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Mizutani M, Kuroda S, Oku M, Aoki W, Masuya T, Miyoshi H, Murai M. Identification of proteins involved in intracellular ubiquinone trafficking in Saccharomyces cerevisiae using artificial ubiquinone probe. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149147. [PMID: 38906315 DOI: 10.1016/j.bbabio.2024.149147] [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: 04/12/2024] [Revised: 05/28/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Ubiquinone (UQ) is an essential player in the respiratory electron transfer system. In Saccharomyces cerevisiae strains lacking the ability to synthesize UQ6, exogenously supplied UQs can be taken up and delivered to mitochondria through an unknown mechanism, restoring the growth of UQ6-deficient yeast in non-fermentable medium. Since elucidating the mechanism responsible may markedly contribute to therapeutic strategies for patients with UQ deficiency, many attempts have been made to identify the machinery involved in UQ trafficking in the yeast model. However, definite experimental evidence of the direct interaction of UQ with a specific protein(s) has not yet been demonstrated. To gain insight into intracellular UQ trafficking via a chemistry-based strategy, we synthesized a hydrophobic UQ probe (pUQ5), which has a photoreactive diazirine group attached to a five-unit isoprenyl chain and a terminal alkyne to visualize and/or capture the labeled proteins via click chemistry. pUQ5 successfully restored the growth of UQ6-deficient S. cerevisiae (Δcoq2) on a non-fermentable carbon source, indicating that this UQ was taken up and delivered to mitochondria, and served as a UQ substrate of respiratory enzymes. Through photoaffinity labeling of the mitochondria isolated from Δcoq2 yeast cells cultured in the presence of pUQ5, we identified many labeled proteins, including voltage-dependent anion channel 1 (VDAC1) and cytochrome c oxidase subunit 3 (Cox3). The physiological relevance of UQ binding to these proteins is discussed.
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Affiliation(s)
- Mirai Mizutani
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Seina Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masahide Oku
- Department of Bioscience and Biotechnology, Faculty of Bioenvironmental Sciences, Kyoto University of Advanced Science, Kameoka, Japan
| | - Wataru Aoki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
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2
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Shteinfer-Kuzmine A, Santhanam M, Shoshan-Barmatz V. VDAC1-Based Peptides as Potential Modulators of VDAC1 Interactions with Its Partners and as a Therapeutic for Cancer, NASH, and Diabetes. Biomolecules 2024; 14:1139. [PMID: 39334905 PMCID: PMC11430116 DOI: 10.3390/biom14091139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Revised: 09/03/2024] [Accepted: 09/06/2024] [Indexed: 09/30/2024] Open
Abstract
This review presents current knowledge related to the voltage-dependent anion channel-1 (VDAC1) as a multi-functional mitochondrial protein that acts in regulating both cell life and death. The location of VDAC1 at the outer mitochondrial membrane (OMM) allows control of metabolic cross-talk between the mitochondria and the rest of the cell, and also enables its interaction with proteins that are involved in metabolic, cell death, and survival pathways. VDAC1's interactions with over 150 proteins can mediate and regulate the integration of mitochondrial functions with cellular activities. To target these protein-protein interactions, VDAC1-derived peptides have been developed. This review focuses specifically on cell-penetrating VDAC1-based peptides that were developed and used as a "decoy" to compete with VDAC1 for its VDAC1-interacting proteins. These peptides interfere with VDAC1 interactions, for example, with metabolism-associated proteins such as hexokinase (HK), or with anti-apoptotic proteins such as Bcl-2 and Bcl-xL. These and other VDAC1-interacting proteins are highly expressed in many cancers. The VDAC1-based peptides in cells in culture selectively affect cancerous, but not non-cancerous cells, inducing cell death in a variety of cancers, regardless of the cancer origin or genetics. They inhibit cell energy production, eliminate cancer stem cells, and act very rapidly and at low micro-molar concentrations. The activity of these peptides has been validated in several mouse cancer models of glioblastoma, lung, and breast cancers. Their anti-cancer activity involves a multi-pronged attack targeting the hallmarks of cancer. They were also found to be effective in treating non-alcoholic fatty liver disease and diabetes mellitus. Thus, VDAC1-based peptides, by targeting VDAC1-interacting proteins, offer an affordable and innovative new conceptual therapeutic paradigm that can potentially overcome heterogeneity, chemoresistance, and invasive metastatic formation.
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Affiliation(s)
- Anna Shteinfer-Kuzmine
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Manikandan Santhanam
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
| | - Varda Shoshan-Barmatz
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel;
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3
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Bose HS. Dry molten globule conformational state of CYP11A1 (SCC) regulates the first step of steroidogenesis in the mitochondrial matrix. iScience 2024; 27:110039. [PMID: 38868187 PMCID: PMC11167429 DOI: 10.1016/j.isci.2024.110039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/18/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024] Open
Abstract
Multiple metabolic events occur in mitochondria. Mitochondrial protein translocation from the cytoplasm across compartments depends on the amino acid sequence within the precursor. At the mitochondria associated-ER membrane, misfolding of a mitochondrial targeted protein prior to import ablates metabolism. CYP11A1, cytochrome P450 cholesterol side chain cleavage enzyme (SCC), is imported from the cytoplasm to mitochondrial matrix catalyzing cholesterol to pregnenolone, an essential step for metabolic processes and mammalian survival. Multiple steps regulate the availability of an actively folded SCC; however, the mechanism is unknown. We identified that a dry molten globule state of SCC exists in the matrix by capturing intermediate protein folding steps dictated by its C-terminus. The intermediate dry molten globule state in the mitochondrial matrix of living cells is stable with a limited network of interaction and is inactive. The dry molten globule is activated with hydrogen ions availability, triggering cleavage of cholesterol sidechain, and initiating steroidogenesis.
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Affiliation(s)
- Himangshu S. Bose
- Laboratory of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
- Anderson Cancer Institute, Memorial University Medical Center, Savannah, GA 31404, USA
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4
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Witt A, Mateska I, Palladini A, Sinha A, Wölk M, Harauma A, Bechmann N, Pamporaki C, Dahl A, Rothe M, Kopaliani I, Adolf C, Riester A, Wielockx B, Bornstein SR, Kroiss M, Peitzsch M, Moriguchi T, Fedorova M, Grzybek M, Chavakis T, Mirtschink P, Alexaki VI. Fatty acid desaturase 2 determines the lipidomic landscape and steroidogenic function of the adrenal gland. SCIENCE ADVANCES 2023; 9:eadf6710. [PMID: 37478183 PMCID: PMC10361602 DOI: 10.1126/sciadv.adf6710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 06/16/2023] [Indexed: 07/23/2023]
Abstract
Corticosteroids regulate vital processes, including stress responses, systemic metabolism, and blood pressure. Here, we show that corticosteroid synthesis is related to the polyunsaturated fatty acid (PUFA) content of mitochondrial phospholipids in adrenocortical cells. Inhibition of the rate-limiting enzyme of PUFA synthesis, fatty acid desaturase 2 (FADS2), leads to perturbations in the mitochondrial lipidome and diminishes steroidogenesis. Consistently, the adrenocortical mitochondria of Fads2-/- mice fed a diet with low PUFA concentration are structurally impaired and corticoid levels are decreased. On the contrary, FADS2 expression is elevated in the adrenal cortex of obese mice, and plasma corticosterone is increased, which can be counteracted by dietary supplementation with the FADS2 inhibitor SC-26192 or icosapent ethyl, an eicosapentaenoic acid ethyl ester. In humans, FADS2 expression is elevated in aldosterone-producing adenomas compared to non-active adenomas or nontumorous adrenocortical tissue and correlates with expression of steroidogenic genes. Our data demonstrate that FADS2-mediated PUFA synthesis determines adrenocortical steroidogenesis in health and disease.
