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Shawer H, Norman K, Cheng CW, Foster R, Beech DJ, Bailey MA. ORAI1 Ca 2+ Channel as a Therapeutic Target in Pathological Vascular Remodelling. Front Cell Dev Biol 2021; 9:653812. [PMID: 33937254 PMCID: PMC8083964 DOI: 10.3389/fcell.2021.653812] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022] Open
Abstract
In the adult, vascular smooth muscle cells (VSMC) are normally physiologically quiescent, arranged circumferentially in one or more layers within blood vessel walls. Remodelling of native VSMC to a proliferative state for vascular development, adaptation or repair is driven by platelet-derived growth factor (PDGF). A key effector downstream of PDGF receptors is store-operated calcium entry (SOCE) mediated through the plasma membrane calcium ion channel, ORAI1, which is activated by the endoplasmic reticulum (ER) calcium store sensor, stromal interaction molecule-1 (STIM1). This SOCE was shown to play fundamental roles in the pathological remodelling of VSMC. Exciting transgenic lineage-tracing studies have revealed that the contribution of the phenotypically-modulated VSMC in atherosclerotic plaque formation is more significant than previously appreciated, and growing evidence supports the relevance of ORAI1 signalling in this pathologic remodelling. ORAI1 has also emerged as an attractive potential therapeutic target as it is accessible to extracellular compound inhibition. This is further supported by the progression of several ORAI1 inhibitors into clinical trials. Here we discuss the current knowledge of ORAI1-mediated signalling in pathologic vascular remodelling, particularly in the settings of atherosclerotic cardiovascular diseases (CVDs) and neointimal hyperplasia, and the recent developments in our understanding of the mechanisms by which ORAI1 coordinates VSMC phenotypic remodelling, through the activation of key transcription factor, nuclear factor of activated T-cell (NFAT). In addition, we discuss advances in therapeutic strategies aimed at the ORAI1 target.
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Affiliation(s)
- Heba Shawer
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Katherine Norman
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.,School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Chew W Cheng
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Richard Foster
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.,School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - David J Beech
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Marc A Bailey
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
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Supra-Molecular Assemblies of ORAI1 at Rest Precede Local Accumulation into Puncta after Activation. Int J Mol Sci 2021; 22:ijms22020799. [PMID: 33466866 PMCID: PMC7831003 DOI: 10.3390/ijms22020799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
The Ca2+ selective channel ORAI1 and endoplasmic reticulum (ER)-resident STIM proteins form the core of the channel complex mediating store operated Ca2+ entry (SOCE). Using liquid phase electron microscopy (LPEM), the distribution of ORAI1 proteins was examined at rest and after SOCE-activation at nanoscale resolution. The analysis of over seven hundred thousand ORAI1 positions revealed a number of ORAI1 channels had formed STIM-independent distinct supra-molecular clusters. Upon SOCE activation and in the presence of STIM proteins, a fraction of ORAI1 assembled in micron-sized two-dimensional structures, such as the known puncta at the ER plasma membrane contact zones, but also in divergent structures such as strands, and ring-like shapes. Our results thus question the hypothesis that stochastically migrating single ORAI1 channels are trapped at regions containing activated STIM, and we propose instead that supra-molecular ORAI1 clusters fulfill an amplifying function for creating dense ORAI1 accumulations upon SOCE-activation.
