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Fujisaku T, Tanabe R, Onoda S, Kubota R, Segawa TF, So FTK, Ohshima T, Hamachi I, Shirakawa M, Igarashi R. pH Nanosensor Using Electronic Spins in Diamond. ACS NANO 2019; 13:11726-11732. [PMID: 31538479 DOI: 10.1021/acsnano.9b05342] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nanoscale measurements provide insight into the nano world. For instance, nanometric spatiotemporal distribution of intracellular pH is regulated by and regulates a variety of biological processes. However, there is no general method to fabricate nanoscale pH sensors. Here, we, to endow pH-sensing functions, tailor the surface properties of a fluorescent nanodiamond (FND) containing nitrogen-vacancy centers (NV centers) by coating the FND with an ionic chemical layer. The longitudinal relaxation time T1 of the electron spins in the NV centers inside a nanodiamond modified by carboxyl groups on the particle surface was found to depend on ambient pH between pH 3 and pH 7, but not between pH 7 and pH 11. Therefore, a single particle of the carboxylated nanodiamond works as a nanometer-sized pH meter within a microscopic image and directly measures the nanometric local pH environment. Moreover, the pH dependence of an FND was changed by coating it with a polycysteine layer, which contains a multitude of thiol groups with higher pKa. The polycysteine-coated nanodiamond obtained a pH dependence between pH 7 and pH 11. The pH dependence of the FND was also observed in heavy water (D2O) buffers. This indicates that the pH dependence is not caused by magnetic noise induced by 1H nuclear spin fluctuations, but by electric noise induced by ion exchanges. Via our method, the sensitive pH range of the nanodiamond pH sensor can potentially be controlled by changing the ionic layer appropriately according to the target biological phenomena.
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Affiliation(s)
- Takahiro Fujisaku
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Ryotaro Tanabe
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
| | - Shinobu Onoda
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- Takasaki Advanced Radiation Research Institute , National Institutes for Quantum and Radiological Science and Technology , 1233 Watanuki , Takasaki , Gunma 370-1292 , Japan
| | - Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Takuya F Segawa
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Laboratory for Solid State Physics , ETH Zurich , Otto-Stern-Weg 1 , 8093 Zürich , Switzerland
| | - Frederick T-K So
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Takeshi Ohshima
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- Takasaki Advanced Radiation Research Institute , National Institutes for Quantum and Radiological Science and Technology , 1233 Watanuki , Takasaki , Gunma 370-1292 , Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering , Kyoto University , Kyoto 615-8510 , Japan
| | - Masahiro Shirakawa
- Department of Molecular Engineering, Graduate School of Engineering , Kyoto University , Nishikyo-Ku, Kyoto 615-8510 , Japan
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
| | - Ryuji Igarashi
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- National Institute for Radiological Sciences , National Institutes for Quantum and Radiological Science and Technology , Anagawa 4-9-1 , Inage-ku, Chiba 263-8555 , Japan
- JST , PRESTO, 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan
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Di Giuro CML, Shrestha N, Malli R, Groschner K, van Breemen C, Fameli N. Na +/Ca 2+ exchangers and Orai channels jointly refill endoplasmic reticulum (ER) Ca 2+ via ER nanojunctions in vascular endothelial cells. Pflugers Arch 2017; 469:1287-1299. [PMID: 28497275 PMCID: PMC5590033 DOI: 10.1007/s00424-017-1989-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 11/29/2022]
Abstract
We investigated the role of Na+/ Ca2+ exchange (NCX) in the refilling of endoplasmic reticulum (ER) Ca2+ in vascular endothelial cells under various conditions of cell stimulation and plasma membrane (PM) polarization. Better understanding of the mechanisms behind basic ER Ca2+ content regulation is important, since current hypotheses on the possible ultimate causes of ER stress point to deterioration of the Ca2+ transport mechanism to/from ER itself. We measured [Ca2+]i temporal changes by Fura-2 fluorescence under experimental protocols that inhibit a host of transporters (NCX, Orai, non-selective transient receptor potential canonical (TRPC) channels, sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), Na+/ K+ ATPase (NKA)) involved in the Ca2+ communication between the extracellular space and the ER. Following histamine-stimulated ER Ca2+ release, blockade of NCX Ca2+-influx mode (by 10 μM KB-R7943) diminished the ER refilling capacity by about 40%, while in Orai1 dominant negative-transfected cells NCX blockade attenuated ER refilling by about 60%. Conversely, inhibiting the ouabain sensitive NKA (10 nM ouabain), which may be localized in PM-ER junctions, increased the ER Ca2+ releasable fraction by about 20%, thereby supporting the hypothesis that this process of privileged ER refilling is junction-mediated. Junctions were observed in the cell ultrastructure and their main parameters of membrane separation and linear extension were (9.6 ± 3.8) nm and (128 ± 63) nm, respectively. Our findings point to a process of privileged refilling of the ER, in which NCX and store-operated Ca2+ entry via the stromal interaction molecule (STIM)-Orai system are the sole protagonists. These results shed light on the molecular machinery involved in the function of a previously hypothesized subplasmalemmal Ca2+ control unit during ER refilling with extracellular Ca2+.