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Affiliation(s)
- Anke Witt
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
- Department of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
| | - Ivona Mateska
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Alessandra Palladini
- Center of Membrane Biochemistry and Lipid Research, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Centre Munich at the University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, 85764, Germany
| | - Anupam Sinha
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Michele Wölk
- Center of Membrane Biochemistry and Lipid Research, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
| | - Akiko Harauma
- School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa, 252-5201, Japan
| | - Nicole Bechmann
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Christina Pamporaki
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Andreas Dahl
- DRESDEN-Concept Genome Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, 01307, Germany
| | | | - Irakli Kopaliani
- Department of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
| | - Christian Adolf
- Department of Internal Medicine IV, University Hospital Munich, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Anna Riester
- Department of Internal Medicine IV, University Hospital Munich, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
| | - Ben Wielockx
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Stefan R. Bornstein
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Matthias Kroiss
- Department of Internal Medicine IV, University Hospital Munich, Ludwig-Maximilians-Universität München, Munich, 80336, Germany
- Department of Internal Medicine I, Division of Endocrinology and Diabetes, University Hospital, University of Wuerzburg, Wuerzburg, 97080, Germany
| | - Mirko Peitzsch
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Toru Moriguchi
- School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa, 252-5201, Japan
| | - Maria Fedorova
- Center of Membrane Biochemistry and Lipid Research, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
| | - Michal Grzybek
- Center of Membrane Biochemistry and Lipid Research, Faculty of Medicine, Technische Universität Dresden, Dresden, 01307, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Centre Munich at the University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, 85764, Germany
| | - Triantafyllos Chavakis
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
- Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Peter Mirtschink
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
| | - Vasileia Ismini Alexaki
- Institute for Clinical Chemistry and Laboratory Medicine, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, 01307, Germany
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5
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Melchinger P, Garcia BM. Mitochondria are midfield players in steroid synthesis. Int J Biochem Cell Biol 2023; 160:106431. [PMID: 37207805 DOI: 10.1016/j.biocel.2023.106431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/21/2023]
Abstract
Steroids are important membrane components and signaling metabolites and thus are required for cellular homeostasis. All mammalian cells retain the ability to uptake and synthesize steroids. Dysregulation of steroid levels leads to profound effects on cellular function and organismal health. Hence it comes as no surprise that steroid synthesis is tightly regulated. It is well established that the main site for steroid synthesis and regulation is the endoplasmic reticulum. However, mitochondria are essential for: (1) cholesterol production (the precursor of all steroids) by exporting citrate and; (2) the products of steroidogenesis (such as mineralocorticoids and glucocorticoids). In this review, we describe the midfield player role of mitochondria in steroid synthesis and bring the idea of mitochondria actively participating in steroid synthesis regulation. A better understanding of the mitochondrial regulatory roles in steroid synthesis would open new avenues to targeted approaches aiming to control steroid levels.
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Affiliation(s)
- Philipp Melchinger
- Max Planck Institute for Biology of Ageing, Cologne, Germany; Department of Biological Sciences, University of Cologne, Cologne, Germany.
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6
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Martinez–Arguelles DB, Nedow JW, Gukasyan HJ, Papadopoulos V. Oral administration of VDAC1-derived small molecule peptides increases circulating testosterone levels in male rats. Front Endocrinol (Lausanne) 2023; 13:1003017. [PMID: 36686419 PMCID: PMC9846164 DOI: 10.3389/fendo.2022.1003017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/13/2022] [Indexed: 01/05/2023] Open
Abstract
Cholesterol is the precursor of all steroid hormones, and the entry of cholesterol into the mitochondria is the rate-limiting step of steroidogenesis. Voltage-dependent anion channel (VDAC1) is an outer mitochondrial protein part of a multiprotein complex that imports cholesterol. We previously reported that intratesticular administration of a 25 amino acid peptide blocking the interaction between 14-3-3ϵ with VDAC1 increased circulating levels of testosterone. This fusion peptide was composed of a HIV-1 transactivator of transcription (TAT) protein transduction domain cell-penetrating peptide, a glycine linker, and amino acids 159-172 of VDAC1 (TV159-172). Here, we describe the development of a family of small molecules that increase circulating testosterone levels after an oral administration. We first characterized an animal model where TV159-172 was delivered subcutaneously. This subcutaneous model allowed us to study the interactions between TV159-172 and the hypothalamus-pituitary-gonadal axis (HPG) and identify the biologically active core of TV159-172. The core consisted of the tetrapeptide RVTQ, which we used as a platform to design synthetic peptide derivatives that can be administered orally. We developed a second animal model to test various derivatives of RVTQ and found 11 active compounds. Dose-response experiments identified 4 synthetic peptides that robustly increased androgen levels in a specific manner. We selected RdVTQ as the leading VDAC1-core derivative and profiled the response across the lifespan of Brown-Norway rats. In summary, we present the development of a new class of therapeutics that act within the HPG axis to increase testosterone levels specifically. This new class of small molecules self-regulates, preventing abuse.
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Affiliation(s)
- Daniel B. Martinez–Arguelles
- Department of Medicine, Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada
| | - Jennifer W. Nedow
- Department of Medicine, Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada
| | - Hovhannes J. Gukasyan
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, United States
| | - Vassilios Papadopoulos
- Department of Medicine, Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, United States
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7
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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: 12] [Impact Index Per Article: 6.0] [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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8
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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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9
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Regulation of Estradiol Synthesis by Aromatase Interacting Partner in Breast (AIPB). Mol Cell Biol 2021; 41:e0035721. [PMID: 34460330 DOI: 10.1128/mcb.00357-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Estradiol is essential for the development of female sex characteristics and fertility. Postmenopausal women and breast cancer patients have high levels of estradiol. Aromatase catalyzes estradiol synthesis; however, the factors regulating aromatase activity are unknown. We identified a new 22-kDa protein, aromatase interacting partner in breast (AIPB), from the endoplasmic reticulum of human breast tissue. AIPB expression is reduced in tumorigenic breast and further reduced in triple-negative tumors. Like that of aromatase, AIPB expression is induced by nonsteroidal estrogen. We found that AIPB and aromatase interact in nontumorigenic and tumorigenic breast tissues and cells. In tumorigenic cells, conditional AIPB overexpression decreased estradiol, and blocking AIPB availability with an AIPB-binding antibody increased estradiol. Estradiol synthesis is highly increased in AIPB knockdown cells, suggesting that the newly identified AIPB protein is important for aromatase activity and a key modulator of estradiol synthesis. Thus, a change in AIPB protein expression may represent an early event in tumorigenesis and be predictive of an increased risk of developing breast cancer.
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10
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Khan A, Kuriachan G, Mahalakshmi R. Cellular Interactome of Mitochondrial Voltage-Dependent Anion Channels: Oligomerization and Channel (Mis)Regulation. ACS Chem Neurosci 2021; 12:3497-3515. [PMID: 34503333 DOI: 10.1021/acschemneuro.1c00429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Voltage-dependent anion channels (VDACs) of the outer mitochondrial membrane are known conventionally as metabolite flux proteins. However, research findings in the past decade have revealed the multifaceted regulatory roles of VDACs, from governing cellular physiology and mitochondria-mediated apoptosis to directly regulating debilitating cancers and neurodegenerative diseases. VDACs achieve these diverse functions by establishing isoform-dependent stereospecific interactomes in the cell with the cytosolic constituents and endoplasmic reticulum complexes, and the machinery of the mitochondrial compartments. VDACs are now increasingly recognized as regulatory hubs of the cell. Not surprisingly, even the transient misregulation of VDACs results directly in mitochondrial dysfunction. Additionally, human VDACs are now implicated in interaction with aggregation-prone cytosolic proteins, including Aβ, tau, and α-synuclein, contributing directly to the onset of Alzheimer's and Parkinson's diseases. Deducing the interaction dynamics and mechanisms can lead to VDAC-targeted peptide-based therapeutics that can alleviate neurodegenerative states. This review succinctly presents the latest findings of the VDAC interactome, and the mode(s) of VDAC-dependent regulation of biochemical physiology. We also discuss the relevance of VDACs in pathophysiological states and aggregation-associated diseases and address how VDACs will facilitate the development of next-generation precision medicines.
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Affiliation(s)
- Altmash Khan
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Gifty Kuriachan
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India
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11
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Hiser C, Montgomery BL, Ferguson-Miller S. TSPO protein binding partners in bacteria, animals, and plants. J Bioenerg Biomembr 2021; 53:463-487. [PMID: 34191248 PMCID: PMC8243069 DOI: 10.1007/s10863-021-09905-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/12/2021] [Indexed: 12/11/2022]
Abstract
The ancient membrane protein TSPO is phylogenetically widespread from archaea and bacteria to insects, vertebrates, plants, and fungi. TSPO’s primary amino acid sequence is only modestly conserved between diverse species, although its five transmembrane helical structure appears mainly conserved. Its cellular location and orientation in membranes have been reported to vary between species and tissues, with implications for potential diverse binding partners and function. Most TSPO functions relate to stress-induced changes in metabolism, but in many cases it is unclear how TSPO itself functions—whether as a receptor, a sensor, a transporter, or a translocator. Much evidence suggests that TSPO acts indirectly by association with various protein binding partners or with endogenous or exogenous ligands. In this review, we focus on proteins that have most commonly been invoked as TSPO binding partners. We suggest that TSPO was originally a bacterial receptor/stress sensor associated with porphyrin binding as its most ancestral function and that it later developed additional stress-related roles in eukaryotes as its ability to bind new partners evolved.
