1
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Li Y, Chen L, Papadopoulos V. The mitochondrial translocator protein (TSPO, 18 kDa): A key multifunctional molecule in liver diseases. Biochimie 2024; 224:91-103. [PMID: 38065288 DOI: 10.1016/j.biochi.2023.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/23/2023] [Accepted: 11/29/2023] [Indexed: 08/23/2024]
Abstract
Translocator protein (TSPO, 18 kDa), previously known as peripheral-type benzodiazepine receptor, is an evolutionarily conserved and tryptophan-rich 169-amino-acid protein located on the outer mitochondrial membrane. TSPO plays a crucial role in various fundamental physiological functions and cellular processes. Its expression is altered in pathological conditions, thus rendering TSPO a potential tool for diagnostic imaging and an appealing therapeutic target. The investigation of synthetic TSPO ligands as both agonists and antagonists has provided valuable insights into the regulatory mechanisms and functional properties of TSPO. Recently, accumulating evidence has highlighted the significance of TSPO in liver diseases. However, a comprehensive summary of TSPO function in the normal liver and diverse liver diseases is lacking. This review aims to provide an overview of recent advances in understanding TSPO function in both normal liver cells and various liver diseases, with a particular emphasis on its involvement in liver fibrosis and inflammation and addresses the existing knowledge gaps in the field that require further investigation.
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Affiliation(s)
- Yuchang Li
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA.
| | - Liting Chen
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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2
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Gouilly D, Saint-Aubert L, Ribeiro MJ, Salabert AS, Tauber C, Péran P, Arlicot N, Pariente J, Payoux P. Neuroinflammation PET imaging of the translocator protein (TSPO) in Alzheimer's disease: an update. Eur J Neurosci 2022; 55:1322-1343. [PMID: 35083791 DOI: 10.1111/ejn.15613] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/28/2022]
Abstract
Neuroinflammation is a significant contributor to Alzheimer's disease (AD). Until now, PET imaging of the translocator protein (TSPO) has been widely used to depict the neuroimmune endophenotype of AD. The aim of this review was to provide an update to the results from 2018 and to advance the characterization of the biological basis of TSPO imaging in AD by re-examining TSPO function and expression and the methodological aspects of interest. Although the biological basis of the TSPO PET signal is obviously related to microglia and astrocytes in AD, the observed process remains uncertain and might not be directly related to neuroinflammation. Further studies are required to re-examine the cellular significance underlying a variation in the PET signal in AD and how it can be impacted by a disease-modifying treatment.
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Affiliation(s)
- Dominique Gouilly
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Laure Saint-Aubert
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Maria-Joao Ribeiro
- Department of Nuclear Medicine, CHU, Tours, France.,UMR 1253, iBrain, Université de Tours, France.,Inserm CIC 1415, CHRU, Tours, France
| | - Anne-Sophie Salabert
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Nuclear Medicine, CHU, Toulouse, France
| | | | - Patrice Péran
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Nicolas Arlicot
- UMR 1253, iBrain, Université de Tours, France.,Inserm CIC 1415, CHRU, Tours, France
| | - Jérémie Pariente
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU, Toulouse, France.,Center of Clinical Investigations (CIC1436), CHU, Toulouse, France
| | - Pierre Payoux
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Nuclear Medicine, CHU, Toulouse, France
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3
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Nguyen HT, Najih M, Martin LJ. The AP-1 family of transcription factors are important regulators of gene expression within Leydig cells. Endocrine 2021; 74:498-507. [PMID: 34599696 DOI: 10.1007/s12020-021-02888-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Members of the AP-1 family of transcription factors are immediate early genes being modulated by different extracellular signals. The aim of this review is to highlight the important roles of AP-1 members in transcriptional regulation of genes important for testicular Leydig cell function and male testosterone production. METHODS A search of the relevant literature was performed in Google Scholar and NCBI Pubmed for AP-1 members and Leydig cells. Additional information was accessed from references of relevant articles. Only primary data from original peer-reviewed articles was considered for this review. RESULTS Different signaling pathways important for Leydig cells' functions are involved in the regulation of the activity of AP-1 members. These transcription factors participate in the regulation of genes related to different biological processes important for Leydig cells. CONCLUSIONS We conclude that members of the AP-1 family of transcription factors play critical roles in the regulation of Leydig cell proliferation, steroidogenesis, and cell-to-cell communication.
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Affiliation(s)
- Ha Tuyen Nguyen
- Biology Department, Université de Moncton, Moncton, NB, E1A 3E9, Canada
| | - Mustapha Najih
- Biology Department, Université de Moncton, Moncton, NB, E1A 3E9, Canada
| | - Luc J Martin
- Biology Department, Université de Moncton, Moncton, NB, E1A 3E9, Canada.
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4
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Frison M, Faccenda D, Abeti R, Rigon M, Strobbe D, England-Rendon BS, Cash D, Barnes K, Sadeghian M, Sajic M, Wells LA, Xia D, Giunti P, Smith K, Mortiboys H, Turkheimer FE, Campanella M. The translocator protein (TSPO) is prodromal to mitophagy loss in neurotoxicity. Mol Psychiatry 2021; 26:2721-2739. [PMID: 33664474 PMCID: PMC8505241 DOI: 10.1038/s41380-021-01050-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 01/13/2021] [Accepted: 02/05/2021] [Indexed: 12/14/2022]
Abstract
Dysfunctional mitochondria characterise Parkinson's Disease (PD). Uncovering etiological molecules, which harm the homeostasis of mitochondria in response to pathological cues, is therefore pivotal to inform early diagnosis and therapy in the condition, especially in its idiopathic forms. This study proposes the 18 kDa Translocator Protein (TSPO) to be one of those. Both in vitro and in vivo data show that neurotoxins, which phenotypically mimic PD, increase TSPO to enhance cellular redox-stress, susceptibility to dopamine-induced cell death, and repression of ubiquitin-dependent mitophagy. TSPO amplifies the extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) signalling, forming positive feedback, which represses the transcription factor EB (TFEB) and the controlled production of lysosomes. Finally, genetic variances in the transcriptome confirm that TSPO is required to alter the autophagy-lysosomal pathway during neurotoxicity.
