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Li X, Ramos-Rolón AP, Kass G, Pereira-Rufino LS, Shifman N, Shi Z, Volkow ND, Wiers CE. Imaging neuroinflammation in individuals with substance use disorders. J Clin Invest 2024; 134:e172884. [PMID: 38828729 PMCID: PMC11142750 DOI: 10.1172/jci172884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Increasing evidence suggests a role of neuroinflammation in substance use disorders (SUDs). This Review presents findings from neuroimaging studies assessing brain markers of inflammation in vivo in individuals with SUDs. Most studies investigated the translocator protein 18 kDa (TSPO) using PET; neuroimmune markers myo-inositol, choline-containing compounds, and N-acetyl aspartate using magnetic resonance spectroscopy; and fractional anisotropy using MRI. Study findings have contributed to a greater understanding of neuroimmune function in the pathophysiology of SUDs, including its temporal dynamics (i.e., acute versus chronic substance use) and new targets for SUD treatment.
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Affiliation(s)
- Xinyi Li
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
| | - Astrid P. Ramos-Rolón
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
| | - Gabriel Kass
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
| | - Lais S. Pereira-Rufino
- Departamento de Morfologia e Genética, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Naomi Shifman
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
| | - Zhenhao Shi
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
| | - Nora D. Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland, USA
| | - Corinde E. Wiers
- Center for Studies of Addiction, University of Pennsylvania Perelman School of Medicine, Department of Psychiatry, Philadelphia, Pennsylvania, USA
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2
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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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3
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Zhang Y, Xiao T, Wen M, Shen L, Du L, Wei S, Wu B, Yu Y, Wang S, OuYang B. Deciphering Cholesterol's Role in PD-L2 Stability: A Distinct Regulatory Mechanism From PD-L1. J Mol Biol 2024; 436:168500. [PMID: 38401626 DOI: 10.1016/j.jmb.2024.168500] [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: 11/22/2023] [Revised: 02/08/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024]
Abstract
Programmed cell death 1 ligand 2 (PD-L2), a member of the B7 immune checkpoint protein family, emerges as a crucial player in immune modulation. Despite its functional overlap with programmed cell death 1 ligand 1 (PD-L1) in binding to the programmed cell death protein 1 (PD-1) on T cells, PD-L2 exhibits a divergent expression pattern and a higher affinity for PD-1. However, the regulatory mechanisms of PD-L2 remain under-explored. Here, our investigations illustrate the pivotal role of cholesterol in modulating PD-L2 stability. Using advanced nuclear magnetic resonance (NMR) and biochemical analyses, we demonstrate a direct and specific binding between cholesterol and PD-L2, mediated by an F-xxx-V-xx-LR motif in its transmembrane domain, distinct from that in PD-L1. This interaction stabilizes PD-L2 and prevents its downstream degradation. Disruption of this binding motif compromises PD-L2's cellular stability, underscoring its potential significance in cancer biology. These findings not only deepen our understanding of PD-L2 regulation in the context of tumors, but also open avenues for potential therapeutic interventions.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Taoran Xiao
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maorong Wen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lijuan Shen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lingyu Du
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Shukun Wei
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Wu
- National Facility for Protein Science in Shanghai, ZhangJiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yang Yu
- National Facility for Protein Science in Shanghai, ZhangJiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China
| | - Shuqing Wang
- Tianjin Key Laboratory of Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Qixiangtai Road No.22, Tianjin 300070, China.
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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4
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Issop L, Duma L, Finet S, Lequin O, Lacapère JJ. Among the recombinant TSPOs, the BcTSPO. Biochimie 2024:S0300-9084(24)00029-4. [PMID: 38280504 DOI: 10.1016/j.biochi.2024.01.011] [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: 10/19/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/29/2024]
Abstract
Overexpression of recombinant Bacillus cereus TSPO (BcTSPO) in E. coli bacteria leads to its recovery with a bound hemin both in bacterial membrane (MB) and inclusion bodies (IB). Unlike mouse TSPO, BcTSPO purified in SDS detergent from IB is well structured and can bind various ligands such as high-affinity PK 11195, protoporphyrin IX (PPIX) and δ-aminolevulinic acid (ALA). For each of the three ligands, 1H-15N HSQC titration NMR experiments suggest that different amino acids of BcTSPO binding cavity are involved in the interaction. PPIX, an intermediate of heme biosynthesis, binds to the cavity of BcTSPO and its fluorescence can be significantly reduced in the presence of light and oxygen. The light irradiation leads to two products that have been isolated and characterized as photoporphyrins. They result from the addition of singlet oxygen to the two vinyl groups hence leading to the formation of hydroxyaldehydes. The involvement of water molecules, recently observed along with the binding of heme in Rhodobacter sphaeroides (RsTSPO) is highly probable. Altogether, these results raise the question of the role of TSPO in heme biosynthesis regulation as a possible scavenger of reactive intermediates.
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Affiliation(s)
- Leeyah Issop
- Inserm U955-IMRB, UPEC, Ecole Nationale Vétérinaire d'Alfort, F-94010, Créteil, France
| | - Luminita Duma
- University of Reims Champagne-Ardenne, CNRS, ICMR UMR 7312, 51687, Reims, France
| | - Stephanie Finet
- IMPMC, UMR 7590 CNRS, Sorbonne Université, MNHN, IRD, 75005, Paris, France
| | - Olivier Lequin
- Sorbonne Université, Ecole normale supérieure, PSL University, CNRS (UMR 7203), Laboratoire des Biomolécules, LBM, 75005, Paris, France
| | - Jean-Jacques Lacapère
- Sorbonne Université, Ecole normale supérieure, PSL University, CNRS (UMR 7203), Laboratoire des Biomolécules, LBM, 75005, Paris, France.
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5
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Tournier B, Bouteldja F, Amossé Q, Nicolaides A, Duarte Azevedo M, Tenenbaum L, Garibotto V, Ceyzériat K, Millet P. 18 kDa Translocator Protein TSPO Is a Mediator of Astrocyte Reactivity. ACS OMEGA 2023; 8:31225-31236. [PMID: 37663488 PMCID: PMC10468775 DOI: 10.1021/acsomega.3c03368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023]
Abstract
An increase in astrocyte reactivity has been described in Alzheimer's disease and seems to be related to the presence of a pro-inflammatory environment. Reactive astrocytes show an increase in the density of the 18 kDa translocator protein (TSPO), but TSPO involvement in astrocyte functions remains poorly understood. The goal of this study was to better characterize the mechanisms leading to the increase in TSPO under inflammatory conditions and the associated consequences. For this purpose, the C6 astrocytic cell line was used in the presence of lipopolysaccharide (LPS) or TSPO overexpression mediated by the transfection of a plasmid encoding TSPO. The results show that nonlethal doses of LPS induced TSPO expression at mRNA and protein levels through a STAT3-dependent mechanism and increased the number of mitochondria per cell. LPS stimulated reactive oxygen species (ROS) production and decreased glucose consumption (quantified by the [18F]FDG uptake), and these effects were diminished by FEPPA, a TSPO antagonist. The transfection-mediated overexpression of TSPO induced ROS production, and this effect was blocked by FEPPA. In addition, a synergistic effect of overexpression of TSPO and LPS on ROS production was observed. These data show that the increase of TSPO in astrocytic cells is involved in the regulation of glucose metabolism and in the pro-inflammatory response. These data suggest that the overexpression of TSPO by astrocytes in Alzheimer's disease would have rather deleterious effects by promoting the pro-inflammatory response.
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Affiliation(s)
- Benjamin
B. Tournier
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Farha Bouteldja
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Quentin Amossé
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Alekos Nicolaides
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
| | - Marcelo Duarte Azevedo
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Liliane Tenenbaum
- Laboratory
of Cellular and Molecular Neurotherapies, Center for Neuroscience
Research, Clinical Neuroscience Department, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Valentina Garibotto
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Kelly Ceyzériat
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
- Division
of Nuclear Medicine, Diagnostic Department, University Hospitals of Geneva, Geneva 1206, Switzerland
- CIBM
Center for BioMedical Imaging; NIMTLab, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Philippe Millet
- Department
of Psychiatry, University Hospitals of Geneva, Geneva 1206, Switzerland
- Department
of Psychiatry, University of Geneva, Geneva 1211, Switzerland
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6
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Gutay-Tóth Z, Gellen G, Doan M, Eliason JF, Vincze J, Szente L, Fenyvesi F, Goda K, Vecsernyés M, Szabó G, Bacso Z. Cholesterol-Depletion-Induced Membrane Repair Carries a Raft Conformer of P-Glycoprotein to the Cell Surface, Indicating Enhanced Cholesterol Trafficking in MDR Cells, Which Makes Them Resistant to Cholesterol Modifications. Int J Mol Sci 2023; 24:12335. [PMID: 37569709 PMCID: PMC10419235 DOI: 10.3390/ijms241512335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
The human P-glycoprotein (P-gp), a transporter responsible for multidrug resistance, is present in the plasma membrane's raft and non-raft domains. One specific conformation of P-gp that binds to the monoclonal antibody UIC2 is primarily associated with raft domains and displays heightened internalization in cells overexpressing P-gp, such as in NIH-3T3 MDR1 cells. Our primary objective was to investigate whether the trafficking of this particular P-gp conformer is dependent on cholesterol levels. Surprisingly, depleting cholesterol using cyclodextrin resulted in an unexpected increase in the proportion of raft-associated P-gp within the cell membrane, as determined by UIC2-reactive P-gp. This increase appears to be a compensatory response to cholesterol loss from the plasma membrane, whereby cholesterol-rich raft micro-domains are delivered to the cell surface through an augmented exocytosis process. Furthermore, this exocytotic event is found to be part of a complex trafficking mechanism involving lysosomal exocytosis, which contributes to membrane repair after cholesterol reduction induced by cyclodextrin treatment. Notably, cells overexpressing P-gp demonstrated higher total cellular cholesterol levels, an increased abundance of stable lysosomes, and more effective membrane repair following cholesterol modifications. These modifications encompassed exocytotic events that involved the transport of P-gp-carrying rafts. Importantly, the enhanced membrane repair capability resulted in a durable phenotype for MDR1 expressing cells, as evidenced by significantly improved viabilities of multidrug-resistant Pgp-overexpressing immortal NIH-3T3 MDR1 and MDCK-MDR1 cells compared to their parents when subjected to cholesterol alterations.
