1
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Sandor LF, Ragacs R, Gyori DS. Local Effects of Steroid Hormones within the Bone Microenvironment. Int J Mol Sci 2023; 24:17482. [PMID: 38139309 PMCID: PMC10744126 DOI: 10.3390/ijms242417482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Steroid hormone production via the adrenal cortex, gonads, and placenta (so-called glandular steroidogenesis) is responsible for the endocrine control of the body's homeostasis and is organized by a feedback regulatory mechanism based on the hypothalamus-pituitary-steroidogenic gland axis. On the other hand, recently discovered extraglandular steroidogenesis occurring locally in different tissues is instead linked to paracrine or autocrine signaling, and it is independent of the control by the hypothalamus and pituitary glands. Bone cells, such as bone-forming osteoblasts, osteoblast-derived osteocytes, and bone-resorbing osteoclasts, respond to steroid hormones produced by both glandular and extraglandular steroidogenesis. Recently, new techniques to identify steroid hormones, as well as synthetic steroids and steroidogenesis inhibitors, have been introduced, which greatly empowered steroid hormone research. Based on recent literature and new advances in the field, here we review the local role of steroid hormones in regulating bone homeostasis and skeletal lesion formation. The novel idea of extraglandular steroidogenesis occurring within the skeletal system raises the possibility of the development of new therapies for the treatment of bone diseases.
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Affiliation(s)
| | | | - David S. Gyori
- Department of Physiology, School of Medicine, Semmelweis University, 1085 Budapest, Hungary
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2
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Aghaei S, Farrokhi E, Saffari-Chaleshtori J, Hoseinzadeh M, Molavi N, Hashemipour M, Rostampour N, Asgharzadeh S, Tabatabaiefar MA. New molecular insights into the A218V variant impact on the steroidogenic acute regulatory protein (STAR) associated with 46, XY disorders of sexual development. Mol Genet Genomics 2023; 298:693-708. [PMID: 37004560 DOI: 10.1007/s00438-023-02006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/07/2023] [Indexed: 04/04/2023]
Abstract
Disorders of sexual development (DSD) are an abnormal congenital conditions associated with atypical development of the urogenital tract and external genital structures. The steroidogenic acute regulatory (STAR) gene, associated with congenital lipoid adrenal hyperplasia (CLAH), is included in the targeted gene panel for the DSD diagnosis. Therefore, the genetic alterations of the STAR gene and their molecular effect were examined in the CLAH patients affected with DSD. Ten different Iranian families including twelve male pseudo-hermaphroditism patients with CLAH phenotype were studied using genetic linkage screening and STAR gene sequencing in the linked families to the STAR locus. Furthermore, the structural, dynamical, and functional impacts of the variants on the STAR in silico were analyzed. Sanger sequencing showed the pathogenic variant p.A218V in STAR gene, as the first report in Iranian population. Moreover, modeling and simulation analysis were performed using tools such as radius of gyration, root mean square deviation (RMSD), root mean square fluctuation (RMSF), and molecular docking showed that p.A218V variant affects the residues interaction in cholesterol-binding site and the proper folding of STAR through increasing H-bound and the amount of α-Helix, deceasing total flexibility and changing fluctuations in some residues, resulting in reduced steroidogenic activity of the STAR protein. The study characterized the structural and functional changes of STAR caused by pathogenic variant p.A218V. It leads to limited cholesterol-binding activity of STAR, ultimately leading to the CLAH disease. Molecular dynamics simulation of STAR variants could help explain different clinical manifestations of CLAH disease.
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Affiliation(s)
- Shahrzad Aghaei
- Department of Molecular Medicine, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Effat Farrokhi
- Department of Molecular Medicine, School of Advanced Technologies, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Javad Saffari-Chaleshtori
- Clinical Biochemistry Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Marziyeh Hoseinzadeh
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Newsha Molavi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahin Hashemipour
- Metabolic Liver Disease Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Noushin Rostampour
- Metabolic Liver Disease Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Samira Asgharzadeh
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
- Department of Genetics and Molecular Biology, School of Medicine and Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Noncommunicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.
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3
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Liu J, Dai HM, Guang GP, Hu WM, Jin P. Clinical and functional analyses of the novel STAR c.558C>A in a patient with classic lipoid congenital adrenal hyperplasia. Front Genet 2023; 14:1096454. [PMID: 36733346 PMCID: PMC9887130 DOI: 10.3389/fgene.2023.1096454] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023] Open
Abstract
Objective: Congenital lipid adrenal hyperplasia (LCAH) is the most serious type of congenital adrenal hyperplasia and is caused by steroid-based acute regulatory (STAR) protein mutations. Herein, we report compound heterozygous mutations c.558C>A (p.S186 R) and c.772C>T (p.Q258*) in a newborn 46 XY patient diagnosed with classic LCAH and explore their clinical and functional characteristics. Methods: Peripheral blood samples were collected from LCAH patient and their families. The pathogenic variant identified by whole-exome sequencing was further confirmed by Sanger sequencing and pedigree verification. The functional consequence and ability to convert cholesterol into progesterone of the identified STAR Q258* and S186 R mutations were analyzed by cell transfection and in vitro assays. Results: The proband was presented with severe glucocorticoid and mineralocorticoid deficiency, high adrenocorticotropic hormone, and enlarged adrenals. Heterozygous mutations p. S186 R and p. Q258* in the STAR gene were identified in the patient, and her parents were carriers, which is consistent with an autosomal recessive disorder. The STAR p. Q258* mutation has been reported and generates a truncated protein. The p. S186 R mutation is a novel variant that disrupts STAR. The residual STAR activities of p. S186R, p. Q258*, and p. S186R/p.Q258* were 13.9%, 7.3%, and 11.2%, respectively, of the wild-type, proving the main negative effects of the mutant proteins. Conclusion: Our findings reveal the molecular mechanisms underlying LCAH pathogenesis, further expanding the genotype and clinical spectrum of LCAH.
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Affiliation(s)
- Jie Liu
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Hong-Mei Dai
- Department of Pediatric, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Gao-Peng Guang
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Wen-Mu Hu
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ping Jin
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China,*Correspondence: Ping Jin,
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4
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Role of STAR and SCP2/SCPx in the Transport of Cholesterol and Other Lipids. Int J Mol Sci 2022; 23:ijms232012115. [PMID: 36292972 PMCID: PMC9602805 DOI: 10.3390/ijms232012115] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/30/2022] [Accepted: 10/08/2022] [Indexed: 11/21/2022] Open
Abstract
Cholesterol is a lipid molecule essential for several key cellular processes including steroidogenesis. As such, the trafficking and distribution of cholesterol is tightly regulated by various pathways that include vesicular and non-vesicular mechanisms. One non-vesicular mechanism is the binding of cholesterol to cholesterol transport proteins, which facilitate the movement of cholesterol between cellular membranes. Classic examples of cholesterol transport proteins are the steroidogenic acute regulatory protein (STAR; STARD1), which facilitates cholesterol transport for acute steroidogenesis in mitochondria, and sterol carrier protein 2/sterol carrier protein-x (SCP2/SCPx), which are non-specific lipid transfer proteins involved in the transport and metabolism of many lipids including cholesterol between several cellular compartments. This review discusses the roles of STAR and SCP2/SCPx in cholesterol transport as model cholesterol transport proteins, as well as more recent findings that support the role of these proteins in the transport and/or metabolism of other lipids.
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5
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Zamalutdinova SV, Isaeva LV, Zamalutdinov AV, Faletrov YV, Rubtsov MA, Novikova LA. Analysis of Activity of Human Steroidogenic Acute Regulatory Protein (STARD1) Expressed in Escherichia coli Cells. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:1015-1020. [PMID: 36180996 DOI: 10.1134/s0006297922090127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/08/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
One of the main obstacles to the successful use of Escherichia coli cells for steroid transformation in biotechnological processes is inefficient transport of steroid substrates into the cells. Here, we tested the possibility of using human cholesterol transfer protein STARD1 (steroidogenic acute regulatory protein) to increase the efficiency of steroid uptake by bacterial cells. Genetic constructs were obtained for the synthesis in E. coli BL21 (DE3) cells of a truncated version of STARD1 containing protein functional domain (residues 66-285) and STARD1 (66-285)-GFP fusion protein, both carrying bacterial periplasmic targeting sequence pelB at the N-terminus. Analysis of preparations of E. coli/pET22b/STARD1-GFP cells by fluorimetry and Western blotting confirmed that the used expression system ensured the synthesis of the heterologous protein. Using fluorescence spectroscopy, it was demonstrated that the presence of STARD1 in the cells increased the efficiency of assimilation of NBD-labeled cholesterol analogues by E. coli/pET22b/STARD1 cells 1.3-1.6 times (p < 0.05) compared to the wild-type cells, thus demonstrating that human STARD1 exhibits its functional activity in bacterial cells. This opens prospects for optimizing and using a fundamentally new approach to increase the efficiency of steroid uptake by cells - the inclusion of a specific carrier protein in the cell membrane, which can expand the arsenal of methods used to obtain strains of microorganisms for synthesis.
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Affiliation(s)
| | - Ludmila V Isaeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | | | - Yaroslav V Faletrov
- Research Institute for Physical Chemical Problems, Belarusian State University, Minsk, 220030, Belarus.
| | - Mikhail A Rubtsov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Sechenov First Moscow State Medical University, Moscow, 119991, Russia
| | - Ludmila A Novikova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
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6
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Galano M, Papadopoulos V. Role of Constitutive STAR in Mitochondrial Structure and Function in MA-10 Leydig Cells. Endocrinology 2022; 163:6608928. [PMID: 35704520 DOI: 10.1210/endocr/bqac091] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Indexed: 11/19/2022]
Abstract
The steroidogenic acute regulatory protein (STAR; STARD1) is critical for the transport of cholesterol into the mitochondria for hormone-induced steroidogenesis. Steroidogenic cells express STAR under control conditions (constitutive STAR). On hormonal stimulation, STAR localizes to the outer mitochondrial membrane (OMM) where it facilitates cholesterol transport and where it is processed to its mature form. Here, we show that knockout of Star in MA-10 mouse tumor Leydig cells (STARKO1) causes defects in mitochondrial structure and function under basal conditions. We also show that overexpression of Star in STARKO1 cells exacerbates, rather than recovers, mitochondrial structure and function, which further disrupts the processing of STAR at the OMM. Our findings suggest that constitutive STAR is necessary for proper mitochondrial structure and function and that mitochondrial dysfunction leads to defective STAR processing at the OMM.
