1
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Giladi M, Montgomery AP, Kassiou M, Danon JJ. Structure-based drug design for TSPO: Challenges and opportunities. Biochimie 2024:S0300-9084(24)00120-2. [PMID: 38782353 DOI: 10.1016/j.biochi.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/27/2024] [Accepted: 05/21/2024] [Indexed: 05/25/2024]
Abstract
The translocator protein 18 kDa (TSPO) is an evolutionarily conserved mitochondrial transmembrane protein implicated in various neuropathologies and inflammatory conditions, making it a longstanding diagnostic and therapeutic target of interest. Despite the development of various classes of TSPO ligand chemotypes, and the elucidation of bacterial and non-human mammalian experimental structures, many unknowns exist surrounding its differential structural and functional features in health and disease. There are several limitations associated with currently used computational methodologies for modelling the native structure and ligand-binding behaviour of this enigmatic protein. In this perspective, we provide a critical analysis of the developments in the uses of these methods, outlining their uses, inherent limitations, and continuing challenges. We offer suggestions of unexplored opportunities that exist in the use of computational methodologies which offer promise for enhancing our understanding of the TSPO.
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Affiliation(s)
- Mia Giladi
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia
| | | | - Michael Kassiou
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
| | - Jonathan J Danon
- School of Chemistry, The University of Sydney, 2050, Sydney, NSW, Australia.
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2
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Trudel G, Stratis D, Rocheleau L, Pelchat M, Laneuville O. Transcriptomic evidence of erythropoietic adaptation from the International Space Station and from an Earth-based space analog. NPJ Microgravity 2024; 10:55. [PMID: 38740795 DOI: 10.1038/s41526-024-00400-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024] Open
Abstract
Space anemia affects astronauts and the underlying molecular alterations remain unknown. We evaluated the response of erythropoiesis-modulating genes to spaceflight through the analysis of leukocyte transcriptomes from astronauts during long-duration spaceflight and from an Earth model of microgravity. Differential expression analysis identified 50 genes encoding ribosomal proteins with reduced expression at the transition to bed rest and increased during the bed rest phase; a similar trend was observed in astronauts. Additional genes associated with anemia (15 genes), erythrocyte maturation (3 genes), and hemoglobin (6 genes) were down-regulated during bed rest and increased during reambulation. Transcript levels of the erythropoiesis transcription factor GATA1 and nine of most enriched erythrocyte proteins increased at reambulation after bed rest and at return to Earth from space. Dynamic changes of the leukocyte transcriptome composition while in microgravity and during reambulation supported an erythropoietic modulation accompanying the hemolysis of space anemia and of immobility-induced anemia.
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Affiliation(s)
- Guy Trudel
- Bone and Joint Research Laboratory, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada.
- Department of Medicine, Division of Physiatry, Faculty of Medicine, University of Ottawa, 505 Smyth Road, Ottawa, ON, K1H 8M2, Canada.
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
| | - Daniel Stratis
- Department of Biology, Faculty of Science, University of Ottawa, 30 Marie Curie Private Drive, Ottawa, ON, K1N 6N5, Canada.
| | - Lynda Rocheleau
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
| | - Odette Laneuville
- Bone and Joint Research Laboratory, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, K1H 8L6, Canada.
- Department of Biology, Faculty of Science, University of Ottawa, 30 Marie Curie Private Drive, Ottawa, ON, K1N 6N5, Canada.
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3
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Hector M, Langmann T, Wolf A. Translocator protein (18 kDa) (Tspo) in the retina and implications for ocular diseases. Prog Retin Eye Res 2024; 100:101249. [PMID: 38430990 DOI: 10.1016/j.preteyeres.2024.101249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
Translocator protein (18 kDa) (Tspo), formerly known as peripheral benzodiazepine receptor is a highly conserved transmembrane protein primarily located in the outer mitochondrial membrane. In the central nervous system (CNS), especially in glia cells, Tspo is upregulated upon inflammation. Consequently, Tspo was used as a tool for diagnostic in vivo imaging of neuroinflammation in the brain and as a potential therapeutic target. Several synthetic Tspo ligands have been explored as immunomodulatory and neuroprotective therapy approaches. Although the function of Tspo and how its ligands exert these beneficial effects is not fully clear, it became a research topic of interest, especially in ocular diseases in the past few years. This review summarizes state-of-the-art knowledge of Tspo expression and its proposed functions in different cells of the retina including microglia, retinal pigment epithelium and Müller cells. Tspo is involved in cytokine signaling, oxidative stress and reactive oxygen species production, calcium signaling, neurosteroid synthesis, energy metabolism, and cholesterol efflux. We also highlight recent developments in preclinical models targeting Tspo and summarize the relevance of Tspo biology for ocular and retinal diseases. We conclude that glial upregulation of Tspo in different ocular pathologies and the use of Tspo ligands as promising therapeutic approaches in preclinical studies underline the importance of Tspo as a potential disease-modifying protein.
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Affiliation(s)
- Mandy Hector
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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4
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Rao RM, El Dhaybi I, Cadet F, Etchebest C, Diharce J. The mutual and dynamic role of TSPO and ligands in their binding process: An example with PK-11195. Biochimie 2024:S0300-9084(24)00067-1. [PMID: 38494108 DOI: 10.1016/j.biochi.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/12/2024] [Accepted: 03/15/2024] [Indexed: 03/19/2024]
Abstract
Translocator protein (TSPO) is an 18 kDa transmembrane protein, localized primarily on the outer mitochondrial membrane. It has been found to be involved in various physiological processes and pathophysiological conditions. Though studies on its structure have been performed only recently, there is little information on the nature of dynamics and doubts about some structures referenced in the literature, especially the NMR structure of mouse TSPO. In the present work, we thoroughly study the dynamics of mouse TSPO protein by means of atomistic molecular dynamics simulations, in presence as well as in absence of the diagnostic ligand PKA. We considered two starting structures: the NMR structure and a homology model (HM) generated on the basis of X-ray structures from bacterial TSPO. We examine the conformational landscape in both the modes for both starting points, in presence and absence of the ligand, in order to measure its impact for both structures. The analysis highlights high flexibility of the protein globally, but NMR simulations show a surprisingly flexibility even in the presence of the ligand. Interestingly, this is not the case for HM calculations, to the point that the ligand seems not so stable as in the NMR system and an unbinding event process is partially sampled. All those results tend to show that the NMR structure of mTSPO seems not deficient but is just in another portion of the global conformation space of TSPO.
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Affiliation(s)
- Rajas M Rao
- Data Analytics, Bioinformatics and Structural Biology Division, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India; Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB UMR_S1134, F-74014, Paris, France
| | - Ibaa El Dhaybi
- Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB UMR_S1134, F-74014, Paris, France
| | - Frédéric Cadet
- Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB UMR_S1134, F-74014, Paris, France; Laboratory of Excellence GR-Ex, Paris, France; Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB, F-97715, Saint Denis Messag, France; PEACCEL, Artificial Intelligence Department, Paris, 75013 France
| | - Catherine Etchebest
- Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB UMR_S1134, F-74014, Paris, France; Laboratory of Excellence GR-Ex, Paris, France
| | - Julien Diharce
- Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB UMR_S1134, F-74014, Paris, France; Laboratory of Excellence GR-Ex, Paris, France.
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5
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Duport C, Armengaud J, Schmitt C, Morin D, Lacapère JJ. Elucidating the pivotal role of TSPO in porphyrin-related cellular processes, in Bacillus cereus. Biochimie 2024:S0300-9084(24)00046-4. [PMID: 38423451 DOI: 10.1016/j.biochi.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
A structural homolog of the mammalian TSPO has been identified in the human pathogen Bacillus cereus. BcTSPO, in its recombinant form, has previously been shown to bind and degrade porphyrins. In this study, we generated a ΔtspO mutant strain in B. cereus ATCC 14579 and assessed the impact of the absence of BcTSPO on cellular proteomics and physiological characteristics. The proteomic analysis revealed correlations between the lack of BcTSPO and the observed growth defects, increased oxygen consumption, ATP deficiency, heightened tryptophan catabolism, reduced motility, and impaired biofilm formation in the ΔtspO mutant strain. Our results also suggested that BcTSPO plays a crucial role in regulating intracellular levels of metabolites from the coproporphyrin-dependent branch of the heme biosynthetic pathway. This regulation potentially underlies alterations in the metabolic landscape, emphasizing the pivotal role of BcTSPO in B. cereus aerobic metabolism. Notably, our study unveils, for the first time, the involvement of TSPO in tryptophan metabolism. These findings underscore the multifaceted role of TSPO, not only in metabolic pathways but also potentially in the microorganism's virulence mechanisms.
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Affiliation(s)
| | - Jean Armengaud
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200, Bagnols-sur-Cèze, France
| | - Caroline Schmitt
- Assistance Publique Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, 92700, Colombes, France; INSERM U1149, Center for Research on Inflammation (CRI), Université de Paris, 75018, Paris, France
| | - Didier Morin
- INSERM, U955, équipe 3, Faculté de Médecine, Université Paris Est, 94010, Creteil, France
| | - Jean-Jacques Lacapère
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS UMR 7203, Laboratoire des BioMolécules (LBM), 4 place Jussieu, F-75005, Paris, France
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6
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Corsi F, Baglini E, Barresi E, Salerno S, Cerri C, Martini C, Da Settimo Passetti F, Taliani S, Gargini C, Piano I. Targeting TSPO Reduces Inflammation and Apoptosis in an In Vitro Photoreceptor-Like Model of Retinal Degeneration. ACS Chem Neurosci 2022; 13:3188-3197. [PMID: 36300862 PMCID: PMC9673150 DOI: 10.1021/acschemneuro.2c00582] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The 18 kDa translocator protein (TSPO) is predominantly located in the mitochondrial outer membrane, playing an important role in steroidogenesis, inflammation, survival, and cell proliferation. Its expression in the CNS, and mainly in glial cells, is upregulated in neuropathologies and brain injury. In this study, the potential of targeting TSPO for the therapeutic treatment of inflammatory-based retinal neurodegeneration was evaluated by means of an in vitro model of lipopolysaccharide (LPS)-induced degeneration in 661 W cells, a photoreceptor-like cell line. After the assessment of the expression of TSPO in 661W cells, which, to the best of our knowledge, was never investigated so far, the anti-inflammatory and cytoprotective effects of a number of known TSPO ligands, belonging to the class of N,N-dialkyl-2-arylindol-3-ylglyoxylamides (PIGAs), were evaluated, using the classic TSPO ligand PK11195 as the reference standard. All tested PIGAs showed the ability to modulate the inflammatory and apoptotic processes in 661 W photoreceptor-like cells and to reduce LPS-driven cellular cytotoxicity. The protective effect of PIGAs was, in all cases, reduced by cotreatment with the pregnenolone synthesis inhibitor SU-10603, suggesting the involvement of neurosteroids in the protective mechanism. As inflammatory processes play a crucial role in the retinal neurodegenerative disease progression toward photoreceptors' death and complete blindness, targeting TSPO might represent a successful strategy to slow down this degenerative process that may lead to the inexorable loss of vision.
