101
|
Fan J, Wang K, Zirkin B, Papadopoulos V. CRISPR/Cas9‒Mediated Tspo Gene Mutations Lead to Reduced Mitochondrial Membrane Potential and Steroid Formation in MA-10 Mouse Tumor Leydig Cells. Endocrinology 2018; 159:1130-1146. [PMID: 29300865 PMCID: PMC5793793 DOI: 10.1210/en.2017-03065] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 12/21/2017] [Indexed: 12/17/2022]
Abstract
The outer mitochondrial membrane translocator protein (TSPO) binds cholesterol with high affinity and is involved in mediating its delivery into mitochondria, the rate-limiting step in hormone-induced steroidogenesis. Specific ligand binding to TSPO has been shown to initiate steroid formation. However, recent studies of the genetic deletion of Tspo have provided conflicting results. Here, we address and extend previous studies by examining the effects of Tspo-specific mutations on steroid formation in hormone- and cyclic adenosine monophosphate (cAMP)-responsive MA-10 cells, using the CRISPR/Cas9 system. Two mutant subcell lines, nG1 and G2G, each carrying a Tspo exon2-specific genome modification, and two control subcell lines, G1 and HH, each carrying a wild-type Tspo, were produced. In response to dibutyryl cAMP, the nG1 and G2G cells produced progesterone at levels significantly lower than those produced by the corresponding control cells G1 and HH. Neutral lipid homeostasis, which provides free cholesterol for steroid biosynthesis, was altered significantly in the Tspo mutant cells. Interestingly, the mitochondrial membrane potential (ΔΨm) of the Tspo mutant cells was significantly reduced compared with that of the control cells, likely because of TSPO interactions with the voltage-dependent anion channel and tubulin at the outer mitochondrial membrane. Steroidogenic acute regulatory protein (STAR) expression was induced in nG1 cells, suggesting that reduced TSPO affected STAR synthesis and/or processing. Taken together, these results provide further evidence for the critical role of TSPO in steroid biosynthesis and suggest that it may function at least in part via its regulation of ΔΨm and effects on STAR.
Collapse
Affiliation(s)
- Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Kevin Wang
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| |
Collapse
|
102
|
Papadopoulos V, Fan J, Zirkin B. Translocator protein (18 kDa): an update on its function in steroidogenesis. J Neuroendocrinol 2018; 30:10.1111/jne.12500. [PMID: 28667781 PMCID: PMC5748373 DOI: 10.1111/jne.12500] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 12/15/2022]
Abstract
Translocator protein (18 kDa) (TSPO) is a ubiquitous mitochondrial protein. Studies of its responses to drug and endogenous ligands have shown TSPO to be involved either directly or indirectly in numerous biological functions, including mitochondrial cholesterol transport and steroid hormone biosynthesis, porphyrin transport and heme synthesis, apoptosis, cell proliferation, and anion transport. Localised to the outer mitochondrial membrane of steroidogenic cells, TSPO has been shown to associate with cytosolic and mitochondrial proteins as part of a large multiprotein complex involved in mitochondrial cholesterol transport, the rate-limiting step in steroidogenesis. There is general agreement as to the structure and pharmacology of TSPO. Stimulation of TSPO has been shown to have therapeutic use as anxiolytics by inducing allopregnanolone production in the brain, and also potentially for re-establishing androgen levels in hypogonadal ageing animals. Until recently, there has been general agreement regarding the role of TSPO in steroidogenesis. However, recent studies involving genetic depletion of TSPO in mice have created controversy about the role of this protein in steroid and heme synthesis. We review the data on the structure and function of TSPO, as well as the recent results obtained using various genetic animal models. Taken together, these studies suggest that TSPO is a unique mitochondrial pharmacological target for diseases that involve increased mitochondrial activity, including steroidogenesis. Although there is no known mammalian species that lacks TSPO, it is likely that, because of the importance of this ancient protein in evolution and mitochondrial function, redundant mechanisms may exist to replace it under circumstances when it is removed.
Collapse
Affiliation(s)
- Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
- Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
| |
Collapse
|
103
|
Friend or foe? Mitochondria as a pharmacological target in cancer treatment. Future Med Chem 2017; 9:2197-2210. [PMID: 29182013 DOI: 10.4155/fmc-2017-0110] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mitochondria have acquired numerous functions over the course of evolution, such as those involved in controlling energy production, cellular metabolism, cell survival, apoptosis and autophagy within host cells. Tumor cells can develop defects in mitochondrial function, presenting a potential strategy for designing selective anticancer therapies. Therefore, cancer has been the main focus of recent research to uncover possible mitochondrial targets for therapeutic benefit. This comprehensive review covers not only the recent discoveries of the roles of mitochondria in cancer development, progression and therapeutic implications but also the findings regarding emerging mitochondrial therapeutic targets and mitochondria-targeted agents. Current challenges and future directions for developments and applications of mitochondrial-targeted therapeutics are also discussed.
Collapse
|
104
|
Baudier J. ATAD3 proteins: brokers of a mitochondria-endoplasmic reticulum connection in mammalian cells. Biol Rev Camb Philos Soc 2017; 93:827-844. [PMID: 28941010 DOI: 10.1111/brv.12373] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/22/2017] [Accepted: 08/25/2017] [Indexed: 12/25/2022]
Abstract
In yeast, a sequence of physical and genetic interactions termed the endoplasmic reticulum (ER)-mitochondria organizing network (ERMIONE) controls mitochondria-ER interactions and mitochondrial biogenesis. Several functions that characterize ERMIONE complexes are conserved in mammalian cells, suggesting that a similar tethering complex must exist in metazoans. Recent studies have identified a new family of nuclear-encoded ATPases associated with diverse cellular activities (AAA+-ATPase) mitochondrial membrane proteins specific to multicellular eukaryotes, called the ATPase family AAA domain-containing protein 3 (ATAD3) proteins (ATAD3A and ATAD3B). These proteins are crucial for normal mitochondrial-ER interactions and lie at the heart of processes underlying mitochondrial biogenesis. ATAD3A orthologues have been studied in flies, worms, and mammals, highlighting the widespread importance of this gene during embryonic development and in adulthood. ATAD3A is a downstream effector of target of rapamycin (TOR) signalling in Drosophila and exhibits typical features of proteins from the ERMIONE-like complex in metazoans. In humans, mutations in the ATAD3A gene represent a new link between altered mitochondrial-ER interaction and recognizable neurological syndromes. The primate-specific ATAD3B protein is a biomarker of pluripotent embryonic stem cells. Through negative regulation of ATAD3A function, ATAD3B supports mitochondrial stemness properties.
Collapse
Affiliation(s)
- Jacques Baudier
- Aix Marseille Université, CNRS, IBDM, 13284, Marseille Cedex 07, France.,Institut de Biologie du Développement de Marseille-UMR CNRS 7288, 13288, Marseille Cedex 9, France
| |
Collapse
|
105
|
Desai R, Frazier AE, Durigon R, Patel H, Jones AW, Dalla Rosa I, Lake NJ, Compton AG, Mountford HS, Tucker EJ, Mitchell ALR, Jackson D, Sesay A, Di Re M, van den Heuvel LP, Burke D, Francis D, Lunke S, McGillivray G, Mandelstam S, Mochel F, Keren B, Jardel C, Turner AM, Ian Andrews P, Smeitink J, Spelbrink JN, Heales SJ, Kohda M, Ohtake A, Murayama K, Okazaki Y, Lombès A, Holt IJ, Thorburn DR, Spinazzola A. ATAD3 gene cluster deletions cause cerebellar dysfunction associated with altered mitochondrial DNA and cholesterol metabolism. Brain 2017; 140:1595-1610. [PMID: 28549128 PMCID: PMC5445257 DOI: 10.1093/brain/awx094] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/09/2017] [Indexed: 12/03/2022] Open
Abstract
Although mitochondrial disorders are clinically heterogeneous, they frequently involve the central nervous system and are among the most common neurogenetic disorders. Identifying the causal genes has benefited enormously from advances in high-throughput sequencing technologies; however, once the defect is known, researchers face the challenge of deciphering the underlying disease mechanism. Here we characterize large biallelic deletions in the region encoding the ATAD3C, ATAD3B and ATAD3A genes. Although high homology complicates genomic analysis of the ATAD3 defects, they can be identified by targeted analysis of standard single nucleotide polymorphism array and whole exome sequencing data. We report deletions that generate chimeric ATAD3B/ATAD3A fusion genes in individuals from four unrelated families with fatal congenital pontocerebellar hypoplasia, whereas a case with genomic rearrangements affecting the ATAD3C/ATAD3B genes on one allele and ATAD3B/ATAD3A genes on the other displays later-onset encephalopathy with cerebellar atrophy, ataxia and dystonia. Fibroblasts from affected individuals display mitochondrial DNA abnormalities, associated with multiple indicators of altered cholesterol metabolism. Moreover, drug-induced perturbations of cholesterol homeostasis cause mitochondrial DNA disorganization in control cells, while mitochondrial DNA aggregation in the genetic cholesterol trafficking disorder Niemann-Pick type C disease further corroborates the interdependence of mitochondrial DNA organization and cholesterol. These data demonstrate the integration of mitochondria in cellular cholesterol homeostasis, in which ATAD3 plays a critical role. The dual problem of perturbed cholesterol metabolism and mitochondrial dysfunction could be widespread in neurological and neurodegenerative diseases.