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Affiliation(s)
- Melanie Galano
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089, USA
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089, USA
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7
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Mechanism of Action of an Environmentally Relevant Organochlorine Mixture in Repressing Steroid Hormone Biosynthesis in Leydig Cells. Int J Mol Sci 2022; 23:ijms23073997. [PMID: 35409357 PMCID: PMC8999779 DOI: 10.3390/ijms23073997] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/28/2022] [Accepted: 04/01/2022] [Indexed: 02/04/2023] Open
Abstract
Within Leydig cells, steroidogenesis is induced by the pituitary luteinizing hormone (LH). The binding of LH to its receptor increases cAMP production, which then activates the expression of genes involved in testosterone biosynthesis. One of these genes codes for the steroidogenic acute regulatory (STAR) protein. STAR is part of a complex that shuttles cholesterol, the precursor of all steroid hormones, through the mitochondrial membrane where steroidogenesis is initiated. Organochlorine chemicals (OCs) are environmental persistent organic pollutants that are found at high concentrations in Arctic areas. OCs are known to affect male reproductive health by decreasing semen quality in different species, including humans. We previously showed that an environmentally relevant mixture of OCs found in Northern Quebec disrupts steroidogenesis by decreasing STAR protein levels without affecting the transcription of the gene. We hypothesized that OCs might affect STAR protein stability. To test this, MA-10 Leydig cell lines were incubated for 6 h with vehicle or the OCs mixture in the presence or absence of 8Br-cAMP with or without MG132, an inhibitor of protein degradation. We found that MG132 prevented the OC-mediated decrease in STAR protein levels following 8Br-cAMP stimulation. However, progesterone production was still decreased by the OC mixture, even in the presence of MG132. This suggested that proteins involved in steroid hormone production in addition to STAR are also affected by the OC mixture. To identify these proteins, a whole cell approach was used and total proteins from MA-10 Leydig cells exposed to the OC mixture with or without stimulation with 8Br-cAMP were analyzed by 2D SDS-PAGE and LC-MS/MS. Bioinformatics analyses revealed that several proteins involved in numerous biological processes are affected by the OC mixture, including proteins involved in mitochondrial transport, lipid metabolism, and steroidogenesis.
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8
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The Expanding Role of Mitochondria, Autophagy and Lipophagy in Steroidogenesis. Cells 2021; 10:cells10081851. [PMID: 34440620 PMCID: PMC8391558 DOI: 10.3390/cells10081851] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
The fundamental framework of steroidogenesis is similar across steroidogenic cells, especially in initial mitochondrial steps. For instance, the START domain containing protein-mediated cholesterol transport to the mitochondria, and its conversion to pregnenolone by the enzyme P450scc, is conserved across steroidogenic cells. The enzyme P450scc localizes to the inner mitochondrial membrane, which makes the mitochondria essential for steroidogenesis. Despite this commonality, mitochondrial structure, number, and dynamics vary substantially between different steroidogenic cell types, indicating implications beyond pregnenolone biosynthesis. This review aims to focus on the growing roles of mitochondria, autophagy and lipophagy in cholesterol uptake, trafficking and homeostasis in steroidogenic cells and consequently in steroidogenesis. We will focus on these aspects in the context of the physiological need for different steroid hormones and cell-intrinsic inherent features in different steroidogenic cell types beyond mitochondria as a mere site for the beginning of steroidogenesis. The overall goal is to provide an authentic and comprehensive review on the expanding role of steroidogenic cell-intrinsic processes in cholesterol homeostasis and steroidogenesis, and to bring attention to the scientific community working in this field on these promising advancements. Moreover, we will discuss a novel mitochondrial player, prohibitin, and its potential role in steroidogenic mitochondria and cells, and consequently, in steroidogenesis.
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9
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Chakraborty S, Pramanik J, Mahata B. Revisiting steroidogenesis and its role in immune regulation with the advanced tools and technologies. Genes Immun 2021; 22:125-140. [PMID: 34127827 PMCID: PMC8277576 DOI: 10.1038/s41435-021-00139-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/03/2021] [Accepted: 05/21/2021] [Indexed: 12/19/2022]
Abstract
Historically tools and technologies facilitated scientific discoveries. Steroid hormone research is not an exception. Unfortunately, the dramatic advancement of the field faded this research area and flagged it as a solved topic. However, it should have been the opposite. The area should glitter with its strong foundation and attract next-generation scientists. Over the past century, a myriad of new facts on biochemistry, molecular biology, cell biology, physiology and pathology of the steroid hormones was discovered. Several innovations were made and translated into life-saving treatment strategies such as synthetic steroids, and inhibitors of steroidogenesis and steroid signaling. Steroid molecules exhibit their diverse effects on cell metabolism, salt and water balance, development and function of the reproductive system, pregnancy, and immune-cell function. Despite vigorous research, the molecular basis of the immunomodulatory effect of steroids is still mysterious. The recent excitement on local extra-glandular steroidogenesis in regulating inflammation and immunity is revitalizing the topic with a new perspective. Therefore, here we review the role of steroidogenesis in regulating inflammation and immunity, discuss the unresolved questions, and how this area can bring another golden age of steroid hormone research with the development of new tools and technologies and advancement of the scientific methods.
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Affiliation(s)
| | - Jhuma Pramanik
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Bidesh Mahata
- Department of Pathology, University of Cambridge, Cambridge, UK.
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10
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Chen H, Xin X, Liu M, Ma F, Yu Y, Huang J, Dai H, Li Z, Ge RS. In utero exposure to dipentyl phthalate disrupts fetal and adult Leydig cell development. Toxicol Appl Pharmacol 2021; 419:115514. [PMID: 33798595 DOI: 10.1016/j.taap.2021.115514] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/23/2021] [Accepted: 03/27/2021] [Indexed: 01/20/2023]
Abstract
Phthalates as plasticizers are widely used in many consumer products. Dipentyl phthalate (DPeP) is one of phthalates. However, there are currently few data on whether DPeP exposure affects rat Leydig cell development. In this study, we investigated the effects of in utero DPeP exposure on Leydig cell development in the testes of male newborn and adult rats. From gestational days 14 to 21, Sprague-Dawley pregnant rats were gavaged vehicle (corn oil, control) or DPeP (10, 50, 100, and 500 mg/kg body weight/day). Testosterone and the expression of Leydig cell genes and proteins in the testis at birth and at postnatal day 56 were examined. DPeP dose-dependently reduced serum testosterone levels of male offspring at birth and at postnatal day 56 at 100 and 500 mg/kg and lowered serum luteinizing hormone levels at adult males at ≥10 mg/kg when compared with the control. In addition, DPeP increased number of fetal Leydig cells by inducing their proliferation but down-regulated the expression of Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, and Insl3 in fetal Leydig cells per se. DPeP reduced number of adult Leydig cells by inducing cell apoptosis and down-regulated the expression of Lhcgr and Star in adult Leydig cells at postnatal day 56. DPeP lowered SIRT1 and BCL2 levels in the testis of adult rats. In conclusion, DPeP adversely affects both fetal and adult Leydig cell development after in utero exposure.
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Affiliation(s)
- Haiqiong Chen
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiu Xin
- Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Miaoqing Liu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Feifei Ma
- Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yige Yu
- Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jie Huang
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Haipeng Dai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhongrong Li
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - Ren-Shan Ge
- Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
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11
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Leydig cell aging: Molecular mechanisms and treatments. VITAMINS AND HORMONES 2021; 115:585-609. [PMID: 33706963 DOI: 10.1016/bs.vh.2020.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Late-onset hypogonadism, resulting from deficiency in serum testosterone (T), affects the health and quality of life of millions of aging men. T is synthesized by Leydig cells (LCs) in response to luteinizing hormone (LH). LH binds LC plasma membrane receptors, inducing the formation of a supramolecular complex of cytosolic and mitochondrial proteins, the Steroidogenic InteracTomE (SITE). SITE proteins are involved in targeting cholesterol to CYP11A1 in the mitochondria, the first enzyme of the steroidogenic cascade. Cholesterol translocation is the rate-determining step in T formation. With aging, LC defects occur that include changes in SITE, an increasingly oxidative intracellular environment, and reduced androgen formation and serum T levels. T replacement therapy (TRT) will restore T levels, but reported side effects make it desirable to develop additional strategies for increasing T. One approach is to target LC protein-protein interactions and thus increase T production by the hypofunctional Leydig cells themselves.
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12
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Koganti PP, Selvaraj V. Lack of adrenal TSPO/PBR expression in hamsters reinforces correlation to triglyceride metabolism. J Endocrinol 2020; 247:1-10. [PMID: 32698131 PMCID: PMC8011561 DOI: 10.1530/joe-20-0189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/13/2020] [Indexed: 11/08/2022]
Abstract
Despite being a highly conserved protein, the precise role of the mitochondrial translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), remains elusive. The void created by studies that overturned a presumptive model that described TSPO/PBR as a mitochondrial cholesterol transporter for steroidogenesis has been filled with evidence that it can affect mitochondrial metabolic functions across different model systems. We previously reported that TSPO/PBR deficient steroidogenic cells upregulate mitochondrial fatty acid oxidation and presented a strong positive correlation between TSPO/PBR expression and tissues active in triglyceride metabolism or lipid storage. Nevertheless, the highlighting of inconsistencies in prior work has provoked reprisals that threaten to stifle progress. One frequent factoid presented as being supportive of a cholesterol import function is that there are no steroid-synthesizing cell types without high TSPO/PBR expression. In this study, we examine the hamster adrenal gland that is devoid of lipid droplets in the cortex and largely relies on de novo cholesterol biosynthesis and uptake for steroidogenesis. We find that Tspo expression in the hamster adrenal is imperceptible compared to the mouse. This observation is consistent with a substantially low expression of Cpt1a in the hamster adrenal, indicating minimal mitochondrial fatty acid oxidation capacity compared to the mouse. These findings provide further reinforcement that the much sought-after mechanism of TSPO/PBR function remains correlated with the extent of cellular triglyceride metabolism. Thus, TSPO/PBR could have a homeostatic function relevant only to steroidogenic systems that manage triglycerides associated with lipid droplets.
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Affiliation(s)
- Prasanthi P. Koganti
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853
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13
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Czuchlej SC, Volonteri MC, Scaia MF, Ceballos NR. Characterization of StAR protein of Rhinella arenarum (Amphibia, Anura). Gen Comp Endocrinol 2020; 295:113535. [PMID: 32535173 DOI: 10.1016/j.ygcen.2020.113535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/13/2020] [Accepted: 06/06/2020] [Indexed: 10/24/2022]
Abstract
The steroidogenic acute regulatory (StAR) protein performs the delivery of cholesterol from the outer to inner mitochondrial membrane. This is considered the rate-limiting step of acute steroid production, widely studied in mammals. However, there are only few reports regarding the characterization and expression of StAR protein in non-mammalian vertebrates. In this study, StAR protein sequence of Rhinella arenarum has been characterized and deduced from interrenal and testis cDNA sequences. StAR encodes a 285 amino acid protein with a conserved domain containing putative lipid binding sites. In vitro incubations showed that expression of StAR mRNA in testis, determined by qPCR, and testosterone synthesis determined by radioimmunoassay were stimulated after treatment with hCG and 8Br-cAMP. However, StAR mRNA expression results obtained with hCG show a higher stimulation than those obtained with 8Br-cAMP, even though steroidogenic production is the same with both treatments.