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7
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Amante C, Esposito T, Luccheo G, Luccheo L, Russo P, Del Gaudio P. Recapsoma®: A Novel Mixture Based on Bergamot, Ipomoea Batatas, Policosanol Extracts and Liposomal Berberine for the Treatment of Hypercholesterolemia. Life (Basel) 2022; 12:life12081162. [PMID: 36013341 PMCID: PMC9409730 DOI: 10.3390/life12081162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Cardiovascular disease (CVD) is considered one of the major causes of mortality worldwide. Epidemiological studies have shown that regular consumption of phenols is inversely associated with cardiovascular disease, and the use of nutraceuticals and functional foods can provide protective, preventive, and possibly curative effects in CVD. A novel mixture of different natural substances named Recapsoma® (bergamot, liposomal berberine, Ipomoea batatas, oleuropein, polycosanols, and vitamin E) has been produced, and its anti-dyslipidaemic efficacy has been tested, specifically studying the in vitro effects on the mechanisms of action underlying cholesterol synthesis, triglycerides, and LDL-cholesterol oxidation. The work has demonstrated the ability of this herbal extract mixture to inhibit the action of PCSK, ACAT, PAP, and HMGR and to increase the LDL receptor (LDLR), underlying the synergistic effect of the mixture over the single components. Such results suggest that the Recapsoma® mixture could be used as a tool for controlling hypercholesterolemia, and an alternative to statins, especially for those patients with metabolic syndrome.
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Affiliation(s)
- Chiara Amante
- Department of Pharmacy, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy; (C.A.); (T.E.); (P.R.)
| | - Tiziana Esposito
- Department of Pharmacy, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy; (C.A.); (T.E.); (P.R.)
| | - Gianni Luccheo
- Laboratori Nutriphyt s.r.l., via Rosario Livatino, 84083 Castel San Giorgio, Italy; (G.L.); (L.L.)
| | - Luigi Luccheo
- Laboratori Nutriphyt s.r.l., via Rosario Livatino, 84083 Castel San Giorgio, Italy; (G.L.); (L.L.)
| | - Paola Russo
- Department of Pharmacy, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy; (C.A.); (T.E.); (P.R.)
| | - Pasquale Del Gaudio
- Department of Pharmacy, University of Salerno, via Giovanni Paolo II, 132, 84084 Fisciano, Italy; (C.A.); (T.E.); (P.R.)
- Correspondence: ; Tel.: +39-089969247; Fax: +39-089969602
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8
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Nutma E, Ceyzériat K, Amor S, Tsartsalis S, Millet P, Owen DR, Papadopoulos V, Tournier BB. Cellular sources of TSPO expression in healthy and diseased brain. Eur J Nucl Med Mol Imaging 2021; 49:146-163. [PMID: 33433698 PMCID: PMC8712293 DOI: 10.1007/s00259-020-05166-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/11/2022]
Abstract
The 18 kDa translocator protein (TSPO) is a highly conserved protein located in the outer mitochondrial membrane. TSPO binding, as measured with positron emission tomography (PET), is considered an in vivo marker of neuroinflammation. Indeed, TSPO expression is altered in neurodegenerative, neuroinflammatory, and neuropsychiatric diseases. In PET studies, the TSPO signal is often viewed as a marker of microglial cell activity. However, there is little evidence in support of a microglia-specific TSPO expression. This review describes the cellular sources and functions of TSPO in animal models of disease and human studies, in health, and in central nervous system diseases. A discussion of methods of analysis and of quantification of TSPO is also presented. Overall, it appears that the alterations of TSPO binding, their cellular underpinnings, and the functional significance of such alterations depend on many factors, notably the pathology or the animal model under study, the disease stage, and the involved brain regions. Thus, further studies are needed to fully determine how changes in TSPO binding occur at the cellular level with the ultimate goal of revealing potential therapeutic pathways.
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Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
| | - Kelly Ceyzériat
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Division of Nuclear medicine and Molecular Imaging, University Hospitals of Geneva, Geneva, Switzerland
- Division of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, Geneva, Switzerland
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - David R Owen
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland.
- Department of Psychiatry, University of Geneva, Geneva, Switzerland.
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9
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Gene Expression Profiling of Skeletal Muscles. Genes (Basel) 2021; 12:genes12111718. [PMID: 34828324 PMCID: PMC8621074 DOI: 10.3390/genes12111718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/21/2021] [Accepted: 10/27/2021] [Indexed: 12/13/2022] Open
Abstract
Next-generation sequencing provides an opportunity for an in-depth biocomputational analysis to identify gene expression patterns between soleus and tibialis anterior, two well-characterized skeletal muscles, and analyze their gene expression profiling. RNA read counts were analyzed for differential gene expression using the R package edgeR. Differentially expressed genes were filtered using a false discovery rate of less than 0.05 c, a fold-change value of more than twenty, and an association with overrepresented pathways based on the Reactome pathway over-representation analysis tool. Most of the differentially expressed genes associated with soleus are coded for components of lipid metabolism and unique contractile elements. Differentially expressed genes associated with tibialis anterior encoded mostly for glucose and glycogen metabolic pathway regulatory enzymes and calcium-sensitive contractile components. These gene expression distinctions partly explain the genetic basis for skeletal muscle specialization, and they may help to explain skeletal muscle susceptibility to disease and drugs and further refine tissue engineering approaches.
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Attwood MM, Schiöth HB. Characterization of Five Transmembrane Proteins: With Focus on the Tweety, Sideroflexin, and YIP1 Domain Families. Front Cell Dev Biol 2021; 9:708754. [PMID: 34350187 PMCID: PMC8327215 DOI: 10.3389/fcell.2021.708754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/28/2021] [Indexed: 11/25/2022] Open
Abstract
Transmembrane proteins are involved in many essential cell processes such as signal transduction, transport, and protein trafficking, and hence many are implicated in different disease pathways. Further, as the structure and function of proteins are correlated, investigating a group of proteins with the same tertiary structure, i.e., the same number of transmembrane regions, may give understanding about their functional roles and potential as therapeutic targets. This analysis investigates the previously unstudied group of proteins with five transmembrane-spanning regions (5TM). More than half of the 58 proteins identified with the 5TM architecture belong to 12 families with two or more members. Interestingly, more than half the proteins in the dataset function in localization activities through movement or tethering of cell components and more than one-third are involved in transport activities, particularly in the mitochondria. Surprisingly, no receptor activity was identified within this dataset in large contrast with other TM groups. The three major 5TM families, which comprise nearly 30% of the dataset, include the tweety family, the sideroflexin family and the Yip1 domain (YIPF) family. We also analyzed the evolutionary origin of these three families. The YIPF family appears to be the most ancient with presence in bacteria and archaea, while the tweety and sideroflexin families are first found in eukaryotes. We found no evidence of common decent for these three families. About 30% of the 5TM proteins have prominent expression in the brain, liver, or testis. Importantly, 60% of these proteins are identified as cancer prognostic markers, where they are associated with clinical outcomes of various tumor types. Nearly 10% of the 5TMs are still not fully characterized and further investigation of their functional activities and expression is warranted. This study provides the first comprehensive analysis of proteins with the 5TM architecture, providing details of their unique characteristics.
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Affiliation(s)
- Misty M Attwood
- Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Helgi B Schiöth
- Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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11
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Oyagawa CRM, Grimsey NL. Cannabinoid receptor CB 1 and CB 2 interacting proteins: Techniques, progress and perspectives. Methods Cell Biol 2021; 166:83-132. [PMID: 34752341 DOI: 10.1016/bs.mcb.2021.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cannabinoid receptors 1 and 2 (CB1 and CB2) are implicated in a range of physiological processes and have gained attention as promising therapeutic targets for a number of diseases. Protein-protein interactions play an integral role in modulating G protein-coupled receptor (GPCR) expression, subcellular distribution and signaling, and the identification and characterization of these will not only improve our understanding of GPCR function and biology, but may provide a novel avenue for therapeutic intervention. A variety of techniques are currently being used to investigate GPCR protein-protein interactions, including Förster/fluorescence and bioluminescence resonance energy transfer (FRET and BRET), proximity ligation assay (PLA), and bimolecular fluorescence complementation (BiFC). However, the reliable application of these methodologies is dependent on the use of appropriate controls and the consideration of the physiological context. Though not as extensively characterized as some other GPCRs, the investigation of CB1 and CB2 interacting proteins is a growing area of interest, and a range of interacting partners have been identified to date. This review summarizes the current state of the literature regarding the cannabinoid receptor interactome, provides commentary on the methodologies and techniques utilized, and discusses future perspectives.
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Affiliation(s)
- Caitlin R M Oyagawa
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Natasha L Grimsey
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.
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12
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Giordani A, Menziani MC, Moresco RM, Matarrese M, Paolino M, Saletti M, Giuliani G, Anzini M, Cappelli A. Exploring Translocator Protein (TSPO) Medicinal Chemistry: An Approach for Targeting Radionuclides and Boron Atoms to Mitochondria. J Med Chem 2021; 64:9649-9676. [PMID: 34254805 DOI: 10.1021/acs.jmedchem.1c00379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Translocator protein 18 kDa [TSPO or peripheral-type benzodiazepine receptor (PBR)] was identified in the search of binding sites for benzodiazepine anxiolytic drugs in peripheral regions. In these areas, binding sites for TSPO ligands were recognized in steroid-producing tissues. TSPO plays an important role in many cellular functions, and its coding sequence is highly conserved across species. TSPO is located predominantly on the membrane of mitochondria and is overexpressed in several solid cancers. TSPO basal expression in the CNS is low, but it becomes high in neurodegenerative conditions. Thus, TSPO constitutes not only as an outstanding drug target but also as a valuable marker for the diagnosis of a number of diseases. The aim of the present article is to show the lesson we have learned from our activity in TSPO medicinal chemistry and in approaching the targeted delivery to mitochondria by means of TSPO ligands.
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Affiliation(s)
- Antonio Giordani
- Rottapharm Biotech S.p.A., Via Valosa di Sopra 9, 20900 Monza, Italy
| | - Maria Cristina Menziani
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41121 Modena, Italy
| | - Rosa Maria Moresco
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Mario Matarrese
- Department of Medicine and Surgery, University of Milan-Bicocca, Nuclear Medicine Department, San Raffaele Scientific Institute, IBFM-CNR, Via Olgettina 60, 20132 Milano, Italy
| | - Marco Paolino
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Mario Saletti
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Germano Giuliani
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Maurizio Anzini
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
| | - Andrea Cappelli
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022), Università di Siena, Via A. Moro 2, 53100 Siena, Italy
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Hiser C, Montgomery BL, Ferguson-Miller S. TSPO protein binding partners in bacteria, animals, and plants. J Bioenerg Biomembr 2021; 53:463-487. [PMID: 34191248 PMCID: PMC8243069 DOI: 10.1007/s10863-021-09905-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/12/2021] [Indexed: 12/11/2022]
Abstract
The ancient membrane protein TSPO is phylogenetically widespread from archaea and bacteria to insects, vertebrates, plants, and fungi. TSPO’s primary amino acid sequence is only modestly conserved between diverse species, although its five transmembrane helical structure appears mainly conserved. Its cellular location and orientation in membranes have been reported to vary between species and tissues, with implications for potential diverse binding partners and function. Most TSPO functions relate to stress-induced changes in metabolism, but in many cases it is unclear how TSPO itself functions—whether as a receptor, a sensor, a transporter, or a translocator. Much evidence suggests that TSPO acts indirectly by association with various protein binding partners or with endogenous or exogenous ligands. In this review, we focus on proteins that have most commonly been invoked as TSPO binding partners. We suggest that TSPO was originally a bacterial receptor/stress sensor associated with porphyrin binding as its most ancestral function and that it later developed additional stress-related roles in eukaryotes as its ability to bind new partners evolved.