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da Rocha Nina Junior A, Furtunato Maia JM, Vitor Martins SC, Gonçalves JFDC. Photochemical Efficiency and Oxidative Metabolism of Tree Species during Acclimation to High and Low Irradiance. PLANTS 2020; 9:plants9081047. [PMID: 32824598 PMCID: PMC7463730 DOI: 10.3390/plants9081047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 01/31/2023]
Abstract
The balance between efficiency of absorption and use of light energy is fundamental for plant metabolism and to avoid photoinhibition. Here, we investigated the effects of light environments on the photosynthetic apparatus of tropical tree species of three successional groups (pioneer, mid-, and late successional) subjected to different light conditions: full sunlight (FS), moderate shade (MS), and deep shade (DS). Twenty-nine ecophysiological parameters were correlated with each other. The pioneer species exhibited better photochemical performance and a more efficient antioxidant enzymatic system in comparison with the other successional groups. Plants in FS showed higher intensity of lipid peroxidation, with superoxide dismutase having a prominent role in the antioxidant system. At lower irradiance the enzymatic activity was reduced, and the photochemical efficiency was the preferred way to reduce oxidative damages. P was highly related to photochemical yield, and the N modulation amplified the light harvesting complex in DS to the detriment of the antioxidant system. Despite evidence of cell damage, most species exhibited the ability to adjust to high irradiance. Contrary to expectations, Hymenea courbaril (late-successional) exhibited higher plasticity to fluorescence, nutritional, and antioxidant parameters. Only Carapa guianensis (late-successional) displayed photoinhibitory damage in FS, and Ochroma pyramidale (pioneer) did not survive in DS, suggesting that acclimation to shade is more challenging than to high irradiance.
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Affiliation(s)
- Adamir da Rocha Nina Junior
- Federal Institute of Education, Science and Technology of Amazonas (IFAM)–Campus Humaitá, BR230 Highway, KM 07, Humaitá-AM 69.800-000, Brazil;
| | - Jair Max Furtunato Maia
- University of State of Amazonas (UEA), Av. Djalma Batista, 2470, Manaus-AM 69.050-010, Brazil;
| | | | - José Francisco de Carvalho Gonçalves
- National Institute for Amazonian Research (INPA), Laboratory of Plant Physiology and Biochemistry, Av. André Araújo, 2936, Aleixo, Manaus-AM 69.011-970, Brazil
- Correspondence:
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Alansary D, Peckys DB, Niemeyer BA, de Jonge N. Detecting single ORAI1 proteins within the plasma membrane reveals higher-order channel complexes. J Cell Sci 2020; 133:jcs.240358. [PMID: 31822631 DOI: 10.1242/jcs.240358] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/02/2019] [Indexed: 12/22/2022] Open
Abstract
ORAI1 proteins form highly selective Ca2+ channels in the plasma membrane. Crystallographic data point towards a hexameric stoichiometry of ORAI1 channels, whereas optical methods postulated ORAI1 channels to reside as dimers at rest, and other data suggests that they have a tetrameric configuration. Here, liquid-phase scanning transmission electron microscopy (STEM) and quantum dot (QD) labeling was utilized to study the conformation of ORAI1 proteins at rest. To address the question of whether ORAI1 was present as a dimer, experiments were designed using single ORAI1 monomers and covalently linked ORAI1 dimers with either one or two label-binding positions. The microscopic data was statistically analyzed via the pair correlation function. Label pairs were found in all cases, even for concatenated dimers with one label-binding position, which is only possible if a significant fraction of ORAI1 was assembled in larger order oligomers than dimers, binding at least two QDs. This interpretation of the data was consistent with Blue Native PAGE analysis showing that ORAI1 is mainly present as a complex of an apparent molecular mass larger than that calculated for a dimer.