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Affiliation(s)
- Carrie Hiser
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
| | - Beronda L Montgomery
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
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12
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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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13
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Bose HS, Whittal RM, Marshall B, Rajapaksha M, Wang NP, Bose M, Perry EW, Zhao ZQ, Miller WL. A Novel Mitochondrial Complex of Aldosterone Synthase, Steroidogenic Acute Regulatory Protein, and Tom22 Synthesizes Aldosterone in the Rat Heart. J Pharmacol Exp Ther 2021; 377:108-120. [PMID: 33526603 DOI: 10.1124/jpet.120.000365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Aldosterone, which regulates renal salt retention, is synthesized in adrenocortical mitochondria in response to angiotensin II. Excess aldosterone causes myocardial injury and heart failure, but potential intracardiac aldosterone synthesis has been controversial. We hypothesized that the stressed heart might produce aldosterone. We used blue native gel electrophoresis, immunoblotting, protein crosslinking, coimmunoprecipitations, and mass spectrometry to assess rat cardiac aldosterone synthesis. Chronic infusion of angiotensin II increased circulating corticosterone levels 350-fold and induced cardiac fibrosis. Angiotensin II doubled and telmisartan inhibited aldosterone synthesis by heart mitochondria and cardiac production of aldosterone synthase (P450c11AS). Heart aldosterone synthesis required P450c11AS, Tom22 (a mitochondrial translocase receptor), and the intramitochondrial form of the steroidogenic acute regulatory protein (StAR); protein crosslinking and coimmunoprecipitation studies showed that these three proteins form a 110-kDa complex. In steroidogenic cells, extramitochondrial (37-kDa) StAR promotes cholesterol movement from the outer to inner mitochondrial membrane where cholesterol side-chain cleavage enzyme (P450scc) converts cholesterol to pregnenolone, thus initiating steroidogenesis, but no function has previously been ascribed to intramitochondrial (30-kDa) StAR; our data indicate that intramitochondrial 30-kDa StAR is required for aldosterone synthesis in the heart, forming a trimolecular complex with Tom22 and P450c11AS. This is the first activity ascribed to intramitochondrial StAR, but how this promotes P450c11AS activity is unclear. The stressed heart did not express P450scc, suggesting that circulating corticosterone (rather than intracellular cholesterol) is the substrate for cardiac aldosterone synthesis. Thus, the stressed heart produced aldosterone using a previously undescribed intramitochondrial mechanism that involves P450c11AS, Tom22, and 30-kDa StAR. SIGNIFICANCE STATEMENT: Prior studies of potential cardiac aldosterone synthesis have been inconsistent. This study shows that the stressed rat heart produces aldosterone by a novel mechanism involving aldosterone synthase, Tom22, and intramitochondrial steroidogenic acute regulatory protein (StAR) apparently using circulating corticosterone as substrate. This study establishes that the stressed rat heart produces aldosterone and for the first time identifies a biological role for intramitochondrial 30-kDa StAR.
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Affiliation(s)
- Himangshu S Bose
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Randy M Whittal
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Brendan Marshall
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Maheshinie Rajapaksha
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Ning Ping Wang
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Madhuchanda Bose
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Elizabeth W Perry
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Zhi-Qing Zhao
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
| | - Walter L Miller
- Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia (H.S.B., M.R., N.P.W., Z.-Q.Z.); Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada (R.M.W.); Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Georgia (B.M., E.W.P.); Curtiss Healthcare, University of Florida Innovate Sid Martin Biotechbology Incubator, Gainesville, Florida (M.B.); Anderson Cancer Institute, Savannah, Georgia (H.S.B.); and Department of Pediatrics and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (W.L.M.)
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14
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Yang S, Zhou R, Zhang C, He S, Su Z. Mitochondria-Associated Endoplasmic Reticulum Membranes in the Pathogenesis of Type 2 Diabetes Mellitus. Front Cell Dev Biol 2020; 8:571554. [PMID: 33195204 PMCID: PMC7606698 DOI: 10.3389/fcell.2020.571554] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/21/2020] [Indexed: 02/05/2023] Open
Abstract
The endoplasmic reticulum (ER) and mitochondria are essential intracellular organelles that actively communicate via temporally and spatially formed contacts called mitochondria-associated membranes (MAMs). These mitochondria-ER contacts are not only necessary for the physiological function of the organelles and their coordination with each other, but they also control the intracellular lipid exchange, calcium signaling, cell survival, and homeostasis in cellular metabolism. Growing evidence strongly supports the role of the mitochondria-ER connection in the insulin resistance of peripheral tissues, pancreatic β cell dysfunction, and the consequent development of type 2 diabetes mellitus (T2DM). In this review, we summarize current advances in the understanding of the mitochondria-ER connection and specifically focus on addressing a new perspective of the alterations in mitochondria-ER communication in insulin signaling and β cell maintenance.
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Affiliation(s)
- Shanshan Yang
- Molecular Medicine Research Center and National Clinical Research Center for Geriatrics, West China Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Ruixue Zhou
- Molecular Medicine Research Center and National Clinical Research Center for Geriatrics, West China Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Caixia Zhang
- Molecular Medicine Research Center and National Clinical Research Center for Geriatrics, West China Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Siyuan He
- Molecular Medicine Research Center and National Clinical Research Center for Geriatrics, West China Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Zhiguang Su
- Molecular Medicine Research Center and National Clinical Research Center for Geriatrics, West China Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
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15
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Gliozzi M, Musolino V, Bosco F, Scicchitano M, Scarano F, Nucera S, Zito MC, Ruga S, Carresi C, Macrì R, Guarnieri L, Maiuolo J, Tavernese A, Coppoletta AR, Nicita C, Mollace R, Palma E, Muscoli C, Belzung C, Mollace V. Cholesterol homeostasis: Researching a dialogue between the brain and peripheral tissues. Pharmacol Res 2020; 163:105215. [PMID: 33007421 DOI: 10.1016/j.phrs.2020.105215] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023]
Abstract
Cholesterol homeostasis is a highly regulated process in human body because of its several functions underlying the biology of cell membranes, the synthesis of all steroid hormones and bile acids and the need of trafficking lipids destined to cell metabolism. In particular, it has been recognized that peripheral and central nervous system cholesterol metabolism are separated by the blood brain barrier and are regulated independently; indeed, peripherally, it depends on the balance between dietary intake and hepatic synthesis on one hand and its degradation on the other, whereas in central nervous system it is synthetized de novo to ensure brain physiology. In view of this complex metabolism and its relevant functions in mammalian, impaired levels of cholesterol can induce severe cellular dysfunction leading to metabolic, cardiovascular and neurodegenerative diseases. The aim of this review is to clarify the role of cholesterol homeostasis in health and disease highlighting new intriguing aspects of the cross talk between its central and peripheral metabolism.
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Affiliation(s)
- Micaela Gliozzi
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Vincenzo Musolino
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Francesca Bosco
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Miriam Scicchitano
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Federica Scarano
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Saverio Nucera
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Maria Caterina Zito
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Stefano Ruga
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Cristina Carresi
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Roberta Macrì
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Lorenza Guarnieri
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Jessica Maiuolo
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Annamaria Tavernese
- Division of Cardiology, University Hospital Policlinico Tor Vergata, Rome, Italy.
| | - Anna Rita Coppoletta
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Caterina Nicita
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Rocco Mollace
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Ernesto Palma
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy.
| | - Carolina Muscoli
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy; IRCCS San Raffaele Pisana, Via di Valcannuta, Rome, Italy.
| | | | - Vincenzo Mollace
- Institute of Research for Food Safety & Health (IRC-FSH) - Department of Health Sciences, University "Magna Graecia" of Catanzaro, Catanzaro, Italy; IRCCS San Raffaele Pisana, Via di Valcannuta, Rome, Italy.