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Affiliation(s)
- Carrie Hiser
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
| | - Beronda L Montgomery
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
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14
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Lasunción MA, Martínez-Botas J, Martín-Sánchez C, Busto R, Gómez-Coronado D. Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids. Biochem Pharmacol 2021; 196:114623. [PMID: 34052188 DOI: 10.1016/j.bcp.2021.114623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022]
Abstract
The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.
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Affiliation(s)
- Miguel A Lasunción
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Javier Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Covadonga Martín-Sánchez
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain
| | - Rebeca Busto
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Diego Gómez-Coronado
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
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15
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A new role of glutathione peroxidase 4 during human erythroblast enucleation. Blood Adv 2021; 4:5666-5680. [PMID: 33211827 DOI: 10.1182/bloodadvances.2020003100] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
The selenoprotein glutathione peroxidase 4 (GPX4), the only member of the glutathione peroxidase family able to directly reduce cell membrane-oxidized fatty acids and cholesterol, was recently identified as the central regulator of ferroptosis. GPX4 knockdown in mouse hematopoietic cells leads to hemolytic anemia and to increased spleen erythroid progenitor death. The role of GPX4 during human erythropoiesis is unknown. Using in vitro erythroid differentiation, we show here that GPX4-irreversible inhibition by 1S,3R-RSL3 (RSL3) and its short hairpin RNA-mediated knockdown strongly impaired enucleation in a ferroptosis-independent manner not restored by tocopherol or iron chelators. During enucleation, GPX4 localized with lipid rafts at the cleavage furrows between reticulocytes and pyrenocytes. Its inhibition impacted enucleation after nuclear condensation and polarization and was associated with a defect in lipid raft clustering (cholera toxin staining) and myosin-regulatory light-chain phosphorylation. Because selenoprotein translation and cholesterol synthesis share a common precursor, we investigated whether the enucleation defect could represent a compensatory mechanism favoring GPX4 synthesis at the expense of cholesterol, known to be abundant in lipid rafts. Lipidomics and filipin staining failed to show any quantitative difference in cholesterol content after RSL3 exposure. However, addition of cholesterol increased cholera toxin staining and myosin-regulatory light-chain phosphorylation, and improved enucleation despite GPX4 knockdown. In summary, we identified GPX4 as a new actor of human erythroid enucleation, independent of its function in ferroptosis control. We described its involvement in lipid raft organization required for contractile ring assembly and cytokinesis, leading in fine to nucleus extrusion.
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16
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Fan J, Papadopoulos V. Mitochondrial TSPO Deficiency Triggers Retrograde Signaling in MA-10 Mouse Tumor Leydig Cells. Int J Mol Sci 2020; 22:ijms22010252. [PMID: 33383772 PMCID: PMC7795497 DOI: 10.3390/ijms22010252] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/10/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial translocator protein (TSPO) has been shown to bind cholesterol with high affinity and is involved in mediating its availability for steroidogenesis. We recently reported that targeted Tspo gene deletion in MA-10 mouse tumor Leydig cells resulted in reduced cAMP-stimulated steroid formation and significant reduction in the mitochondrial membrane potential (ΔΨm) compared to control cells. We hypothesized that ΔΨm reduction in the absence of TSPO probably reflects the dysregulation and/or maintenance failure of some basic mitochondrial function(s). To explore the consequences of TSPO depletion via CRISPR-Cas9-mediated deletion (indel) mutation in MA-10 cells, we assessed the transcriptome changes in TSPO-mutant versus wild-type (Wt) cells using RNA-seq. Gene expression profiles were validated using real-time PCR. We report herein that there are significant changes in nuclear gene expression in Tspo mutant versus Wt cells. The identified transcriptome changes were mapped to several signaling pathways including the regulation of membrane potential, calcium signaling, extracellular matrix, and phagocytosis. This is a retrograde signaling pathway from the mitochondria to the nucleus and is probably the result of changes in expression of several transcription factors, including key members of the NF-κB pathway. In conclusion, TSPO regulates nuclear gene expression through intracellular signaling. This is the first evidence of a compensatory response to the loss of TSPO with transcriptome changes at the cellular level.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
- Correspondence: ; Fax: +1-323-442-1681
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17
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Moras M, Hattab C, Gonzalez-Menendez P, Martino S, Larghero J, Le Van Kim C, Kinet S, Taylor N, Lefevre SD, Ostuni MA. Downregulation of Mitochondrial TSPO Inhibits Mitophagy and Reduces Enucleation during Human Terminal Erythropoiesis. Int J Mol Sci 2020; 21:ijms21239066. [PMID: 33260618 PMCID: PMC7730461 DOI: 10.3390/ijms21239066] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/13/2022] Open
Abstract
Translocator protein (TSPO) and voltage dependent anion channels (VDAC) are two proteins forming a macromolecular complex in the outer mitochondrial membrane that is involved in pleiotropic functions. Specifically, these proteins were described to regulate the clearance of damaged mitochondria by selective mitophagy in non-erythroid immortalized cell lines. Although it is well established that erythroblast maturation in mammals depends on organelle clearance, less is known about mechanisms regulating this clearance throughout terminal erythropoiesis. Here, we studied the effect of TSPO1 downregulation and the action of Ro5-4864, a drug ligand known to bind to the TSPO/VDAC complex interface, in ex vivo human terminal erythropoiesis. We found that both treatments delay mitochondrial clearance, a process associated with reduced levels of the PINK1 protein, which is a key protein triggering canonical mitophagy. We also observed that TSPO1 downregulation blocks erythroblast maturation at the orthochromatic stage, decreases the enucleation rate, and increases cell death. Interestingly, TSPO1 downregulation does not modify reactive oxygen species (ROS) production nor intracellular adenosine triphosphate (ATP) levels. Ro5-4864 treatment recapitulates these phenotypes, strongly suggesting an active role of the TSPO/VDAC complex in selective mitophagy throughout human erythropoiesis. The present study links the function of the TSPO/VDAC complex to the PINK1/Parkin-dependent mitophagy induction during terminal erythropoiesis, leading to the proper completion of erythroid maturation.
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Affiliation(s)
- Martina Moras
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
| | - Claude Hattab
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
| | - Pedro Gonzalez-Menendez
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
- Laboratoire d’Excellence GR-Ex, F-75015 Paris, France
| | - Suella Martino
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
| | - Jerome Larghero
- Unité de Thérapie cellulaire, AP-HP, Hôpital Saint-Louis, F-75010 Paris, France;
| | - Caroline Le Van Kim
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
| | - Sandrina Kinet
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
- Laboratoire d’Excellence GR-Ex, F-75015 Paris, France
| | - Naomi Taylor
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
- Laboratoire d’Excellence GR-Ex, F-75015 Paris, France
- Pediatric Oncology Branch, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Sophie D. Lefevre
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
| | - Mariano A. Ostuni
- Inserm, BIGR, UMR_S1134, Université de Paris, F-75015 Paris, France; (M.M.); (C.H.); (S.M.); (C.L.V.K.); (S.D.L.)
- Institut National de Transfusion Sanguine, F-75015 Paris, France
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, F-34293 Montpellier, France; (P.G.-M.); (S.K.); (N.T.)
- Correspondence: ; Tel.: +33‐1‐4449‐3135
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18
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Visualization of translocator protein (18 kDa) (TSPO) in the retina of diabetic retinopathy rats using fluorine-18-DPA-714. Ann Nucl Med 2020; 34:675-681. [DOI: 10.1007/s12149-020-01495-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/22/2020] [Indexed: 12/08/2022]
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19
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Rao R, Diharce J, Dugué B, Ostuni MA, Cadet F, Etchebest C. Versatile Dimerisation Process of Translocator Protein (TSPO) Revealed by an Extensive Sampling Based on a Coarse-Grained Dynamics Study. J Chem Inf Model 2020; 60:3944-3957. [DOI: 10.1021/acs.jcim.0c00246] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rajas Rao
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
- Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, Faculté des Sciences & Technologies Saint-Denis, F-97715 St. Denis, France
| | - Julien Diharce
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
- Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, Faculté des Sciences & Technologies Saint-Denis, F-97715 St. Denis, France
| | - Bérénice Dugué
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
- Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, Faculté des Sciences & Technologies Saint-Denis, F-97715 St. Denis, France
| | - Mariano A. Ostuni
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
| | - Frédéric Cadet
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
- Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, Faculté des Sciences & Technologies Saint-Denis, F-97715 St. Denis, France
- PEACCEL, Artificial Intelligence Department, 6 Square Albin Cachot, Box 42, 75013 Paris, France
| | - Catherine Etchebest
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, F-75015, Paris, France
- Laboratoire d’Excellence GR-Ex, 75015 Paris, France
- Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, Faculté des Sciences & Technologies Saint-Denis, F-97715 St. Denis, France
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20
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Lee Y, Park Y, Nam H, Lee JW, Yu SW. Translocator protein (TSPO): the new story of the old protein in neuroinflammation. BMB Rep 2020. [PMID: 31818362 PMCID: PMC6999824 DOI: 10.5483/bmbrep.2020.53.1.273] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Translocator protein (TSPO), also known as peripheral benzodiazepine receptor, is a transmembrane protein located on the outer mitochondria membrane (OMM) and mainly expressed in glial cells in the brain. Because of the close correlation of its expression level with neuropathology and therapeutic efficacies of several TSPO binding ligands under many neurological conditions, TSPO has been regarded as both biomarker and therapeutic target, and the biological functions of TSPO have been a major research focus. However, recent genetic studies with animal and cellular models revealed unexpected results contrary to the anticipated biological importance of TSPO and cast doubt on the action modes of the TSPO-binding drugs. In this review, we summarize recent controversial findings on the discrepancy between pharmacological and genetic studies of TSPO and suggest some future direction to understand this old and mysterious protein.