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Affiliation(s)
- Zsuzsanna Gutay-Tóth
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Gabriella Gellen
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, 1053 Budapest, Hungary
| | - Minh Doan
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - James F. Eliason
- Great Lakes Stem Cell Innovation Center, Detroit, MI 48202, USA;
| | - János Vincze
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Lajos Szente
- CycloLab Cyclodextrin Research & Development Laboratory, Ltd., 1097 Budapest, Hungary;
| | - Ferenc Fenyvesi
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
| | - Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - Miklós Vecsernyés
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
| | - Zsolt Bacso
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (Z.G.-T.); (G.G.); (M.D.); (K.G.); (G.S.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, 4032 Debrecen, Hungary; (F.F.); (M.V.)
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7
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Luo Z, Yao J, Wang Z, Xu J. Mitochondria in endothelial cells angiogenesis and function: current understanding and future perspectives. J Transl Med 2023; 21:441. [PMID: 37407961 DOI: 10.1186/s12967-023-04286-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
Endothelial cells (ECs) angiogenesis is the process of sprouting new vessels from the existing ones, playing critical roles in physiological and pathological processes such as wound healing, placentation, ischemia/reperfusion, cardiovascular diseases and cancer metastasis. Although mitochondria are not the major sites of energy source in ECs, they function as important biosynthetic and signaling hubs to regulate ECs metabolism and adaptations to local environment, thus affecting ECs migration, proliferation and angiogenic process. The understanding of the importance and potential mechanisms of mitochondria in regulating ECs metabolism, function and the process of angiogenesis has developed in the past decades. Thus, in this review, we discuss the current understanding of mitochondrial proteins and signaling molecules in ECs metabolism, function and angiogeneic signaling, to provide new and therapeutic targets for treatment of diverse cardiovascular and angiogenesis-dependent diseases.
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Affiliation(s)
- Zhen Luo
- Shanghai Key Laboratory of Veterinary Biotechnology/Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Road 800, Minhang District, Shanghai, China
| | - Jianbo Yao
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Zhe Wang
- Shanghai Key Laboratory of Veterinary Biotechnology/Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Road 800, Minhang District, Shanghai, China
| | - Jianxiong Xu
- Shanghai Key Laboratory of Veterinary Biotechnology/Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Road 800, Minhang District, Shanghai, China.
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8
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Cheung G, Lin YC, Papadopoulos V. Translocator protein in the rise and fall of central nervous system neurons. Front Cell Neurosci 2023; 17:1210205. [PMID: 37416505 PMCID: PMC10322222 DOI: 10.3389/fncel.2023.1210205] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Translocator protein (TSPO), a 18 kDa protein found in the outer mitochondrial membrane, has historically been associated with the transport of cholesterol in highly steroidogenic tissues though it is found in all cells throughout the mammalian body. TSPO has also been associated with molecular transport, oxidative stress, apoptosis, and energy metabolism. TSPO levels are typically low in the central nervous system (CNS), but a significant upregulation is observed in activated microglia during neuroinflammation. However, there are also a few specific regions that have been reported to have higher TSPO levels than the rest of the brain under normal conditions. These include the dentate gyrus of the hippocampus, the olfactory bulb, the subventricular zone, the choroid plexus, and the cerebellum. These areas are also all associated with adult neurogenesis, yet there is no explanation of TSPO's function in these cells. Current studies have investigated the role of TSPO in microglia during neuron degeneration, but TSPO's role in the rest of the neuron lifecycle remains to be elucidated. This review aims to discuss the known functions of TSPO and its potential role in the lifecycle of neurons within the CNS.
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9
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Real Hernandez LM, Levental I. Lipid packing is disrupted in copolymeric nanodiscs compared with intact membranes. Biophys J 2023; 122:2256-2266. [PMID: 36641625 PMCID: PMC10257115 DOI: 10.1016/j.bpj.2023.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/02/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Discoidal lipid-protein nanoparticles known as nanodiscs are widely used tools in structural and membrane biology. Amphipathic, synthetic copolymers have recently become an attractive alternative to membrane scaffold proteins for the formation of nanodiscs. Such copolymers can directly intercalate into, and form nanodiscs from, intact membranes without detergents. Although these copolymer nanodiscs can extract native membrane lipids, it remains unclear whether native membrane properties are also retained. To determine the extent to which bilayer lipid packing is retained in nanodiscs, we measured the behavior of packing-sensitive fluorescent dyes in various nanodisc preparations compared with intact lipid bilayers. We analyzed styrene-maleic acid (SMA), diisobutylene-maleic acid (DIBMA), and polymethacrylate (PMA) as nanodisc scaffolds at various copolymer-to-lipid ratios and temperatures. Measurements of Laurdan spectral shifts revealed that dimyristoyl-phosphatidylcholine (DMPC) nanodiscs had increased lipid headgroup packing compared with large unilamellar vesicles (LUVs) above the lipid melting temperature for all three copolymers. Similar effects were observed for DMPC nanodiscs stabilized by membrane scaffolding protein MSP1E1. Increased lipid headgroup packing was also observed when comparing nanodiscs with intact membranes composed of binary mixtures of 1-palmitoyl-2-oleoyl-phosphocholine (POPC) and di-palmitoyl-phosphocholine (DPPC), which show fluid-gel-phase coexistence. Similarly, Laurdan reported increased headgroup packing in nanodiscs for biomimetic mixtures containing cholesterol, most notable for relatively disordered membranes. The magnitudes of these ordering effects were not identical for the various copolymers, with SMA being the most and DIBMA being the least perturbing. Finally, nanodiscs derived from mammalian cell membranes showed similarly increased lipid headgroup packing. We conclude that nanodiscs generally do not completely retain the physical properties of intact membranes.
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Affiliation(s)
- Luis M Real Hernandez
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia
| | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia.
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10
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Di X, Ortega-Alarcon D, Kakumanu R, Iglesias-Fernandez J, Diaz L, Baidoo EEK, Velazquez-Campoy A, Rodríguez-Concepción M, Perez-Gil J. MEP pathway products allosterically promote monomerization of deoxy-D-xylulose-5-phosphate synthase to feedback-regulate their supply. PLANT COMMUNICATIONS 2023; 4:100512. [PMID: 36575800 DOI: 10.1016/j.xplc.2022.100512] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/11/2022] [Accepted: 12/22/2022] [Indexed: 05/11/2023]
Abstract
Isoprenoids are a very large and diverse family of metabolites required by all living organisms. All isoprenoids derive from the double-bond isomers isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are produced by the methylerythritol 4-phosphate (MEP) pathway in bacteria and plant plastids. It has been reported that IPP and DMAPP feedback-regulate the activity of deoxyxylulose 5-phosphate synthase (DXS), a dimeric enzyme that catalyzes the main flux-controlling step of the MEP pathway. Here we provide experimental insights into the underlying mechanism. Isothermal titration calorimetry and dynamic light scattering approaches showed that IPP and DMAPP can allosterically bind to DXS in vitro, causing a size shift. In silico ligand binding site analysis and docking calculations identified a potential allosteric site in the contact region between the two monomers of the active DXS dimer. Modulation of IPP and DMAPP contents in vivo followed by immunoblot analyses confirmed that high IPP/DMAPP levels resulted in monomerization and eventual aggregation of the enzyme in bacterial and plant cells. Loss of the enzymatically active dimeric conformation allows a fast and reversible reduction of DXS activity in response to a sudden increase or decrease in IPP/DMAPP supply, whereas aggregation and subsequent removal of monomers that would otherwise be available for dimerization appears to be a more drastic response in the case of persistent IPP/DMAPP overabundance (e.g., by a blockage in their conversion to downstream isoprenoids). Our results represent an important step toward understanding the regulation of the MEP pathway and rational design of biotechnological endeavors aimed at increasing isoprenoid contents in microbial and plant systems.
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Affiliation(s)
- Xueni Di
- Institute for Plant Molecular and Cell Biology (IBMCP), CSIC-Universitat Politècnica de València, 46022 Valencia, Spain; Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain
| | - David Ortega-Alarcon
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Ramu Kakumanu
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Lucia Diaz
- Nostrum Biodiscovery SL, 08029 Barcelona, Spain
| | - Edward E K Baidoo
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Adrian Velazquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragon), 50009 Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
| | - Manuel Rodríguez-Concepción
- Institute for Plant Molecular and Cell Biology (IBMCP), CSIC-Universitat Politècnica de València, 46022 Valencia, Spain; Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
| | - Jordi Perez-Gil
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
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11
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Liu J, Hiser C, Li F, Hall R, Garavito RM, Ferguson-Miller S. New TSPO Crystal Structures of Mutant and Heme-Bound Forms with Altered Flexibility, Ligand Binding, and Porphyrin Degradation Activity. Biochemistry 2023; 62:1262-1273. [PMID: 36947867 PMCID: PMC10077581 DOI: 10.1021/acs.biochem.2c00612] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 03/09/2023] [Indexed: 03/24/2023]
Abstract
The ancient protein TSPO (translocator protein 18kD) is found in all kingdoms and was originally identified as a binding site of benzodiazepine drugs. Its physiological function remains unclear, although porphyrins are conserved ligands. Several crystal structures of bacterial TSPO and nuclear magnetic resonance structures of a mouse form have revealed monomer and dimer configurations, but there have been no reports of structures with a physiological ligand. Here, we present the first X-ray structures of Rhodobacter sphaeroides TSPO with a physiological ligand bound. Two different variants (substituting threonine for alanine at position 139 (A139T) and phenylalanine for alanine at position 138 (A138F)) yielded well-diffracting crystals giving structures of both apo- and heme-containing forms. Both variants have wild-type micromolar affinity for heme and protoporphyrin IX, but A139T has very low ability to accelerate the breakdown of porphyrin in the presence of light and oxygen. The binding of heme to one protomer of the dimer of either mutant induces a more rigid structure, both in the heme-binding protomer and the protomer without heme bound, demonstrating an allosteric response. Ensemble refinement of the X-ray data reveals distinct regions of altered flexibility in response to single heme binding to the dimer. The A139T variant shows a more rigid structure overall, which may relate to extra hydrogen bonding of waters captured in the heme crevice. As TSPO has been suggested to have a role in heme delivery from mitochondria to the cytoplasm, the new structures provide potential clues regarding the structural basis of such activity.