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16
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Bose HS, Marshall B, Debnath DK, Perry EW, Whittal RM. Electron Transport Chain Complex II Regulates Steroid Metabolism. iScience 2020; 23:101295. [PMID: 32623340 PMCID: PMC7334606 DOI: 10.1016/j.isci.2020.101295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/23/2020] [Accepted: 06/15/2020] [Indexed: 11/15/2022] Open
Abstract
The first steroidogenic enzyme, cytochrome P450-side-chain-cleavage (SCC), requires electron transport chain (ETC) complexes III and IV to initiate steroid metabolic processes for mammalian survival. ETC complex II, containing succinate dehydrogenase (quinone), acts with the TCA cycle and has no proton pumping capacity. We show that complex II is required for SCC activation through the proton pump, generating an intermediate state for addition of phosphate by succinate. Phosphate anions in the presence of succinate form a stable mitochondrial complex with higher enthalpy (-ΔH) and enhanced activity. Inhibition of succinate action prevents SCC processing at the intermediate state and ablates activity and mitochondrial protein network. This is the first report directly showing that a protein intermediate state is activated by succinate, facilitating the ETC complex II to interact with complexes III and IV for continued mitochondrial metabolic process, suggesting complex II is essential for steroid metabolism regulation. P450 SCC synthesizes first steroid with the electrons from ETC complex III to IV Succinate from complex II activates complex III for the metabolic activity Absence of succinate ablates mitochondrial processing of SCC and metabolic activity Succinate anion stabilizes ETC complex II for the activation of steroid metabolism
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Affiliation(s)
- Himangshu S Bose
- Biomedical Sciences, Mercer U School of Medicine, Memorial University Medical Center, 1250 East 66th Street, Savannah, GA 31404, USA; Anderson Cancer Institute, Savannah, GA, USA.
| | - Brendan Marshall
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Dilip K Debnath
- Biomedical Sciences, Mercer U School of Medicine, Memorial University Medical Center, 1250 East 66th Street, Savannah, GA 31404, USA
| | - Elizabeth W Perry
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Randy M Whittal
- Department of Chemistry, University of Alberta, Edmonton, Canada
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17
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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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18
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Xie Y, Jiang H, Chang J, Wang Y, Li J, Wang H. Gonadal disruption after single dose exposure of prothioconazole and prothioconazole-desthio in male lizards (Eremias argus). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113297. [PMID: 31610514 DOI: 10.1016/j.envpol.2019.113297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/30/2019] [Accepted: 09/20/2019] [Indexed: 06/10/2023]
Abstract
Prothioconazole (PTC) is a widely used triazole fungicide with low toxicity, and its desulfurization metabolite, prothioconazole-desthio (PTC-d), is reported to have higher reproductive toxicity to mammals. However, little is known about the reproductive toxicity, much less endocrine disrupting effect, of these two chemicals on reptiles. In this study, we investigated the effects of single dose of PTC/PTC-d (100 mg kg-1 body weight) exposure on the pathomorphism of testes and epididymides, serum sex steroid hormones (testosterone and 17β-estradiol) and transcription of steroidogenic-related genes (STARD, cyp11A, cyp17, cyp19A, 17β-HSD, 3β-HSD, AR and ER-α) in gonads of male lizards (Eremias argus). Although structural disorder existed in PTC-d exposure group, severe gonadal disruption, especially suppression of spermatogenesis was only observed in testis after PTC treatment, which consequently led to the lack of spermatozoa in epididymal ducts. Consistent with this result, T/E2 value in PTC exposure was elevated to a significant higher level compared with control and continually increased over time, while T/E2 value in the PTC-d exposure group slightly increased only at 12 h. These results demonstrated a more serious disruption of PTC on male lizard gonads than PTC-d. In addition, the expression of cyp17 gene was inhibited at 6 h, however, was induced at 12 h, and exhibited negative correlations with STARD, cyp11A and 3β-HSD after PTC exposure at each timepoint. In PTC-d group, the expression of STARD and 3β-HSD were significantly down-regulated, in contrast, cyp11A and cyp17 were up-regulated, and each gene showed consistent changes over time. For 17β-HSD, no significance was observed in both treated groups. This study was the first to compare the gonadal disruption of PTC and PTC-d in male lizards and elucidated that these two chemicals influenced the physiological function of male gonads through differential transcriptional modulation.
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Affiliation(s)
- Yun Xie
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19A, Beijing, 100049, China
| | - Haotian Jiang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19A, Beijing, 100049, China
| | - Jing Chang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China
| | - Yinghuan Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China
| | - Jianzhong Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China
| | - Huili Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing, 100085, China.
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19
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Abobaker H, Hu Y, Omer NA, Hou Z, Idriss AA, Zhao R. Maternal betaine suppresses adrenal expression of cholesterol trafficking genes and decreases plasma corticosterone concentration in offspring pullets. J Anim Sci Biotechnol 2019; 10:87. [PMID: 31827786 PMCID: PMC6862747 DOI: 10.1186/s40104-019-0396-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/21/2019] [Indexed: 11/30/2022] Open
Abstract
Background Laying hens supplemented with betaine demonstrate activated adrenal steroidogenesis and deposit higher corticosterone (CORT) in the egg yolk. Here we further investigate the effect of maternal betaine on the plasma CORT concentration and adrenal expression of steroidogenic genes in offspring pullets. Results Maternal betaine significantly reduced (P < 0.05) plasma CORT concentration and the adrenal expression of vimentin that is involved in trafficking cholesterol to the mitochondria for utilization in offspring pullets. Concurrently, voltage-dependent anion channel 1 and steroidogenic acute regulatory protein, the two mitochondrial proteins involved in cholesterol influx, were both down-regulated at mRNA and protein levels. However, enzymes responsible for steroid syntheses, such as cytochrome P450 family 11 subfamily A member 1 and cytochrome P450 family 21 subfamily A member 2, were significantly (P < 0.05) up-regulated at mRNA or protein levels in the adrenal gland of pullets derived from betaine-supplemented hens. Furthermore, expression of transcription factors, such as steroidogenic factor-1, sterol regulatory element-binding protein 1 and cAMP response element-binding protein, was significantly (P < 0.05) enhanced, together with their downstream target genes, such as 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, LDL receptor and sterol regulatory element-binding protein cleavage-activating protein. The promoter regions of most steroidogenic genes were significantly (P < 0.05) hypomethylated, although methyl transfer enzymes, such as AHCYL, GNMT1 and BHMT were up-regulated. Conclusions These results indicate that the reduced plasma CORT in betaine-supplemented offspring pullets is linked to suppressed cholesterol trafficking into the mitochondria, despite the activation of cholesterol and corticosteroid synthetic genes associated with promoter hypomethylation.
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Affiliation(s)
- Halima Abobaker
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Yun Hu
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Nagmeldin A Omer
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,3College of Allied Medical Sciences, University of Nyala, 155 Nyala, Sudan
| | - Zhen Hou
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Abdulrahman A Idriss
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Ruqian Zhao
- 1MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.,2Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
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20
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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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21
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Olvera-Sánchez S, Esparza-Perusquía M, Flores-Herrera O, Urban-Sosa VA, Martínez F. Aspectos generales del transporte de colesterol en la esteroidogénesis de la placenta humana. TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS 2019. [DOI: 10.22201/fesz.23958723e.2019.0.180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
La placenta humana requiere de colesterol para sintetizar la progesterona que mantiene la relación entre el feto y la madre, lo que le permite concluir de manera exitosa el embarazo. La placenta incorpora el colesterol principalmente a través de las lipoproteínas de baja densidad (LDL) que se obtienen del torrente circulatorio materno por un mecanismo de endocitosis. A los endosomas que se generan en este proceso se les unen varias proteínas conformando los endosomas tardíos, que degradan las LDL y liberan el colesterol a las mitocondrias del sinciciotrofoblasto que lo transforman en pregnenolona y posteriormente en progesterona. Las proteínas de fusión de membranas denominados complejos SNARE participan en la liberación del colesterol en sitios de contacto específicos en donde se localizan las proteínas mitocondriales responsables de la esteroidogénesis.