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Affiliation(s)
- Younghwan Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Youngjin Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Hyeri Nam
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Ji-Won Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
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21
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Kiatpakdee B, Sato K, Otsuka Y, Arashiki N, Chen Y, Tsumita T, Otsu W, Yamamoto A, Kawata R, Yamazaki J, Sugimoto Y, Takada K, Mohandas N, Inaba M. Cholesterol-binding protein TSPO2 coordinates maturation and proliferation of terminally differentiating erythroblasts. J Biol Chem 2020; 295:8048-8063. [PMID: 32358067 PMCID: PMC7278357 DOI: 10.1074/jbc.ra119.011679] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 04/20/2020] [Indexed: 02/02/2023] Open
Abstract
TSPO2 (translocator protein 2) is a transmembrane protein specifically expressed in late erythroblasts and has been postulated to mediate intracellular redistribution of cholesterol. We identified TSPO2 as the causative gene for the HK (high-K+) trait with immature red cell phenotypes in dogs and investigated the effects of the TSPO2 defects on erythropoiesis in HK dogs with the TSPO2 mutation and Tspo2 knockout (Tspo2−/−) mouse models. Bone marrow–derived erythroblasts from HK dogs showed increased binucleated and apoptotic cells at various stages of maturation and shed large nuclei with incomplete condensation when cultured in the presence of erythropoietin, indicating impaired maturation and cytokinesis. The canine TSPO2 induces cholesterol accumulation in the endoplasmic reticulum and could thereby regulate cholesterol availability by changing intracellular cholesterol distribution in erythroblasts. Tspo2−/− mice consistently showed impaired cytokinesis with increased binucleated erythroblasts, resulting in compensated anemia, and their red cell membranes had increased Na,K-ATPase, resembling the HK phenotype in dogs. Tspo2-deficient mouse embryonic stem cell–derived erythroid progenitor (MEDEP) cells exhibited similar morphological defects associated with a cell-cycle arrest at the G2/M phase, resulting in decreased cell proliferation and had a depletion in intracellular unesterified and esterified cholesterol. When the terminal maturation was induced, Tspo2−/− MEDEP cells showed delays in hemoglobinization; maturation-associated phenotypic changes in CD44, CD71, and TER119 expression; and cell-cycle progression. Taken together, these findings imply that TSPO2 is essential for coordination of maturation and proliferation of erythroblasts during normal erythropoiesis.
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Affiliation(s)
- Benjaporn Kiatpakdee
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Kota Sato
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yayoi Otsuka
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Nobuto Arashiki
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yuqi Chen
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Takuya Tsumita
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Wataru Otsu
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Akito Yamamoto
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Reo Kawata
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Jumpei Yamazaki
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | | | - Kensuke Takada
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Narla Mohandas
- Red Cell Physiology Laboratory, New York Blood Center, New York, New York, USA
| | - Mutsumi Inaba
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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22
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Manceau H, Lefevre SD, Mirmiran A, Hattab C, Sugier HR, Schmitt C, Peoc'h K, Puy H, Ostuni MA, Gouya L, Lacapere JJ. TSPO2 translocates 5-aminolevulinic acid into human erythroleukemia cells. Biol Cell 2020; 112:113-126. [PMID: 31989647 DOI: 10.1111/boc.201900098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND 5-Aminolevulinic acid (ALA) is the first precursor of heme biosynthesis pathway. The exogenous addition of ALA to cells leads to protoporphyrin IX (PPIX) accumulation that has been exploited in photodynamic diagnostic and photodynamic therapy. Several types of ALA transporters have been described depending on the cell type, but there was no clear entry pathway for erythroid cells. The 18 kDa translocator protein (TSPO) has been proposed to be involved in the transport of porphyrins and heme analogs. RESULTS ALA-induced PPIX accumulation in erythroleukemia cells (UT-7 and K562) was impaired by PK 11195, a competitive inhibitor of both transmembrane proteins TSPO (1 and 2). PK 11195 did not modify the activity of the enzymes of heme biosynthesis, suggesting that ALA entry at the plasma membrane was the limiting factor. In contrast, porphobilinogen (PBG)-induced PPIX accumulation was not affected by PK 11195, suggesting that plasma membrane TSPO2 is a selective transporter of ALA. Overexpression of TSPO2 at the plasma membrane of erythroleukemia cells increased ALA-induced PPIX accumulation, confirming the role of TSPO2 in the import of ALA into the cells. CONCLUSIONS ALA-induced PPIX accumulation in erythroid cells involves TSPO2 as a selective translocator through the plasma membrane. SIGNIFICANCE This is the first characterisation of molecular mechanisms involving a new actor in ALA transport in ALA-induced PPIX accumulation in erythroleukemia cells, which could be inhibited by specific drug ligands.
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Affiliation(s)
- Hana Manceau
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
- Laboratoire de Biochimie, Hôpital Beaujon, Assistance Publique-Hôpitaux de Paris, DHU Unity, 92110, Clichy, France
| | - Sophie D Lefevre
- UMR_S1134, Integrated Biology of Red Blood Cell, INSERM, Université de Paris, F-75015, Paris, France
- Institut National de Transfusion Sanguine, F-75015, Paris, France
| | - Arienne Mirmiran
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
| | - Claude Hattab
- UMR_S1134, Integrated Biology of Red Blood Cell, INSERM, Université de Paris, F-75015, Paris, France
- Institut National de Transfusion Sanguine, F-75015, Paris, France
| | - Hugo R Sugier
- Institut National de Transfusion Sanguine, F-75015, Paris, France
- Université de Paris, UMR_S1134, Integrated Biology of Red Blood Cell, INSERM, F-75015, Paris, France
| | - Caroline Schmitt
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, 92701, Colombes, France
| | - Katell Peoc'h
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
- Laboratoire de Biochimie, Hôpital Beaujon, Assistance Publique-Hôpitaux de Paris, DHU Unity, 92110, Clichy, France
| | - Hervé Puy
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, 92701, Colombes, France
| | - Mariano A Ostuni
- UMR_S1134, Integrated Biology of Red Blood Cell, INSERM, Université de Paris, F-75015, Paris, France
- Institut National de Transfusion Sanguine, F-75015, Paris, France
| | - Laurent Gouya
- Centre de recherche sur l'inflammation, INSERM U1149, Université de Paris, F-75018, Paris, France
- Centre Français des Porphyries, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, 92701, Colombes, France
| | - Jean-Jacques Lacapere
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), F-75005, Paris, France
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23
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Singh A, Dashnyam M, Chim B, Escobar TM, Dulcey AE, Hu X, Wilson KM, Koganti PP, Spinner CA, Xu X, Jadhav A, Southall N, Marugan J, Selvaraj V, Lazarevic V, Muljo SA, Ferrer M. Anxiolytic Drug FGIN-1-27 Ameliorates Autoimmunity by Metabolic Reprogramming of Pathogenic Th17 Cells. Sci Rep 2020; 10:3766. [PMID: 32111885 PMCID: PMC7048748 DOI: 10.1038/s41598-020-60610-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 02/11/2020] [Indexed: 01/10/2023] Open
Abstract
Th17 cells are critical drivers of autoimmune diseases and immunopathology. There is an unmet need to develop therapies targeting pathogenic Th17 cells for the treatment of autoimmune disorders. Here, we report that anxiolytic FGIN-1-27 inhibits differentiation and pathogenicity of Th17 cells in vitro and in vivo using the experimental autoimmune encephalomyelitis (EAE) model of Th17 cell-driven pathology. Remarkably, we found that the effects of FGIN-1-27 were independent of translocator protein (TSPO), the reported target for this small molecule, and instead were driven by a metabolic switch in Th17 cells that led to the induction of the amino acid starvation response and altered cellular fatty acid composition. Our findings suggest that the small molecule FGIN-1-27 can be re-purposed to relieve autoimmunity by metabolic reprogramming of pathogenic Th17 cells.
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Affiliation(s)
- Anju Singh
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Myagmarjav Dashnyam
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Bryan Chim
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Thelma M Escobar
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Andrés E Dulcey
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Xin Hu
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Kelli M Wilson
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Prasanthi P Koganti
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Camille A Spinner
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Xin Xu
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Ajit Jadhav
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Noel Southall
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Juan Marugan
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA
| | - Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Vanja Lazarevic
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Stefan A Muljo
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA.
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, Rockville, MD, USA.
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24
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Fan J, Campioli E, Sottas C, Zirkin B, Papadopoulos V. Amhr2-Cre-Mediated Global Tspo Knockout. J Endocr Soc 2020; 4:bvaa001. [PMID: 32099945 PMCID: PMC7031085 DOI: 10.1210/jendso/bvaa001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/27/2022] Open
Abstract
Although the role of translocator protein (TSPO) in cholesterol transport in steroid-synthesizing cells has been studied extensively, recent studies of TSPO genetic depletion have questioned its role. Amhr2-Cre mice have been used to generate Leydig cell-specific Tspo conditional knockout (cKO) mice. Using the same Cre line, we were unable to generate Tspo cKO mice possibly because of genetic linkage between Tspo and Amhr2 and coexpression of Amhr2-Cre and Tspo in early embryonic development. We found that Amhr2-Cre is expressed during preimplantation stages, resulting in global heterozygous mice (gHE; Amhr2-Cre+/–,Tspo–/+). Two gHE mice were crossed, generating Amhr2-Cre–mediated Tspo global knockout (gKO; Tspo–/–) mice. We found that 33.3% of blastocysts at E3.5 to E4.5 showed normal morphology, whereas 66.7% showed delayed development, which correlates with the expected Mendelian proportions of Tspo+/+ (25%), Tspo–/– (25%), and Tspo+/– (50%) genotypes from crossing 2 Tspo–/+ mice. Adult Tspo gKO mice exhibited disturbances in neutral lipid homeostasis and reduced intratesticular and circulating testosterone levels, but no change in circulating basal corticosterone levels. RNA-sequencing data from mouse adrenal glands and lungs revealed transcriptome changes in response to the loss of TSPO, including changes in several cholesterol-binding and transfer proteins. This study demonstrates that Amhr2-Cre can be used to produce Tspo gKO mice instead of cKO, and can serve as a new global “Cre deleter.” Moreover, our results show that Tspo deletion causes delayed preimplantation embryonic development, alters neutral lipid storage and steroidogenesis, and leads to transcriptome changes that may reflect compensatory mechanisms in response to the loss of function of TSPO.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Chantal Sottas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, US
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
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25
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Effects of age, BMI and sex on the glial cell marker TSPO - a multicentre [ 11C]PBR28 HRRT PET study. Eur J Nucl Med Mol Imaging 2019; 46:2329-2338. [PMID: 31363804 PMCID: PMC6717599 DOI: 10.1007/s00259-019-04403-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/14/2019] [Indexed: 01/25/2023]
Abstract
Purpose The purpose of this study was to investigate the effects of ageing, sex and body mass index (BMI) on translocator protein (TSPO) availability in healthy subjects using positron emission tomography (PET) and the radioligand [11C]PBR28. Methods [11C]PBR28 data from 140 healthy volunteers (72 males and 68 females; N = 78 with HAB and N = 62 MAB genotype; age range 19–80 years; BMI range 17.6–36.9) were acquired with High Resolution Research Tomograph at three centres: Karolinska Institutet (N = 53), Turku PET centre (N = 62) and Yale University PET Center (N = 25). The total volume of distribution (VT) was estimated in global grey matter, frontal, temporal, occipital and parietal cortices, hippocampus and thalamus using multilinear analysis 1. The effects of age, BMI and sex on TSPO availability were investigated using linear mixed effects model, with TSPO genotype and PET centre specified as random intercepts. Results There were significant positive correlations between age and VT in the frontal and temporal cortex. BMI showed a significant negative correlation with VT in all regions. Additionally, significant differences between males and females were observed in all regions, with females showing higher VT. A subgroup analysis revealed a positive correlation between VT and age in all regions in male subjects, whereas age showed no effect on TSPO levels in female subjects. Conclusion These findings provide evidence that individual biological properties may contribute significantly to the high variation shown in TSPO binding estimates, and suggest that age, BMI and sex can be confounding factors in clinical studies. Electronic supplementary material The online version of this article (10.1007/s00259-019-04403-7) contains supplementary material, which is available to authorized users.