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Affiliation(s)
- Michele Frison
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
- MRC Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Danilo Faccenda
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Rosella Abeti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square London, United Kingdom
| | - Manuel Rigon
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy
| | - Daniela Strobbe
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy
| | - Britannie S England-Rendon
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, Institute of Psychiatry, King's College London, Camberwell, United Kingdom
| | - Katy Barnes
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Mona Sadeghian
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Marija Sajic
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Lisa A Wells
- Imanova Limited, Centre for Imaging Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Dong Xia
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom
| | - Paola Giunti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square London, United Kingdom
| | - Kenneth Smith
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Heather Mortiboys
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, King's College London, Camberwell, United Kingdom
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street, London, United Kingdom.
- Department of Biology, University of Rome TorVergata, Via della Ricerca Scientifica, Rome, Italy.
- University College London Consortium for Mitochondrial Research, London, United Kingdom.
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5
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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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6
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Ammer LM, Vollmann-Zwerenz A, Ruf V, Wetzel CH, Riemenschneider MJ, Albert NL, Beckhove P, Hau P. The Role of Translocator Protein TSPO in Hallmarks of Glioblastoma. Cancers (Basel) 2020; 12:cancers12102973. [PMID: 33066460 PMCID: PMC7602186 DOI: 10.3390/cancers12102973] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/18/2022] Open
Abstract
Simple Summary The translocator protein (TSPO) has been under extensive investigation as a specific marker in positron emission tomography (PET) to visualize brain lesions following injury or disease. In recent years, TSPO is increasingly appreciated as a potential novel therapeutic target in cancer. In Glioblastoma (GBM), the most malignant primary brain tumor, TSPO expression levels are strongly elevated and scientific evidence accumulates, hinting at a pivotal role of TSPO in tumorigenesis and glioma progression. The aim of this review is to summarize the current literature on TSPO with respect to its role both in diagnostics and especially with regard to the critical hallmarks of cancer postulated by Hanahan and Weinberg. Overall, our review contributes to a better understanding of the functional significance of TSPO in Glioblastoma and draws attention to TSPO as a potential modulator of treatment response and thus an important factor that may influence the clinical outcome of GBM. Abstract Glioblastoma (GBM) is the most fatal primary brain cancer in adults. Despite extensive treatment, tumors inevitably recur, leading to an average survival time shorter than 1.5 years. The 18 kDa translocator protein (TSPO) is abundantly expressed throughout the body including the central nervous system. The expression of TSPO increases in states of inflammation and brain injury due to microglia activation. Not least due to its location in the outer mitochondrial membrane, TSPO has been implicated with a broad spectrum of functions. These include the regulation of proliferation, apoptosis, migration, as well as mitochondrial functions such as mitochondrial respiration and oxidative stress regulation. TSPO is frequently overexpressed in GBM. Its expression level has been positively correlated to WHO grade, glioma cell proliferation, and poor prognosis of patients. Several lines of evidence indicate that TSPO plays a functional part in glioma hallmark features such as resistance to apoptosis, invasiveness, and proliferation. This review provides a critical overview of how TSPO could regulate several aspects of tumorigenesis in GBM, particularly in the context of the hallmarks of cancer proposed by Hanahan and Weinberg in 2011.
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Affiliation(s)
- Laura-Marie Ammer
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Arabel Vollmann-Zwerenz
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Viktoria Ruf
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, 81377 Munich, Germany;
| | - Christian H. Wetzel
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany;
| | | | - Nathalie L. Albert
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, 81377 Munich, Germany;
| | - Philipp Beckhove
- Regensburg Center for Interventional Immunology (RCI) and Department Internal Medicine III, University Hospital Regensburg, 93053 Regensburg, Germany;
| | - Peter Hau
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
- Correspondence:
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7
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Shimoyama S, Furukawa T, Ogata Y, Nikaido Y, Koga K, Sakamoto Y, Ueno S, Nakamura K. Lipopolysaccharide induces mouse translocator protein (18 kDa) expression via the AP-1 complex in the microglial cell line, BV-2. PLoS One 2019; 14:e0222861. [PMID: 31536603 PMCID: PMC6752844 DOI: 10.1371/journal.pone.0222861] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023] Open
Abstract
It has been reported that neuroinflammation occurs in the central nervous system (CNS) in patients with neuropathic pain, Alzheimer’s disease and autism spectrum disorder. The 18-kDa translocator protein TSPO is used as an imaging target in positron emission tomography to detect neuroinflammation, and its expression is correlated with microglial activation. However, the mechanism underlying the transcriptional regulation of Tspo induced by inflammation is not clear. Here, we revealed that lipopolysaccharide (LPS) -induced Tspo expression was activated by the AP-1 complex in a mouse microglial cell line, BV-2. Knockdown of c-Fos and c-Jun, the components of AP-1, reduced LPS-induced Tspo expression. Furthermore, the enrichment of Sp1 in the proximal promoter region of Tspo was increased in the presence of LPS. In addition, the binding of histone deacetylase 1 (HDAC1) to the enhancer region, which contains the AP-1 site, was decreased by LPS treatment, but there were no significant differences in HDAC1 binding to the proximal promoter region with or without LPS. These results indicated that HDAC1 is involved not in the proximal promoter region but in the enhancer region. Our study revealed that inflammatory signals induce the recruitment of AP-1 to the enhancer region and Sp1 to the proximal promoter region of the Tspo gene and that Sp1 may regulate the basal expression of Tspo.