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Affiliation(s)
- Jian Liu
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Carrie Hiser
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Fei Li
- Amgen
Inc., San Francisco, California 94080, United States
| | - Robert Hall
- Pharmacology
and Chemical Biology, University of Pittsburgh
School of Medicine, Pittsburgh, Pennsylvania 15213, United States
| | - R. Michael Garavito
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Shelagh Ferguson-Miller
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
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12
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Raval NR, Wetherill RR, Wiers CE, Dubroff JG, Hillmer AT. Positron Emission Tomography of Neuroimmune Responses in Humans: Insights and Intricacies. Semin Nucl Med 2023; 53:213-229. [PMID: 36270830 PMCID: PMC11261531 DOI: 10.1053/j.semnuclmed.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 08/30/2022] [Indexed: 11/06/2022]
Abstract
The brain's immune system plays a critical role in responding to immune challenges and maintaining homeostasis. However, dysregulated neuroimmune function contributes to neurodegenerative disease and neuropsychiatric conditions. In vivo positron emission tomography (PET) imaging of the neuroimmune system has facilitated a greater understanding of its physiology and the pathology of some neuropsychiatric conditions. This review presents an in-depth look at PET findings from human neuroimmune function studies, highlighting their importance in current neuropsychiatric research. Although the majority of human PET studies feature radiotracers targeting the translocator protein 18 kDa (TSPO), this review also considers studies with other neuroimmune targets, including monoamine oxidase B, cyclooxygenase-1 and cyclooxygenase-2, nitric oxide synthase, and the purinergic P2X7 receptor. Promising new targets, such as colony-stimulating factor 1, Sphingosine-1-phosphate receptor 1, and the purinergic P2Y12 receptor, are also discussed. The significance of validating neuroimmune targets and understanding their function and expression is emphasized in this review to better identify and interpret PET results.
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Affiliation(s)
- Nakul R Raval
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT
| | - Reagan R Wetherill
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Corinde E Wiers
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ansel T Hillmer
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT; Department of Psychiatry, Yale University, New Haven, CT.
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13
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Combet S, Bonneté F, Finet S, Pozza A, Saade C, Martel A, Koutsioubas A, Lacapère JJ. Effect of amphiphilic environment on the solution structure of mouse TSPO translocator protein. Biochimie 2023; 205:61-72. [PMID: 36460205 DOI: 10.1016/j.biochi.2022.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022]
Abstract
The translocator protein (TSPO) is a ubiquitous transmembrane protein of great pharmacological interest thanks to its high affinity to many drug ligands. The only high-resolution 3D-structure known for mammalian TSPO was obtained by NMR for the mouse mTSPO in DPC detergent only in presence of the high-affinity PK 11195 ligand. An atomic structure of free-ligand mTSPO is still missing to better understand the interaction of ligands with mTSPO and their effects on the protein conformation. Here, we decipher the solution structures of the recombinant mTSPO without ligand both in (i) SDS, the detergent used to extract and purify the protein from E. coli inclusion bodies, and (ii) DPC, the detergent used to solve the PK 11195-binding mTSPO NMR structure. We report partially refolded and less flexible mTSPO helices in DPC compared to SDS. Besides, DPC stabilizes the tertiary structure of mTSPO, as shown by a higher intrinsic Trp fluorescence and changes in indole environment. We evaluate by SEC-MALLS that ∼135 SDS and ∼100 DPC molecules are bound to mTSPO. SEC-small-angle X-ray (SAXS) and neutron (SANS) scattering confirm a larger mTSPO-detergent complex in SDS than in DPC. Using the contrast-matching technique in SEC-SANS, we demonstrate that mTSPO conformation is more compact and less flexible in DPC than in SDS. Combining ab initio modeling with SANS, we confirm that mTSPO conformation is less elongated in DPC than in SDS. However, the free-ligand mTSPO envelope in DPC is not as compact as the PK 11195-binding protein NMR structure, the ligand stiffening the protein.
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Affiliation(s)
- Sophie Combet
- Laboratoire Léon-Brillouin (LLB), UMR12 CEA, CNRS, Université Paris-Saclay, F-91191, Gif-sur-Yvette CEDEX, France.
| | - Françoise Bonneté
- Université Paris Cité, CNRS, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires (IBPC), F-75005, Paris, France.
| | - Stéphanie Finet
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR 7590 CNRS, Sorbonne Université, MNHN, IRD, F-75005, Paris, France
| | - Alexandre Pozza
- Université Paris Cité, CNRS, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires (IBPC), F-75005, Paris, France
| | - Christelle Saade
- Laboratoire Léon-Brillouin (LLB), UMR12 CEA, CNRS, Université Paris-Saclay, F-91191, Gif-sur-Yvette CEDEX, France
| | - Anne Martel
- Institut Laue-Langevin (ILL), F-38042, Grenoble, France
| | - Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, D-85748, Garching, Germany
| | - Jean-Jacques Lacapère
- Laboratoire des BioMolécules (LBM), UMR 7203, Sorbonne Université, Ecole Normale Supérieure, PSL Université, CNRS, 4 place Jussieu, F-75005, Paris, France
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14
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Duma L, Senicourt L, Rigaud B, Papadopoulos V, Lacapère JJ. Solid-state NMR study of structural heterogeneity of the apo WT mouse TSPO reconstituted in liposomes. Biochimie 2023; 205:73-85. [PMID: 36029902 DOI: 10.1016/j.biochi.2022.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/08/2022] [Accepted: 08/18/2022] [Indexed: 11/02/2022]
Abstract
In the last decades, ligand binding to human TSPO has been largely used in clinical neuroimaging, but little is known about the interaction mechanism. Protein conformational mobility plays a key role in the ligand recognition and both, ligand-free and ligand-bound structures, are mandatory for characterizing the molecular binding mechanism. In the absence of crystals for mammalian TSPO, we have exploited solid-state nuclear magnetic resonance (ssNMR) spectroscopy under magic-angle spinning (MAS) to study the apo form of recombinant mouse TSPO (mTSPO) reconstituted in lipids. This environment has been previously described to permit binding of its high-affinity drug ligand PK11195 and appears therefore favourable for the study of molecular dynamics. We have optimized the physical conditions to get the best resolution for MAS ssNMR spectra of the ligand-free mTSPO. We have compared and combined various ssNMR spectra to get dynamical information either for the lipids or for the mTSPO. Partial assignment of residue types suggests few agreements with the published solution NMR assignment of the PK11195-bound mTSPO in DPC detergent. Moreover, we were able to observe some lateral chains of aromatic residues that were not assigned in solution. 13C double-quantum NMR spectroscopy shows remarkable dynamics for ligand-free mTSPO in lipids which may have significant implications on the recognition of the ligand and/or other protein partners.
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Affiliation(s)
- Luminita Duma
- Champagne-Ardenne University, CNRS, ICMR UMR, 7312, Reims, France.
| | - Lucile Senicourt
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 Place Jussieu, F-75005, Paris, France
| | - Baptiste Rigaud
- CNRS Institut des Matériaux de Paris Centre (FR2482), 4 Place Jussieu, 75005, Paris, France
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, 90089, USA
| | - Jean-Jacques Lacapère
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 Place Jussieu, F-75005, Paris, France
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15
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Wang Q, Cao Y, Shen L, Xiao T, Cao R, Wei S, Tang M, Du L, Wu H, Wu B, Yu Y, Wang S, Wen M, OuYang B. Regulation of PD-L1 through direct binding of cholesterol to CRAC motifs. SCIENCE ADVANCES 2022; 8:eabq4722. [PMID: 36026448 PMCID: PMC9417176 DOI: 10.1126/sciadv.abq4722] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/12/2022] [Indexed: 05/24/2023]
Abstract
Cholesterol, an essential molecule for cell structure, function, and viability, plays crucial roles in the development, progression, and survival of cancer cells. Earlier studies have shown that cholesterol-lowering drugs can inhibit the high expression of programmed-death ligand 1 (PD-L1) that contributes to immunoevasion in cancer cells. However, the regulatory mechanism of cell surface PD-L1 abundance by cholesterol is still controversial. Here, using nuclear magnetic resonance and biochemical techniques, we demonstrated that cholesterol can directly bind to the transmembrane domain of PD-L1 through two cholesterol-recognition amino acid consensus (CRAC) motifs, forming a sandwich-like architecture and stabilizing PD-L1 to prevent downstream degradation. Mutations at key binding residues prohibit PD-L1-cholesterol interactions, decreasing the cellular abundance of PD-L1. Our results reveal a unique regulatory mechanism that controls the stability of PD-L1 in cancer cells, providing an alternative method to overcome PD-L1-mediated immunoevasion in cancers.
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunlei Cao
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lijuan Shen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Taoran Xiao
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruiyu Cao
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shukun Wei
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meng Tang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingyu Du
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hongyi Wu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Wu
- National Facility for Protein Science Shanghai, ZhangJiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Yang Yu
- National Facility for Protein Science Shanghai, ZhangJiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Shuqing Wang
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China
| | - Maorong Wen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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16
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Yue YY, Wang YC, Liao ZX, Hu FY, Liu QY, Dong J, Zhong M, Chen MH, Pan YM, Zhong H, Shang J. Peripheral benzodiazepine receptor TSPO needs to be reconsidered before using as a drug target for a pigmentary disorder. FASEB J 2022; 36:e22454. [PMID: 35839067 DOI: 10.1096/fj.202101746rr] [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: 11/17/2021] [Revised: 06/19/2022] [Accepted: 07/06/2022] [Indexed: 11/11/2022]
Abstract
The peripheral benzodiazepine receptor (TSPO/PBR) is highly conserved among different species but with perplexing biochemical functions. Multiple ligands of TSPO show commendable regulatory activities in lots of biological functions, such as neuro-protection, cholesterol transport, and so on. These researches support that TSPO may be a potential target for disease treatment and drug development. Previous studies have shown that its ligands benzodiazepines show a satisfactory effect on melanogenic promotion. However, the potential application of TSPO in drug development for pigmentary disorder needs further investigation. In this study, we confirmed the melanogenesis induction of TSPO ligand, Ro5-4864 in mouse melanoma cell lines, human skin tissue, and zebrafish embryos by inducing melanin synthesis and melanosome transport. Molecular genetics and pharmacological studies showed that TSPO deficiency did not affect melanin production in B16F10 cells and zebrafish embryos, nor did it affect the melanin promotion effect of Ro5-4864. Whether or not TSPO exists, the expression of lots of melanogenesis-related proteins, such as TYR, TRP-1, DCT, Mlph, and Rab27 was upregulated with the Ro5-4864 administration. These results indicated that Ro5-4864 induces melanogenesis in a TSPO-independent manner, which is inconsistent with previous research. This research is a reminder that we need to be very careful during target validation in drug development.