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Affiliation(s)
- Silvia Cristina Czuchlej
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina.
| | - María Clara Volonteri
- Instituto de Diversidad y Evolución Austral (IDEAus CENPAT-CONICET). Puerto Madryn, Chubut, Argentina.
| | - María Florencia Scaia
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Nora Raquel Ceballos
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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14
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Tugaeva KV, Titterington J, Sotnikov DV, Maksimov EG, Antson AA, Sluchanko NN. Molecular basis for the recognition of steroidogenic acute regulatory protein by the 14‐3‐3 protein family. FEBS J 2020; 287:3944-3966. [DOI: 10.1111/febs.15474] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/26/2020] [Accepted: 07/01/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Kristina V. Tugaeva
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biochemistry School of Biology M.V. Lomonosov Moscow State University Russia
| | - James Titterington
- York Structural Biology Laboratory Department of Chemistry University of York UK
| | - Dmitriy V. Sotnikov
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
| | - Eugene G. Maksimov
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biophysics School of Biology M.V. Lomonosov Moscow State University Russia
| | - Alfred A. Antson
- York Structural Biology Laboratory Department of Chemistry University of York UK
| | - Nikolai N. Sluchanko
- Federal Research Center of Biotechnology of the Russian Academy of Sciences A.N. Bach Institute of Biochemistry Moscow Russia
- Department of Biophysics School of Biology M.V. Lomonosov Moscow State University Russia
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15
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Clark BJ. The START-domain proteins in intracellular lipid transport and beyond. Mol Cell Endocrinol 2020; 504:110704. [PMID: 31927098 DOI: 10.1016/j.mce.2020.110704] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 12/17/2022]
Abstract
The Steroidogenic Acute Regulatory Protein-related Lipid Transfer (START) domain is a ~210 amino acid sequence that folds into an α/β helix-grip structure forming a hydrophobic pocket for lipid binding. The helix-grip fold structure defines a large superfamily of proteins, and this review focuses on the mammalian START domain family members that include single START domain proteins with identified ligands, and larger multi-domain proteins that may have novel roles in metabolism. Much of our understanding of the mammalian START domain proteins in lipid transport and changes in metabolism has advanced through studies using knockout mouse models, although for some of these proteins the identity and/or physiological role of ligand binding remains unknown. The findings that helped define START domain lipid-binding specificity, lipid transport, and changes in metabolism are presented to highlight that fundamental questions remain regarding the biological function(s) for START domain-containing proteins.
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Affiliation(s)
- Barbara J Clark
- Department of Biochemistry & Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
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16
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Tugaeva KV, Sluchanko NN. Steroidogenic Acute Regulatory Protein: Structure, Functioning, and Regulation. BIOCHEMISTRY (MOSCOW) 2019; 84:S233-S253. [PMID: 31213205 DOI: 10.1134/s0006297919140141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Steroidogenesis takes place mainly in adrenal and gonadal cells that produce a variety of structurally similar hormones regulating numerous body functions. The rate-limiting stage of steroidogenesis is cholesterol delivery to the inner mitochondrial membrane, where it is converted by cytochrome P450scc into pregnenolone, a common precursor of all steroid hormones. The major role of supplying mitochondria with cholesterol belongs to steroidogenic acute regulatory protein (STARD1). STARD1, which is synthesized de novo as a precursor containing mitochondrial localization sequence and sterol-binding domain, significantly accelerates cholesterol transport and production of pregnenolone. Despite a tremendous interest in STARD1 fueled by its involvement in hereditary diseases and extensive efforts of numerous laboratories worldwide, many aspects of STARD1 structure, functioning, and regulation remain obscure and debatable. This review presents current concepts on the structure of STARD1 and other lipid transfer proteins, the role of STARD1 in steroidogenesis, and the mechanism of its functioning, as well as identifies the most controversial and least studied questions related to the activity of this protein.
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Affiliation(s)
- K V Tugaeva
- Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia. .,Lomonosov Moscow State University, Biological Faculty, Department of Biochemistry, Moscow, 119234, Russia
| | - N N Sluchanko
- Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia. .,Lomonosov Moscow State University, Biological Faculty, Department of Biophysics, Moscow, 119991, Russia
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17
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Zhao X, Su Z, Liu X, Song J, Gan Y, Wen P, Li S, Wang L, Pan L. Long-term follow-up in a Chinese child with congenital lipoid adrenal hyperplasia due to a StAR gene mutation. BMC Endocr Disord 2018; 18:78. [PMID: 30400872 PMCID: PMC6219181 DOI: 10.1186/s12902-018-0307-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/15/2018] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Congenital lipoid adrenal hyperplasia (CLAH) is an extremely rare and the most severe form of congenital adrenal hyperplasia. Typical features include disorder of sex development, early-onset adrenal crisis and enlarged adrenal glands with fatty accumulation. CASE PRESENTATION We report a case of CLAH caused by mutations in the steroidogenic acute regulatory protein (StAR) gene. The patient had typical early-onset adrenal crisis at 2 months of age. She had normal-appearing female genitalia and a karyotype of 46, XY. The serum cortisol and adrenal steroids levels were always nearly undetectable, but the adrenocorticotropic hormone levels were extremely high. Genetic analysis revealed compound heterozygous mutations at c. 229C > T (p.Q77X) in exon 3 and c. 722C > T (p.Q258X) in exon 7 of the StAR gene. The former mutation was previously detected in only two other Chinese CLAH patients. Both mutations cause truncation of the StAR protein. The case reported here appears to be a classic example of CLAH with very small adrenal glands and is the second reported CLAH case with small adrenal glands thus far. In a 15-year follow-up, the patient's height was approximately average for females before age 4 and fell to - 1 SDS at 10 years of age. Her bone age was similar to her chronological age from age 4 to age 15 years. CONCLUSIONS In conclusion, this is a classic case of CLAH with exceptionally small adrenal glands. Q77X mutation seems to be more common in Chinese CLAH patients. Additionally, this is the first report of the growth pattern associated with CLAH after a 15-year follow-up.
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MESH Headings
- Adolescent
- Adrenal Hyperplasia, Congenital/diagnosis
- Adrenal Hyperplasia, Congenital/genetics
- Adrenal Hyperplasia, Congenital/surgery
- Amino Acid Sequence
- Asian People/genetics
- Child
- Child, Preschool
- Disorder of Sex Development, 46,XY/diagnosis
- Disorder of Sex Development, 46,XY/genetics
- Disorder of Sex Development, 46,XY/surgery
- Female
- Follow-Up Studies
- Humans
- Infant
- Mutation/genetics
- Phosphoproteins/genetics
- Time Factors
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Affiliation(s)
- Xiu Zhao
- Department of Endocrinology, Shenzhen Children’s Hospital, 7019# Yitian Road, Futian District, Shenzhen, 518038 Guangdong Province China
| | - Zhe Su
- Department of Endocrinology, Shenzhen Children’s Hospital, 7019# Yitian Road, Futian District, Shenzhen, 518038 Guangdong Province China
| | - Xia Liu
- Department of Endocrinology, Shenzhen Children’s Hospital, 7019# Yitian Road, Futian District, Shenzhen, 518038 Guangdong Province China
| | - Jianming Song
- Pathology Department, Shenzhen Children’s Hospital, Shenzhen, 518038 China
| | - Yungen Gan
- Radiology Department, Shenzhen Children’s Hospital, Shenzhen, 518038 China
| | - Pengqiang Wen
- Pediatrics Research Institute, Shenzhen Children’s Hospital, Shenzhen, 518038 China
| | - Shoulin Li
- Department of Urology, Shenzhen Children’s Hospital, Shenzhen, 518038 China
| | - Li Wang
- Department of Endocrinology, Shenzhen Children’s Hospital, 7019# Yitian Road, Futian District, Shenzhen, 518038 Guangdong Province China
| | - Lili Pan
- Department of Endocrinology, Shenzhen Children’s Hospital, 7019# Yitian Road, Futian District, Shenzhen, 518038 Guangdong Province China
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18
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Deng B, Shen WJ, Dong D, Azhar S, Kraemer FB. Plasma membrane cholesterol trafficking in steroidogenesis. FASEB J 2018; 33:1389-1400. [PMID: 30133326 DOI: 10.1096/fj.201800697rrr] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cholesterol is an important component of plasma membranes (PMs) and the precursor of all steroid hormones. In steroidogenic tissues, upon hormone stimulation, there is a rapid transfer of cholesterol to the mitochondria, which is the site of the initial step in steroidogenesis. In the current study, we examined PM cholesterol trafficking for steroidogenesis. In a mitochondrial reconstitution assay, adrenal PMs supported steroidogenesis in the absence of additional transport proteins. Depletion of cholesterol in PMs by 50% eliminated the membranes' ability to support steroidogenesis in vitro and reduced steroid production in intact Y1 adrenocortical cells. Syntaxin (STX)-5 and α-soluble N-ethylmaleimide-sensitive factor attachment protein (α-SNAP) are enriched in adrenal PMs, and adrenocorticotropic hormone treatment of rats recruited STX5 and α-SNAP to adrenal PMs and mitochondria. Immunodepletion of STX5 and α-SNAP from PMs decreased steroidogenesis supported by PMs in vitro. Protease digestion of PMs decreased, whereas recombinant STX5 or α-SNAP restored, the PMs' ability to support steroidogenesis. Knockdown of either STX5 or α-SNAP in Y1 cells decreased stimulated steroidogenesis. These results indicate that STX5 and α-SNAP facilitate cholesterol trafficking from PMs to mitochondria for adrenal steroid synthesis and underscore the importance of vesicular trafficking of PM cholesterol for steroidogenesis.-Deng, B., Shen, W.-J., Dong, D., Azhar, S., Kraemer, F. B. Plasma membrane cholesterol trafficking in steroidogenesis.