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Affiliation(s)
- Shuji Shimoyama
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yoshiki Ogata
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yoshikazu Nikaido
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kohei Koga
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yui Sakamoto
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Shinya Ueno
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kazuhiko Nakamura
- Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
- * E-mail:
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8
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Transcriptional regulation of Translocator protein (18 kDa) (TSPO) in microglia requires Pu.1, Ap1 and Sp factors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:1119-1133. [PMID: 30412797 DOI: 10.1016/j.bbagrm.2018.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/12/2018] [Accepted: 10/31/2018] [Indexed: 11/21/2022]
Abstract
Mitochondrial Translocator protein (18 kDa) (TSPO) is strongly expressed in reactive microglia and serves as a therapeutic target for alleviation of neuronal degeneration. However, little is known about TSPO's transcriptional regulation in microglia. The aim of this study was to identify genetic elements and transcription factors required for basal and inducible TSPO expression in microglia. Murine Tspo promoter was cloned into the pGL4.10 luciferase vector and functionally characterized in BV-2 cells. Deletion mutagenesis indicated that -845 bases upstream were sufficient to reconstitute near maximal promoter activity in BV-2. Deletion of -593 to -520 sequences, which harbour an Ap1, Ets.2 and Nkx3.1 site which also serves as a non-canonical binding site for Sp1-family transcription factors, led to a dramatic decrease in both basal and LPS induced promoter activity. Further deletion of -168 to -39 sequences, which contains four GC boxes, also led to a significant decrease in promoter activity. Targeted mutations of Ap1, Ets.2, Nkx3.1/Sp1/3/4 and the GC boxes led to significant decreases in promoter activity. ChIP-qPCR revealed that Pu.1, Ap1, Stat3, Sp1, Sp3 and Sp4 bind to the endogenous Tspo promoter. Notably, binding of these factors, with the exception of Stat3, was significantly enhanced upon LPS treatment. RNAi silencing of Pu.1, cJun, cFos, Sp1, Sp3, Sp4 and Stat3 strongly lowered Tspo promoter activity while Ap1 silencing inhibited LPS induced increase in Tspo protein levels. These findings demonstrate that consensus binding sequences for Ap1, Ets.2, distal as well as proximal Sp1/3/4 sites regulate basal and LPS induced Tspo promoter activity in microglia.
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9
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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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10
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TSPO: kaleidoscopic 18-kDa amid biochemical pharmacology, control and targeting of mitochondria. Biochem J 2016; 473:107-21. [PMID: 26733718 DOI: 10.1042/bj20150899] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The 18-kDa translocator protein (TSPO) localizes in the outer mitochondrial membrane (OMM) of cells and is readily up-regulated under various pathological conditions such as cancer, inflammation, mechanical lesions and neurological diseases. Able to bind with high affinity synthetic and endogenous ligands, its core biochemical function resides in the translocation of cholesterol into the mitochondria influencing the subsequent steps of (neuro-)steroid synthesis and systemic endocrine regulation. Over the years, however, TSPO has also been linked to core cellular processes such as apoptosis and autophagy. It interacts and forms complexes with other mitochondrial proteins such as the voltage-dependent anion channel (VDAC) via which signalling and regulatory transduction of these core cellular events may be influenced. Despite nearly 40 years of study, the precise functional role of TSPO beyond cholesterol trafficking remains elusive even though the recent breakthroughs on its high-resolution crystal structure and contribution to quality-control signalling of mitochondria. All this along with a captivating pharmacological profile provides novel opportunities to investigate and understand the significance of this highly conserved protein as well as contribute the development of specific therapeutics as presented and discussed in the present review.
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11
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Kanegawa N, Collste K, Forsberg A, Schain M, Arakawa R, Jucaite A, Lekander M, Olgart Höglund C, Kosek E, Lampa J, Halldin C, Farde L, Varrone A, Cervenka S. In vivo evidence of a functional association between immune cells in blood and brain in healthy human subjects. Brain Behav Immun 2016; 54:149-157. [PMID: 26820224 DOI: 10.1016/j.bbi.2016.01.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/27/2015] [Accepted: 01/23/2016] [Indexed: 11/24/2022] Open
Abstract
Microglia, the resident macrophages in the central nervous system, are thought to be maintained by a local self-renewal mechanism. Although preclinical and in vitro studies have suggested that the brain may contain immune cells also from peripheral origin, the functional association between immune cells in the periphery and brain at physiological conditions is poorly understood. We examined 32 healthy individuals using positron emission tomography (PET) and [(11)C]PBR28, a radioligand for the 18-kDa translocator protein (TSPO) which is expressed both in brain microglia and blood immune cells. In 26 individuals, two measurements were performed with varying time intervals. In a subgroup of 19 individuals, of which 12 had repeat examinations, leukocyte numbers in blood was measured on each day of PET measurements. All individuals were genotyped for TSPO polymorphism and categorized as high, mixed, and low affinity binders. We assessed TSPO binding expressed as total distribution volume of [(11)C]PBR28 in brain and in blood cells. TSPO binding in brain was strongly and positively correlated to binding in blood cells both at baseline and when analyzing change between two PET examinations. Furthermore, there was a significant correlation between change of leukocyte numbers and change in TSPO binding in brain, and a trend-level correlation to change in TSPO binding in blood cells. These in vivo findings indicate an association between immunological cells in blood and brain via intact BBB, suggesting a functional interaction between these two compartments, such as interchange of peripherally derived cells or a common regulatory mechanism. Measurement of radioligand binding in blood cells may be a way to control for peripheral immune function in PET studies using TSPO as a marker of brain immune activation.
