasaki G, Zubair M, Ishii T, Mitsui T, Hasegawa T, Auchus RJ. The contribution of serine 194 phosphorylation to steroidogenic acute regulatory protein function. Mol Endocrinol 2014; 28:1088-96. [PMID: 24850413 DOI: 10.1210/me.2014-1028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The steroidogenic acute regulatory protein (StAR) facilitates the delivery of cholesterol to the inner mitochondrial membrane, where the cholesterol side-chain cleavage enzyme catalyzes the initial step of steroid hormone biosynthesis. StAR was initially identified in adrenocortical cells as a phosphoprotein, the expression and phosphorylation of which were stimulated by corticotropin. A number of in vitro studies have implicated cAMP-dependent phosphorylation at serine 194 (S194, S195 in human StAR) as an important residue for StAR activity. To explore the importance of S194 phosphorylation in StAR function in vivo, we developed a transgenic model using a bacterial artificial chromosome expressing either wild-type (WT) StAR or StAR mutation S194A to rescue StAR knockout (KO) mice. Despite StAR protein expression comparable to or higher than amounts seen with control animals or rescue with WT StAR, S194A StAR did not rescue the neonatal lethality and only partially rescued the sex reversal in male mice observed uniformly in StAR KO mice. Like the StAR KO mice, the adrenal cortex and testicular Leydig cells contained abundant lipid deposits when stained with oil red O. Adrenal StAR from S194A rescue animals lacks an acidic species, which appears upon corticotropin stimulation in animals rescued with WT StAR, consistent with defective StAR phosphorylation. These findings demonstrate that S194 is an essential residue for normal StAR function in the adrenal cortex and testes of mice.
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Affiliation(s)
- Goro Sasaki
- Department of Pediatrics (G.S.), Tokyo Dental College Ichikawa General Hospital, Ichikawa, Chiba, 272-8513, Japan; Department of Internal Medicine (G.S., M.Z., R.J.A.), University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Pediatrics (T.I., T.M., T.H.), Keio University School of Medicine, Tokyo, 160-8582, Japan; PAPRSB Institute of Health Science (M.Z.), University of Brunei Darussalam, Brunei; and Department of Internal Medicine (R.J.A.), University of Michigan, Ann Arbor, Michigan 48109
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Yüksel B, Kulle AE, Gürbüz F, Welzel M, Kotan D, Mengen E, Holterhus PM, Topaloğlu AK, Grötzinger J, Riepe FG. The novel mutation p.Trp147Arg of the steroidogenic acute regulatory protein causes classic lipoid congenital adrenal hyperplasia with adrenal insufficiency and 46,XY disorder of sex development. Horm Res Paediatr 2014; 80:163-9. [PMID: 23920000 DOI: 10.1159/000354086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/25/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The steroidogenic acute regulatory protein (StAR) is essential for steroidogenesis by mediating cholesterol transfer into mitochondria. Inactivating StAR mutations cause lipoid congenital adrenal hyperplasia. OBJECTIVE AND METHODS To identify causative mutations in a patient presenting with adrenal failure during early infancy. The objective was to study the functional and structural consequences of the novel StAR mutation p.Trp147Arg in a Turkish patient detected in compound heterozygosity with the p.Glu169Lys mutation. RESULTS Transient in vitro expression of the mutant proteins together with P450 side-chain cleavage enzyme, adrenodoxin, and adrenodoxin reductase yielded severely diminished cholesterol conversion of the p.Trp147Arg mutant. The previously described p.Glu169Lys mutant led to significantly lower cholesterol conversion than wild-type StAR protein. As derived from three-dimensional protein modeling, the residue W147 is stabilizing the C-terminal helix in a closed conformation hereby acting as gatekeeper of the ligand cavity of StAR. CONCLUSIONS The novel mutation p.Trp147Arg causes primary adrenal insufficiency and complete sex reversal in the 46,XY patient. Clinical disease, in vitro studies and three-dimensional protein modeling of the mutation p.Trp147Arg underscore the relevance of this highly conserved residue for StAR protein function.