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Affiliation(s)
- Bing Deng
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA; and.,Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA; and
| | - Dachuan Dong
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA; and
| | - Salman Azhar
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA; and
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology, and Metabolism, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA; and
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19
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Selvaraj V, Stocco DM, Clark BJ. Current knowledge on the acute regulation of steroidogenesis. Biol Reprod 2018; 99:13-26. [PMID: 29718098 PMCID: PMC6044331 DOI: 10.1093/biolre/ioy102] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/23/2018] [Accepted: 04/26/2018] [Indexed: 12/31/2022] Open
Abstract
How rapid induction of steroid hormone biosynthesis occurs in response to trophic hormone stimulation of steroidogenic cells has been a subject of intensive investigation for approximately six decades. A key observation made very early was that acute regulation of steroid biosynthesis required swift and timely synthesis of a new protein whose role appeared to be involved in the delivery of the substrate for all steroid hormones, cholesterol, from the outer to the inner mitochondrial membrane where the process of steroidogenesis begins. It was quickly learned that this transfer of cholesterol to the inner mitochondrial membrane was the regulated and rate-limiting step in steroidogenesis. Following this observation, the quest for this putative regulator protein(s) began in earnest in the late 1950s. This review provides a history of this quest, the candidate proteins that arose over the years and facts surrounding their rise or decline. Only two have persisted-translocator protein (TSPO) and the steroidogenic acute regulatory protein (StAR). We present a detailed summary of the work that has been published for each of these two proteins, the specific data that has appeared in support of their role in cholesterol transport and steroidogenesis, and the ensuing observations that have arisen in recent years that have refuted the role of TSPO in this process. We believe that the only viable candidate that has been shown to be indispensable is the StAR protein. Lastly, we provide our view on what may be the most important questions concerning the acute regulation of steroidogenesis that need to be asked in future.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Douglas M Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky, USA
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20
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Alswailem MM, Alzahrani OS, Alhomaidah DS, Alasmari R, Qasem E, Murugan AK, Alsagheir A, Brema I, Abbas BB, Almehthel M, Almeqbali A, Alzahrani AS. Mutational analysis of rare subtypes of congenital adrenal hyperplasia in a highly inbred population. Mol Cell Endocrinol 2018; 461:105-111. [PMID: 28870780 DOI: 10.1016/j.mce.2017.08.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/30/2017] [Accepted: 08/31/2017] [Indexed: 11/16/2022]
Abstract
CONTEXT Apart from 21 Hydroxylase deficiency, other subtypes of congenital adrenal hyperplasia (CAH) are rare. We studied the clinical features and molecular genetics of a relatively large series of patients with CYP17A1, HSD3β2 and StAR deficiencies. PATIENTS AND METHODS We studied 21 patients including 7 patients with CYP17A1, 10 patients with HSD3β2 and 4 patients with StAR deficiencies. For mutation detection, we isolated DNA from peripheral leucocytes, amplified genes of interest using polymerase chain reaction and directly sequenced the amplicons using Dideoxy Chain Termination method. RESULTS Regardless of their karyotype, patients with CYP17A1 deficiency presented with normally looking external female genitalia and were raised as females. Hypertension and hypokalemia were prominent features in 4 of 7 patients. Two missense (p.R416H, p.R239Q) and 2 non-sense (p.Y329X, p.Y329X) mutations were found in these 7 cases. In 3 unrelated families with 10 affected siblings with HSD3β2 mutations, two non-sense mutations were found (p.Q334X, p.R335X). 46XY patients with HSD3β2 deficiency presented with ambiguous genitalia while 46XX patients presented with normal female external genitalia. Adrenal crisis was common in patients with both karyotypes. In the 4 patients with StAR deficiency, both genetic male and female patients presented with normally looking female external genitalia and adrenal crisis. One previously reported missense mutation (p.R182H) was found in 3 unrelated patients and a novel non-sense mutation (p.Q264X) in the fourth patient. CONCLUSIONS These cases of rare subtypes of CAH illustrate the heterogeneous phenotypic and genetic features of these subtypes and add unique novel mutations to the previously known ones.
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Affiliation(s)
- Meshael M Alswailem
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Ohoud S Alzahrani
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Doha S Alhomaidah
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Rahma Alasmari
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Ebtesam Qasem
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | | | - Afaf Alsagheir
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Imad Brema
- Department of Medicine, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Bassam Ben Abbas
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Mohammed Almehthel
- Department of Medicine, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Ali Almeqbali
- National Diabetic and Endocrine Center, Muscat, Oman
| | - Ali S Alzahrani
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia; Department of Medicine, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.
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21
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Fan J, Wang K, Zirkin B, Papadopoulos V. CRISPR/Cas9‒Mediated Tspo Gene Mutations Lead to Reduced Mitochondrial Membrane Potential and Steroid Formation in MA-10 Mouse Tumor Leydig Cells. Endocrinology 2018; 159:1130-1146. [PMID: 29300865 PMCID: PMC5793793 DOI: 10.1210/en.2017-03065] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 12/21/2017] [Indexed: 12/17/2022]
Abstract
The outer mitochondrial membrane translocator protein (TSPO) binds cholesterol with high affinity and is involved in mediating its delivery into mitochondria, the rate-limiting step in hormone-induced steroidogenesis. Specific ligand binding to TSPO has been shown to initiate steroid formation. However, recent studies of the genetic deletion of Tspo have provided conflicting results. Here, we address and extend previous studies by examining the effects of Tspo-specific mutations on steroid formation in hormone- and cyclic adenosine monophosphate (cAMP)-responsive MA-10 cells, using the CRISPR/Cas9 system. Two mutant subcell lines, nG1 and G2G, each carrying a Tspo exon2-specific genome modification, and two control subcell lines, G1 and HH, each carrying a wild-type Tspo, were produced. In response to dibutyryl cAMP, the nG1 and G2G cells produced progesterone at levels significantly lower than those produced by the corresponding control cells G1 and HH. Neutral lipid homeostasis, which provides free cholesterol for steroid biosynthesis, was altered significantly in the Tspo mutant cells. Interestingly, the mitochondrial membrane potential (ΔΨm) of the Tspo mutant cells was significantly reduced compared with that of the control cells, likely because of TSPO interactions with the voltage-dependent anion channel and tubulin at the outer mitochondrial membrane. Steroidogenic acute regulatory protein (STAR) expression was induced in nG1 cells, suggesting that reduced TSPO affected STAR synthesis and/or processing. Taken together, these results provide further evidence for the critical role of TSPO in steroid biosynthesis and suggest that it may function at least in part via its regulation of ΔΨm and effects on STAR.
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Affiliation(s)
- Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Kevin Wang
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089
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22
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Tugaeva KV, Faletrov YV, Allakhverdiev ES, Shkumatov VM, Maksimov EG, Sluchanko NN. Effect of the NBD-group position on interaction of fluorescently-labeled cholesterol analogues with human steroidogenic acute regulatory protein STARD1. Biochem Biophys Res Commun 2018; 497:58-64. [DOI: 10.1016/j.bbrc.2018.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/02/2018] [Indexed: 10/18/2022]
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23
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Sluchanko NN, Tugaeva KV, Maksimov EG. Solution structure of human steroidogenic acute regulatory protein STARD1 studied by small-angle X-ray scattering. Biochem Biophys Res Commun 2017; 489:445-450. [DOI: 10.1016/j.bbrc.2017.05.167] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 05/28/2017] [Indexed: 12/11/2022]
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24
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Wang Y, Chen F, Ye L, Zirkin B, Chen H. Steroidogenesis in Leydig cells: effects of aging and environmental factors. Reproduction 2017; 154:R111-R122. [PMID: 28747539 DOI: 10.1530/rep-17-0064] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/14/2017] [Accepted: 07/26/2017] [Indexed: 12/28/2022]
Abstract
Serum testosterone (TS) levels decrease with aging in both humans and rodents. Using the rat as a model system, it was found that age-related reductions in serum TS were not due to loss of Leydig cells, but rather to the reduced ability of the Leydig cells to produce TS in response to luteinizing hormone (LH). Detailed analyses of the steroidogenic pathway have suggested that two defects along the pathway, LH-stimulated cAMP production and cholesterol transport to and into the mitochondria, are of particular importance in age-related reductions in TS production. Although the mechanisms involved in these defects are far from certain, increasing oxidative stress appears to play a particularly important role. Interestingly, increased oxidative stress also appears to be involved in the suppressive effects of endocrine disruptors on Leydig cell TS production.
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Affiliation(s)
- Yiyan Wang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhou, Zhejiang, China.,Department of Biochemistry and Molecular BiologyJohns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Fenfen Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhou, Zhejiang, China
| | - Leping Ye
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhou, Zhejiang, China
| | - Barry Zirkin
- Department of Biochemistry and Molecular BiologyJohns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Haolin Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhou, Zhejiang, China .,Department of Biochemistry and Molecular BiologyJohns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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25
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Fu R, Lu L, Jiang J, Nie M, Wang X, Lu Z. A case report of pedigree of a homozygous mutation of the steroidogenic acute regulatory protein causing lipoid congenital adrenal hyperplasia. Medicine (Baltimore) 2017; 96:e6994. [PMID: 28538409 PMCID: PMC5457889 DOI: 10.1097/md.0000000000006994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
RATIONALE Lipoid congenital adrenal hyperplasia (LCAH) is extremely rare, but is the most fatal form of congenital adrenal hyperplasia resulting from mutations in the steroidogenic acute regulatory protein (STAR) gene. LCAH arises from severe defects in the conversion of cholesterol to pregnenolone, the precursor of all steroids. PATIENT CONCERNS A case was reported that an 11-month-old Chinese girl who presented with a sex development disorder and hyponatremia. The clinical and genetic tests were carried out to confirm the diagnosis. The genogram of this case was also explored and analyzed. The girl presented with hyponatremia, decreased cortisol level, elevated adrenocorticotropic hormone level and female vulva despite a 46, XY karyotype. Enlarged adrenal glands and testicular-like tissue in the bilateral inguinal regions were detected with abdominal ultrasound. She was suspected of having LCAH, and definitive diagnosis was made after Sanger sequencing detected a homozygous frameshift variant c.707_708delins CTT (p.Lys236Thrfs*47) on exon 6 of the STAR gene. DIAGNOSES LCAH. INTERVENTIONS She was prescribed hydrocortisone 10 to 12 mg/m2 and 9a- fludrocortisone 100 mg/d. OUTCOMES Her skin hyperpigmentation and vomiting disappeared, and she had normal growth and development without adrenal crisis attacks. Her hormone and electrolyte levels remained normal, except for a persistently elevated ACTH level throughout 2 years of follow-up. At follow-up for 2 years, the patient is now 104.5 cm tall and weighs 23.3 kg at the age of 4 years old. Her plasma sodium and potassium concentration were normal. Her ACTH level is still elevated (1176 pg/mL). Her baseline sex hormone levels are testosterone <0.1 ng/dL and progesterone <0.08 ng/dL. The level of PRA (1.06 ng/mL per h) is within normal range. LESSONS This mutation was in accordance with previously reported gene mutations. The patient's parents were nonconsanguineous; her parents, paternal grandfather, and maternal grandmother were all found to be carriers of a STAR gene mutation. This 46 XY disorders of sex development case presented with adrenal insufficiency and female phenotype initially. The diagnosis was complicated depending on the clinical hormone workup. LCAH was confirmed by genetic tests and genogram of the family.