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Affiliation(s)
| | - Niroj Shrestha
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Roland Malli
- Institute of Molecular Biology & Biochemistry, Medical University of Graz, Graz, Austria
| | - Klaus Groschner
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Cornelis van Breemen
- BC Children's Hospital Research Institute, Department of Anaesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nicola Fameli
- Institute of Biophysics, Medical University of Graz, Graz, Austria.
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Zhao M, Jia HH, Liu LZ, Bi XY, Xu M, Yu XJ, He X, Zang WJ. Acetylcholine attenuated TNF-α-induced intracellular Ca 2+ overload by inhibiting the formation of the NCX1-TRPC3-IP3R1 complex in human umbilical vein endothelial cells. J Mol Cell Cardiol 2017; 107:1-12. [PMID: 28395930 DOI: 10.1016/j.yjmcc.2017.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/16/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022]
Abstract
The endoplasmic reticulum (ER) forms discrete junctions with the plasma membrane (PM) that play a critical role in the regulation of Ca2+ signaling during cellular bioenergetics, apoptosis and autophagy. We have previously confirmed that acetylcholine can inhibit ER stress and apoptosis after inflammatory injury. However, limited research has focused on the effects of acetylcholine on ER-PM junctions. In this work, we evaluated the structure and function of the supramolecular sodium-calcium exchanger 1 (NCX1)-transient receptor potential canonical 3 (TRPC3)-inositol 1,4,5-trisphosphate receptor 1 (IP3R1) complex, which is involved in regulating Ca2+ homeostasis during inflammatory injury. The width of the ER-PM junctions of human umbilical vein endothelial cells (HUVECs) was measured in nanometres using transmission electron microscopy and a fluorescent probe for Ca2+. Protein-protein interactions were assessed by immunoprecipitation. Ca2+ concentration was measured using a confocal microscope. An siRNA assay was employed to silence specific proteins. Our results demonstrated that the peripheral ER was translocated to PM junction sites when induced by tumour necrosis factor-alpha (TNF-α) and that NCX1-TRPC3-IP3R1 complexes formed at these sites. After down-regulating the protein expression of NCX1 or IP3R1, we found that the NCX1-mediated inflow of Ca2+ and the release of intracellular Ca2+ stores were reduced in TNF-α-treated cells. We also observed that acetylcholine attenuated the formation of NCX1-TRPC3-IP3R1 complexes and maintained calcium homeostasis in cells treated with TNF-α. Interestingly, the positive effects of acetylcholine were abolished by the selective M3AChR antagonist darifenacin and by AMPK siRNAs. These results indicate that acetylcholine protects endothelial cells from TNF-alpha-induced injury, [Ca2+]cyt overload and ER-PM interactions, which depend on the muscarinic 3 receptor/AMPK pathway, and that acetylcholine may be a new inhibitor for suppressing [Ca2+]cyt overload.
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Affiliation(s)
- Ming Zhao
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Hang-Huan Jia
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Long-Zhu Liu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Xue-Yuan Bi
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Man Xu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Xiao-Jiang Yu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Xi He
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China
| | - Wei-Jin Zang
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, PR China.
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