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Affiliation(s)
- Naoki Kanegawa
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Karin Collste
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Anton Forsberg
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Martin Schain
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Ryosuke Arakawa
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Aurelija Jucaite
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Mats Lekander
- Department of Clinical Neuroscience, Osher Center for Integrative Medicine, Karolinska Institutet, Stockholm, Sweden; Stress Research Institute, Stockholm University, Stockholm, Sweden
| | - Caroline Olgart Höglund
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Department of Medicine Solna and CMM, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Eva Kosek
- Department of Clinical Neuroscience, Osher Center for Integrative Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jon Lampa
- Department of Medicine, Rheumatology Unit, Center of Molecular Medicine (CMM), Karolinska Institutet, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Andrea Varrone
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden
| | - Simon Cervenka
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet, Stockholm, Sweden.
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12
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Abstract
The mitochondrial 18-kDa translocator protein (TSPO) was originally discovered as a peripheral binding site of benzodiazepines to be later described as a core element of cholesterol trafficking between cytosol and mitochondria from which the current nomenclature originated. The high affinity it exhibits with chemicals (i.e. PK11195) has generated interest in the development of mitochondrial based TSPO-binding drugs for in vitro and in vivo analysis. Increased TSPO expression is observed in numerous pathologies such as cancer and inflammatory conditions of the central nervous system (CNS) that have been successfully exploited via protocols of positron emission tomography (PET) imaging. We endeavoured to dissect the molecular role of TSPO in mitochondrial cell biology and discovered a functional link with quality control mechanisms operated by selective autophagy. This review focuses on the current understanding of this pathway and focuses on the interplay with reactive oxygen species (ROS) and the voltage-dependent anion channel (VDAC), to which TSPO binds, in the regulation of cell mitophagy and hence homoeostasis of the mitochondrial network as a whole.
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Kuan CS, Yee YH, See Too WC, Few LL. Ets and GATA transcription factors play a critical role in PMA-mediated repression of the ckβ promoter via the protein kinase C signaling pathway. PLoS One 2014; 9:e113485. [PMID: 25490397 PMCID: PMC4260826 DOI: 10.1371/journal.pone.0113485] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 10/27/2014] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Choline kinase is the most upstream enzyme in the CDP-choline pathway. It catalyzes the phosphorylation of choline to phosphorylcholine in the presence of ATP and Mg2+ during the biosynthesis of phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. In humans, choline kinase (CK) is encoded by two separate genes, ckα and ckβ, which produce three isoforms, CKα1, CKα2, and CKβ. Previous studies have associated ckβ with muscle development; however, the molecular mechanism underlying the transcriptional regulation of ckβ has never been elucidated. METHODOLOGY/PRINCIPAL FINDINGS In this report, the distal promoter region of the ckβ gene was characterized. Mutational analysis of the promoter sequence and electrophoretic mobility shift assays (EMSA) showed that Ets and GATA transcription factors were essential for the repression of ckβ promoter activity. Supershift and chromatin immunoprecipitation (ChIP) assays further identified that GATA3 but not GATA2 was bound to the GATA site of ckβ promoter. In addition, phorbol-12-myristate-13-acetate (PMA) decreased ckβ promoter activity through Ets and GATA elements. PMA also decreased the ckβ mRNA and protein levels about 12 hours after the promoter activity was down-regulated. EMSA further revealed that PMA treatment increased the binding of both Ets and GATA transcription factors to their respective DNA elements. The PMA-mediated repressive effect was abolished by chronic PMA treatment and by treatment with the PKC inhibitor PKC412, but not the PKC inhibitor Go 6983, suggesting PKCε or PKCη as the PKC isozyme involved in the PMA-mediated repression of ckβ promoter. Further confirmation by using PKC isozyme specific inhibitors identified PKCε as the isozyme that mediated the PMA repression of ckβ promoter. CONCLUSION/SIGNIFICANCE These results demonstrate the participation of the PKC signaling pathway in the regulation of ckβ gene transcription by Ets and GATA transcription factors.
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Affiliation(s)
- Chee Sian Kuan
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Yoke Hiang Yee
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Wei Cun See Too
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Ling Ling Few
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
- * E-mail:
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Gatliff J, East D, Crosby J, Abeti R, Harvey R, Craigen W, Parker P, Campanella M. TSPO interacts with VDAC1 and triggers a ROS-mediated inhibition of mitochondrial quality control. Autophagy 2014; 10:2279-96. [PMID: 25470454 PMCID: PMC4502750 DOI: 10.4161/15548627.2014.991665] [Citation(s) in RCA: 152] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 09/17/2014] [Accepted: 09/22/2014] [Indexed: 01/03/2023] Open
Abstract
The 18-kDa TSPO (translocator protein) localizes on the outer mitochondrial membrane (OMM) and participates in cholesterol transport. Here, we report that TSPO inhibits mitochondrial autophagy downstream of the PINK1-PARK2 pathway, preventing essential ubiquitination of proteins. TSPO abolishes mitochondrial relocation of SQSTM1/p62 (sequestosome 1), and consequently that of the autophagic marker LC3 (microtubule-associated protein 1 light chain 3), thus leading to an accumulation of dysfunctional mitochondria, altering the appearance of the network. Independent of cholesterol regulation, the modulation of mitophagy by TSPO is instead dependent on VDAC1 (voltage-dependent anion channel 1), to which TSPO binds, reducing mitochondrial coupling and promoting an overproduction of reactive oxygen species (ROS) that counteracts PARK2-mediated ubiquitination of proteins. These data identify TSPO as a novel element in the regulation of mitochondrial quality control by autophagy, and demonstrate the importance for cell homeostasis of its expression ratio with VDAC1.