Collapse
Affiliation(s)
- Radha Desai
- MRC Laboratory, Mill Hill, London NW71AA, UK
| | - Ann E Frazier
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia
| | - Romina Durigon
- Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK
| | - Harshil Patel
- Bioinformatics and Biostatistics, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Aleck W Jones
- Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK
| | - Ilaria Dalla Rosa
- Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK
| | - Nicole J Lake
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia
| | - Alison G Compton
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia
| | - Hayley S Mountford
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia
| | - Elena J Tucker
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia
| | - Alice L R Mitchell
- Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK
| | - Deborah Jackson
- Bioinformatics and Biostatistics, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Abdul Sesay
- Bioinformatics and Biostatistics, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Miriam Di Re
- Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY, UK
| | - Lambert P van den Heuvel
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Derek Burke
- Department of Genetics and Genomic Medicine, Institute of Child Health, University College London, London, UK and Laboratory Medicine, Great Ormond Street Hospital, London, UK
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne VIC 3052, Australia
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne VIC 3052, Australia.,Department of Pathology, University of Melbourne, Melbourne 3052, Australia
| | - George McGillivray
- MRC Laboratory, Mill Hill, London NW71AA, UK.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne VIC 3052, Australia
| | - Simone Mandelstam
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia.,The Florey Institute of Neuroscience and Mental Health Melbourne, Australia.,Departments of Radiology and Paediatrics, University of Melbourne, Melbourne, Australia
| | - Fanny Mochel
- AP-HP, Department of Genetics, GHU Pitié-Salpêtrière, Paris, F-75651 France.,Inserm U975; CNRS UMR 7225, ICM; F-75013, Paris, France
| | - Boris Keren
- Inserm U975; CNRS UMR 7225, ICM; F-75013, Paris, France.,AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris, F-75651 France
| | - Claude Jardel
- AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris, F-75651 France.,Inserm U1016; CNRS UMR 8104; Université Paris-Descartes-Paris 5; Institut Cochin, 75014 Paris, France
| | - Anne M Turner
- Department of Clinical Genetics, Sydney Children's Hospital, Sydney, NSW, Australia.,School of Women's and Children's Health, University of New South Wales, Kensington, NSW, Australia
| | - P Ian Andrews
- School of Women's and Children's Health, University of New South Wales, Kensington, NSW, Australia.,Department of Paediatric Neurology, Sydney Children's Hospital, Sydney, NSW, Australia
| | - Jan Smeitink
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johannes N Spelbrink
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Simon J Heales
- Department of Genetics and Genomic Medicine, Institute of Child Health, University College London, London, UK and Laboratory Medicine, Great Ormond Street Hospital, London, UK.,Department of Molecular Neuroscience, Institute of Neurology, University College London, Queen Square, London, UK
| | - Masakazu Kohda
- Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Hidaka-shi, Saitama, Japan
| | - Akira Ohtake
- Department of Pediatrics, Saitama Medical University, Moroyama-machi, Iruma-gun, Saitama, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yasushi Okazaki
- Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Hidaka-shi, Saitama, Japan.,Division of Functional Genomics and Systems Medicine, Research Center for Genomic Medicine, Saitama Medical University, Hidaka-shi, Saitama, Japan
| | - Anne Lombès
- MRC Laboratory, Mill Hill, London NW71AA, UK.,Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ian J Holt
- MRC Laboratory, Mill Hill, London NW71AA, UK.,Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK.,Biodonostia Health Research Institute, 20014 San Sebastián, Spain. IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - David R Thorburn
- Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne VIC 3052, Australia
| | - Antonella Spinazzola
- Department of Clinical Neurosciences, Institute of Neurology, Royal Free Campus, University College London, NW3 2PF, UK.,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| |
Collapse
|
106
|
Identifying mitotane-induced mitochondria-associated membranes dysfunctions: metabolomic and lipidomic approaches. Oncotarget 2017; 8:109924-109940. [PMID: 29299119 PMCID: PMC5746354 DOI: 10.18632/oncotarget.18968] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 06/18/2017] [Indexed: 12/21/2022] Open
Abstract
Mitotane (o,p’DDD), the most effective drug in adrenocortical carcinoma, concentrates into the mitochondria and impacts mitochondrial functions. To address the molecular mechanisms of mitotane action and to identify its potential target, metabolomic and lipidomic approaches as well as imaging analyses were employed in human adrenocortical H295R cells allowing identification of Mitochondria-Associated Membranes dysfunction as a critical impact of mitotane. Study of intracellular energetic metabolites by NMR spectroscopy showed that mitotane significantly decreased aspartate while concomitantly increased glutamate content in a time- and concentration-dependent manner. Such alterations were very likely linked to the previously described, mitotane-induced respiratory chain defect. Lipidomic studies of intracellular and intramitochondrial phospholipids revealed that mitotane exposure markedly reduced the phosphatidylserine/phosphatidylethanolamine ratio, indicative of a dysfunction of phosphatidylserine decarboxylase located in Mitochondria-Associated Membranes. Expression levels of Mitochondria-Associated Membranes proteins phosphatidylserine decarboxylase, DRP1, ATAD3A or TSPO were greatly reduced by mitotane as assessed by western blot analyses. Mitotane exposure markedly altered endogenous Mitochondria-Associated Membranes integrity and reduced the magnitude of mitochondria and the endoplasmic reticulum interactions as demonstrated by high resolution deconvolution microscopy and quantification. Finally, we showed that PK11195, a pharmacological inhibitor of the cholesterol translocator TSPO, embedded in Mitochondria-Associated Membranes, exerts a synergetic effect with mitotane in inducing Mitochondria-Associated Membranes disruption, apoptosis and in inhibiting steroid secretion. Altogether, our results demonstrate Mitochondria-Associated Membranes dysfunction in H295R cells treated with mitotane and that TSPO inhibition significantly potentiates mitotane antitumoral and antisecretory actions in vitro. This constitutes a potential and promising pharmacological strategy for patients with adrenocortical carcinoma.
Collapse
|
107
|
Cahill MA, Medlock AE. Thoughts on interactions between PGRMC1 and diverse attested and potential hydrophobic ligands. J Steroid Biochem Mol Biol 2017; 171:11-33. [PMID: 28104494 DOI: 10.1016/j.jsbmb.2016.12.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/21/2016] [Accepted: 12/26/2016] [Indexed: 01/05/2023]
Abstract
Progesterone Receptor Membrane Component 1 (PGRMC1) is located in many different subcellular locations with many different attested and probably location-specific functions. PGRMC1 was recently identified in the mitochondrial outer membrane where it interacts with ferrochelatase, the last enzyme in the heme synthetic pathway. It has been proposed that PGRMC1 may act as a chaperone to shuttle newly synthesized heme from the mitochondrion to cytochrome P450 (cyP450) enzymes. Here we consider potential roles that PGRMC1 may play in transferring heme, and other small hydrophobic ligands such as cholesterol and steroids, between the hydrophobic compartment of the membrane lipid bilayer interior to aqueous proteins, and perhaps to the membranes of other organelles. We review the synthesis and roles of especially PGRMC1- and cyP450-bound heme, the sources and transport of cholesterol, the involvement of PGRMC1 in cholesterol regulation, and the production of the first progestogen pregnenolone from cholesterol. We also show by clustering by inferred models of evolution (CLIME) analysis that PGRMC1 and related proteins exhibit co-evolution with a series of cyP450 enzymes, as well as a group of mitochondrial proteins lacking in several parasitic protist groups. Altogether, PGRMC1 is implicated with important roles in sterol synthesis and energy regulation that are dispensable in certain parasites. Some novel hypothetical models for PGRMC1 function are proposed to direct future investigative research.
Collapse
Affiliation(s)
- Michael A Cahill
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia.
| | - Amy E Medlock
- Department of Biochemistry and Molecular Biology, Augusta University/University of Georgia Medical Partnership, University of Georgia, Athens, GA, 30602-1111, USA
| |
Collapse
|
108
|
Locci A, Pinna G. Neurosteroid biosynthesis down-regulation and changes in GABA A receptor subunit composition: a biomarker axis in stress-induced cognitive and emotional impairment. Br J Pharmacol 2017; 174:3226-3241. [PMID: 28456011 DOI: 10.1111/bph.13843] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/05/2017] [Accepted: 04/12/2017] [Indexed: 12/26/2022] Open
Abstract
By rapidly modulating neuronal excitability, neurosteroids regulate physiological processes, such as responses to stress and development. Excessive stress affects their biosynthesis and causes an imbalance in cognition and emotions. The progesterone derivative, allopregnanolone (Allo) enhances extrasynaptic and postsynaptic inhibition by directly binding at GABAA receptors, and thus, positively and allosterically modulates the function of GABA. Allo levels are decreased in stress-induced psychiatric disorders, including depression and post-traumatic stress disorder (PTSD), and elevating Allo levels may be a valid therapeutic approach to counteract behavioural dysfunction. While benzodiazepines are inefficient, selective serotonin reuptake inhibitors (SSRIs) represent the first choice treatment for depression and PTSD. Their mechanisms to improve behaviour in preclinical studies include neurosteroidogenic effects at low non-serotonergic doses. Unfortunately, half of PTSD and depressed patients are resistant to current prescribed 'high' dosage of these drugs that engage serotonergic mechanisms. Unveiling novel biomarkers to develop more efficient treatment strategies is in high demand. Stress-induced down-regulation of neurosteroid biosynthesis and changes in GABAA receptor subunit expression offer a putative biomarker axis to develop new PTSD treatments. The advantage of stimulating Allo biosynthesis relies on the variety of neurosteroidogenic receptors to be targeted, including TSPO and endocannabinoid receptors. Furthermore, stress favours a GABAA receptor subunit composition with higher sensitivity for Allo. The use of synthetic analogues of Allo is a valuable alternative. Pregnenolone or drugs that stimulate its levels increase Allo but also sulphated steroids, including pregnanolone sulphate which, by inhibiting NMDA tonic neurotransmission, provides neuroprotection and cognitive benefits. In this review, we describe current knowledge on the effects of stress on neurosteroid biosynthesis and GABAA receptor neurotransmission and summarize available pharmacological strategies that by enhancing neurosteroidogenesis are relevant for the treatment of SSRI-resistant patients. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.
Collapse
Affiliation(s)
- Andrea Locci
- The Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Graziano Pinna
- The Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
109
|
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]
|
110
|
Lee J, Yamazaki T, Dong H, Jefcoate C. A single cell level measurement of StAR expression and activity in adrenal cells. Mol Cell Endocrinol 2017; 441:22-30. [PMID: 27521960 PMCID: PMC5896326 DOI: 10.1016/j.mce.2016.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 01/31/2023]
Abstract
The Steroidogenic acute regulatory protein (StAR) directs mitochondrial cholesterol uptake through a C-terminal cholesterol binding domain (CBD) and a 62 amino acid N-terminal regulatory domain (NTD) that contains an import sequence and conserved sites for inner membrane metalloproteases. Deletion of the NTD prevents mitochondrial import while maintaining steroidogenesis but with compromised cholesterol homeostasis. The rapid StAR-mediated cholesterol transfer in adrenal cells depends on concerted mRNA translation, p37 StAR phosphorylation and controlled NTD cleavage. The NTD controls this process with two cAMP-inducible modulators of, respectively, transcription and translation SIK1 and TIS11b/Znf36l1. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA resolves slow RNA splicing at the gene loci in cAMP-induced Y-1 cells and transfer of individual 3.5 kB mRNA molecules to mitochondria. StAR transcription depends on the CREB coactivator CRTC2 and PKA inhibition of the highly inducible suppressor kinase SIK1 and a basal counterpart SIK2. PKA-inducible TIS11b/Znf36l1 binds specifically to highly conserved elements in exon 7 thereby suppressing formation of mRNA and subsequent translation. Co-expression of SIK1, Znf36l1 with 3.5 kB StAR mRNA may limit responses to pulsatile signaling by ACTH while regulating the transition to more prolonged stress.