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Affiliation(s)
- Dalia Alansary
- Molecular Biophysics, University of Saarland, Center for Integrative Physiology and Molecular Medicine, 66421 Homburg/Saar, Germany
| | - Diana B Peckys
- Molecular Biophysics, University of Saarland, Center for Integrative Physiology and Molecular Medicine, 66421 Homburg/Saar, Germany
| | - Barbara A Niemeyer
- Molecular Biophysics, University of Saarland, Center for Integrative Physiology and Molecular Medicine, 66421 Homburg/Saar, Germany
| | - Niels de Jonge
- INM - Leibniz Institute for New Materials, 66123 Saarbrücken, Germany .,Department of Physics, University of Saarland, 66123 Saarbrücken, Germany
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Pu S, Gong C, Robertson AW. Liquid cell transmission electron microscopy and its applications. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191204. [PMID: 32218950 PMCID: PMC7029903 DOI: 10.1098/rsos.191204] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Transmission electron microscopy (TEM) has long been an essential tool for understanding the structure of materials. Over the past couple of decades, this venerable technique has undergone a number of revolutions, such as the development of aberration correction for atomic level imaging, the realization of cryogenic TEM for imaging biological specimens, and new instrumentation permitting the observation of dynamic systems in situ. Research in the latter has rapidly accelerated in recent years, based on a silicon-chip architecture that permits a versatile array of experiments to be performed under the high vacuum of the TEM. Of particular interest is using these silicon chips to enclose fluids safely inside the TEM, allowing us to observe liquid dynamics at the nanoscale. In situ imaging of liquid phase reactions under TEM can greatly enhance our understanding of fundamental processes in fields from electrochemistry to cell biology. Here, we review how in situ TEM experiments of liquids can be performed, with a particular focus on microchip-encapsulated liquid cell TEM. We will cover the basics of the technique, and its strengths and weaknesses with respect to related in situ TEM methods for characterizing liquid systems. We will show how this technique has provided unique insights into nanomaterial synthesis and manipulation, battery science and biological cells. A discussion on the main challenges of the technique, and potential means to mitigate and overcome them, will also be presented.
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Nanda SS, Kim MJ, Kim K, Papaefthymiou GC, Selvan ST, Yi DK. Recent advances in biocompatible semiconductor nanocrystals for immunobiological applications. Colloids Surf B Biointerfaces 2017; 159:644-654. [DOI: 10.1016/j.colsurfb.2017.08.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 08/15/2017] [Accepted: 08/17/2017] [Indexed: 12/30/2022]
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Peckys DB, Stoerger C, Latta L, Wissenbach U, Flockerzi V, de Jonge N. The stoichiometry of the TMEM16A ion channel determined in intact plasma membranes of COS-7 cells using liquid-phase electron microscopy. J Struct Biol 2017; 199:102-113. [PMID: 28559167 DOI: 10.1016/j.jsb.2017.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 11/29/2022]
Abstract
TMEM16A is a membrane protein forming a calcium-activated chloride channel. A homodimeric stoichiometry of the TMEM16 family of proteins has been reported but an important question is whether the protein resides always in a dimeric configuration in the plasma membrane or whether monomers of the protein are also present in its native state within in the intact plasma membrane. We have determined the stoichiometry of the human (h)TMEM16A within whole COS-7 cells in liquid. For the purpose of detecting TMEM16A subunits, single proteins were tagged by the streptavidin-binding peptide within extracellular loops accessible by streptavidin coated quantum dot (QD) nanoparticles. The labeled proteins were then imaged using correlative light microscopy and environmental scanning electron microscopy (ESEM) using scanning transmission electron microscopy (STEM) detection. The locations of 19,583 individual proteins were determined of which a statistical analysis using the pair correlation function revealed the presence of a dimeric conformation of the protein. The amounts of detected label pairs and single labels were compared between experiments in which the TMEM16A SBP-tag position was varied, and experiments in which tagged and non-tagged TMEM16A proteins were present. It followed that hTMEM16A resides in the plasma membrane as dimer only and is not present as monomer. This strategy may help to elucidate the stoichiometry of other membrane protein species within the context of the intact plasma membrane in future.
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Affiliation(s)
- Diana B Peckys
- Department of Biophysics, Saarland University, 66421 Homburg, Germany
| | - Christof Stoerger
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Lorenz Latta
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Ulrich Wissenbach
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Niels de Jonge
- INM - Leibniz Institute for New Materials, Saarland University, 66123 Saarbrücken, Germany; Department of Physics, Saarland University, 66123 Saarbrücken, Germany.
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DE JONGE N. Membrane protein stoichiometry studied in intact mammalian cells using liquid-phase electron microscopy. J Microsc 2017; 269:134-142. [DOI: 10.1111/jmi.12570] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/15/2017] [Accepted: 03/25/2017] [Indexed: 02/02/2023]
Affiliation(s)
- N. DE JONGE
- Leibniz Institute for New Materials; Saarbrücken Germany
- Department of Physics; University of Saarland; Saarbrücken Germany
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