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Affiliation(s)
- Yun-Yun Yue
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yi-Chuan Wang
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Zi-Xian Liao
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Fang-Yuan Hu
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Qiu-Yan Liu
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Dong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Min Zhong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Ming-Han Chen
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yu-Min Pan
- School of Chemistry and Pharmacy, Guangxi Normal University, Guilin, China
| | - Hui Zhong
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jing Shang
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,Jiangsu Key Laboratory of TCM Evaluation and Translational Research, China Pharmaceutical University, Nanjing, China.,NMPA Key Laboratory for Research and Evaluation of Cosmetics, National Institutes for Food and Drug Control, Beijing, China
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17
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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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18
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Guilarte TR, Rodichkin AN, McGlothan JL, Acanda De La Rocha AM, Azzam DJ. Imaging neuroinflammation with TSPO: A new perspective on the cellular sources and subcellular localization. Pharmacol Ther 2021; 234:108048. [PMID: 34848203 DOI: 10.1016/j.pharmthera.2021.108048] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/04/2021] [Accepted: 11/24/2021] [Indexed: 12/14/2022]
Abstract
Translocator Protein 18 kDa (TSPO), previously named Peripheral Benzodiazepine Receptor, is a well-validated and widely used biomarker of neuroinflammation to assess diverse central nervous system (CNS) pathologies in preclinical and clinical studies. Many studies have shown that in animal models of human neurological and neurodegenerative disease and in the human condition, TSPO levels increase in the brain neuropil, and this increase is driven by infiltration of peripheral inflammatory cells and activation of glial cells. Therefore, a clear understanding of the dynamics of the cellular sources of the TSPO response is critically important in the interpretation of Positron Emission Tomography (PET) studies and for understanding the pathophysiology of CNS diseases. Within the normal brain compartment, there are tissues and cells such as the choroid plexus, ependymal cells of the lining of the ventricles, and vascular endothelial cells that also express TSPO at even higher levels than in glial cells. However, there is a paucity of knowledge if these cell types respond and increase TSPO in the diseased brain. These cells do provide a background signal that needs to be accounted for in TSPO-PET imaging studies. More recently, there are reports that TSPO may be expressed in neurons of the adult brain and TSPO expression may be increased by neuronal activity. Therefore, it is essential to study this topic with a great deal of detail, methodological rigor, and rule out alternative interpretations and imaging artifacts. High levels of TSPO are present in the outer mitochondrial membrane. Recent studies have provided evidence of its localization in other cellular compartments including the plasma membrane and perinuclear regions which may define functions that are different from that in mitochondria. A greater understanding of the TSPO subcellular localization in glial cells and infiltrating peripheral immune cells and associated function(s) may provide an additional layer of information to the understanding of TSPO neurobiology. This review is an effort to outline recent advances in understanding the cellular sources and subcellular localization of TSPO in brain cells and to examine remaining questions that require rigorous investigation.
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Affiliation(s)
- Tomás R Guilarte
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America.
| | - Alexander N Rodichkin
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Jennifer L McGlothan
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Arlet Maria Acanda De La Rocha
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
| | - Diana J Azzam
- Brain, Behavior, & the Environment Program, Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, United States of America
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19
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Xiong B, You W, Luo Y, Jin G, Wu M, Xu Y, Yang J, Huang H, Yu C. Investigation of the Possible Allostery of Koumine Extracted From Gelsemium elegans Benth. And Analgesic Mechanism Associated With Neurosteroids. Front Pharmacol 2021; 12:739618. [PMID: 34671258 PMCID: PMC8520994 DOI: 10.3389/fphar.2021.739618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
Translocator protein 18 kDa (TSPO) is an evolutionarily conserved 5-transmembrane domain protein, and has been considered as an important therapeutic target for the treatment of pain. We have recently reported the in vitro and in vivo pharmacological characterization of koumine as a TSPO positive allosteric modulator (PAM), more precisely ago-PAM. However, the probe dependence in the allostery of koumine is an important question to resolve, and the possible analgesic mechanism of koumine remains to be clarified. Here, we report the in vivo evaluation of the allostery of koumine when orthosteric ligand PK11195 was used and preliminarily explore the possible analgesic mechanism of koumine associated with neurosteroids. We find that koumine is an ago-PAM of the PK11195-mediated analgesic effect at TSPO, and the analgesic mechanism of this TSPO ago-PAM may be associated with neurosteroids as the analgesic effects of koumine in the formalin-induced inflammatory pain model and chronic constriction injury-induced neuropathic pain model can be antagonized by neurosteroid synthesis inhibitor aminoglutethimide. Although our results cannot fully clarify the allosteric modulatory effect of koumine, it further prove the allostery in TSPO and provide a solid foundation for koumine to be used as a new clinical candidate drug to treat pain.
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Affiliation(s)
- Bojun Xiong
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Wenbing You
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Yufei Luo
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Guilin Jin
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Minxia Wu
- Public Technology Service Center, Fujian Medical University, Fuzhou, China
| | - Ying Xu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Jian Yang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Huihui Huang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Changxi Yu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
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20
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Kong X, Luo S, Wang YF, Yang GF, Lu GM, Zhang LJ. [ 18F]PBR146 and [ 18F]DPA-714 in vivo Imaging of Neuroinflammation in Chronic Hepatic Encephalopathy Rats. Front Neurosci 2021; 15:678144. [PMID: 34483820 PMCID: PMC8415356 DOI: 10.3389/fnins.2021.678144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/28/2021] [Indexed: 11/22/2022] Open
Abstract
Neuroinflammation is an important pathogenesis of hepatic encephalopathy (HE). The upregulation of translocator protein (TSPO) during neuroinflammation provides an imaging molecular target to evaluate the severity of neuroinflammation in chronic HE rats. [18F]DPA-714 and [18F]PBR146 targeting TSPO are often used for neuroinflammation imaging. This study performed bile duct ligation (BDL) in rats to simulate chronic HE model, tested the behavioral experiments, and conducted [18F]PBR146 and [18F]DPA-714 micro-PET/CT scans followed analyzing the average %ID/g values of the whole brain, brain regions and main organs of subjects. After sacrifice the rats, the blood plasma samples were taken for blood biochemical indexes and plasma inflammatory factor levels examination, the liver and brain specimens were obtained for pathological analysis. The BDL rats showed chronic liver failure with defects in cognition, motor coordination ability and mental state. [18F]PBR146 and [18F]DPA-714 micro-PET/CT imaging results were similar in whole brain of BDL group and Sham group. Besides, some regional brain areas in BDL rats were found abnormal uptakes mainly located in basal ganglia area, auditory cortex, motor cortex, cingulate gyrus, somatosensory cortex, hippocampus, thalamus, midbrain, and medulla oblongata, and these regions also correlated with behavioral alterations. In conclusion, both [18F]PBR146 and [18F]DPA-714 had the similar imaging effects in hepatic encephalopathy models could quantitatively evaluate neuroinflammation load and distribution. The difference brain regions with higher uptake values of radiotracers in BDL rats were correlated with behavioral alterations.
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Affiliation(s)
- Xiang Kong
- Department of Diagnostic Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Song Luo
- Department of Diagnostic Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yun Fei Wang
- Department of Diagnostic Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Gui Fen Yang
- Department of Nuclear Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Guang Ming Lu
- Department of Diagnostic Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Long Jiang Zhang
- Department of Diagnostic Radiology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
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21
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Tournier B, Ceyzériat K, Bouteldja FN, Millet P. Amyloid and Tau Induce Cell Death Independently of TSPO Polymerization and Density Changes. ACS OMEGA 2021; 6:18719-18727. [PMID: 34337211 PMCID: PMC8319921 DOI: 10.1021/acsomega.1c01678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Apoptosis-dependent cell death of astrocytes has been described in Alzheimer's disease and is linked to the presence of two markers of the pathology: the β-amyloid peptide (Aβ) and the hyperphosphorylated Tau protein. Astrocytes also show reactive states characterized by the overexpression of the 18 kDa translocator protein (TSPO). However, TSPO is also known, in other areas of research, to participate in cell proliferation and death. Regulation of its function by autopolymerization has been described, but its involvement in apoptosis remains unknown. The aim was to determine the effects of Aβ, Tau, and TSPO antagonists on proliferation/cell death and TSPO polymerization in the C6 astrocytic cell line. The dose-effect on cell death in response to Aβ and Tau was observed but without alterations of TSPO density and polymerization. In contrast, nanomolar doses of antagonists stimulated cell proliferation, although micromolar doses induced cell death with a reduction in TSPO density and an increase in the ratio between the 36 and the 72 kDa TSPO polymers. Therefore, an alteration in the density and polymerization of TSPO appears to be related to cell death induced by TSPO antagonisms. In contrast, Aβ- and Tau-induced death seems to be independent of TSPO alterations. In conclusion, even if its role in cell death and proliferation is demonstrated, TSPO seems to, in the context of Alzheimer's disease, rather represent a marker of the activity of astrocytes than of cell death.
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Affiliation(s)
- Benjamin
B. Tournier
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
| | - Kelly Ceyzériat
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
- Division
of Nuclear Medicine and Molecular Imaging, Diagnostic Department, University Hospitals of Geneva, 1205 Genève, Switzerland
- Division
of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, 1205 Genève, Switzerland
| | - Farha N. Bouteldja
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
| | - Philippe Millet
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
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22
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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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23
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Xiong B, Jin G, Xu Y, You W, Luo Y, Fang M, Chen B, Huang H, Yang J, Lin X, Yu C. Identification of Koumine as a Translocator Protein 18 kDa Positive Allosteric Modulator for the Treatment of Inflammatory and Neuropathic Pain. Front Pharmacol 2021; 12:692917. [PMID: 34248642 PMCID: PMC8264504 DOI: 10.3389/fphar.2021.692917] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/07/2021] [Indexed: 01/08/2023] Open
Abstract
Koumine is an alkaloid that displays notable activity against inflammatory and neuropathic pain, but its therapeutic target and molecular mechanism still need further study. Translocator protein 18 kDa (TSPO) is a vital therapeutic target for pain treatment, and recent research implies that there may be allostery in TSPO. Our previous competitive binding assay hint that koumine may function as a TSPO positive allosteric modulator (PAM). Here, for the first time, we report the pharmacological characterization of koumine as a TSPO PAM. The results imply that koumine might be a high-affinity ligand of TSPO and that it likely acts as a PAM since it could delay the dissociation of 3H-PK11195 from TSPO. Importantly, the allostery was retained in vivo, as koumine augmented Ro5-4864-mediated analgesic and anti-inflammatory effects in several acute and chronic inflammatory and neuropathic pain models. Moreover, the positive allosteric modulatory effect of koumine on TSPO was further demonstrated in cell proliferation assays in T98G human glioblastoma cells. In summary, we have identified and characterized koumine as a TSPO PAM for the treatment of inflammatory and neuropathic pain. Our data lay a solid foundation for the use of the clinical candidate koumine to treat inflammatory and neuropathic pain, further demonstrate the allostery in TSPO, and provide the first proof of principle that TSPO PAM may be a novel avenue for the discovery of analgesics.