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Key Words
- ATP5B, ATP synthase, H+ transporting, mitochondrial F1 complex, β subunit
- DAPI, 4’, 6-diamidino-2-phenylindole
- DHE, dihydroethidium
- DNM1L, dynamin 1-like
- FCCP, carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GSH, glutathione
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MCB, monochlorobimane
- MEFs, mouse embryonic fibroblasts
- MnTBAP, manganese [III] tetrakis (4-benzoic acid) porphyrin
- MβCD, methyl-β-cyclodextrin
- NRF1, nuclear respiratory factor 1
- OMM, outer mitochondrial membrane
- PARK2
- PBS, phosphate-buffered saline
- PINK1, PTEN-induced putative kinase 1
- PRKCE, protein kinase C, epsilon
- RM, recording medium
- ROS
- ROS, reactive oxygen species
- RT, room temperature
- SQSTM1, sequestosome 1
- TFAM, transcription factor A, mitochondrial
- TMRM, tetramethylrhodamine methyl ester
- TSPO
- TSPO, translocator protein
- VDAC1, voltage-dependent anion channel 1
- YFP, yellow fluorescent protein
- mitochondria
- mitophagy
- mtRFP, mitochondrially targeted red fluorescent protein
- nsc, nonsilencing control
- siRNA, small interfering ribonucleic acid
- ubiquitin
- Δψm, mitochondrial membrane potential
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Affiliation(s)
- Jemma Gatliff
- Department of Comparative Biomedical Sciences; The Royal Veterinary College; University of London; London, UK
| | - Daniel East
- Department of Comparative Biomedical Sciences; The Royal Veterinary College; University of London; London, UK
| | - James Crosby
- Department of Comparative Biomedical Sciences; The Royal Veterinary College; University of London; London, UK
| | | | - Robert Harvey
- Department of Pharmacology; UCL School of Pharmacy; London, UK
| | - William Craigen
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston, TX USA
| | - Peter Parker
- London Research Institute; Lincoln's Inn Fields Laboratories; London, UK
- Division of Cancer Studies; King's College; London, UK
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences; The Royal Veterinary College; University of London; London, UK
- University College London Consortium for Mitochondrial Research; London, UK
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15
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Morohaku K, Phuong NS, Selvaraj V. Developmental expression of translocator protein/peripheral benzodiazepine receptor in reproductive tissues. PLoS One 2013; 8:e74509. [PMID: 24040265 PMCID: PMC3764105 DOI: 10.1371/journal.pone.0074509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/02/2013] [Indexed: 12/20/2022] Open
Abstract
Translocator protein (TSPO) present in the outer mitochondrial membrane has been suggested to be critical for cholesterol import, a rate-limiting step for steroid hormone biosynthesis. Despite the importance of steroidogenesis in regulating reproductive functions, the developmental profile of TSPO expression in the gonads and accessory sex organs has not been completely characterized. As a first step towards understanding the function of TSPO, we studied its expression in male and female murine reproductive organs. We examined testes and ovaries at embryonic days 14.5 and 18.5, and postnatal days 0, 7, 14, 21 and 56 of development. In the adult testis, TSPO was expressed in both Leydig cells and Sertoli cells. In the developing testes TSPO expression was seen in immature Sertoli cells, fetal Leydig cells and gonocytes. In the ovary, TSPO was expressed in the ovarian surface epithelium, interstitial cells granulosa cells and luteal cells. Corpora lutea of ovaries from pregnant mice showed strong expression of TSPO. In the developing ovary, TSPO expression was seen in the squamous pregranulosa cells associated with germ line cysts, together with progressively increasing expression in interstitial cells and the ovarian surface epithelium. In adult mice, the epithelia of other reproductive tissues like the epididymis, prostate, seminal vesicle, oviduct and uterus also showed distinct patterns of TSPO expression. In summary, TSPO expression in both male and female reproductive tissues was not only restricted to steroidogenic cells. Expression in Sertoli cells, ovarian surface epithelium, efferent ductal epithelium, prostatic epithelium, seminal vesiclular epithelium, uterine epithelium and oviductal epithelium suggest either previously unknown sites for de novo steroidogenesis or functions for TSPO distinct from its well-studied role in steroid hormone production.