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Affiliation(s)
- Bilgin Yüksel
- Division of Pediatric Endocrinology and Metabolism, Department of Pediatrics, Cukurova University, Balcali/Adana, Turkey
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185
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Cao Y, He M, Gao Z, Peng Y, Li Y, Li L, Zhou W, Li X, Zhong X, Lei Y, Su T, Wang H, Jiang Y, Yang L, Wei W, Yang X, Jiang X, Liu L, He J, Ye J, Wei Q, Li Y, Wang W, Wang J, Ning G. Activating hotspot L205R mutation in PRKACA and adrenal Cushing's syndrome. Science 2014; 344:913-7. [PMID: 24700472 DOI: 10.1126/science.1249480] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Adrenal Cushing's syndrome is caused by excess production of glucocorticoid from adrenocortical tumors and hyperplasias, which leads to metabolic disorders. We performed whole-exome sequencing of 49 blood-tumor pairs and RNA sequencing of 44 tumors from cortisol-producing adrenocortical adenomas (ACAs), adrenocorticotropic hormone-independent macronodular adrenocortical hyperplasias (AIMAHs), and adrenocortical oncocytomas (ADOs). We identified a hotspot in the PRKACA gene with a L205R mutation in 69.2% (27 out of 39) of ACAs and validated in 65.5% of a total of 87 ACAs. Our data revealed that the activating L205R mutation, which locates in the P+1 loop of the protein kinase A (PKA) catalytic subunit, promoted PKA substrate phosphorylation and target gene expression. Moreover, we discovered the recurrently mutated gene DOT1L in AIMAHs and CLASP2 in ADOs. Collectively, these data highlight potentially functional mutated genes in adrenal Cushing's syndrome.
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Affiliation(s)
- Yanan Cao
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Minghui He
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Zhibo Gao
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Ying Peng
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Yanli Li
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Lin Li
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Weiwei Zhou
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | | | - Xu Zhong
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Yiming Lei
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Tingwei Su
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Hang Wang
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Yiran Jiang
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Lin Yang
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Wei Wei
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Xu Yang
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Xiuli Jiang
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Li Liu
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Juan He
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Junna Ye
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Qing Wei
- Department of Pathology, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Yingrui Li
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China
| | - Weiqing Wang
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.
| | - Jun Wang
- BGI-Shanghai, BGI-Shenzhen, Shenzhen, China. Department of Biology, University of Copenhagen, Copenhagen, Denmark. King Abdulaziz University, Jeddah, Saudi Arabia. Macau University of Science and Technology, Macau, China. Department of Medicine, University of Hong Kong, Hong Kong.
| | - Guang Ning
- Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China. Laboratory of Endocrinology and Metabolism, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), and Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
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Chen M, Wang X, Wang Y, Zhang L, Xu B, Lv L, Cui X, Li W, Gao F. Wt1 Is Involved in Leydig Cell Steroid Hormone Biosynthesis by Regulating Paracrine Factor Expression in Mice1. Biol Reprod 2014; 90:71. [DOI: 10.1095/biolreprod.113.114702] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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187
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Kiessling S, Sollars PJ, Pickard GE. Light stimulates the mouse adrenal through a retinohypothalamic pathway independent of an effect on the clock in the suprachiasmatic nucleus. PLoS One 2014; 9:e92959. [PMID: 24658072 PMCID: PMC3962469 DOI: 10.1371/journal.pone.0092959] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 02/27/2014] [Indexed: 01/13/2023] Open
Abstract
The brain's master circadian pacemaker resides within the hypothalamic suprachiasmatic nucleus (SCN). SCN clock neurons are entrained to the day/night cycle via the retinohypothalamic tract and the SCN provides temporal information to the central nervous system and to peripheral organs that function as secondary oscillators. The SCN clock-cell network is thought to be the hypothalamic link between the retina and descending autonomic circuits to peripheral organs such as the adrenal gland, thereby entraining those organs to the day/night cycle. However, there are at least three different routes or mechanisms by which retinal signals transmitted to the hypothalamus may be conveyed to peripheral organs: 1) via retinal input to SCN clock neurons; 2) via retinal input to non-clock neurons in the SCN; or 3) via retinal input to hypothalamic regions neighboring the SCN. It is very well documented that light-induced responses of the SCN clock (i.e., clock gene expression, neural activity, and behavioral phase shifts) occur primarily during the subjective night. Thus to determine the role of the SCN clock in transmitting photic signals to descending autonomic circuits, we compared the phase dependency of light-evoked responses in the SCN and a peripheral oscillator, the adrenal gland. We observed light-evoked clock gene expression in the mouse adrenal throughout the subjective day and subjective night. Light also induced adrenal corticosterone secretion during both the subjective day and subjective night. The irradiance threshold for light-evoked adrenal responses was greater during the subjective day compared to the subjective night. These results suggest that retinohypothalamic signals may be relayed to the adrenal clock during the subjective day by a retinal pathway or cellular mechanism that is independent of an effect of light on the SCN neural clock network and thus may be important for the temporal integration of physiology and metabolism.