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MESH Headings
- Adrenal Hyperplasia, Congenital/diagnosis
- Adrenal Hyperplasia, Congenital/drug therapy
- Adrenal Hyperplasia, Congenital/genetics
- Diagnosis, Differential
- Disorder of Sex Development, 46,XY/diagnosis
- Disorder of Sex Development, 46,XY/drug therapy
- Disorder of Sex Development, 46,XY/genetics
- Female
- Frameshift Mutation
- Homozygote
- Humans
- Infant
- Pedigree
- Phosphoproteins/genetics
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Affiliation(s)
- Rong Fu
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Key Laboratory of Health and Family Planning Commission, Beijing, China
| | - Lin Lu
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Key Laboratory of Health and Family Planning Commission, Beijing, China
| | - Jun Jiang
- The Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Min Nie
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Key Laboratory of Health and Family Planning Commission, Beijing, China
| | - Xiaojing Wang
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Key Laboratory of Health and Family Planning Commission, Beijing, China
| | - Zhaolin Lu
- Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Key Laboratory of Health and Family Planning Commission, Beijing, China
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26
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Miller WL. Introduction to the 2016 Keith L. Parker Memorial Lecturer: Douglas M. Stocco, Ph.D. Mol Cell Endocrinol 2017; 441:2-6. [PMID: 27345241 DOI: 10.1016/j.mce.2016.06.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 11/16/2022]
Abstract
Douglas M. (Doug) Stocco is Professor Emeritus at Texas Tech University Health Sciences Center in Lubbock, TX, and is internationally renowned for his work characterizing the steroidogenic acute regulatory protein, StAR. Stocco's laboratory isolated and cloned StAR from mouse Leydig MA-10 cells, collaborated on the demonstration that StAR mutations cause congenital lipoid adrenal hyperplasia, and delineated much of what is known about the intracellular pathways that regulate its production. This work resolved a decades-long quest to identify the mechanism underlying the acute regulation of steroidogenesis.
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Affiliation(s)
- Walter L Miller
- Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA.
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27
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Lee J, Yamazaki T, Dong H, Jefcoate C. A single cell level measurement of StAR expression and activity in adrenal cells. Mol Cell Endocrinol 2017; 441:22-30. [PMID: 27521960 PMCID: PMC5896326 DOI: 10.1016/j.mce.2016.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 01/31/2023]
Abstract
The Steroidogenic acute regulatory protein (StAR) directs mitochondrial cholesterol uptake through a C-terminal cholesterol binding domain (CBD) and a 62 amino acid N-terminal regulatory domain (NTD) that contains an import sequence and conserved sites for inner membrane metalloproteases. Deletion of the NTD prevents mitochondrial import while maintaining steroidogenesis but with compromised cholesterol homeostasis. The rapid StAR-mediated cholesterol transfer in adrenal cells depends on concerted mRNA translation, p37 StAR phosphorylation and controlled NTD cleavage. The NTD controls this process with two cAMP-inducible modulators of, respectively, transcription and translation SIK1 and TIS11b/Znf36l1. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA resolves slow RNA splicing at the gene loci in cAMP-induced Y-1 cells and transfer of individual 3.5 kB mRNA molecules to mitochondria. StAR transcription depends on the CREB coactivator CRTC2 and PKA inhibition of the highly inducible suppressor kinase SIK1 and a basal counterpart SIK2. PKA-inducible TIS11b/Znf36l1 binds specifically to highly conserved elements in exon 7 thereby suppressing formation of mRNA and subsequent translation. Co-expression of SIK1, Znf36l1 with 3.5 kB StAR mRNA may limit responses to pulsatile signaling by ACTH while regulating the transition to more prolonged stress.
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Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Hui Dong
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United States
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States; Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States.
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Stocco DM, Zhao AH, Tu LN, Morohaku K, Selvaraj V. A brief history of the search for the protein(s) involved in the acute regulation of steroidogenesis. Mol Cell Endocrinol 2017; 441:7-16. [PMID: 27484452 PMCID: PMC5929480 DOI: 10.1016/j.mce.2016.07.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/26/2016] [Accepted: 07/26/2016] [Indexed: 12/14/2022]
Abstract
The synthesis of steroid hormones occurs in specific cells and tissues in the body in response to trophic hormones and other signals. In order to synthesize steroids de novo, cholesterol, the precursor of all steroid hormones, must be mobilized from cellular stores to the inner mitochondrial membrane (IMM) to be converted into the first steroid formed, pregnenolone. This delivery of cholesterol to the IMM is the rate-limiting step in this process, and has long been known to require the rapid synthesis of a new protein(s) in response to stimulation. Although several possibilities for this protein have arisen over the past few decades, most of the recent attention to fill this role has centered on the candidacies of the proteins the Translocator Protein (TSPO) and the Steroidogenic Acute Regulatory Protein (StAR). In this review, the process of regulating steroidogenesis is briefly described, the characteristics of the candidate proteins and the data supporting their candidacies summarized, and some recent findings that propose a serious challenge for the role of TSPO in this process are discussed.
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Affiliation(s)
- Douglas M Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Amy H Zhao
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Lan N Tu
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Kanako Morohaku
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
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29
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Tsai YY, Rainey WE, Bollag WB. Very low-density lipoprotein (VLDL)-induced signals mediating aldosterone production. J Endocrinol 2017; 232:R115-R129. [PMID: 27913572 PMCID: PMC8310676 DOI: 10.1530/joe-16-0237] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 01/14/2023]
Abstract
Aldosterone, secreted by the adrenal zona glomerulosa, enhances sodium retention, thus increasing blood volume and pressure. Excessive production of aldosterone results in high blood pressure and contributes to cardiovascular and renal disease, stroke and visual loss. Hypertension is also associated with obesity, which is correlated with other serious health risks as well. Although weight gain is associated with increased blood pressure, the mechanism by which excess fat deposits increase blood pressure remains unclear. Several studies have suggested that aldosterone levels are elevated with obesity and may represent a link between obesity and hypertension. In addition to hypertension, obese patients typically have dyslipidemia, including elevated serum levels of very low-density lipoprotein (VLDL). VLDL, which functions to transport triglycerides from the liver to peripheral tissues, has been demonstrated to stimulate aldosterone production. Recent studies suggest that the signaling pathways activated by VLDL are similar to those utilized by AngII. Thus, VLDL increases cytosolic calcium levels and stimulates phospholipase D (PLD) activity to result in the induction of steroidogenic acute regulatory (StAR) protein and aldosterone synthase (CYP11B2) expression. These effects seem to be mediated by the ability of VLDL to increase the phosphorylation (activation) of their regulatory transcription factors, such as the cAMP response element-binding (CREB) protein family of transcription factors. Thus, research into the pathways by which VLDL stimulates aldosterone production may identify novel targets for the development of therapies for the treatment of hypertension, particularly those associated with obesity, and other aldosterone-modulated pathologies.
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Affiliation(s)
- Ying-Ying Tsai
- Department of PhysiologyMedical College of Georgia at Augusta University (formerly Georgia Regents University), Augusta, Georgia, USA
| | - William E Rainey
- Departments of Molecular & Integrative Physiology and Internal MedicineUniversity of Michigan, Ann Arbor, Michigan, USA
| | - Wendy B Bollag
- Department of PhysiologyMedical College of Georgia at Augusta University (formerly Georgia Regents University), Augusta, Georgia, USA
- Charlie Norwood VA Medical CenterOne Freedom Way, Augusta, Georgia, USA
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30
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Miller WL. Disorders in the initial steps of steroid hormone synthesis. J Steroid Biochem Mol Biol 2017; 165:18-37. [PMID: 26960203 DOI: 10.1016/j.jsbmb.2016.03.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 12/29/2022]
Abstract
Steroidogenesis begins with cellular internalization of low-density lipoprotein particles and subsequent intracellular processing of cholesterol. Disorders in these steps include Adrenoleukodystrophy, Wolman Disease and its milder variant Cholesterol Ester Storage Disease, and Niemann-Pick Type C Disease, all of which may present with adrenal insufficiency. The means by which cholesterol is directed to steroidogenic mitochondria remains incompletely understood. Once cholesterol reaches the outer mitochondrial membrane, its delivery to the inner mitochondrial membrane is regulated by the steroidogenic acute regulatory protein (StAR). Severe StAR mutations cause classic congenital lipoid adrenal hyperplasia, characterized by lipid accumulation in the adrenal, adrenal insufficiency, and disordered sexual development in 46,XY individuals. The lipoid CAH phenotype, including spontaneous puberty in 46,XX females, is explained by a two-hit model. StAR mutations that retain partial function cause a milder, non-classic disease characterized by glucocorticoid deficiency, with lesser disorders of mineralocorticoid and sex steroid synthesis. Once inside the mitochondria, cholesterol is converted to pregnenolone by the cholesterol side-chain cleavage enzyme, P450scc, encoded by the CYP11A1 gene. Rare patients with mutations of P450scc are clinically and hormonally indistinguishable from those with lipoid CAH, and may also present as milder non-classic disease. Patients with P450scc defects do not have the massive adrenal hyperplasia that characterizes lipoid CAH, but adrenal imaging may occasionally fail to distinguish these, necessitating DNA sequencing.
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Affiliation(s)
- Walter L Miller
- Center for Reproductive Sciences, University of California, San Francisco, CA 94143-0556, United States.
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31
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Abstract
Adrenocorticotropin hormone (ACTH) produced by the anterior pituitary stimulates glucocorticoid synthesis by the adrenal cortex. The first step in glucocorticoid synthesis is the delivery of cholesterol to the mitochondrial matrix where the first enzymatic reaction in the steroid hormone biosynthetic pathway occurs. A key response of adrenal cells to ACTH is activation of the cAMP-protein kinase A (PKA) signaling pathway. PKA activation results in an acute increase in expression and function of the Steroidogenic Acute Regulatory protein (StAR). StAR plays an essential role in steroidogenesis- it controls the hormone-dependent movement of cholesterol across the mitochondrial membranes. Currently StAR's mechanism of action remains a major unanswered question in the field. However, some insight may be gained from understanding the mechanism(s) controlling the PKA-dependent phosphorylation of StAR at S194/195 (mouse/human StAR), a modification that is required for function. This mini-review provides a background on StAR's biology with a focus on StAR phosphorylation. The model for StAR translation and phosphorylation at the outer mitochondrial membrane, the location for StAR function, is presented to highlight a unifying theme emerging from diverse studies.