Collapse
Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Hui Dong
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United States
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States; Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States.
| |
Collapse
|
111
|
Doghman-Bouguerra M, Lalli E. The ER-mitochondria couple: In life and death from steroidogenesis to tumorigenesis. Mol Cell Endocrinol 2017; 441:176-184. [PMID: 27594532 DOI: 10.1016/j.mce.2016.08.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023]
Abstract
Steroidogenesis is a multistep process where interorganelle communications between the endoplasmic reticulum and mitochondria are critical. These intimate interactions physically occur through the Mitochondria-Associated ER membranes called MAMs. MAMs play important roles in mitochondrial morphology and in many cellular functions ranging from lipid metabolism, to calcium signaling and apoptosis together with a critical effect on steroidogenesis. Moreover, our recent characterization of new MAM resident proteins in adrenocortical cells extends the function of MAM in the mechanism of resistance of cancer cells to apoptotic stimuli and offers new perspectives in targeted therapeutic approaches for adrenocortical tumorigenesis.
Collapse
Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France.
| | - Enzo Lalli
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Inserm, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France
| |
Collapse
|
112
|
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.
Collapse
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
| |
Collapse
|
113
|
Kerkhofs M, Giorgi C, Marchi S, Seitaj B, Parys JB, Pinton P, Bultynck G, Bittremieux M. Alterations in Ca 2+ Signalling via ER-Mitochondria Contact Site Remodelling in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:225-254. [PMID: 28815534 DOI: 10.1007/978-981-10-4567-7_17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inter-organellar contact sites establish microdomains for localised Ca2+-signalling events. One of these microdomains is established between the ER and the mitochondria. Importantly, the so-called mitochondria-associated ER membranes (MAMs) contain, besides structural proteins and proteins involved in lipid exchange, several Ca2+-transport systems, mediating efficient Ca2+ transfer from the ER to the mitochondria. These Ca2+ signals critically control several mitochondrial functions, thereby impacting cell metabolism, cell death and survival, proliferation and migration. Hence, the MAMs have emerged as critical signalling hubs in physiology, while their dysregulation is an important factor that drives or at least contributes to oncogenesis and tumour progression. In this book chapter, we will provide an overview of the role of the MAMs in cell function and how alterations in the MAM composition contribute to oncogenic features and behaviours.
Collapse
Affiliation(s)
- Martijn Kerkhofs
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Bruno Seitaj
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Geert Bultynck
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium.
| | - Mart Bittremieux
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| |
Collapse
|
114
|
Arbo BD, Vieira-Marques C, Ruiz-Palmero I, Ortiz-Rodriguez A, Arevalo MA, Garcia-Segura LM, Ribeiro MF. 4'-Chlorodiazepam modulates the development of primary hippocampal neurons in a sex-dependent manner. Neurosci Lett 2016; 639:98-102. [PMID: 28041963 DOI: 10.1016/j.neulet.2016.12.067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/16/2016] [Accepted: 12/27/2016] [Indexed: 12/12/2022]
Abstract
The translocator protein 18kDa (TSPO) is located in the outer mitochondrial membrane and is involved in the cholesterol transport into the mitochondria and in the regulation of steroidogenesis and other mitochondrial functions. It is known that steroid hormones, such as estradiol, testosterone and dihydrotestosterone are neuroprotective and regulate neuritogenesis in the CNS by different mechanisms. However, the developmental effects of TSPO ligands in the CNS are not known. Therefore, the aim of this study was to identify the developmental effects of 4'-chlorodiazepam (4'-CD), a TSPO ligand, in primary cultures of male and female mouse hippocampal neurons. We observed that female neurons showed an advanced neuritogenesis compared to male neurons after 2days in vitro. Moreover, it was shown that 4'-CD administration accelerated the maturation of male hippocampal neurons, without changing the development of female neurons. These findings, showing that 4'-CD modulates the development of hippocampal neurons in a sex-dependent manner, suggest that TSPO may be involved in the regulation of neuritogenesis.
Collapse
Affiliation(s)
- B D Arbo
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil; Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain.
| | - C Vieira-Marques
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil; Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - I Ruiz-Palmero
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - A Ortiz-Rodriguez
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - M A Arevalo
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - L M Garcia-Segura
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - M F Ribeiro
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil
| |
Collapse
|
115
|
Mitsui K, Morimoto N, Niwa T, Yamaura Y, Ohba H, Tsukada H, Katsumata S. Quantification of ONO-2952 Occupancy of 18-kDaTranslocator Protein in Conscious Monkey Brains using Positron Emission Tomography. J Pharmacol Exp Ther 2016; 360:457-465. [DOI: 10.1124/jpet.116.238568] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/15/2016] [Indexed: 12/20/2022] Open
|
116
|
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.
Collapse
Affiliation(s)
- Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville Louisville, KY, USA
| |
Collapse
|
117
|
Venugopal S, Martinez-Arguelles DB, Chebbi S, Hullin-Matsuda F, Kobayashi T, Papadopoulos V. Plasma Membrane Origin of the Steroidogenic Pool of Cholesterol Used in Hormone-induced Acute Steroid Formation in Leydig Cells. J Biol Chem 2016; 291:26109-26125. [PMID: 27815506 DOI: 10.1074/jbc.m116.740928] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 11/03/2016] [Indexed: 02/05/2023] Open
Abstract
Hormone-sensitive acute steroid biosynthesis requires trafficking of cholesterol from intracellular sources to the inner mitochondrial membrane. The precise location of the intracellular cholesterol and its transport mechanism are uncertain. Perfringolysin O, produced by Clostridium perfringens, binds cholesterol. Its fourth domain (D4) retains cholesterol-binding properties but not cytotoxicity. We transfected steroidogenic MA-10 cells of mouse Leydig cell tumors with the mCherry-D4 plasmid. Tagged D4 with fluorescent proteins enabled us to track cholesterol. The staining was primarily localized to the inner leaflet of the plasma membrane and was partially released upon treatment with dibutyryl-cAMP (Bt2cAMP), a cAMP analog. Inhibitors of cholesterol import into mitochondria blocked steroidogenesis and prevented release of D4 (and presumably cholesterol) from the plasma membrane. We conclude that the bulk of the steroidogenic pool of cholesterol, mobilized by Bt2cAMP for acute steroidogenesis, originates from the plasma membrane. Treatment of the cells with steroid metabolites, 22(R)-hydroxycholesterol and pregnenolone, also reduced D4 release from the plasma membrane, perhaps evidence for a feedback effect of elevated steroid formation on cholesterol release. Interestingly, D4 staining was localized to endosomes during Bt2cAMP stimulation suggesting that these organelles are on the route of cholesterol trafficking from the plasma membrane to mitochondria. Finally, D4 was expressed in primary rat Leydig cells with a lentivirus and was released from the plasma membrane following Bt2cAMP treatment. We conclude that the plasma membrane is the source of cholesterol for steroidogenesis in these cells as well as in MA-10 cells.
Collapse
Affiliation(s)
- Sathvika Venugopal
- From the Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, Montreal H4A 3J1, Canada
| | - Daniel Benjamin Martinez-Arguelles
- From the Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, Montreal H4A 3J1, Canada
| | - Seimia Chebbi
- From the Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, Montreal H4A 3J1, Canada
| | - Françoise Hullin-Matsuda
- the Lipid Biology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan.,INSERM U1060, Université Lyon 1, INSA Lyon, 69621 Villeurbanne, France
| | - Toshihide Kobayashi
- the Lipid Biology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan.,INSERM U1060, Université Lyon 1, INSA Lyon, 69621 Villeurbanne, France.,UMR 7213 CNRS, University of Strasbourg, 67401 Illkirch, France, and
| | - Vassilios Papadopoulos
- From the Research Institute of the McGill University Health Centre and the Department of Medicine, McGill University, Montreal H4A 3J1, Canada, .,the Departments of Pharmacology and Therapeutics and.,Biochemistry, McGill University, Montreal H3G 1Y6, Canada
| |
Collapse
|
118
|
Harel T, Yoon WH, Garone C, Gu S, Coban-Akdemir Z, Eldomery MK, Posey JE, Jhangiani SN, Rosenfeld JA, Cho MT, Fox S, Withers M, Brooks SM, Chiang T, Duraine L, Erdin S, Yuan B, Shao Y, Moussallem E, Lamperti C, Donati MA, Smith JD, McLaughlin HM, Eng CM, Walkiewicz M, Xia F, Pippucci T, Magini P, Seri M, Zeviani M, Hirano M, Hunter JV, Srour M, Zanigni S, Lewis RA, Muzny DM, Lotze TE, Boerwinkle E, Gibbs RA, Hickey SE, Graham BH, Yang Y, Buhas D, Martin DM, Potocki L, Graziano C, Bellen HJ, Lupski JR, Bellen HJ, Lupski JR. Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes. Am J Hum Genet 2016; 99:831-845. [PMID: 27640307 DOI: 10.1016/j.ajhg.2016.08.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/04/2016] [Indexed: 12/22/2022] Open
Abstract
ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.Arg528Trp) variant by whole-exome sequencing (WES) in five unrelated individuals with a core phenotype of global developmental delay, hypotonia, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. We also describe two families with biallelic variants in ATAD3A, including a homozygous variant in two siblings, and biallelic ATAD3A deletions mediated by nonallelic homologous recombination (NAHR) between ATAD3A and gene family members ATAD3B and ATAD3C. Tissue-specific overexpression of borR534W, the Drosophila mutation homologous to the human c.1582C>T (p.Arg528Trp) variant, resulted in a dramatic decrease in mitochondrial content, aberrant mitochondrial morphology, and increased autophagy. Homozygous null bor larvae showed a significant decrease of mitochondria, while overexpression of borWT resulted in larger, elongated mitochondria. Finally, fibroblasts of an affected individual exhibited increased mitophagy. We conclude that the p.Arg528Trp variant functions through a dominant-negative mechanism that results in small mitochondria that trigger mitophagy, resulting in a reduction in mitochondrial content. ATAD3A variation represents an additional link between mitochondrial dynamics and recognizable neurological syndromes, as seen with MFN2, OPA1, DNM1L, and STAT2 mutations.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
| |
Collapse
|
119
|
TSPO ligands stimulate ZnPPIX transport and ROS accumulation leading to the inhibition of P. falciparum growth in human blood. Sci Rep 2016; 6:33516. [PMID: 27641616 PMCID: PMC5027585 DOI: 10.1038/srep33516] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 08/30/2016] [Indexed: 11/08/2022] Open
Abstract
After invading red blood cells (RBCs), Plasmodium falciparum (Pf) can export its own proteins to the host membrane and activate endogenous channels that are present in the membrane of RBCs. This transport pathway involves the Voltage Dependent Anion Channel (VDAC). Moreover, ligands of the VDAC partner TranSlocator PrOtein (TSPO) were demonstrated to inhibit the growth of the parasite. We studied the expression of TSPO and VDAC isoforms in late erythroid precursors, examined the presence of these proteins in membranes of non-infected and infected human RBCs, and evaluated the efficiency of TSPO ligands in inhibiting plasmodium growth, transporting the haem analogue Zn-protoporphyrin-IX (ZnPPIX) and enhancing the accumulation of reactive oxygen species (ROS). TSPO and VDAC isoforms are differentially expressed on erythroid cells in late differentiation states. TSPO2 and VDAC are present in the membranes of mature RBCs in a unique protein complex that changes the affinity of TSPO ligands after Pf infection. TSPO ligands dose-dependently inhibited parasite growth, and this inhibition was correlated to ZnPPIX uptake and ROS accumulation in the infected RBCs. Our results demonstrate that TSPO ligands can induce Pf death by increasing the uptake of porphyrins through a TSPO2-VDAC complex, which leads to an accumulation of ROS.