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Affiliation(s)
- Bojun Xiong
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Guilin Jin
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Ying Xu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Wenbing You
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Yufei Luo
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Menghan Fang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Bing Chen
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Huihui Huang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Jian Yang
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Xu Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Changxi Yu
- Department of Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, China.,Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, School of Pharmacy, Fujian Medical University, Fuzhou, China
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24
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Mushtaq AU, Ådén J, Clifton LA, Wacklin-Knecht H, Campana M, Dingeldein APG, Persson C, Sparrman T, Gröbner G. Neutron reflectometry and NMR spectroscopy of full-length Bcl-2 protein reveal its membrane localization and conformation. Commun Biol 2021; 4:507. [PMID: 33907308 PMCID: PMC8079415 DOI: 10.1038/s42003-021-02032-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
B-cell lymphoma 2 (Bcl-2) proteins are the main regulators of mitochondrial apoptosis. Anti-apoptotic Bcl-2 proteins possess a hydrophobic tail-anchor enabling them to translocate to their target membrane and to shift into an active conformation where they inhibit pro-apoptotic Bcl-2 proteins to ensure cell survival. To address the unknown molecular basis of their cell-protecting functionality, we used intact human Bcl-2 protein natively residing at the mitochondrial outer membrane and applied neutron reflectometry and NMR spectroscopy. Here we show that the active full-length protein is entirely buried into its target membrane except for the regulatory flexible loop domain (FLD), which stretches into the aqueous exterior. The membrane location of Bcl-2 and its conformational state seems to be important for its cell-protecting activity, often infamously upregulated in cancers. Most likely, this situation enables the Bcl-2 protein to sequester pro-apoptotic Bcl-2 proteins at the membrane level while sensing cytosolic regulative signals via its FLD region.
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Affiliation(s)
| | - Jörgen Ådén
- Department of Chemistry, University of Umeå, Umeå, Sweden
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science&Innovation Campus, Didcot, Oxfordshire, UK
| | - Hanna Wacklin-Knecht
- European Spallation Source ERIC, ESS, Lund, Sweden
- Department of Chemistry, Division of Physical Chemistry, Lund University, Lund, Sweden
| | - Mario Campana
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science&Innovation Campus, Didcot, Oxfordshire, UK
| | | | - Cecilia Persson
- The Swedish NMR Center, University of Gothenburg, Gothenburg, Sweden
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25
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Fang S, Zhang L, Liu Y, Xu W, Wu W, Huang Z, Wang X, Liu H, Sun Y, Zhang R, Peng B, Liu X, Sun X, Yu J, Chan FKL, Ng SC, Wong SH, Wang MHT, Gin T, Joynt GM, Hui DSC, Feng T, Wu WKK, Chan MTV, Zou X, Xia J. Lysosome activation in peripheral blood mononuclear cells and prognostic significance of circulating LC3B in COVID-19. Brief Bioinform 2021; 22:1466-1475. [PMID: 33620066 PMCID: PMC7929326 DOI: 10.1093/bib/bbab043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/08/2021] [Accepted: 01/28/2021] [Indexed: 01/18/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) has spread rapidly worldwide, causing significant mortality. There is a mechanistic relationship between intracellular coronavirus replication and deregulated autophagosome–lysosome system. We performed transcriptome analysis of peripheral blood mononuclear cells (PBMCs) from COVID-19 patients and identified the aberrant upregulation of genes in the lysosome pathway. We further determined the capability of two circulating markers, namely microtubule-associated proteins 1A/1B light chain 3B (LC3B) and (p62/SQSTM1) p62, both of which depend on lysosome for degradation, in predicting the emergence of moderate-to-severe disease in COVID-19 patients requiring hospitalization for supplemental oxygen therapy. Logistic regression analyses showed that LC3B was associated with moderate-to-severe COVID-19, independent of age, sex and clinical risk score. A decrease in LC3B concentration <5.5 ng/ml increased the risk of oxygen and ventilatory requirement (adjusted odds ratio: 4.6; 95% CI: 1.1–22.0; P = 0.04). Serum concentrations of p62 in the moderate-to-severe group were significantly lower in patients aged 50 or below. In conclusion, lysosome function is deregulated in PBMCs isolated from COVID-19 patients, and the related biomarker LC3B may serve as a novel tool for stratifying patients with moderate-to-severe COVID-19 from those with asymptomatic or mild disease. COVID-19 patients with a decrease in LC3B concentration <5.5 ng/ml will require early hospital admission for supplemental oxygen therapy and other respiratory support.
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Affiliation(s)
- Shisong Fang
- Shenzhen Center for Disease Control and Prevention, China
| | - Lin Zhang
- CUHK-Shenzhen Research Institute, China
| | | | - Wenye Xu
- Chinese University of Hong Kong, Hong Kong
| | - Weihua Wu
- Shenzhen Center for Disease Control and Prevention, China
| | | | - Xin Wang
- Shenzhen Center for Disease Control and Prevention, China
| | - Hui Liu
- Shenzhen Center for Disease Control and Prevention, China
| | - Ying Sun
- Shenzhen Center for Disease Control and Prevention, China
| | - Renli Zhang
- Shenzhen Center for Disease Control and Prevention, China
| | - Bo Peng
- Shenzhen Center for Disease Control and Prevention, China
| | | | - Xiao Sun
- Chinese University of Hong Kong, Hong Kong
| | - Jun Yu
- Chinese University of Hong Kong, Hong Kong
| | | | | | | | | | - Tony Gin
- Chinese University of Hong Kong, Hong Kong
| | | | | | - Tiejian Feng
- Shenzhen Center for Disease Control and Prevention, China
| | | | | | - Xuan Zou
- Shenzhen Center for Disease Control and Prevention, China
| | - Junjie Xia
- Shenzhen Center for Disease Control and Prevention, China
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26
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Georges E, Sottas C, Li Y, Papadopoulos V. Direct and specific binding of cholesterol to the mitochondrial translocator protein (TSPO) using PhotoClick cholesterol analogue. J Biochem 2021; 170:239-243. [PMID: 33846725 DOI: 10.1093/jb/mvab031] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/18/2021] [Indexed: 11/14/2022] Open
Abstract
The translocator protein (TSPO) is a five-helix transmembrane protein localized to the outer mitochondria membrane. Radioligand binding assays and chemical crosslinking showed TSPO to be a high affinity cholesterol-binding protein. In this report, we show that TSPO in mitochondrial fractions from MA-10 mouse tumour Leydig cells can interact directly and competitively with the clickable photoreactive cholesterol analogue. PhotoClick cholesterol showed saturable photoaffinity labelling of TSPO that could be specifically immunoprecipitated with anti-TSPO antibody, following the click reaction with the fluorescent-azide probe, tetramethylrhodamine (TAMRA)-azide. Moreover, excess cholesterol reduced the photolabelling of both total mitochondrial proteins and TSPO. Together, the results of this study demonstrated direct binding of PhotoClick cholesterol to TSPO and that this interaction occurs at physiologically relevant site(s).
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Affiliation(s)
- Elias Georges
- Institute of Parasitology, McGill University, Montreal, Quebec H9X1C0, Canada.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
| | - Chantal Sottas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
| | - Yuchang Li
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
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27
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Rivière G, Jaipuria G, Andreas LB, Leonov A, Giller K, Becker S, Zweckstetter M. Membrane-embedded TSPO: an NMR view. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:173-180. [PMID: 33354729 PMCID: PMC8071791 DOI: 10.1007/s00249-020-01487-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/19/2020] [Accepted: 11/26/2020] [Indexed: 12/21/2022]
Abstract
Translocator Protein (18 kDa) (TSPO) is a mitochondrial transmembrane protein commonly used as a biomarker for neuroinflammation and is also a potential therapeutic target in neurodegenerative diseases. Despite intensive research efforts, the function of TSPO is still largely enigmatic. Deciphering TSPO structure in the native lipid environment is essential to gain insight into its cellular activities and to design improved diagnostic and therapeutic ligands. Here, we discuss the influence of lipid composition on the structure of mammalian TSPO embedded into lipid bilayers on the basis of solid-state NMR experiments. We further highlight that cholesterol can influence both the tertiary and quaternary TSPO structure and also influence TSPO localization in mitochondria-associated endoplasmic reticulum membranes.
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Affiliation(s)
- Gwladys Rivière
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Garima Jaipuria
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Andrei Leonov
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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28
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Najbauer EE, Becker S, Giller K, Zweckstetter M, Lange A, Steinem C, de Groot BL, Griesinger C, Andreas LB. Structure, gating and interactions of the voltage-dependent anion channel. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:159-172. [PMID: 33782728 PMCID: PMC8071794 DOI: 10.1007/s00249-021-01515-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 12/14/2022]
Abstract
The voltage-dependent anion channel (VDAC) is one of the most highly abundant proteins found in the outer mitochondrial membrane, and was one of the earliest discovered. Here we review progress in understanding VDAC function with a focus on its structure, discussing various models proposed for voltage gating as well as potential drug targets to modulate the channel's function. In addition, we explore the sensitivity of VDAC structure to variations in the membrane environment, comparing DMPC-only, DMPC with cholesterol, and near-native lipid compositions, and use magic-angle spinning NMR spectroscopy to locate cholesterol on the outside of the β-barrel. We find that the VDAC protein structure remains unchanged in different membrane compositions, including conditions with cholesterol.