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Luo J, Jiang LY, Yang H, Song BL. Intracellular Cholesterol Transport by Sterol Transfer Proteins at Membrane Contact Sites. Trends Biochem Sci 2019; 44:273-292. [DOI: 10.1016/j.tibs.2018.10.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/06/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022]
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23
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Shan A, Li M, Li X, Li Y, Yan M, Xian P, Chang Y, Chen X, Tang NJ. BDE-47 Decreases Progesterone Levels in BeWo Cells by Interfering with Mitochondrial Functions and Genes Related to Cholesterol Transport. Chem Res Toxicol 2019; 32:621-628. [PMID: 30714368 DOI: 10.1021/acs.chemrestox.8b00312] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) have been reported to exert reproductive endocrine toxicity, but the mechanisms for this process remain unclear. Currently available studies have concentrated on the enzymatic reactions during steroidogenesis, but the results are not consistent. In this study, we explored the effects of 2,2',4,4'-tertrabromodiphenyl ether (BDE-47) on progesterone biosynthesis and the potential mechanisms in human placental choriocarcinoma cells. The results showed that BDE-47 decreased progesterone production in a dose-dependent manner but had no effect on key enzymes (Cyp11a1 and 3β-HSD). BDE-47 exposure depolarized the mitochondrial membrane potential and downregulated adenosine triphosphate levels. The gene expression levels of Mfn2, Tspo, Atad3, Vdac1, Fis1, and Drp1, which are involved in mitochondrial dynamics and cholesterol transport, were disturbed. The demethylation of some CpG loci of mitochondrial biomarkers (Drp1, Opa1, Vdac2, and Atad3) was induced in the 1 μM BDE-47 exposure group, but no methylation change was observed with 50 μM treatment. Our findings unveiled that the reduction of progesterone synthesis induced by BDE-47 might be associated with cholesterol transportation, mitochondrial dynamics, and mitochondrial functions. These findings provide substantial data on the reproductive endocrine toxicity of PBDEs.
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Affiliation(s)
- Anqi Shan
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Mengxue Li
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Xuejun Li
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Yaoyan Li
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Mengfan Yan
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Ping Xian
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Ying Chang
- Department of Prenatal Diagnoses , Tianjin Center Hospital of Obstetrics and Gynecology , Tianjin 300000 , China
| | - Xi Chen
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
| | - Nai-Jun Tang
- Department of Occupational and Environmental Health, School of Public Health , Tianjin Medical University , Tianjin 300070 , China.,Tianjin Key Laboratory of Environment, Nutrition, and Public Health , Tianjin Medical University , Tianjin 300070 , China
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Ratner MH, Kumaresan V, Farb DH. Neurosteroid Actions in Memory and Neurologic/Neuropsychiatric Disorders. Front Endocrinol (Lausanne) 2019; 10:169. [PMID: 31024441 PMCID: PMC6465949 DOI: 10.3389/fendo.2019.00169] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/28/2019] [Indexed: 12/24/2022] Open
Abstract
Memory dysfunction is a symptomatic feature of many neurologic and neuropsychiatric disorders; however, the basic underlying mechanisms of memory and altered states of circuitry function associated with disorders of memory remain a vast unexplored territory. The initial discovery of endogenous neurosteroids triggered a quest to elucidate their role as neuromodulators in normal and diseased brain function. In this review, based on the perspective of our own research, the advances leading to the discovery of positive and negative neurosteroid allosteric modulators of GABA type-A (GABAA), NMDA, and non-NMDA type glutamate receptors are brought together in a historical and conceptual framework. We extend the analysis toward a state-of-the art view of how neurosteroid modulation of neural circuitry function may affect memory and memory deficits. By aggregating the results from multiple laboratories using both animal models for disease and human clinical research on neuropsychiatric and age-related neurodegenerative disorders, elements of a circuitry level view begins to emerge. Lastly, the effects of both endogenously active and exogenously administered neurosteroids on neural networks across the life span of women and men point to a possible underlying pharmacological connectome by which these neuromodulators might act to modulate memory across diverse altered states of mind.
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25
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Inner Mitochondrial Translocase Tim50 Is Central in Adrenal and Testicular Steroid Synthesis. Mol Cell Biol 2018; 39:MCB.00484-18. [PMID: 30348838 DOI: 10.1128/mcb.00484-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 10/14/2018] [Indexed: 01/24/2023] Open
Abstract
Adrenal and gonadal mitochondrial metabolic activity requires electrons from cofactors, cholesterol, and a substrate for rapid steroid synthesis, an essential requirement for mammalian survival. Substrate activity depends on its environment, which is regulated by chaperones and mitochondrial translocases. Cytochrome P450 side-chain cleavage enzyme (SCC or CYP11A1) catalyzes cholesterol to pregnenolone conversion, although its mechanism of action is not well understood. We find that SCC is directly imported into the mitochondrial matrix, where its N-terminal sequence is cleaved sequentially, after which it becomes activated following the second cleavage, which is dependent on the folding of the protein. Following integration of the SCC C terminus into the TIM23 complex, amino acids 141 to 146 interact with the intermembrane-exposed Tim50 protein, forming a large complex. The absence of Tim50 or its mutation reduced enzymatic activity. For the first time, we report that a protein activated at the matrix remains mostly unfolded and is transported back to the IMS to integrate with the TIM23 translocase complex and align with the Tim50 protein. Amino acid changes that suppress the association of Tim50 with SCC ablate metabolic activity. Thus, the TIM23 complex is the central regulator of metabolism guided by Tim50.
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26
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Wang X, Zou Z, Yang Z, Jiang S, Lu Y, Wang D, Dong Z, Xu S, Zhu L. HIF 1 inhibits StAR transcription and testosterone synthesis in murine Leydig cells. J Mol Endocrinol 2018; 62:JME-18-0148.R2. [PMID: 30400066 DOI: 10.1530/jme-18-0148] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/18/2018] [Indexed: 12/12/2022]
Abstract
Hypoxia-inducible factor-1 (HIF1) is a critical transcription factor involved in cell response to hypoxia. Under physiological conditions, its a subunit is rapidly degraded in most tissues except testes. HIF1 is stably expressed in Leydig cells, which are the main source of testosterone for male, and might bind to the promoter region of steroidogenic acute regulatory protein (Star), which is necessary for the testosterone synthesis, according to software analysis. This study aims to identify the binding sites of HIF1 on Star promoter and its transcriptional regulation of Star to affect testosterone synthesis. Testosterone level and steroid synthesis-related proteins were determined in male Balb/C mice exposed to hypoxia (8% O2). While HIF1 was upregulated, the testosterone level was significantly decreased. This was further confirmed by in vitro experiments with rat primary Leydig cells or TM3 cells exposed to hypoxia (1% O2), CoCl2 or DFX to raise HIF1. The decline of testosterone was reversed by pregnenolone but not cAMP, indicating the cholesterol transport disorder as the main cause. In agreement, StAR expression level was decreased in response to HIF1, while 3b-hydroxysteroid dehydrogenase, 17b-hydroxysteroid dehydrogenase and p450scc did not exhibit significant changes. By ChIP, EMSA supershift and dual-luciferase reporter assays, HIF1 was found to bind to the Star promoter region and repress the expression of StAR. Mutation assays identified three HIF1-binding sites on mouse Star promoter. These findings indicate that HIF1 represses Star transcription through directly binding to the Star promoter at -2082/-2078, -2064/-2060 and -1910/-1906, leading to the negative regulation of testosterone synthesis.