Collapse
|
120
|
Kim T, Pae AN. Translocator protein (TSPO) ligands for the diagnosis or treatment of neurodegenerative diseases: a patent review (2010-2015; part 1). Expert Opin Ther Pat 2016; 26:1325-1351. [PMID: 27607364 DOI: 10.1080/13543776.2016.1230606] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION The translocator protein (TSPO) is an emerging target in diverse neurodegenerative diseases. Up-regulated TSPO in the central nervous system (CNS) appears to be involved in neuroinflammatory processes; therefore, the development of potent TSPO ligands is a promising method for alleviating or imaging patients with neurodegenerative diseases. Areas covered: This review will provide an overview of recently developed TSPO ligands patented from 2010 to 2015. Part 1 will present a summary focusing on TSPO ligands other than indole-based or cholesterol-like compounds, which will be discussed in part 2. Part 1 covers diverse benzodiazepine-derived analogues such as isoquinoline carboxamides and aryloxyanilides. Moreover, bicyclic ring structures such as imidazopyridine, pyrazolopyrimidine, and phenylpurine will be highlighted as promising scaffolds for TSPO ligands. A brief analysis of currently reported TSPO structures will also be covered in part 1. Expert opinion: Although the underlying pharmacological mechanism of TSPO remains to be elucidated, several TSPO ligands have shown therapeutic efficacy in experimental animal models of neurodegenerative diseases. In addition, radioactive TSPO ligands have been extensively studied for the diagnosis of neurodegenerative processes. Thus, further studies on both the basic and applied mechanisms of TSPO are warranted in the pursuit of successful pharmacological applications of TSPO ligands.
Collapse
Affiliation(s)
- TaeHun Kim
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology (KIST) , Seongbuk-Gu , Seoul , Republic of Korea.,b Biological Chemistry , Korea University of Science and Technology , Yuseong-Gu , Daejon , Republic of Korea
| | - Ae Nim Pae
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology (KIST) , Seongbuk-Gu , Seoul , Republic of Korea.,b Biological Chemistry , Korea University of Science and Technology , Yuseong-Gu , Daejon , Republic of Korea
| |
Collapse
|
121
|
Arbo BD, Benetti F, Ribeiro MF. Astrocytes as a target for neuroprotection: Modulation by progesterone and dehydroepiandrosterone. Prog Neurobiol 2016; 144:27-47. [DOI: 10.1016/j.pneurobio.2016.03.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/14/2016] [Accepted: 03/14/2016] [Indexed: 01/19/2023]
|
122
|
Elustondo P, Martin LA, Karten B. Mitochondrial cholesterol import. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:90-101. [PMID: 27565112 DOI: 10.1016/j.bbalip.2016.08.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023]
Abstract
All animal subcellular membranes require cholesterol, which influences membrane fluidity and permeability, fission and fusion processes, and membrane protein function. The distribution of cholesterol among subcellular membranes is highly heterogeneous and the cholesterol content of each membrane must be carefully regulated. Compared to other subcellular membranes, mitochondrial membranes are cholesterol-poor, particularly the inner mitochondrial membrane (IMM). As a result, steroidogenesis can be controlled through the delivery of cholesterol to the IMM, where it is converted to pregnenolone. The low basal levels of cholesterol also make mitochondria sensitive to changes in cholesterol content, which can have a relatively large impact on the biophysical and functional characteristics of mitochondrial membranes. Increased mitochondrial cholesterol levels have been observed in diverse pathological conditions including cancer, steatohepatitis, Alzheimer disease and Niemann-Pick Type C1-deficiency, and are associated with increased oxidative stress, impaired oxidative phosphorylation, and changes in the susceptibility to apoptosis, among other alterations in mitochondrial function. Mitochondria are not included in the vesicular trafficking network; therefore, cholesterol transport to mitochondria is mostly achieved through the activity of lipid transfer proteins at membrane contact sites or by cytosolic, diffusible lipid transfer proteins. Here we will give an overview of the main mechanisms involved in mitochondrial cholesterol import, focusing on the steroidogenic acute regulatory protein StAR/STARD1 and other members of the StAR-related lipid transfer (START) domain protein family, and we will discuss how changes in mitochondrial cholesterol levels can arise and affect mitochondrial function. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Collapse
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.
| |
Collapse
|
123
|
Sarzi E, Seveno M, Angebault C, Milea D, Rönnbäck C, Quilès M, Adrian M, Grenier J, Caignard A, Lacroux A, Lavergne C, Reynier P, Larsen M, Hamel CP, Delettre C, Lenaers G, Müller A. Increased steroidogenesis promotes early-onset and severe vision loss in females with OPA1 dominant optic atrophy. Hum Mol Genet 2016; 25:2539-2551. [PMID: 27260406 DOI: 10.1093/hmg/ddw117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/26/2016] [Accepted: 04/12/2016] [Indexed: 11/13/2022] Open
Abstract
OPA1 mutations are responsible for autosomal dominant optic atrophy (ADOA), a progressive blinding disease characterized by retinal ganglion cell (RGC) degeneration and large phenotypic variations, the underlying mechanisms of which are poorly understood. OPA1 encodes a mitochondrial protein with essential biological functions, its main roles residing in the control of mitochondrial membrane dynamics as a pro-fusion protein and prevention of apoptosis. Considering recent findings showing the importance of the mitochondrial fusion process and the involvement of OPA1 in controlling steroidogenesis, we tested the hypothesis of deregulated steroid production in retina due to a disease-causing OPA1 mutation and its contribution to the visual phenotypic variations. Using the mouse model carrying the human recurrent OPA1 mutation, we disclosed that Opa1 haploinsufficiency leads to very high circulating levels of steroid precursor pregnenolone in females, causing an early-onset vision loss, abolished by ovariectomy. In addition, steroid production in retina is also increased which, in conjunction with high circulating levels, impairs estrogen receptor expression and mitochondrial respiratory complex IV activity, promoting RGC apoptosis in females. We further demonstrate the involvement of Muller glial cells as increased pregnenolone production in female cells is noxious and compromises their role in supporting RGC survival. In parallel, we analyzed ophthalmological data of a multicentre OPA1 patient cohort and found that women undergo more severe visual loss at adolescence and greater progressive thinning of the retinal nerve fibres than males. Thus, we disclosed a gender-dependent effect on ADOA severity, involving for the first time steroids and Müller glial cells, responsible for RGC degeneration.