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Affiliation(s)
- Kanako Morohaku
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
| | - Newton S. Phuong
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
| | - Vimal Selvaraj
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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16
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Fan J, Papadopoulos V. Transcriptional regulation of translocator protein (Tspo) via a SINE B2-mediated natural antisense transcript in MA-10 Leydig cells. Biol Reprod 2012; 86:147, 1-15. [PMID: 22378763 DOI: 10.1095/biolreprod.111.097535] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Translocator protein (18 kDa; TSPO) is a mitochondrial cholesterol- and drug-binding protein involved in cholesterol import into mitochondria, the rate-limiting step in steroidogenesis. TSPO is expressed at high levels in Leydig cells of the testis, and its expression levels dictate the ability of the cells to form androgen. In search of mechanisms that regulate Tspo expression, a number of transcription factors acting on its promoter region have been identified. We report herein the presence of a mechanism of regulation of Tspo expression via complementation with a natural antisense transcript (NAT). At the Tspo locus, a short interspersed repetitive element (SINE) of the SINE B2 family has the potential for high transcriptional activity. The extension of the SINE B2 element-mediated transcript overlapped with exon 3 of the Tspo gene and formed a NAT specific for Tspo (Tspo-NAT) in MA-10 mouse tumor Leydig cells. The identified Tspo-NAT was also found in testis and kidney tissues. Overexpression of the Tspo-NAT regulated Tspo gene expression and its function in steroid formation in MA-10 cells. Time-course studies have indicated that Tspo-NAT expression is regulated by cAMP and could regulate TSPO levels to maintain optimal steroid production by MA-10 Leydig cells. Taken together, these results suggest a new micro-transcriptional mechanism that regulates Tspo expression and thus steroidogenesis via an intron-based SINE B2-driven NAT specific for the Tspo gene.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre, McGill University, Montréal, Québec, Canada
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17
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Hattangady N, Olala L, Bollag WB, Rainey WE. Acute and chronic regulation of aldosterone production. Mol Cell Endocrinol 2012; 350:151-62. [PMID: 21839803 PMCID: PMC3253327 DOI: 10.1016/j.mce.2011.07.034] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 07/11/2011] [Accepted: 07/17/2011] [Indexed: 11/28/2022]
Abstract
Aldosterone is the major mineralocorticoid synthesized by the adrenal and plays an important role in the regulation of systemic blood pressure through the absorption of sodium and water. Aldosterone production is regulated tightly by selective expression of aldosterone synthase (CYP11B2) in the adrenal outermost zone, the zona glomerulosa. Angiotensin II (Ang II), potassium (K(+)) and adrenocorticotropin (ACTH) are the main physiological agonists which regulate aldosterone secretion. Aldosterone production is regulated within minutes of stimulation (acutely) through increased expression and phosphorylation of the steroidogenic acute regulatory (StAR) protein and over hours to days (chronically) by increased expression of the enzymes involved in the synthesis of aldosterone, particularly CYP11B2. Imbalance in any of these processes may lead to several disorders of aldosterone excess. In this review we attempt to summarize the key molecular events involved in the acute and chronic phases of aldosterone secretion.
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Affiliation(s)
- Namita Hattangady
- Department of Physiology, Georgia Health Sciences University (formerly the Medical College of Georgia), 1120 15 Street, Augusta, GA 30912
| | - Lawrence Olala
- Department of Physiology, Georgia Health Sciences University (formerly the Medical College of Georgia), 1120 15 Street, Augusta, GA 30912
| | - Wendy B. Bollag
- Department of Physiology, Georgia Health Sciences University (formerly the Medical College of Georgia), 1120 15 Street, Augusta, GA 30912
- Charlie Norwood VA Medical Center, One Freedom Way, Augusta, GA 30904
| | - William E. Rainey
- Department of Physiology, Georgia Health Sciences University (formerly the Medical College of Georgia), 1120 15 Street, Augusta, GA 30912
- To whom correspondence should be addressed: William E. Rainey, Department of Physiology, Georgia Health Sciences University, 1120 15 Street, Augusta, GA 30912, , Tel: (706) 721-7665, Fax: (706) 721-7299
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18
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Campioli E, Batarseh A, Li J, Papadopoulos V. The endocrine disruptor mono-(2-ethylhexyl) phthalate affects the differentiation of human liposarcoma cells (SW 872). PLoS One 2011; 6:e28750. [PMID: 22205965 PMCID: PMC3244402 DOI: 10.1371/journal.pone.0028750] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 11/14/2011] [Indexed: 01/04/2023] Open
Abstract
Esters of phthalic acid (phthalates) are largely used in industrial plastics, medical devices, and pharmaceutical formulations. They are easily released from plastics into the environment and can be found in measurable levels in human fluids. Phthalates are agonists for peroxisome proliferator-activated receptors (PPARs), through which they regulate translocator protein (TSPO; 18 kDa) transcription in a tissue-specific manner. TSPO is a drug- and cholesterol-binding protein involved in mitochondrial respiration, steroid formation, and cell proliferation. TSPO has been shown to increase during differentiation and decrease during maturation in mouse adipocytes. The purpose of this study was to establish the effect of mono-(2-ethylhexyl) phthalate (MEHP) on the differentiation of human SW 872 preadipocyte cells, and examine the role of TSPO in the process. After 4 days of treatment with 10 µM MEHP, we observed changes in the transcription of acetyl-CoA carboxylase alpha, adenosine triphosphate citrate lyase, glucose transporters 1 and 4, and the S100 calcium binding protein B, all of which are markers of preadipocyte differentiation. These observed gene expression changes coincided with a decrease in cellular proliferation without affecting cellular triglyceride content. Taken together, these data suggest that MEHP exerts a differentiating effect on human preadipocytes. Interestingly, MEHP was able to temporarily increase TSPO mRNA levels through the PPAR-α and β/δ pathways. These results suggest that TSPO can be considered an important player in the differentiation process itself, or alternatively a factor whose presence is essential for adipocyte development.