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26
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Iatmanen-Harbi S, Senicourt L, Papadopoulos V, Lequin O, Lacapere JJ. Characterization of the High-Affinity Drug Ligand Binding Site of Mouse Recombinant TSPO. Int J Mol Sci 2019; 20:ijms20061444. [PMID: 30901938 PMCID: PMC6470738 DOI: 10.3390/ijms20061444] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 02/08/2023] Open
Abstract
The optimization of translocator protein (TSPO) ligands for Positron Emission Tomography as well as for the modulation of neurosteroids is a critical necessity for the development of TSPO-based diagnostics and therapeutics of neuropsychiatrics and neurodegenerative disorders. Structural hints on the interaction site and ligand binding mechanism are essential for the development of efficient TSPO ligands. Recently published atomic structures of recombinant mammalian and bacterial TSPO1, bound with either the high-affinity drug ligand PK 11195 or protoporphyrin IX, have revealed the membrane protein topology and the ligand binding pocket. The ligand is surrounded by amino acids from the five transmembrane helices as well as the cytosolic loops. However, the precise mechanism of ligand binding remains unknown. Previous biochemical studies had suggested that ligand selectivity and binding was governed by these loops. We performed site-directed mutagenesis to further test this hypothesis and measured the binding affinities. We show that aromatic residues (Y34 and F100) from the cytosolic loops contribute to PK 11195 access to its binding site. Limited proteolytic digestion, circular dichroism and solution two-dimensional (2-D) NMR using selective amino acid labelling provide information on the intramolecular flexibility and conformational changes in the TSPO structure upon PK 11195 binding. We also discuss the differences in the PK 11195 binding affinities and the primary structure between TSPO (TSPO1) and its paralogous gene product TSPO2.
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Affiliation(s)
- Soria Iatmanen-Harbi
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Lucile Senicourt
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA.
| | - Olivier Lequin
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Jean-Jacques Lacapere
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
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27
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Simvastatin-induced Changes in the Leukocytic System of Porcine Bone Marrow. J Vet Res 2018; 62:329-333. [PMID: 30584612 PMCID: PMC6296003 DOI: 10.2478/jvetres-2018-0034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/28/2018] [Indexed: 12/03/2022] Open
Abstract
Introduction Simvastatin is a substance which is commonly used as a medicine to reduce cholesterol level. Unfortunately, it shows numerous side effects. Simvastatin affects various internal organs, and among other detriments to health may cause persistent muscle weakness, osteolytic processes, headaches, and rashes. Until now knowledge of the influence of simvastatin on bone marrow cells has been rather scant and fragmentary. Material and Methods During this experiment the numbers of all types of cells in the leukocytic system of porcine bone marrow were evaluated after 28 and 56 days of oral administration of simvastatin at a dose of 40 mg/day/animal. Results Simvastatin caused an increase in the number of all types of cells in the leukocytic system, and the most visible fluctuations concerned promyelocytes. Conclusion Observations obtained during the present study indicated that the results of the action of simvastatin on porcine bone marrow differ from those observed in other mammal species, including human. This may be due to various metabolic pathways within the bone marrow in the particular species, but the exact mechanisms of these actions are unknown at the present time.
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28
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Marginedas-Freixa I, Alvarez CL, Moras M, Hattab C, Bouyer G, Chene A, Lefevre SD, Le Van Kim C, Bihel F, Schwarzbaum PJ, Ostuni MA. Induction of ATP Release, PPIX Transport, and Cholesterol Uptake by Human Red Blood Cells Using a New Family of TSPO Ligands. Int J Mol Sci 2018; 19:ijms19103098. [PMID: 30308949 PMCID: PMC6213633 DOI: 10.3390/ijms19103098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/05/2018] [Accepted: 10/07/2018] [Indexed: 02/07/2023] Open
Abstract
Two main isoforms of the Translocator Protein (TSPO) have been identified. TSPO1 is ubiquitous and is mainly present at the outer mitochondrial membrane of most eukaryotic cells, whereas, TSPO2 is specific to the erythroid lineage, located at the plasma membrane, the nucleus, and the endoplasmic reticulum. The design of specific tools is necessary to determine the molecular associations and functions of TSPO, which remain controversial nowadays. We recently demonstrated that TSPO2 is involved in a supramolecular complex of the erythrocyte membrane, where micromolar doses of the classical TSPO ligands induce ATP release and zinc protoporphyrin (ZnPPIX) transport. In this work, three newly-designed ligands (NCS1016, NCS1018, and NCS1026) were assessed for their ability to modulate the functions of various erythrocyte's and compare them to the TSPO classical ligands. The three new ligands were effective in reducing intraerythrocytic Plasmodium growth, without compromising erythrocyte survival. While NCS1016 and NCS1018 were the most effective ligands in delaying sorbitol-induced hemolysis, NCS1016 induced the highest uptake of ZnPPIX and NCS1026 was the only ligand inhibiting the cholesterol uptake. Differential effects of ligands are probably due, not only, to ligand features, but also to the dynamic interaction of TSPO with various partners at the cell membrane. Further studies are necessary to fully understand the mechanisms of the TSPO's complex activation.
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Affiliation(s)
- Irene Marginedas-Freixa
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Cora L Alvarez
- Instituto de Química y Fisico-Química Biológicas "Prof. Alejandro C. Paladini", UBA, CONICET, Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina.
- Departamento de Biodiversidad y Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina.
| | - Martina Moras
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Claude Hattab
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Guillaume Bouyer
- UMR 8227 LBI2M, Comparative Erythrocyte's Physiology, CNRS, Sorbonne Université, Laboratoire d'Excellence GR-Ex, F-29680 Roscoff, France.
| | - Arnaud Chene
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Sophie D Lefevre
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Caroline Le Van Kim
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
| | - Frederic Bihel
- UMR7200, Laboratoire d'Innovation Thérapeutique, Faculty of Pharmacy, University of Strasbourg, CNRS, F-67400 Illkirch Graffenstaden, France.
| | - Pablo J Schwarzbaum
- Instituto de Química y Fisico-Química Biológicas "Prof. Alejandro C. Paladini", UBA, CONICET, Facultad de Farmacia y Bioquímica, Junín 956, C1113AAD Buenos Aires, Argentina.
- Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina.
| | - Mariano A Ostuni
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015 Paris, France.
- Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015 Paris, France.
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29
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Marginedas-Freixa I, Alvarez CL, Moras M, Leal Denis MF, Hattab C, Halle F, Bihel F, Mouro-Chanteloup I, Lefevre SD, Le Van Kim C, Schwarzbaum PJ, Ostuni MA. Human erythrocytes release ATP by a novel pathway involving VDAC oligomerization independent of pannexin-1. Sci Rep 2018; 8:11384. [PMID: 30061676 PMCID: PMC6065367 DOI: 10.1038/s41598-018-29885-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 07/20/2018] [Indexed: 12/14/2022] Open
Abstract
We previously demonstrated that the translocase protein TSPO2 together with the voltage-dependent anion channel (VDAC) and adenine nucleotide transporter (ANT) were involved in a membrane transport complex in human red blood cells (RBCs). Because VDAC was proposed as a channel mediating ATP release in RBCs, we used TSPO ligands together with VDAC and ANT inhibitors to test this hypothesis. ATP release was activated by TSPO ligands, and blocked by inhibitors of VDAC and ANT, while it was insensitive to pannexin-1 blockers. TSPO ligand increased extracellular ATP (ATPe) concentration by 24–59% over the basal values, displaying an acute increase in [ATPe] to a maximal value, which remained constant thereafter. ATPe kinetics were compatible with VDAC mediating a fast but transient ATP efflux. ATP release was strongly inhibited by PKC and PKA inhibitors as well as by depleting intracellular cAMP or extracellular Ca2+, suggesting a mechanism involving protein kinases. TSPO ligands favoured VDAC polymerization yielding significantly higher densities of oligomeric bands than in unstimulated cells. Polymerization was partially inhibited by decreasing Ca2+ and cAMP contents. The present results show that TSPO ligands induce polymerization of VDAC, coupled to activation of ATP release by a supramolecular complex involving VDAC, TSPO2 and ANT.
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Affiliation(s)
- Irene Marginedas-Freixa
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - Cora Lilia Alvarez
- Instituto de Química y Fisico-Química Biológicas "Prof. Alejandro C. Paladini", UBA, CONICET, Facultad de Farmacia y Bioquímica, Junín 956, Buenos Aires, Argentina.,Universidad de Buenos Aires. Facultad Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
| | - Martina Moras
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - María Florencia Leal Denis
- Instituto de Química y Fisico-Química Biológicas "Prof. Alejandro C. Paladini", UBA, CONICET, Facultad de Farmacia y Bioquímica, Junín 956, Buenos Aires, Argentina.,Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Analítica y Fisicoquímica, Cátedra de Química Analítica, Buenos Aires, Argentina
| | - Claude Hattab
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - François Halle
- UMR7200, Laboratoire d'Innovation Thérapeutique, Faculty of Pharmacy, University of Strasbourg, CNRS, 67400, Illkirch Graffenstaden, France
| | - Frédéric Bihel
- UMR7200, Laboratoire d'Innovation Thérapeutique, Faculty of Pharmacy, University of Strasbourg, CNRS, 67400, Illkirch Graffenstaden, France
| | - Isabelle Mouro-Chanteloup
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - Sophie Denise Lefevre
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - Caroline Le Van Kim
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - Pablo Julio Schwarzbaum
- Instituto de Química y Fisico-Química Biológicas "Prof. Alejandro C. Paladini", UBA, CONICET, Facultad de Farmacia y Bioquímica, Junín 956, Buenos Aires, Argentina.,Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica. Cátedra de Química Biológica Superior, Buenos Aires, Argentina
| | - Mariano Anibal Ostuni
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Université de la Réunion, Université des Antilles, F-75015, Paris, France. .,Institut National de la Transfusion Sanguine, Laboratoire d'Excellence GR-Ex, F-75015, Paris, France.