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Affiliation(s)
- Silke Kiessling
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Patricia J. Sollars
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Gary E. Pickard
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Kokilavani P, Suriyakalaa U, Elumalai P, Abirami B, Ramachandran R, Sankarganesh A, Achiraman S. Antioxidant mediated ameliorative steroidogenesis by Commelina benghalensis L. and Cissus quadrangularis L. against quinalphos induced male reproductive toxicity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2014; 109:18-33. [PMID: 24581381 DOI: 10.1016/j.pestbp.2014.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/14/2014] [Indexed: 06/03/2023]
Abstract
Quinalphos (QP) is speculated to cause endocrine disruption through the generation of reactive oxygen species (ROS) by oxidative stress (OS). Exposure of QP decreased testosterone level considerably which resulted in reduced viable sperms in mice. The QP induced toxicity is initiated by the formation of free radicals as it is evidenced from the increased Lipid peroxidation (LPO) and diminution of antioxidant enzymes in testicular tissue. Increased serum cholesterol and reduced testicular cholesterol indicated the inhibition of cholesterol transport and biosynthesis in testicular tissues. Lack of cholesterol in testicular tissue impaired the steroidogenesis by down-regulating the expression of StAR protein, Cytochrome P450, 3β-HSD and 17β-HSD leading to reduced testosterone level. Treatment of Commelina benganlensis (CBE) and Cissus quadrangularis (CQE) significantly recovered the alterations in antioxidant profiles as well as increased LPO, thereby recovering the decreased mRNA expression levels of intermediate enzymes. However, CQE effectively protected the OS and prevented the inhibition of steroidogenesis thereby preventing male infertility.
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Affiliation(s)
- Palanivel Kokilavani
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
| | - Udhayaraj Suriyakalaa
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
| | - Perumal Elumalai
- Department of Endocrinology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai 600 113, India
| | - Bethunaicken Abirami
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
| | - Rajamanickam Ramachandran
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
| | - Arunachalam Sankarganesh
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India; Department of Bio Sciences and Technology, VIT University, Vellore 632 014, India
| | - Shanmugam Achiraman
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India.
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Camats N, Pandey AV, Fernández-Cancio M, Fernández JM, Ortega AM, Udhane S, Andaluz P, Audí L, Flück CE. STAR splicing mutations cause the severe phenotype of lipoid congenital adrenal hyperplasia: insights from a novel splice mutation and review of reported cases. Clin Endocrinol (Oxf) 2014; 80:191-9. [PMID: 23859637 DOI: 10.1111/cen.12293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 05/29/2013] [Accepted: 07/11/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The steroidogenic acute regulatory protein (StAR) transports cholesterol to the mitochondria for steroidogenesis. Loss of StAR function causes lipoid congenital adrenal hyperplasia (LCAH) which is characterized by impaired synthesis of adrenal and gonadal steroids causing adrenal insufficiency, 46,XY disorder of sex development (DSD) and failure of pubertal development. Partial loss of StAR activity may cause adrenal insufficiency only. PATIENT A newborn girl was admitted for mild dehydration, hyponatremia, hyperkalemia and hypoglycaemia and had normal external female genitalia without hyperpigmentation. Plasma cortisol, 17OH-progesterone, DHEA-S, androstendione and aldosterone were low, while ACTH and plasma renin activity were elevated, consistent with the diagnosis of primary adrenal insufficiency. Imaging showed normal adrenals, and cytogenetics revealed a 46,XX karyotype. She was treated with fluids, hydrocortisone and fludrocortisone. DESIGN, METHODS AND RESULTS Genetic studies revealed a novel homozygous STAR mutation in the 3' acceptor splice site of intron 4, c.466-1G>A (IVS4-1G>A). To test whether this mutation would affect splicing, we performed a minigene experiment with a plasmid construct containing wild-type or mutant StAR gDNA of exons-introns 4-6 in COS-1 cells. The splicing was assessed on total RNA using RT-PCR for STAR cDNAs. The mutant STAR minigene skipped exon 5 completely and changed the reading frame. Thus, it is predicted to produce an aberrant and shorter protein (p.V156GfsX19). Computational analysis revealed that this mutant protein lacks wild-type exons 5-7 which are essential for StAR-cholesterol interaction. CONCLUSIONS STAR c.466-1A skips exon 5 and causes a dramatic change in the C-terminal sequence of the protein, which is essential for StAR-cholesterol interaction. This splicing mutation is a loss-of-function mutation explaining the severe phenotype of our patient. Thus far, all reported splicing mutations of STAR cause a severe impairment of protein function and phenotype.