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Affiliation(s)
- Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville Louisville, KY, USA
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Khoury K, Barbar E, Ainmelk Y, Ouellet A, Lavigne P, LeHoux JG. Thirty-Eight-Year Follow-Up of Two Sibling Lipoid Congenital Adrenal Hyperplasia Patients Due to Homozygous Steroidogenic Acute Regulatory (STARD1) Protein Mutation. Molecular Structure and Modeling of the STARD1 L275P Mutation. Front Neurosci 2016; 10:527. [PMID: 27917104 PMCID: PMC5116571 DOI: 10.3389/fnins.2016.00527] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/31/2016] [Indexed: 11/13/2022] Open
Abstract
Objective: Review the impact of StAR (STARD1) mutations on steroidogenesis and fertility in LCAH patients. Examine the endocrine mechanisms underlying the pathology of the disorder and the appropriate therapy for promoting fertility and pregnancies. Design: Published data in the literature and a detailed 38-year follow-up of two sibling LCAH patients. Molecular structure and modeling of the STARD1 L275P mutation. Setting: University hospital. Patients: Patient A (46,XY female phenotype) and patient B (46,XX female) with LCAH bearing the L275P mutation in STARD1. Interventions: Since early-age diagnosis, both patients underwent corticoid replacement therapy. Patient A received estrogen therapy at pubertal age. Clomiphene therapy was given to Patient B to induce ovulation. Pregnancies were protected with progesterone administration. Main Outcome Measures: Clinical and molecular assessment of adrenal and gonadal functions. Results: Both patients have classic manifestations of corticosteroid deficiency observed in LCAH. Time of onset and severity were different. Patient A developed into a female phenotype due to early and severe damage of Leydig cells. Patient B started a progressive pubertal development, menarche and regular non-ovulatory cycle. She was able to have successful pregnancies. Conclusions: Understanding the molecular structure and function of STARD1 in all steroidogenic tissues is the key for comprehending the heterogeneous clinical manifestations of LCAH, and the development of an appropriate strategy for the induction of ovulation and protecting pregnancies in this disease.
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Affiliation(s)
- Khalil Khoury
- Department of Pediatrics, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Elie Barbar
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Youssef Ainmelk
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Annie Ouellet
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Pierre Lavigne
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
| | - Jean-Guy LeHoux
- Department of Biochemistry, Faculty of Medicine, University of Sherbrooke Sherbrooke, QC, Canada
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33
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Albarel F, Perrin J, Jegaden M, Roucher-Boulez F, Reynaud R, Brue T, Courbiere B. Successful IVF pregnancy despite inadequate ovarian steroidogenesis due to congenital lipoid adrenal hyperplasia (CLAH): a case report. Hum Reprod 2016; 31:2609-2612. [DOI: 10.1093/humrep/dew239] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 07/30/2016] [Accepted: 08/22/2016] [Indexed: 11/14/2022] Open
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34
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Zhang LH, Luo Z, Song YF, Shi X, Pan YX, Fan YF, Xu YH. Effects and mechanisms of waterborne copper exposure influencing ovary development and related hormones secretion in yellow catfish Pelteobagrus fulvidraco. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 178:88-98. [PMID: 27472784 DOI: 10.1016/j.aquatox.2016.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 07/21/2016] [Indexed: 06/06/2023]
Abstract
The present study was conducted to determine the effects and mechanism of waterborne copper (Cu) exposure influencing ovary development and related hormones secretion in yellow catfish Pelteobagrus fulvidraco. To this end, two experiments were conducted. In Exp. 1, the partial cDNA sequences of three steroidogenesis-related genes (androgen receptor (ar), steroidogenic factor 1 (sf-1) and steroidogenic acute regulatory protein (star)) were firstly characterized from P. fulvidraco. The predicted amino acid sequences for the P. fulvidraco ar, sf-1 and star contained the main structural features characteristic in other species. In Exp. 2, P. fulvidraco were exposed to three waterborne Cu concentrations (control, 30μg/l and 60μg/l, respectively) for 56days. Sampling occurred on day 28 and day 56, respectively. On day 28, the levels of serum sex-steroid hormones (FSH and LH) and the mRNA levels of steroidogenesis-related genes (3β-hsd, cyp11a1, cyp17, cyp19a, sf-1 and star) were significantly increased in ovary of P. fulvidraco exposed to 30μg Cu/l. The immunohistochemical analysis showed the positive reaction of ER, VTG and aromatase in low dose exposure group. These indicated that in low dose and relative short-term exposure, Cu was beneficial. In contrast, 60μg Cu/l exposure significantly reduced the levels of serum FSH, LH, E2 and P, and the mRNA levels of ovarian 20β-hsd, cyp19a and erα in P. fulvidraco. On day 56, waterborne Cu concentration exposure reduced the levels of serum gonadotropins and sex hormones, and down-regulated the mRNA levels of steroidogenesis-related genes, indicating long-term Cu exposure had toxic effect on the secretion of sex-steroid hormone in P. fulvidraco. For the first time, our study cloned cDNA sequences of ar, sf-1 and star in P. fulvidraco, and demonstrated the effects and mechanism of waterborne Cu exposure influencing hormones secretion and synthesis in dose- and time-dependent manner in P. fulvidraco, which will help to understand the Cu-induced reproductive toxicity at both protein and transcriptional levels in fish.
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Affiliation(s)
- Li-Han Zhang
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
| | - Zhi Luo
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China.
| | - Yu-Feng Song
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
| | - Xi Shi
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
| | - Ya-Xiong Pan
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
| | - Yao-Fang Fan
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
| | - Yi-Huan Xu
- Laboratory of Nutrition and Feed for Aquatic Economic Animals, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China
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Elustondo P, Martin LA, Karten B. Mitochondrial cholesterol import. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:90-101. [PMID: 27565112 DOI: 10.1016/j.bbalip.2016.08.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023]
Abstract
All animal subcellular membranes require cholesterol, which influences membrane fluidity and permeability, fission and fusion processes, and membrane protein function. The distribution of cholesterol among subcellular membranes is highly heterogeneous and the cholesterol content of each membrane must be carefully regulated. Compared to other subcellular membranes, mitochondrial membranes are cholesterol-poor, particularly the inner mitochondrial membrane (IMM). As a result, steroidogenesis can be controlled through the delivery of cholesterol to the IMM, where it is converted to pregnenolone. The low basal levels of cholesterol also make mitochondria sensitive to changes in cholesterol content, which can have a relatively large impact on the biophysical and functional characteristics of mitochondrial membranes. Increased mitochondrial cholesterol levels have been observed in diverse pathological conditions including cancer, steatohepatitis, Alzheimer disease and Niemann-Pick Type C1-deficiency, and are associated with increased oxidative stress, impaired oxidative phosphorylation, and changes in the susceptibility to apoptosis, among other alterations in mitochondrial function. Mitochondria are not included in the vesicular trafficking network; therefore, cholesterol transport to mitochondria is mostly achieved through the activity of lipid transfer proteins at membrane contact sites or by cytosolic, diffusible lipid transfer proteins. Here we will give an overview of the main mechanisms involved in mitochondrial cholesterol import, focusing on the steroidogenic acute regulatory protein StAR/STARD1 and other members of the StAR-related lipid transfer (START) domain protein family, and we will discuss how changes in mitochondrial cholesterol levels can arise and affect mitochondrial function. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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Affiliation(s)
- Pia Elustondo
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Laura A Martin
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Barbara Karten
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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36
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Tsai T, St John JC. The role of mitochondrial DNA copy number, variants, and haplotypes in farm animal developmental outcome. Domest Anim Endocrinol 2016; 56 Suppl:S133-46. [PMID: 27345311 DOI: 10.1016/j.domaniend.2016.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 03/11/2016] [Accepted: 03/15/2016] [Indexed: 01/20/2023]
Abstract
The vast majority of cellular energy is generated through the process of oxidative phosphorylation, which takes place in the electron transport chain in the mitochondria. The electron transport chain is encoded by 2 genomes, the chromosomal and the mitochondrial genomes. Mitochondrial DNA is associated with a number of traits, which include tolerance to heat, growth and physical performance, meat and milk quality, and fertility. Mitochondrial genomes can be clustered into groups known as mtDNA haplotypes. Mitochondrial DNA haplotypes are a potential genetic source for manipulating phenotypes in farm animals. The use of assisted reproductive technologies, such as nuclear transfer, allows favorable chromosomal genetic traits to be mixed and matched with sought after mtDNA haplotype traits. As a result super breeds can be generated.
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Affiliation(s)
- Tesha Tsai
- Centre for Genetic Diseases, Hudson Institute of Medical Research, Clayton, Vic, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Vic, 3168, Australia
| | - Justin C St John
- Centre for Genetic Diseases, Hudson Institute of Medical Research, Clayton, Vic, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, Vic, 3168, Australia.
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Huang Z, Ye J, Han L, Qiu W, Zhang H, Yu Y, Liang L, Gong Z, Gu X. Identification of five novel STAR variants in ten Chinese patients with congenital lipoid adrenal hyperplasia. Steroids 2016; 108:85-91. [PMID: 26827627 DOI: 10.1016/j.steroids.2016.01.016] [Citation(s) in RCA: 6] [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: 10/16/2015] [Revised: 01/01/2016] [Accepted: 01/26/2016] [Indexed: 10/22/2022]
Abstract
Congenital lipoid adrenal hyperplasia (CLAH) is a rare autosomal recessive disorder caused by defective synthesis of all steroids. This disorder is characterized by 46,XY sex reversal, skin hyperpigmentation, early-onset adrenal crisis and enlarged adrenal with fatty accumulation. CLAH is caused by mutations in the STAR gene. The clinical features and STAR gene mutation spectrum of a large cohort of Chinese patients with CLAH were not reported previously. We performed clinical retrospective review and genetic analysis of the STAR gene in ten unrelated Chinese phenotypic female patients who were clinically diagnosed with CLAH and followed up in our hospital from 2006 to 2015. All ten patients, including two 46,XY females and eight 46,XX females, presented skin hyperpigmentation and early salt-wasting episode, and showed normal growth and development after steroid replacement treatment. Totally 20 mutant alleles containing 11 different STAR gene mutations were identified in these ten patients, including five novel variants (two missense and three null variants), all predicted to be pathogenic in bioinformatics analysis, and six mutations described in previous literature. Among these 11 mutations, a reported mutation c.772C>T and a novel variant c.707_708delinsCTT were most frequent, accounting for 35% and 15% of the total mutant alleles, respectively. This is the first report of a large Chinese cohort with CLAH, presenting the mutation spectrum of the STAR gene and two possible founder mutations in the Chinese population, which may contribute to better genetic counseling and prenatal diagnosis.