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Affiliation(s)
- Xueting Wang
- X Wang, Biochemisty, Institute of Nautical Medicine, Nantong, China
| | - Zhiran Zou
- Z Zou, Biochemisty, Institute of Nautical Medicine, Nantong, China
| | - Zhihui Yang
- Z Yang, Biochemistry, Institute of Nautical Medicine, Nantong, China
| | - Shan Jiang
- S Jiang, Biochemisty, Institute of Nautical Medicine, Nantong, China
| | - Yapeng Lu
- Y Lu, Biochemisty, Institute of Nautical Medicine, Nantong, China
| | - Dan Wang
- D Wang, Biochemisty, Institute of Nautical Medicine, Nantong, China
| | - Zhangji Dong
- Z Dong, Molecular Biology, Key laboratory of neuroregeneration of Jiangsu and Ministry of Education, Nantong, China
| | - Sha Xu
- S Xu, physiology, Medical College of Soochow University, Suzhou, China
| | - Li Zhu
- L Zhu, Biochemisty, Institute of Nautical Medicine, Nantong, China
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27
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Caterino M, Ruoppolo M, Mandola A, Costanzo M, Orrù S, Imperlini E. Protein-protein interaction networks as a new perspective to evaluate distinct functional roles of voltage-dependent anion channel isoforms. MOLECULAR BIOSYSTEMS 2018; 13:2466-2476. [PMID: 29028058 DOI: 10.1039/c7mb00434f] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Voltage-dependent anion channels (VDACs) are a family of three mitochondrial porins and the most abundant integral membrane proteins of the mitochondrial outer membrane (MOM). VDACs are known to be involved in metabolite/ion transport across the MOM and in many cellular processes ranging from mitochondria-mediated apoptosis to the control of energy metabolism, by interacting with cytosolic, mitochondrial and cytoskeletal proteins and other membrane channels. Despite redundancy and compensatory mechanisms among VDAC isoforms, they display not only different channel properties and protein expression levels, but also distinct protein partners. Here, we review the known protein interactions for each VDAC isoform in order to shed light on their peculiar roles in physiological and pathological conditions. As proteins associated with the MOM, VDAC opening/closure as a metabolic checkpoint is regulated by protein-protein interactions, and is of pharmacological interest in pathological conditions such as cancer. The interactions involving VDAC1 have been characterized more in depth than those involving VDAC2 and VDAC3. Nevertheless, the so far explored VDAC-protein interactions for each isoform show that VDAC1 is mainly involved in the maintenance of cellular homeostasis and in pro-apoptotic processes, whereas VDAC2 displays an anti-apoptotic role. Despite there being limited information on VDAC3, this isoform could contribute to mitochondrial protein quality control and act as a marker of oxidative status. In pathological conditions, namely neurodegenerative and cardiovascular diseases, both VDAC1 and VDAC2 establish abnormal interactions aimed to counteract the mitochondrial dysfunction which contributes to end-organ damage.
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Affiliation(s)
- Marianna Caterino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
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28
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Kennedy BE, Charman M, Karten B. Measurement of Mitochondrial Cholesterol Import Using a Mitochondria-Targeted CYP11A1 Fusion Construct. Methods Mol Biol 2018; 1583:163-184. [PMID: 28205173 DOI: 10.1007/978-1-4939-6875-6_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
All animal membranes require cholesterol as an essential regulator of biophysical properties and function, but the levels of cholesterol vary widely among different subcellular compartments. Mitochondria, and in particular the inner mitochondrial membrane, have the lowest levels of cholesterol in the cell. Nevertheless, mitochondria need cholesterol for membrane maintenance and biogenesis, as well as oxysterol, steroid, and hepatic bile acid production. Alterations in mitochondrial cholesterol have been associated with a range of pathological conditions, including cancer, hepatosteatosis, cardiac ischemia, Alzheimer's, and Niemann-Pick Type C Disease. The mechanisms of mitochondrial cholesterol import are not fully elucidated yet, and may vary in different cell types and environmental conditions. Measuring cholesterol trafficking to the mitochondrial membranes is technically challenging because of its low abundance; for example, traditional pulse-chase experiments with isotope-labeled cholesterol are not feasible. Here, we describe improvements to a method first developed by the Miller group at the University of California to measure cholesterol trafficking to the inner mitochondrial membrane (IMM) through the conversion of cholesterol to pregnenolone. This method uses a mitochondria-targeted, ectopically expressed fusion construct of CYP11A1, ferredoxin reductase and ferredoxin. Pregnenolone is formed exclusively from cholesterol at the IMM, and can be analyzed with high sensitivity and specificity through ELISA or radioimmunoassay of the medium/buffer to reflect mitochondrial cholesterol import. This assay can be used to investigate the effects of genetic or pharmacological interventions on mitochondrial cholesterol import in cultured cells or isolated mitochondria.
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Affiliation(s)
- Barry E Kennedy
- Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building 9G, 5850 College Street, Halifax, NS, Canada, B3H 4R2
| | - Mark Charman
- Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building 9G, 5850 College Street, Halifax, NS, Canada, B3H 4R2
| | - Barbara Karten
- Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building 9G, 5850 College Street, Halifax, NS, Canada, B3H 4R2.
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29
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Liang JJ, Rasmusson AM. Overview of the Molecular Steps in Steroidogenesis of the GABAergic Neurosteroids Allopregnanolone and Pregnanolone. CHRONIC STRESS (THOUSAND OAKS, CALIF.) 2018; 2:2470547018818555. [PMID: 32440589 PMCID: PMC7219929 DOI: 10.1177/2470547018818555] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/19/2018] [Indexed: 12/23/2022]
Abstract
Allopregnanolone and pregnanolone-neurosteroids synthesized from progesterone in the brain, adrenal gland, ovary and testis-have been implicated in a range of neuropsychiatric conditions including seizure disorders, post-traumatic stress disorder, major depression, post-partum depression, pre-menstrual dysphoric disorder, chronic pain, Parkinson's disease, Alzheimer's disease, neurotrauma, and stroke. Allopregnanolone and pregnanolone equipotently facilitate the effects of gamma-amino-butyric acid (GABA) at GABAA receptors, and when sulfated, antagonize N-methyl-D-aspartate receptors. They play myriad roles in neurophysiological homeostasis and adaptation to stress while exerting anxiolytic, antidepressant, anti-nociceptive, anticonvulsant, anti-inflammatory, sleep promoting, memory stabilizing, neuroprotective, pro-myelinating, and neurogenic effects. Given that these neurosteroids are synthesized de novo on demand, this review details the molecular steps involved in the biochemical conversion of cholesterol to allopregnanolone and pregnanolone within steroidogenic cells. Although much is known about the early steps in neurosteroidogenesis, less is known about transcriptional, translational, and post-translational processes in allopregnanolone- and pregnanolone-specific synthesis. Further research to elucidate these mechanisms as well as to optimize the timing and dose of interventions aimed at altering the synthesis or levels of these neurosteroids is much needed. This should include the development of novel therapeutics for the many neuropsychiatric conditions to which dysregulation of these neurosteroids contributes.
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Affiliation(s)
| | - Ann M. Rasmusson
- Boston
University School of Medicine, Boston, MA,
USA
- National Center for PTSD, Women’s Health
Science Division, Department of Veterans Affairs, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA,
USA
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30
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Regulation of Mitochondrial, Cellular, and Organismal Functions by TSPO. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:103-136. [PMID: 29413517 DOI: 10.1016/bs.apha.2017.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In 1999, the enigma of the 18kDa mitochondrial translocator protein (TSPO), also known as the peripheral-type benzodiazepine receptor, was the seeming disparity of the many functions attributed to TSPO, ranging from the potential of TSPO acting as a housekeeping gene at molecular biological levels to adaptations to stress, and even involvement in higher emotional and cognitive functioning, such as anxiety and depression. In the years since then, knowledge regarding the many functions modulated by TSPO has expanded, and understanding has deepened. In addition, new functions could be firmly associated with TSPO, such as regulation of programmed cell death and modulation of gene expression. Interestingly, control by the mitochondrial TSPO over both of these life and death functions appears to include Ca++ homeostasis, generation of reactive oxygen species (ROS), and ATP production. Other mitochondrial functions under TSPO control are considered to be steroidogenesis and tetrapyrrole metabolism. As TSPO effects on gene expression and on programmed cell death can be related to the wide range of functions that can be associated with TSPO, several of these five elements of Ca++, ROS, ATP, steroids, and tetrapyrroles may indeed form the basis of TSPO's capability to operate as a multifunctional housekeeping gene to maintain homeostasis of the cell and of the whole multicellular organism.