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Affiliation(s)
- Núria Camats
- Pediatric Endocrinology, Department of Pediatrics and Department of Clinical Research, University Children's Hospital Bern, Bern, Switzerland
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190
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Morohaku K, Pelton SH, Daugherty DJ, Butler WR, Deng W, Selvaraj V. Translocator protein/peripheral benzodiazepine receptor is not required for steroid hormone biosynthesis. Endocrinology 2014; 155:89-97. [PMID: 24174323 PMCID: PMC3868810 DOI: 10.1210/en.2013-1556] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molecular events that regulate cellular biosynthesis of steroid hormones have been a topic of intense research for more than half a century. It has been established that transport of cholesterol into the mitochondria forms the rate-limiting step in steroid hormone production. In current models, both the steroidogenic acute regulatory protein (StAR) and the translocator protein (TSPO) have been implicated to have a concerted and indispensable effort in this cholesterol transport. Deletion of StAR in mice resulted in a critical failure of steroid hormone production, but deletion of TSPO in mice was found to be embryonic lethal. As a result, the role of TSPO in cholesterol transport has been established only using pharmacologic and genetic tools in vitro. To allow us to explore in more detail the function of TSPO in cell type-specific experimental manipulations in vivo, we generated mice carrying TSPO floxed alleles (TSPOfl/fl). In this study we made conditional knockout mice (TSPOcΔ/Δ) with TSPO deletion in testicular Leydig cells by crossing with an anti-Mullerian hormone receptor type II cre/+ mouse line. Genetic ablation of TSPO in steroidogenic Leydig cells in mice did not affect testosterone production, gametogenesis, and reproduction. Expression of StAR, cytochrome P450 side chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase type I, and TSPO2 in TSPOcΔ/Δ testis was unaffected. These results challenge the prevailing dogma that claims an essential role for TSPO in steroid hormone biosynthesis and force reexamination of functional interpretations made for this protein. This is the first study examining conditional TSPO gene deletion in mice. The results show that TSPO function is not essential for steroid hormone biosynthesis.