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30
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Lima-Maximino MG, Cueto-Escobedo J, Rodríguez-Landa JF, Maximino C. FGIN-1-27, an agonist at translocator protein 18 kDa (TSPO), produces anti-anxiety and anti-panic effects in non-mammalian models. Pharmacol Biochem Behav 2018; 171:66-73. [PMID: 29698632 DOI: 10.1016/j.pbb.2018.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 11/19/2022]
Abstract
FGIN-1-27 is an agonist at the translocator protein 18 kDa (TSPO), a cholesterol transporter that is associated with neurosteroidogenesis. This protein has been identified as a peripheral binding site for benzodiazepines; in anamniotes, however, a second TSPO isoform that is absent in amniotes has been implicated in erythropoiesis. Functional conservation of the central benzodiazepine-binding site located in the GABAA receptors has been demonstrated in anamniotes and amniotes alike; however, it was not previously demonstrated for TSPO. The present investigation explored the behavioral effects of FGIN-1-27 on an anxiety test in zebrafish (Danio rerio, Family: Cyprinide) and on a mixed anxiety/panic test on wall lizards (Tropidurus oreadicus, Family: Tropiduridae). Results showed that FGIN-1-27 reduced anxiety-like behavior in the zebrafish light/dark preference test similar to diazepam, but with fewer sedative effects. Similarly, FGIN-1-27 also reduced anxiety- and fear-like behaviors in the defense test battery in wall lizards, again producing fewer sedative-like effects than diazepam; the benzodiazepine was also unable to reduce fear-like behaviors in this species. These results A) underline the functional conservation of TSPO in defensive behavior in anamniotes; B) strengthen the proposal of using anamniote behavior as models in behavioral pharmacology; and C) suggest TSPO/neurosteroidogenesis as a target in treating anxiety disorders.
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Affiliation(s)
- Monica Gomes Lima-Maximino
- Laboratório de Neurofarmacologia e Biofísica, Departamento de Morfologia e Ciências Fisiológicas, Universidade do Estado do Pará - Campus VIII, Marabá, Brazil
| | - Jonathan Cueto-Escobedo
- Laboratorio de Neurofarmacología, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Mexico
| | | | - Caio Maximino
- Instituto de Estudos em Saúde e Biológicas, Universidade Federal do Sul e Sudeste do Pará, Marabá, Brazil.
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Fan J, Wang K, Zirkin B, Papadopoulos V. CRISPR/Cas9‒Mediated Tspo Gene Mutations Lead to Reduced Mitochondrial Membrane Potential and Steroid Formation in MA-10 Mouse Tumor Leydig Cells. Endocrinology 2018; 159:1130-1146. [PMID: 29300865 PMCID: PMC5793793 DOI: 10.1210/en.2017-03065] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 12/21/2017] [Indexed: 12/17/2022]
Abstract
The outer mitochondrial membrane translocator protein (TSPO) binds cholesterol with high affinity and is involved in mediating its delivery into mitochondria, the rate-limiting step in hormone-induced steroidogenesis. Specific ligand binding to TSPO has been shown to initiate steroid formation. However, recent studies of the genetic deletion of Tspo have provided conflicting results. Here, we address and extend previous studies by examining the effects of Tspo-specific mutations on steroid formation in hormone- and cyclic adenosine monophosphate (cAMP)-responsive MA-10 cells, using the CRISPR/Cas9 system. Two mutant subcell lines, nG1 and G2G, each carrying a Tspo exon2-specific genome modification, and two control subcell lines, G1 and HH, each carrying a wild-type Tspo, were produced. In response to dibutyryl cAMP, the nG1 and G2G cells produced progesterone at levels significantly lower than those produced by the corresponding control cells G1 and HH. Neutral lipid homeostasis, which provides free cholesterol for steroid biosynthesis, was altered significantly in the Tspo mutant cells. Interestingly, the mitochondrial membrane potential (ΔΨm) of the Tspo mutant cells was significantly reduced compared with that of the control cells, likely because of TSPO interactions with the voltage-dependent anion channel and tubulin at the outer mitochondrial membrane. Steroidogenic acute regulatory protein (STAR) expression was induced in nG1 cells, suggesting that reduced TSPO affected STAR synthesis and/or processing. Taken together, these results provide further evidence for the critical role of TSPO in steroid biosynthesis and suggest that it may function at least in part via its regulation of ΔΨm and effects on STAR.
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Affiliation(s)
- Jinjiang Fan
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Kevin Wang
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre and Department of Medicine, Faculty of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089
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Zhang YH, Hu Y, Zhang Y, Hu LD, Kong X. Distinguishing three subtypes of hematopoietic cells based on gene expression profiles using a support vector machine. Biochim Biophys Acta Mol Basis Dis 2017; 1864:2255-2265. [PMID: 29241664 DOI: 10.1016/j.bbadis.2017.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/20/2017] [Accepted: 12/01/2017] [Indexed: 02/08/2023]
Abstract
Hematopoiesis is a complicated process involving a series of biological sub-processes that lead to the formation of various blood components. A widely accepted model of early hematopoiesis proceeds from long-term hematopoietic stem cells (LT-HSCs) to multipotent progenitors (MPPs) and then to lineage-committed progenitors. However, the molecular mechanisms of early hematopoiesis have not been fully characterized. In this study, we applied a computational strategy to identify the gene expression signatures distinguishing three types of closely related hematopoietic cells collected in recent studies: (1) hematopoietic stem cell/multipotent progenitor cells; (2) LT-HSCs; and (3) hematopoietic progenitor cells. Each cell in these cell types was represented by its gene expression profile among a total number of 20,475 genes. The expression features were analyzed by a Monte-Carlo Feature Selection (MCFS) method, resulting in a feature list. Then, the incremental feature selection (IFS) and a support vector machine (SVM) optimized with a sequential minimum optimization (SMO) algorithm were employed to access the optimal classifier with the highest Matthews correlation coefficient (MCC) value of 0.889, in which 6698 features were used to represent cells. In addition, through an updated program of MCFS method, seventeen decision rules can be obtained, which can classify the three cell types with an overall accuracy of 0.812. Using a literature review, both the rules and the top features used for building the optimal classifier were confirmed to be commonly used or potential biological markers for distinguishing the three cell types of HSPCs. This article is part of a Special Issue entitled: Accelerating Precision Medicine through Genetic and Genomic Big Data Analysis edited by Yudong Cai & Tao Huang.
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Affiliation(s)
- Yu-Hang Zhang
- Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
| | - Yu Hu
- Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
| | - Yuchao Zhang
- Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.
| | - Lan-Dian Hu
- Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.
| | - Xiangyin Kong
- Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.
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Jaipuria G, Leonov A, Giller K, Vasa SK, Jaremko Ł, Jaremko M, Linser R, Becker S, Zweckstetter M. Cholesterol-mediated allosteric regulation of the mitochondrial translocator protein structure. Nat Commun 2017; 8:14893. [PMID: 28358007 PMCID: PMC5379104 DOI: 10.1038/ncomms14893] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/08/2017] [Indexed: 12/02/2022] Open
Abstract
Cholesterol is an important regulator of membrane protein function. However, the exact mechanisms involved in this process are still not fully understood. Here we study how the tertiary and quaternary structure of the mitochondrial translocator protein TSPO, which binds cholesterol with nanomolar affinity, is affected by this sterol. Residue-specific analysis of TSPO by solid-state NMR spectroscopy reveals a dynamic monomer–dimer equilibrium of TSPO in the membrane. Binding of cholesterol to TSPO's cholesterol-recognition motif leads to structural changes across the protein that shifts the dynamic equilibrium towards the translocator monomer. Consistent with an allosteric mechanism, a mutation within the oligomerization interface perturbs transmembrane regions located up to 35 Å away from the interface, reaching TSPO's cholesterol-binding motif. The lower structural stability of the intervening transmembrane regions provides a mechanistic basis for signal transmission. Our study thus reveals an allosteric signal pathway that connects membrane protein tertiary and quaternary structure with cholesterol binding. The outer mitochondrial membrane translocator protein (TSPO) mediates several mitochondrial functions and binds cholesterol with a high affinity. Here the authors use solid-state NMR to show that cholesterol binding to TSPO results in allosteric changes that modulate TSPO oligomerization.
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Affiliation(s)
- Garima Jaipuria
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Strasse 3a, 37075 Göttingen, Germany
| | - Andrei Leonov
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Karin Giller
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Suresh Kumar Vasa
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Łukasz Jaremko
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Strasse 3a, 37075 Göttingen, Germany
| | - Mariusz Jaremko
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Rasmus Linser
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Stefan Becker
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
| | - Markus Zweckstetter
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Strasse 3a, 37075 Göttingen, Germany.,Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany.,Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073 Göttingen, Germany
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Liu X, Liu H, Xu S, Tang Z, Xia W, Cheng Z, Li W, Jin Y. Spinal translocator protein alleviates chronic neuropathic pain behavior and modulates spinal astrocyte-neuronal function in rats with L5 spinal nerve ligation model. Pain 2016; 157:103-116. [PMID: 26307860 DOI: 10.1097/j.pain.0000000000000339] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Recent studies reported the translocator protein (TSPO) to play critical roles in several kinds of neurological diseases including the inflammatory and neuropathic pain. However, the precise mechanism remains unclear. This study was undertaken to explore the distribution and possible mechanism of spinal TSPO against chronic neuropathic pain (CNP) in a rat model of L5 spinal nerve ligation (SNL). Our results showed that TSPO was upregulated in a time-related manner in the spinal dorsal horn after SNL. Spinal TSPO was predominately expressed in astrocytes. A single intrathecal injection of TSPO agonist Ro5-4864, but not TSPO antagonist PK11195, alleviated the mechanical allodynia in a dose-dependent manner. A single intraspinal injection of TSPO overexpression lentivirus (LV-TSPO), but not TSPO inhibited lentivirus (LV-shTSPO), also relieved the development of CNP. Intrathecal administration of 2 μg Ro5-4864 on day 3 induced a significant increase of TSPO protein content at the early stage (days 5-7) while inhibited the TSPO activation during the chronic period (days 14-21) compared with the control group. Ro5-4864 suppressed the astrocytes and p-JNK1 activation and decreased the CXCL1 expression in both in vivo and in vitro studies. Ro5-4864 also attenuated the spinal CXCR2 and p-ERK expressions. These results suggested that early upregulation of TSPO could elicit potent analgesic effects against CNP, which might be partly attributed to the inhibition of CXCL1-CXCR2-dependent astrocyte-to-neuron signaling and central sensitization. TSPO signaling pathway may present a novel strategy for the treatment of CNP.