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Affiliation(s)
- Eszter E Najbauer
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Zweckstetter
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
- Senior Research Group of Translational Structural Biology in Dementia, Deutsches Zentrum Für Neurodegenerative Erkrankungen (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut Für Molekulare Pharmakologie, 13125, Berlin, Germany
- Institut Für Biologie, Humboldt-Universität Zu Berlin, 10115, Berlin, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Göttingen, Germany
- Max-Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Bert L de Groot
- Department of Theoretical and Computational Biophysics, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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29
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Elkins MR, Bandara A, Pantelopulos GA, Straub JE, Hong M. Direct Observation of Cholesterol Dimers and Tetramers in Lipid Bilayers. J Phys Chem B 2021; 125:1825-1837. [DOI: 10.1021/acs.jpcb.0c10631] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Matthew R. Elkins
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Asanga Bandara
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - George A. Pantelopulos
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John E. Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
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30
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Leydig cell aging: Molecular mechanisms and treatments. VITAMINS AND HORMONES 2021; 115:585-609. [PMID: 33706963 DOI: 10.1016/bs.vh.2020.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Late-onset hypogonadism, resulting from deficiency in serum testosterone (T), affects the health and quality of life of millions of aging men. T is synthesized by Leydig cells (LCs) in response to luteinizing hormone (LH). LH binds LC plasma membrane receptors, inducing the formation of a supramolecular complex of cytosolic and mitochondrial proteins, the Steroidogenic InteracTomE (SITE). SITE proteins are involved in targeting cholesterol to CYP11A1 in the mitochondria, the first enzyme of the steroidogenic cascade. Cholesterol translocation is the rate-determining step in T formation. With aging, LC defects occur that include changes in SITE, an increasingly oxidative intracellular environment, and reduced androgen formation and serum T levels. T replacement therapy (TRT) will restore T levels, but reported side effects make it desirable to develop additional strategies for increasing T. One approach is to target LC protein-protein interactions and thus increase T production by the hypofunctional Leydig cells themselves.
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Dixon T, Uyar A, Ferguson-Miller S, Dickson A. Membrane-Mediated Ligand Unbinding of the PK-11195 Ligand from TSPO. Biophys J 2021; 120:158-167. [PMID: 33221248 DOI: 10.1101/2020.01.21.914127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/30/2020] [Accepted: 11/10/2020] [Indexed: 05/19/2023] Open
Abstract
The translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is of longstanding medical interest as both a biomarker for neuroinjury and a potential drug target for neuroinflammation and other disorders. Recently, it was shown that ligand residence time is a key factor determining steroidogenic efficacy of TSPO-binding compounds. This spurs interest in simulations of (un)binding pathways of TSPO ligands, which could reveal the molecular interactions governing ligand residence time. In this study, we use a weighted ensemble algorithm to determine the unbinding pathway for different poses of PK-11195, a TSPO ligand used in neuroimaging. In contrast with previous studies, our results show that PK-11195 does not dissociate directly into the solvent but instead dissociates via the lipid membrane by going between the transmembrane helices. We analyze this path ensemble in detail, constructing descriptors that can facilitate a general understanding of membrane-mediated ligand binding. We construct a set of Markov state models augmented with additional straightforward simulations to determine pose-specific ligand residence times. Together, we combine over 40 μs of trajectory data to form a coherent picture of the ligand binding landscape. We find that multiple starting poses yield residence times that roughly agree with the experimental quantity. The ligand binding transition states predicted by these Markov state models occur when PK-11195 is already in the membrane and involves only minimal ligand-protein interactions. This has implications for the design of new long-residence-time TSPO ligands.
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Affiliation(s)
- Tom Dixon
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, Michigan; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Arzu Uyar
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Shelagh Ferguson-Miller
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Alex Dickson
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, Michigan; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan.
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Wiers CE, Martins De Carvalho L, Hodgkinson CA, Schwandt M, Kim SW, Diazgranados N, Wang G, Goldman D, Volkow ND. TSPO polymorphism in individuals with alcohol use disorder: Association with cholesterol levels and withdrawal severity. Addict Biol 2021; 26:e12838. [PMID: 31713961 DOI: 10.1111/adb.12838] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/29/2019] [Accepted: 09/08/2019] [Indexed: 01/19/2023]
Abstract
The translocator protein (TSPO) transports cholesterol into mitochondria and is involved in steroidogenesis. The TSPO polymorphism rs6971 influences binding of cholesterol and other TSPO ligands including positron-emission tomography (PET) imaging radiotracers. Although it is recognized that alcohol increases plasma high-density lipoproteins (HDLs), its effects on total cholesterol and triglycerides along with its relationship to TSPO genotype have not been assessed. Here, we evaluated whether plasma cholesterol and triglycerides are disrupted in alcohol use disorder (AUD) and their association with rs6971 in 932 AUD participants (DSM IV or 5) and 546 controls. AUD participants compared with controls had significantly higher plasma levels of total cholesterol, HDL, and triglycerides, but not of low-density lipoprotein (LDL). In the AUD group only, TSPO rs6971 had a significant effect on plasma levels of cholesterol, LDL, and triglycerides (AA (n = 62) > AG (n = 319) > GG (n = 551)), but not on HDL levels. Additionally, we showed a significant effect of TSPO rs6971 on withdrawal scores (Clinical Institute Withdrawal Assessment for Alcohol [CIWA]), with higher scores in AA (n = 50) compared with AG (n = 238) and GG (n = 428). CIWA scores in AUD participants correlated negatively with LDL and positively with HDL, but not with total cholesterol or triglycerides. These findings corroborate elevated plasma cholesterol and HDL levels in AUD and document significant increases in triglycerides. We also reveal for the first time an association in AUD participants between TSPO rs6971 genotype and plasma cholesterol, LDL, and triglyceride levels (not for HDL) and with withdrawal severity. Mediation analyses revealed that LDL (but not HDL) influenced the association between TSPO and alcohol withdrawal severity.
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Affiliation(s)
- Corinde E. Wiers
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | | | - Colin A. Hodgkinson
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - Melanie Schwandt
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - Sung Won Kim
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - Nancy Diazgranados
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - Gene‐Jack Wang
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - David Goldman
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism National Institutes of Health Bethesda Maryland
- National Institute on Drug Abuse National Institutes of Health Bethesda Maryland
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33
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Aisenbrey C, Rifi O, Bechinger B. Structure, membrane topology and influence of cholesterol of the membrane proximal region: transmembrane helical anchor sequence of gp41 from HIV. Sci Rep 2020; 10:22278. [PMID: 33335248 PMCID: PMC7746737 DOI: 10.1038/s41598-020-79327-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/30/2020] [Indexed: 11/13/2022] Open
Abstract
During the first steps of HIV infection the Env subunit gp41 is thought to establish contact between the membranes and to be the main driver of fusion. Here we investigated in liquid crystalline membranes the structure and cholesterol recognition of constructs made of a gp41 external region carrying a cholesterol recognition amino acid consensus (CRAC) motif and a hydrophobic membrane anchoring sequence. CD- und ATR-FTIR spectroscopies indicate that the constructs adopt a high degree of helical secondary structure in membrane environments. Furthermore, 15N and 2H solid-state NMR spectra of gp41 polypeptides reconstituted into uniaxially oriented bilayers agree with the CRAC domain being an extension of the transmembrane helix. Upon addition of cholesterol the CRAC NMR spectra remain largely unaffected when being associated with the native gp41 transmembrane sequence but its topology changes when anchored in the membrane by a hydrophobic model sequence. The 2H solid-state NMR spectra of deuterated cholesterol are indicative of a stronger influence of the model sequence on this lipid when compared to the native gp41 sequence. These observations are suggestive of a strong coupling between the transmembrane and the membrane proximal region of gp41 possibly enforced by oligomerization of the transmembrane helical region.
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Affiliation(s)
- Christopher Aisenbrey
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Omar Rifi
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Burkhard Bechinger
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France.
- Institut Universitaire de France, Paris, France.
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Ohkawa R, Low H, Mukhamedova N, Fu Y, Lai SJ, Sasaoka M, Hara A, Yamazaki A, Kameda T, Horiuchi Y, Meikle PJ, Pernes G, Lancaster G, Ditiatkovski M, Nestel P, Vaisman B, Sviridov D, Murphy A, Remaley AT, Sviridov D, Tozuka M. Cholesterol transport between red blood cells and lipoproteins contributes to cholesterol metabolism in blood. J Lipid Res 2020; 61:1577-1588. [PMID: 32907987 PMCID: PMC7707172 DOI: 10.1194/jlr.ra120000635] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lipoproteins play a key role in transport of cholesterol to and from tissues. Recent studies have also demonstrated that red blood cells (RBCs), which carry large quantities of free cholesterol in their membrane, play an important role in reverse cholesterol transport. However, the exact role of RBCs in systemic cholesterol metabolism is poorly understood. RBCs were incubated with autologous plasma or isolated lipoproteins resulting in a significant net amount of cholesterol moved from RBCs to HDL, while cholesterol from LDL moved in the opposite direction. Furthermore, the bi-directional cholesterol transport between RBCs and plasma lipoproteins was saturable and temperature-, energy-, and time-dependent, consistent with an active process. We did not find LDLR, ABCG1, or scavenger receptor class B type 1 in RBCs but found a substantial amount of ABCA1 mRNA and protein. However, specific cholesterol efflux from RBCs to isolated apoA-I was negligible, and ABCA1 silencing with siRNA or inhibition with vanadate and Probucol did not inhibit the efflux to apoA-I, HDL, or plasma. Cholesterol efflux from and cholesterol uptake by RBCs from Abca1+/+ and Abca1-/- mice were similar, arguing against the role of ABCA1 in cholesterol flux between RBCs and lipoproteins. Bioinformatics analysis identified ABCA7, ABCG5, lipoprotein lipase, and mitochondrial translocator protein as possible candidates that may mediate the cholesterol flux. Together, these results suggest that RBCs actively participate in cholesterol transport in the blood, but the role of cholesterol transporters in RBCs remains uncertain.
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Affiliation(s)
- Ryunosuke Ohkawa
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Baker Heart and Diabetes Institute, Melbourne, Australia.
| | - Hann Low
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Ying Fu
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Shao-Jui Lai
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mai Sasaoka
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ayuko Hara
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Azusa Yamazaki
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takahiro Kameda
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuna Horiuchi
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Gerard Pernes
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | | | - Paul Nestel
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Boris Vaisman
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Denis Sviridov
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Andrew Murphy
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Alan T Remaley
- Lipoprotein Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
| | - Minoru Tozuka
- Department of Analytical Laboratory Chemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
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35
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Dixon T, Uyar A, Ferguson-Miller S, Dickson A. Membrane-Mediated Ligand Unbinding of the PK-11195 Ligand from TSPO. Biophys J 2020; 120:158-167. [PMID: 33221248 DOI: 10.1016/j.bpj.2020.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/30/2020] [Accepted: 11/10/2020] [Indexed: 12/19/2022] Open
Abstract
The translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is of longstanding medical interest as both a biomarker for neuroinjury and a potential drug target for neuroinflammation and other disorders. Recently, it was shown that ligand residence time is a key factor determining steroidogenic efficacy of TSPO-binding compounds. This spurs interest in simulations of (un)binding pathways of TSPO ligands, which could reveal the molecular interactions governing ligand residence time. In this study, we use a weighted ensemble algorithm to determine the unbinding pathway for different poses of PK-11195, a TSPO ligand used in neuroimaging. In contrast with previous studies, our results show that PK-11195 does not dissociate directly into the solvent but instead dissociates via the lipid membrane by going between the transmembrane helices. We analyze this path ensemble in detail, constructing descriptors that can facilitate a general understanding of membrane-mediated ligand binding. We construct a set of Markov state models augmented with additional straightforward simulations to determine pose-specific ligand residence times. Together, we combine over 40 μs of trajectory data to form a coherent picture of the ligand binding landscape. We find that multiple starting poses yield residence times that roughly agree with the experimental quantity. The ligand binding transition states predicted by these Markov state models occur when PK-11195 is already in the membrane and involves only minimal ligand-protein interactions. This has implications for the design of new long-residence-time TSPO ligands.