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Affiliation(s)
- Enrico Campioli
- Research Institute of the McGill University Health Center and the Departments of Medicine, Biochemistry, and Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Amani Batarseh
- Research Institute of the McGill University Health Center and the Departments of Medicine, Biochemistry, and Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Jiehan Li
- Research Institute of the McGill University Health Center and the Departments of Medicine, Biochemistry, and Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Center and the Departments of Medicine, Biochemistry, and Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
- * E-mail:
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19
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Inhibitory effects of wogonin on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-9. Toxicology 2011; 282:122-8. [DOI: 10.1016/j.tox.2011.01.018] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 01/24/2011] [Accepted: 01/25/2011] [Indexed: 01/13/2023]
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20
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Manna PR, Soh JW, Stocco DM. The involvement of specific PKC isoenzymes in phorbol ester-mediated regulation of steroidogenic acute regulatory protein expression and steroid synthesis in mouse Leydig cells. Endocrinology 2011; 152:313-25. [PMID: 21047949 PMCID: PMC3033061 DOI: 10.1210/en.2010-0874] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein kinase C (PKC) is a multigene family of serine/threonine kinases. PKC is involved in regulating adrenal and gonadal steroidogenesis; however, the functional relevance of the different PKC isoenzymes remains obscure. In this study, we demonstrate that MA-10 mouse Leydig tumor cells express several PKC isoforms to varying levels and that the activation of PKC signaling, by phorbol 12-myristate 13-acetate (PMA) elevated the expression and phosphorylation of PKCα, -δ, -ε, and -μ/protein kinase D (PKD). These responses coincided with the expression of the steroidogenic acute regulatory (StAR) protein and progesterone synthesis. Targeted silencing of PKCα, δ, and ε and PKD, using small interfering RNAs, resulted in deceases in basal and PMA-mediated StAR and steroid levels and demonstrated the importance of PKD in steroidogenesis. PKD was capable of controlling PMA and cAMP/PKA-mediated synergism involved in the steroidogenic response. Further studies pointed out that the regulatory events effected by PKD are associated with cAMP response element-binding protein (CREB) and c-Jun/c-Fos-mediated transcription of the StAR gene. Chromatin immunoprecipitation studies revealed that the activation of phosphorylated CREB, c-Jun, and c-Fos by PMA was correlated with in vivo protein-DNA interactions and the recruitment of CREB-binding protein, whereas knockdown of PKD suppressed the association of these factors with the StAR promoter. Ectopic expression of CREB-binding protein enhanced the trans-activation potential of CREB and c-Jun/c-Fos in StAR gene expression. Using EMSA, a -83/-67-bp region of the StAR promoter was shown to bind PKD-transfected MA-10 nuclear extract in a PMA-responsive manner, targeting CREB and c-Jun/c-Fos proteins. These findings provide evidence for the presence of multiple PKC isoforms and demonstrate the molecular events by which selective isozymes, especially PKD, influence PMA/PKC signaling involved in the regulation of the steroidogenic machinery in mouse Leydig cells.
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Affiliation(s)
- Pulak R Manna
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, USA
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21
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Batarseh A, Papadopoulos V. Regulation of translocator protein 18 kDa (TSPO) expression in health and disease states. Mol Cell Endocrinol 2010; 327:1-12. [PMID: 20600583 PMCID: PMC2922062 DOI: 10.1016/j.mce.2010.06.013] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 06/17/2010] [Indexed: 01/12/2023]
Abstract
Translocator protein (TSPO) is an 18 kDa high affinity cholesterol- and drug-binding protein found primarily in the outer mitochondrial membrane. Although TSPO is found in many tissue types, it is expressed at the highest levels under normal conditions in tissues that synthesize steroids. TSPO has been associated with cholesterol import into mitochondria, a key function in steroidogenesis, and directly or indirectly with multiple other cellular functions including apoptosis, cell proliferation, differentiation, anion transport, porphyrin transport, heme synthesis, and regulation of mitochondrial function. Aberrant expression of TSPO has been linked to multiple diseases, including cancer, brain injury, neurodegeneration, and ischemia-reperfusion injury. There has been an effort during the last decade to understand the mechanisms regulating tissue- and disease-specific TSPO expression and to identify pharmacological means to control its expression. This review focuses on the current knowledge regarding the chemicals, hormones, and molecular mechanisms regulating Tspo gene expression under physiological conditions in a tissue- and disease-specific manner. The results described here provide evidence that the PKCepsilon-ERK1/2-AP-1/STAT3 signal transduction pathway is the primary regulator of Tspo gene expression in normal and pathological tissues expressing high levels of TSPO.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
| | - Vassilios Papadopoulos
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA
- The Research Institute of the McGill University Health Centre and the Department of Medicine, Biochemistry, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
- Department of Pharmacology and Therapeutics, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada
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22
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Ostuni MA, Issop L, Péranzi G, Walker F, Fasseu M, Elbim C, Papadopoulos V, Lacapere JJ. Overexpression of translocator protein in inflammatory bowel disease: potential diagnostic and treatment value. Inflamm Bowel Dis 2010; 16:1476-87. [PMID: 20222126 PMCID: PMC2930116 DOI: 10.1002/ibd.21250] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Inflammatory bowel diseases (IBDs), such as ulcerative colitis and Crohn's disease, are chronic inflammatory disorders that increase the risk for colorectal cancer. The mitochondrial translocator protein (TSPO) is a high-affinity drug- and cholesterol-binding protein expressed in the colon and its expression is increased in colon cancers. The aim of this study was to investigate TSPO expression in IBD biopsies and to establish an animal model of IBD to examine the role of TSPO. In addition, we evaluated the potential use of TSPO drug ligands in diagnosing and treating IBD. METHODS TSPO expression in IBD biopsies was evaluated using immunohistochemistry. IBD was induced in a rat experimental model via treatment with dextran sodium sulfate (DSS). Colon morphology, TSPO expression, and proinflammatory cytokine production were evaluated in addition to the effect of TSPO drug ligands on disease pathology. RESULTS TSPO protein levels were elevated in the enterocytes of IBD biopsies. TSPO expression was localized to the enterocyte mitochondria. DSS treatment induced a time-dependent phenotype mimicking IBD with tissue injury and subsequent tissue regeneration. Coadministration of DSS and the TSPO drug ligands PK 11195 or Ro5-4864 increased both the rate of colon ulceration and regeneration, whereas administration of the TSPO drug ligand flunitrazepam partially prevented this pathology. These data correlated with changes in proinflammatory cytokine plasma levels, as well as increased cytokine production and secretion from the colon. CONCLUSIONS TSPO may serve as a marker of the IBD repair process, and TSPO drug ligands should be further evaluated for IBD treatment.