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Affiliation(s)
- Kanako Morohaku
- Department of Animal Science, College of Agriculture and Life Sciences (K.M., S.H.P., W.R.B., V.S.), Cornell University, Ithaca, New York 14853; and Department of Biochemistry and Molecular Medicine, School of Medicine (D.J.D., W.D.), University of California at Davis, Sacramento, California 95618
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191
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Alpy F, Tomasetto C. START ships lipids across interorganelle space. Biochimie 2014; 96:85-95. [DOI: 10.1016/j.biochi.2013.09.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 09/17/2013] [Indexed: 11/30/2022]
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192
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Identification of early transcriptome-based biomarkers related to lipid metabolism in peripheral blood mononuclear cells of rats nutritionally programmed for improved metabolic health. GENES AND NUTRITION 2013; 9:366. [PMID: 24343050 DOI: 10.1007/s12263-013-0366-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/06/2013] [Indexed: 10/25/2022]
Abstract
Moderate maternal calorie restriction during lactation protects rat offspring against obesity development in adulthood, due to an improved ability to handle and store excess dietary fuel. We used this model to identify early transcriptome-based biomarkers of metabolic health using peripheral blood mononuclear cells (PBMCs), an easily accessible surrogate tissue, by focusing on molecular markers of lipid handling. Male and female offspring of control and 20 % calorie-restricted lactating dams (CR) were studied. At weaning, a set of pups was killed, and PBMCs were isolated for whole-genome microarray analysis. The remaining pups were killed at 6 months of age. CR gave lower body weight, food intake and fat accumulation, and improved levels of insulin and leptin throughout life, particularly in females. Microarray analysis of weaned rat PBMCs identified 278 genes significantly differentially expressed between control and CR. Among lipid metabolism-related genes, expression of Cpt1a, Lipe and Star was increased and Fasn, Lrp1 and Rxrb decreased in CR versus control, with changes fully confirmed by qPCR. Among them, Cpt1a, Fasn and Star emerged as particularly interesting. Transcript levels of Cpt1a in PBMCs correlated with their levels in WAT and liver at both ages examined; Fasn expression levels in PBMCs at an early age correlated with their expression levels in WAT; and early changes in Star expression levels in PBMCs correlated with their expression levels in liver and were sustained in adulthood. These findings reveal the possibility of using transcript levels of lipid metabolism-related genes in PBMCs as early biomarkers of metabolic health status.
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193
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Reid PM, Divers SL, Zadmajid V, Alqaisi KM, Lokman PM. Steroidogenic acute regulatory protein transcript abundance in the eel, Anguilla australis: changes during the induced reproductive cycle and effects of follicle-stimulating hormone during previtellogenesis. J Steroid Biochem Mol Biol 2013; 138:464-70. [PMID: 23403152 DOI: 10.1016/j.jsbmb.2013.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 01/30/2013] [Accepted: 02/03/2013] [Indexed: 11/21/2022]
Abstract
Steroidogenic acute regulatory protein (StAR) mRNA levels in the eel ovary were assayed by quantitative PCR and related to plasma steroid levels throughout oogenesis in order to shed light on the previously considered 'aberrant' prematurational increase in plasma levels of estradiol-17β (E2). Total ovarian StAR transcript abundance mirrored circulating levels of E2, but not of 11-ketotestosterone (11KT). The study was complemented by evaluation of in vitro effects of follicle-stimulating hormone (FSH) on ovarian StAR transcript abundance and on short-term ('acute') radiolabelled pregnenolone-supported steroid metabolism by ovarian fragments to understand how the production of steroids during previtellogenic oocyte growth is regulated. We observed a significant effect of FSH on StAR mRNA levels within 24h of incubation, but these were no longer evident by 4 days of culture. Unexpectedly, FSH had no effect on substrate-supported steroidogenesis, as comparable yields of steroid products were detected using semi-quantitative HPLC and scintillation counting. We conclude that the eel ovarian follicle can respond to FSH from a very early stage of development (early oil droplet stage) by increasing StAR mRNA levels, but that there is no evidence for acute effects of FSH on bioactive steroid production downstream of cytochrome P450 side-chain cleavage. Furthermore, the prematurational increase in StAR mRNA in vivo is in keeping with general teleost models and is likely to be a 'normal' response to reaching advanced stages of development.