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Affiliation(s)
- Tom Dixon
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, Michigan; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Arzu Uyar
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Shelagh Ferguson-Miller
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Alex Dickson
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, Michigan; Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan.
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36
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Si Chaib Z, Marchetto A, Dishnica K, Carloni P, Giorgetti A, Rossetti G. Impact of Cholesterol on the Stability of Monomeric and Dimeric Forms of the Translocator Protein TSPO: A Molecular Simulation Study. Molecules 2020; 25:molecules25184299. [PMID: 32961709 PMCID: PMC7570527 DOI: 10.3390/molecules25184299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 11/25/2022] Open
Abstract
The translocator protein (TSPO) is a transmembrane protein present across the three domains of life. Its functional quaternary structure consists of one or more subunits. In mice, the dimer-to-monomer equilibrium is shifted in vitro towards the monomer by adding cholesterol, a natural component of mammalian membranes. Here, we present a coarse-grained molecular dynamics study on the mouse protein in the presence of a physiological content and of an excess of cholesterol. The latter turns out to weaken the interfaces of the dimer by clusterizing mostly at the inter-monomeric space and pushing the contact residues apart. It also increases the compactness and the rigidity of the monomer. These two factors might play a role for the experimentally observed incremented stability of the monomeric form with increased content of cholesterol. Comparison with simulations on bacterial proteins suggests that the effect of cholesterol is much less pronounced for the latter than for the mouse protein.
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Affiliation(s)
- Zeineb Si Chaib
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52062 Aachen, Germany
| | - Alessandro Marchetto
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Klevia Dishnica
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Paolo Carloni
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen, 52062 Aachen, Germany
- Institute for Neuroscience and Medicine (INM-11) “Molecular Neuroscience and Neuroimaging”, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Alejandro Giorgetti
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
- Correspondence: (A.G.); (G.R.)
| | - Giulia Rossetti
- Institute for Neuroscience and Medicine (INM-9) and Institute for Advanced Simulations (IAS-5) “Computational biomedicine”, Forschungszentrum Jülich, 52425 Jülich, Germany; (Z.S.C.); (A.M.); (P.C.)
- Jülich Supercomputing Center (JSC), Forschungszentrum Jülich, 52425 Jülich, Germany
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation University Hospital Aachen, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Correspondence: (A.G.); (G.R.)
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37
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In Vivo TSPO Signal and Neuroinflammation in Alzheimer's Disease. Cells 2020; 9:cells9091941. [PMID: 32839410 PMCID: PMC7565089 DOI: 10.3390/cells9091941] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/15/2022] Open
Abstract
In the last decade, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in in vivo imaging has attempted to demonstrate the presence of neuroinflammatory reactions by measuring the 18 kDa translocator protein (TSPO) expression in many diseases of the central nervous system. We focus on two pathological conditions for which neuropathological studies have shown the presence of neuroinflammation, which translates in opposite in vivo expression of TSPO. Alzheimer's disease has been the most widely assessed with more than forty preclinical and clinical studies, showing overall that TSPO is upregulated in this condition, despite differences in the topography of this increase, its time-course and the associated cell types. In the case of schizophrenia, a reduction of TSPO has instead been observed, though the evidence remains scarce and contradictory. This review focuses on the key characteristics of TSPO as a biomarker of neuroinflammation in vivo, namely, on the cellular origin of the variations in its expression, on its possible biological/pathological role and on its variations across disease phases.
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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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39
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Qiu ZK, Liu X, Chen Y, Wu RJ, Guan SF, Pan YY, Wang QB, Tang D, Zhu T, Chen JS. Translocator protein 18 kDa: a potential therapeutic biomarker for post traumatic stress disorder. Metab Brain Dis 2020; 35:695-707. [PMID: 32172519 DOI: 10.1007/s11011-020-00548-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 02/10/2020] [Indexed: 11/11/2022]
Abstract
Post traumatic stress disorder (PTSD) is widely regarded as a stress-related and trauma disorder. The symptoms of PTSD are characterized as a spectrum of vulnerabilities after the exposure to an extremely traumatic stressor. Considering as one of complex mental disorders, little progress has been made toward its diagnostic biomarkers, despite the involvement of PTSD has been studied. Many studies into the underlying neurobiology of PTSD implicated the dysfunction of neurosteroids biosynthesis and neuorinflammatory processes. Translocator protein 18 kDa (TSPO) has been considered as one of the promising therapeutic biomarkers for neurological stress disorders (like PTSD, depression, anxiety, et al) without the benzodiazepine-like side effects. This protein participates in the formation of neurosteroids and modulation of neuroinflammation. The review outlines current knowledge involving the role of TSPO in the neuropathology of PTSD and the anti-PTSD-like effects of TSPO ligands.
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Affiliation(s)
- Zhi-Kun Qiu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Xu Liu
- Pharmacy Department of Medical Supplies Center of General Hospital of Chinese People's Armed Police Forces, Beijing, 100039, People's Republic of China
| | - Yong Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Rong-Jia Wu
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Shi-Feng Guan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Yun-Yun Pan
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Qian-Bo Wang
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China
| | - Dan Tang
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Tao Zhu
- Guangdong Provincial Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Ji-Sheng Chen
- Pharmaceutical Department of The First Affiliated Hospital of Guangdong Pharmaceutical University, Clinical Pharmacy Department of Guangdong Pharmaceutical University, Guangzhou, 510080, People's Republic of China.
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40
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Allostery in membrane proteins. Curr Opin Struct Biol 2020; 62:197-204. [DOI: 10.1016/j.sbi.2020.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/09/2020] [Accepted: 03/09/2020] [Indexed: 12/21/2022]
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41
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Tonon MC, Vaudry H, Chuquet J, Guillebaud F, Fan J, Masmoudi-Kouki O, Vaudry D, Lanfray D, Morin F, Prevot V, Papadopoulos V, Troadec JD, Leprince J. Endozepines and their receptors: Structure, functions and pathophysiological significance. Pharmacol Ther 2020; 208:107386. [DOI: 10.1016/j.pharmthera.2019.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
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42
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Betlazar C, Middleton RJ, Banati R, Liu GJ. The Translocator Protein (TSPO) in Mitochondrial Bioenergetics and Immune Processes. Cells 2020; 9:cells9020512. [PMID: 32102369 PMCID: PMC7072813 DOI: 10.3390/cells9020512] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 12/11/2022] Open
Abstract
The translocator protein (TSPO) is an outer mitochondrial membrane protein that is widely used as a biomarker of neuroinflammation, being markedly upregulated in activated microglia in a range of brain pathologies. Despite its extensive use as a target in molecular imaging studies, the exact cellular functions of this protein remain in question. The long-held view that TSPO plays a fundamental role in the translocation of cholesterol through the mitochondrial membranes, and thus, steroidogenesis, has been disputed by several groups with the advent of TSPO knockout mouse models. Instead, much evidence is emerging that TSPO plays a fundamental role in cellular bioenergetics and associated mitochondrial functions, also part of a greater role in the innate immune processes of microglia. In this review, we examine the more direct experimental literature surrounding the immunomodulatory effects of TSPO. We also review studies which highlight a more central role for TSPO in mitochondrial processes, from energy metabolism, to the propagation of inflammatory responses through reactive oxygen species (ROS) modulation. In this way, we highlight a paradigm shift in approaches to TSPO functioning.
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Affiliation(s)
- Calina Betlazar
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
- Correspondence: (C.B.); (G-J.L.)
| | - Ryan J. Middleton
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
| | - Richard Banati
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
| | - Guo-Jun Liu
- Human Health, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; (R.J.M.); (R.B.)
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia
- Correspondence: (C.B.); (G-J.L.)
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43
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Lacapere JJ, Duma L, Finet S, Kassiou M, Papadopoulos V. Insight into the Structural Features of TSPO: Implications for Drug Development. Trends Pharmacol Sci 2020; 41:110-122. [PMID: 31864680 PMCID: PMC7021566 DOI: 10.1016/j.tips.2019.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 11/13/2019] [Accepted: 11/18/2019] [Indexed: 01/01/2023]
Abstract
The translocator protein (TSPO), an 18-kDa transmembrane protein primarily found in the outer mitochondrial membrane, is evolutionarily conserved and widely distributed across species. In mammals, TSPO has been described as a key member of a multiprotein complex involved in many putative functions and, over the years, several classes of ligand have been developed to modulate these functions. In this review, we consider the currently available atomic structures of mouse and bacterial TSPO and propose a rationale for the development of new ligands for the protein. We provide a review of TSPO monomeric and oligomeric states and their conformational flexibility, together with ligand-binding site and interaction mechanisms. These data are expected to help considerably the development of high-affinity ligands for TSPO-based therapies or diagnostics.