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Affiliation(s)
- Mariano A Ostuni
- Unité INSERM U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Université Paris 7 Denis Diderot, Paris, France.
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23
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Batarseh A, Li J, Papadopoulos V. Protein kinase C epsilon regulation of translocator protein (18 kDa) Tspo gene expression is mediated through a MAPK pathway targeting STAT3 and c-Jun transcription factors. Biochemistry 2010; 49:4766-78. [PMID: 20469933 DOI: 10.1021/bi100020e] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Translocator protein TSPO is an 18 kDa protein implicated in numerous cell functions and is highly expressed in secretory and glandular tissues, especially in steroidogenic cells. TSPO expression is altered in pathological conditions such as certain cancers and neurological diseases. In search of the factors regulating Tspo expression, we recently showed that high levels of TSPO in steroidogenic cells may be due to high constitutive expression of protein kinase Cepsilon (PKCepsilon), while phorbol 12-myristate 13-acetate (PMA) activation of PKCepsilon drives inducible TSPO expression in nonsteroidogenic cells, likely through activator protein 1 (AP1). In this study, we aimed to identify the signal transduction pathway through which PKCepsilon regulates Tspo gene expression. The MEK1/2 specific inhibitor U0126, but not NFkappaB inhibitors, reduced basal Tspo promoter activity in TSPO-rich steroidogenic cells (MA-10 Leydig), as well as basal and PMA-induced Tspo promoter levels in TSPO-poor nonsteroidogenic cells (NIH-3T3 fibroblasts). AP1 and signal transducer and activation of transcription 3 (STAT3) have binding sites in the Tspo promoter and are downstream targets of PKCepsilon and MAPK (Raf-1-ERK1/2) pathways. PKCepsilon overexpression induced STAT3 phosphorylation in NIH-3T3 cells, while PKCepsilon knockdown reduced STAT3 and c-Jun phosphorylation in Leydig cells. MEK1/2, ERK2, c-Jun, and STAT3 knockdown reduced Tspo mRNA and protein levels in Leydig cells. Additionally, Raf-1 reduced Tspo mRNA levels in the same cells. MEK1/2, c-Jun, and STAT3 knockdown also reduced basal as well as PMA-induced Tspo mRNA levels in NIH-3T3 cells. Together, these results demonstrate that PKCepsilon regulates Tspo gene expression through a MAPK (Raf-1-MEK1/2-ERK1/2) signal transduction pathway, acting at least in part through c-Jun and STAT3 transcription factors.
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Affiliation(s)
- Amani Batarseh
- Department of Biochemistry and Molecular and Cell Biology, Georgetown University Medical Center, Washington, DC 20057, USA
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24
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Cantley J, Burchfield JG, Pearson GL, Schmitz-Peiffer C, Leitges M, Biden TJ. Deletion of PKCepsilon selectively enhances the amplifying pathways of glucose-stimulated insulin secretion via increased lipolysis in mouse beta-cells. Diabetes 2009; 58:1826-34. [PMID: 19401415 PMCID: PMC2712791 DOI: 10.2337/db09-0132] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Insufficient insulin secretion is a hallmark of type 2 diabetes, and exposure of beta-cells to elevated lipid levels (lipotoxicity) contributes to secretory dysfunction. Functional ablation of protein kinase C epsilon (PKCepsilon) has been shown to improve glucose homeostasis in models of type 2 diabetes and, in particular, to enhance glucose-stimulated insulin secretion (GSIS) after lipid exposure. Therefore, we investigated the lipid-dependent mechanisms responsible for the enhanced GSIS after inactivation of PKCepsilon. RESEARCH DESIGN AND METHODS We cultured islets isolated from PKCepsilon knockout (PKCepsilonKO) mice in palmitate prior to measuring GSIS, Ca(2+) responses, palmitate esterification products, lipolysis, lipase activity, and gene expression. RESULTS The enhanced GSIS could not be explained by increased expression of another PKC isoform or by alterations in glucose-stimulated Ca(2+) influx. Instead, an upregulation of the amplifying pathways of GSIS in lipid-cultured PKCepsilonKO beta-cells was revealed under conditions in which functional ATP-sensitive K(+) channels were bypassed. Furthermore, we showed increased esterification of palmitate into triglyceride pools and an enhanced rate of lipolysis and triglyceride lipase activity in PKCepsilonKO islets. Acute treatment with the lipase inhibitor orlistat blocked the enhancement of GSIS in lipid-cultured PKCepsilonKO islets, suggesting that a lipolytic product mediates the enhancement of glucose-amplified insulin secretion after PKCepsilon deletion. CONCLUSIONS Our findings demonstrate a mechanistic link between lipolysis and the amplifying pathways of GSIS in murine beta-cells, and they suggest an interaction between PKCepsilon and lipolysis. These results further highlight the therapeutic potential of PKCepsilon inhibition to enhance GSIS from the beta-cell under conditions of lipid excess.
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Affiliation(s)
- James Cantley
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - James G. Burchfield
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Gemma L. Pearson
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Carsten Schmitz-Peiffer
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales, Australia
| | - Michael Leitges
- Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway
| | - Trevor J. Biden
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales, Australia
- Corresponding author: Trevor Biden,
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