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MESH Headings
- Adrenal Hyperplasia, Congenital/diagnosis
- Adrenal Hyperplasia, Congenital/genetics
- Adrenal Hyperplasia, Congenital/therapy
- Asian People/genetics
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Disorder of Sex Development, 46,XY/diagnosis
- Disorder of Sex Development, 46,XY/genetics
- Disorder of Sex Development, 46,XY/therapy
- Female
- Humans
- Infant
- Infant, Newborn
- Male
- Models, Molecular
- Mutation
- Mutation, Missense
- Protein Conformation
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Affiliation(s)
- Zhuo Huang
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Jun Ye
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Lianshu Han
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Wenjuan Qiu
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Huiwen Zhang
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Yongguo Yu
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Lili Liang
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Zhuwen Gong
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China
| | - Xuefan Gu
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute for Pediatric Research, Shanghai 200092, China.
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Lin Y, Hou X, Shen WJ, Hanssen R, Khor VK, Cortez Y, Roseman AN, Azhar S, Kraemer FB. SNARE-Mediated Cholesterol Movement to Mitochondria Supports Steroidogenesis in Rodent Cells. Mol Endocrinol 2016; 30:234-47. [PMID: 26771535 DOI: 10.1210/me.2015-1281] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Vesicular transport involving soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins is known to be responsible for many major cellular activities. In steroidogenic tissues, chronic hormone stimulation results in increased expression of proteins involved in the steroidogenic pathway, whereas acute hormone stimulation prompts the rapid transfer of cholesterol to the inner mitochondrial membrane to be utilized as substrate for steroid hormone production. Several different pathways are involved in supplying cholesterol to mitochondria, but mobilization of stored cholesteryl esters appears to initially constitute the preferred source; however, the mechanisms mediating this cholesterol transfer are not fully understood. To study the potential contribution of SNARE proteins in steroidogenesis, we examined the expression levels of various SNARE proteins in response to hormone stimulation in steroidogenic tissues and cells and established an in vitro mitochondria reconstitution assay system to assess the contribution of various SNARE proteins on cholesterol delivery for steroidogenesis. Our results from reconstitution experiments along with knockdown studies in rat primary granulosa cells and in a Leydig cell line show that soluble N-ethylmaleimide sensitive factor attachment protein-α, synaptosomal-associated protein of 25 kDa, syntaxin-5, and syntaxin-17 facilitate the transport of cholesterol to mitochondria. Thus, although StAR is required for efficient cholesterol movement into mitochondria for steroidogenesis, specific SNAREs participate and are necessary to mediate cholesterol movement to mitochondria.
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Affiliation(s)
- Ye Lin
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Xiaoming Hou
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Wen-Jun Shen
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Ruth Hanssen
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Victor K Khor
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Yuan Cortez
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Ann N Roseman
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Salman Azhar
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology, and Metabolism (Y.L., X.H., W.-J.S., R.H., V.K.K., S.A., F.B.K.), Stanford University, and Veterans Affairs Palo Alto Health Care System (Y.L., X.H., W.-J.S., R.H., V.K.K., Y.C., A.N.R., S.A., F.B.K.), Palo Alto, California 94304
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Paz C, Cornejo Maciel F, Gorostizaga A, Castillo AF, Mori Sequeiros García MM, Maloberti PM, Orlando UD, Mele PG, Poderoso C, Podesta EJ. Role of Protein Phosphorylation and Tyrosine Phosphatases in the Adrenal Regulation of Steroid Synthesis and Mitochondrial Function. Front Endocrinol (Lausanne) 2016; 7:60. [PMID: 27375556 PMCID: PMC4899475 DOI: 10.3389/fendo.2016.00060] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/25/2016] [Indexed: 12/17/2022] Open
Abstract
In adrenocortical cells, adrenocorticotropin (ACTH) promotes the activation of several protein kinases. The action of these kinases is linked to steroid production, mainly through steroidogenic acute regulatory protein (StAR), whose expression and activity are dependent on protein phosphorylation events at genomic and non-genomic levels. Hormone-dependent mitochondrial dynamics and cell proliferation are functions also associated with protein kinases. On the other hand, protein tyrosine dephosphorylation is an additional component of the ACTH signaling pathway, which involves the "classical" protein tyrosine phosphatases (PTPs), such as Src homology domain (SH) 2-containing PTP (SHP2c), and members of the MAP kinase phosphatase (MKP) family, such as MKP-1. PTPs are rapidly activated by posttranslational mechanisms and participate in hormone-stimulated steroid production. In this process, the SHP2 tyrosine phosphatase plays a crucial role in a mechanism that includes an acyl-CoA synthetase-4 (Acsl4), arachidonic acid (AA) release and StAR induction. In contrast, MKPs in steroidogenic cells have a role in the turn-off of the hormonal signal in ERK-dependent processes such as steroid synthesis and, perhaps, cell proliferation. This review analyzes the participation of these tyrosine phosphates in the ACTH signaling pathway and the action of kinases and phosphatases in the regulation of mitochondrial dynamics and steroid production. In addition, the participation of kinases and phosphatases in the signal cascade triggered by different stimuli in other steroidogenic tissues is also compared to adrenocortical cell/ACTH and discussed.
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Affiliation(s)
- Cristina Paz
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Fabiana Cornejo Maciel
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Alejandra Gorostizaga
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ana F. Castillo
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - M. Mercedes Mori Sequeiros García
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula M. Maloberti
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ulises D. Orlando
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Pablo G. Mele
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Cecilia Poderoso
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ernesto J. Podesta
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- *Correspondence: Ernesto J. Podesta, ,
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Ruggiero C, Lalli E. Impact of ACTH Signaling on Transcriptional Regulation of Steroidogenic Genes. Front Endocrinol (Lausanne) 2016; 7:24. [PMID: 27065945 PMCID: PMC4810002 DOI: 10.3389/fendo.2016.00024] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/14/2016] [Indexed: 01/12/2023] Open
Abstract
The trophic peptide hormone adrenocorticotropic (ACTH) stimulates steroid hormone biosynthesis evoking both a rapid, acute response and a long-term, chronic response, via the activation of cAMP/protein kinase A (PKA) signaling. The acute response is initiated by the mobilization of cholesterol from lipid stores and its delivery to the inner mitochondrial membrane, a process that is mediated by the steroidogenic acute regulatory protein. The chronic response results in the increased coordinated transcription of genes encoding steroidogenic enzymes. ACTH binding to its cognate receptor, melanocortin 2 receptor (MC2R), stimulates adenylyl cyclase, thus inducing cAMP production, PKA activation, and phosphorylation of specific nuclear factors, which bind to target promoters and facilitate coactivator protein recruitment to direct steroidogenic gene transcription. This review provides a general view of the transcriptional control exerted by the ACTH/cAMP system on the expression of genes encoding for steroidogenic enzymes in the adrenal cortex. Special emphasis will be given to the transcription factors required to mediate ACTH-dependent transcription of steroidogenic genes.
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Affiliation(s)
- Carmen Ruggiero
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275, Valbonne, France
- Laboratoire International Associé (LIA) CNRS NEOGENEX, Valbonne, France
- Université de Nice, Valbonne, France
- *Correspondence: Carmen Ruggiero, ; Enzo Lalli,
| | - Enzo Lalli
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275, Valbonne, France
- Laboratoire International Associé (LIA) CNRS NEOGENEX, Valbonne, France
- Université de Nice, Valbonne, France
- *Correspondence: Carmen Ruggiero, ; Enzo Lalli,
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El-Hayek S, Clarke HJ. Control of Oocyte Growth and Development by Intercellular Communication Within the Follicular Niche. Results Probl Cell Differ 2016; 58:191-224. [PMID: 27300180 DOI: 10.1007/978-3-319-31973-5_8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In the mammalian ovary, each oocyte grows and develops within its own structural and developmental niche-the follicle. Together with the female germ cell in the follicle are somatic granulosa cells, specialized companion cells that surround the oocyte and provide support to it, and an outer layer of thecal cells that serve crucial roles including steroid synthesis. These follicular compartments function as a single physiological unit whose purpose is to produce a healthy egg, which upon ovulation can be fertilized and give rise to a healthy embryo, thus enabling the female germ cell to fulfill its reproductive potential. Beginning from the initial stage of follicle formation and until terminal differentiation at ovulation, oocyte and follicle growth depend absolutely on cooperation between the different cellular compartments. This cooperation synchronizes the initiation of oocyte growth with follicle activation. During growth, it enables metabolic support for the follicle-enclosed oocyte and allows the follicle to fulfill its steroidogenic potential. Near the end of the growth period, intra-follicular interactions prevent the precocious meiotic resumption of the oocyte and ensure its nuclear differentiation. Finally, cooperation enables the events of ovulation, including meiotic maturation of the oocyte and expansion of the cumulus granulosa cells. In this chapter, we discuss the cellular interactions that enable the growing follicle to produce a healthy oocyte, focusing on the communication between the germ cell and the surrounding granulosa cells.
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Affiliation(s)
- Stephany El-Hayek
- Department of Obstetrics and Gynecology, McGill University, Montreal, QC, Canada
- Department of Biology, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Block E-M0.2218, Montreal, QC, Canada, H4A 3J1
| | - Hugh J Clarke
- Department of Obstetrics and Gynecology, McGill University, Montreal, QC, Canada.
- Department of Biology, McGill University, Montreal, QC, Canada.
- Research Institute of the McGill University Health Centre, 1001 Decarie Blvd, Block E-M0.2218, Montreal, QC, Canada, H4A 3J1.
- Department of Experimental Medicine, McGill University, Montreal, QC, Canada.