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Affiliation(s)
- Peter M Reid
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin 9016, New Zealand
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194
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Miller WL. Steroid hormone synthesis in mitochondria. Mol Cell Endocrinol 2013; 379:62-73. [PMID: 23628605 DOI: 10.1016/j.mce.2013.04.014] [Citation(s) in RCA: 280] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 11/17/2022]
Abstract
Mitochondria are essential sites for steroid hormone biosynthesis. Mitochondria in the steroidogenic cells of the adrenal, gonad, placenta and brain contain the cholesterol side-chain cleavage enzyme, P450scc, and its two electron-transfer partners, ferredoxin reductase and ferredoxin. This enzyme system converts cholesterol to pregnenolone and determines net steroidogenic capacity, so that it serves as the chronic regulator of steroidogenesis. Several other steroidogenic enzymes, including 3β-hydroxysteroid dehydrogenase, 11β-hydroxylase and aldosterone synthase also reside in mitochondria. Similarly, the mitochondria of renal tubular cells contain two key enzymes participating in the activation and degradation of vitamin D. The access of cholesterol to the mitochondria is regulated by the steroidogenic acute regulatory protein, StAR, serving as the acute regulator of steroidogenesis. StAR action requires a complex multi-component molecular machine on the outer mitochondrial membrane (OMM). Components of this machine include the 18 kDa translocator protein (TSPO), the voltage-dependent anion chanel (VDAC-1), TSPO-associated protein 7 (PAP7, ACBD3), and protein kinase A regulatory subunit 1α (PKAR1A). The precise fashion in which these proteins interact and move cholesterol from the OMM to P450scc, and the means by which cholesterol is loaded into the OMM, remain unclear. Human deficiency diseases have been described for StAR and for all the mitochondrial steroidogenic enzymes, but not for the electron transfer proteins or for the components of the cholesterol import machine.
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Affiliation(s)
- Walter L Miller
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94143-1346, USA; Division of Endocrinology, University of California San Francisco, San Francisco, CA 94143-1346, USA.
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195
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Rajapaksha M, Kaur J, Bose M, Whittal RM, Bose HS. Cholesterol-mediated conformational changes in the steroidogenic acute regulatory protein are essential for steroidogenesis. Biochemistry 2013; 52:7242-53. [PMID: 24053410 DOI: 10.1021/bi401125v] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although the mechanism by which the steroidogenic acute regulatory protein (StAR) promotes steroidogenesis has been studied extensively, it remains incompletely characterized. Because structural analysis has revealed a hydrophobic sterol-binding pocket (SBP) within StAR, this study sought to examine the regulatory role of cholesterol concentrations on protein folding and mitochondrial import. Stopped-flow analyses revealed that at low concentrations, cholesterol promotes StAR folding. With increasing cholesterol concentrations, an intermediate state is reached followed by StAR unfolding. With 5 μg/mL cholesterol, the apparent binding was 0.011 s(-1), and the unfolding time (t1/2) was 63 s. The apparent binding increased from 0.036 to 0.049 s(-1) when the cholesterol concentration was increased from 50 μg/mL to 100 μg/mL while t1/2 decreased from 19 to 14 s. These cholesterol-induced conformational changes were not mediated by chemical chaperones. Protein fingerprinting analysis of StAR in the absence and presence of cholesterol by mass spectrometry revealed that the cholesterol binding region, comprising amino acids 132-188, is protected from proteolysis. In the absence of cholesterol, a longer region of amino acids from position 62 to 188 was protected, which is suggestive of organization into smaller, tightly folded regions with cholesterol. In addition, rapid cholesterol metabolism was required for the import of StAR into the mitochondria, suggesting that the mitochondria have a limited capacity for import and processing of steroidogenic proteins, which is dependent on cholesterol storage. Thus, cholesterol regulates StAR conformation, activating it to an intermediate flexible state for mitochondrial import and its enhanced cholesterol transfer capacity.