Collapse
Affiliation(s)
- Emmanuelle Sarzi
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France,
| | - Marie Seveno
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Claire Angebault
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Dan Milea
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France.,Singapore National Eye Centre, Singapore.,Singapore Eye Research Institute, Singapore.,Duke-NUS, Singapore
| | - Cecilia Rönnbäck
- Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melanie Quilès
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Université de Montpellier - Faculté de Pharmacie-Montpellier, France
| | - Mathias Adrian
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France
| | - Joanna Grenier
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Angélique Caignard
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France
| | - Annie Lacroux
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Christian Lavergne
- Institut Montpelliérain Alexander Grothendieck. Université Montpellier 3, France and
| | - Pascal Reynier
- Département de Biochimie et Génétique, UMR CNRS 6214-INSERM 1083, Centre Hospitalier Universitaire, Angers, France
| | - Michael Larsen
- Department of Ophthalmology, Glostrup Hospital, Glostrup, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian P Hamel
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Centre de référence des affections sensorielles d'origine génétique, Hôpital Gui de Chauliac, Montpellier, France
| | - Cécile Delettre
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France,
| | - Guy Lenaers
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,PREMMI, UMR CNRS 6214-INSERM 1083, Université d'Angers, France
| | - Agnès Müller
- INSERM U1051 - Institut des Neurosciences de Montpellier, Montpellier, France.,Université de Montpellier - Faculté de Pharmacie-Montpellier, France
| |
Collapse
|
124
|
Fan J, Li X, Issop L, Culty M, Papadopoulos V. ACBD2/ECI2-Mediated Peroxisome-Mitochondria Interactions in Leydig Cell Steroid Biosynthesis. Mol Endocrinol 2016; 30:763-82. [PMID: 27167610 DOI: 10.1210/me.2016-1008] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Fatty acid metabolism and steroid biosynthesis are 2 major pathways shared by peroxisomes and mitochondria. Both organelles are in close apposition to the endoplasmic reticulum, with which they communicate via interorganelle membrane contact sites to promote cellular signaling and the exchange of ions and lipids. To date, no convincing evidence of the direct contact between peroxisomes and mitochondria was reported in mammalian cells. Hormone-induced, tightly controlled steroid hormone biosynthesis requires interorganelle interactions. Using immunofluorescent staining and live-cell imaging, we found that dibutyryl-cAMP treatment of MA-10 mouse tumor Leydig cells rapidly induces peroxisomes to approach mitochondria and form peroxisome-mitochondrial contact sites/fusion, revealed by the subcellular distribution of the endogenous acyl-coenzyme A-binding domain (ACBD)2/ECI2 isoform A generated by alternative splicing, and further validated using a proximity ligation assay. This event occurs likely via a peroxisome-like structure, which is mediated by peroxisomal and mitochondrial matrix protein import complexes: peroxisomal import receptor peroxisomal biogenesis factor 5 (PEX5), and the mitochondrial import receptor subunit translocase of outer mitochondrial membrane 20 homolog (yeast) protein. Similar results were obtained using the mLTC-1 mouse tumor Leydig cells. Ectopic expression of the ACBD2/ECI2 isoform A in MA-10 cells led to increased basal and hormone-stimulated steroid formation, indicating that ACBD2/ECI2-mediated peroxisomes-mitochondria interactions favor in the exchange of metabolites and/or macromolecules between these 2 organelles in support of steroid biosynthesis. Considering the widespread occurrence of the ACBD2/ECI2 protein, we propose that this protein might serve as a tool to assist in understanding the contact between peroxisomes and mitochondria.
Collapse
Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre (J.F., X.L., L.I., M.C., V.P.) and Departments of Medicine (J.F., L.I., M.C., V.P.), Biochemistry (X.L., V.P.), and Pharmacology and Therapeutics (M.C., V.P.), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Xinlu Li
- The Research Institute of the McGill University Health Centre (J.F., X.L., L.I., M.C., V.P.) and Departments of Medicine (J.F., L.I., M.C., V.P.), Biochemistry (X.L., V.P.), and Pharmacology and Therapeutics (M.C., V.P.), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Leeyah Issop
- The Research Institute of the McGill University Health Centre (J.F., X.L., L.I., M.C., V.P.) and Departments of Medicine (J.F., L.I., M.C., V.P.), Biochemistry (X.L., V.P.), and Pharmacology and Therapeutics (M.C., V.P.), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Martine Culty
- The Research Institute of the McGill University Health Centre (J.F., X.L., L.I., M.C., V.P.) and Departments of Medicine (J.F., L.I., M.C., V.P.), Biochemistry (X.L., V.P.), and Pharmacology and Therapeutics (M.C., V.P.), McGill University, Montréal, Québec, Canada H4A 3J1
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre (J.F., X.L., L.I., M.C., V.P.) and Departments of Medicine (J.F., L.I., M.C., V.P.), Biochemistry (X.L., V.P.), and Pharmacology and Therapeutics (M.C., V.P.), McGill University, Montréal, Québec, Canada H4A 3J1
| |
Collapse
|
125
|
Li F, Liu J, Liu N, Kuhn LA, Garavito RM, Ferguson-Miller S. Translocator Protein 18 kDa (TSPO): An Old Protein with New Functions? Biochemistry 2016; 55:2821-31. [PMID: 27074410 DOI: 10.1021/acs.biochem.6b00142] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translocator protein 18 kDa (TSPO) was previously known as the peripheral benzodiazepine receptor (PBR) in eukaryotes, where it is mainly localized to the mitochondrial outer membrane. Considerable evidence indicates that it plays regulatory roles in steroidogenesis and apoptosis and is involved in various human diseases, such as metastatic cancer, Alzheimer's and Parkinson's disease, inflammation, and anxiety disorders. Ligands of TSPO are widely used as diagnostic tools and treatment options, despite there being no clear understanding of the function of TSPO. An ortholog in the photosynthetic bacterium Rhodobacter was independently discovered as the tryptophan-rich sensory protein (TspO) and found to play a role in the response to changes in oxygen and light conditions that regulate photosynthesis and respiration. As part of this highly conserved protein family found in all three kingdoms, the rat TSPO is able to rescue the knockout phenotype in Rhodobacter, indicating functional as well as structural conservation. Recently, a major breakthrough in the field was achieved: the determination of atomic-resolution structures of TSPO from different species by several independent groups. This now allows us to reexamine the function of TSPO with a molecular perspective. In this review, we focus on recently determined structures of TSPO and their implications for potential functions of this ubiquitous multifaceted protein. We suggest that TSPO is an ancient bacterial receptor/stress sensor that has developed additional interactions, partners, and roles in its mitochondrial outer membrane environment in eukaryotes.
Collapse
Affiliation(s)
- Fei Li
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Nan Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States.,Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - Leslie A Kuhn
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| |
Collapse
|
126
|
Revisiting trends on mitochondrial mega-channels for the import of proteins and nucleic acids. J Bioenerg Biomembr 2016; 49:75-99. [DOI: 10.1007/s10863-016-9662-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/25/2016] [Indexed: 12/14/2022]
|
127
|
Paz C, Cornejo Maciel F, Gorostizaga A, Castillo AF, Mori Sequeiros García MM, Maloberti PM, Orlando UD, Mele PG, Poderoso C, Podesta EJ. Role of Protein Phosphorylation and Tyrosine Phosphatases in the Adrenal Regulation of Steroid Synthesis and Mitochondrial Function. Front Endocrinol (Lausanne) 2016; 7:60. [PMID: 27375556 PMCID: PMC4899475 DOI: 10.3389/fendo.2016.00060] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/25/2016] [Indexed: 12/17/2022] Open
Abstract
In adrenocortical cells, adrenocorticotropin (ACTH) promotes the activation of several protein kinases. The action of these kinases is linked to steroid production, mainly through steroidogenic acute regulatory protein (StAR), whose expression and activity are dependent on protein phosphorylation events at genomic and non-genomic levels. Hormone-dependent mitochondrial dynamics and cell proliferation are functions also associated with protein kinases. On the other hand, protein tyrosine dephosphorylation is an additional component of the ACTH signaling pathway, which involves the "classical" protein tyrosine phosphatases (PTPs), such as Src homology domain (SH) 2-containing PTP (SHP2c), and members of the MAP kinase phosphatase (MKP) family, such as MKP-1. PTPs are rapidly activated by posttranslational mechanisms and participate in hormone-stimulated steroid production. In this process, the SHP2 tyrosine phosphatase plays a crucial role in a mechanism that includes an acyl-CoA synthetase-4 (Acsl4), arachidonic acid (AA) release and StAR induction. In contrast, MKPs in steroidogenic cells have a role in the turn-off of the hormonal signal in ERK-dependent processes such as steroid synthesis and, perhaps, cell proliferation. This review analyzes the participation of these tyrosine phosphates in the ACTH signaling pathway and the action of kinases and phosphatases in the regulation of mitochondrial dynamics and steroid production. In addition, the participation of kinases and phosphatases in the signal cascade triggered by different stimuli in other steroidogenic tissues is also compared to adrenocortical cell/ACTH and discussed.
Collapse
Affiliation(s)
- Cristina Paz
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Fabiana Cornejo Maciel
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Alejandra Gorostizaga
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ana F. Castillo
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - M. Mercedes Mori Sequeiros García
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula M. Maloberti
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ulises D. Orlando
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Pablo G. Mele
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Cecilia Poderoso
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ernesto J. Podesta
- Departamento de Bioquímica Humana, Facultad de Medicina, Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires (UBA-CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- *Correspondence: Ernesto J. Podesta, ,
| |
Collapse
|
128
|
Manna PR, Stetson CL, Slominski AT, Pruitt K. Role of the steroidogenic acute regulatory protein in health and disease. Endocrine 2016; 51:7-21. [PMID: 26271515 PMCID: PMC4707056 DOI: 10.1007/s12020-015-0715-6] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/03/2015] [Indexed: 01/10/2023]
Abstract
Steroid hormones are an important class of regulatory molecules that are synthesized in steroidogenic cells of the adrenal, ovary, testis, placenta, brain, and skin, and influence a spectrum of developmental and physiological processes. The steroidogenic acute regulatory protein (STAR) predominantly mediates the rate-limiting step in steroid biosynthesis, i.e., the transport of the substrate of all steroid hormones, cholesterol, from the outer to the inner mitochondrial membrane. At the inner membrane, cytochrome P450 cholesterol side chain cleavage enzyme cleaves the cholesterol side chain to form the first steroid, pregnenolone, which is converted by a series of enzymes to various steroid hormones in specific tissues. Both basic and clinical evidence have demonstrated the crucial involvement of the STAR protein in the regulation of steroid biosynthesis. Multiple levels of regulation impinge on STAR action. Recent findings demonstrate that hormone-sensitive lipase, through its action on the hydrolysis of cholesteryl esters, plays an important role in regulating STAR expression and steroidogenesis which involve the liver X receptor pathway. Activation of the latter influences macrophage cholesterol efflux that is a key process in the prevention of atherosclerotic cardiovascular disease. Appropriate regulation of steroid hormones is vital for proper functioning of many important biological activities, which are also paramount for geriatric populations to live longer and healthier. This review summarizes the current level of understanding on tissue-specific and hormone-induced regulation of STAR expression and steroidogenesis, and provides insights into a number of cholesterol and/or steroid coupled physiological and pathophysiological consequences.