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Lee J, Tong T, Duan H, Foong YH, Musaitif I, Yamazaki T, Jefcoate C. Regulation of StAR by the N-terminal Domain and Coinduction of SIK1 and TIS11b/Znf36l1 in Single Cells. Front Endocrinol (Lausanne) 2016; 7:107. [PMID: 27531991 PMCID: PMC4969582 DOI: 10.3389/fendo.2016.00107] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/19/2016] [Indexed: 02/01/2023] Open
Abstract
The cholesterol transfer function of steroidogenic acute regulatory protein (StAR) is uniquely integrated into adrenal cells, with mRNA translation and protein kinase A (PKA) phosphorylation occurring at the mitochondrial outer membrane (OMM). The StAR C-terminal cholesterol-binding domain (CBD) initiates mitochondrial intermembrane contacts to rapidly direct cholesterol to Cyp11a1 in the inner membrane (IMM). The conserved StAR N-terminal regulatory domain (NTD) includes a leader sequence targeting the CBD to OMM complexes that initiate cholesterol transfer. Here, we show how the NTD functions to enhance CBD activity delivers more efficiently from StAR mRNA in adrenal cells, and then how two factors hormonally restrain this process. NTD processing at two conserved sequence sites is selectively affected by StAR PKA phosphorylation. The CBD functions as a receptor to stimulate the OMM/IMM contacts that mediate transfer. The NTD controls the transit time that integrates extramitochondrial StAR effects on cholesterol homeostasis with other mitochondrial functions, including ATP generation, inter-organelle fusion, and the major permeability transition pore in partnership with other OMM proteins. PKA also rapidly induces two additional StAR modulators: salt-inducible kinase 1 (SIK1) and Znf36l1/Tis11b. Induced SIK1 attenuates the activity of CRTC2, a key mediator of StAR transcription and splicing, but only as cAMP levels decline. TIS11b inhibits translation and directs the endonuclease-mediated removal of the 3.5-kb StAR mRNA. Removal of either of these functions individually enhances cAMP-mediated induction of StAR. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA reveals asymmetric transcription at the gene locus and slow RNA splicing that delays mRNA formation, potentially to synchronize with cholesterol import. Adrenal cells may retain slow transcription to integrate with intermembrane NTD activation. HR-FISH resolves individual 3.5-kb StAR mRNA molecules via dual hybridization at the 3'- and 5'-ends and reveals an unexpectedly high frequency of 1:1 pairing with mitochondria marked by the matrix StAR protein. This pairing may be central to translation-coupled cholesterol transfer. Altogether, our results show that adrenal cells exhibit high-efficiency StAR activity that needs to integrate rapid cholesterol transfer with homeostasis and pulsatile hormonal stimulation. StAR NBD, the extended 3.5-kb mRNA, SIK1, and Tis11b play important roles.
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Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
| | - Tiegang Tong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Haichuan Duan
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
| | - Yee Hoon Foong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Ibrahim Musaitif
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA
- *Correspondence: Colin Jefcoate,
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Midzak A, Papadopoulos V. Adrenal Mitochondria and Steroidogenesis: From Individual Proteins to Functional Protein Assemblies. Front Endocrinol (Lausanne) 2016; 7:106. [PMID: 27524977 PMCID: PMC4965458 DOI: 10.3389/fendo.2016.00106] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022] Open
Abstract
The adrenal cortex is critical for physiological function as the central site of glucocorticoid and mineralocorticoid synthesis. It possesses a great degree of specialized compartmentalization at multiple hierarchical levels, ranging from the tissue down to the molecular levels. In this paper, we discuss this functionalization, beginning with the tissue zonation of the adrenal cortex and how this impacts steroidogenic output. We then discuss the cellular biology of steroidogenesis, placing special emphasis on the mitochondria. Mitochondria are classically known as the "powerhouses of the cell" for their central role in respiratory adenosine triphosphate synthesis, and attention is given to mitochondrial electron transport, in both the context of mitochondrial respiration and mitochondrial steroid metabolism. Building on work demonstrating functional assembly of large protein complexes in respiration, we further review research demonstrating a role for multimeric protein complexes in mitochondrial cholesterol transport, steroidogenesis, and mitochondria-endoplasmic reticulum contact. We aim to highlight with this review the shift in steroidogenic cell biology from a focus on the actions of individual proteins in isolation to the actions of protein assemblies working together to execute cellular functions.
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Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University, Montreal, QC, Canada
- *Correspondence: Andrew Midzak, ; Vassilios Papadopoulos,
| | - Vassilios Papadopoulos
- Research Institute of the McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
- *Correspondence: Andrew Midzak, ; Vassilios Papadopoulos,
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Sluchanko NN, Tugaeva KV, Faletrov YV, Levitsky DI. High-yield soluble expression, purification and characterization of human steroidogenic acute regulatory protein (StAR) fused to a cleavable Maltose-Binding Protein (MBP). Protein Expr Purif 2015; 119:27-35. [PMID: 26555181 DOI: 10.1016/j.pep.2015.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/21/2015] [Accepted: 11/04/2015] [Indexed: 11/24/2022]
Abstract
Steroidogenic acute regulatory protein (StAR) is responsible for the rapid delivery of cholesterol to mitochondria where the lipid serves as a source for steroid hormones biosynthesis in adrenals and gonads. Despite many successful investigations, current understanding of the mechanism of StAR action is far from being completely clear. StAR was mostly obtained using denaturation/renaturation or in minor quantities in a soluble form at decreased temperatures that, presumably, limited the possibilities for its consequent detailed exploration. In our hands, existing StAR expression constructs could be bacterially expressed almost exclusively as insoluble forms, even upon decreased expression temperatures and in specific strains of Escherichia coli, and isolated protein tended to aggregate and was difficult to handle. To maximize the yield of soluble protein, optimized StAR sequence encompassing functional domain STARD1 (residues 66-285) was fused to the C-terminus of His-tagged Maltose-Binding Protein (MBP) with the possibility to cleave off the whole tag by 3C protease. The developed protocol of expression and purification comprising of a combination of subtractive immobilized metal affinity chromatography (IMAC) and size-exclusion chromatography allowed us to obtain up to 25 mg/1 L culture of completely soluble StAR protein, which was (i) homogenous according to SDS-PAGE, (ii) gave a single symmetrical peak on a gel-filtration, (iii) showed the characteristic CD spectrum and (iv) pH-dependent ability to bind a fluorescently-labeled cholesterol analogue. We conclude that our strategy provides fully soluble and native StAR protein which in future could be efficiently used for biotechnology and drug discovery aimed at modulation of steroids production.
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Affiliation(s)
- Nikolai N Sluchanko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia.
| | - Kristina V Tugaeva
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia; Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russia
| | - Yaroslav V Faletrov
- Research Institute for Physical Chemical Problems, Belarusian State University, Minsk, Belarus
| | - Dmitrii I Levitsky
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia; A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
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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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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: 43] [Impact Index Per Article: 4.8] [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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47
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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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48
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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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49
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Abstract
Aldosterone is a steroid hormone synthesized in and secreted from the outer layer of the adrenal cortex, the zona glomerulosa. Aldosterone is responsible for regulating sodium homeostasis, thereby helping to control blood volume and blood pressure. Insufficient aldosterone secretion can lead to hypotension and circulatory shock, particularly in infancy. On the other hand, excessive aldosterone levels, or those too high for sodium status, can cause hypertension and exacerbate the effects of high blood pressure on multiple organs, contributing to renal disease, stroke, visual loss, and congestive heart failure. Aldosterone is also thought to directly induce end-organ damage, including in the kidneys and heart. Because of the significance of aldosterone to the physiology and pathophysiology of the cardiovascular system, it is important to understand the regulation of its biosynthesis and secretion from the adrenal cortex. Herein, the mechanisms regulating aldosterone production in zona glomerulosa cells are discussed, with a particular emphasis on signaling pathways involved in the secretory response to the main controllers of aldosterone production, the renin-angiotensin II system, serum potassium levels and adrenocorticotrophic hormone. The signaling pathways involved include phospholipase C-mediated phosphoinositide hydrolysis, inositol 1,4,5-trisphosphate, cytosolic calcium levels, calcium influx pathways, calcium/calmodulin-dependent protein kinases, diacylglycerol, protein kinases C and D, 12-hydroxyeicostetraenoic acid, phospholipase D, mitogen-activated protein kinase pathways, tyrosine kinases, adenylate cyclase, and cAMP-dependent protein kinase. A complete understanding of the signaling events regulating aldosterone biosynthesis may allow the identification of novel targets for therapeutic interventions in hypertension, primary aldosteronism, congestive heart failure, renal disease, and other cardiovascular disorders.
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Affiliation(s)
- Wendy B Bollag
- Charlie Norwood VA Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia at Georgia Regents University, Augusta, Georgia
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50
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Prasad M, Kaur J, Pawlak KJ, Bose M, Whittal RM, Bose HS. Mitochondria-associated endoplasmic reticulum membrane (MAM) regulates steroidogenic activity via steroidogenic acute regulatory protein (StAR)-voltage-dependent anion channel 2 (VDAC2) interaction. J Biol Chem 2014; 290:2604-16. [PMID: 25505173 DOI: 10.1074/jbc.m114.605808] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Steroid hormones are essential for carbohydrate metabolism, stress management, and reproduction and are synthesized from cholesterol in mitochondria of adrenal glands and gonads/ovaries. In acute stress or hormonal stimulation, steroidogenic acute regulatory protein (StAR) transports substrate cholesterol into the mitochondria for steroidogenesis by an unknown mechanism. Here, we report for the first time that StAR interacts with voltage-dependent anion channel 2 (VDAC2) at the mitochondria-associated endoplasmic reticulum membrane (MAM) prior to its translocation to the mitochondrial matrix. In the MAM, StAR interacts with mitochondrial proteins Tom22 and VDAC2. However, Tom22 knockdown by siRNA had no effect on pregnenolone synthesis. In the absence of VDAC2, StAR was expressed but not processed into the mitochondria as a mature 30-kDa protein. VDAC2 interacted with StAR via its C-terminal 20 amino acids and N-terminal amino acids 221-229, regulating the mitochondrial processing of StAR into the mature protein. In the absence of VDAC2, StAR could not enter the mitochondria or interact with MAM-associated proteins, and therefore steroidogenesis was inhibited. Furthermore, the N terminus was not essential for StAR activity, and the N-terminal deletion mutant continued to interact with VDAC2. The endoplasmic reticulum-targeting prolactin signal sequence did not affect StAR association with the MAM and thus its mitochondrial targeting. Therefore, VDAC2 controls StAR processing and activity, and MAM is thus a central location for initiating mitochondrial steroidogenesis.
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Affiliation(s)
- Manoj Prasad
- From the Mercer University School of Medicine, Savannah, Georgia 31404
| | - Jasmeet Kaur
- From the Mercer University School of Medicine, Savannah, Georgia 31404
| | - Kevin J Pawlak
- From the Mercer University School of Medicine, Savannah, Georgia 31404
| | - Mahuya Bose
- Center of Excellence for Health Regeneration Biotechnology, Florida Biologix, University of Florida, Alachua, Florida 32615, Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida 32610
| | - Randy M Whittal
- Department of Chemistry, University of Alberta, Alberta T6G2G2, Canada, and
| | - Himangshu S Bose
- From the Mercer University School of Medicine, Savannah, Georgia 31404, Anderson Cancer Institute, Memorial University Medical Center, Savannah, Georgia 31404
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