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Affiliation(s)
- Maheshinie Rajapaksha
- Department of Biochemistry, Division of Biomedical Sciences, Mercer University School of Medicine , Savannah, Georgia 31404, United States
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196
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Morohaku K, Phuong NS, Selvaraj V. Developmental expression of translocator protein/peripheral benzodiazepine receptor in reproductive tissues. PLoS One 2013; 8:e74509. [PMID: 24040265 PMCID: PMC3764105 DOI: 10.1371/journal.pone.0074509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/02/2013] [Indexed: 12/20/2022] Open
Abstract
Translocator protein (TSPO) present in the outer mitochondrial membrane has been suggested to be critical for cholesterol import, a rate-limiting step for steroid hormone biosynthesis. Despite the importance of steroidogenesis in regulating reproductive functions, the developmental profile of TSPO expression in the gonads and accessory sex organs has not been completely characterized. As a first step towards understanding the function of TSPO, we studied its expression in male and female murine reproductive organs. We examined testes and ovaries at embryonic days 14.5 and 18.5, and postnatal days 0, 7, 14, 21 and 56 of development. In the adult testis, TSPO was expressed in both Leydig cells and Sertoli cells. In the developing testes TSPO expression was seen in immature Sertoli cells, fetal Leydig cells and gonocytes. In the ovary, TSPO was expressed in the ovarian surface epithelium, interstitial cells granulosa cells and luteal cells. Corpora lutea of ovaries from pregnant mice showed strong expression of TSPO. In the developing ovary, TSPO expression was seen in the squamous pregranulosa cells associated with germ line cysts, together with progressively increasing expression in interstitial cells and the ovarian surface epithelium. In adult mice, the epithelia of other reproductive tissues like the epididymis, prostate, seminal vesicle, oviduct and uterus also showed distinct patterns of TSPO expression. In summary, TSPO expression in both male and female reproductive tissues was not only restricted to steroidogenic cells. Expression in Sertoli cells, ovarian surface epithelium, efferent ductal epithelium, prostatic epithelium, seminal vesiclular epithelium, uterine epithelium and oviductal epithelium suggest either previously unknown sites for de novo steroidogenesis or functions for TSPO distinct from its well-studied role in steroid hormone production.
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Affiliation(s)
- Kanako Morohaku
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
| | - Newton S. Phuong
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
| | - Vimal Selvaraj
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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197
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Anuka E, Yivgi-Ohana N, Eimerl S, Garfinkel B, Melamed-Book N, Chepurkol E, Aravot D, Zinman T, Shainberg A, Hochhauser E, Orly J. Infarct-induced steroidogenic acute regulatory protein: a survival role in cardiac fibroblasts. Mol Endocrinol 2013; 27:1502-17. [PMID: 23831818 DOI: 10.1210/me.2013-1006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Steroidogenic acute regulatory protein (StAR) is indispensable for steroid hormone synthesis in the adrenal cortex and the gonadal tissues. This study reveals that StAR is also expressed at high levels in nonsteroidogenic cardiac fibroblasts confined to the left ventricle of mouse heart examined 3 days after permanent ligation of the left anterior descending coronary artery. Unlike StAR, CYP11A1 and 3β-hydroxysteroid dehydrogenase proteins were not observed in the postinfarction heart, suggesting an apparent lack of de novo cardiac steroidogenesis. Work with primary cultures of rat heart cells revealed that StAR is induced in fibroblasts responding to proapoptotic treatments with hydrogen peroxide or the kinase inhibitor staurosporine (STS). Such induction of StAR in culture was noted before spontaneous differentiation of the fibroblasts to myofibroblasts. STS induction of StAR in the cardiac fibroblasts conferred a marked resistance to apoptotic cell death. Consistent with that finding, down-regulation of StAR by RNA interference proportionally increased the number of STS-treated apoptotic cells. StAR down-regulation also resulted in a marked increase of BAX activation in the mitochondria, an event known to associate with the onset of apoptosis. Last, STS treatment of HeLa cells showed that apoptotic demise characterized by mitochondrial fission, cytochrome c release, and nuclear fragmentation is arrested in individual HeLa cells overexpressing StAR. Collectively, our in vivo and ex vivo evidence suggests that postinfarction expression of nonsteroidogenic StAR in cardiac fibroblasts has novel antiapoptotic activity, allowing myofibroblast precursor cells to survive the traumatized event, probably to differentiate and function in tissue repair at the infarction site.
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Affiliation(s)
- Eli Anuka
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 41904, Israel
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198
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Vasudevan L, Joshi R, Kumar Das D, Rao S, Sanghavi D, Babu S, Tamhankar PM. Identification of novel mutations in STAR gene in patients with lipoid congenital adrenal hyperplasia: a first report from India. J Clin Res Pediatr Endocrinol 2013; 5:121-4. [PMID: 23748066 PMCID: PMC3701918 DOI: 10.4274/jcrpe.927] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Lipoid congenital adrenal hyperplasia (LCAH), a rare disorder of steroid biosynthesis, is the most severe form of CAH. We report novel molecular findings of three unrelated infants with LCAH diagnosed at our center. A known missense mutation c.653C>T (p.A218V) and two novel mutations [premature termination c.441G>A (or p.W147X) and frameshift deletion c.del815G (or p.R272PfsX35)] were identified after complete sequencing of the STAR gene. Prenatal diagnosis was carried out for the family with mutation c.815delG by molecular testing wherein the fetus was found to be homozygous for the mutation. This is the first report of molecular diagnosis and prenatal testing for LCAH from India.