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Affiliation(s)
- Xiaoming Liu
- Pain Management Center, Department of Anesthesiology, Nanjing Jinling Hospital, Nanjing, China Laboratory of Medical Neurobiology, School of Basic Medical Science, Nanjing University of Traditional Chinese Medicine, Nanjing, China School of Bio-medical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China
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Selvaraj V, Tu LN. Current status and future perspectives: TSPO in steroid neuroendocrinology. J Endocrinol 2016; 231:R1-R30. [PMID: 27422254 DOI: 10.1530/joe-16-0241] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/15/2016] [Indexed: 12/21/2022]
Abstract
The mitochondrial translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), has received significant attention both as a diagnostic biomarker and as a therapeutic target for different neuronal disease pathologies. Recently, its functional basis believed to be mediating mitochondrial cholesterol import for steroid hormone production has been refuted by studies examining both in vivo and in vitro genetic Tspo-deficient models. As a result, there now exists a fundamental gap in the understanding of TSPO function in the nervous system, and its putative pharmacology in neurosteroid production. In this review, we discuss several recent findings in steroidogenic cells that are in direct contradiction to previous studies, and necessitate a re-examination of the purported role for TSPO in de novo neurosteroid biosynthesis. We critically examine the pharmacological effects of different TSPO-binding drugs with particular focus on studies that measure neurosteroid levels. We highlight the basis of key misconceptions regarding TSPO that continue to pervade the literature, and the need for interpretation with caution to avoid negative impacts. We also summarize the emerging perspectives that point to new directions that need to be investigated for understanding the molecular function of TSPO, only after which the true potential of this therapeutic target in medicine may be realized.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal ScienceCornell University, Ithaca, New York, USA
| | - Lan N Tu
- Department of Animal ScienceCornell University, Ithaca, New York, USA
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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.
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Fanizza E, Iacobazzi RM, Laquintana V, Valente G, Caliandro G, Striccoli M, Agostiano A, Cutrignelli A, Lopedota A, Curri ML, Franco M, Depalo N, Denora N. Highly selective luminescent nanostructures for mitochondrial imaging and targeting. NANOSCALE 2016; 8:3350-3361. [PMID: 26763470 DOI: 10.1039/c5nr08139d] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Here a luminescent hybrid nanostructure based on functionalized quantum dots (QDs) is used as a fluorescent imaging agent able to target selectively mitochondria thanks to the molecular recognition of the translocator protein (TSPO). The selective targeting of such an 18 kDa protein mainly located in the outer mitochondrial membrane and overexpressed in several pathological states including neurodegenerative diseases and cancers may provide valuable information for the early diagnosis and therapy of human disorders. In particular, the rational design of amino functionalized luminescent silica coated QD nanoparticles (QD@SiO2 NPs) provides a versatile nanoplatform to anchor a potent and selective TSPO ligand, characterized by a 2-phenyl-imidazo[1,2-a]pyridine acetamide structure along with a derivatizable carboxylic end group, useful to conjugate the TSPO ligand and achieve TSPO-QD@SiO2 NPs by means of a covalent amide bond. The colloidal stability and optical properties of the proposed nanomaterials are comprehensively investigated and their potential as mitochondrial imaging agents is fully assessed. Sub-cellular fractionation, together with confocal laser scanning fluorescence microscopy and co-localization analysis of targeted TSPO-QD@SiO2 NPs in C6 glioma cells overexpressing the TSPO, proves the great potential of these multifunctional nanosystems as in vitro selective mitochondrial imaging agents.
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Affiliation(s)
- E Fanizza
- Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona 4, 70126 Bari, Italy
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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.
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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.
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Zhao AH, Tu LN, Mukai C, Sirivelu MP, Pillai VV, Morohaku K, Cohen R, Selvaraj V. Mitochondrial Translocator Protein (TSPO) Function Is Not Essential for Heme Biosynthesis. J Biol Chem 2015; 291:1591-1603. [PMID: 26627829 DOI: 10.1074/jbc.m115.686360] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 01/08/2023] Open
Abstract
Function of the mammalian translocator protein (TSPO; previously known as the peripheral benzodiazepine receptor) remains unclear because its presumed role in steroidogenesis and mitochondrial permeability transition established using pharmacological methods has been refuted in recent genetic studies. Protoporphyrin IX (PPIX) is considered a conserved endogenous ligand for TSPO. In bacteria, TSPO was identified to regulate tetrapyrrole metabolism and chemical catalysis of PPIX in the presence of light, and in vertebrates, TSPO function has been linked to porphyrin transport and heme biosynthesis. Positive correlation between high TSPO expression in cancer cells and susceptibility to photodynamic therapy based on their increased ability to convert the precursor 5-aminolevulinic acid (ALA) to PPIX appeared to reinforce this mechanism. In this study, we used TSPO knock-out (Tspo(-/-)) mice, primary cells, and different tumor cell lines to examine the role of TSPO in erythropoiesis, heme levels, PPIX biosynthesis, phototoxic cell death, and mitochondrial bioenergetic homeostasis. In contrast to expectations, our results demonstrate that TSPO deficiency does not adversely affect erythropoiesis, heme biosynthesis, bioconversion of ALA to PPIX, and porphyrin-mediated phototoxic cell death. TSPO expression levels in cancer cells do not correlate with their ability to convert ALA to PPIX. In fibroblasts, we observed that TSPO deficiency decreased the oxygen consumption rate and mitochondrial membrane potential (ΔΨm) indicative of a cellular metabolic shift, without a negative impact on porphyrin biosynthetic capability. Based on these findings, we conclude that mammalian TSPO does not have a critical physiological function related to PPIX and heme biosynthesis.
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Affiliation(s)
- Amy H Zhao
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Chinatsu Mukai
- the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | - Madhu P Sirivelu
- the Department of Clinical Pathology, College of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Viju V Pillai
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Roy Cohen
- the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853,.
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Leneveu-Jenvrin C, Bouffartigues E, Maillot O, Cornelis P, Feuilloley MGJ, Connil N, Chevalier S. Expression of the translocator protein (TSPO) from Pseudomonas fluorescens Pf0-1 requires the stress regulatory sigma factors AlgU and RpoH. Front Microbiol 2015; 6:1023. [PMID: 26441945 PMCID: PMC4585239 DOI: 10.3389/fmicb.2015.01023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/08/2015] [Indexed: 11/19/2022] Open
Abstract
The translocator protein (TSPO), previously designated as peripheral-type benzodiazepine receptor, is an evolutionary conserved protein that is found in many Eukarya, Archae, and Bacteria, in which it plays several important functions including for example membrane biogenesis, signaling, and stress response. A tspo homolog gene has been identified in several members of the Pseudomonas genus, among which the soil bacterium P. fluorescens Pf0-1. In this bacterium, the tspo gene is located in the vicinity of a putative hybrid histidine kinase-encoding gene. Since tspo has been involved in water stress related response in plants, we explored the effects of hyperosmolarity and temperature on P. fluorescens Pf0-1 tspo expression using a strategy based on lux-reporter fusions. We show that the two genes Pfl01_2810 and tspo are co-transcribed forming a transcription unit. The expression of this operon is growth phase-dependent and is increased in response to high concentrations of NaCl, sucrose and to a D-cycloserine treatment, which are conditions leading to activity of the major cell wall stress responsive extracytoplasmic sigma factor AlgU. Interestingly, the promoter region activity is strongly lowered in a P. aeruginosa algU mutant, suggesting that AlgU may be involved at least partly in the molecular mechanism leading to Pfl01_2810-tspo expression. In silico analysis of this promoter region failed to detect an AlgU consensus binding site; however, a putative binding site for the heat shock response RpoH sigma factor was detected. Accordingly, the promoter activity of the region containing this sequence is increased in response to high growth temperature and slightly lowered in a P. aeruginosa rpoH mutant strain. Taken together, our data suggest that P. fluorescens tspo gene may belong at least partly to the cell wall stress response.
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Affiliation(s)
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
| | - Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
| | - Nathalie Connil
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen Evreux, France
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SONG WEI, WANG WEI, WANG YU, DOU LIYANG, CHEN LIANFENG, YAN XIAOWEI. Characterization of fluorescent NBD-cholesterol efflux in THP-1-derived macrophages. Mol Med Rep 2015; 12:5989-96. [DOI: 10.3892/mmr.2015.4154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 06/26/2015] [Indexed: 11/06/2022] Open
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Enigmatic Translocator protein (TSPO) and cellular stress regulation. Trends Biochem Sci 2015; 40:497-503. [PMID: 26228316 DOI: 10.1016/j.tibs.2015.07.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/25/2015] [Accepted: 07/06/2015] [Indexed: 11/23/2022]
Abstract
Translocator proteins (TSPOs) are conserved, ubiquitous membrane proteins identified initially as benzodiazepine-binding proteins in mammalian cells. Recent genetic and biochemical studies have challenged the accepted model that TSPOs are essential and required for steroidogenesis in animal cells. Instead, evidence from different kingdoms of life suggests that TSPOs are encoded by nonessential genes that are temporally upregulated in cells encountering conditions of oxidative stress, including inflammation and tissue injury. Here we discuss how TSPOs may be involved in complex homeostasis signaling mechanisms. We suggest that the main physiological role of TSPOs may be to modulate oxidative stress, irrespective of the cell type or subcellular localization, in part through the subtle regulation of tetrapyrrole metabolism.
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Hachez C, Veljanovski V, Reinhardt H, Guillaumot D, Vanhee C, Chaumont F, Batoko H. The Arabidopsis abiotic stress-induced TSPO-related protein reduces cell-surface expression of the aquaporin PIP2;7 through protein-protein interactions and autophagic degradation. THE PLANT CELL 2014; 26:4974-90. [PMID: 25538184 PMCID: PMC4311218 DOI: 10.1105/tpc.114.134080] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 11/27/2014] [Accepted: 12/03/2014] [Indexed: 05/18/2023]
Abstract
The Arabidopsis thaliana multi-stress regulator TSPO is transiently induced by abiotic stresses. The final destination of this polytopic membrane protein is the Golgi apparatus, where its accumulation is strictly regulated, and TSPO is downregulated through a selective autophagic pathway. TSPO-related proteins regulate the physiology of the cell by generating functional protein complexes. A split-ubiquitin screen for potential TSPO interacting partners uncovered a plasma membrane aquaporin, PIP2;7. Pull-down assays and fluorescence imaging approaches revealed that TSPO physically interacts with PIP2;7 at the endoplasmic reticulum and Golgi membranes in planta. Intriguingly, constitutive expression of fluorescently tagged PIP2;7 in TSPO-overexpressing transgenic lines resulted in patchy distribution of the fluorescence, reminiscent of the pattern of constitutively expressed yellow fluorescent protein-TSPO in Arabidopsis. Mutational stabilization of TSPO or pharmacological inhibition of the autophagic pathway affected concomitantly the detected levels of PIP2;7, suggesting that the complex containing both proteins is degraded through the autophagic pathway. Coexpression of TSPO and PIP2;7 resulted in decreased levels of PIP2;7 in the plasma membrane and abolished the membrane water permeability mediated by transgenic PIP2;7. Taken together, these data support a physiological role for TSPO in regulating the cell-surface expression of PIP2;7 during abiotic stress conditions through protein-protein interaction and demonstrate an aquaporin regulatory mechanism involving TSPO.