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Affiliation(s)
- Jean-Jacques Lacapere
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 Place Jussieu, F-75005 Paris, France.
| | - Luminita Duma
- CNRS Enzyme and Cell Engineering Laboratory, Sorbonne Université, Université de Technologie de Compiègne, 60203 Compiègne Cedex, France
| | - Stephanie Finet
- IMPMC, UMR 7590 CNRS Sorbonne Université, 4 Place Jussieu, F-75005 Paris, France
| | - Michael Kassiou
- School of Chemistry, Faculty of Science, The University of Sydney, F11, Eastern Ave, Sydney, NSW 2006, Australia
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA
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44
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Desai R, Campanella M. Exploring mitochondrial cholesterol signalling for therapeutic intervention in neurological conditions. Br J Pharmacol 2019; 176:4284-4292. [PMID: 31077345 PMCID: PMC6887905 DOI: 10.1111/bph.14697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 02/25/2019] [Accepted: 03/10/2019] [Indexed: 02/06/2023] Open
Abstract
The pharmacological targeting of cholesterol levels continues to generate interest due to the undoubted success of therapeutic agents, such as statins, in extending life expectancy by modifying the prognosis of diseases associated with the impairment of lipid metabolism. Advances in our understanding of mitochondrial dysfunction in chronic age-related diseases of the brain have disclosed an emerging role for mitochondrial cholesterol in their pathophysiology, thus delineating an opportunity to provide mechanistic insights and explore strategies of intervention. This review draws attention to novel signalling mechanisms in conditions linked with impaired metabolism associated with impaired handling of cholesterol and its oxidized forms (oxysterols) by mitochondria. By emphasizing the role of mitochondrial cholesterol in neurological diseases, we here call for novel approaches and new means of assessment. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.
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Affiliation(s)
- Radha Desai
- Department of Comparative Biomedical SciencesThe Royal Veterinary College, University of LondonLondonUK
| | - Michelangelo Campanella
- Department of Comparative Biomedical SciencesThe Royal Veterinary College, University of LondonLondonUK
- Consortium for Mitochondrial Research (CfMR)University College LondonLondonUK
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45
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Salnikov ES, Aisenbrey C, Pokrandt B, Brügger B, Bechinger B. Structure, Topology, and Dynamics of Membrane-Inserted Polypeptides and Lipids by Solid-State NMR Spectroscopy: Investigations of the Transmembrane Domains of the DQ Beta-1 Subunit of the MHC II Receptor and of the COP I Protein p24. Front Mol Biosci 2019; 6:83. [PMID: 31608287 PMCID: PMC6769064 DOI: 10.3389/fmolb.2019.00083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/23/2019] [Indexed: 01/04/2023] Open
Abstract
MHC class II receptors carry important function in adaptive immunity and their malfunctioning is associated with diabetes type I, chronic inflammatory diseases and other autoimmune diseases. The protein assembles from the DQ alpha-1 and DQ beta-1 subunits where the transmembrane domains of these type I membrane proteins have been shown to be involved in homo- and heterodimer formation. Furthermore, the DQ alpha 1 chain carries a sequence motif that has been first identified in the context of p24, a protein involved in the formation of COPI vesicles of the intracellular transport machinery, to specifically interact with sphingomyelin-C18 (SM-C18). Here we investigated the membrane interactions and dynamics of DQ beta-1 in liquid crystalline POPC phospholipid bilayers by oriented 15N solid-state NMR spectroscopy. The 15N resonances are indicative of a helical tilt angle of the membrane anchor sequence around 20°. Two populations can be distinguished by their differential dynamics probably corresponding the DQ beta-1 mono- and homodimer. Whereas, this equilibrium is hardly affected by the addition of 5 mole% SM-C18 a single population is visible in DMPC lipid bilayers suggesting that the lipid saturation is an important parameter. Furthermore, the DQ alpha-1, DQ beta-1 and p24 transmembrane helical domains were reconstituted into POPC or POPC/SM-C18 lipid bilayers where the fatty acyl chain of either the phosphatidylcholine or of the sphingolipid have been deuterated. Interestingly in the presence of both sphingolipid and polypeptide a strong decrease in the innermost membrane order of the POPC palmitoyl chain is observed, an effect that is strongest for DQ beta-1. In contrast, for the first time the polypeptide interactions were monitored by deuteration of the stearoyl chain of SM-C18. The resulting 2H solid-state NMR spectra show an increase in order for p24 and DQ alpha-1 which both carry the SM recognition motif. Thereby the data are suggestive that SM-C18 together with the transmembrane domains form structures imposing positive curvature strain on the surrounding POPC lipids. This effect is attenuated when SM-C18 is recognized by the protein.
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Affiliation(s)
- Evgeniy S Salnikov
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
| | | | - Bianca Pokrandt
- Biochemiezentrum der Universität Heidelberg, Heidelberg, Germany
| | - Britta Brügger
- Biochemiezentrum der Universität Heidelberg, Heidelberg, Germany
| | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
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46
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Bruno A, Barresi E, Simola N, Da Pozzo E, Costa B, Novellino E, Da Settimo F, Martini C, Taliani S, Cosconati S. Unbinding of Translocator Protein 18 kDa (TSPO) Ligands: From in Vitro Residence Time to in Vivo Efficacy via in Silico Simulations. ACS Chem Neurosci 2019; 10:3805-3814. [PMID: 31268683 DOI: 10.1021/acschemneuro.9b00300] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Translocator protein 18 kDa (TSPO) is a validated pharmacological target for the development of new treatments for neurological disorders. N,N-Dialkyl-2-phenylindol-3-ylglyoxylamides (PIGAs) are effective TSPO modulators and potentially useful therapeutics for the treatment of anxiety, central nervous system pathologies featuring astrocyte loss, and inflammatory-based neuropathologies. For this class of compounds, no correlation exists between the TSPO binding affinity and the corresponding functional efficacy. Rather, their biological effectiveness correlates with the kinetics of the unbinding events and more specifically with the residence time (RT). So far, the structural reasons for the different recorded RT of congeneric PIGAs remain elusive. Here, to understand the different kinetics of PIGAs, their unbinding paths were studied by employing enhanced-sampling molecular dynamics simulations. Results of these studies revealed how subtle structural differences between PIGAs have a substantial effect on the unbinding energetics. In particular, during the egress from the TSPO binding site, slow-dissociating PIGAs find tight interactions with the protein LP1 region thereby determining a long RT. Further support to these findings was achieved by in vivo studies, which demonstrated how the anxiolytic effect observed for the inspected PIGAs correlated with their RT to TSPO.
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Affiliation(s)
- Agostino Bruno
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131 Naples, Italy
| | - Elisabetta Barresi
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Nicola Simola
- Department of Biomedical Sciences, University of Cagliari, Monserrato University Campus, 09042 Monserrato, Italy
| | - Eleonora Da Pozzo
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Barbara Costa
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Ettore Novellino
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131 Naples, Italy
| | - Federico Da Settimo
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Sabrina Taliani
- Department of Pharmacy, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Sandro Cosconati
- DiSTABiF, University of Campania “Luigi Vanvitelli”, Via Vivaldi 43, 81100 Caserta, Italy
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47
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Elkins MR, Hong M. Elucidating ligand-bound structures of membrane proteins using solid-state NMR spectroscopy. Curr Opin Struct Biol 2019; 57:103-109. [PMID: 30903830 PMCID: PMC6697555 DOI: 10.1016/j.sbi.2019.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 01/08/2023]
Abstract
Magic-angle-spinning (MAS) solid-state NMR spectroscopy is a versatile technique to elucidate functionally important protein-ligand interactions in lipid membranes. Here, we review recent solid-state NMR studies of membrane protein interactions with cholesterol, lipids, transported substrates, and peptide ligands. These studies are conducted in synthetic or native lipid bilayers to provide an accurate environment for ligand binding. The solid-state NMR approaches include multinuclear detection to gain comprehensive structural information, distance measurements to locate ligand-binding sites, and dynamic nuclear polarization and 1H detection to enhance spectral sensitivity. These studies provide novel insights into the mechanisms of virus budding, virus entry into cells, transmembrane signaling, substrate transport, antibacterial action, and many other biological processes.
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Affiliation(s)
- Matthew R Elkins
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States.
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48
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Xia Y, Ledwitch K, Kuenze G, Duran A, Li J, Sanders CR, Manning C, Meiler J. A unified structural model of the mammalian translocator protein (TSPO). JOURNAL OF BIOMOLECULAR NMR 2019; 73:347-364. [PMID: 31243635 PMCID: PMC8006375 DOI: 10.1007/s10858-019-00257-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 06/10/2019] [Indexed: 05/10/2023]
Abstract
The translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor (PBR), is a membrane protein located on the outer mitochondrial membrane. Experimentally-derived structures of mouse TSPO (mTSPO) and its homologs from bacterial species have been determined by NMR spectroscopy and X-ray crystallography, respectively. These structures and ligand interactions within the TSPO binding pocket display distinct differences. Here, we leverage experimental and computational studies to derive a unified structural model of mTSPO in the presence and absence of the TSPO ligand, PK11195, and study the effects of DPC detergent micelles on the TSPO structure and ligand binding. From this work, we conclude that that the lipid-mimetic system used to solubilize mTSPO for NMR studies thermodynamically destabilizes the protein, introduces structural perturbations, and alters the characteristics of ligand binding. Furthermore, we used Rosetta to construct a unified mTSPO model that reconciles deviating features of the mammalian and bacterial TSPO. These deviating features are likely a consequence of the detergent system used for structure determination of mTSPO by NMR. The unified mTSPO model agrees with available experimental NMR data, appears to be physically realistic (i.e. thermodynamically not frustrated as judged by the Rosetta energy function), and simultaneously shares the structural features observed in sequence-conserved regions of the bacterial proteins. Finally, we identified the binding site for an imaging ligand VUIIS8310 that is currently positioned for clinical translation using NMR spectroscopy and propose a computational model of the VUIIS8310-mTSPO complex.
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Affiliation(s)
- Yan Xia
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Kaitlyn Ledwitch
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Georg Kuenze
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Amanda Duran
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jun Li
- Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37240, USA
| | - Charles Manning
- Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA.
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, MRBIII 5144B, Nashville, TN, 37232, USA.
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49
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Investigating targets for neuropharmacological intervention by molecular dynamics simulations. Biochem Soc Trans 2019; 47:909-918. [PMID: 31085614 DOI: 10.1042/bst20190048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/23/2019] [Indexed: 01/09/2023]
Abstract
Medical research has identified over 500 brain disorders. Among these, there are still only very few neuropathologies whose causes are fully understood and, consequently, very few drugs whose mechanism of action is known. No FDA drug has been identified for major neurodegenerative diseases, such as Alzheimer's and Parkinson's. We still lack effective treatments and strategies for modulating progression or even early neurodegenerative disease onset diagnostic tools. A great support toward the highly needed identification of neuroactive drugs comes from computer simulation methods and, in particular, from molecular dynamics (MD). This provides insight into structure-function relationship of a target and predicts structure, dynamics and energetics of ligand/target complexes under biologically relevant conditions like temperature and physiological saline concentration. Here, we present examples of the predictive power of MD for neuroactive ligands/target complexes. This brief survey from our own research shows the usefulness of partnerships between academia and industry, and from joint efforts between experimental and theoretical groups.
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50
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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