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Affiliation(s)
- Lakshmi Vasudevan
- Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai
| | - Rajesh Joshi
- Bai Jerbai Wadia Hospital for Children, Department of Pediatrics, Division of Pediatric Endocrinology, Parel, Mumbai
| | - Dhanjit Kumar Das
- Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai
| | - Sudha Rao
- Bai Jerbai Wadia Hospital for Children, Department of Pediatrics, Division of Pediatric Endocrinology, Parel, Mumbai
| | - Daksha Sanghavi
- Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai
| | - Shiny Babu
- Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai
| | - Parag M. Tamhankar
- Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai
,* Address for Correspondence: Genetic Research Center, National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai Phone: +91 22 24192037 E-mail:
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199
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Light A, Hammes SR. Membrane receptor cross talk in steroidogenesis: recent insights and clinical implications. Steroids 2013; 78:633-8. [PMID: 23380369 DOI: 10.1016/j.steroids.2012.12.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/17/2012] [Accepted: 12/31/2012] [Indexed: 11/19/2022]
Abstract
Steroid production by all three major steroidogenic tissues, the adrenals, testes, and ovaries, is critical for survival and reproduction of all animals. As such, the pathways that regulate steroidogenesis are conserved between these tissues, from the steroidogenic enzymes and cofactors that synthesize steroids, to the intracellular signaling molecules and Gαs-coupled receptors that mediate the activity of these enzymes. Recent work has revealed another important conserved pathway in steroidogenesis: crosstalk between membrane G protein-coupled receptors and membrane receptor tyrosine kinases. Luteinizing hormone (LH) or adrencorticotropic hormone (ACTH) binding to their cognate Gαs-coupled membrane receptors in the gonads and adrenals, respectively, leads to cAMP-induced trans-activation of the epidermal growth factor (EGF) receptor, followed by activation of Akt and Erk signaling. These kinase signals then activate Steroidogenic Acute Regulatory (StAR) protein, which promotes steroid production. Inhibition of this pathway abrogates both LH- and ACTH-induced steroidogenesis. Interestingly, LH-induced transactivation of the EGF receptor in the ovary uniquely requires matrix metalloproteinase-mediated release of EGF receptor ligands, and inhibition of these proteases blocks LH-induced steroidogenesis. Given this unique need for matrix metalloproteinases in ovarian steroidogenesis, MMP inhibition may prove to be useful when treating diseases of excess ovarian steroid production, such as polycystic ovary syndrome.
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Affiliation(s)
- Allison Light
- Division of Endocrinology and Metabolism, Department of Medicine, University of Rochester School of Medicine, 601 Elmwood Ave., Rochester, NY 14642, USA
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200
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Abstract
Arterial hypertension is a major cardiovascular risk factor that affects between 10 and 40% of the population in industrialized countries. Primary aldosteronism (PA) is the most common form of secondary hypertension with an estimated prevalence of around 10% in referral centers and 4% in a primary care setting. Despite its high prevalence until recently, the underlying genetic and molecular basis of this common disease had remained largely obscure. Over the past decade, a number of insights have been achieved that have relied on in vitro cellular systems, wild-type and genetically modified in vivo models, as well as clinical studies in well-characterized patient populations. This progress has been made possible by a number of independent technical developments including that of specific hormone assays that allow measurement in small sample volumes as well as genetic techniques that enable high-throughput sequencing of a large number of samples. Furthermore, animal models have provided important insights into the physiology of aldosterone regulation that have served as a starting point for investigation of mechanisms involved in autonomous aldosterone secretion. Finally, national and international networks that have built up registries and biobanks have been instrumental in fostering translational research endeavors in PA. Therefore, it is to be expected that in the near future, further pathophysiological mechanisms that result in autonomous aldosterone secretion will be unraveled.
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Affiliation(s)
- Felix Beuschlein
- Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ziemssenstrasse 1, D-80336 Munich, Germany.
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