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31
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The heat shock protein 60 promotes progesterone synthesis in mitochondria of JEG-3 cells. Reprod Biol 2017; 17:154-161. [DOI: 10.1016/j.repbio.2017.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/05/2017] [Accepted: 04/12/2017] [Indexed: 11/22/2022]
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32
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Piya A, Kaur J, Rice AM, Bose HS. De novo disruption of promoter and exon 1 of STAR gene reveals essential role for gonadal development. Endocrinol Diabetes Metab Case Rep 2017; 2017:EDM160120. [PMID: 28458886 PMCID: PMC5404458 DOI: 10.1530/edm-16-0120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 02/10/2017] [Indexed: 11/08/2022] Open
Abstract
SUMMARY Cholesterol transport into the mitochondria is required for synthesis of the first steroid, pregnenolone. Cholesterol is transported by the steroidogenic acute regulatory protein (STAR), which acts at the outer mitochondrial membrane prior to its import. Mutations in the STAR protein result in lipoid congenital adrenal hyperplasia (CAH). Although the STAR protein consists of seven exons, biochemical analysis in nonsteroidogenic COS-1 cells showed that the first two were not essential for pregnenolone synthesis. Here, we present a patient with ambiguous genitalia, salt-lossing crisis within two weeks after birth and low cortisol levels. Sequence analysis of the STAR, including the exon-intron boundaries, showed the complete deletion of exon 1 as well as more than 50 nucleotides upstream of STAR promoter. Mitochondrial protein import with the translated protein through synthesis cassette of the mutant STAR lacking exon 1 showed protein translation, but it is less likely to have synthesized without a promoter in our patient. Thus, a full-length STAR gene is necessary for physiological mitochondrial cholesterol transport in vivo. LEARNING POINTS STAR exon 1 deletion caused lipoid CAH.Exon 1 substitution does not affect biochemical activity.StAR promoter is responsible for gonadal development.
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Affiliation(s)
- Anil Piya
- Laboratory of Biochemistry, Mercer University School of Medicine, Savannah, GeorgiaUSA.,Division of Pediatric Endocrinology, Memorial University Medical Center, Savannah, GeorgiaUSA
| | - Jasmeet Kaur
- Laboratory of Biochemistry, Mercer University School of Medicine, Savannah, GeorgiaUSA.,Anderson Cancer Institute, Memorial University Medical Center, Savannah, GeorgiaUSA
| | - Alan M Rice
- Division of Pediatric Endocrinology, Memorial University Medical Center, Savannah, GeorgiaUSA.,Augusta University School of Medicine, Augusta, GeorgiaUSA
| | - Himangshu S Bose
- Laboratory of Biochemistry, Mercer University School of Medicine, Savannah, GeorgiaUSA.,Anderson Cancer Institute, Memorial University Medical Center, Savannah, GeorgiaUSA
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33
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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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34
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Prasad M, Pawlak KJ, Burak WE, Perry EE, Marshall B, Whittal RM, Bose HS. Mitochondrial metabolic regulation by GRP78. SCIENCE ADVANCES 2017; 3:e1602038. [PMID: 28275724 PMCID: PMC5325540 DOI: 10.1126/sciadv.1602038] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/25/2017] [Indexed: 05/08/2023]
Abstract
Steroids, essential for mammalian survival, are initiated by cholesterol transport by steroidogenic acute regulatory protein (StAR). Appropriate protein folding is an essential requirement of activity. Endoplasmic reticulum (ER) chaperones assist in folding of cytoplasmic proteins, whereas mitochondrial chaperones fold only mitochondrial proteins. We show that glucose regulatory protein 78 (GRP78), a master ER chaperone, is also present at the mitochondria-associated ER membrane (MAM), where it folds StAR for delivery to the outer mitochondrial membrane. StAR expression and activity are drastically reduced following GRP78 knockdown. StAR folding starts at the MAM region; thus, its cholesterol fostering capacity is regulated by GRP78 long before StAR reaches the mitochondria. In summary, GRP78 is an acute regulator of steroidogenesis at the MAM, regulating the intermediate folding of StAR that is crucial for its activity.
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Affiliation(s)
- Manoj Prasad
- Laboratory of Biochemistry and Cell Biology, Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
| | - Kevin J. Pawlak
- Laboratory of Biochemistry and Cell Biology, Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
| | - William E. Burak
- Laboratory of Biochemistry and Cell Biology, Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
- Anderson Cancer Institute, Memorial University Medical Center, Savannah, GA 31404, USA
| | - Elizabeth E. Perry
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA 30912, USA
| | - Brendan Marshall
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA 30912, USA
| | - Randy M. Whittal
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Himangshu S. Bose
- Laboratory of Biochemistry and Cell Biology, Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
- Anderson Cancer Institute, Memorial University Medical Center, Savannah, GA 31404, USA
- Corresponding author.
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35
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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: 121] [Impact Index Per Article: 17.3] [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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36
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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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Endoplasmic Reticulum Stress Enhances Mitochondrial Metabolic Activity in Mammalian Adrenals and Gonads. Mol Cell Biol 2016; 36:3058-3074. [PMID: 27697863 DOI: 10.1128/mcb.00411-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/23/2016] [Indexed: 01/21/2023] Open
Abstract
The acute response to stress consists of a series of physiological programs to promote survival by generating glucocorticoids and activating stress response genes that increase the synthesis of many chaperone proteins specific to individual organelles. In the endoplasmic reticulum (ER), short-term stress triggers activation of the unfolded protein response (UPR) module that either leads to neutralization of the initial stress or adaptation to it; chronic stress favors cell death. UPR induces expression of the transcription factor, C/EBP homology protein (CHOP), and its deletion protects against the lethal consequences of prolonged UPR. Here, we show that stress-induced CHOP expression coincides with increased metabolic activity. During stress, the ER and mitochondria come close to each other, resulting in the formation of a complex consisting of the mitochondrial translocase, translocase of outer mitochondrial membrane 22 (Tom22), steroidogenic acute regulatory protein (StAR), and 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2) via its intermembrane space (IMS)-exposed charged unstructured loop region. Stress increased the circulation of phosphates, which elevated pregnenolone synthesis by 2-fold by increasing the stability of 3βHSD2 and its association with the mitochondrion-associated ER membrane (MAM) and mitochondrial proteins. In summary, cytoplasmic CHOP plays a central role in coordinating the interaction of MAM proteins with the outer mitochondrial membrane translocase, Tom22, to activate metabolic activity in the IMS by enhanced phosphate circulation.
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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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Kaur J, Rice AM, O'Connor E, Piya A, Buckler B, Bose HS. Novel SCC mutation in a patient of Mexican descent with sex reversal, salt-losing crisis and adrenal failure. Endocrinol Diabetes Metab Case Rep 2016; 2016:EDM160059. [PMID: 27855232 PMCID: PMC5093401 DOI: 10.1530/edm-16-0059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 11/08/2022] Open
Abstract
Congenital adrenal hyperplasia (CAH) is caused by mutations in cytochrome P450 side chain cleavage enzyme (CYP11A1 and old name, SCC). Errors in cholesterol side chain cleavage by the mitochondrial resident CYP11A1 results in an inadequate amount of pregnenolone production. This study was performed to evaluate the cause of salt-losing crisis and possible adrenal failure in a pediatric patient whose mother had a history of two previous stillbirths and loss of another baby within a week of birth. CAH can appear in any population in any region of the world. The study was conducted at Memorial University Medical Center and Mercer University School of Medicine. The patient was admitted to Pediatric Endocrinology Clinic due to salt-losing crisis and possible adrenal failure. The patient had CAH, an autosomal recessive disease, due to a novel mutation in exon 5 of the CYP11A1 gene, which generated a truncated protein of 286 amino acids compared with wild-type protein that has 521 amino acids (W286X). Although unrelated, both parents are carriers. Mitochondrial protein import analysis of the mutant CYP11A1 in steroidogenic MA-10 cells showed that the protein is imported in a similar fashion as observed for the wild-type protein and was cleaved to a shorter fragment. However, mutant's activity was 10% of that obtained for the wild-type protein in non-steroidogenic COS-1 cells. In a patient of Mexican descent, a homozygous CYP11A1 mutation caused CAH, suggesting that this disease is not geographically restricted even in a homogeneous population. LEARNING POINTS Novel mutation in CYP11A1 causes CAH;This is a pure population from Central Mexico;Novel mutation created early truncated protein.