Collapse
Affiliation(s)
- Pulak R Manna
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA.
| | - Cloyce L Stetson
- Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Andrzej T Slominski
- Department of Dermatology, VA Medical Center, University of Alabama Birmingham, Birmingham, AL, 35294, USA
| | - Kevin Pruitt
- Department of Immunology and Molecular Microbiology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| |
Collapse
|
129
|
Lee J, Tong T, Duan H, Foong YH, Musaitif I, Yamazaki T, Jefcoate C. Regulation of StAR by the N-terminal Domain and Coinduction of SIK1 and TIS11b/Znf36l1 in Single Cells. Front Endocrinol (Lausanne) 2016; 7:107. [PMID: 27531991 PMCID: PMC4969582 DOI: 10.3389/fendo.2016.00107] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/19/2016] [Indexed: 02/01/2023] Open
Abstract
The cholesterol transfer function of steroidogenic acute regulatory protein (StAR) is uniquely integrated into adrenal cells, with mRNA translation and protein kinase A (PKA) phosphorylation occurring at the mitochondrial outer membrane (OMM). The StAR C-terminal cholesterol-binding domain (CBD) initiates mitochondrial intermembrane contacts to rapidly direct cholesterol to Cyp11a1 in the inner membrane (IMM). The conserved StAR N-terminal regulatory domain (NTD) includes a leader sequence targeting the CBD to OMM complexes that initiate cholesterol transfer. Here, we show how the NTD functions to enhance CBD activity delivers more efficiently from StAR mRNA in adrenal cells, and then how two factors hormonally restrain this process. NTD processing at two conserved sequence sites is selectively affected by StAR PKA phosphorylation. The CBD functions as a receptor to stimulate the OMM/IMM contacts that mediate transfer. The NTD controls the transit time that integrates extramitochondrial StAR effects on cholesterol homeostasis with other mitochondrial functions, including ATP generation, inter-organelle fusion, and the major permeability transition pore in partnership with other OMM proteins. PKA also rapidly induces two additional StAR modulators: salt-inducible kinase 1 (SIK1) and Znf36l1/Tis11b. Induced SIK1 attenuates the activity of CRTC2, a key mediator of StAR transcription and splicing, but only as cAMP levels decline. TIS11b inhibits translation and directs the endonuclease-mediated removal of the 3.5-kb StAR mRNA. Removal of either of these functions individually enhances cAMP-mediated induction of StAR. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA reveals asymmetric transcription at the gene locus and slow RNA splicing that delays mRNA formation, potentially to synchronize with cholesterol import. Adrenal cells may retain slow transcription to integrate with intermembrane NTD activation. HR-FISH resolves individual 3.5-kb StAR mRNA molecules via dual hybridization at the 3'- and 5'-ends and reveals an unexpectedly high frequency of 1:1 pairing with mitochondria marked by the matrix StAR protein. This pairing may be central to translation-coupled cholesterol transfer. Altogether, our results show that adrenal cells exhibit high-efficiency StAR activity that needs to integrate rapid cholesterol transfer with homeostasis and pulsatile hormonal stimulation. StAR NBD, the extended 3.5-kb mRNA, SIK1, and Tis11b play important roles.
Collapse
Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
| | - Tiegang Tong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Haichuan Duan
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
| | - Yee Hoon Foong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Ibrahim Musaitif
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA
- *Correspondence: Colin Jefcoate,
| |
Collapse
|
130
|
Midzak A, Papadopoulos V. Adrenal Mitochondria and Steroidogenesis: From Individual Proteins to Functional Protein Assemblies. Front Endocrinol (Lausanne) 2016; 7:106. [PMID: 27524977 PMCID: PMC4965458 DOI: 10.3389/fendo.2016.00106] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022] Open
Abstract
The adrenal cortex is critical for physiological function as the central site of glucocorticoid and mineralocorticoid synthesis. It possesses a great degree of specialized compartmentalization at multiple hierarchical levels, ranging from the tissue down to the molecular levels. In this paper, we discuss this functionalization, beginning with the tissue zonation of the adrenal cortex and how this impacts steroidogenic output. We then discuss the cellular biology of steroidogenesis, placing special emphasis on the mitochondria. Mitochondria are classically known as the "powerhouses of the cell" for their central role in respiratory adenosine triphosphate synthesis, and attention is given to mitochondrial electron transport, in both the context of mitochondrial respiration and mitochondrial steroid metabolism. Building on work demonstrating functional assembly of large protein complexes in respiration, we further review research demonstrating a role for multimeric protein complexes in mitochondrial cholesterol transport, steroidogenesis, and mitochondria-endoplasmic reticulum contact. We aim to highlight with this review the shift in steroidogenic cell biology from a focus on the actions of individual proteins in isolation to the actions of protein assemblies working together to execute cellular functions.
Collapse
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,
| |
Collapse
|
131
|
Arbo BD, Marques CV, Ruiz-Palmero I, Ortiz-Rodriguez A, Ghorbanpoor S, Arevalo MA, Garcia-Segura LM, Ribeiro MF. 4'-Chlorodiazepam is neuroprotective against amyloid-beta through the modulation of survivin and bax protein expression in vitro. Brain Res 2015; 1632:91-7. [PMID: 26707976 DOI: 10.1016/j.brainres.2015.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/06/2015] [Accepted: 12/11/2015] [Indexed: 12/12/2022]
Abstract
The translocator protein of 18kDa (TSPO) is located in the outer mitochondrial membrane and is involved in the cholesterol transport into the mitochondria and in the regulation of steroidogenesis, mitochondrial permeability transition pore opening and apoptosis. TSPO ligands have been investigated as therapeutic agents that promote neuroprotective effects in experimental models of brain injury and neurodegenerative diseases. The aim of this study was to identify the neuroprotective effects of 4'-chlorodiazepam (4'-CD), a ligand of TSPO, against amyloid-beta (Aβ) in SHSY-5Y neuroblastoma cells and its mechanisms of action. Aβ decreased the viability of SHSY-5Y neuroblastoma cells, while 4'-CD had a neuroprotective effect at the doses of 1nM and 10nM. The neuroprotective effects of 4'-CD against Aβ were associated with the inhibition of Aβ-induced upregulation of Bax and downregulation of survivin. In summary, our findings indicate that 4'-CD is neuroprotective against Aβ-induced neurotoxicity by a mechanism that may involve the regulation of Bax and survivin expression.
Collapse
Affiliation(s)
- B D Arbo
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, 90050-170 Porto Alegre, RS, Brazil; Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain.
| | - C V Marques
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, 90050-170 Porto Alegre, RS, Brazil; Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - I Ruiz-Palmero
- Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - A Ortiz-Rodriguez
- Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - S Ghorbanpoor
- Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - M A Arevalo
- Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - L M Garcia-Segura
- Instituto Cajal - CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain
| | - M F Ribeiro
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, 90050-170 Porto Alegre, RS, Brazil
| |
Collapse
|
132
|
Morin D, Musman J, Pons S, Berdeaux A, Ghaleh B. Mitochondrial translocator protein (TSPO): From physiology to cardioprotection. Biochem Pharmacol 2015; 105:1-13. [PMID: 26688086 DOI: 10.1016/j.bcp.2015.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/04/2015] [Indexed: 01/08/2023]
Abstract
The mitochondrial translocator protein (TSPO) is a high affinity cholesterol binding protein which is primarily located in the outer mitochondrial membrane where it has been shown to interact with proteins implicated in mitochondrial permeability transition pore (mPTP) formation. TSPO is found in different species and is expressed at high levels in tissues that synthesize steroids but is also present in other peripheral tissues especially in the heart. TSPO has been involved in the import of cholesterol into mitochondria, a key step in steroidogenesis. This constitutes the main established function of the protein which was recently challenged by genetic studies. TSPO has also been associated directly or indirectly with a wide range of cellular functions such as apoptosis, cell proliferation, differentiation, regulation of mitochondrial function or porphyrin transport. In the heart the role of TSPO remains undefined but a growing body of evidence suggests that TSPO plays a critical role in regulating physiological cardiac function and that TSPO ligands may represent interesting drugs to protect the heart under pathological conditions. This article briefly reviews current knowledge regarding TSPO and discusses its role in the cardiovascular system under physiological and pathologic conditions. More particularly, it provides evidence that TSPO can represent an alternative strategy to develop new pharmacological agents to protect the myocardium against ischemia-reperfusion injury.
Collapse
Affiliation(s)
- Didier Morin
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Julien Musman
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Sandrine Pons
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Alain Berdeaux
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Bijan Ghaleh
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| |
Collapse
|
133
|
Graham A. Mitochondrial regulation of macrophage cholesterol homeostasis. Free Radic Biol Med 2015; 89:982-92. [PMID: 26416507 DOI: 10.1016/j.freeradbiomed.2015.08.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/28/2015] [Accepted: 08/11/2015] [Indexed: 12/19/2022]
Abstract
This review explores the relationship between mitochondrial structure and function in the regulation of macrophage cholesterol metabolism and proposes that mitochondrial dysfunction contributes to loss of the elegant homeostatic mechanisms which normally maintain cellular sterol levels within defined limits. Mitochondrial sterol 27-hydroxylase (CYP27A1) can generate oxysterol activators of liver X receptors which heterodimerise with retinoid X receptors, enhancing the transcription of ATP binding cassette transporters (ABCA1, ABCG1, and ABCG4), that can remove excess cholesterol via efflux to apolipoproteins A-1, E, and high density lipoprotein, and inhibit inflammation. The activity of CYP27A1 is regulated by the rate of supply of cholesterol substrate to the inner mitochondrial membrane, mediated by a complex of proteins. The precise identity of this dynamic complex remains controversial, even in steroidogenic tissues, but may include steroidogenic acute regulatory protein and the 18 kDa translocator protein, together with voltage-dependent anion channels, ATPase AAA domain containing protein 3A, and optic atrophy type 1 proteins. Certainly, overexpression of StAR and TSPO proteins can enhance macrophage cholesterol efflux to apoA-I and/or HDL, while perturbations in mitochondrial function, or changes in the expression of mitochondrial fusion proteins, alter the efficiency of cholesterol efflux. Molecules which can sustain or improve mitochondrial function or increase the activity of the protein complex involved in cholesterol transfer may have utility in resolving the problem of dysregulated macrophage cholesterol homeostasis, a condition which may contribute to inflammation, atherosclerosis, nonalcoholic steatohepatitis, osteoblastic bone resorption, and some disorders of the central nervous system.
Collapse
Affiliation(s)
- Annette Graham
- Department of Life Sciences, School of Health and Life Sciences, and Institute for Applied Health Research, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow G4 0BA, United Kingdom.
| |
Collapse
|
134
|
|
135
|
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.