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Affiliation(s)
- Charles Hachez
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Vasko Veljanovski
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Hagen Reinhardt
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Damien Guillaumot
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Celine Vanhee
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - François Chaumont
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Institut des Sciences de la Vie, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
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46
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Banati RB, Middleton RJ, Chan R, Hatty CR, Wai-Ying Kam W, Quin C, Graeber MB, Parmar A, Zahra D, Callaghan P, Fok S, Howell NR, Gregoire M, Szabo A, Pham T, Davis E, Liu GJ. Positron emission tomography and functional characterization of a complete PBR/TSPO knockout. Nat Commun 2014; 5:5452. [PMID: 25406832 PMCID: PMC4263137 DOI: 10.1038/ncomms6452] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/01/2014] [Indexed: 12/17/2022] Open
Abstract
The evolutionarily conserved peripheral benzodiazepine receptor (PBR), or 18-kDa translocator protein (TSPO), is thought to be essential for cholesterol transport and steroidogenesis, and thus life. TSPO has been proposed as a biomarker of neuroinflammation and a new drug target in neurological diseases ranging from Alzheimer's disease to anxiety. Here we show that global C57BL/6-Tspo(tm1GuWu(GuwiyangWurra))-knockout mice are viable with normal growth, lifespan, cholesterol transport, blood pregnenolone concentration, protoporphyrin IX metabolism, fertility and behaviour. However, while the activation of microglia after neuronal injury appears to be unimpaired, microglia from (GuwiyangWurra)TSPO knockouts produce significantly less ATP, suggesting reduced metabolic activity. Using the isoquinoline PK11195, the ligand originally used for the pharmacological and structural characterization of the PBR/TSPO, and the imidazopyridines CLINDE and PBR111, we demonstrate the utility of (GuwiyangWurra)TSPO knockouts to provide robust data on drug specificity and selectivity, both in vitro and in vivo, as well as the mechanism of action of putative TSPO-targeting drugs.
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Affiliation(s)
- Richard B. Banati
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- National Imaging Facility, Sydney, Camperdown, New South Wales 2006, Australia
| | - Ryan J. Middleton
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Ronald Chan
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Claire R. Hatty
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Winnie Wai-Ying Kam
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Candice Quin
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Manuel B. Graeber
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Arvind Parmar
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - David Zahra
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Paul Callaghan
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Sandra Fok
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nicholas R. Howell
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Marie Gregoire
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Alexander Szabo
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
- Centre for Translational Neuroscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Tien Pham
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Emma Davis
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Guo-Jun Liu
- Life Sciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
- Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
- Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
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Hinsen K, Vaitinadapoule A, Ostuni MA, Etchebest C, Lacapere JJ. Construction and validation of an atomic model for bacterial TSPO from electron microscopy density, evolutionary constraints, and biochemical and biophysical data. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:568-80. [PMID: 25450341 DOI: 10.1016/j.bbamem.2014.10.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/01/2014] [Accepted: 10/20/2014] [Indexed: 11/30/2022]
Abstract
The 18 kDa protein TSPO is a highly conserved transmembrane protein found in bacteria, yeast, animals and plants. TSPO is involved in a wide range of physiological functions, among which the transport of several molecules. The atomic structure of monomeric ligand-bound mouse TSPO in detergent has been published recently. A previously published low-resolution structure of Rhodobacter sphaeroides TSPO, obtained from tubular crystals with lipids and observed in cryo-electron microscopy, revealed an oligomeric structure without any ligand. We analyze this electron microscopy density in view of available biochemical and biophysical data, building a matching atomic model for the monomer and then the entire crystal. We compare its intra- and inter-molecular contacts with those predicted by amino acid covariation in TSPO proteins from evolutionary sequence analysis. The arrangement of the five transmembrane helices in a monomer of our model is different from that observed for the mouse TSPO. We analyze possible ligand binding sites for protoporphyrin, for the high-affinity ligand PK 11195, and for cholesterol in TSPO monomers and/or oligomers, and we discuss possible functional implications.
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Affiliation(s)
- Konrad Hinsen
- Centre de Biophysique Moléculaire (CNRS), Rue Charles Sadron, 45071 Orléans Cedex, France; Synchrotron SOLEIL, Division Expériences, Saint Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex, France.
| | - Aurore Vaitinadapoule
- INSERM, UMR-S1134, 6 rue Alexandre Cabanel, Université Paris 7 Denis Diderot, F-75015 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France; Institut National de la Transfusion Sanguine (INTS), Paris, France; GR-Ex, Laboratoire d'Excellence, Paris, France; National Centre for Biological Sciences (NCBS), Tata Institute for Fundamental Research, GKVK Campus, Bangalore, Karnataka, India; Dynamique des Structures et des Interactions des des Macromolécules Biologiques, France.
| | - Mariano A Ostuni
- INSERM, UMR-S1134, 6 rue Alexandre Cabanel, Université Paris 7 Denis Diderot, F-75015 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France; Institut National de la Transfusion Sanguine (INTS), Paris, France; GR-Ex, Laboratoire d'Excellence, Paris, France.
| | - Catherine Etchebest
- INSERM, UMR-S1134, 6 rue Alexandre Cabanel, Université Paris 7 Denis Diderot, F-75015 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France; Institut National de la Transfusion Sanguine (INTS), Paris, France; GR-Ex, Laboratoire d'Excellence, Paris, France; Dynamique des Structures et des Interactions des des Macromolécules Biologiques, France.
| | - Jean-Jacques Lacapere
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Biomolécules (LBM), 4 Place Jussieu, F-75005 Paris, France; Ecole Normale Supérieure - PSL Research University, Département de Chimie, 24, rue Lhomond, 75005 Paris, France; CNRS, UMR 7203 LBM, F-75005 Paris, France.
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48
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Tu LN, Morohaku K, Manna PR, Pelton SH, Butler WR, Stocco DM, Selvaraj V. Peripheral benzodiazepine receptor/translocator protein global knock-out mice are viable with no effects on steroid hormone biosynthesis. J Biol Chem 2014; 289:27444-54. [PMID: 24936060 PMCID: PMC4183784 DOI: 10.1074/jbc.m114.578286] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 05/30/2014] [Indexed: 01/19/2023] Open
Abstract
Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is a mitochondrial outer membrane protein implicated as essential for cholesterol import to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Previous research on TSPO was based entirely on in vitro experiments, and its critical role was reinforced by an early report that claimed TSPO knock-out mice were embryonic lethal. In a previous publication, we examined Leydig cell-specific TSPO conditional knock-out mice that suggested TSPO was not required for testosterone production in vivo. This raised controversy and several questions regarding TSPO function. To examine the definitive role of TSPO in steroidogenesis and embryo development, we generated global TSPO null (Tspo(-/-)) mice. Contrary to the early report, Tspo(-/-) mice survived with no apparent phenotypic abnormalities and were fertile. Examination of adrenal and gonadal steroidogenesis showed no defects in Tspo(-/-) mice. Adrenal transcriptome comparison of gene expression profiles showed that genes involved in steroid hormone biosynthesis (Star, Cyp11a1, and Hsd3b1) were unchanged in Tspo(-/-) mice. Adrenocortical ultrastructure illustrated no morphological alterations in Tspo(-/-) mice. In an attempt to correlate our in vivo findings to previously used in vitro models, we also determined that siRNA knockdown or the absence of TSPO in different mouse and human steroidogenic cell lines had no effect on steroidogenesis. These findings directly refute the dogma that TSPO is indispensable for steroid hormone biosynthesis and viability. By amending the current model, this study advances our understanding of steroidogenesis with broad implications in biology and medicine.
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Affiliation(s)
- Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Pulak R Manna
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Susanne H Pelton
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - W Ronald Butler
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Douglas M Stocco
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
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49
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Tu LN, Morohaku K, Manna PR, Pelton SH, Butler WR, Stocco DM, Selvaraj V. Peripheral benzodiazepine receptor/translocator protein global knock-out mice are viable with no effects on steroid hormone biosynthesis. J Biol Chem 2014. [PMID: 24936060 DOI: 10.10784/jbc.m114.578286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is a mitochondrial outer membrane protein implicated as essential for cholesterol import to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Previous research on TSPO was based entirely on in vitro experiments, and its critical role was reinforced by an early report that claimed TSPO knock-out mice were embryonic lethal. In a previous publication, we examined Leydig cell-specific TSPO conditional knock-out mice that suggested TSPO was not required for testosterone production in vivo. This raised controversy and several questions regarding TSPO function. To examine the definitive role of TSPO in steroidogenesis and embryo development, we generated global TSPO null (Tspo(-/-)) mice. Contrary to the early report, Tspo(-/-) mice survived with no apparent phenotypic abnormalities and were fertile. Examination of adrenal and gonadal steroidogenesis showed no defects in Tspo(-/-) mice. Adrenal transcriptome comparison of gene expression profiles showed that genes involved in steroid hormone biosynthesis (Star, Cyp11a1, and Hsd3b1) were unchanged in Tspo(-/-) mice. Adrenocortical ultrastructure illustrated no morphological alterations in Tspo(-/-) mice. In an attempt to correlate our in vivo findings to previously used in vitro models, we also determined that siRNA knockdown or the absence of TSPO in different mouse and human steroidogenic cell lines had no effect on steroidogenesis. These findings directly refute the dogma that TSPO is indispensable for steroid hormone biosynthesis and viability. By amending the current model, this study advances our understanding of steroidogenesis with broad implications in biology and medicine.
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Affiliation(s)
- Lan N Tu
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Kanako Morohaku
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Pulak R Manna
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Susanne H Pelton
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - W Ronald Butler
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
| | - Douglas M Stocco
- the Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Vimal Selvaraj
- From the Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853 and
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Lin R, Angelin A, Da Settimo F, Martini C, Taliani S, Zhu S, Wallace DC. Genetic analysis of dTSPO, an outer mitochondrial membrane protein, reveals its functions in apoptosis, longevity, and Ab42-induced neurodegeneration. Aging Cell 2014; 13:507-18. [PMID: 24977274 PMCID: PMC4076708 DOI: 10.1111/acel.12200] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The outer mitochondrial membrane (OMM) protein, the translocator protein 18 kDa (TSPO), formerly named the peripheral benzodiazepine receptor (PBR), has been proposed to participate in the pathogenesis of neurodegenerative diseases. To clarify the TSPO function, we identified the Drosophila homolog, CG2789/dTSPO, and studied the effects of its inactivation by P-element insertion, RNAi knockdown, and inhibition by ligands (PK11195, Ro5-4864). Inhibition of dTSPO inhibited wing disk apoptosis in response to γ-irradiation or H2O2 exposure, as well as extended male fly lifespan and inhibited Aβ42-induced neurodegeneration in association with decreased caspase activation. Therefore, dTSPO is an essential mediator of apoptosis in Drosophila and plays a central role in controlling longevity and neurodegenerative disease, making it a promising drug target.
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Affiliation(s)
- Ran Lin
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | - Alessia Angelin
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | | | - Claudia Martini
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Sabrina Taliani
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Shigong Zhu
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
- Department of Pathology and Laboratory Medicine Perelman School of Medicine University of Pennsylvania Philadelphia PA 19104USA
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