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Affiliation(s)
- Jasmeet Kaur
- Laboratory of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA; Anderson Cancer Institute, Memorial University Medical Center, Savannah, Georgia, USA
| | - Alan M Rice
- Division of Pediatric Endocrinology, Memorial University Medical Center, Savannah, Georgia, USA; Augusta University School of Medicine, Augusta, Georgia, USA; Neonatology Intensive Care Unit, Memorial University Medical Center, Georgia, USA
| | - Elizabeth O'Connor
- Laboratory of Biochemistry , Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia , USA
| | - Anil Piya
- Division of Pediatric Endocrinology, Memorial University Medical Center, Savannah, Georgia, USA; Neonatology Intensive Care Unit, Memorial University Medical Center, Georgia, USA
| | - Bradley Buckler
- Neonatology Intensive Care Unit , Memorial University Medical Center, Georgia , USA
| | - Himangshu S Bose
- Laboratory of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA; Anderson Cancer Institute, Memorial University Medical Center, Savannah, Georgia, USA
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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: 92] [Impact Index Per Article: 11.5] [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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An Outer Mitochondrial Translocase, Tom22, Is Crucial for Inner Mitochondrial Steroidogenic Regulation in Adrenal and Gonadal Tissues. Mol Cell Biol 2016; 36:1032-47. [PMID: 26787839 DOI: 10.1128/mcb.01107-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/06/2016] [Indexed: 11/20/2022] Open
Abstract
After cholesterol is transported into the mitochondria of steroidogenic tissues, the first steroid, pregnenolone, is synthesized in adrenal and gonadal tissues to initiate steroid synthesis by catalyzing the conversion of pregnenolone to progesterone, which is mediated by the inner mitochondrial enzyme 3β-hydroxysteroid dehydrogenase 2 (3βHSD2). We report that the mitochondrial translocase Tom22 is essential for metabolic conversion, as its knockdown by small interfering RNA (siRNA) completely ablated progesterone conversion in both steroidogenic mouse Leydig MA-10 and human adrenal NCI cells. Tom22 forms a 500-kDa complex with mitochondrial proteins associated with 3βHSD2. Although the absence of Tom22 did not inhibit mitochondrial import of cytochrome P450scc (cytochrome P450 side chain cleavage enzyme) and aldosterone synthase, it did inhibit 3βHSD2 expression. Electron microscopy showed that Tom22 is localized at the outer mitochondrial membrane (OMM), while 3βHSD2 is localized at the inner mitochondrial space (IMS), where it interacts through a specific region with Tom22 with its C-terminal amino acids and a small amino acid segment of Tom22 exposed to the IMS. Therefore, Tom22 is a critical regulator of steroidogenesis, and thus, it is essential for mammalian survival.
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42
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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: 34] [Impact Index Per Article: 4.3] [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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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: 51] [Impact Index Per Article: 6.4] [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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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: 64] [Impact Index Per Article: 8.0] [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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45
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Shen WJ, Azhar S, Kraemer FB. Lipid droplets and steroidogenic cells. Exp Cell Res 2015; 340:209-14. [PMID: 26639173 DOI: 10.1016/j.yexcr.2015.11.024] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 02/05/2023]
Abstract
Lipid droplets (LDs) in steroidogenic tissues have a cholesteryl ester (CE) core surrounded by a phospholipid monolayer that is coated with associated proteins. Compared with other tissues, they tend to be smaller in size and more numerous in numbers. These LDs are enriched with PLIN1c, PLIN2 and PLIN3. Both CIDE A and B are found in mouse ovary. Free cholesterol (FC) released upon hormone stimulation from LDs is the preferred source of cholesterol substrate for steroidogenesis, and HSL is the major neutral cholesterol esterase mediating the conversion of CEs to FC. Through the interaction of HSL with vimentin and StAR, FC is translocated to mitochondria for steroid hormone production. Proteomic analyses of LDs isolated from loaded primary ovarian granulosa cells, mouse MLTC-1 Leydig tumor cells and mouse testes revealed LD associated proteins that are actively involved in modulating lipid homeostasis along with a number of steroidogenic enzymes. Microscopy analysis confirmed the localization of many of these proteins to LDs. These studies broaden the role of LDs to include being a platform for functional steroidogenic enzyme activity or as a port for transferring steroidogenic enzymes and/or steroid intermediates, in addition to being a storage depot for CEs.
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Affiliation(s)
- Wen-Jun Shen
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States
| | - Salman Azhar
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States
| | - Fredric B Kraemer
- Division of Endocrinology, Gerontology and Metabolism, Stanford University, Stanford, CA 94305, United States; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, United States.
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Martinez F, Olvera-Sanchez S, Esparza-Perusquia M, Gomez-Chang E, Flores-Herrera O. Multiple functions of syncytiotrophoblast mitochondria. Steroids 2015; 103:11-22. [PMID: 26435077 DOI: 10.1016/j.steroids.2015.09.006] [Citation(s) in RCA: 34] [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: 02/02/2015] [Revised: 09/16/2015] [Accepted: 09/27/2015] [Indexed: 12/17/2022]
Abstract
The human placenta plays a central role in pregnancy, and the syncytiotrophoblast cells are the main components of the placenta that support the relationship between the mother and fetus, in apart through the production of progesterone. In this review, the metabolic processes performed by syncytiotrophoblast mitochondria associated with placental steroidogenesis are described. The metabolism of cholesterol, specifically how this steroid hormone precursor reaches the mitochondria, and its transformation into progesterone are reviewed. The role of nucleotides in steroidogenesis, as well as the mechanisms associated with signal transduction through protein phosphorylation and dephosphorylation of proteins is discussed. Finally, topics that require further research are identified, including the need for new techniques to study the syncytiotrophoblast in situ using non-invasive methods.
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Affiliation(s)
- Federico Martinez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico.
| | - Sofia Olvera-Sanchez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Mercedes Esparza-Perusquia
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Erika Gomez-Chang
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
| | - Oscar Flores-Herrera
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, Coyoacan 04510, México, D.F., Mexico
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Papadopoulos V, Aghazadeh Y, Fan J, Campioli E, Zirkin B, Midzak A. Translocator protein-mediated pharmacology of cholesterol transport and steroidogenesis. Mol Cell Endocrinol 2015; 408:90-8. [PMID: 25818881 PMCID: PMC4417383 DOI: 10.1016/j.mce.2015.03.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/17/2022]
Abstract
Steroidogenesis begins with cholesterol transfer into mitochondria through the transduceosome, a complex composed of cytosolic proteins that include steroidogenesis acute regulatory protein (STAR), 14-3-3 adaptor proteins, and the outer mitochondrial membrane proteins Translocator Protein (TSPO) and Voltage-Dependent Anion Channel (VDAC). TSPO is a drug- and cholesterol-binding protein found at particularly high levels in steroid synthesizing cells. Its aberrant expression has been linked to cancer, neurodegeneration, neuropsychiatric disorders and primary hypogonadism. Brain steroids serve as local regulators of neural development and excitability. Reduced levels of these steroids have been linked to depression, anxiety and neurodegeneration. Reduced serum testosterone is common among subfertile young men and aging men, and is associated with depression, metabolic syndrome and reduced sexual function. Although testosterone-replacement therapy is available, there are undesired side-effects. TSPO drug ligands have been proposed as therapeutic agents to regulate steroid levels in the brain and testis.
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Affiliation(s)
- Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada.
| | - Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Andrew Midzak
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Departments of Biochemistry, McGill University, Montreal, Quebec, Canada
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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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49
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Castillo AF, Orlando U, Helfenberger KE, Poderoso C, Podesta EJ. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis. Mol Cell Endocrinol 2015; 408:73-9. [PMID: 25540920 DOI: 10.1016/j.mce.2014.12.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 12/16/2022]
Abstract
The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.
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Affiliation(s)
- Ana F Castillo
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ulises Orlando
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Katia E Helfenberger
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Cecilia Poderoso
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ernesto J Podesta
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina.
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50
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Aghazadeh Y, Zirkin BR, Papadopoulos V. Pharmacological regulation of the cholesterol transport machinery in steroidogenic cells of the testis. VITAMINS AND HORMONES 2015; 98:189-227. [PMID: 25817870 DOI: 10.1016/bs.vh.2014.12.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Reduced serum testosterone (T), or hypogonadism, is estimated to affect about 5 million American men, including both aging and young men. Low serum T has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass and bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Administering exogenous T, known as T-replacement therapy (TRT), reverses many of the symptoms of low T levels. However, this treatment can result in luteinizing hormone suppression which, in turn, can lead to reduced sperm numbers and infertility, making TRT inappropriate for men who wish to father children. Additionally, TRT may result in supraphysiologic T levels, skin irritation, and T transfer to others upon contact; and there may be increased risk of prostate cancer and cardiovascular disease, particularly in aging men. Therefore, the development of alternate therapies for treating hypogonadism would be highly desirable. To do so requires greater understanding of the series of steps leading to T formation and how they are regulated, and the identification of key steps that are amenable to pharmacological modulation so as to induce T production. We review herein our current understanding of mechanisms underlying the pharmacological induction of T formation in hypogonadal testis.
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Affiliation(s)
- Yasaman Aghazadeh
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Barry R Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Biochemistry, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
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