Collapse
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
| |
Collapse
|
136
|
Culty M, Liu Y, Manku G, Chan WY, Papadopoulos V. Expression of steroidogenesis-related genes in murine male germ cells. Steroids 2015; 103:105-14. [PMID: 26302977 DOI: 10.1016/j.steroids.2015.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 07/14/2015] [Accepted: 08/17/2015] [Indexed: 12/22/2022]
Abstract
For decades, only few tissues and cell types were defined as steroidogenic, capable of de novo steroid synthesis from cholesterol. However, with the refinement of detection methods, several tissues have now been added to the list of steroidogenic tissues. Besides their critical role as long-range acting hormones, steroids are also playing more discreet roles as local mediators and signaling molecules within the tissues they are produced. In testis, steroidogenesis is carried out by the Leydig cells through a broad network of proteins, mediating cholesterol delivery to CYP11A1, the first cytochrome of the steroidogenic cascade, and the sequential action of enzymes insuring the production of active steroids, the main one being testosterone. The knowledge that male germ cells can be directly regulated by steroids and that they express several steroidogenesis-related proteins led us to hypothesize that germ cells could produce steroids, acting as autocrine, intracrine and juxtacrine modulators, as a way to insure synchronized progression within spermatogenic cycles, and preventing inappropriate cell behaviors between neighboring cells. Gene expression and protein analyses of mouse and rat germ cells from neonatal gonocytes to spermatozoa showed that most steroidogenesis-associated genes are expressed in germ cells, showing cell type-, spermatogenic cycle-, and age-specific expression profiles. Highly expressed genes included genes involved in steroidogenesis and other cell functions, such as Acbd1 and 3, Tspo and Vdac1-3, and genes involved in fatty acids metabolism or synthesis, including Hsb17b4 10 and 12, implying broader roles than steroid synthesis in germ cells. These results support the possibility of an additional level of regulation of spermatogenesis exerted between adjacent germ cells.
Collapse
Affiliation(s)
- Martine Culty
- The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
| | - Ying Liu
- Section of Experimental Atherosclerosis, Center of Molecular Medicine, NHLBI, NIH, Bethesda, MD, USA
| | - Gurpreet Manku
- The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Wai-Yee Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
| |
Collapse
|
137
|
Arbo BD, Benetti F, Garcia-Segura LM, Ribeiro MF. Therapeutic actions of translocator protein (18 kDa) ligands in experimental models of psychiatric disorders and neurodegenerative diseases. J Steroid Biochem Mol Biol 2015. [PMID: 26200949 DOI: 10.1016/j.jsbmb.2015.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Translocator protein (TSPO) is an 18kDa protein located at contact sites between the outer and the inner mitochondrial membrane. Numerous studies have associated TSPO with the translocation of cholesterol across the aqueous mitochondrial intermembrane space and the regulation of steroidogenesis, as well as with the control of some other mitochondrial functions, such as mitochondrial respiration, mitochondrial permeability transition pore opening, apoptosis and cell proliferation. In the brain, changes in TSPO expression occur in several neuropathological conditions including neurodegenerative diseases and psychiatric disorders. Furthermore, TSPO ligands have been shown to promote neuroprotection in animal models of brain pathology. At least in some cases, the mechanisms of neuroprotection are associated with modifications in brain steroidogenesis. In addition, regulation of neuroinflammation seems to be a common mechanism in the neuroprotective actions of TSPO ligands in different animal models of brain pathology.
Collapse
Affiliation(s)
- B D Arbo
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil; Cajal Institute, CSIC, Avenida Doctor Arce, 37, 28002 Madrid, Spain.
| | - F Benetti
- Laboratório de Neurofisiologia Cognitiva e do Desenvolvimento, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil
| | | | - M F Ribeiro
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500, CEP 90050-170 Porto Alegre, RS, Brazil
| |
Collapse
|
138
|
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.
Collapse
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
| |
Collapse
|
139
|
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.
Collapse
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.
| |
Collapse
|
140
|
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.
Collapse
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.
| |
Collapse
|
141
|
Gak IA, Radovic SM, Dukic AR, Janjic MM, Stojkov-Mimic NJ, Kostic TS, Andric SA. Stress triggers mitochondrial biogenesis to preserve steroidogenesis in Leydig cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2217-27. [PMID: 26036344 DOI: 10.1016/j.bbamcr.2015.05.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/25/2015] [Accepted: 05/29/2015] [Indexed: 12/12/2022]
Abstract
Adaptability to stress is a fundamental prerequisite for survival. Mitochondria are a key component of the stress response in all cells. For steroid-hormones-producing cells, including also Leydig cells of testes, the mitochondria are a key control point for the steroid biosynthesis and regulation. However, the mitochondrial biogenesis in steroidogenic cells has never been explored. Here we show that increased mitochondrial biogenesis is the adaptive response of testosterone-producing Leydig cells from stressed rats. All markers of mitochondrial biogenesis together with transcription factors and related kinases are up-regulated in Leydig cells from rats exposed to repeated psychophysical stress. This is followed with increased mitochondrial mass. The expression of PGC1, master regulator of mitochondrial biogenesis and integrator of environmental signals, is stimulated by cAMP-PRKA, cGMP, and β-adrenergic receptors. Accordingly, stress-triggered mitochondrial biogenesis represents an adaptive mechanism and does not only correlate with but also is an essential for testosterone production, being both events depend on the same regulators. Here we propose that all events induced by acute stress, the most common stress in human society, provoke adaptive response of testosterone-producing Leydig cells and activate PGC1, a protein required to make new mitochondria but also protector against the oxidative damage. Given the importance of mitochondria for steroid hormones production and stress response, as well as the role of steroid hormones in stress response and metabolic syndrome, we anticipate our result to be a starting point for more investigations since stress is a constant factor in life and has become one of the most significant health problems in modern societies.
Collapse
Affiliation(s)
- Igor A Gak
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Sava M Radovic
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Aleksandra R Dukic
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Marija M Janjic
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Natasa J Stojkov-Mimic
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Tatjana S Kostic
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia
| | - Silvana A Andric
- Laboratory for Reproductive Endocrinology and Signaling (LaRES), Faculty of Sciences, University of Novi Sad, Dositeja Obradovica Sq. 2, 21000 Novi Sad, Serbia.
| |
Collapse
|
142
|
Conditional steroidogenic cell-targeted deletion of TSPO unveils a crucial role in viability and hormone-dependent steroid formation. Proc Natl Acad Sci U S A 2015; 112:7261-6. [PMID: 26039990 DOI: 10.1073/pnas.1502670112] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Translocator protein (TSPO) is a key member of the mitochondrial cholesterol transport complex in steroidogenic tissues. To assess the function of TSPO, we generated two lines of Cre-mediated Tspo conditional knockout (cKO) mice. First, gonadal somatic cell-targeting Amhr2-Cre mice were crossed with Tspo-floxed mice to obtain F1 Tspo Amhr2 cKO mice (Tspo(fl/fl);Amhr2-Cre(/+)). The unexpected Mendelian ratio of 4.4% cKO mice was confirmed by genotyping of 12.5-day-postcoitum (dpc) embryos. As Amhr2-Cre is expressed in gonads at 12.5 dpc, these findings suggest preimplantation selection of embryos. Analysis of expression databases revealed elevated levels of Amhr2 in two- and eight-cell zygotes, suggesting ectopic Tspo silencing before the morula stage and demonstrating elevated embryonic lethality and involvement of TSPO in embryonic development. To circumvent this issue, steroidogenic cell-targeting Nr5a1-Cre mice were crossed with Tspo-floxed mice. The resulting Tspo(fl/fl);Nr5a1-Cre(/+) mice were born at a normal Mendelian ratio. Nr5a1-driven Tspo cKO mice exhibited highly reduced Tspo levels in adrenal cortex and gonads. Treatment of mice with human chorionic gonadotropin (hCG) resulted in increased circulating testosterone levels despite extensive lipid droplet depletion. In contrast, Nr5a1-driven Tspo cKO mice lost their ability to form corticosterone in response to adrenocorticotropic hormone (ACTH). Important for ACTH-dependent steroidogenesis, Mc2r, Stard1, and Cypa11a1 levels were unaffected, whereas Scarb1 levels were increased and accumulation of lipid droplets was observed, indicative of a blockade of cholesterol utilization for steroidogenesis. TSPO expression in the adrenal medulla and increased epinephrine production were also observed. In conclusion, TSPO was found necessary for preimplantation embryo development and ACTH-stimulated steroid biosynthesis.
Collapse
|
143
|
Graham A, Allen AM. Mitochondrial function and regulation of macrophage sterol metabolism and inflammatory responses. World J Cardiol 2015; 7:277-286. [PMID: 26015858 PMCID: PMC4438467 DOI: 10.4330/wjc.v7.i5.277] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/25/2015] [Accepted: 03/18/2015] [Indexed: 02/06/2023] Open
Abstract
The aim of this review is to explore the role of mitochondria in regulating macrophage sterol homeostasis and inflammatory responses within the aetiology of atherosclerosis. Macrophage generation of oxysterol activators of liver X receptors (LXRs), via sterol 27-hydroxylase, is regulated by the rate of flux of cholesterol to the inner mitochondrial membrane, via a complex of cholesterol trafficking proteins. Oxysterols are key signalling molecules, regulating the transcriptional activity of LXRs which coordinate macrophage sterol metabolism and cytokine production, key features influencing the impact of these cells within atherosclerotic lesions. The precise identity of the complex of proteins mediating mitochondrial cholesterol trafficking in macrophages remains a matter of debate, but may include steroidogenic acute regulatory protein and translocator protein. There is clear evidence that targeting either of these proteins enhances removal of cholesterol via LXRα-dependent induction of ATP binding cassette transporters (ABCA1, ABCG1) and limits the production of inflammatory cytokines; interventions which influence mitochondrial structure and bioenergetics also impact on removal of cholesterol from macrophages. Thus, molecules which can sustain or improve mitochondrial structure, the function of the electron transport chain, or increase the activity of components of the protein complex involved in cholesterol transfer, may therefore have utility in limiting or regressing atheroma development, reducing the incidence of coronary heart disease and myocardial infarction.
Collapse
|
144
|
Bjelic MM, Stojkov NJ, Radovic SM, Baburski AZ, Janjic MM, Kostic TS, Andric SA. Prolonged in vivo administration of testosterone-enanthate, the widely used and abused anabolic androgenic steroid, disturbs prolactin and cAMP signaling in Leydig cells of adult rats. J Steroid Biochem Mol Biol 2015; 149:58-69. [PMID: 25603467 DOI: 10.1016/j.jsbmb.2015.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/20/2014] [Accepted: 01/14/2015] [Indexed: 12/14/2022]
Abstract
This study was designed to systematically analyze and define the effects of 1-day, 2-weeks, 10-weeks intramuscular administration of testosterone-enanthate, widely used and abused anabolic androgenic steroid (AAS), on main regulators of steroidogenesis and steroidogenic genes expression in testosterone-producing Leydig cells of adult rats. The results showed that prolonged (10-weeks) intramuscular administration of testosterone-enanthate, in clinically relevant dose, significantly increased prolactin, but decreased Prlr2 and Gnrhr in pituitary of adult rat. The levels of testosterone, Insl3, cAMP and mitochondrial membrane potential of Leydig cells were significantly reduced. This was followed by decreased expression of some steroidogenic enzymes and regulatory proteins such as Lhcgr, Prlr1/2, Tspo, Star, Cyp11a1, Cyp17a1, Dax1. Oppositely, Hsd3b1/2, Hsd3b5, Hsd17b4, Ar, Arr19 increased. In the same cells, transcriptional milieu of cAMP signaling elements was disturbed with remarkable up-regulation of PRKA (the main regulator of steroidogenesis). Increased prolactin together with stimulated transcription of Jak2/Jak3 could account for increased Hsd3b1/2 and Hsd3b5 in Leydig cells following 10-weeks in vivo treatment with testosterone-enanthate. In vitro studies revealed that testosterone is capable to increase level of Prlr1, Prlr2, Hsd3b1/2, Hsd3b5 in Leydig cells. Accordingly, testosterone-induced changes in prolactin receptor signaling together with up-regulation of PRKA, Hsd3b1/2, Hsd3b5, Ar in Leydig cells, could be the possible mechanism that contribute to the establishment of a new adaptive response to maintain homeostasis and prevent loss of steroidogenic function. Presented data provide new molecular insights into the relationship between disturbed testosterone homeostasis and mammalian reproduction and are important in terms of wide use and abuse of AASs and human reproductive health.
Collapse
Affiliation(s)
- Maja M Bjelic
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Natasa J Stojkov
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Sava M Radovic
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Aleksandar Z Baburski
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Marija M Janjic
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Tatjana S Kostic
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Silvana A Andric
- Reproductive Endocrinology and Signaling Group, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia.
| |
Collapse
|
145
|
Midzak AS, Akula N, Rone MB, Papadopoulos V. Computational modeling and biological validation of novel non-steroidal ligands for the cholesterol recognition/interaction amino acid consensus (CRAC) motif of the mitochondrial translocator protein (TSPO). Pharmacol Res 2015; 99:393-403. [PMID: 25936508 DOI: 10.1016/j.phrs.2015.03.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 03/27/2015] [Accepted: 03/27/2015] [Indexed: 01/24/2023]
Abstract
Mitochondria play a critical role in the physiological homeostasis of the cell, contributing to numerous cellular processes, including bioenergetics, metabolism and cell life and death. Owing to their keystone role, mitochondria have gained much attention as pharmacological targets. The outer mitochondrial integral membrane translocator protein (TSPO) has attracted a significant degree of pharmacological interest owing to its ability to bind a number of classes of drugs with high affinity and specificity. In addition to its well-characterized drug binding site, TSPO possess an additional high-affinity ligand binding site, originally identified for its ability to bind the lipid cholesterol, which was named the cholesterol recognition/interaction amino acid consensus (CRAC) motif. Previous investigations from our laboratory identified additional ligands targeted to TSPO's CRAC motif which are able to potently inhibit mitochondrial cholesterol transport and steroid biosynthesis, processes for which TSPO has been well-characterized. However, all of these compounds possessed the steroidal backbone common to cholesterol and steroid hormones. In our efforts to expand our understanding of TSPO's CRAC motif, we performed studies aimed at identifying non-steroidal ligands for this motif. Molecular modeling and in silico screening of large chemical libraries identified a panel of compounds which were subsequently screened for bioactivity in a number of steroidogenic model systems. These efforts identified a family of non-steroidal CRAC ligands able to potently inhibit steroidogenesis, and at higher concentrations, promote apoptosis. In addition, the best candidate in this family was able to suppress testosterone synthesis when administered to rats, indicating that this novel family of non-steroidal CRAC ligands may serve as prototypes for the development of drugs useful for treatment of diseases of steroid overproduction, such as Cushing's syndrome and steroidogenic cell tumors in humans and animals.
Collapse
Affiliation(s)
- Andrew S Midzak
- The Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Nagaraju Akula
- The Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Malena B Rone
- The Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre and Department of Medicine, McGill University, Montreal, Quebec, Canada; Departments of Biochemistry and Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
| |
Collapse
|
146
|
Li F, Liu J, Garavito RM, Ferguson-Miller S. Evolving understanding of translocator protein 18 kDa (TSPO). Pharmacol Res 2015; 99:404-9. [PMID: 25882248 DOI: 10.1016/j.phrs.2015.03.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 02/01/2023]
Abstract
The translocator protein 18 kDa (TSPO) has been the focus of intense research by the biomedical community and the pharmaceutical industry because of its apparent involvement in many disease-related processes. These include steroidogenesis, apoptosis, inflammation, neurological disease and cancer, resulting in the use of TSPO as a biomarker and its potential as a drug target. Despite more than 30 years of study, the precise function of TSPO remains elusive. A recent breakthrough in determining the high-resolution crystal structures of bacterial homologs of mitochondrial TSPO provides new insight into the structural and functional properties at a molecular level and new opportunities for investigating the significance of this ancient and highly conserved protein family. The availability of atomic level structural information from different species also provides a platform for structure-based drug development. Here we briefly review current knowledge regarding TSPO and the implications of the new structures with respect to hypotheses and controversies in the field.
Collapse
Affiliation(s)
- Fei Li
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - R Michael Garavito
- Department of Biochemistry and Molecular Biology, 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.
| |
Collapse
|
147
|
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.
Collapse
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.
| |
Collapse
|
148
|
Mitochondrial cholesterol: mechanisms of import and effects on mitochondrial function. J Bioenerg Biomembr 2014; 48:137-51. [PMID: 25425472 DOI: 10.1007/s10863-014-9592-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/14/2014] [Indexed: 12/23/2022]
Abstract
Mitochondria require cholesterol for biogenesis and membrane maintenance, and for the synthesis of steroids, oxysterols and hepatic bile acids. Multiple pathways mediate the transport of cholesterol from different subcellular pools to mitochondria. In steroidogenic cells, the steroidogenic acute regulatory protein (StAR) interacts with a mitochondrial protein complex to mediate cholesterol delivery to the inner mitochondrial membrane for conversion to pregnenolone. In non-steroidogenic cells, several members of a protein family defined by the presence of a StAR-related lipid transfer (START) domain play key roles in the delivery of cholesterol to mitochondrial membranes. Subdomains of the endoplasmic reticulum (ER), termed mitochondria-associated ER membranes (MAM), form membrane contact sites with mitochondria and may contribute to the transport of ER cholesterol to mitochondria, either independently or in conjunction with lipid-transfer proteins. Model systems of mitochondria enriched with cholesterol in vitro and mitochondria isolated from cells with (patho)physiological mitochondrial cholesterol accumulation clearly demonstrate that mitochondrial cholesterol levels affect mitochondrial function. Increased mitochondrial cholesterol levels have been observed in several diseases, including cancer, ischemia, steatohepatitis and neurodegenerative diseases, and influence disease pathology. Hence, a deeper understanding of the mechanisms maintaining mitochondrial cholesterol homeostasis may reveal additional targets for therapeutic intervention. Here we give a brief overview of mitochondrial cholesterol import in steroidogenic cells, and then focus on cholesterol trafficking pathways that deliver cholesterol to mitochondrial membranes in non-steroidogenic cells. We also briefly discuss the consequences of increased mitochondrial cholesterol levels on mitochondrial function and their potential role in disease pathology.
Collapse
|
149
|
Leneveu-Jenvrin C, Connil N, Bouffartigues E, Papadopoulos V, Feuilloley MGJ, Chevalier S. Structure-to-function relationships of bacterial translocator protein (TSPO): a focus on Pseudomonas. Front Microbiol 2014; 5:631. [PMID: 25477872 PMCID: PMC4237140 DOI: 10.3389/fmicb.2014.00631] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 11/04/2014] [Indexed: 12/21/2022] Open
Abstract
The translocator protein (TSPO), which was previously designated as the peripheral-type benzodiazepine receptor, is a 3.5 billion year-old evolutionarily conserved protein expressed by most Eukarya, Archae and Bacteria, but its organization and functions differ remarkably. By taking advantage of the genomic data available on TSPO, we focused on bacterial TSPO and attempted to define functions of TSPO in Pseudomonas via in silico approaches. A tspo ortholog has been identified in several fluorescent Pseudomonas. This protein presents putative binding motifs for cholesterol and PK 11195, which is a specific drug ligand of mitochondrial TSPO. While it is a common surface distribution, the sense of insertion and membrane localization differ between α- and γ-proteobacteria. Experimental published data and STRING analysis of common TSPO partners in fluorescent Pseudomonas indicate a potential role of TSPO in the oxidative stress response, iron homeostasis and virulence expression. In these bacteria, TSPO could also take part in signal transduction and in the preservation of membrane integrity.
Collapse
Affiliation(s)
- Charlène Leneveu-Jenvrin
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Nathalie Connil
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Vassilios Papadopoulos
- Department of Medicine, Research Institute of the McGill University Health Centre, McGill University Montreal, QC, Canada
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| |
Collapse
|
150
|
Martel C, Wang Z, Brenner C. VDAC phosphorylation, a lipid sensor influencing the cell fate. Mitochondrion 2014; 19 Pt A:69-77. [DOI: 10.1016/j.mito.2014.07.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/17/2014] [Accepted: 07/22/2014] [Indexed: 12/21/2022]
|